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Sample records for long-range apparent motion

  1. Cortical dynamics of visual motion perception: short-range and long-range apparent motion.

    PubMed

    Grossberg, S; Rudd, M E

    1992-01-01

    This article describes further evidence for a new neural network theory of biological motion perception. The theory clarifies why parallel streams V1----V2, V1----MT, and V1----V2----MT exist for static form and motion form processing among the areas V1, V2, and MT of visual cortex. The theory suggests that the static form system (Static BCS) generates emergent boundary segmentations whose outputs are insensitive to direction-of-contrast and to direction-of-motion, whereas the motion form system (Motion BCS) generates emergent boundary segmentations whose outputs are insensitive to direction-of-contrast but sensitive to direction-of-motion. The theory is used to explain classical and recent data about short-range and long-range apparent motion percepts that have not yet been explained by alternative models. These data include beta motion, split motion, gamma motion and reverse-contrast gamma motion, delta motion, and visual inertia. Also included are the transition from group motion to element motion in response to a Ternus display as the interstimulus interval (ISI) decreases; group motion in response to a reverse-contrast Ternus display even at short ISIs; speed-up of motion velocity as interflash distance increases or flash duration decreases; dependence of the transition from element motion to group motion on stimulus duration and size, various classical dependencies between flash duration, spatial separation, ISI, and motion threshold known as Korte's laws; dependence of motion strength on stimulus orientation and spatial frequency; short-range and long-range form-color interactions; and binocular interactions of flashes to different eyes.

  2. Color signal integration for color discrimination along a long-range apparent motion trajectory.

    PubMed

    Nagai, Takehiro; Kimura, Hiroto; Nakauchi, Shigeki

    2013-01-01

    In contrast to the classical view that fundamental visual attributes such as color and motion are independently processed in the visual system (e.g. Livingstone and Hubel, 1987; Marr, 1982), recent studies have revealed various forms of cross-attribute interactions, such as averaging of color appearance along the motion trajectory of an object (Nishida et al., 2007). In this study, we investigated whether such color signal integration along a motion trajectory can be induced only by motion mechanisms having large receptive fields, without simple integration within direction-selective neurons with small receptive fields, like those in V1. The stimulus consisted of discs with long-range apparent motion along a circular trajectory. The stimulus onset asynchrony (SOA) between disc presentations controlled the strength of the apparent motion perception. We measured observers' sensitivity in detecting color modulation on the discs. The results showed that the measured sensitivity was lowest at SOAs corresponding to the strongest motion perception. This can be interpreted as follows: color signals were integrated along an apparent motion path, and this integration reduced chromatic sensitivity by averaging color signals. Another experiment that controlled apparent motion perception in a different way also supported this idea. However, this integration effect seemed to be linked to responses of motion detectors for the apparent motion stimuli, not directly to perceptual motion representation in the visual system. These results suggest that the human visual system handles color information from retinal inputs regarding moving objects based not only on a retinotopic coordinate but also on object-based coordinates, even when the moving object yields only long-range apparent motion.

  3. Pivotal role of hMT+ in long-range disambiguation of interhemispheric bistable surface motion.

    PubMed

    Duarte, João Valente; Costa, Gabriel Nascimento; Martins, Ricardo; Castelo-Branco, Miguel

    2017-10-01

    It remains an open question whether long-range disambiguation of ambiguous surface motion can be achieved in early visual cortex or instead in higher level regions, which concerns object/surface segmentation/integration mechanisms. We used a bistable moving stimulus that can be perceived as a pattern comprehending both visual hemi-fields moving coherently downward or as two widely segregated nonoverlapping component objects (in each visual hemi-field) moving separately inward. This paradigm requires long-range integration across the vertical meridian leading to interhemispheric binding. Our fMRI study (n = 30) revealed a close relation between activity in hMT+ and perceptual switches involving interhemispheric segregation/integration of motion signals, crucially under nonlocal conditions where components do not overlap and belong to distinct hemispheres. Higher signal changes were found in hMT+ in response to spatially segregated component (incoherent) percepts than to pattern (coherent) percepts. This did not occur in early visual cortex, unlike apparent motion, which does not entail surface segmentation. We also identified a role for top-down mechanisms in state transitions. Deconvolution analysis of switch-related changes revealed prefrontal, insula, and cingulate areas, with the right superior parietal lobule (SPL) being particularly involved. We observed that directed influences could emerge either from left or right hMT+ during bistable motion integration/segregation. SPL also exhibited significant directed functional connectivity with hMT+, during perceptual state maintenance (Granger causality analysis). Our results suggest that long-range interhemispheric binding of ambiguous motion representations mainly reflect bottom-up processes from hMT+ during perceptual state maintenance. In contrast, state transitions maybe influenced by high-level regions such as the SPL. Hum Brain Mapp 38:4882-4897, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley

  4. Motion planning in unstructured road for intelligent vehicle with long-range perception

    NASA Astrophysics Data System (ADS)

    Shi, Chaoxia; Wang, Yanqing; Yang, Jingyu; Liu, Hanxiang

    2011-10-01

    We present a novel motion planning method for intelligent vehicle with long-range perception under the uncertain constraints of unstructured road boundary on the basis of obstacle roadside fusion strategy and beam curvature method . Not only does this method inherit the advantages of reliability, smoothness and speediness from LCM, but also it can produce more reasonable path than traditional LCM does by virtue of the global information acquired by long-range sensors.

  5. Masking and color inheritance along the apparent motion path.

    PubMed

    Souto, David; Johnston, Alan

    2012-07-30

    Long-range apparent motion is the illusory motion that can be perceived when two static and distant stimuli are presented in succession. Within some spatiotemporal range not only is motion sensed, but it appears as if one stimulus is displaced from one place to another (termed beta or optimal motion). Several groups have found that this illusory percept can interact with perception of a physically present stimulus, but some disagree on the origin of these interactions. We know little about how suppressive effects depend on feature-similarity between a target and the stimuli in apparent motion (inducers)-which would indicate an early perceptual locus-or even about the minimal conditions under which to obtain this effect. Unlike early studies that used a two-stroke apparent motion paradigm, we were able to demonstrate that motion can mask stimuli presented at interpolated locations along the apparent motion path, as shown by the elevation of contrast thresholds compared to a control condition. Apparent motion masking depended on color similarity between target and inducers. Further, we found evidence that the color of inducers alters the apparent color of intervening gray probes, indicating some inheritance or chromatic averaging across distant locations, but no clear evidence of predictive updating. Finally, the analysis of the presentation times delivering maximal masking effects suggests a predictive interpolation process is responsible for interference by apparent motion filling-in. We discuss alternative mechanisms, in particular the possible role of apparent-motion-induced metacontrast masking in generating this pattern of results.

  6. The apparent anomalous, weak, long-range acceleration of Pioneer 10 and 11

    SciTech Connect

    Anderson, J.D.; Lau, E.L.; Turyshev, S.G.; Laing, P.A.; Liu, A.S.; Nieto, M.M.

    1999-07-01

    Recently the authors reported that radio Doppler data generated by NASA`s Deep Space Network (DSN) with the Pioneer 10 and 11 spacecraft indicate an apparent anomalous, constant, spacecraft acceleration with a magnitude {approximately}8.5 {times} 10{sup {minus}8} cm s{sup {minus}2}, directed towards the Sun. Analysis of similar Doppler and ranging data from the Galileo and Ulysses spacecraft yielded ambiguous results for the anomalous acceleration, but the analysis was useful in that it ruled out the possibility of a systematic error in the DSN Doppler system that could easily be mistaken as a spacecraft acceleration. Here they present some new results, including a critique of the suggestion that the anomalous acceleration could be caused by collimated thermal emission. Based on upgraded JPL software for the Pioneer 10 orbit determination, and on a new data interval from January 1987 to July 1998, their best estimate of the average Pioneer 10 acceleration directed towards the Sun is 7.20 {sup {minus}} 0.11 {times} 10{sup {minus}8} cm s{sup {minus}2}.

  7. Apparent extended body motions in depth

    NASA Technical Reports Server (NTRS)

    Hecht, Heiko; Proffitt, Dennis R.

    1991-01-01

    Five experiments were designed to investigate the influence of three-dimensional (3-D) orientation change on apparent motion. Projections of an orientation-specific 3-D object were sequentially flashed in different locations and at different orientations. Such an occurrence could be resolved by perceiving a rotational motion in depth around an axis external to the object. Consistent with this proposal, it was found that observers perceived curved paths in depth. Although the magnitude of perceived trajectory curvature often fell short of that required for rotational motions in depth (3-D circularity), judgments of the slant of the virtual plane on which apparent motions occurred were quite close to the predictions of a model that proposes circular paths in depth.

  8. Repetitive transcranial magnetic stimulation of human MT+ reduces apparent motion perception.

    PubMed

    Matsuyoshi, Daisuke; Hirose, Nobuyuki; Mima, Tatsuya; Fukuyama, Hidenao; Osaka, Naoyuki

    2007-12-18

    We investigated the effects of repetitive transcranial magnetic stimulation (rTMS) over the human cerebral cortex on apparent motion perception. Previous studies have shown that human extrastriate visual area MT+ (V5) processes not only real but also apparent motion. However, the functional relevance of MT+ on long-range apparent motion perception remains unclear. Here, we show direct evidence for the involvement of MT+ in apparent motion perception using rTMS, which is known to temporarily inhibit a localized region in the cerebral cortex. The results showed that apparent motion perception decreased after applying rTMS over MT+, but not after applying rTMS over the control region (inferior temporal gyrus). The decrease in performance caused by applying rTMS to MT+ suggests that MT+ is a causally responsible region for apparent motion perception, and thus, further supports the idea that MT+ plays a major role in the perception of motion.

  9. Ambiguity in Tactile Apparent Motion Perception

    PubMed Central

    Liaci, Emanuela; Bach, Michael; Tebartz van Elst, Ludger; Heinrich, Sven P.; Kornmeier, Jürgen

    2016-01-01

    Background In von Schiller’s Stroboscopic Alternative Motion (SAM) stimulus two visually presented diagonal dot pairs, located on the corners of an imaginary rectangle, alternate with each other and induce either horizontal, vertical or, rarely, rotational motion percepts. SAM motion perception can be described by a psychometric function of the dot aspect ratio (“AR”, i.e. the relation between vertical and horizontal dot distances). Further, with equal horizontal and vertical dot distances (AR = 1) perception is biased towards vertical motion. In a series of five experiments, we presented tactile SAM versions and studied the role of AR and of different reference frames for the perception of tactile apparent motion. Methods We presented tactile SAM stimuli and varied the ARs, while participants reported the perceived motion directions. Pairs of vibration stimulators were attached to the participants’ forearms and stimulator distances were varied within and between forearms. We compared straight and rotated forearm conditions with each other in order to disentangle the roles of exogenous and endogenous reference frames. Results Increasing the tactile SAM’s AR biased perception towards vertical motion, but the effect was weak compared to the visual modality. We found no horizontal disambiguation, even for very small tactile ARs. A forearm rotation by 90° kept the vertical bias, even though it was now coupled with small ARs. A 45° rotation condition with crossed forearms, however, evoked a strong horizontal motion bias. Discussion Existing approaches to explain the visual SAM bias fail to explain the current tactile results. Particularly puzzling is the strong horizontal bias in the crossed-forearm conditions. In the case of tactile apparent motion, there seem to be no fixed priority rule for perceptual disambiguation. Rather the weighting of available evidence seems to depend on the degree of stimulus ambiguity, the current situation and on the perceptual

  10. Coupled quantum-classical method for long range charge transfer: relevance of the nuclear motion to the quantum electron dynamics

    NASA Astrophysics Data System (ADS)

    da Silva, Robson; Hoff, Diego A.; Rego, Luis G. C.

    2015-04-01

    Charge and excitonic-energy transfer phenomena are fundamental for energy conversion in solar cells as well as artificial photosynthesis. Currently, much interest is being paid to light-harvesting and energy transduction processes in supramolecular structures, where nuclear dynamics has a major influence on electronic quantum dynamics. For this reason, the simulation of long range electron transfer in supramolecular structures, under environmental conditions described within an atomistic framework, has been a difficult problem to study. This work describes a coupled quantum mechanics/molecular mechanics method that aims at describing long range charge transfer processes in supramolecular systems, taking into account the atomistic details of large molecular structures, the underlying nuclear motion, and environmental effects. The method is applied to investigate the relevance of electron-nuclei interaction on the mechanisms for photo-induced electron-hole pair separation in dye-sensitized interfaces as well as electronic dynamics in molecular structures.

  11. Coupled quantum-classical method for long range charge transfer: relevance of the nuclear motion to the quantum electron dynamics.

    PubMed

    da Silva, Robson; Hoff, Diego A; Rego, Luis G C

    2015-04-10

    Charge and excitonic-energy transfer phenomena are fundamental for energy conversion in solar cells as well as artificial photosynthesis. Currently, much interest is being paid to light-harvesting and energy transduction processes in supramolecular structures, where nuclear dynamics has a major influence on electronic quantum dynamics. For this reason, the simulation of long range electron transfer in supramolecular structures, under environmental conditions described within an atomistic framework, has been a difficult problem to study. This work describes a coupled quantum mechanics/molecular mechanics method that aims at describing long range charge transfer processes in supramolecular systems, taking into account the atomistic details of large molecular structures, the underlying nuclear motion, and environmental effects. The method is applied to investigate the relevance of electron-nuclei interaction on the mechanisms for photo-induced electron-hole pair separation in dye-sensitized interfaces as well as electronic dynamics in molecular structures.

  12. Indication, from Pioneer 10/11, Galileo, and Ulysses Data, of an Apparent Anomalous, Weak, Long-Range Acceleration

    SciTech Connect

    Anderson, J.D.; Lau, E.L.; Turyshev, S.G.; Laing, P.A.; Liu, A.S.; Nieto, M.M.

    1998-10-01

    Radio metric data from the Pioneer 10/11, Galileo, and Ulysses spacecraft indicate an apparent anomalous, constant, acceleration acting on the spacecraft with a magnitude {approximately}8.5{times}10{sup {minus}8} cm/s{sup 2} , directed towards the Sun. Two independent codes and physical strategies have been used to analyze the data. A number of potential causes have been ruled out. We discuss future kinematic tests and possible origins of the signal. {copyright} {ital 1998} {ital The American Physical Society}

  13. Curved apparent motion induced by amodal completion

    PubMed Central

    Feldman, Jacob; Singh, Manish

    2012-01-01

    We investigated whether amodal completion can bias apparent motion (AM) to deviate from its default straight path toward a longer curved path, which would violate the well-established principle that AM follows the shortest possible path. Observers viewed motion sequences of two alternating rectangular tokens positioned at the ends of a semicircular occluder, with varying interstimulus intervals (ISIs; 100–500 ms). At short ISIs, observers tended to report simple straight-path motion—that is, outside the occluder. But at long ISIs, they became increasingly likely to report a curved-path motion behind the occluder. This tendency toward reporting curved-path motion was influenced by the shape of tokens, display orientation, the gap between tokens and the occluder, and binocular depth cues. Our results suggest that the visual system tends to minimize unexplained absence of a moving object, as well as its path length, such that AM deviates from the shortest path when amodal integration of motion trajectory behind the curved occluder can account for the objective invisibility of the object during the ISI. PMID:22069082

  14. Alternative perceptual states 'apparent motion' and 'perceived simultaneity' lead to differences of induced EEG rhythms.

    PubMed

    Kompass, R; Hüfner, R; Schröger, E; Kaernbach, C; Geissler, H G

    2000-12-01

    An investigation of the cortical response (EEG) to periodically presented stimuli producing an ambiguity between long-range apparent motion and flicker is reported. ERPs to stimulus onsets differed slightly between the two percepts, in accordance with the results of Manning et al. (1988), Selmes et al. (1997). Induced rhythms exhibited a strong increase in induced beta and gamma powers at electrode positions T7 and T8 during the perception of apparent motion in two out of 10 participants. In addition, a small overall increase in alpha power at 12-13 Hz and a decrease in delta power below 3.5 Hz during perceived motion were found. The results indicate that a variety of different neural rhythms are involved in the perception of long-range apparent motion.

  15. The role of multi-area interactions for the computation of apparent motion.

    PubMed

    Deco, Gustavo; Roland, Per

    2010-07-01

    Apparent motion (AM) is a robust visual illusion, in which fast displays of static objects in successively different positions elicit the perception of object motion. Neurons in higher order areas 21 and 19 compute object motion under such conditions and send feedback to early visual areas 18 and 17, which is instrumental in eliciting computation of motion in those very areas. To explore the computational dynamics of AM, we made a neural field model consisting of two one-dimensional rings of simple neurons expressing firing rates, one for areas 17/18 and one for areas 19/21. The model neurons, without any orientation or direction selectivity, computed apparent motion for the range of space-timings of stimuli associated with short- and long-range AM in humans. The computation of long-range AM in 17/18 required two model areas and the presence of feedback and conduction/computation delays between those areas. As in the in vivo experiments of long-range AM, the stationary stimuli were initially mapped as stationary in model area 17/18, but after the feedback also these lower areas computed AM. The dynamics of the two-area network produces short-range and long-range apparent motion for a large range of feedback strengths and a small range of lateral excitation near the bifurcation to an amplitude instability. The computation of AM in higher order areas was due to the neurons in these areas having large receptive fields as a consequence of divergent feed-forward connectivity. This implies that these areas compute long-range AM when early areas 17 and 18 do not, and therefore higher order areas must enslave lower order areas to compute the same, if the whole network is to arrive at a coherent perceptual solution. Copyright (c) 2010 Elsevier Inc. All rights reserved.

  16. The influence of spontaneous brain oscillations on apparent motion perception.

    PubMed

    Sanders, Lia Lira Olivier; Auksztulewicz, Ryszard; Hohlefeld, Friederike U; Busch, Niko A; Sterzer, Philipp

    2014-11-15

    A good example of inferential processes in perception is long-range apparent motion (AM), the illusory percept of visual motion that occurs when two spatially distinct stationary visual objects are presented in alternating sequence. The AM illusion is strongest at presentation frequencies around 3 Hz. At lower presentation frequencies, the percept varies from trial to trial between AM and sequential alternation, while at higher frequencies perception varies between AM and two simultaneously flickering objects. Previous studies have demonstrated that prestimulus alpha oscillations explain trial-to-trial variability in detection performance for visual stimuli presented at threshold. In the present study, we investigated whether fluctuations of prestimulus alpha oscillations can also account for variations in AM perception. Prestimulus alpha power was stronger when observers reported AM perception in subsequent trials with low presentation frequencies, while at high presentation frequencies there were no significant differences in alpha power preceding AM and veridical flicker perception. Moreover, when observers perceived AM the prestimulus functional connectivity between frontal and occipital channels was increased in the alpha band, as revealed by the imaginary part of coherency, which is insensitive to artefacts from volume conduction. Dynamic causal modelling of steady-state responses revealed that the most likely direction of this fronto-occipital connectivity was from frontal to occipital sources. These results point to a role of ongoing alpha oscillations in the inferential process that gives rise to the perception of AM and suggest that fronto-occipital interactions bias perception towards internally generated predictions.

  17. Apparent Biological Motion in First and Third Person Perspective

    PubMed Central

    Scandola, Michele; Orvalho, Veronica; Candidi, Matteo

    2016-01-01

    Apparent biological motion is the perception of plausible movements when two alternating images depicting the initial and final phase of an action are presented at specific stimulus onset asynchronies. Here, we show lower subjective apparent biological motion perception when actions are observed from a first relative to a third visual perspective. These findings are discussed within the context of sensorimotor contributions to body ownership. PMID:27708754

  18. Apparent motion enhances visual rhythm discrimination in infancy.

    PubMed

    Brandon, Melissa; Saffran, Jenny R

    2011-05-01

    Many studies have demonstrated that infants exhibit robust auditory rhythm discrimination, but research on infants' perception of visual rhythm is limited. In particular, the role of motion in infants' perception of visual rhythm remains unknown, despite the prevalence of motion cues in naturally occurring visual rhythms. In the present study, we examined the role of motion in 7-month-old infants' discrimination of visual rhythms by comparing experimental conditions with apparent motion in the stimuli versus stationary rhythmic stimuli. Infants succeeded at discriminating visual rhythms only when the visual rhythm occurred with an apparent motion component. These results support the view that motion plays a role in infants' perception of visual temporal information, consistent with the manner in which natural rhythms appear in the visual world.

  19. Magnetoencephalographic study of speed-dependent responses in apparent motion.

    PubMed

    Bakardjian, Hovagim; Uchida, Akira; Endo, Hiroshi; Takeda, Tsunehiro

    2002-10-01

    There have been only few studies of visually-evoked cortical responses to apparent motion as a function of stimulus speed. Most earlier findings on evoked peak magnitudes and latencies, utilizing various types of smooth and apparent motion stimuli, have demonstrated that greater spatial separation/speed resulted in enhanced peak magnitudes, decreasing onset latencies in individual extrastriate neurons and in shorter motor reaction times in subjects. However, some reports using partial-coverage magnetoencephalography stated that increasing the stimulus displacement actually triggered a substantial reduction of the evoked main peak latency while the magnitude showed no clear change. To resolve the issue of the dependency of evoked responses on stimulus speed in apparent motion, we presented moving bar stimuli to 6 subjects at velocities within a 100 fold range and investigated the ensuing evoked visual cortical activity using a whole-cortex magnetoencephalograph. The magnitude and the latency of the first major evoked peak M1 was measured and compared for 6 discrete bar-stimuli displacements in all subjects. Our results showed clearly that the M1 peak response magnitudes increased in a nonlinear way with higher apparent speeds (larger displacements), in compliance with the logarithmic Fechner law. We observed also that the fluctuations of the mean evoked M1 peak latency (140+/-10.6 ms) did not reach significance over the tested range of stimulus velocities. These findings probably reflect global motion processing mechanisms which rely on nonlinear speed-dependent feedback connectivity between striate and extrastriate visual cortex areas.

  20. Long Range Technology Planning.

    ERIC Educational Resources Information Center

    Ambron, Sueann, Ed.

    1986-01-01

    This summary of a meeting of the Apple Education Advisory Council, on long range technology plans at the state, county, district, and school levels, includes highlights from group discussions on future planning, staff development, and curriculum. Three long range technology plans at the state level are provided: Long Range Educational Technology…

  1. Long Range Technology Planning.

    ERIC Educational Resources Information Center

    Ambron, Sueann, Ed.

    1986-01-01

    This summary of a meeting of the Apple Education Advisory Council, on long range technology plans at the state, county, district, and school levels, includes highlights from group discussions on future planning, staff development, and curriculum. Three long range technology plans at the state level are provided: Long Range Educational Technology…

  2. Tuning for temporal interval in human apparent motion detection.

    PubMed

    Bours, Roger J E; Stuur, Sanne; Lankheet, Martin J M

    2007-01-08

    Detection of apparent motion in random dot patterns requires correlation across time and space. It has been difficult to study the temporal requirements for the correlation step because motion detection also depends on temporal filtering preceding correlation and on integration at the next levels. To specifically study tuning for temporal interval in the correlation step, we performed an experiment in which prefiltering and postintegration were held constant and in which we used a motion stimulus containing coherent motion for a single interval value only. The stimulus consisted of a sparse random dot pattern in which each dot was presented in two frames only, separated by a specified interval. On each frame, half of the dots were refreshed and the other half was a displaced reincarnation of the pattern generated one or several frames earlier. Motion energy statistics in such a stimulus do not vary from frame to frame, and the directional bias in spatiotemporal correlations is similar for different interval settings. We measured coherence thresholds for left-right direction discrimination by varying motion coherence levels in a Quest staircase procedure, as a function of both step size and interval. Results show that highest sensitivity was found for an interval of 17-42 ms, irrespective of viewing distance. The falloff at longer intervals was much sharper than previously described. Tuning for temporal interval was largely, but not completely, independent of step size. The optimal temporal interval slightly decreased with increasing step size. Similarly, the optimal step size decreased with increasing temporal interval.

  3. Altered perception of apparent motion in schizophrenia spectrum disorder.

    PubMed

    Tschacher, Wolfgang; Dubouloz, Priscilla; Meier, Rahel; Junghan, Uli

    2008-06-30

    Apparent motion (AM), the Gestalt perception of motion in the absence of physical motion, was used to study perceptual organization and neurocognitive binding in schizophrenia. Associations between AM perception and psychopathology as well as meaningful subgroups were sought. Circular and stroboscopic AM stimuli were presented to 68 schizophrenia spectrum patients and healthy participants. Psychopathology was measured using the Positive and Negative Syndrome Scale (PANSS). Psychopathology was related to AM perception differentially: Positive and disorganization symptoms were linked to reduced gestalt stability; negative symptoms, excitement and depression had opposite regression weights. Dimensions of psychopathology thus have opposing effects on gestalt perception. It was generally found that AM perception was closely associated with psychopathology. No difference existed between patients and controls, but two latent classes were found. Class A members who had low levels of AM stability made up the majority of inpatients and control subjects; such participants were generally young and male, with short reaction times. Class B typically contained outpatients and some control subjects; participants in class B were older and showed longer reaction times. Hence AM perceptual dysfunctions are not specific for schizophrenia, yet AM may be a promising stage marker.

  4. Illusory motion and mislocalization of temporally offset target in apparent motion display.

    PubMed

    Hidaka, Souta; Nagai, Masayoshi

    2013-01-01

    When a visual target briefly appears in a display containing visual motion information, the perceived position of the target is mislocalized forward along its direction of motion. This phenomenon is assumed to be caused by the interaction between the transient onset signal of the target and motion information. However, while transient onset and offset signals are important for the establishment of our perceptual awareness, it has not been examined whether transient offset signals could be also effective for target mislocalization. Here, we demonstrate that shifts in perceived position occurred for a visual target containing a temporally transient offset signal in an apparent motion (AM) display. First, with horizontal AM, we found that illusory motion was perceived when a static target transiently and repeatedly blinked at a fixed position. The perceived direction of the illusory motion was in counter-phase with that of the AM stimuli. Further, we confirmed that illusory motion was frequently perceived when (1) the eccentricity of the target was larger, (2) offset duration was longer, and (3) smoother AM was perceived. Illusory motion was not perceived unless AM stimuli were presented after the offset signal, while illusory motion still occurred when the AM stimuli disappeared before the offset signal. In addition, we found that mislocalization of the target's perceived position actually occurred in a direction opposite to AM. These findings suggest that a transient offset signal could trigger perceptual mislocalization of static visual stimuli by interacting with motion information in a postdictive manner.

  5. Long Range Fast Tool Servo

    DTIC Science & Technology

    1993-05-31

    AD-A271 614 r, FINAL REPORT w to I OFFICE OF NAVAL RESEARCH [I on * LONG RANGE FAST TOOL SERVO I ONR CONTRACT NO. N00014-92-J-4082-PII Covering the...n I I 1 INTRODUCTION The PEC’s MAC 100 Fast Tool Servo (FTS) System has demonstrated the efficacy of fabricating off-axis parabolic segments on axis...by utilizing a fast tool motion to machine non-rotationally symmetric surfaces [1]. The key to this technique was a servo for the tool motion that had

  6. Institutional Long Range Planning.

    ERIC Educational Resources Information Center

    Caldwell Community Coll. and Technical Inst., Lenoir, NC.

    Long-range institutional planning has been in effect at Caldwell Community College and Technical Institute since 1973. The first step in the process was the identification of planning areas: administration, organization, educational programs, learning resources, student services, faculty, facilities, maintenance/operation, and finances. The major…

  7. Long Range Plan.

    ERIC Educational Resources Information Center

    Jefferson Coll., Hillsboro, MO.

    This document presents Jefferson College's "Long Range Plan," which is intended to provide the College's governing board, administration, and faculty and staff with a task-oriented blueprint for maximizing the delivery of higher education services to students and the community in a predictable, programmatic, and fiscally sound manner.…

  8. Long Range Facilities Planning

    DTIC Science & Technology

    1982-04-01

    Richard Muther range facilities Many alterna- analysis indi- cated that if NASSCO ever expected to surpass its output of the last several years, current...Marine Engineers (SNAME) SP-1 Panel Meeting. The Maritime Administration had Richard Muther (an authority on long range facility planning) address a

  9. Long range chromatin organization

    PubMed Central

    Acuña, Luciana I Gómez; Kornblihtt, Alberto R

    2014-01-01

    Splicing is a predominantly co-transcriptional process that has been shown to be tightly coupled to transcription. Chromatin structure is a key factor that mediates this functional coupling. In light of recent evidence that shows the importance of higher order chromatin organization in the coordination and regulation of gene expression, we discuss here the possible roles of long-range chromatin organization in splicing and alternative splicing regulation. PMID:25764333

  10. Failure of signed chromatic apparent motion with luminance masking.

    PubMed

    Yoshizawa, Tatsuya; Mullen, Kathy T; Baker, Curtis L

    2003-03-01

    It has been suggested that there are two types of chromatic motion mechanisms: signed chromatic motion, in which correspondence across successive frames is based on chromatic content of image regions, and unsigned chromatic motion based on movement of chromatically-defined borders. We investigate whether signed and unsigned red-green chromatic motion are mediated by a genuinely chromatic mechanism. Direction discrimination of signed and unsigned red-green chromatic motion were measured in the presence of a dynamic luminance masking noise. Increasing the luminance noise contrast systematically impaired signed motion, regardless of contrast and speed. This result suggests that signed red-green chromatic motion is derived from a luminance-based signal, rather than a genuinely chromatic motion mechanism. In the case of unsigned chromatic motion, there is no effect of luminance masking noise, indicating there exists a genuine chromatic mechanism for second-order motion perception.

  11. Apparent motion distorts the shape of a stimulus briefly presented along the motion path.

    PubMed

    Khuu, Sieu K; Phu, Jack; Khambiye, Shazaan

    2010-11-24

    We examined whether motion blur accompanying apparent motion (AM) affects the shape of a stimulus presented in the motion path. In a two-alternative forced-choice procedure, observers judged the shape of a Gaussian test stimulus flashed in the path of motion, relative to a reference stimulus, which was a circular Gaussian stimulus located away from the path of motion. In Experiment 1, we report that the test stimulus was affected by AM and its perceived width was wider than its actual width, and counteracting this distortion, shape discrimination thresholds coincided with a test stimulus that was physically "thinner" than the reference stimulus. Shape distortion correlated with the strength of AM (Experiment 2) and increased within the range of inter-stimulus intervals used to induce AM and with retinal eccentricity but was eliminated when the test stimulus was made "hard-edged" (Experiment 3) or when the stimulus does not overlap with the motion path (Experiment 4). In Experiment 5, we demonstrate that the effect is present for dichoptic presentations. These results can be accounted for by a process in which the neural representation of AM generated by higher cortical areas feedback to interfere with the coding of stimulus shape by units located along the trajectory of AM.

  12. Processing of targets in smooth or apparent motion along the vertical in the human brain: an fMRI study.

    PubMed

    Maffei, Vincenzo; Macaluso, Emiliano; Indovina, Iole; Orban, Guy; Lacquaniti, Francesco

    2010-01-01

    Neural substrates for processing constant speed visual motion have been extensively studied. Less is known about the brain activity patterns when the target speed changes continuously, for instance under the influence of gravity. Using functional MRI (fMRI), here we compared brain responses to accelerating/decelerating targets with the responses to constant speed targets. The target could move along the vertical under gravity (1g), under reversed gravity (-1g), or at constant speed (0g). In the first experiment, subjects observed targets moving in smooth motion and responded to a GO signal delivered at a random time after target arrival. As expected, we found that the timing of the motor responses did not depend significantly on the specific motion law. Therefore brain activity in the contrast between different motion laws was not related to motor timing responses. Average BOLD signals were significantly greater for 1g targets than either 0g or -1g targets in a distributed network including bilateral insulae, left lingual gyrus, and brain stem. Moreover, in these regions, the mean activity decreased monotonically from 1g to 0g and to -1g. In the second experiment, subjects intercepted 1g, 0g, and -1g targets either in smooth motion (RM) or in long-range apparent motion (LAM). We found that the sites in the right insula and left lingual gyrus, which were selectively engaged by 1g targets in the first experiment, were also significantly more active during 1g trials than during -1g trials both in RM and LAM. The activity in 0g trials was again intermediate between that in 1g trials and that in -1g trials. Therefore in these regions the global activity modulation with the law of vertical motion appears to hold for both RM and LAM. Instead, a region in the inferior parietal lobule showed a preference for visual gravitational motion only in LAM but not RM.

  13. Depth representation of moving 3-D objects in apparent-motion path.

    PubMed

    Hidaka, Souta; Kawachi, Yousuke; Gyoba, Jiro

    2008-01-01

    Apparent motion is perceived when two objects are presented alternately at different positions. The internal representations of apparently moving objects are formed in an apparent-motion path which lacks physical inputs. We investigated the depth information contained in the representation of 3-D moving objects in an apparent-motion path. We examined how probe objects-briefly placed in the motion path-affected the perceived smoothness of apparent motion. The probe objects comprised 3-D objects which were defined by being shaded or by disparity (convex/concave) or 2-D (flat) objects, while the moving objects were convex/concave objects. We found that flat probe objects induced a significantly smoother motion perception than concave probe objects only in the case of the convex moving objects. However, convex probe objects did not lead to smoother motion as the flat objects did, although the convex probe objects contained the same depth information for the moving objects. Moreover, the difference between probe objects was reduced when the moving objects were concave. These counterintuitive results were consistent in conditions when both depth cues were used. The results suggest that internal representations contain incomplete depth information that is intermediate between that of 2-D and 3-D objects.

  14. Tracing path-guided apparent motion in human primary visual cortex V1

    PubMed Central

    Akselrod, Michel; Herzog, Michael H.; Öğmen, Haluk

    2014-01-01

    Vision is a constructive process. For example, a square, flashed at two distinct locations one after the other, appears to move smoothly between the two locations rather than as two separate flashes (apparent motion). Apparent motion is usually perceived along the shortest path between locations. Previous studies have shown that retinotopic activity in V1 correlates well with the subjective filling-in in apparent motion. If V1 activity truly reflects illusory motion, it should flexibly reflect filling-in of any path, subjectively perceived. Here, we used a path-guided apparent motion paradigm in which a faint cue, presented in addition to the squares, leads to a curved illusory motion path. We found retinotopic activity in V1 to reflect the illusory filling-in of the curved path, similarly to filling-in with linear, shortest paths. Moreover, our results show that activity along the linear path was less selective to stimulus conditions than the activity along the curved path. This finding may be interpreted as V1 activity representing a small subset of infinitely many possible solutions to ambiguous stimuli, whilst giving more weight to the shortest path/energy solution. PMID:25317907

  15. Deciding what to see: the role of intention and attention in the perception of apparent motion.

    PubMed

    Kohler, Axel; Haddad, Leila; Singer, Wolf; Muckli, Lars

    2008-03-01

    Apparent motion is an illusory perception of movement that can be induced by alternating presentations of static objects. Already in Wertheimer's early investigation of the phenomenon [Wertheimer, M. (1912). Experimentelle Studien über das Sehen von Bewegung. Zeitschrift fur Psychologie, 61, 161-265], he mentions that voluntary attention can influence the way in which an ambiguous apparent motion display is perceived. But until now, few studies have investigated how strong the modulation of apparent motion through attention can be under different stimulus and task conditions. We used bistable motion quartets of two different sizes, where the perception of vertical and horizontal motion is equally likely. Eleven observers participated in two experiments. In Experiment 1, participants were instructed to either (a) hold the current movement direction as long as possible, (b) passively view the stimulus, or (c) switch the movement directions as quickly as possible. With the respective instructions, observers could almost double phase durations in (a) and more than halve durations in (c) relative to the passive condition. This modulation effect was stronger for the large quartets. In Experiment 2, observers' attention was diverted from the stimulus by a detection task at fixation while they still had to report their conscious perception. This manipulation prolonged dominance durations for up to 100%. The experiments reveal a high susceptibility of ambiguous apparent motion to attentional modulation. We discuss how feature- and space-based attention mechanisms might contribute to those effects.

  16. Detection of Counter-Changing Contrast: Second-Order Apparent Motion Without Postrectification Motion-Energy Analysis or Salience Mapping/Feature Tracking

    ERIC Educational Resources Information Center

    Gilroy, Lee A.; Hock, Howard S.

    2004-01-01

    The perception of 2nd-order, texture-contrast-defined motion was studied for apparent-motion stimuli composed of a pair of spatially displaced, simultaneously visible checkerboards. It was found that background-relative, counter-changing contrast provided the informational basis for the perception of 2nd-order apparent motion; motion began where…

  17. Detection of Counter-Changing Contrast: Second-Order Apparent Motion Without Postrectification Motion-Energy Analysis or Salience Mapping/Feature Tracking

    ERIC Educational Resources Information Center

    Gilroy, Lee A.; Hock, Howard S.

    2004-01-01

    The perception of 2nd-order, texture-contrast-defined motion was studied for apparent-motion stimuli composed of a pair of spatially displaced, simultaneously visible checkerboards. It was found that background-relative, counter-changing contrast provided the informational basis for the perception of 2nd-order apparent motion; motion began where…

  18. A Self-Alignment Algorithm for SINS Based on Gravitational Apparent Motion and Sensor Data Denoising

    PubMed Central

    Liu, Yiting; Xu, Xiaosu; Liu, Xixiang; Yao, Yiqing; Wu, Liang; Sun, Jin

    2015-01-01

    Initial alignment is always a key topic and difficult to achieve in an inertial navigation system (INS). In this paper a novel self-initial alignment algorithm is proposed using gravitational apparent motion vectors at three different moments and vector-operation. Simulation and analysis showed that this method easily suffers from the random noise contained in accelerometer measurements which are used to construct apparent motion directly. Aiming to resolve this problem, an online sensor data denoising method based on a Kalman filter is proposed and a novel reconstruction method for apparent motion is designed to avoid the collinearity among vectors participating in the alignment solution. Simulation, turntable tests and vehicle tests indicate that the proposed alignment algorithm can fulfill initial alignment of strapdown INS (SINS) under both static and swinging conditions. The accuracy can either reach or approach the theoretical values determined by sensor precision under static or swinging conditions. PMID:25923932

  19. Direction of visual apparent motion driven by perceptual organization of cross-modal signals.

    PubMed

    Roseboom, Warrick; Kawabe, Takahiro; Nishida, Shin'ya

    2013-01-04

    A critical function of the human brain is to determine the relationship between sensory signals. In the case of signals originating from different sensory modalities, such as audition and vision, several processes have been proposed that may facilitate perception of correspondence between two signals despite any temporal discrepancies in physical or neural transmission. One proposal, temporal ventriloquism, suggests that audio-visual temporal discrepancies can be resolved with a capture of visual event timing by that of nearby auditory events. Such an account implies a fundamental change in the timing representations of the involved events. Here we examine if such changes are necessary to account for a recently demonstrated effect, the modulation of visual apparent motion direction by audition. By contrast, we propose that the effect is driven by segmentation of the visual sequence on the basis of perceptual organization in the cross-modal sequence. Using different sequences of cross-modal (auditory and tactile) events, we found that the direction of visual apparent motion was not consistent with a temporal capture explanation. Rather, reports of visual apparent motion direction were dictated by perceptual organization within cross-modal sequences, determined on the basis of apparent relatedness. This result adds to the growing literature indicating the importance of apparent relatedness and sequence segmentation in apparent timing. Moreover, it demonstrates that, contrary to previous findings, cross-modal interaction can play a critical role in determining organization of signals within a single sensory modality.

  20. Optimal displacement in apparent motion and quadrature models of motion sensing

    NASA Technical Reports Server (NTRS)

    Watson, Andrew B.

    1990-01-01

    A grating appears to move if it is displaced by some amount between two brief presentations, or between multiple successive presentations. A number of recent experiments have examined the influence of displacement size upon either the sensitivity to motion, or upon the induced motion aftereffect. Several recent motion models are based upon quadrature filters that respond in opposite quadrants in the spatiotemporal frequency plane. Predictions of the quadrature model are derived for both two-frame and multiframe displays. Quadrature models generally predict an optimal displacement of 1/4 cycle for two-frame displays, but in the multiframe case the prediction depends entirely on the frame rate.

  1. Visual apparent motion can be modulated by task-irrelevant lexical information.

    PubMed

    Chen, Lihan; Zhou, Xiaolin

    2011-05-01

    Previous studies have repeatedly demonstrated the impact of Gestalt structural grouping principles upon the parsing of motion correspondence in ambiguous apparent motion. Here, by embedding Chinese characters in a visual Ternus display that comprised two stimulus frames, we showed that the perception of visual apparent motion can be modulated by activation of task-irrelevant lexical representations. Each frame had two disks, with the second disk of the first frame and the first disk of the second frame being presented at the same location. Observers could perceive either "element motion," in which the endmost disk is seen as moving back and forth while the middle disk at the central position remains stationary, or "group motion," in which both disks appear to move laterally as a whole. More reports of group motion, as opposed to element motion, were obtained when the embedded characters formed two-character compound words than when they formed nonwords, although this lexicality effect appeared to be attenuated by the use of the same characters at the overlapping position across the two frames. Thus, grouping of visual elements in a changing world can be guided by both structural principles and prior world knowledge, including lexical information.

  2. A Cross-Age Study of Children's Knowledge of Apparent Celestial Motion

    ERIC Educational Resources Information Center

    Plummer, Julia D.

    2009-01-01

    The US National Science Education Standards and the Benchmarks for Science Literacy recommend that students understand the apparent patterns of motion of the Sun, Moon, and stars by the end of early elementary school, yet no research has specifically examined these concepts from an Earth-based perspective with this age group. This study examines…

  3. A Cross-Age Study of Children's Knowledge of Apparent Celestial Motion

    ERIC Educational Resources Information Center

    Plummer, Julia D.

    2009-01-01

    The US National Science Education Standards and the Benchmarks for Science Literacy recommend that students understand the apparent patterns of motion of the Sun, Moon, and stars by the end of early elementary school, yet no research has specifically examined these concepts from an Earth-based perspective with this age group. This study examines…

  4. Application of Powder Diffraction Methods to the Analysis of Short- and Long-Range Atomic Order in Nanocrystalline Diamond and SiC: The Concept of the Apparent Lattice Parameter (alp)

    NASA Technical Reports Server (NTRS)

    Palosz, B.; Grzanka, E.; Gierlotka, S.; Stelmakh, S.; Pielaszek, R.; Bismayer, U.; Weber, H.-P.; Palosz, W.

    2003-01-01

    Two methods of the analysis of powder diffraction patterns of diamond and SiC nanocrystals are presented: (a) examination of changes of the lattice parameters with diffraction vector Q ('apparent lattice parameter', alp) which refers to Bragg scattering, and (b), examination of changes of inter-atomic distances based on the analysis of the atomic Pair Distribution Function, PDF. Application of these methods was studied based on the theoretical diffraction patterns computed for models of nanocrystals having (i) a perfect crystal lattice, and (ii), a core-shell structure, i.e. constituting a two-phase system. The models are defined by the lattice parameter of the grain core, thickness of the surface shell, and the magnitude and distribution of the strain field in the shell. X-ray and neutron experimental diffraction data of nanocrystalline SiC and diamond powders of the grain diameter from 4 nm up to micrometers were used. The effects of the internal pressure and strain at the grain surface on the structure are discussed based on the experimentally determined dependence of the alp values on the Q-vector, and changes of the interatomic distances with the grain size determined experimentally by the atomic Pair Distribution Function (PDF) analysis. The experimental results lend a strong support to the concept of a two-phase, core and the surface shell structure of nanocrystalline diamond and SiC.

  5. Application of Powder Diffraction Methods to the Analysis of Short- and Long-Range Atomic Order in Nanocrystalline Diamond and SiC: The Concept of the Apparent Lattice Parameter (alp)

    NASA Technical Reports Server (NTRS)

    Palosz, B.; Grzanka, E.; Gierlotka, S.; Stelmakh, S.; Pielaszek, R.; Bismayer, U.; Weber, H.-P.; Palosz, W.

    2003-01-01

    Two methods of the analysis of powder diffraction patterns of diamond and SiC nanocrystals are presented: (a) examination of changes of the lattice parameters with diffraction vector Q ('apparent lattice parameter', alp) which refers to Bragg scattering, and (b), examination of changes of inter-atomic distances based on the analysis of the atomic Pair Distribution Function, PDF. Application of these methods was studied based on the theoretical diffraction patterns computed for models of nanocrystals having (i) a perfect crystal lattice, and (ii), a core-shell structure, i.e. constituting a two-phase system. The models are defined by the lattice parameter of the grain core, thickness of the surface shell, and the magnitude and distribution of the strain field in the shell. X-ray and neutron experimental diffraction data of nanocrystalline SiC and diamond powders of the grain diameter from 4 nm up to micrometers were used. The effects of the internal pressure and strain at the grain surface on the structure are discussed based on the experimentally determined dependence of the alp values on the Q-vector, and changes of the interatomic distances with the grain size determined experimentally by the atomic Pair Distribution Function (PDF) analysis. The experimental results lend a strong support to the concept of a two-phase, core and the surface shell structure of nanocrystalline diamond and SiC.

  6. Apparent diffusive motion of centrin foci in living cells: implications for diffusion-based motion in centriole duplication

    NASA Astrophysics Data System (ADS)

    Rafelski, Susanne M.; Keller, Lani C.; Alberts, Jonathan B.; Marshall, Wallace F.

    2011-04-01

    The degree to which diffusion contributes to positioning cellular structures is an open question. Here we investigate the question of whether diffusive motion of centrin granules would allow them to interact with the mother centriole. The role of centrin granules in centriole duplication remains unclear, but some proposed functions of these granules, for example, in providing pre-assembled centriole subunits, or by acting as unstable 'pre-centrioles' that need to be captured by the mother centriole (La Terra et al 2005 J. Cell Biol. 168 713-22), require the centrin foci to reach the mother. To test whether diffusive motion could permit such interactions in the necessary time scale, we measured the motion of centrin-containing foci in living human U2OS cells. We found that these centrin foci display apparently diffusive undirected motion. Using the apparent diffusion constant obtained from these measurements, we calculated the time scale required for diffusion to capture by the mother centrioles and found that it would greatly exceed the time available in the cell cycle. We conclude that mechanisms invoking centrin foci capture by the mother, whether as a pre-centriole or as a source of components to support later assembly, would require a form of directed motility of centrin foci that has not yet been observed.

  7. Apparent diffusive motion of centrin foci in living cells: implications for diffusion-based motion in centriole duplication.

    PubMed

    Rafelski, Susanne M; Keller, Lani C; Alberts, Jonathan B; Marshall, Wallace F

    2011-04-01

    The degree to which diffusion contributes to positioning cellular structures is an open question. Here we investigate the question of whether diffusive motion of centrin granules would allow them to interact with the mother centriole. The role of centrin granules in centriole duplication remains unclear, but some proposed functions of these granules, for example, in providing pre-assembled centriole subunits, or by acting as unstable 'pre-centrioles' that need to be captured by the mother centriole (La Terra et al 2005 J. Cell Biol. 168 713-22), require the centrin foci to reach the mother. To test whether diffusive motion could permit such interactions in the necessary time scale, we measured the motion of centrin-containing foci in living human U2OS cells. We found that these centrin foci display apparently diffusive undirected motion. Using the apparent diffusion constant obtained from these measurements, we calculated the time scale required for diffusion to capture by the mother centrioles and found that it would greatly exceed the time available in the cell cycle. We conclude that mechanisms invoking centrin foci capture by the mother, whether as a pre-centriole or as a source of components to support later assembly, would require a form of directed motility of centrin foci that has not yet been observed.

  8. Apparent diffusive motion of centrin foci in living cells: implications for diffusion-based motion in centriole duplication

    PubMed Central

    Rafelski, Susanne M.; Keller, Lani C.; Alberts, Jonathan B.; Marshall, Wallace F.

    2011-01-01

    The degree to which diffusion contributes to positioning cellular structures is an open question. Here we investigate the question of whether diffusive motion of centrin granules would allow them to interact with the mother centriole. The role of centrin granules in centriole duplication remains unclear, but some proposed functions of these granules, for example in providing pre-assembled centriole subunits, or by acting as unstable “pre-centrioles” that need to be captured by the mother centriole (La Terra et al., 2005), require the centrin foci to reach the mother. To test whether diffusive motion could permit such interactions in the necessary time scale, we measured the motion of centrin-containing foci in living human U2OS cells. We found that these centrin foci display apparently diffusive undirected motion. Using the apparent diffusion constant obtained from these measurements, we calculated the time scale required for diffusion to capture by the mother centrioles and found that it would greatly exceed the time available in the cell cycle. We conclude that mechanisms invoking centrin foci capture by the mother, whether as a pre-centriole or as a source of components to support later assembly, would require a form of directed motility of centrin foci that has not yet been observed. PMID:21378439

  9. USAKA Long Range Planning Study

    DTIC Science & Technology

    1990-03-01

    ORGANIZATION ERIM (if applicable ) United States Army I Strategic Defense Command 6c ADDRESS ICty. State. and ZIP Code) 7b ADDRESS (City, State. and ZIP...IDENTIFICATION NUMBER ORGANIZATION (if applicable ) US Army Strategic Def.Com. CSSD-H-KT DASG60-89-C-0013 8c ADDRESS (City, State. and ZIP Code) 10...activities. These are natural applications for the high power long range, well situated radars located at Kwajalein. The objective of the study described

  10. Elastic network models capture the motions apparent within ensembles of RNA structures

    PubMed Central

    Zimmermann, Michael T.; Jernigan, Robert L.

    2014-01-01

    The role of structure and dynamics in mechanisms for RNA becomes increasingly important. Computational approaches using simple dynamics models have been successful at predicting the motions of proteins and are often applied to ribonucleo-protein complexes but have not been thoroughly tested for well-packed nucleic acid structures. In order to characterize a true set of motions, we investigate the apparent motions from 16 ensembles of experimentally determined RNA structures. These indicate a relatively limited set of motions that are captured by a small set of principal components (PCs). These limited motions closely resemble the motions computed from low frequency normal modes from elastic network models (ENMs), either at atomic or coarse-grained resolution. Various ENM model types, parameters, and structure representations are tested here against the experimental RNA structural ensembles, exposing differences between models for proteins and for folded RNAs. Differences in performance are seen, depending on the structure alignment algorithm used to generate PCs, modulating the apparent utility of ENMs but not significantly impacting their ability to generate functional motions. The loss of dynamical information upon coarse-graining is somewhat larger for RNAs than for globular proteins, indicating, perhaps, the lower cooperativity of the less densely packed RNA. However, the RNA structures show less sensitivity to the elastic network model parameters than do proteins. These findings further demonstrate the utility of ENMs and the appropriateness of their application to well-packed RNA-only structures, justifying their use for studying the dynamics of ribonucleo-proteins, such as the ribosome and regulatory RNAs. PMID:24759093

  11. Elastic network models capture the motions apparent within ensembles of RNA structures.

    PubMed

    Zimmermann, Michael T; Jernigan, Robert L

    2014-06-01

    The role of structure and dynamics in mechanisms for RNA becomes increasingly important. Computational approaches using simple dynamics models have been successful at predicting the motions of proteins and are often applied to ribonucleo-protein complexes but have not been thoroughly tested for well-packed nucleic acid structures. In order to characterize a true set of motions, we investigate the apparent motions from 16 ensembles of experimentally determined RNA structures. These indicate a relatively limited set of motions that are captured by a small set of principal components (PCs). These limited motions closely resemble the motions computed from low frequency normal modes from elastic network models (ENMs), either at atomic or coarse-grained resolution. Various ENM model types, parameters, and structure representations are tested here against the experimental RNA structural ensembles, exposing differences between models for proteins and for folded RNAs. Differences in performance are seen, depending on the structure alignment algorithm used to generate PCs, modulating the apparent utility of ENMs but not significantly impacting their ability to generate functional motions. The loss of dynamical information upon coarse-graining is somewhat larger for RNAs than for globular proteins, indicating, perhaps, the lower cooperativity of the less densely packed RNA. However, the RNA structures show less sensitivity to the elastic network model parameters than do proteins. These findings further demonstrate the utility of ENMs and the appropriateness of their application to well-packed RNA-only structures, justifying their use for studying the dynamics of ribonucleo-proteins, such as the ribosome and regulatory RNAs. © 2014 Zimmermann and Jernigan; Published by Cold Spring Harbor Laboratory Press for the RNA Society.

  12. Long-range electron transfer

    PubMed Central

    Gray, Harry B.; Winkler, Jay R.

    2005-01-01

    Recent investigations have shed much light on the nuclear and electronic factors that control the rates of long-range electron tunneling through molecules in aqueous and organic glasses as well as through bonds in donor–bridge–acceptor complexes. Couplings through covalent and hydrogen bonds are much stronger than those across van der Waals gaps, and these differences in coupling between bonded and nonbonded atoms account for the dependence of tunneling rates on the structure of the media between redox sites in Ru-modified proteins and protein–protein complexes. PMID:15738403

  13. Long range planning at NASA

    NASA Technical Reports Server (NTRS)

    Bekey, Ivan

    1987-01-01

    NASA's current plans for the U.S. space program are described. Consideration is given to the debate between manned or unmanned exploration of space, missions to the moon versus missions to Mars, and the exploration of space applications or science. NASA has created the Office of Policy and Planning and the Office of Exploration in order to improve the planning of future space activities. Long-range trends such as second-generation Shuttles, cargo launch vehicles with large capacity systems, an advanced Space Station, the use of robotics, closed cycle life support, health maintenance techniques, and the processing of extraterrestrial materials are considered.

  14. Apparent motion produces multiple deficits in visually guided smooth pursuit eye movements of monkeys.

    PubMed

    Churchland, M M; Lisberger, S G

    2000-07-01

    We used apparent motion targets to explore how degraded visual motion alters smooth pursuit eye movements. Apparent motion targets consisted of brief stationary flashes with a spatial separation (Deltax), temporal separation (Deltat), and apparent target velocity equal to Deltax/Deltat. Changes in pursuit initiation were readily observed when holding target velocity constant and increasing the flash separation. As flash separation increased, the first deficit observed was an increase in the latency to peak eye acceleration. Also seen was a paradoxical increase in initial eye acceleration. Further increases in the flash separation produced larger increases in latency and resulted in decreased eye acceleration. By varying target velocity, we were able to discern that the visual inputs driving pursuit initiation show both temporal and spatial limits. For target velocities above 4-8 degrees /s, deficits in the initiation of pursuit were seen when Deltax exceeded 0.2-0.5 degrees, even when Deltat was small. For target velocities below 4-8 degrees /s, deficits appeared when Deltat exceeded 32-64 ms, even when Deltax was small. Further experiments were designed to determine whether the spatial limit varied as retinal and extra-retinal factors changed. Varying the initial retinal position of the target for motion at 18 degrees /s revealed that the spatial limit increased as a function of retinal eccentricity. We then employed targets that increased velocity twice, once from fixation and again during pursuit. These experiments revealed that, as expected, the spatial limit is expressed in terms of the flash separation on the retina. The spatial limit is uninfluenced by either eye velocity or the absolute velocity of the target. These experiments also demonstrate that "initiation" deficits can be observed during ongoing pursuit, and are thus not deficits in initiation per se. We conclude that such deficits result from degradation of the retino-centric motion signals that

  15. The representation of moving 3-D objects in apparent motion perception.

    PubMed

    Hidaka, Souta; Kawachi, Yousuke; Gyoba, Jiro

    2009-08-01

    In the present research, we investigated the depth information contained in the representations of apparently moving 3-D objects. By conducting three experiments, we measured the magnitude of representational momentum (RM) as an index of the consistency of an object's representation. Experiment 1A revealed that RM magnitude was greater when shaded, convex, apparently moving objects shifted to a flat circle than when they shifted to a shaded, concave, hemisphere. The difference diminished when the apparently moving objects were concave hemispheres (Experiment 1B). Using luminance-polarized circles, Experiment 2 confirmed that these results were not due to the luminance information of shading. Experiment 3 demonstrated that RM magnitude was greater when convex apparently moving objects shifted to particular blurred convex hemispheres with low-pass filtering than when they shifted to concave hemispheres. These results suggest that the internal object's representation in apparent motion contains incomplete depth information intermediate between that of 2-D and 3-D objects, particularly with regard to convexity information with low-spatial-frequency components.

  16. From body form to biological motion: the apparent velocity of human movement biases subjective time.

    PubMed

    Orgs, Guido; Bestmann, Sven; Schuur, Friederike; Haggard, Patrick

    2011-06-01

    In two experiments, we investigated time perception during apparent biological motion. Pictures of initial, intermediate, and final positions of a single movement were presented, with interstimulus intervals that were constant within trials but varied across trials. Movement paths were manipulated by changing the sequential order of body postures. Increasing the path length produced an increase in perceived movement velocity. To produce an implicit measure of apparent movement dynamics, we also asked participants to judge the duration of a frame surrounding the stimuli. Longer paths with higher apparent movement velocity produced shorter perceived durations. This temporal bias was attenuated for nonbody (Experiment 1) and inverted-body (Experiment 2) control stimuli. As an explanation for these findings, we propose an automatic top-down mechanism of biological-motion perception that binds successive body postures into a continuous perception of movement. We show that this mechanism is associated with velocity-dependent temporal compression. Furthermore, this mechanism operates on-line, bridging the intervals between static stimuli, and is specific to configural processing of body form.

  17. Cortical dynamics and awareness state: an interpretation of observed interstimulus interval dependence in apparent motion

    NASA Astrophysics Data System (ADS)

    Englman, R.; Yahalom, A.

    In a recent paper on Cortical Dynamics, Francis and Grossberg raise the question how visual forms and motion information are integrated to generate a coherent percept of moving forms? In their investigation of illusory contours (which are, like Kanizsa squares, mental constructs rather than stimuli on the retina) they quantify the subjective impression of apparent motion between illusory contours that are formed by two subsequent stimuli with delay times of about 0.2 s (called the interstimulus interval ISI). The impression of apparent motion is due to a back referral of a later experience to an earlier time in the conscious representation. A model is developed which describes the state of awareness in the observer in terms of a time dependent Schroedinger equation to which a second order time derivative is added. This addition requires as boundary conditions the values of the solution both at the beginning and after the process. Satisfactory quantitative agreement is found between the results of the model and the experimental results.We recall that in the von Neumann interpretation of the collapse of the quantum mechanical wave-function, the collapse was associated with an observer’s awareness. Some questions of causality and determinism that arise from later-time boundary conditions are touched upon.

  18. ON THE CONNECTION OF THE APPARENT PROPER MOTION AND THE VLBI STRUCTURE OF COMPACT RADIO SOURCES

    SciTech Connect

    Moor, A.; Frey, S.; Lambert, S. B.; Bakos, J. E-mail: frey@sgo.fomi.hu E-mail: oleg.titov@ga.gov.au

    2011-06-15

    Many of the compact extragalactic radio sources that are used as fiducial points to define the celestial reference frame are known to have proper motions detectable with long-term geodetic/astrometric very long baseline interferometry (VLBI) measurements. These changes can be as high as several hundred microarcseconds per year for certain objects. When imaged with VLBI at milliarcsecond (mas) angular resolution, these sources (radio-loud active galactic nuclei) typically show structures dominated by a compact, often unresolved 'core' and a one-sided 'jet'. The positional instability of compact radio sources is believed to be connected with changes in their brightness distribution structure. For the first time, we test this assumption in a statistical sense on a large sample rather than on only individual objects. We investigate a sample of 62 radio sources for which reliable long-term time series of astrometric positions as well as detailed 8 GHz VLBI brightness distribution models are available. We compare the characteristic direction of their extended jet structure and the direction of their apparent proper motion. We present our data and analysis method, and conclude that there is indeed a correlation between the two characteristic directions. However, there are cases where the {approx}1-10 mas scale VLBI jet directions are significantly misaligned with respect to the apparent proper motion direction.

  19. Long range handheld thermal imager

    NASA Astrophysics Data System (ADS)

    Seibel, Edward; Struckhoff, Andrew; McDaniel, Robert; Shamai, Shlomo

    2006-05-01

    Today's warfighter requires a lightweight, high performance thermal imager for use in night and reduced visibility conditions. To fill this need, the United States Marine Corps issued requirements for a Thermal Binocular System (TBS) Long Range Thermal Imager (LRTI). The requirements dictated that the system be lightweight, but still have significant range capabilities and extended operating time on a single battery load. Kollsman, Inc. with our partner Electro-Optics Industries, Ltd. (ElOp) responded to this need with the CORAL - a third-generation, Military Off-the-Shelf (MOTS) product that required very little modification to fully meet the LRTI specification. This paper will discuss the LRTI, a successful result of size, weight and power (SWaP) tradeoffs made to ensure a lightweight, but high performance thermal imager.

  20. The sopite syndrome revisited: Drowsiness and mood changes during real or apparent motion

    NASA Astrophysics Data System (ADS)

    Lawson, B. D.; Mead, A. M.

    The sopite syndrome is a poorly understood response to motion. Drowsiness and mood changes are the primary characteristics of the syndrome. The sopite syndrome can exist in isolation from more apparent symptoms such as nausea, can last long; after nausea has subsided, and can debilitate some individuals. It is most likely a distinct syndrome from "regular" motion sickness or common fatigue, and is of potential concern in a variety of situations. The syndrome may be particularly hazardous in transportation settings where other performance challenges (e.g., sleep deprivation) are already present. It is also a potential concern in cases where illnesses such as sleep disorders or depression may interact with the syndrome and confuse diagnosis.

  1. On the systematics in apparent proper motions of radio sources observed by VLBI

    NASA Astrophysics Data System (ADS)

    Raposo-Pulido, V.; Lambert, S.; Capitaine, N.; Nilsson, T.; Heinkelmann, R.; Schuh, H.

    2015-08-01

    For about twenty years, several authors have been investigating the systematics in the apparent proper motions of radio source positions. In some cases, the theoretical work developed (Pyne et al., 1996) could not be assessed due to the few number of VLBI observations. In other cases, the effects attributed to apparent proper motion could not be related successfully because there were no significant evidences from a statistical point of view (MacMillan, 2005). In this work we provide considerations about the estimation of the coefficients of spherical harmonics, based on a three-step procedure used by Titov et al. (2011) and Titov and Lambert (2013). The early stage of this work has been to compare step by step the computations and estimation processes between the Calc/Solve (http://gemini.gsfc.nasa.gov/solve/) and VieVS software (Böhm et al., 2012). To achieve this, the results were analyzed and compared with the previous study done by Titov and Lambert (2013).

  2. Long-Range Neutron Detection

    SciTech Connect

    AJ Peurrung; DC Stromswold; RR Hansen; PL Reeder; DS Barnett

    1999-11-24

    A neutron detector designed for detecting neutron sources at distances of 50 to 100 m has been constructed and tested. This detector has a large surface area (1 m{sup 2}) to enhance detection efficiency, and it contains a collimator and shielding to achieve direction sensitivity and reduce background. An unusual feature of the detector is that it contains no added moderator, such as polyethylene, to moderate fast neutrons before they reach the {sup 3}He detector. As a result, the detector is sensitive mainly to thermal neutrons. The moderator-free design reduces the weight of the detector, making it more portable, and it also aids in achieving directional sensitivity and background reduction. Test results show that moderated fission-neutron sources of strength about 3 x 10{sup 5} n/s can be detected at a distance out to 70 m in a counting time of 1000 s. The best angular resolution of the detector is obtained at distances of 30 m or less. As the separation .distance between the source and detector increases, the contribution of scattered neutrons to the measured signal increases with a resultant decrease in the ability to detect the direction to a distant source. Applications for which the long-range detector appears to be suitable include detecting remote neutron sources (including sources in moving vehicles) and monitoring neutron storage vaults for the intrusion of humans and the effects they make on the detected neutron signal. Also, the detector can be used to measure waste for the presence of transuranic material in the presence of high gamma-ray background. A test with a neutron source (3 x 10{sup 5} n/s) in a vehicle showed that the detector could readily measure an increase in count rate at a distance of 10 m for vehicle speeds up to 35 mph (the highest speed tested). These results. indicate that the source should be detectable at this distance at speeds up to 55 mph.

  3. Long range orbital error estimation for applications satellites

    NASA Technical Reports Server (NTRS)

    Bonavito, N. L.; Foreman, J. C.

    1978-01-01

    A method of optimum orbital averaging was employed to study the long range accuracy potential of polar orbiting applications satellites. This approach involved the determination of the boundary conditions of one set of differential equations of motion by adjusting the initial conditions in a least square sense with the use of data generated by another set of differential equations of motion.

  4. Distinct Visual Evoked Potential Morphological Patterns for Apparent Motion Processing in School-Aged Children

    PubMed Central

    Campbell, Julia; Sharma, Anu

    2016-01-01

    Measures of visual cortical development in children demonstrate high variability and inconsistency throughout the literature. This is partly due to the specificity of the visual system in processing certain features. It may then be advantageous to activate multiple cortical pathways in order to observe maturation of coinciding networks. Visual stimuli eliciting the percept of apparent motion and shape change is designed to simultaneously activate both dorsal and ventral visual streams. However, research has shown that such stimuli also elicit variable visual evoked potential (VEP) morphology in children. The aim of this study was to describe developmental changes in VEPs, including morphological patterns, and underlying visual cortical generators, elicited by apparent motion and shape change in school-aged children. Forty-one typically developing children underwent high-density EEG recordings in response to a continuously morphing, radially modulated, circle-star grating. VEPs were then compared across the age groups of 5–7, 8–10, and 11–15 years according to latency and amplitude. Current density reconstructions (CDR) were performed on VEP data in order to observe activated cortical regions. It was found that two distinct VEP morphological patterns occurred in each age group. However, there were no major developmental differences between the age groups according to each pattern. CDR further demonstrated consistent visual generators across age and pattern. These results describe two novel VEP morphological patterns in typically developing children, but with similar underlying cortical sources. The importance of these morphological patterns is discussed in terms of future studies and the investigation of a relationship to visual cognitive performance. PMID:27445738

  5. Apparent Motion Suppresses Responses in Early Visual Cortex: A Population Code Model

    PubMed Central

    Van Humbeeck, Nathalie; Putzeys, Tom; Wagemans, Johan

    2016-01-01

    Two stimuli alternately presented at different locations can evoke a percept of a stimulus continuously moving between the two locations. The neural mechanism underlying this apparent motion (AM) is thought to be increased activation of primary visual cortex (V1) neurons tuned to locations along the AM path, although evidence remains inconclusive. AM masking, which refers to the reduced detectability of stimuli along the AM path, has been taken as evidence for AM-related V1 activation. AM-induced neural responses are thought to interfere with responses to physical stimuli along the path and as such impair the perception of these stimuli. However, AM masking can also be explained by predictive coding models, predicting that responses to stimuli presented on the AM path are suppressed when they match the spatio-temporal prediction of a stimulus moving along the path. In the present study, we find that AM has a distinct effect on the detection of target gratings, limiting the maximum performance at high contrast levels. This masking is strongest when the target orientation is identical to the orientation of the inducers. We developed a V1-like population code model of early visual processing, based on a standard contrast normalization model. We find that AM-related activation in early visual cortex is too small to either cause masking or to be perceived as motion. Our model instead predicts strong suppression of early sensory responses during AM, consistent with the theoretical framework of predictive coding. PMID:27783622

  6. Preliminary paleomagnetic results from Late Neoproterozoic intrusions in Quebec, Canada: Rapid apparent latitudinal motion of Laurentia

    NASA Astrophysics Data System (ADS)

    McCausland, P. J. A.; van der Voo, R. D.; Brandenburg, J. P.

    2003-04-01

    Three Latest Precambrian Laurentian rift-related syenitic intrusions have been sampled for paleomagnetic and Ar40/Ar39 geochronologic study, to clarify paleogeographic relations between Laurentia and other cratons during the opening of the Iapetus Ocean. The ca. 564 Ma Mont Rigaud and Chatham-Grenville stocks outcrop as 40 square km multiphase intrusions in and adjacent to the Late Neoproterozoic Ottawa-Bonnechere rift in western Quebec. The ca. 575 Ma Mutton Bay syenite is exposed excellently as a 200 square km ring complex in eastern Quebec along the north shore of the Gulf of St. Lawrence. Preliminary paleomagnetic results indicate that Laurentia was near the south pole during the emplacement of the Mutton Bay complex, but was at low-to-equatorial paleolatitudes during the intrusion of the Mont Rigaud stock. The apparent latitudinal pole-to-equator motion, if confirmed, is extremely rapid (about 80 cm/a) using published geochronological constraints. It is unlikely that such rapid motion would have been due to drift alone, but might mark a major true polar wander event or a shift to an unusually large non-dipole contribution to the Earth's geomagnetic field during the terminal Neoproterozoic.

  7. Apparent motion photometry: evaluation and reliability of a novel method for the measurement of macular pigment.

    PubMed

    Bartlett, Hannah; Eperjesi, Frank

    2011-05-01

    Macular pigment is thought to protect the macula against exposure to light and oxidative stress, both of which may play a role in the development of age-related macular degeneration. The aim was to clinically evaluate a novel cathode-ray-tube-based method for measurement of macular pigment optical density (MPOD) known as apparent motion photometry (AMP). The authors took repeat readings of MPOD centrally (0°) and at 3° eccentricity for 76 healthy subjects (mean (±SD) 26.5±13.2 years, range 18-74 years). The overall mean MPOD for the cohort was 0.50±0.24 at 0°, and 0.28±0.20 at 3° eccentricity; these values were significantly different (t=-8.905, p<0.001). The coefficients of repeatability were 0.60 and 0.48 for the 0 and 3° measurements respectively. The data suggest that when the same operator is taking repeated 0° AMP MPOD readings over time, only changes of more than 0.60 units can be classed as clinically significant. In other words, AMP is not suitable for monitoring changes in MPOD over time, as increases of this magnitude would not be expected, even in response to dietary modification or nutritional supplementation.

  8. Advanced Climate Analysis and Long Range Forecasting

    DTIC Science & Technology

    2014-09-30

    1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Advanced Climate Analysis and Long Range Forecasting...project is to improve the long range and climate support provided by the U.S. Naval Oceanography Enterprise (NOe) for planning, conducting, and...months, several seasons, several years). The primary transition focus is on improving the long range and climate support capabilities of the Fleet

  9. The Long-Range Impact of Television.

    ERIC Educational Resources Information Center

    Comstock, George

    Long range effects may be of three varieties: those which are observable in the immediate period subsequent to exposure but are long range because of their continuing repetitive accumulation with each exposure; those which represent the cumulative or delayed impact on individuals of exposure to television; or those which represent the immediate…

  10. Long Range Plan, 1997-2000.

    ERIC Educational Resources Information Center

    Pennsylvania Coll. of Technology, Williamsport. Office of Strategic Planning and Research.

    At Pennsylvania College of Technology (PCT), long range planning is used to define institutional philosophy and mission and determine strategies to make the best use of available resources and implement actions to fulfill institutional mission. This document presents PCT's long-range plan for 1997-2000 in three parts. The first part describes long…

  11. The Involvement of Centralized and Distributed Processes in Sub-second Time Interval Adaptation: An ERP Investigation of Apparent Motion.

    PubMed

    Kaya, Utku; Yildirim, Fazilet Zeynep; Kafaligonul, Hulusi

    2017-09-09

    Accumulating evidence suggests that the timing of brief stationary sounds affects visual motion perception. Recent studies have shown that auditory time interval can alter apparent motion perception not only through concurrent stimulation but also through brief adaptation. The adaptation aftereffects for auditory time intervals were found to be similar to those for visual time intervals, suggesting the involvement of a central timing mechanism. To understand the nature of cortical processes underlying such aftereffects, we adapted observers to different time intervals by using either brief sounds or visual flashes and examined the evoked activity to the subsequently presented visual apparent motion. Both auditory and visual time interval adaptation led to significant changes in the ERPs elicited by the apparent motion. However, the changes induced by each modality were in the opposite direction. Also, they mainly occurred in different time windows and clustered over distinct scalp sites. The effects of auditory time interval adaptation were centered over parietal and parieto-central electrodes while the visual adaptation effects were mostly over occipital and parieto-occipitial regions. Moreover, the changes were much more salient when sounds were used during the adaptation phase. Taken together, our findings within the context of visual motion point to auditory dominance in the temporal domain and highlight the distinct nature of the sensory processes involved in auditory and visual time interval adaptation. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  12. Long-range correlations in computer diskettes

    NASA Astrophysics Data System (ADS)

    Zebende, G. F.; de Oliveira, P. M. C.; Penna, T. J. P.

    1998-03-01

    We find that successive versions of the files stored on a personal computer diskette mimic the evolution mechanism claimed to be responsible for the long-range correlations observed in DNA sequences. Starting from uncorrelated random files, long-range correlations are gradually introduced by successive editing, corresponding to point mutations, insertions, and deletions. This system has the advantage (over DNA sequences) of allowing experiments.

  13. Long range electrostatic forces in ionic liquids.

    PubMed

    Gebbie, Matthew A; Smith, Alexander M; Dobbs, Howard A; Lee, Alpha A; Warr, Gregory G; Banquy, Xavier; Valtiner, Markus; Rutland, Mark W; Israelachvili, Jacob N; Perkin, Susan; Atkin, Rob

    2017-01-19

    Ionic liquids are pure salts that are liquid under ambient conditions. As liquids composed solely of ions, the scientific consensus has been that ionic liquids have exceedingly high ionic strengths and thus very short Debye screening lengths. However, several recent experiments from laboratories around the world have reported data for the approach of two surfaces separated by ionic liquids which revealed remarkable long range forces that appear to be electrostatic in origin. Evidence has accumulated demonstrating long range surface forces for several different combinations of ionic liquids and electrically charged surfaces, as well as for concentrated mixtures of inorganic salts in solvent. The original interpretation of these forces, that ionic liquids could be envisioned as "dilute electrolytes," was controversial, and the origin of long range forces in ionic liquids remains the subject of discussion. Here we seek to collate and examine the evidence for long range surface forces in ionic liquids, identify key outstanding questions, and explore possible mechanisms underlying the origin of these long range forces. Long range surface forces in ionic liquids and other highly concentrated electrolytes hold diverse implications from designing ionic liquids for energy storage applications to rationalizing electrostatic correlations in biological self-assembly.

  14. Optical measurements of long-range protein vibrations.

    PubMed

    Acbas, Gheorghe; Niessen, Katherine A; Snell, Edward H; Markelz, A G

    2014-01-01

    Protein biological function depends on structural flexibility and change. From cellular communication through membrane ion channels to oxygen uptake and delivery by haemoglobin, structural changes are critical. It has been suggested that vibrations that extend through the protein play a crucial role in controlling these structural changes. While nature may utilize such long-range vibrations for optimization of biological processes, bench-top characterization of these extended structural motions for engineered biochemistry has been elusive. Here we show the first optical observation of long-range protein vibrational modes. This is achieved by orientation-sensitive terahertz near-field microscopy measurements of chicken egg white lysozyme single crystals. Underdamped modes are found to exist for frequencies >10 cm(-1). The existence of these persisting motions indicates that damping and intermode coupling are weaker than previously assumed. The methodology developed permits protein engineering based on dynamical network optimization.

  15. Optical measurements of long-range protein vibrations

    NASA Astrophysics Data System (ADS)

    Acbas, Gheorghe; Niessen, Katherine A.; Snell, Edward H.; Markelz, A. G.

    2014-01-01

    Protein biological function depends on structural flexibility and change. From cellular communication through membrane ion channels to oxygen uptake and delivery by haemoglobin, structural changes are critical. It has been suggested that vibrations that extend through the protein play a crucial role in controlling these structural changes. While nature may utilize such long-range vibrations for optimization of biological processes, bench-top characterization of these extended structural motions for engineered biochemistry has been elusive. Here we show the first optical observation of long-range protein vibrational modes. This is achieved by orientation-sensitive terahertz near-field microscopy measurements of chicken egg white lysozyme single crystals. Underdamped modes are found to exist for frequencies >10 cm-1. The existence of these persisting motions indicates that damping and intermode coupling are weaker than previously assumed. The methodology developed permits protein engineering based on dynamical network optimization.

  16. An improved self-alignment method for strapdown inertial navigation system based on gravitational apparent motion and dual-vector.

    PubMed

    Liu, Xixiang; Zhao, Yu; Liu, Xianjun; Yang, Yan; Song, Qing; Liu, Zhipeng

    2014-12-01

    Analysis and simulation results indicate that two problems should be solved when the self-alignment method based on gravitational apparent motion and dual-vector can be used for Strapdown Inertial Navigation System. The first one is how to identify the apparent motion from accelerometer measurement containing random noise and the second is how to avoid the collinear problem between two vectors used in alignment solution. In this paper, a parameter identification and reconstruction algorithm is proposed to solve the first problem and simulation results indicate that proposed algorithm can identify apparent motion from accelerometer measurements effectively; and reconstruction algorithm based on current identified parameters for dual-vector is designed in detail to solve the second problem which can make full use of newest identification and avoid collinear problem completely. Simulation and turntable results show that the proposed alignment method can fulfill self-alignment in a swinging condition and the alignment accuracy can reach the theoretical values determined by the sensor precision.

  17. Estimating the apparent transverse relaxation time (R2*) from images with different contrasts (ESTATICS) reduces motion artifacts

    PubMed Central

    Weiskopf, Nikolaus; Callaghan, Martina F.; Josephs, Oliver; Lutti, Antoine; Mohammadi, Siawoosh

    2014-01-01

    Relaxation rates provide important information about tissue microstructure. Multi-parameter mapping (MPM) estimates multiple relaxation parameters from multi-echo FLASH acquisitions with different basic contrasts, i.e., proton density (PD), T1 or magnetization transfer (MT) weighting. Motion can particularly affect maps of the apparent transverse relaxation rate R2*, which are derived from the signal of PD-weighted images acquired at different echo times. To address the motion artifacts, we introduce ESTATICS, which robustly estimates R2* from images even when acquired with different basic contrasts. ESTATICS extends the fitted signal model to account for inherent contrast differences in the PDw, T1w and MTw images. The fit was implemented as a conventional ordinary least squares optimization and as a robust fit with a small or large confidence interval. These three different implementations of ESTATICS were tested on data affected by severe motion artifacts and data with no prominent motion artifacts as determined by visual assessment or fast optical motion tracking. ESTATICS improved the quality of the R2* maps and reduced the coefficient of variation for both types of data—with average reductions of 30% when severe motion artifacts were present. ESTATICS can be applied to any protocol comprised of multiple 2D/3D multi-echo FLASH acquisitions as used in the general research and clinical setting. PMID:25309307

  18. Photon assisted long-range tunneling

    SciTech Connect

    Gallego-Marcos, Fernando; Sánchez, Rafael; Platero, Gloria

    2015-03-21

    We analyze long-range transport through an ac driven triple quantum dot with a single electron. Resonant transitions between separated and detuned dots are mediated by the exchange of n photons with the time-dependent field. An effective model is proposed in terms of second order (cotunneling) processes which dominate the long-range transport between the edge quantum dots. The ac field renormalizes the inter dot hopping, modifying the level hybridization. It results in a non-trivial behavior of the current with the frequency and amplitude of the external ac field.

  19. Passive long range acousto-optic sensor

    NASA Astrophysics Data System (ADS)

    Slater, Dan

    2006-08-01

    Alexander Graham Bell's photophone of 1880 was a simple free space optical communication device that used the sun to illuminate a reflective acoustic diaphragm. A selenium photocell located 213 m (700 ft) away converted the acoustically modulated light beam back into sound. A variation of the photophone is presented here that uses naturally formed free space acousto-optic communications links to provide passive multichannel long range acoustic sensing. This system, called RAS (remote acoustic sensor), functions as a long range microphone with a demonstrated range in excess of 40 km (25 miles).

  20. Dual adaptation of apparent concomitant motion contingent on head rotation frequency

    NASA Technical Reports Server (NTRS)

    Post, R. B.; Welch, R. B.

    1998-01-01

    Perceived movement of a stationary visual stimulus during head motion was measured before and after adaptation intervals during which participants performed voluntary head oscillations while viewing a moving spot. During these intervals, participants viewed the spot stimulus moving alternately in the same direction as the head was moving during either .25- or 2.0-Hz oscillations, and then in the opposite direction as the head at the other of the two frequencies. Postadaptation measures indicated that the visual stimuli were perceived as stationary only if traveling in the same direction as that viewed during adaptation at the same frequency of head motion. Thus, opposite directions of spot motion were perceived as stationary following adaptation depending on head movement frequency. The results provide an example of the ability to establish dual (or "context-specific") adaptations to altered visual-vestibular feedback.

  1. How visual illusions illuminate complementary brain processes: illusory depth from brightness and apparent motion of illusory contours.

    PubMed

    Grossberg, Stephen

    2014-01-01

    Neural models of perception clarify how visual illusions arise from adaptive neural processes. Illusions also provide important insights into how adaptive neural processes work. This article focuses on two illusions that illustrate a fundamental property of global brain organization; namely, that advanced brains are organized into parallel cortical processing streams with computationally complementary properties. That is, in order to process certain combinations of properties, each cortical stream cannot process complementary properties. Interactions between these streams, across multiple processing stages, overcome their complementary deficiencies to compute effective representations of the world, and to thereby achieve the property of complementary consistency. The two illusions concern how illusory depth can vary with brightness, and how apparent motion of illusory contours can occur. Illusory depth from brightness arises from the complementary properties of boundary and surface processes, notably boundary completion and surface-filling in, within the parvocellular form processing cortical stream. This illusion depends upon how surface contour signals from the V2 thin stripes to the V2 interstripes ensure complementary consistency of a unified boundary/surface percept. Apparent motion of illusory contours arises from the complementary properties of form and motion processes across the parvocellular and magnocellular cortical processing streams. This illusion depends upon how illusory contours help to complete boundary representations for object recognition, how apparent motion signals can help to form continuous trajectories for target tracking and prediction, and how formotion interactions from V2-to-MT enable completed object representations to be continuously tracked even when they move behind intermittently occluding objects through time.

  2. How visual illusions illuminate complementary brain processes: illusory depth from brightness and apparent motion of illusory contours

    PubMed Central

    Grossberg, Stephen

    2014-01-01

    Neural models of perception clarify how visual illusions arise from adaptive neural processes. Illusions also provide important insights into how adaptive neural processes work. This article focuses on two illusions that illustrate a fundamental property of global brain organization; namely, that advanced brains are organized into parallel cortical processing streams with computationally complementary properties. That is, in order to process certain combinations of properties, each cortical stream cannot process complementary properties. Interactions between these streams, across multiple processing stages, overcome their complementary deficiencies to compute effective representations of the world, and to thereby achieve the property of complementary consistency. The two illusions concern how illusory depth can vary with brightness, and how apparent motion of illusory contours can occur. Illusory depth from brightness arises from the complementary properties of boundary and surface processes, notably boundary completion and surface-filling in, within the parvocellular form processing cortical stream. This illusion depends upon how surface contour signals from the V2 thin stripes to the V2 interstripes ensure complementary consistency of a unified boundary/surface percept. Apparent motion of illusory contours arises from the complementary properties of form and motion processes across the parvocellular and magnocellular cortical processing streams. This illusion depends upon how illusory contours help to complete boundary representations for object recognition, how apparent motion signals can help to form continuous trajectories for target tracking and prediction, and how formotion interactions from V2-to-MT enable completed object representations to be continuously tracked even when they move behind intermittently occluding objects through time. PMID:25389399

  3. Muskegon Community College Long-Range Plan.

    ERIC Educational Resources Information Center

    Turner, Peter M.; And Others

    Long-range planning assumptions and goals are presented for Muskegon Community College (MCC) as they were submitted by a committee of area citizens. After introductory material summarizing the committee's mandate and activities, the report discusses the fiscal, demographic, curricular, and administrative changes likely to affect MCC during the…

  4. Long Range Program for Georgia Public Libraries.

    ERIC Educational Resources Information Center

    Georgia State Dept of Education, Atlanta. Div. of Public Library Services.

    The development of each area of Georgia's long range plan required the identification of present and projected needs, the definition of objectives and action plans to meet those needs, establishment of periodic evaluation procedures, dissemination of information, coordination with all types of libraries and their programs, allocations of funds for…

  5. Long Range Planning and Organizational Performance

    ERIC Educational Resources Information Center

    Karger, Delmar W.; Malik, Zafar A.

    1975-01-01

    The cited research very clearly indicates that the top management of any profit-seeking organization is delinquent or grossly negligent if it does not engage in fully integrated long-range planning--at least this would seem to be true in the ordinary case. (Author)

  6. Resources and Long-Range Forecasts

    ERIC Educational Resources Information Center

    Smith, Waldo E.

    1973-01-01

    The author argues that forecasts of quick depletion of resources in the environment as a result of overpopulation and increased usage may not be free from error. Ignorance still exists in understanding the recovery mechanisms of nature. Long-range forecasts are likely to be wrong in such situations. (PS)

  7. Look Ahead: Long-Range Learning Plans

    ERIC Educational Resources Information Center

    Weinstein, Margery

    2010-01-01

    Faced with an unsteady economy and fluctuating learning needs, planning a learning strategy designed to last longer than the next six months can be a tall order. But a long-range learning plan can provide a road map for success. In this article, four companies (KPMG LLP, CarMax, DPR Construction, and EMC Corp.) describe their learning plans, and…

  8. Resources and Long-Range Forecasts

    ERIC Educational Resources Information Center

    Smith, Waldo E.

    1973-01-01

    The author argues that forecasts of quick depletion of resources in the environment as a result of overpopulation and increased usage may not be free from error. Ignorance still exists in understanding the recovery mechanisms of nature. Long-range forecasts are likely to be wrong in such situations. (PS)

  9. Lattice gas models with long range interactions

    NASA Astrophysics Data System (ADS)

    Aristoff, David; Zhu, Lingjiong

    2017-02-01

    We study microcanonical lattice gas models with long range interactions, including power law interactions. We rigorously obtain a variational principle for the entropy. In a one dimensional example, we find a first order phase transition by proving the entropy is non-differentiable along a certain curve.

  10. Look Ahead: Long-Range Learning Plans

    ERIC Educational Resources Information Center

    Weinstein, Margery

    2010-01-01

    Faced with an unsteady economy and fluctuating learning needs, planning a learning strategy designed to last longer than the next six months can be a tall order. But a long-range learning plan can provide a road map for success. In this article, four companies (KPMG LLP, CarMax, DPR Construction, and EMC Corp.) describe their learning plans, and…

  11. Discussion of long-range weather prediction

    SciTech Connect

    Canavan, G.H.

    1998-09-10

    A group of scientists at Los Alamos have held a series of discussions of the issues in and prospects for improvements in Long-range Weather Predictions Enabled by Proving of the Atmosphere at High Space-Time Resolution. The group contained the requisite skills for a full evaluation, although this report presents only an informal discussion of the main technical issues. The group discussed all aspects of the proposal, which are grouped below into the headings: (1) predictability; (2) sensors and satellites, (3) DIAL and atmospheric sensing; (4) localized transponders; and (5) summary and integration. Briefly, the group agreed that the relative paucity of observations of the state of the atmosphere severely inhibits the accuracy of weather forecasts, and any program that leads to a more dense and uniform observational network is welcome. As shown in Long-range Weather more dense and uniform observational network is welcome. As shown in Long-range Weather Predictions, the pay-back of accurate long-range forecasts should more than justify the expenditure associated with improved observations and forecast models required. The essential step is to show that the needed technologies are available for field test and space qualification.

  12. Effects of environmental context on temporal perception bias in apparent motion.

    PubMed

    Masuda, Tomohiro; Kimura, Atsushi; Dan, Ippeita; Wada, Yuji

    2011-08-01

    We investigated whether the directional effect on the kappa effect can be attributed to the directional anisotropy of retinotopical space or to the representation of forces provided by environmental contexts (e.g., gravity) in an observed event. We examined whether different contexts with similar directional changes (straight vs. reversed motion) influence the kappa effect in four experiments. The object's motion appeared to depict only forces under the natural laws of physics on a slope (Experiment 1) or on a horizontal plane (Experiment 2) in virtual 3D space. In Experiments 3 and 4, the motion appeared to be subjected to external or self-driving forces additionally influenced by internal forces on a slope (Experiment 3) or a horizontal plane (Experiment 4). The results demonstrated that the directional effect on the kappa effect was observed only in Experiment 1, and not in Experiments 2 and 3, while the kappa effect was preserved. Furthermore, not even the kappa effect was observed in the reversed motion of Experiment 4. The results of the present study suggest that the determining factor of direction in the kappa effect is not a simple anisotropy, but rather the context of observed events. Copyright © 2011 Elsevier Ltd. All rights reserved.

  13. Crossmodal Statistical Binding of Temporal Information and Stimuli Properties Recalibrates Perception of Visual Apparent Motion.

    PubMed

    Zhang, Yi; Chen, Lihan

    2016-01-01

    Recent studies of brain plasticity that pertain to time perception have shown that fast training of temporal discrimination in one modality, for example, the auditory modality, can improve performance of temporal discrimination in another modality, such as the visual modality. We here examined whether the perception of visual Ternus motion could be recalibrated through fast crossmodal statistical binding of temporal information and stimuli properties binding. We conducted two experiments, composed of three sessions each: pre-test, learning, and post-test. In both the pre-test and the post-test, participants classified the Ternus display as either "element motion" or "group motion." For the training session in Experiment 1, we constructed two types of temporal structures, in which two consecutively presented sound beeps were dominantly (80%) flanked by one leading visual Ternus frame and by one lagging visual Ternus frame (VAAV) or dominantly inserted by two Ternus visual frames (AVVA). Participants were required to respond which interval (auditory vs. visual) was longer. In Experiment 2, we presented only a single auditory-visual pair but with similar temporal configurations as in Experiment 1, and asked participants to perform an audio-visual temporal order judgment. The results of these two experiments support that statistical binding of temporal information and stimuli properties can quickly and selectively recalibrate the sensitivity of perceiving visual motion, according to the protocols of the specific bindings.

  14. Apparent motion of monocular stimuli in different depth planes with lateral head movements.

    PubMed

    Shimono, K; Tam, W J; Ono, H

    2007-04-01

    A stationary monocular stimulus appears to move concomitantly with lateral head movements when it is embedded in a stereogram representing two front-facing rectangular areas, one above the other at two different distances. In Experiment 1, we found that the extent of perceived motion of the monocular stimulus covaried with the amplitude of head movement and the disparity between the two rectangular areas (composed of random dots). In Experiment 2, we found that the extent of perceived motion of the monocular stimulus was reduced compared to that in Experiment 1 when the rectangular areas were defined only by an outline rather than by random dots. These results are discussed using the hypothesis that a monocular stimulus takes on features of the binocular surface area in which it is embedded and is perceived as though it were treated as a binocular stimulus with regards to its visual direction and visual depth.

  15. Crossmodal Statistical Binding of Temporal Information and Stimuli Properties Recalibrates Perception of Visual Apparent Motion

    PubMed Central

    Zhang, Yi; Chen, Lihan

    2016-01-01

    Recent studies of brain plasticity that pertain to time perception have shown that fast training of temporal discrimination in one modality, for example, the auditory modality, can improve performance of temporal discrimination in another modality, such as the visual modality. We here examined whether the perception of visual Ternus motion could be recalibrated through fast crossmodal statistical binding of temporal information and stimuli properties binding. We conducted two experiments, composed of three sessions each: pre-test, learning, and post-test. In both the pre-test and the post-test, participants classified the Ternus display as either “element motion” or “group motion.” For the training session in Experiment 1, we constructed two types of temporal structures, in which two consecutively presented sound beeps were dominantly (80%) flanked by one leading visual Ternus frame and by one lagging visual Ternus frame (VAAV) or dominantly inserted by two Ternus visual frames (AVVA). Participants were required to respond which interval (auditory vs. visual) was longer. In Experiment 2, we presented only a single auditory–visual pair but with similar temporal configurations as in Experiment 1, and asked participants to perform an audio–visual temporal order judgment. The results of these two experiments support that statistical binding of temporal information and stimuli properties can quickly and selectively recalibrate the sensitivity of perceiving visual motion, according to the protocols of the specific bindings. PMID:27065910

  16. WAVES AS THE SOURCE OF APPARENT TWISTING MOTIONS IN SUNSPOT PENUMBRAE

    SciTech Connect

    Bharti, L.; Cameron, R. H.; Hirzberger, J.; Solanki, S. K.; Rempel, M.

    2012-06-20

    The motion of dark striations across bright filaments in a sunspot penumbra has become an important new diagnostic of convective gas flows in penumbral filaments. The nature of these striations has, however, remained unclear. Here, we present an analysis of small-scale motions in penumbral filaments in both simulations and observations. The simulations, when viewed from above, show fine structure with dark lanes running outward from the dark core of the penumbral filaments. The dark lanes either occur preferentially on one side or alternate between both sides of the filament. We identify this fine structure with transverse (kink) oscillations of the filament, corresponding to a sideways swaying of the filament. These oscillations have periods in the range of 5-7 minutes and propagate outward and downward along the filament. Similar features are found in observed G-band intensity time series of penumbral filaments in a sunspot located near disk center obtained by the Broadband Filter Imager on board the Hinode. We also find that some filaments show dark striations moving to both sides of the filaments. Based on the agreement between simulations and observations we conclude that the motions of these striations are caused by transverse oscillations of the underlying bright filaments.

  17. Holographic thermalization with initial long range correlation

    DOE PAGES

    Lin, Shu

    2016-01-19

    Here, we studied the evolution of the Wightman correlator in a thermalizing state modeled by AdS3-Vaidya background. A prescription was given for calculating the Wightman correlator in coordinate space without using any approximation. For equal-time correlator , we obtained an enhancement factor v2 due to long range correlation present in the initial state. This was missed by previous studies based on geodesic approximation. Moreover, we found that the long range correlation in initial state does not lead to significant modification to thermalization time as compared to known results with generic initial state. We also studied the spatially integrated Wightman correlatormore » and showed evidence on the distinction between long distance and small momentum physics for an out-of-equilibrium state. We also calculated the radiation spectrum of particles weakly coupled to O and found that lower frequency mode approaches thermal spectrum faster than high frequency mode.« less

  18. Long-range correlations in nucleotide sequences

    NASA Astrophysics Data System (ADS)

    Peng, C.-K.; Buldyrev, S. V.; Goldberger, A. L.; Havlin, S.; Sciortino, F.; Simons, M.; Stanley, H. E.

    1992-03-01

    DNA SEQUENCES have been analysed using models, such as an it-step Markov chain, that incorporate the possibility of short-range nucleotide correlations1. We propose here a method for studying the stochastic properties of nucleotide sequences by constructing a 1:1 map of the nucleotide sequence onto a walk, which we term a 'DNA walk'. We then use the mapping to provide a quantitative measure of the correlation between nucleotides over long distances along the DNA chain. Thus we uncover in the nucleotide sequence a remarkably long-range power law correlation that implies a new scale-invariant property of DNA. We find such long-range correlations in intron-containing genes and in nontranscribed regulatory DNA sequences, but not in complementary DNA sequences or intron-less genes.

  19. Gemini: A long-range cargo transport

    NASA Technical Reports Server (NTRS)

    1994-01-01

    The proposed Gemini, a long-range cargo transport, is designed as a high capacity, dedicated cargo transporter of 8'x8'x20' inter-modal containers, and long-range design. These requirements will result in a design that is larger than any existing aircraft. Due to the size, a conventional configuration would result in an aircraft unable to operate economically at existing airports. It is necessary to design for a minimum possible empty weight, wingspan, and landing gear track. After considering both a single fuselage biplane and a double fuselage biplane configuration, the design team choose the double fuselage biplane configuration. Both of these configuration choices result in a reduced wing root bending moment and subsequently in substantial savings in the wing weight. An overall decrease in the weight of the airplane, its systems, and fuel will be a direct result of the wing weight savings.

  20. Long-range correlations in nucleotide sequences

    NASA Technical Reports Server (NTRS)

    Peng, C. K.; Buldyrev, S. V.; Goldberger, A. L.; Havlin, S.; Sciortino, F.; Simons, M.; Stanley, H. E.

    1992-01-01

    DNA sequences have been analysed using models, such as an n-step Markov chain, that incorporate the possibility of short-range nucleotide correlations. We propose here a method for studying the stochastic properties of nucleotide sequences by constructing a 1:1 map of the nucleotide sequence onto a walk, which we term a 'DNA walk'. We then use the mapping to provide a quantitative measure of the correlation between nucleotides over long distances along the DNA chain. Thus we uncover in the nucleotide sequence a remarkably long-range power law correlation that implies a new scale-invariant property of DNA. We find such long-range correlations in intron-containing genes and in nontranscribed regulatory DNA sequences, but not in complementary DNA sequences or intron-less genes.

  1. Long-range correlations in nucleotide sequences

    NASA Technical Reports Server (NTRS)

    Peng, C. K.; Buldyrev, S. V.; Goldberger, A. L.; Havlin, S.; Sciortino, F.; Simons, M.; Stanley, H. E.

    1992-01-01

    DNA sequences have been analysed using models, such as an n-step Markov chain, that incorporate the possibility of short-range nucleotide correlations. We propose here a method for studying the stochastic properties of nucleotide sequences by constructing a 1:1 map of the nucleotide sequence onto a walk, which we term a 'DNA walk'. We then use the mapping to provide a quantitative measure of the correlation between nucleotides over long distances along the DNA chain. Thus we uncover in the nucleotide sequence a remarkably long-range power law correlation that implies a new scale-invariant property of DNA. We find such long-range correlations in intron-containing genes and in nontranscribed regulatory DNA sequences, but not in complementary DNA sequences or intron-less genes.

  2. Long Range Acoustic Communication in Deep Water

    DTIC Science & Technology

    2014-09-30

    Acoustic communication at long range in the ocean is challenging due to the substantial propagation loss, multipath delay spread , and channel...20 Hz in the upward refracting Arctic acoustic channel. However, the seafloor topography in the region of the Chukchi Plateau is very uneven over...which the depth was 600 m and thus the seafloor affected every mode of the ACOUS signal except for mode 1 which was confined to the upper 200 m. In April

  3. Bottom Interaction in Long Range Acoustic Propagation

    DTIC Science & Technology

    2009-09-30

    model calculations (RR, RSR, RBR, SRBR ray paths and the mode-like finale region), 2) deep shadow zone arrivals arising from the spread of energy below...arrivals near 75Hz were observed on bottom-mounted hydrophones in the shadow zone well below the SOFAR channel. Dushaw et al (1999) note: "This...explain the energy in the shadow zones: 1) energy is scattered from internal waves and fine structure in the ocean, or 2) long range sound propagation

  4. The apsidal motion of the eccentric eclipsing binary DI Herculis - An apparent discrepancy with general relativity

    NASA Technical Reports Server (NTRS)

    Guinan, E. F.; Maloney, F. P.

    1985-01-01

    The apsidal motion of the eccentric eclipsing binary DI Herculis (HD 175227) is determined from an analysis of the available observations and eclipse timings from 1959 to 1984. Least squares solutions to the primary and secondary minima extending over an 84-yr interval yielded a small advance of periastron omega dot of 0.65 deg/100 yr + or - 0.18/100 yr. The observed advance of the periastron is about one seventh of the theoretical value of 4.27 deg/100 yr that is expected from the combined relativistic and classical effects. The discrepancy is about -3.62 deg/100 yr, or a magnitude of about 20 sigma. Classical mechanisms which explain the discrepancy are discussed, together with the possibility that there may be problems with general relativity itself.

  5. The apsidal motion of the eccentric eclipsing binary DI Herculis - An apparent discrepancy with general relativity

    NASA Technical Reports Server (NTRS)

    Guinan, E. F.; Maloney, F. P.

    1985-01-01

    The apsidal motion of the eccentric eclipsing binary DI Herculis (HD 175227) is determined from an analysis of the available observations and eclipse timings from 1959 to 1984. Least squares solutions to the primary and secondary minima extending over an 84-yr interval yielded a small advance of periastron omega dot of 0.65 deg/100 yr + or - 0.18/100 yr. The observed advance of the periastron is about one seventh of the theoretical value of 4.27 deg/100 yr that is expected from the combined relativistic and classical effects. The discrepancy is about -3.62 deg/100 yr, or a magnitude of about 20 sigma. Classical mechanisms which explain the discrepancy are discussed, together with the possibility that there may be problems with general relativity itself.

  6. Evidence for long-range spatiotemporal interactions in infant and adult visual cortex

    PubMed Central

    Norcia, Anthony M.; Pei, Francesca; Kohler, Peter J.

    2017-01-01

    The development of spatiotemporal interactions giving rise to classical receptive field properties has been well studied in animal models, but little is known about the development of putative nonclassical mechanisms in any species. Here we used visual evoked potentials to study the developmental status of spatiotemporal interactions for stimuli that were biased to engage long-range spatiotemporal integration mechanisms. We compared responses to widely spaced stimuli presented either in temporal succession or at the same time. The former configuration elicits a percept of apparent motion in adults but the latter does not. Component flash responses were summed to make a linear prediction (no spatiotemporal interaction) for comparison with the measured evoked responses to sequential or simultaneous flash conditions. In adults, linear summation of the separate flash responses measured with 40% contrast stimuli predicted sequential flash responses twice as large as those measured, indicating that the response measured under apparent motion conditions is subadditive. Simultaneous-flash responses at the same spatial separation were also subadditive, but substantially less so. The subadditivity in both cases could be modeled as a simple multiplicative gain term across all electrodes and time points. In infants aged 3–8 months, responses to the stimuli used in adults were similar to their linear predictions at 40%, but the responses measured at 80% contrast resembled the subadditive responses of the adults for both sequential and simultaneous flash conditions. We interpret the developmental data as indicating that adult-like long-range spatiotemporal interactions can be demonstrated by 3–8 months, once stimulus contrast is high enough. PMID:28622700

  7. APPARENT/SPURIOUS MULTIFRACTALITY OF DATA SAMPLED FROM FRACTIONAL BROWNIAN/LÉVY MOTIONS (Invited)

    NASA Astrophysics Data System (ADS)

    Neuman, S. P.

    2009-12-01

    Many earth and environmental variables appear to be self-affine (monofractal) or multifractal with spatial (or temporal) increments having exceedance probability tails that decay as powers of -α where 1 < α ≤ 2. The increments can often be characterized by zero-mean symmetric stable distributions with Lévy indices α, suggesting that the variables are samples from corresponding random fields (or processes) constituting fractional Lévy motions (fLm); when α = 2 the distribution is Gaussian and the field constitutes fractional Brownian motion (fBm). The literature considers self-affine and multifractal modes of scaling to be fundamentally different, the first arising from additive and the second from multiplicative random fields or processes. We demonstrate theoretically that data having finite support, sampled across a finite domain from one realization of an additive Gaussian field forming fBm, give rise to positive square (or absolute) increments which behave as if the field was multifractal when in fact it is monofractal. Sampling such data from fLm with 1 < α < 2 causes them to exhibit spurious multifractality. Many data that appear to scale in a qualitatively similar manner (e.g., experimental and simulated turbulent velocities, some simulated porous flow velocities, landscape elevations, rain intensities, river network area and width functions, river flow series, soil water storage and physical properties) have been considered in the literature to be multifractal. It may be worth checking how closely such variables would fit monofractal models of the kind considered in this talk quantitatively.

  8. Cross-correlation of long-range correlated series

    NASA Astrophysics Data System (ADS)

    Arianos, Sergio; Carbone, Anna

    2009-03-01

    A method for estimating the cross-correlation Cxy(τ) of long-range correlated series x(t) and y(t), at varying lags τ and scales n, is proposed. For fractional Brownian motions with Hurst exponents H1 and H2, the asymptotic expression for Cxy(τ) depends only on the lag τ (wide-sense stationarity) and scales as a power of n with exponent H1+H2 for \\tau \\rightarrow 0 . The method is illustrated on: (i) financial series, to show the leverage effect; (ii) genomic sequences, to estimate the correlations between structural parameters along the chromosomes.

  9. Long-range aircraft are in demand

    SciTech Connect

    Demeis, R.

    1991-05-01

    The overriding technological combinations that must be developed to provide for increased payload/long-range efficiency in commercial aircraft are discussed. The many requirements include: lighter structures, fuel efficiency, available engine thrust at optimum cruise altitude, and the relationship of lift, drag, and engine fuel efficiency to produce the greatest range when drag divided by speed is kept to a minimum. Attention is given to the various new ultra-high-bypass turbofans under development that approach the 100,000 lb thrust category with bypass ratios of better than 20/1.

  10. Long-range laser-illuminated imaging

    NASA Astrophysics Data System (ADS)

    Dayton, David C.; Browne, Stephen L.; Sandven, Steven C.; Gonglewski, John D.; Gallegos, Joe; Shilko, Michael L., Sr.

    2000-11-01

    We demonstrate the utility of laser illuminated imaging for clandestine night time surveillance from a simulated airborne platform at standoff ranges in excess 20 km. In order to reduce the necessary laser per pulse energy required for illumination at such long ranges, and to mitigate atmospheric turbulence effects on image resolution, we have investigated a unique multi-frame post-processing technique. It is shown that in the presence of atmospheric turbulence and coherent speckle effects, this approach can produce superior results to conventional scene flood illumination.

  11. Fan-less long range alpha detector

    DOEpatents

    MacArthur, D.W.; Bounds, J.A.

    1994-05-10

    A fan-less long range alpha detector is disclosed which operates by using an electrical field between a signal plane and the surface or substance to be monitored for air ions created by collisions with alpha radiation. Without a fan, the detector can operate without the possibility of spreading dust and potential contamination into the atmosphere. A guard plane between the signal plane and the electrically conductive enclosure and maintained at the same voltage as the signal plane, reduces leakage currents. The detector can easily monitor soil, or other solid or liquid surfaces. 2 figures.

  12. NASA's Long-range Technology Goals

    NASA Technical Reports Server (NTRS)

    1990-01-01

    This document is part of the Final Report performed under contract NASW-3864, titled "NASA's Long-Range Technology Goals". The objectives of the effort were: To identify technologies whose development falls within NASA's capability and purview, and which have high potential for leapfrog advances in the national industrial posture in the 2005-2010 era. To define which of these technologies can also enable quantum jumps in the national space program. To assess mechanisms of interaction between NASA and industry constituencies for realizing the leapfrog technologies. This Volume details the findings pertaining to the advanced space-enabling technologies.

  13. Fan-less long range alpha detector

    DOEpatents

    MacArthur, Duncan W.; Bounds, John A.

    1994-01-01

    A fan-less long range alpha detector which operates by using an electrical field between a signal plane and the surface or substance to be monitored for air ions created by collisions with alpha radiation. Without a fan, the detector can operate without the possibility of spreading dust and potential contamination into the atmosphere. A guard plane between the signal plane and the electrically conductive enclosure and maintained at the same voltage as the signal plane, reduces leakage currents. The detector can easily monitor soil, or other solid or liquid surfaces.

  14. A criterion autoscheduler for long range planning

    NASA Technical Reports Server (NTRS)

    Sponsler, Jeffrey L.

    1994-01-01

    A constraint-based scheduling system called SPIKE is used to create long-term schedules for the Hubble Space Telescope. A meta-level scheduler called the Criterion Autoscheduler for Long range planning (CASL) was created to guide SPIKE's schedule generation according to the agenda of the planning scientists. It is proposed that sufficient flexibility exists in a schedule to allow high level planning heuristics to be applied without adversely affected crucial constraints such as spacecraft efficiency. This hypothesis is supported by test data which is described.

  15. Long Range Interactions in Nanoscale Science

    SciTech Connect

    French, Roger H; Parsegian, V Adrian; Podgonik, Rudolph; Rajter, Rick; Jagota, Anand; Luo, Jian; Asthagiri, Dilip; Chaudhury, Manoj; Chiang, Yet-Ming; Granick, Steve; Kalinin, Sergei V; Kardar, Mehran; Kjellander, Roland; Langreth, David C.; Lewis, Jennifer; Lustig, Steve; Wesolowski, David J; Wettlaufer, John; Ching, Wai-Yim; Finnis, Mike; Houlihan, Frank; Von Lilienfeld, O. Anatole; Van Oss, Carel; Zemb, Thomas

    2010-01-01

    Our understanding of the long range electrodynamic, electrostatic, and polar interactions that dominate the organization of small objects at separations beyond an interatomic bond length is reviewed. From this basic-forces perspective, a large number of systems are described from which one can learn about these organizing forces and how to modulate them. The many practical systems that harness these nanoscale forces are then surveyed. The survey reveals not only the promise of new devices and materials, but also the possibility of designing them more effectively.

  16. POSSIBLE DETECTION OF APPARENT SUPERLUMINAL INWARD MOTION IN MARKARIAN 421 AFTER THE GIANT X-RAY FLARE IN 2010 FEBRUARY

    SciTech Connect

    Niinuma, K.; Kino, M.; Oyama, T.; Nagai, H.; Isobe, N.; Gabanyi, K. E.; Hada, K.; Koyama, S.; Asada, K.; Fujisawa, K.

    2012-11-10

    We report on the very long baseline interferometry (VLBI) follow-up observations using the Japanese VLBI Network array at 22 GHz for the largest X-ray flare of TeV blazar Mrk 421 that occurred in 2010 mid-February. The total of five epochs of observations were performed at intervals of about 20 days between 2010 March 7 and May 31. No newborn component associated with the flare was seen directly in the total intensity images obtained by our multi-epoch VLBI observations. However, one jet component located at {approx}1 mas northwest from the core was able to be identified, and its proper motion can be measured as -1.66 {+-} 0.46 mas yr{sup -1}, which corresponds to an apparent velocity of -3.48 {+-} 0.97c. Here, this negative velocity indicates that the jet component was apparently moving toward the core. As the most plausible explanation, we discuss that the apparent negative velocity was possibly caused by the ejection of a new component, which could not be resolved with our observations. In this case, the obtained Doppler factor of the new component is around 10-20, which is consistent with the ones typically estimated by model fittings of spectral energy distribution for this source.

  17. Perception of visual apparent motion is modulated by a gap within concurrent auditory glides, even when it is illusory

    PubMed Central

    Wang, Qingcui; Guo, Lu; Bao, Ming; Chen, Lihan

    2015-01-01

    Auditory and visual events often happen concurrently, and how they group together can have a strong effect on what is perceived. We investigated whether/how intra- or cross-modal temporal grouping influenced the perceptual decision of otherwise ambiguous visual apparent motion. To achieve this, we juxtaposed auditory gap transfer illusion with visual Ternus display. The Ternus display involves a multi-element stimulus that can induce either of two different percepts of apparent motion: ‘element motion’ (EM) or ‘group motion’ (GM). In “EM,” the endmost disk is seen as moving back and forth while the middle disk at the central position remains stationary; while in “GM,” both disks appear to move laterally as a whole. The gap transfer illusion refers to the illusory subjective transfer of a short gap (around 100 ms) from the long glide to the short continuous glide when the two glides intercede at the temporal middle point. In our experiments, observers were required to make a perceptual discrimination of Ternus motion in the presence of concurrent auditory glides (with or without a gap inside). Results showed that a gap within a short glide imposed a remarkable effect on separating visual events, and led to a dominant perception of GM as well. The auditory configuration with gap transfer illusion triggered the same auditory capture effect. Further investigations showed that visual interval which coincided with the gap interval (50–230 ms) in the long glide was perceived to be shorter than that within both the short glide and the ‘gap-transfer’ auditory configurations in the same physical intervals (gaps). The results indicated that auditory temporal perceptual grouping takes priority over the cross-modal interaction in determining the final readout of the visual perception, and the mechanism of selective attention on auditory events also plays a role. PMID:26042055

  18. Paleomagnetic Euler Poles and the Apparent Polar Wander and Absolute Motion of North America Since the Carboniferous

    NASA Astrophysics Data System (ADS)

    Gordon, Richard G.; Cox, Allan; O'Hare, Scott

    1984-10-01

    The apparent polar wander path for a plate is determined from paleomagnetic data by plotting a time sequence of paleomagnetic poles, each representing the location of the earth's spin axis as seen from the plate. Apparent polar wander paths consist of long, gently curved segments termed tracks linked by short segments with sharp curvature termed cusps. The tracks correspond to time intervals when the direction of plate motion was constant, and the cusps correspond to time intervals when the direction of plate motion was changing. Apparent polar wander tracks, like hot spot tracks, tend to lie along small circles. The center of a circle is called a hot spot Euler pole in the case of hot spot tracks and a paleomagnetic Euler pole in the case of paleomagnetic apparent polar wander paths. Both types of tracks mark the motion of a plate with respect to a point, a rising mantle plume in the case of hot spot tracks and the earth's paleomagnetic axis in the case of apparent polar wander paths. Unlike approaches uced in previous studies, paleomagnetic Euler pole analysis yields all three components of motion—including the east-west motion—of a plate with respect to the paleomagnetic axis. A new method for analyzing paleomagnetic poles along a track by using a maximum likelihood criterion gives the best fit paleomagnetic Euler pole and an ellipsoid of 95% confidence about the paleomagnetic Euler pole. In analyzing synthetic and real data, we found that the ellipsoids are elongate, the long axes being aligned with a great circle drawn from the paleomagnetic Euler pole to the center of the apparent polar wander track. This elongation is caused by the azimuths of circular tracks being better defined than their radii of curvature. A Jurassic-Cretaceous paleomagnetic Euler pole for North America was determined from 13 paleomagnetic poles. This track begins with the Wingate and Kayenta formations (about 200 Ma) and ends with the Niobrara Formation (about 87 Ma). Morgan's hot

  19. Holographic thermalization with initial long range correlation

    SciTech Connect

    Lin, Shu

    2016-01-19

    Here, we studied the evolution of the Wightman correlator in a thermalizing state modeled by AdS3-Vaidya background. A prescription was given for calculating the Wightman correlator in coordinate space without using any approximation. For equal-time correlator , we obtained an enhancement factor v2 due to long range correlation present in the initial state. This was missed by previous studies based on geodesic approximation. Moreover, we found that the long range correlation in initial state does not lead to significant modification to thermalization time as compared to known results with generic initial state. We also studied the spatially integrated Wightman correlator and showed evidence on the distinction between long distance and small momentum physics for an out-of-equilibrium state. We also calculated the radiation spectrum of particles weakly coupled to O and found that lower frequency mode approaches thermal spectrum faster than high frequency mode.

  20. Long-range Order in Canary Song

    PubMed Central

    Markowitz, Jeffrey E.; Ivie, Elizabeth; Kligler, Laura; Gardner, Timothy J.

    2013-01-01

    Bird songs range in form from the simple notes of a Chipping Sparrow to the rich performance of the nightingale. Non-adjacent correlations can be found in the syntax of some birdsongs, indicating that the choice of what to sing next is determined not only by the current syllable, but also by previous syllables sung. Here we examine the song of the domesticated canary, a complex singer whose song consists of syllables, grouped into phrases that are arranged in flexible sequences. Phrases are defined by a fundamental time-scale that is independent of the underlying syllable duration. We show that the ordering of phrases is governed by long-range rules: the choice of what phrase to sing next in a given context depends on the history of the song, and for some syllables, highly specific rules produce correlations in song over timescales of up to ten seconds. The neural basis of these long-range correlations may provide insight into how complex behaviors are assembled from more elementary, stereotyped modules. PMID:23658509

  1. Long-range order in canary song.

    PubMed

    Markowitz, Jeffrey E; Ivie, Elizabeth; Kligler, Laura; Gardner, Timothy J

    2013-01-01

    Bird songs range in form from the simple notes of a Chipping Sparrow to the rich performance of the nightingale. Non-adjacent correlations can be found in the syntax of some birdsongs, indicating that the choice of what to sing next is determined not only by the current syllable, but also by previous syllables sung. Here we examine the song of the domesticated canary, a complex singer whose song consists of syllables, grouped into phrases that are arranged in flexible sequences. Phrases are defined by a fundamental time-scale that is independent of the underlying syllable duration. We show that the ordering of phrases is governed by long-range rules: the choice of what phrase to sing next in a given context depends on the history of the song, and for some syllables, highly specific rules produce correlations in song over timescales of up to ten seconds. The neural basis of these long-range correlations may provide insight into how complex behaviors are assembled from more elementary, stereotyped modules.

  2. Long Range Surface Plasmon Fluorescence Spectroscopy

    NASA Astrophysics Data System (ADS)

    Kasry, Amal; Knoll, Wolfgang

    2007-03-01

    Surface plasmon modes, excited at the two sides of a thin metal layer surrounded by two (nearly) identical dielectric media interact via the overlap of their electromagnetic fields. This overlap results in two new-coupled modes, a short and a long-range surface plasmon (LRSP). We demonstrate that combining the LRSP optics with fluorescence spectroscopy can result in a huge enhancement of the fluorescence signal due to the enhanced optical field of the LRSP at the metal dielectric interface, and to its increased evanescent depth into the analyte. This was demonstrated for the detection of the fluorescence intensity of chromophore labeled protein bound to the surface sensor. Beside that, some fundamentals were studied leading to some interesting difference between SPFS and LRSPFS.

  3. Long range inductive power transfer system

    NASA Astrophysics Data System (ADS)

    Lawson, James; Pinuela, Manuel; Yates, David C.; Lucyszyn, Stepan; Mitcheson, Paul D.

    2013-12-01

    We report upon a recently developed long range inductive power transfer system (IPT) designed to power remote sensors with mW level power consumption at distances up to 7 m. In this paper an inductive link is established between a large planar (1 × 1 m) transmit coil (Tx) and a small planer (170 × 170 mm) receiver coil (Rx), demonstrating the viability of highly asymmetrical coil configurations that real-world applications such as sensor networks impose. High Q factor Tx and Rx coils required for viable power transfer efficiencies over such distances are measured using a resonant method. The applicability of the Class-E amplifier in very low magnetic coupling scenarios and at the high frequencies of operation required for high Q operation is demonstrated by its usage as the Tx coil driver.

  4. Long-range polarimetric imaging through fog.

    PubMed

    Fade, Julien; Panigrahi, Swapnesh; Carré, Anthony; Frein, Ludovic; Hamel, Cyril; Bretenaker, Fabien; Ramachandran, Hema; Alouini, Mehdi

    2014-06-20

    We report an experimental implementation of long-range polarimetric imaging through fog over kilometric distance in real field atmospheric conditions. An incoherent polarized light source settled on a telecommunication tower is imaged at a distance of 1.3 km with a snapshot polarimetric camera including a birefringent Wollaston prism, allowing simultaneous acquisition of two images along orthogonal polarization directions. From a large number of acquisitions datasets and under various environmental conditions (clear sky/fog/haze, day/night), we compare the efficiency of using polarized light for source contrast increase with different signal representations (intensity, polarimetric difference, polarimetric contrast, etc.). With the limited-dynamics detector used, a maximum fourfold increase in contrast was demonstrated under bright background illumination using polarimetric difference image.

  5. Percolation with long-range correlated disorder.

    PubMed

    Schrenk, K J; Posé, N; Kranz, J J; van Kessenich, L V M; Araújo, N A M; Herrmann, H J

    2013-11-01

    Long-range power-law correlated percolation is investigated using Monte Carlo simulations. We obtain several static and dynamic critical exponents as functions of the Hurst exponent H, which characterizes the degree of spatial correlation among the occupation of sites. In particular, we study the fractal dimension of the largest cluster and the scaling behavior of the second moment of the cluster size distribution, as well as the complete and accessible perimeters of the largest cluster. Concerning the inner structure and transport properties of the largest cluster, we analyze its shortest path, backbone, red sites, and conductivity. Finally, bridge site growth is also considered. We propose expressions for the functional dependence of the critical exponents on H.

  6. Fe-based long range ordered alloys

    DOEpatents

    Liu, Chain T; Inouye, Henry; Schaffhauser, Anthony C.

    1980-01-01

    Malleable long range ordered alloys having high critical ordering temperatures exist in the V(Co,Fe).sub.3 and V(Co,Fe,Ni).sub.3 system having the composition comprising by weight 22-23% V, 35-50% Fe, 0-22% Co and 19-40% Ni with an electron density no greater than 8.00. Excellent high temperature properties occur in alloys having compositions comprising by weight 22-23% V, 35-45% Fe, 0-10% Co, 25-35% Ni; 22-23% V, 28-33% Ni and the remainder Fe; and 22-23% V, 19-22% Ni, 19-22% Co and the remainder Fe. The alloys are fabricable by casting, deforming and annealing for sufficient time to provide ordered structure.

  7. Fe-based long range ordered alloys

    DOEpatents

    Liu, C.T.

    Malleable long range ordered alloys with high critical ordering temperatures exist in the V(Co,Fe)/sub 3/ and V(Co,Fe,Ni)/sub 3/ system. The composition comprising by weight 22 to 23% V, 35 to 50% Fe, 0 to 22% Co and 19 to 40% Ni with an electron density no greater than 8.00. Excellent high temperature properties occur in alloys having compositions comprising by weight 22 to 23% V, 35 to 45% Fe, 0 to 10% Co, 25 to 35% Ni; 22 to 23% V, 28 to 33% Ni and the remainder Fe; and 22 to 23% V, 19 to 22% Co and the remainder Fe. The alloys are fabricable by casting, deforming and annealing for sufficient time to provide ordered structure.

  8. A Long-Range Video Observation Post

    SciTech Connect

    Arlowe, D.

    1995-07-01

    The Long Range Video Observation Post (LRVOP) Project is a cooperative effort between the US and a Middle Eastern country to develop an improved version of their current video observation post. This project is part of a larger effort to cooperatively develop anti-terrorist technology. This particular equipment is required to facilitate the recording and identification of humans at a range of 1000 meters in day-light and 500 meters at night. The project objective was to take advantage of recent advances in camera technology, recorders, and image processing to provide an significant increase in performance with only a minimum increase in size, weight, and cost. The goal of the project was to convert the users general needs and desires into specific requirements that could be bid on by several companies. This paper covers the specific performance requirements, generally describe the components that might be used, and concentrate on describing the more difficult issues and technical challenges.

  9. Long Range Planning at the Community College.

    ERIC Educational Resources Information Center

    Robertson-Smith, Mary Pat

    With the growing demands placed upon post-secondary institutions for a renewal and restructuring of values and priorities at a time when available resources are decreasing, the importance of planning becomes increasingly apparent. Strategic planning in particular, which deals with the mission, goals, values and resource allocation of the college,…

  10. The effect of burst duration, interstimulus onset interval, and loudspeaker arrangement on auditory apparent motion in the free field.

    PubMed

    Strybel, T Z; Neale, W

    1994-12-01

    The illusion of auditory apparent motion (AAM) was examined in order to determine the burst durations and interstimulus onset intervals (ISOIs) at which AAM is heard when spatial information regarding source location was varied. In the first experiment AAM was examined in the free field under monaural and binaural listening conditions. AAM was heard at the same burst duration-ISOI combinations for both listening conditions, but the location of the lead source could be determined only under binaural listening. In the second experiment AAM was measured with two and three sound sources. The number of sources did not affect the burst duration-ISOI combinations that produced AAM, but did affect the determination of the location of the lead source. In the third experiment AAM was tested when the sources were located in the median plane. The sources were located either at 0 degrees and 180 degrees azimuth, or both at 0 degrees azimuth, one in the horizontal plane and one 20 degrees above. The location of the speakers did not affect the timing requirements for the perception of AAM, only the timing requirements for the detection of the lead source. In the fourth experiment, AAM was measured when the vertical separation between the sources was either 2.5 degrees or 20 degrees. AAM was heard at both separations, even though 2.5 degrees is less than the vertical MAA. In each of these experiments only burst duration and ISOI determined whether motion was heard. Localization cues were important only for the determination of the direction of motion.

  11. Long Range, Coherent Synthetic Aperture Communications

    DTIC Science & Technology

    2009-09-30

    coupling of time and space in the presence of source motion. PUBLICATIONS 1. G.E. Edelmann , T. Akal, W.S. Hodgkiss, S. Kim, W.A. Kuperman, and H.C...communications in shallow water: Experimental demonstration at sea,” J. Acoust. Soc. Am. 118(4), 2365-2372, 2005 [published, refereed]. 3. G.F. Edelmann , H.C

  12. Long-Range Atlantic Acoustic Multipath Identification.

    NASA Astrophysics Data System (ADS)

    Legters, George Richard

    Multipath data from three long-range (900 kilometers) transmissions are examined. Two of the transmissions follow similar tracks, but are separated by the Gulf Stream at the receiving end. The third, which is substantially free of Gulf Stream influence, has been intensively studied Spiesberger et al. (J. Acoust. Soc. Am. 67, 2011-7 (1980)). A package of computer algorithms based on the geometrical optics approximation was developed to model and analyze the acoustic transmission. Path identification with ray calculations was attempted for the two transmission channels exhibiting stable multipath with success for the major features of the path structures. Excessive smoothing of the sound speed profile which eliminates the influence of the Atlantic eighteen-degree celsius water mass in the upper layers is shown to degrade the identification of early arrivals. The slight curvature of the ocean sound speed profile around four kilometers of depth also was critical to early arrival identification. The effect of weak range dependence was small while the effect of a gradual sloping bottom near one receiver was significant.

  13. Long range position and Orientation Tracking System

    SciTech Connect

    Armstrong, G.A.; Jansen, J.F.; Burks, B.L.

    1996-02-01

    The long range Position and Orientation Tracking System is an active triangulation-based system that is being developed to track a target to a resolution of 6.35 mm (0.25 in.) and 0.009{degrees}(32.4 arcseconds) over a range of 13.72 m (45 ft.). The system update rate is currently set at 20 Hz but can be increased to 100 Hz or more. The tracking is accomplished by sweeping two pairs of orthogonal line lasers over infrared (IR) sensors spaced with known geometry with respect to one another on the target (the target being a rigid body attached to either a remote vehicle or a remote manipulator arm). The synchronization and data acquisition electronics correlates the time that an IR sensor has been hit by one of the four lasers and the angle of the respective mirror at the time of the hit. This information is combined with the known geometry of the IR sensors on the target to determine position and orientation of the target. This method has the advantage of allowing the target to be momentarily lost due to occlusions and then reacquired without having to return the target to a known reference point. The system also contains a camera with operator controlled lighting in each pod that allows the target to be continuously viewed from either pod, assuming their are no occlusions.

  14. Long Range Infrared Surveillance System (LRIRSS)

    NASA Astrophysics Data System (ADS)

    Garcia, Gregg W.

    1987-09-01

    The contract requirement for the LRIRSS program was to design, fabricate, test, and deliver infrared (IR) surveillance systems capable of target detection and recognition at extended ranges. Several significant technical advancements were made during the course of the program. The twenty three inch primary reflecting surface had to be of aluminum due to thermal and weight considerations. This was accomplished through the use of diamond point turned aluminum. The IR and laser receivers are active simultaneously; this has been achieved through the incorporation of a "chopping" mirror that time shares the main aperture between the FLIR and CO2 laser receivers. In addition, the laser had to be eye-safe at the transmitter exit aperture. The use of a single pulse Carbon Dioxide (CO2) laser has met the requirement, and is certified by the US Army Environmental Hygiene Agency in Study No. 25-42-0335-85. The major technical challenges have been met, as well as several minor difficulties that arose during the execution of the effort. All hardware has been delivered to the Government in accord with the contractual schedule. NOMENCLATURE CO2 Carbon Dioxide CPU Central Processing Unit FLIR Forward Looking Infrared FOV Field of View IFOV Instantaneous Field of View IR Infrared LRF Laser Rangefinder LRIRSS Long Range Infrared Surveillance System PCB Printed Circuit Board

  15. A Long-Range Precision Ranging System

    NASA Technical Reports Server (NTRS)

    Easterling, Mahlon

    1961-01-01

    A technique is presented that may be used for precision real-time continuous range measuring at long ranges. The technique uses a carrier that is phase modulated by a pseudo-random binary sequence. The characteristics of the sequence that make it acquirable are discussed. The general form of a receiver capable of tracking the carrier is given and is shown to be a kind of phase-locked loop. A two-loop system capable of tracking a pseudo-random sequence and its clock is given. The combination of the receiver and the sequence tracking system form a ranging receiver. The power division necessary between the carrier and the sidebands is shown to be determined by the noise bandwidths of the two tracking systems. The bandwidths necessary for tracking space probes and Earth satellites are given and some experiments in radar-tracking Earth satellites are described. Based on these experiments, estimates are made of the useful range of such a system in tracking space probes.

  16. Long range correlation in earthquake precursory signals

    NASA Astrophysics Data System (ADS)

    Chaudhuri, H.; Barman, C.; Iyengar, A. N. S.; Ghose, D.; Sen, P.; Sinha, B.

    2013-07-01

    Research on earthquake prediction has drawn serious attention of the geophysicist, geologist and investigators in different fields of science across the globe for many decades. Researchers around the world are actively working on recording pre-earthquake changes in non-seismic parameters through a variety of methods that include anomalous changes in geochemical parameters of the Earth's crust, geophysical properties of the lithosphere as well as ionosphere etc. Several works also have been done in India to detect earthquake precursor signals using geochemical and geophysical methods. However, very few works have been done so far in India in this field through the application of nonlinear techniques to the recorded geophysical and geochemical precursory signals for earthquakes. The present paper deals with a short review of the early works on geochemical precursors that have been carried out in India as yet. With a view to detect earthquake precursory signals by means of gas-geochemical method we developed a network of seismo-geochemical monitoring observatories in India in hot springs and mud volcano crater. In the last few years we detected several geochemical anomalies and those were observed prior to some major earthquakes that occurred within a radius of 1500 km from the test sites. In the present paper we have applied nonlinear techniques to the long term, real-time and natural data sets of radon-222 and associated gamma originated out of the terrestrial degassing process of the earth. The results reveal a clear signature of the long range correlation present in the geochemical time series. This approach appears to be a potential tool to explore intrinsic information hidden within the earthquake precursory signals.

  17. Long-range dismount activity classification: LODAC

    NASA Astrophysics Data System (ADS)

    Garagic, Denis; Peskoe, Jacob; Liu, Fang; Cuevas, Manuel; Freeman, Andrew M.; Rhodes, Bradley J.

    2014-06-01

    Continuous classification of dismount types (including gender, age, ethnicity) and their activities (such as walking, running) evolving over space and time is challenging. Limited sensor resolution (often exacerbated as a function of platform standoff distance) and clutter from shadows in dense target environments, unfavorable environmental conditions, and the normal properties of real data all contribute to the challenge. The unique and innovative aspect of our approach is a synthesis of multimodal signal processing with incremental non-parametric, hierarchical Bayesian machine learning methods to create a new kind of target classification architecture. This architecture is designed from the ground up to optimally exploit correlations among the multiple sensing modalities (multimodal data fusion) and rapidly and continuously learns (online self-tuning) patterns of distinct classes of dismounts given little a priori information. This increases classification performance in the presence of challenges posed by anti-access/area denial (A2/AD) sensing. To fuse multimodal features, Long-range Dismount Activity Classification (LODAC) develops a novel statistical information theoretic approach for multimodal data fusion that jointly models multimodal data (i.e., a probabilistic model for cross-modal signal generation) and discovers the critical cross-modal correlations by identifying components (features) with maximal mutual information (MI) which is efficiently estimated using non-parametric entropy models. LODAC develops a generic probabilistic pattern learning and classification framework based on a new class of hierarchical Bayesian learning algorithms for efficiently discovering recurring patterns (classes of dismounts) in multiple simultaneous time series (sensor modalities) at multiple levels of feature granularity.

  18. Bias Reduction and Filter Convergence for Long Range Stereo

    NASA Technical Reports Server (NTRS)

    Sibley, Gabe; Matthies, Larry; Sukhatme, Gaurav

    2005-01-01

    We are concerned here with improving long range stereo by filtering image sequences. Traditionally, measurement errors from stereo camera systems have been approximated as 3-D Gaussians, where the mean is derived by triangulation and the covariance by linearized error propagation. However, there are two problems that arise when filtering such 3-D measurements. First, stereo triangulation suffers from a range dependent statistical bias; when filtering this leads to over-estimating the true range. Second, filtering 3-D measurements derived via linearized error propagation leads to apparent filter divergence; the estimator is biased to under-estimate range. To address the first issue, we examine the statistical behavior of stereo triangulation and show how to remove the bias by series expansion. The solution to the second problem is to filter with image coordinates as measurements instead of triangulated 3-D coordinates.

  19. The Frontiers of Nuclear Science: A Long-Range Plan

    SciTech Connect

    None, None

    2007-12-01

    In a letter dated July 17, 2006, the Department of Energy’s (DOE) Office of Science for Nuclear Physics and the National Science Foundation’s (NSF) Mathematical and Physical Sciences Directorate charged the Nuclear Science Advisory Committee (NSAC) to “conduct a study of the opportunities and priorities for U.S. nuclear physics research and recommend a long range plan that will provide a framework for coordinated advancement of the nation’s nuclear science research programs over the next decade.” This request set in motion a bottom-up review and forward look by the nuclear science community. With input from this community-wide process, a 59 member working group, which included the present NSAC members, gathered at the beginning of May, 2007, to develop guidance on how to optimize the future research directions for the field based on the projected resources outlined in the charge letter from DOE and NSF. A new long range plan—The Frontiers of Nuclear Science—grew out of this meeting. For the last decade, the top priority for nuclear science has been to utilize the flagship facilities that were built with investments by the nation in the 1980s and 1990s. Research with these facilities has led to many significant new discoveries that have changed our understanding of the world in which we live. But new discoveries demand new facilities, and the successes cannot continue indefinitely without new investment.

  20. An analysis of foliage effects on long-range surveillance

    NASA Astrophysics Data System (ADS)

    Hogan, D. L.

    1980-04-01

    Visibility is one of the key factors in determining the outcome of battles. With the advent of long range, moving target, air to ground surveillance radars, the motion of both the observing platform and the target have added to the visibility problem, which heretofore was analyzed in terms of shielding. The interaction of such factors as the minimum detectable velocity of the target, the trajectories of the target and the airborne radar platform, and the terrain and foliage masking combine to control the amount of time which a target is observed in a given scenario. This report continues the work done on dynamic masking, compares the masking calculation with and without foliage on a typical super highway in New England, and finally examines the correlation between predicted and observed foliage and terrain masking. The work was done in connection with the test and evaluation of the Multiple Antenna Surveillance Radar (MASR), a scaled model of a long range moving target surveillance system. MASR operated at L-band with a beamwidth of approximately 4.5 deg. In typical flight operation it observed the target complex from a range of 25 to 40 km. The altitude was selected to give lookdown angles ranging from 3 deg to 6 deg.

  1. On the Long-Range Directed Polymer Model

    NASA Astrophysics Data System (ADS)

    Wei, Ran

    2016-10-01

    We study the long-range directed polymer model on Z in a random environment, where the underlying random walk lies in the domain of attraction of an α -stable process for some α in (0,2]. Similar to the more classic nearest-neighbor directed polymer model, as the inverse temperature β increases, the model undergoes a transition from a weak disorder regime to a strong disorder regime. We extend most of the important results known for the nearest-neighbor directed polymer model on Z^d to the long-range model on Z. More precisely, we show that in the entire weak disorder regime, the polymer satisfies an analogue of invariance principle, while in the so-called very strong disorder regime, the polymer end point distribution contains macroscopic atoms and under some mild conditions, the polymer has a super-α -stable motion. Furthermore, for α in (1,2], we show that the model is in the very strong disorder regime whenever β >0, and we give explicit bounds on the free energy.

  2. Fractional dynamics of systems with long-range interaction

    NASA Astrophysics Data System (ADS)

    Tarasov, Vasily E.; Zaslavsky, George M.

    2006-12-01

    We consider one-dimensional chain of coupled linear and nonlinear oscillators with long-range powerwise interaction defined by a term proportional to 1/∣ n - m∣ α+1 . Continuous medium equation for this system can be obtained in the so-called infrared limit when the wave number tends to zero. We construct a transform operator that maps the system of large number of ordinary differential equations of motion of the particles into a partial differential equation with the Riesz fractional derivative of order α, when 0 < α < 2. Few models of coupled oscillators are considered and their synchronized states and localized structures are discussed in details. Particularly, we discuss some solutions of time-dependent fractional Ginzburg-Landau (or nonlinear Schrodinger) equation.

  3. Global earthquake catalogs and long-range correlation of seismic activity (Invited)

    NASA Astrophysics Data System (ADS)

    Ogata, Y.

    2009-12-01

    In view of the long-term seismic activity in the world, homogeneity of a global catalog is indispensable. Lately, Engdahl and Villaseñor (2002) compiled a global earthquake catalog of magnitude (M)7.0 or larger during the last century (1900-1999). This catalog is based on the various existing catalogs such as Abe catalog (Abe, 1981, 1984; Abe and Noguchi, 1983a, b) for the world seismicity (1894-1980), its modified catalogs by Perez and Scholz (1984) and by Pacheco and Sykes (1992), and also the Harvard University catalog since 1975. However, the original surface wave magnitudes of Abe catalog were systematically changed by Perez and Scholz (1984) and Pacheco and Sykes (1992). They suspected inhomogeneity of the Abe catalog and claimed that the two seeming changes in the occurrence rate around 1922 and 1948 resulted from magnitude shifts for some instrumental-related reasons. They used a statistical test assuming that such a series of large earthquakes in the world should behave as the stationary Poisson process (uniform occurrences). It is obvious that their claim strongly depends on their a priori assumption of an independent or short-range dependence of earthquake occurrence. We question this assumption from the viewpoint of long-range dependence of seismicity. We make some statistical analyses of the spectrum, dispersion-time diagrams and R/S for estimating and testing of the long-range correlations. We also attempt to show the possibility that the apparent rate change in the global seismicity can be simulated by a certain long-range correlated process. Further, if we divide the globe into the two regions of high and low latitudes, for example, we have different shapes of the cumulative curves to each other, and the above mentioned apparent change-points disappear from the both regions. This suggests that the Abe catalog shows the genuine seismic activity rather than the artifact of the suspected magnitude shifts that should appear in any wide enough regions

  4. Equation of motion for the solvent polarization apparent charges in the polarizable continuum model: Application to time-dependent CI

    NASA Astrophysics Data System (ADS)

    Pipolo, Silvio; Corni, Stefano; Cammi, Roberto

    2017-02-01

    The dynamics of the electrons for a molecule in solution is coupled to the dynamics of its polarizable environment, i.e., the solvent. To theoretically investigate such electronic dynamics, we have recently developed equations of motion (EOM) for the apparent solvent polarization charges that generate the reaction field in the Polarizable Continuum Model (PCM) for solvation and we have coupled them to a real-time time-dependent density functional theory (RT TDDFT) description of the solute [S. Corni et al., J. Phys. Chem. A 119, 5405 (2014)]. Here we present an extension of the EOM-PCM approach to a Time-Dependent Configuration Interaction (TD CI) description of the solute dynamics, which is free from the qualitative artifacts of RT TDDFT in the adiabatic approximation. As tests of the developed approach, we investigate the solvent Debye relaxation after an electronic excitation of the solute obtained either by a π pulse of light or by assuming the idealized sudden promotion to the excited state. Moreover, we present EOM for the Onsager solvation model and we compare the results with PCM. The developed approach provides qualitatively correct real-time evolutions and is promising as a general tool to investigate the electron dynamics elicited by external electromagnetic fields for molecules in solution.

  5. An apparent-motion confound causes the negative exogenous cuing effect at SOAs with larger numbers of target locations.

    PubMed

    Chen, Peii; Mordkoff, J Toby

    2012-01-01

    Salient but irrelevant stimuli seem to cause an automatic orienting of covert attention, facilitating the detection of targets at the cued location for a brief period of time. However, this finding is highly dependent on the number of possible target locations, at least when the simple detection of targets is all that the task requires. Whereas small numbers of possible target locations (e.g., 2 or 3) produce the well-known advantage in response time for valid cue trials (i.e., a positive cuing effect), larger numbers of possible target locations (e.g., 6 or 8) produce a negative cuing effect. If not explained in terms of a nonattentional mechanism, this latter finding raises serious questions about the standard interpretation of positive cuing effects. The present experiment tested a particular nonattentional mechanism: that a confound between target presence and apparent motion, which occurs only on invalid cue trials, is responsible for negative cuing effect. We reduced or eliminated this confound by the use of a new type of catch trial and eliminated the negative cuing effect with large numbers of target locations.

  6. Long-Range Planning. School Districts Prepare for the Future.

    ERIC Educational Resources Information Center

    Hart, Thomas E.

    1988-01-01

    Long-range planning is becoming increasingly important for educators in today's rapidly changing society. This bulletin accordingly presents a step-by-step model for school districts to use in developing and successfully implementing a long-range plan. Chapter 1 introduces long-range planning and suggests ways of getting district personnel…

  7. Hepatocellular carcinoma: short-term reproducibility of apparent diffusion coefficient and intravoxel incoherent motion parameters at 3.0T.

    PubMed

    Kakite, Suguru; Dyvorne, Hadrien; Besa, Cecilia; Cooper, Nancy; Facciuto, Marcelo; Donnerhack, Claudia; Taouli, Bachir

    2015-01-01

    To evaluate short-term test-retest and interobserver reproducibility of IVIM (intravoxel incoherent motion) diffusion parameters and ADC (apparent diffusion coefficient) of hepatocellular carcinoma (HCC) and liver parenchyma at 3.0T. In this prospective Institutional Review Board (IRB)-approved study, 11 patients were scanned twice using a free-breathing single-shot echo-planar-imaging, diffusion-weighted imaging (DWI) sequence using 4 b values (b = 0, 50, 500, 1000 s/mm(2)) and IVIM DWI using 16 b values (0-800 s/mm(2)) at 3.0T. IVIM parameters (D: true diffusion coefficient, D*: pseudodiffusion coefficient, PF: perfusion fraction) and ADC (using 4 b and 16 b) were calculated. Short-term test-retest and interobserver reproducibility of IVIM parameters and ADC were assessed by measuring correlation coefficient, coefficient of variation (CV), and Bland-Altman limits of agreements (BA-LA). Fifteen HCCs were assessed in 10 patients. Reproducibility of IVIM metrics in HCC was poor for D* and PF (mean CV 60.6% and 37.3%, BA-LA: -161.6% to 135.3% and -66.2% to 101.0%, for D* and PF, respectively), good for D and ADC (CV 19.7% and <16%, BA-LA -57.4% to 36.3% and -38.2 to 34.1%, for D and ADC, respectively). Interobserver reproducibility was on the same order of test-retest reproducibility except for PF in HCC. Reproducibility of diffusion parameters was better in liver parenchyma compared to HCC. Poor reproducibility of D*/PF and good reproducibility for D/ADC were observed in HCC and liver parenchyma. These findings may have implications for trials using DWI in HCC. © 2014 Wiley Periodicals, Inc.

  8. Long-range correlation and market segmentation in bond market

    NASA Astrophysics Data System (ADS)

    Wang, Zhongxing; Yan, Yan; Chen, Xiaosong

    2017-09-01

    This paper investigates the long-range auto-correlations and cross-correlations in bond market. Based on Detrended Moving Average (DMA) method, empirical results present a clear evidence of long-range persistence that exists in one year scale. The degree of long-range correlation related to maturities has an upward tendency with a peak in short term. These findings confirm the expectations of fractal market hypothesis (FMH). Furthermore, we have developed a method based on a complex network to study the long-range cross-correlation structure and applied it to our data, and found a clear pattern of market segmentation in the long run. We also detected the nature of long-range correlation in the sub-period 2007-2012 and 2011-2016. The result from our research shows that long-range auto-correlations are decreasing in the recent years while long-range cross-correlations are strengthening.

  9. Tunable long range forces mediated by self-propelled colloidal hard spheres.

    PubMed

    Ni, Ran; Cohen Stuart, Martien A; Bolhuis, Peter G

    2015-01-09

    Using Brownian dynamics simulations, we systematically study the effective interaction between two parallel hard walls in a 2D suspension of self-propelled (active) colloidal hard spheres, and we find that the effective force between two hard walls can be tuned from a long range repulsion into a long range attraction by changing the density of active particles. At relatively high densities, the active hard spheres can form a dynamic crystalline bridge, which induces a strong oscillating long range dynamic wetting repulsion between the walls. With decreasing density, the dynamic bridge gradually breaks, and an intriguing long range dynamic depletion attraction arises. A similar effect occurs in a quasi-2D suspension of self-propelled colloidal hard spheres by changing the height of the confinement. Our results open up new possibilities to manipulate the motion and assembly of microscopic objects by using active matter.

  10. Tunable Long Range Forces Mediated by Self-Propelled Colloidal Hard Spheres

    NASA Astrophysics Data System (ADS)

    Ni, Ran; Cohen Stuart, Martien A.; Bolhuis, Peter G.

    2015-01-01

    Using Brownian dynamics simulations, we systematically study the effective interaction between two parallel hard walls in a 2D suspension of self-propelled (active) colloidal hard spheres, and we find that the effective force between two hard walls can be tuned from a long range repulsion into a long range attraction by changing the density of active particles. At relatively high densities, the active hard spheres can form a dynamic crystalline bridge, which induces a strong oscillating long range dynamic wetting repulsion between the walls. With decreasing density, the dynamic bridge gradually breaks, and an intriguing long range dynamic depletion attraction arises. A similar effect occurs in a quasi-2D suspension of self-propelled colloidal hard spheres by changing the height of the confinement. Our results open up new possibilities to manipulate the motion and assembly of microscopic objects by using active matter.

  11. Oklahoma Long-Range Program for Library Development for the Fiscal Years 1972 Through 1977.

    ERIC Educational Resources Information Center

    Oklahoma State Dept. of Libraries, Oklahoma City.

    The Oklahoma Long-Range plan sets forth the goals and objectives for library development based on identified needs. In some cases these needs are apparent and are based on actual statistics and standards, in others data is absent, incomplete or questionable. In the latter instance, useful data had to be obtained. The primary role of this document…

  12. Can We Trust Long-Range Weather Forecasts ?

    NASA Astrophysics Data System (ADS)

    Mailier, Pascal

    2010-05-01

    Long-range weather forecasts are widely used in key sectors of the economy, but too often their properties and limitations are not understood well enough. This poster reviews the characteristics, methods and reliability of long-range weather forecasts, making recommendations regarding their use and quality assessment. Despite their limited skill, long-range weather forecasts can still be a valuable tool for managing weather risk provided the necessary caution is exercised.

  13. Long Range Facilities Planning Plan Guide Lines. Volume 1

    DTIC Science & Technology

    1982-04-01

    Maritime Administration invited Richard M. Muther to address the group on the subject of long range facility planning. Atlanta, Georgia. by MARAD was...NASSCO submitted a contract proposal to MARAD for cost sharing the development of NASSCO’s Long Range Facility Plan. Richard M. Muther addressed...given from United States A week-long seminar sponsored to train facility planners shipyards in the Muther tech- niques of long range facility planning

  14. Long-range electron transfer in a model for DNA

    NASA Astrophysics Data System (ADS)

    Endres, R. G.; Cox, D. L.

    2001-03-01

    Long-range electron transfer (ET) between well separated donor (D) and acceptor (A) sites through quantum mechanical tunneling is essential to many biological processes like respiration, photosynthesis and possibly DNA repair and damage. We are investigating the distance dependence of the electronic transition matrix element H_DA and hence of the electron transfer rate in a model for DNA. Fluorescence quenching in DNA at D-A distances of 40 Åand more suggests ET with an unusually high decay length β-1 of order 10 Å (S.O.Kelley and J.K.Barton, in:Metal Ions in Biological Systems), A.Sigel and H.Sigel, Eds., Marcel Dekker, New York, Vol.36, 1999. Assuming strong electron interactions on the D complex and suitable energetics, this could be explained by formation of a many electron Kondo boundstate. We obtain H_DA from the splitting between the two lowest adiabatic electronic eigenenergies, which constitute the potential energy surfaces (PES) of the nuclear motion in lowest order Born-Oppenheimer approximation. The PES are constructed by coupling D and A to local breathing modes and by making a semi-analytical variational ansatz for the adiabatic eigenstates. The results from the PES are compared with results from the Mulliken-Hush algorithm.

  15. Directed long-range molecular migration energized by surface reaction

    NASA Astrophysics Data System (ADS)

    Harikumar, K. R.; Polanyi, John C.; Zabet-Khosousi, Amir; Czekala, Piotr; Lin, Haiping; Hofer, Werner A.

    2011-05-01

    The recoil of adsorbates away (desorption) and towards (reaction) surfaces is well known. Here, we describe the long-range recoil of adsorbates in the plane of a surface, and accordingly the novel phenomenon of reactions occurring at a substantial distance from the originating event. Three thermal and three electron-induced surface reactions are shown by scanning tunnelling microscopy to propel their physisorbed ethylenic products across the rough surface of Si(100) over a distance of up to 200 Å before an attachment reaction. The recoil energy in the ethylenic products comes from thermal exoergicity or from electronic excitation of chemisorbed alkenes. We propose that the mechanism of migration is a rolling motion, because the recoiling molecule overcomes raised surface obstacles. Electronic excitation of propene causes directional recoil and often end-to-end inversion, suggesting cartwheeling. Ab initio calculations of the halogenation and electron-induced reactions support a model in which asymmetric forces between the molecule and the surface induce rotation and therefore migration.

  16. Directed long-range molecular migration energized by surface reaction.

    PubMed

    Harikumar, K R; Polanyi, John C; Zabet-Khosousi, Amir; Czekala, Piotr; Lin, Haiping; Hofer, Werner A

    2011-05-01

    The recoil of adsorbates away (desorption) and towards (reaction) surfaces is well known. Here, we describe the long-range recoil of adsorbates in the plane of a surface, and accordingly the novel phenomenon of reactions occurring at a substantial distance from the originating event. Three thermal and three electron-induced surface reactions are shown by scanning tunnelling microscopy to propel their physisorbed ethylenic products across the rough surface of Si(100) over a distance of up to 200 Å before an attachment reaction. The recoil energy in the ethylenic products comes from thermal exoergicity or from electronic excitation of chemisorbed alkenes. We propose that the mechanism of migration is a rolling motion, because the recoiling molecule overcomes raised surface obstacles. Electronic excitation of propene causes directional recoil and often end-to-end inversion, suggesting cartwheeling. Ab initio calculations of the halogenation and electron-induced reactions support a model in which asymmetric forces between the molecule and the surface induce rotation and therefore migration.

  17. Dynamic simulation of concentrated macromolecular solutions with screened long-range hydrodynamic interactions: Algorithm and limitations

    PubMed Central

    Ando, Tadashi; Chow, Edmond; Skolnick, Jeffrey

    2013-01-01

    Hydrodynamic interactions exert a critical effect on the dynamics of macromolecules. As the concentration of macromolecules increases, by analogy to the behavior of semidilute polymer solutions or the flow in porous media, one might expect hydrodynamic screening to occur. Hydrodynamic screening would have implications both for the understanding of macromolecular dynamics as well as practical implications for the simulation of concentrated macromolecular solutions, e.g., in cells. Stokesian dynamics (SD) is one of the most accurate methods for simulating the motions of N particles suspended in a viscous fluid at low Reynolds number, in that it considers both far-field and near-field hydrodynamic interactions. This algorithm traditionally involves an O(N3) operation to compute Brownian forces at each time step, although asymptotically faster but more complex SD methods are now available. Motivated by the idea of hydrodynamic screening, the far-field part of the hydrodynamic matrix in SD may be approximated by a diagonal matrix, which is equivalent to assuming that long range hydrodynamic interactions are completely screened. This approximation allows sparse matrix methods to be used, which can reduce the apparent computational scaling to O(N). Previously there were several simulation studies using this approximation for monodisperse suspensions. Here, we employ newly designed preconditioned iterative methods for both the computation of Brownian forces and the solution of linear systems, and consider the validity of this approximation in polydisperse suspensions. We evaluate the accuracy of the diagonal approximation method using an intracellular-like suspension. The diffusivities of particles obtained with this approximation are close to those with the original method. However, this approximation underestimates intermolecular correlated motions, which is a trade-off between accuracy and computing efficiency. The new method makes it possible to perform large-scale and

  18. 76 FR 77300 - Alaska Federal Lands Long Range Transportation Plan

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-12

    ... Federal Highway Administration Alaska Federal Lands Long Range Transportation Plan AGENCY: Federal Highway.... SUMMARY: The Federal Highway Administration, along with the Bureau of Land Management, Fish and Wildlife... Lands Long Range Transportation Plans (LRTP) for public review and comment. The draft plans outline a...

  19. Long-range attraction in aqueous colloidal suspensions

    NASA Astrophysics Data System (ADS)

    Zhao, Qing; Coult, Jason; Pollack, Gerald H.

    2010-11-01

    Long-range attractions in aqueous suspensions were observed between polymeric microspheres and also between microspheres and a gel bead. Attractive displacements were consistently seen even between like-charged entities, and they were observed over spans as large as 2 mm. Such behaviors are unexpected, and may reside in a long-range attraction mechanism.

  20. Perceptual and Decisional Contributions to Audiovisual Interactions in the Perception of Apparent Motion: A Signal Detection Study

    ERIC Educational Resources Information Center

    Sanabria, Daniel; Spence, Charles; Soto-Faraco, Salvador

    2007-01-01

    Motion information available to different sensory modalities can interact at both perceptual and post-perceptual (i.e., decisional) stages of processing. However, to date, researchers have only been able to demonstrate the influence of one of these components at any given time, hence the relationship between them remains uncertain. We addressed…

  1. Long-range patterns in Hindmarsh-Rose networks

    NASA Astrophysics Data System (ADS)

    Etémé, Armand Sylvin; Tabi, Conrad Bertrand; Mohamadou, Alidou

    2017-02-01

    Long-range diffusive effects are included in a discrete Hindmarsh-Rose neural network. Their impact on the emergence of nonlinear patterns is investigated via the modulational instability. The whole system is first shown to fully reduce to a single nonlinear differential-difference equation, which has plane wave solutions. The stability of such solutions is investigated and regions of instability are found to be importantly influenced by long-range parameters. The analytical results are confirmed through direct numerical simulations, where scattered and chaotic patterns illustrate the long-range effect. Synchronized states are described by quasi-periodic patterns for nearest-neighbor coupling. The external stimulus is also shown to efficiently control strong long-range effects via more regular spatiotemporal patterns.

  2. Assessment of a long-range corrected hybrid functional

    SciTech Connect

    Vydrov, Oleg A.; Scuseria, Gustavo E.

    2006-12-21

    Common approximate exchange-correlation functionals suffer from self-interaction error, and as a result, their corresponding potentials have incorrect asymptotic behavior. The exact asymptote can be imposed by introducing range separation into the exchange component and replacing the long-range portion of the approximate exchange by the Hartree-Fock counterpart. The authors show that this long-range correction works particularly well in combination with the short-range variant of the Perdew-Burke-Ernzerhof (PBE) exchange functional. This long-range-corrected hybrid, here denoted LC-{omega}PBE, is remarkably accurate for a broad range of molecular properties, such as thermochemistry, barrier heights of chemical reactions, bond lengths, and most notably, description of processes involving long-range charge transfer.

  3. Generation of short and long range temporal correlated noise

    SciTech Connect

    Romero, A.H.; Sancho, J.M.

    1999-11-20

    The authors present the implementation of an algorithm to generate Gaussian random noises with prescribed time correlations that can be either long or short ranged. Examples of Langevin dynamics with short and long range noises are presented and discussed.

  4. Dynamics of Quantum Matter with Long-Range Entanglement

    DTIC Science & Technology

    2013-06-07

    REPORT Final Report: Dynamics of quantum matter with long-range entanglement. 14. ABSTRACT 16. SECURITY CLASSIFICATION OF: Recent experiments on...ultracold atoms in optical lattices have opened a remarkable new window on the dynamics of quantum matter with long-range entanglement. The simplest...paradigm of this is the boson superfluid-insulator quantum phase transition in two spatial dimensions. This project will study the theoretical

  5. Long-range eye tracking: A feasibility study

    SciTech Connect

    Jayaweera, S.K.; Lu, Shin-yee

    1994-08-24

    The design considerations for a long-range Purkinje effects based video tracking system using current technology is presented. Past work, current experiments, and future directions are thoroughly discussed, with an emphasis on digital signal processing techniques and obstacles. It has been determined that while a robust, efficient, long-range, and non-invasive eye tracking system will be difficult to develop, such as a project is indeed feasible.

  6. Long-range surface magnetoplasmons in thin nickel films

    NASA Astrophysics Data System (ADS)

    Hickernell, Robert K.; Sarid, Dror

    1987-08-01

    The results of a theoretical and experimental investigation of long-range surface magnetoplasmons in thin, magnetic metal films are presented. With a transversely applied magnetic field, the reflectance modulation measurements from prism-coupled modes in nickel films are in agreement with the theory. The reflectance modulation is the same order of magnitude for prism-coupled long-range and single-interface magnetoplasmons.

  7. Long-range rapidity correlations in hadron-nucleus interactions

    SciTech Connect

    Capella, A.; Tran Thanh Van, J.

    1984-06-01

    Long-range rapidity correlations between particles produced in proton-nucleus interactions at 200 GeV/c are studied in the multichain dual parton model. A large long-range correlation between particles produced in two rapidity intervals is predicted, provided these two rapidity intervals are properly chosen. The predicted effect is easily measurable. Predictions at 1 TeV are also given.

  8. Neural correlates of apparent motion perception of impoverished facial stimuli: A comparison of ERP and ERSP activity

    PubMed Central

    Kolchinsky, Artemy; Puce, Aina

    2014-01-01

    Our brains readily decode human movements, as shown by neural responses to face and body motion. N170 event-related potentials (ERPs) are earlier and larger to mouth opening movements relative to closing in both line-drawn and natural faces, and gaze aversions relative to direct gaze in natural faces (Puce and Perrett, 2003; Puce et al., 2000). Here we extended this work by recording both ERP and oscillatory EEG activity (event-related spectral perturbations, ERSPs) to line-drawn faces depicting eye and mouth movements (Eyes: Direct vs Away; Mouth: Closed vs Open) and non-face motion controls. Neural activity was measured in 2 occipitotemporal clusters of 9 electrodes, one in each hemisphere. Mouth opening generated larger N170s than mouth closing, replicating earlier work. Eye motion elicited robust N170s that did not differ between gaze conditions. Control condition differences were seen, and generated the largest N170. ERSP difference plots across conditions in the occipitotemporal electrode clusters (Eyes: Direct vs Away; Mouth: Closed vs Open) showed statistically significant differences in beta and gamma bands for gaze direction changes and mouth opening at similar post-stimulus times and frequencies. In contrast, control stimuli showed activity in the gamma band with a completely different time profile and hemispheric distribution to facial stimuli. ERSP plots were generated in two 9 electrode clusters centered on central sites, C3 and C4. In the left cluster for all stimulus conditions, broadband beta suppression persisted from about 250 ms post-motion onset. In the right cluster, beta suppression was seen for control conditions only. Statistically significant differences between conditions were confined between 4 – 15 Hz, unlike occipitotemporal sites where differences occurred at much higher frequencies (high beta/gamma). Our data indicate that N170 amplitude is sensitive to the amount of movement in the visual field, independent of stimulus type. In

  9. Spatio-temporal priority revisited: the role of feature identity and similarity for object correspondence in apparent motion.

    PubMed

    Hein, Elisabeth; Moore, Cathleen M

    2012-08-01

    We live in a dynamic environment in which objects change location over time. To maintain stable object representations the visual system must determine how newly sampled information relates to existing object representations, the correspondence problem. Spatiotemporal information is clearly an important factor that the visual system takes into account when solving the correspondence problem, but is feature information irrelevant as some theories suggest? The Ternus display provides a context in which to investigate solutions to the correspondence problem. Two sets of three horizontally aligned disks, shifted by one position, were presented in alternation. Depending on how correspondence is resolved, these displays are perceived either as one disk "jumping" from one end of the row to the other (element motion) or as a set of three disks shifting back and forth together (group motion). We manipulated a feature (e.g., color) of the disks such that, if features were taken into account by the correspondence process, it would bias the resolution of correspondence toward one version or the other. Features determined correspondence, whether they were luminance-defined or not. Moreover, correspondence could be established on the basis of similarity, when features were not identical between alternations. Finally, the stronger the feature information supported a certain correspondence solution the more it dominated spatiotemporal information.

  10. Long-Range Interactions Restrict Water Transport in Pyrophyllite Interlayers

    SciTech Connect

    Zarzycki, Piotr; Gilbert, Benjamin

    2016-04-27

    Water diffusion within smectite clay interlayers is reduced by confinement and hence is highly determined by the interlayer spacings that are adopted during swelling. However, a molecular understanding of the short-and long-range forces governing interlayer water structure and dynamics is lacking. Using molecular dynamics simulations of water intercalated between pyrophyllite (smectite prototype) layers we provide a detailed picture of the variation of interlayered water mobility accompanying smectite expansion. Subtle changes in hydrogen bond network structure cause significant changes in water mobility that is greater for stable hydration states and reduced for intermediate separations. By studying pyrophyllite with and without external water we reveal that long-range electrostatic forces apply a restraining effect upon interlayer water mobility. Our findings are relevant for broad range of confining nanostructures with walls thin enough to permit long-range interactions that could affect the mobility of confined solvent molecules and solute species.

  11. Long-range interactions in lattice field theory

    SciTech Connect

    Rabin, J.M.

    1981-06-01

    Lattice quantum field theories containing fermions can be formulated in a chirally invariant way provided long-range interactions are introduced. It is established that in weak-coupling perturbation theory such a lattice theory is renormalizable when the corresponding continuum theory is, and that the continuum theory is indeed recovered in the perturbative continuum limit. In the strong-coupling limit of these theories one is led to study an effective Hamiltonian describing a Heisenberg antiferromagnet with long-range interactions. Block-spin renormalization group methods are used to find a critical rate of falloff of the interactions, approximately as inverse distance squared, which separates a nearest-neighbor-antiferromagnetic phase from a phase displaying identifiable long-range effects. A duality-type symmetry is present in some block-spin calculations.

  12. Long-Range Interactions Restrict Water Transport in Pyrophyllite Interlayers

    NASA Astrophysics Data System (ADS)

    Zarzycki, Piotr; Gilbert, Benjamin

    2016-04-01

    Water diffusion within smectite clay interlayers is reduced by confinement and hence is highly determined by the interlayer spacings that are adopted during swelling. However, a molecular understanding of the short- and long-range forces governing interlayer water structure and dynamics is lacking. Using molecular dynamics simulations of water intercalated between pyrophyllite (smectite prototype) layers we provide a detailed picture of the variation of interlayered water mobility accompanying smectite expansion. Subtle changes in hydrogen bond network structure cause significant changes in water mobility that is greater for stable hydration states and reduced for intermediate separations. By studying pyrophyllite with and without external water we reveal that long-range electrostatic forces apply a restraining effect upon interlayer water mobility. Our findings are relevant for broad range of confining nanostructures with walls thin enough to permit long-range interactions that could affect the mobility of confined solvent molecules and solute species.

  13. Long-range oil and gas forecasting methodologies: literature survey

    SciTech Connect

    Cherniavsky, E.A.

    1980-08-01

    Performance of long-range energy system analyses requires the capability to project conventional domestic oil and gas supplies in the long term. The objective of the Long-range Forecasting Methodology project is to formulate an approach to this problem which will be compatible with the principal tool employed by the Energy Information Administration of the Department of Energy for long-range energy system analyses, the Long-term Energy Analysis Package (LEAP). This paper reports on projection methodologies that have appeared in the literature, evaluates them in terms of their applicability to the LEAP framework, and discusses the principal determinants of conventional domestic oil and gas supply in the long run.

  14. Long-Range Interactions Restrict Water Transport in Pyrophyllite Interlayers

    DOE PAGES

    Zarzycki, Piotr; Gilbert, Benjamin

    2016-04-27

    Water diffusion within smectite clay interlayers is reduced by confinement and hence is highly determined by the interlayer spacings that are adopted during swelling. However, a molecular understanding of the short-and long-range forces governing interlayer water structure and dynamics is lacking. Using molecular dynamics simulations of water intercalated between pyrophyllite (smectite prototype) layers we provide a detailed picture of the variation of interlayered water mobility accompanying smectite expansion. Subtle changes in hydrogen bond network structure cause significant changes in water mobility that is greater for stable hydration states and reduced for intermediate separations. By studying pyrophyllite with and without externalmore » water we reveal that long-range electrostatic forces apply a restraining effect upon interlayer water mobility. Our findings are relevant for broad range of confining nanostructures with walls thin enough to permit long-range interactions that could affect the mobility of confined solvent molecules and solute species.« less

  15. Application of advanced technology to future long-range aircraft

    NASA Technical Reports Server (NTRS)

    Schrader, O. E.

    1976-01-01

    The objective of this paper is to provide an overview assessment of three separate programs at Langley Research Center that have incorporated advanced technology into the design of long-range passenger and cargo aircraft. The first technology centers around the use of an span-loaded cargo aircraft with the payload distributed along the wing. This concept has the potential for reduced structural weights. The second technology is the application of laminar flow control (LFC) to the aircraft to reduce the aerodynamic drag. The use of LFC can reduce the fuel requirements during long-range cruise. The last program evaluates the production of alternate aircraft fuels from coal and the use of liquid hydrogen as an aircraft fuel. Coal-derived hydrogen as an aircraft fuel offers both the prospect for reduced dependence on petroleum fuels and improved performance for long-range aircraft.

  16. Long-Range Interactions Restrict Water Transport in Pyrophyllite Interlayers

    PubMed Central

    Zarzycki, Piotr; Gilbert, Benjamin

    2016-01-01

    Water diffusion within smectite clay interlayers is reduced by confinement and hence is highly determined by the interlayer spacings that are adopted during swelling. However, a molecular understanding of the short- and long-range forces governing interlayer water structure and dynamics is lacking. Using molecular dynamics simulations of water intercalated between pyrophyllite (smectite prototype) layers we provide a detailed picture of the variation of interlayered water mobility accompanying smectite expansion. Subtle changes in hydrogen bond network structure cause significant changes in water mobility that is greater for stable hydration states and reduced for intermediate separations. By studying pyrophyllite with and without external water we reveal that long-range electrostatic forces apply a restraining effect upon interlayer water mobility. Our findings are relevant for broad range of confining nanostructures with walls thin enough to permit long-range interactions that could affect the mobility of confined solvent molecules and solute species. PMID:27118164

  17. Long-range surface plasmons in electrode structures

    NASA Technical Reports Server (NTRS)

    Stegeman, G. I.; Burke, J. J.

    1983-01-01

    Surface polaritons guided by symmetric double metal film structures are analyzed, with particular attention given to the attenuation of the two long-range modes that occur. It is found that long-range surface plasmon polariton modes do exist for double electrode structures over a limited range of material parameters. Guided by thin metal electrodes, surface plasmon polaritons can achieve millimeter plus propagation distances in the near infrared. It is pointed out that if the slab is electrooptic, then very low voltages will be needed to manipulate the waves. The fact that long-range modes exist simultaneously with junction tunnel plasmons may be of use in providing directional radiation from light-emitting junctions or the inverse process of light to electrical energy conversion.

  18. Fourth International Symposium on Long-Range Sound Propagation

    NASA Technical Reports Server (NTRS)

    Willshire, William L., Jr. (Compiler)

    1990-01-01

    Long range sound propagation is an aspect of many acoustical problems ranging from en route aircraft noise to the acoustic detection of aircraft. Over the past decade, the University of Mississippi and the Open University of England, together with a third institution, have held a symposium approx. every 2 years so that experts in the field of long range propagation could exchange information on current research, identify areas needing additional work, and coordinate activities as much as possible. The Fourth International Symposium on Long Range Sound Propagation was jointly sponsored by the University of Mississippi, the Open University of England, and NASA. Papers were given in the following areas: ground effects on propagation; infrasound propagation; and meteorological effects on sound propagation. A compilation of the presentations made at the symposium is presented along with a list of attendees, and the agenda.

  19. Integrated thermal infrared imaging and structure-from-motion photogrammetry to map apparent temperature and radiant hydrothermal heat flux at Mammoth Mountain, CA, USA

    NASA Astrophysics Data System (ADS)

    Lewis, A.; Hilley, G. E.; Lewicki, J. L.

    2015-09-01

    This work presents a method to create high-resolution (cm-scale) orthorectified and georeferenced maps of apparent surface temperature and radiant hydrothermal heat flux and estimate the radiant hydrothermal heat emission rate from a study area. A ground-based thermal infrared (TIR) camera was used to collect (1) a set of overlapping and offset visible imagery around the study area during the daytime and (2) time series of co-located visible and TIR imagery at one or more sites within the study area from pre-dawn to daytime. Daytime visible imagery was processed using the structure-from-motion photogrammetric method to create a digital elevation model onto which pre-dawn TIR imagery was orthorectified and georeferenced. Three-dimensional maps of apparent surface temperature and radiant hydrothermal heat flux were then visualized and analyzed from various computer platforms (e.g., Google Earth, ArcGIS). We demonstrate this method at the Mammoth Mountain fumarole area on Mammoth Mountain, CA. Time-averaged apparent surface temperatures and radiant hydrothermal heat fluxes were observed up to 73.7 °C and 450 W m- 2, respectively, while the estimated radiant hydrothermal heat emission rate from the area was 1.54 kW. Results should provide a basis for monitoring potential volcanic unrest and mitigating hydrothermal heat-related hazards on the volcano.

  20. Integrated thermal infrared imaging and Structure-from-Motion photogrametry to map apparent temperature and radiant hydrothermal heat flux at Mammoth Mountain, CA USA

    USGS Publications Warehouse

    Lewis, Aaron; George Hilley,; Lewicki, Jennifer L.

    2015-01-01

    This work presents a method to create high-resolution (cm-scale) orthorectified and georeferenced maps of apparent surface temperature and radiant hydrothermal heat flux and estimate the radiant hydrothermal heat emission rate from a study area. A ground-based thermal infrared (TIR) camera was used to collect (1) a set of overlapping and offset visible imagery around the study area during the daytime and (2) time series of co-located visible and TIR imagery at one or more sites within the study area from pre-dawn to daytime. Daytime visible imagery was processed using the Structure-from-Motion photogrammetric method to create a digital elevation model onto which pre-dawn TIR imagery was orthorectified and georeferenced. Three-dimensional maps of apparent surface temperature and radiant hydrothermal heat flux were then visualized and analyzed from various computer platforms (e.g., Google Earth, ArcGIS). We demonstrate this method at the Mammoth Mountain fumarole area on Mammoth Mountain, CA. Time-averaged apparent surface temperatures and radiant hydrothermal heat fluxes were observed up to 73.7 oC and 450 W m-2, respectively, while the estimated radiant hydrothermal heat emission rate from the area was 1.54 kW. Results should provide a basis for monitoring potential volcanic unrest and mitigating hydrothermal heat-related hazards on the volcano.

  1. Design of a high capacity long range cargo aircraft

    NASA Technical Reports Server (NTRS)

    Weisshaar, Terrence A.

    1994-01-01

    This report examines the design of a long range cargo transport to attempt to reduce ton-mile shipping costs and to stimulate the air cargo market. This design effort involves the usual issues but must also include consideration of: airport terminal facilities; cargo loading and unloading; and defeating the 'square-cube' law to design large structures. This report reviews the long range transport design problem and several solutions developed by senior student design teams at Purdue University. The results show that it will be difficult to build large transports unless the infrastructure is changed and unless the basic form of the airplane changes so that aerodynamic and structural efficiencies are employed.

  2. Small long-range alpha detector (LRAD) with computer readout

    SciTech Connect

    MacArthur, D.W.; Allander, K.S.; Bounds, J.A.; Butterfield, K.B.

    1991-10-01

    The small long-range alpha detector developed by N-2 was described in detail in the Los Alamos publication LA-12073-MS, Long-Range Alpha Detector,'' published in 1991. Since publication of that report, a computerized data acquisition system has been added to the LRAD detector. In addition to detailing the new data acquisition system, we discuss new data generated with the enhanced system, including measurements of (1) ultimate sensitivity; (2) detector linearity; (3) ion lifetime; and (4) characteristics. Furthermore, we have expanded our understanding of ion recombination and statistical noise effects in the LRAD and have addressed them here as well as several proposed applications. 6 refs., 30 figs.

  3. Long-range correction for dipolar fluids at planar interfaces

    NASA Astrophysics Data System (ADS)

    Werth, Stephan; Horsch, Martin; Hasse, Hans

    2015-12-01

    A slab-based long-range correction for dipolar interactions in molecular dynamics simulation of systems with a planar geometry is presented and applied to simulate vapour-liquid interfaces. The present approach is validated with respect to the saturated liquid density and the surface tension of the Stockmayer fluid and a molecular model for ethylene oxide. The simulation results exhibit no dependence on the cut-off radius for radii down to 1 nm, proving that the long-range correction accurately captures the influence of the dipole moment on the intermolecular interaction energies and forces as well as the virial and the surface tension.

  4. Specific heat spectra of long-range correlated DNA molecules

    NASA Astrophysics Data System (ADS)

    Moreira, D. A.; Albuquerque, E. L.; Mauriz, P. W.; Vasconcelos, M. S.

    2006-11-01

    The specific heat spectra of long-range correlated DNA molecules is theoretically analyzed for a stacked array of single-stranded DNA made up from the nucleotides guanine G, adenine A, cytosine C and thymine T arranged in the Fibonacci and Rudin-Shapiro quasiperiodic sequences, with the aim to compare them with those related with a genomic DNA sequence. The energy spectra are calculated using the one-dimensional Schrödinger equation in a tight-binding approximation with the on-site energy exhibiting long-range disorder and nonrandom hopping amplitudes.

  5. Probabilistic approach to long range planning of manpower

    NASA Technical Reports Server (NTRS)

    Lejk, R. A.

    1967-01-01

    Publication presents a total long range planning model for project oriented organizations. The total model consists of planning systems which originate - /1/ at the project level and consolidate into an overall plan, and /2/ from a budetary ceiling and allocate to the individual projects. Analysis of /1/ and /2/ is provided for management decision making.

  6. Air Force B-21 Long Range Strike Bomber

    DTIC Science & Technology

    2016-04-14

    Congressional Research Service 7 Industrial Base Northrop Grumman intends to build the B-21 at its facilities at Air Force Plant 42 in Palmdale, CA, which were...DefenseNews.com, March 2, 2016. 32 A useful discussion of these issues can be found in Andrew Hunter , “Long Range Strike: 3 Lessons from Defense

  7. Strategic Long Range Planning for Universities. AIR Forum 1980 Paper.

    ERIC Educational Resources Information Center

    Baker, Michael E.

    The use of strategic long-range planning at Carnegie-Mellon University (CMU) is discussed. A structure for strategic planning analysis that integrates existing techniques is presented, and examples of planning activities at CMU are included. The key concept in strategic planning is competitive advantage: if a university has a competitive…

  8. Long Range Planning Model. Management for Effective Teaching.

    ERIC Educational Resources Information Center

    Fairfax County Public Schools, VA. Dept. of Instructional Services.

    The Management for Effective Teaching (MET) Long Range Planning Model has been developed to provide practical assistance in planning for classroom management and teaching. The planning procedures were devised to help elementary teachers in the Fairfax County (Virginia) Public Schools implement the school system's Program of Studies. In the model…

  9. Long Range Development Plan, University of California, Riverside.

    ERIC Educational Resources Information Center

    Russell (George Vernon) and Associates, Architects and Planners.

    A long range development plan, conceived as a general guide to final objectives, uses many diagrams and maps to illustrate the text. The plan is predicated on the assumption that orderly and efficient development of site possibilities is subject to ever-changing influences. The following areas are examined--(1) campus environment, (2) academic…

  10. Long-Range Planning--Finances. Higher Education.

    ERIC Educational Resources Information Center

    Ward, Robert C.

    This paper presents views on long-range financial planning for public and private higher education. Emphasis is placed on a mix of revenue sources for future support and on key budgetary considerations such as faculty and non-academic wages, the rising cost of graduate education, and the community and junior college movement. A triple crisis is…

  11. Transport in Nonneutral Plasmas due to Long-Range Collisions

    NASA Astrophysics Data System (ADS)

    Anderegg, F.; Driscoll, C. F.; Hollmann, E. M.; Kriesel, J. M.; Huang, X.-P.; Dubin, D. H. E.; O'Neil, T. M.

    1997-11-01

    Recent experiments on nonneutral plasmas have measured test particle transport, bulk viscous transport, and heat transport; all three measurements show enhanced transport due to long-range interactions. Classical Boltzmann theory describes transport in terms of short-range velocity-scattering collisions with impact parameters less than the cyclotron radius, i.e. ρ < r_c. Here we observe the effects of long-range collisions with rc < ρ applteq λ_D. Experiments show that: a) The measured test particle diffusion across B is about ten times faster than predicted by classical collisional theory, in precise agreement with long-range collisional theory over a wide range of parameters. b) Viscous transport measurements obtained from plasma density profiles relaxing to thermal equilibrium indicate that bulk particle transport across the magnetic field may be enhanced by up to 10^4. c) Preliminary measurements of heat transport created by localized laser cooling or heating indicate that the thermal conductivity can be much larger than predicted by classical theory, consistent with long-range theory. Supported by ONR N00014-96-1-0239 and NSF PHY94-21318. ^**Present address: NIST, 325 Broadway Ave., Boulder CO 80303.

  12. Long Range Development Plan, University of California, Riverside.

    ERIC Educational Resources Information Center

    Russell (George Vernon) and Associates, Architects and Planners.

    A long range development plan, conceived as a general guide to final objectives, uses many diagrams and maps to illustrate the text. The plan is predicated on the assumption that orderly and efficient development of site possibilities is subject to ever-changing influences. The following areas are examined--(1) campus environment, (2) academic…

  13. Report of the Board Committee on Long Range Planning.

    ERIC Educational Resources Information Center

    National Association of Educational Broadcasters, Washington, DC.

    The impact of predicted technological developments on educational broadcasting depends on the long range planning done to exploit them. It is expected that in the future computers will be used extensively by broadcasting agencies to collect, analyze, and provide, on call, a wide range of data about audience groupings. Determination of program…

  14. [The Long-Range Plan for Colorado College.

    ERIC Educational Resources Information Center

    Brooks, Glenn

    This is a series of 3 reports to the Colorado College faculty and administration on a long-range plan. The first report deals with some of the technical features of a modular course plan, mainly: (1) the construction of a modular schedule, (2) registration and enrollment procedures, and (3) campus space and fixtures. The second report contains a…

  15. Strategic Long Range Planning for Universities. AIR Forum 1980 Paper.

    ERIC Educational Resources Information Center

    Baker, Michael E.

    The use of strategic long-range planning at Carnegie-Mellon University (CMU) is discussed. A structure for strategic planning analysis that integrates existing techniques is presented, and examples of planning activities at CMU are included. The key concept in strategic planning is competitive advantage: if a university has a competitive…

  16. SOVIET LONG-RANGE SPACE-EXPLORATION PROGRAM: ANALYTICAL SURVEY

    DTIC Science & Technology

    This analytical survey is based on Soviet open sources published 1956-1965. It is one of a series of reports dealing with the Soviet long-range space ... exploration program and is concerned, in particular, with lunar surface research. Information not directly related to this subject has been included

  17. Long-Range Correlations in Sentence Series from A Story of the Stone

    PubMed Central

    Yang, Tianguang; Gu, Changgui; Yang, Huijie

    2016-01-01

    A sentence is the natural unit of language. Patterns embedded in series of sentences can be used to model the formation and evolution of languages, and to solve practical problems such as evaluating linguistic ability. In this paper, we apply de-trended fluctuation analysis to detect long-range correlations embedded in sentence series from A Story of the Stone, one of the greatest masterpieces of Chinese literature. We identified a weak long-range correlation, with a Hurst exponent of 0.575±0.002 up to a scale of 104. We used the structural stability to confirm the behavior of the long-range correlation, and found that different parts of the series had almost identical Hurst exponents. We found that noisy records can lead to false results and conclusions, even if the noise covers a limited proportion of the total records (e.g., less than 1%). Thus, the structural stability test is an essential procedure for confirming the existence of long-range correlations, which has been widely neglected in previous studies. Furthermore, a combination of de-trended fluctuation analysis and diffusion entropy analysis demonstrated that the sentence series was generated by a fractional Brownian motion. PMID:27648941

  18. Long-Range Correlations in Sentence Series from A Story of the Stone.

    PubMed

    Yang, Tianguang; Gu, Changgui; Yang, Huijie

    2016-01-01

    A sentence is the natural unit of language. Patterns embedded in series of sentences can be used to model the formation and evolution of languages, and to solve practical problems such as evaluating linguistic ability. In this paper, we apply de-trended fluctuation analysis to detect long-range correlations embedded in sentence series from A Story of the Stone, one of the greatest masterpieces of Chinese literature. We identified a weak long-range correlation, with a Hurst exponent of 0.575±0.002 up to a scale of 104. We used the structural stability to confirm the behavior of the long-range correlation, and found that different parts of the series had almost identical Hurst exponents. We found that noisy records can lead to false results and conclusions, even if the noise covers a limited proportion of the total records (e.g., less than 1%). Thus, the structural stability test is an essential procedure for confirming the existence of long-range correlations, which has been widely neglected in previous studies. Furthermore, a combination of de-trended fluctuation analysis and diffusion entropy analysis demonstrated that the sentence series was generated by a fractional Brownian motion.

  19. Robustness of Estimators of Long-Range Dependence and Self-Similarity under non-Gaussianity

    NASA Astrophysics Data System (ADS)

    Franzke, C.; Watkins, N. W.; Graves, T.; Gramacy, R.; Hughes, C.

    2011-12-01

    Long-range dependence and non-Gaussianity are ubiquitous in many natural systems like ecosystems, biological systems and climate. However, it is not always appreciated that both phenomena may occur together in natural systems and that self-similarity in a system can be a superposition of both phenomena. These features, which are common in complex systems, impact the attribution of trends and the occurrence and clustering of extremes. The risk assessment of systems with these properties will lead to different outcomes (e.g. return periods) than the more common assumption of independence of extremes. Two paradigmatic models are discussed which can simultaneously account for long-range dependence and non-Gaussianity: Autoregressive Fractional Integrated Moving Average (ARFIMA) and Linear Fractional Stable Motion (LFSM). Statistical properties of estimators for long-range dependence and self-similarity are critically assessed. It is found that the most popular estimators can be biased in the presence of important features of many natural systems like trends and multiplicative noise. Also the long-range dependence and non-Gaussianity of two typical natural time series are discussed.

  20. Tunable long range forces mediated by self-propelled colloidal hard spheres

    NASA Astrophysics Data System (ADS)

    Ni, Ran; Cohen Stuart, Martien; Bolhuis, Peter

    2015-03-01

    Most colloidal interactions can be tuned by changing properties of the medium. Here we show that activating colloidal particles with random self-propulsion can induce giant effective interactions between large objects immersed in such a suspension. Using Brownian dynamics simulations we find that the effective force between two hard walls in a 2D suspension of self-propelled (active) colloidal hard spheres can be tuned from a long range repulsion into a long range attraction by changing the active particle density. At relatively high densities, the active hard spheres can form a dynamic crystalline bridge, which induces a strong oscillating long range dynamic wetting repulsion between the walls. With decreasing density, the dynamic bridge gradually breaks, and an intriguing long range dynamic depletion attraction arises. A similar effect occurs in a quasi-2D suspension of self-propelled colloidal hard spheres by changing the height of the confinement. Our results open up new possibilities to manipulate the motion and assembly of microscopic objects by using active matter.

  1. Probing the role of long-range interactions in the dynamics of a long-range Kitaev chain

    NASA Astrophysics Data System (ADS)

    Dutta, Anirban; Dutta, Amit

    2017-09-01

    We study the role of long-range interactions (more precisely, the long-range superconducting gap term) on the nonequilibrium dynamics considering a long-range p -wave superconducting chain in which the superconducting term decays with distance between two sites in a power-law fashion characterized by an exponent α . We show that the Kibble-Zurek scaling exponent, dictating the power-law decay of the defect density in the final state reached following a slow (in comparison to the time scale associated with the minimum gap in the spectrum of the Hamiltonian) quenching of the chemical potential μ across a quantum critical point, depends nontrivially on the exponent α as long as α <2 ; on the other hand, for α >2 , we find that the exponent saturates to the corresponding well-known value of 1 /2 expected for the short-range model. Furthermore, studying the dynamical quantum phase transitions manifested in the nonanalyticities in the rate function of the return possibility I (t ) in subsequent temporal evolution following a sudden change in μ , we show the existence of a new region; in this region, we find three instants of cusp singularities in I (t ) associated with a single sector of Fisher zeros. Notably, the width of this region shrinks as α increases and vanishes in the limit α →2 , indicating that this special region is an artifact of the long-range nature of the Hamiltonian.

  2. 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.

  3. Long-range intermolecular interaction between broken DNA fragments

    NASA Astrophysics Data System (ADS)

    Pinchuk, Anatoliy O.; Vysotskii, Vladimir I.

    2001-03-01

    We analyzed the long-range intermolecular interaction between fragments of broken DNA. We considered two constituents of long-range intermolecular interaction. The first is a net electrostatic Coulomb interaction between charges, involved in a structure of opposite nucleotides, which we evaluate using Debye-Huckel theory. The second one is the Van der Waals interaction between the nucleotides. The general Lifshitz theory of Van der Waals forces was used to evaluate this interaction. Numerical calculations showed that a repulsive force between broken DNA fragments can arise in specific cases. This repulsion can prevent DNA from repairing itself after a double-strand break. The height of the barrier decreases with an increase of the ionic strength of the intracellular milieu, or with a reduction of its viscosity.

  4. Temperature inversion in long-range interacting systems.

    PubMed

    Teles, Tarcísio N; Gupta, Shamik; Di Cintio, Pierfrancesco; Casetti, Lapo

    2015-08-01

    Temperature inversions occur in nature, e.g., in the solar corona and in interstellar molecular clouds: Somewhat counterintuitively, denser parts of the system are colder than dilute ones. We propose a simple and appealing way to spontaneously generate temperature inversions in systems with long-range interactions, by preparing them in inhomogeneous thermal equilibrium states and then applying an impulsive perturbation. In similar situations, short-range systems would typically relax to another thermal equilibrium, with a uniform temperature profile. By contrast, in long-range systems, the interplay between wave-particle interaction and spatial inhomogeneity drives the system to nonequilibrium stationary states that generically exhibit temperature inversion. We demonstrate this mechanism in a simple mean-field model and in a two-dimensional self-gravitating system. Our work underlines the crucial role the range of interparticle interaction plays in determining the nature of steady states out of thermal equilibrium.

  5. Entanglement Area Laws for Long-Range Interacting Systems

    NASA Astrophysics Data System (ADS)

    Gong, Zhe-Xuan; Foss-Feig, Michael; Brandão, Fernando G. S. L.; Gorshkov, Alexey V.

    2017-08-01

    We prove that the entanglement entropy of any state evolved under an arbitrary 1 /rα long-range-interacting D -dimensional lattice spin Hamiltonian cannot change faster than a rate proportional to the boundary area for any α >D +1 . We also prove that for any α >2 D +2 , the ground state of such a Hamiltonian satisfies the entanglement area law if it can be transformed along a gapped adiabatic path into a ground state known to satisfy the area law. These results significantly generalize their existing counterparts for short-range interacting systems, and are useful for identifying dynamical phase transitions and quantum phase transitions in the presence of long-range interactions.

  6. Long-range correlations in chaotic cellular automata

    NASA Astrophysics Data System (ADS)

    Eisele, Michael

    1991-03-01

    One-dimensional cellular automata of class 3 are studied as models for spatially extended, chaotic systems. Their irreversible dynamics can generate weak, but long-range spatial correlations. The one labelled 22 by Wolfram is treated in an exemplary way. Its stationary state is approximated by a Markov chain. The regular grammar underlying the Markov chain is chosen with care, so that it includes a maximum amount of information on the stationary state. The approximation can be performed without simulating the dynamics of the cellular automaton 22 and reproduces its long-range correlations qualitatively. Their origin is explained intuitively and they are argued to be a frequent feature of cellular automata with more complicated rules.

  7. Long-range correlation analysis of urban traffic data

    NASA Astrophysics Data System (ADS)

    Sheng, Peng; Wang, Jun-Feng; Tang, Tie-Qiao; Zhao, Shu-Long

    2010-08-01

    This paper investigates urban traffic data by analysing the long-range correlation with detrended fluctuation analysis. Through a large number of real data collected by the travel time detection system in Beijing, the variation of flow in different time periods and intersections is studied. According to the long-range correlation in different time scales, it mainly discusses the effect of intersection location in road net, people activity customs and special traffic controls on urban traffic flow. As demonstrated by the obtained results, the urban traffic flow represents three-phase characters similar to highway traffic. Moreover, compared by the two groups of data obtained before and after the special traffic restrictions (vehicles with special numbered plates only run in a special workday) enforcement, it indicates that the rules not only reduce the flow but also avoid irregular fluctuation.

  8. Long-range hybrid ridge and trench plasmonic waveguides

    SciTech Connect

    Bian, Yusheng; Gong, Qihuang

    2014-06-23

    We report a class of long-range hybrid plasmon polariton waveguides capable of simultaneously achieving low propagation loss and tight field localization at telecommunication wavelength. The symmetric (quasi-symmetric) hybrid configurations featuring high-refractive-index-contrast near the non-uniform metallic nanostructures enable significantly improved optical performance over conventional hybrid waveguides, exhibiting considerably longer propagation distances and dramatically enhanced figure of merits for similar degrees of confinement. Compared to their traditional long-range plasmonic counterparts, the proposed hybrid waveguides put much less stringent requirements on index-matching conditions, demonstrating nice performance under a wide range of physical dimensions and robust characteristics against certain fabrication imperfections. Studies concerning crosstalk between adjacent identical waveguides further reveal their potential for photonic integrations. In addition, alternative configurations with comparable guiding properties to the structures in our case studies are also proposed, which can potentially serve as attractive prototypes for numerous high-performance nanophotonic components.

  9. The design of a long-range megatransport aircraft

    NASA Technical Reports Server (NTRS)

    Weisshaar, Terrence A.; Allen, Carl L.

    1992-01-01

    Aircraft manufacturers are examining the market and feasibility of long-range passenger aircraft carrying more than 600 passengers. These aircraft would carry travelers at reduced cost and, at the same time, reduce congestion around major airports. The design of a large, long-range transport involves broad issues such as: the integration of airport terminal facilities; passenger loading and unloading; trade-offs between aircraft size and the cost to reconfigure these existing facilities; and, defeating the 'square-cube' law. Thirteen Purdue design teams generated RFP's that defined passenger capability and range, based upon team perception of market needs and infrastructure constraints. Turbofan engines were designed by each group to power these aircraft. The design problem and the variety of solutions developed are reviewed.

  10. The Dependence of Long-Range Reverberation on Bottom Roughness

    NASA Astrophysics Data System (ADS)

    Gauss, Roger; Fromm, David; LePage, Kevin; Gragg, Robert

    2004-11-01

    At long-range, shallow-water reverberation can be driven by sub-critical-angle scattering, i.e. by rough interrace scattering. The Naval Research Laboratory has recently developed a small-slope model for elastic seafloors that provides physics-based estimates of the dependence of scattering on the incident and scattered angles, and physical descriptors of the environment. In this paper, this incoherent model is used as kernels in reverberation models, which in turn are used to assess the sensitivity at 3.5 kHz of long-range monostatic reverberation to the roughness of the water-sediment interface. It is shown that when sub-critical-angle scattering dominates, the acoustic field could be quite sensitive to the parameter values of the roughness, thus arguing for the need for regional in-situ methods for its estimation.

  11. Travel: a long-range goal of retired women.

    PubMed

    Staats, Sara; Pierfelice, Loretta

    2003-09-01

    The authors surveyed retired persons (predominately women) with regard to their immediate, intermediate, and long-range activities following retirement. As predicted, leisure travel emerged as a frequent long-range goal for persons retired more than 5 years. The travel activity preferences of long-retired older women present challenges and opportunities to both researchers and marketers. Length of trips and frequency of trips have been predicted from regression models, with trip length in particular being well predicted by the problem of daily life hassles. A theoretical model of continued post-retirement travel is presented as a variant of Solomon's opponent process theory of affect (R. L. Solomon, 1980). The authors suggest that to the degree that places traveled to are varied and different, older people may remain stimulated and continue to enjoy retirement.

  12. Reaching for the Horizon: The 2015 NSAC Long Range Plan

    NASA Astrophysics Data System (ADS)

    Geesaman, Donald

    2015-10-01

    In April 2014, the Nuclear Science Advisory Committee was charged to conduct a new study of the opportunities and priorities for United States nuclear physics research and to recommend a long range plan for the coordinated advancement of the Nation's nuclear science program over the next decade. The entire community actively contributed to developing this plan. Ideas and goals, new and old, were examined and community priorities were established. The Long Range Plan Working Group gathered at Kitty Hawk, NC to converge on the recommendations. In this talk I will discuss the vision for the future that has emerged from this process. The new plan, ``Reaching for the Horizon,'' offers the promise of great leaps forward in our understanding of nuclear science and new opportunities for nuclear science to serve society. This work was supported by the U. S. Department of Energy, Office of Science, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357.

  13. Long-range mutual information and topological uncertainty principle

    NASA Astrophysics Data System (ADS)

    Jian, Chao-Ming; Kim, Isaac; Qi, Xiao-Liang

    Ordered phases in Landau paradigm can be diagnosed by a local order parameter, whereas topologically ordered phases cannot be detected in such a way. In this paper, we propose long-range mutual information (LRMI) as a unified diagnostic for both conventional long-range order and topological order. Using the LRMI, we characterize orders in n +1D gapped systems as m-membrane condensates with 0 <= m <= n-1. The familiar conventional order and 2 +1D topological orders are respectively identified as 0-membrane and 1-membrane condensates. We propose and study the topological uncertainty principle, which describes the non-commuting nature of non-local order parameters in topological orders.

  14. Long-range exciton dissociation in organic solar cells.

    PubMed

    Caruso, Domenico; Troisi, Alessandro

    2012-08-21

    It is normally assumed that electrons and holes in organic solar cells are generated by the dissociation of excitons at the interface between donor and acceptor materials in strongly bound hole-electron pairs. We show in this contribution that excitons can dissociate tens of angstroms away from the interface and generate partially separated electrons and holes, which can more easily overcome their coulombic attraction and form free charges. We first establish under what conditions long-range exciton dissociation is likely (using a kinetic model and a microscopic model for the calculation of the long-range electron transfer rate). Then, defining a rather general model Hamiltonian for the donor material, we show that the phenomenon is extremely common in the majority of polymer:fullerene bulk heterojunction solar cells.

  15. Long range science scheduling for the Hubble Space Telescope

    NASA Technical Reports Server (NTRS)

    Miller, Glenn; Johnston, Mark

    1991-01-01

    Observations with NASA's Hubble Space Telescope (HST) are scheduled with the assistance of a long-range scheduling system (SPIKE) that was developed using artificial intelligence techniques. In earlier papers, the system architecture and the constraint representation and propagation mechanisms were described. The development of high-level automated scheduling tools, including tools based on constraint satisfaction techniques and neural networks is described. The performance of these tools in scheduling HST observations is discussed.

  16. The design of a long range megatransport aircraft

    NASA Technical Reports Server (NTRS)

    Weisshaar, Terrence A.; Allen, Carl L.

    1992-01-01

    During the period from August 1991 - June 1992 two design classes at Purdue University participated in the design of a long range, high capacity transport aircraft, dubbed the megatransport. Thirteen Purdue design teams generated RFP's that defined passenger capability and range, based upon team perception of market needs and infrastructure constraints. Turbofan engines were designed by each group to power these aircraft. The design problem and the variety of solutions developed are described in an attached paper.

  17. Frequency multiplexed long range swept source optical coherence tomography

    PubMed Central

    Zurauskas, Mantas; Bradu, Adrian; Podoleanu, Adrian Gh.

    2013-01-01

    We present a novel swept source optical coherence tomography configuration, equipped with acousto-optic deflectors that can be used to simultaneously acquire multiple B-scans originating from different depths. The sensitivity range of the configuration is evaluated while acquiring five simultaneous B-scans. Then the configuration is employed to demonstrate long range B-scan imaging by combining two simultaneous B-scans from a mouse head sample. PMID:23760762

  18. Dissipative long-range entanglement generation between electronic spins

    NASA Astrophysics Data System (ADS)

    Benito, M.; Schuetz, M. J. A.; Cirac, J. I.; Platero, G.; Giedke, G.

    2016-09-01

    We propose a scheme for deterministic generation and long-term stabilization of entanglement between two electronic spin qubits confined in spatially separated quantum dots. Our approach relies on an electronic quantum bus, consisting either of quantum Hall edge channels or surface acoustic waves, that can mediate long-range coupling between localized spins over distances of tens of micrometers. Since the entanglement is actively stabilized by dissipative dynamics, our scheme is inherently robust against noise and imperfections.

  19. Long Range Interactions With Laser Cooled Neutral Atoms

    SciTech Connect

    Gattobigio, Giovanni Luca; Michaud, Franck; Labeyrie, Guillaume; Kaiser, Robin; Loureiro, Jorge; Mendonca, Jose Tito; Tercas, Hugo; Pohl, Thomas

    2008-09-07

    Multiple scattering of light in a trap of laser cooled neutral atoms leads to repulsion forces between the atoms. The corresponding interactions have long range behavior in 1/r{sup 2} and are thus similar to Coulomb interaction in an one component confined plasma. Consequences of these interactions will be described in this paper, including the limitation of the spatial density one can obtain in such systems and self-sustained oscillations of the cloud.

  20. Extreme long range process effects characterization and compensation

    NASA Astrophysics Data System (ADS)

    Figueiro, Thiago; Browning, Clyde; Thornton, Martin J.; Vannuffel, Cyril; Choi, Kang-Hoon; Hohle, Christoph; Tortai, Jean-Herve; Schiavone, Patrick

    2013-10-01

    Proximity Effects in electron beam lithography impact feature dimensions, pattern fidelity and uniformity. These effects are addressed using a mathematical model representing the radial exposure intensity distribution induced by a point electron source, commonly named as the Point Spread Function (PSF). PSF models are usually employed for predicting and compensating for effects up to 15μm. It is well known that there are also some process related phenomena that impact pattern uniformity that have a longer range, namely CMP effects, fogging, etc. Performing proximity effects corrections can result in lengthy run times as file size and pattern densities continue to increase exponentially per technology node. Running corrections for extreme long range phenomena becomes computational and file size prohibitive. Nevertheless, since extreme long range may reach up several millimeters, and new technology nodes require a high level of precision, a strategy for predicting and compensating these phenomena is crucial. In this paper a set of test patterns are presented in order to verify and calibrate the so called extreme long range effects in the electron beam lithography. Moreover, a strategy to compensate for extreme long range effects based on the pattern density is presented. Since the evaluation is based on a density map instead of the actual patterns, the computational effort is feasible. The proposed method may be performed off-line (in contrast to machine standard in-line correction). The advantage of employing off-line compensation relies on enhancing the employ of dose and/or geometry modulation. This strategy also has the advantage of being completely decoupled from other e-beam writer's internal corrections (like Fogging Effect Correction - FEC).

  1. Long-Range Tunneling Processes across Ferritin-Based Junctions.

    PubMed

    Kumar, Karuppannan Senthil; Pasula, Rupali Reddy; Lim, Sierin; Nijhuis, Christian A

    2016-03-02

    The mechanism of long-range charge transport across tunneling junctions with monolayers of ferritin is investigated. It is shown that the mechanism can be switched between coherent tunneling, sequential tunneling, and hopping by changing the iron content inside the ferritin. This study shows that ferritins are an interesting class of biomolecules to control charge transport. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Long range Ising model for credit risk modeling

    NASA Astrophysics Data System (ADS)

    Molins, Jordi; Vives, Eduard

    2005-07-01

    Within the framework of maximum entropy principle we show that the finite-size long-range Ising model is the adequate model for the description of homogeneous credit portfolios and the computation of credit risk when default correlations between the borrowers are included. The exact analysis of the model suggest that when the correlation increases a first-order-like transition may occur inducing a sudden risk increase.

  3. IMI long-range surface plasmon Bragg micro-cavity

    NASA Astrophysics Data System (ADS)

    Tong, Kai; Wang, Jun; Zhou, Chunliang; Wang, Meiting

    2016-10-01

    The defect layer is introduced to the insulator-metal-insulator (IMI) Bragg waveguide structure. The micro-cavity structure of long-range surface plasma is proposed based on the defect mode. The liquid crystal is the defect layer in the structure of Bragg. The energy band characteristics of the long-range surface plasmon Bragg micro-cavity structure are analyzed by using the finite difference time domain method. The influence of the period number and the length of the micro-cavity on the quality factor Q and the volume V of the Bragg grating are discussed. The results show that the photonic energy can be confined very well in the micro-cavity by the structure of the micro-cavity. By controlling the birefringence of liquid crystal, the resonance wavelength of the micro-cavity appears with redshift phenomenon. The tuning range is 42 nm. The tuning of the working window of the long-range surface plasmon filter is realized. The photonic energy is the strongest in the insulating layer and the metal interface. The increase of cycles number has certain limitation on the improvement of the quality factor Q of the cavity. The influence of the defect-cavity length on the resonant wavelength, the quality factor Q and the mode volume V is obvious. The performance of the micro-cavity can be improved by adjusting the number of the micro-cavity and the length of the defect-cavity, and the ratio of Q/V can reach 43,750 in the communication band. The nano micro-cavity provides a new design idea and basis for the fabrication of tunable long-range surface plasmon wave filter in this paper.

  4. Emergent long-range couplings in arrays of fluid cells

    SciTech Connect

    Abraham, Douglas Bruce

    2014-08-07

    We present a system exhibiting extraordinarily long-range cooperative effects, on a length scale far exceeding the bulk correlation length. We give a theoretical explanation of these phenomena based on the mesoscopic picture of phase coexistence in finite systems, which is confirmedly Monte Carlo (MC) simulation studies. Our work demonstrates that such action-at-a-distance can occur in classical systems involving simple or complex fluids, such as colloid-polymer mixtures, or ferromagnets.

  5. Acceleration of Evolutionary Spread by Long-Range Dispersal

    NASA Astrophysics Data System (ADS)

    Hallatschek, Oskar

    2014-03-01

    The spreading of evolutionary novelties across populations is the central element of adaptation. Unless population are well-mixed (like bacteria in a shaken test tube), the spreading dynamics not only depends on fitness differences but also on the dispersal behavior of the species. Spreading at a constant speed is generally predicted when dispersal is sufficiently short-ranged. However, the case of long-range dispersal is unresolved: While it is clear that even rare long-range jumps can lead to a drastic speedup, it has been difficult to analyze the ensuing stochastic growth process. We present a simple self-consistent argument supported by simulations that accurately predicts evolutionary spread for broad distributions of long distance dispersal. In contrast to the exponential laws predicted by deterministic ``mean-field'' models, spread is either according to a super-linear power-law or a stretched exponential law, depending on the tails of the dispersal kernel. Fluctuations and the relation to supercritical long-range percolation are discussed. Due to the simplicity of our model, which lacks any complex interactions between individuals, we expect our results to be applicable to a wide range of spreading processes. Our results may be used, in particular, to estimate the spread of modern human epidemics, which are greatly accelerated by the human aviation. Based on joint work with Daniel S. Fisher, Stanford.

  6. Observation of prethermalization in long-range interacting spin chains

    PubMed Central

    Neyenhuis, Brian; Zhang, Jiehang; Hess, Paul W.; Smith, Jacob; Lee, Aaron C.; Richerme, Phil; Gong, Zhe-Xuan; Gorshkov, Alexey V.; Monroe, Christopher

    2017-01-01

    Although statistical mechanics describes thermal equilibrium states, these states may or may not emerge dynamically for a subsystem of an isolated quantum many-body system. For instance, quantum systems that are near-integrable usually fail to thermalize in an experimentally realistic time scale, and instead relax to quasi-stationary prethermal states that can be described by statistical mechanics, when approximately conserved quantities are included in a generalized Gibbs ensemble (GGE). We experimentally study the relaxation dynamics of a chain of up to 22 spins evolving under a long-range transverse-field Ising Hamiltonian following a sudden quench. For sufficiently long-range interactions, the system relaxes to a new type of prethermal state that retains a strong memory of the initial conditions. However, the prethermal state in this case cannot be described by a standard GGE; it rather arises from an emergent double-well potential felt by the spin excitations. This result shows that prethermalization occurs in a broader context than previously thought, and reveals new challenges for a generic understanding of the thermalization of quantum systems, particularly in the presence of long-range interactions. PMID:28875166

  7. Segmentation of time series with long-range fractal correlations

    NASA Astrophysics Data System (ADS)

    Bernaola-Galván, P.; Oliver, J. L.; Hackenberg, M.; Coronado, A. V.; Ivanov, P. Ch.; Carpena, P.

    2012-06-01

    Segmentation is a standard method of data analysis to identify change-points dividing a nonstationary time series into homogeneous segments. However, for long-range fractal correlated series, most of the segmentation techniques detect spurious change-points which are simply due to the heterogeneities induced by the correlations and not to real nonstationarities. To avoid this oversegmentation, we present a segmentation algorithm which takes as a reference for homogeneity, instead of a random i.i.d. series, a correlated series modeled by a fractional noise with the same degree of correlations as the series to be segmented. We apply our algorithm to artificial series with long-range correlations and show that it systematically detects only the change-points produced by real nonstationarities and not those created by the correlations of the signal. Further, we apply the method to the sequence of the long arm of human chromosome 21, which is known to have long-range fractal correlations. We obtain only three segments that clearly correspond to the three regions of different G + C composition revealed by means of a multi-scale wavelet plot. Similar results have been obtained when segmenting all human chromosome sequences, showing the existence of previously unknown huge compositional superstructures in the human genome.

  8. Segmentation of time series with long-range fractal correlations

    PubMed Central

    Bernaola-Galván, P.; Oliver, J.L.; Hackenberg, M.; Coronado, A.V.; Ivanov, P.Ch.; Carpena, P.

    2012-01-01

    Segmentation is a standard method of data analysis to identify change-points dividing a nonstationary time series into homogeneous segments. However, for long-range fractal correlated series, most of the segmentation techniques detect spurious change-points which are simply due to the heterogeneities induced by the correlations and not to real nonstationarities. To avoid this oversegmentation, we present a segmentation algorithm which takes as a reference for homogeneity, instead of a random i.i.d. series, a correlated series modeled by a fractional noise with the same degree of correlations as the series to be segmented. We apply our algorithm to artificial series with long-range correlations and show that it systematically detects only the change-points produced by real nonstationarities and not those created by the correlations of the signal. Further, we apply the method to the sequence of the long arm of human chromosome 21, which is known to have long-range fractal correlations. We obtain only three segments that clearly correspond to the three regions of different G + C composition revealed by means of a multi-scale wavelet plot. Similar results have been obtained when segmenting all human chromosome sequences, showing the existence of previously unknown huge compositional superstructures in the human genome. PMID:23645997

  9. Long-range infrasound monitoring of eruptive volcanoes.

    NASA Astrophysics Data System (ADS)

    Marchetti, Emanuele; Innocenti, Lorenzo; Ulivieri, Giacomo; Lacanna, Giorgio; Ripepe, Maurizio

    2016-04-01

    The efficient long-range propagation in the atmosphere makes infrasound of active volcanoes extremely promising and opens new perspectives for volcano monitoring at large scale. In favourable propagation conditions, long-range infrasound observations can be used to track the occurrence and the duration of volcanic eruptions also at remote non-monitored volcanoes, but its potential to infer volcanic eruptive source term is still debated. We present results of comparing five years of infrasound of eruptive activity at Mt.Etna volcano (Italy) recorded both at local (~5 km) and at regional distances (~600 km) from the source. Infrasound of lava fountains at Etna volcano, occurring in between 2010 and 2015, are analysed in terms of the local and regional wavefield record, and by comparing to all available volcanic source terms (i.e. plume height and mass eruption rates). Besides, the potential of near real-time notification of ongoing volcanic activity at Etna volcano at a regional scale is investigated. In particular we show how long range infrasound, in the case of Etna volcano, can be used to promptly deliver eruption notification and reliability is constrained by the results of the local array. This work is performed in the framework of the H2020 ARISE2 project funded by the EU in the period 2015-2018.

  10. Long-range scaling behaviours of human colonic pressure activities

    NASA Astrophysics Data System (ADS)

    Yan, Rongguo; Yan, Guozheng; Zhang, Wenqiang; Wang, Long

    2008-11-01

    The long-range scaling behaviours of human colonic pressure activities under normal physiological conditions are studied by using the method of detrended fluctuation analysis (DFA). The DFA is an effective period representation with a single quantitative scaling exponent α to accurately quantify long-range correlations naturally presented in a complex non-stationary time series. The method shows that the colonic activities of the healthy subjects exhibit long-range power-law correlations; however such correlations either will be destroyed if we randomly shuffle the original data or will cease to be of a power-law form if we chop some high-amplitude spikes off. These facts indicate that the colonic tissue or enteric nervous system (ENS) with a good functional motility has a good memory to its past behaviours and generates well-organized colonic spikes; however such good memory becomes too long to be remembered for the colonic activity of the slow transit constipation (STC) patient and colonic dysmotility occurs.

  11. Continuous concentric lamellar block copolymer nanofibers with long range order.

    PubMed

    Ma, Minglin; Titievsky, Kirill; Thomas, Edwin L; Rutledge, Gregory C

    2009-04-01

    Fibers with long-range ordered internal structures have applications in various areas such as photonic band gap fibers, optical waveguides, wearable power, sensors, and sustained drug release. Up to now, such fibers have been formed by melt extrusion or drawing from a macroscopic preformed rod and were typically limited to diameters >10 microm with internal features >1 microm (Abouraddy, A. F.; et al. Nat. Mater. 2007, 6, 336). We describe a new class of continuous fibers and fibrous membranes with long-range ordered concentric lamellar structure that have fiber diameters and feature sizes 2-3 orders of magnitude smaller than those made by conventional methods. These fibers are created through confined self-assembly of block copolymers within core-shell electrospun filaments. In contrast to the copolymer in bulk or thin films, the domains of the concentric lamellar structure are shown here to vary quantitatively with (radial) position and to exhibit a novel dislocation that accommodates variations in fiber diameter robustly, permitting for the first time the realization of long-range order in technologically meaningful, continuous fibers with approximately 300 nm diameter and 50 nm radial period.

  12. Possible Long Range Component in the Nuclear Force

    NASA Astrophysics Data System (ADS)

    Sawada, T.

    In search of the possible long range force between hadrons, S wave phase shift data of the proton-proton scattering are analyzed. In the analysis, the once subtracted Kantor amplitude is calculated, and the one-pion exchange contribution is separated. The remainder of the Kantor amplitude has a huge cusp at the threshold with the attractive sign. It is shown that such a cusp cannot be fitted by the spectral function of the twopion exchange, since it starts at t = 4μ {π }2 . The cusp is fitted by a potential of the long range type with the asymptotic form of V(r) -C/rα. After the chi square search, it turns out α is 6.1 7 and C is positive and has the strength of the strong interaction. It is consistent with the potential of the strong van der Waals force. The transition from the London type to the Casimir-Polder type of the van der Waals interaction is examined. Possible experiments to observe directly such a long range force in the nuclear force are also indicated.

  13. Observation of prethermalization in long-range interacting spin chains.

    PubMed

    Neyenhuis, Brian; Zhang, Jiehang; Hess, Paul W; Smith, Jacob; Lee, Aaron C; Richerme, Phil; Gong, Zhe-Xuan; Gorshkov, Alexey V; Monroe, Christopher

    2017-08-01

    Although statistical mechanics describes thermal equilibrium states, these states may or may not emerge dynamically for a subsystem of an isolated quantum many-body system. For instance, quantum systems that are near-integrable usually fail to thermalize in an experimentally realistic time scale, and instead relax to quasi-stationary prethermal states that can be described by statistical mechanics, when approximately conserved quantities are included in a generalized Gibbs ensemble (GGE). We experimentally study the relaxation dynamics of a chain of up to 22 spins evolving under a long-range transverse-field Ising Hamiltonian following a sudden quench. For sufficiently long-range interactions, the system relaxes to a new type of prethermal state that retains a strong memory of the initial conditions. However, the prethermal state in this case cannot be described by a standard GGE; it rather arises from an emergent double-well potential felt by the spin excitations. This result shows that prethermalization occurs in a broader context than previously thought, and reveals new challenges for a generic understanding of the thermalization of quantum systems, particularly in the presence of long-range interactions.

  14. Long-range electrostatic screening in ionic liquids.

    PubMed

    Gebbie, Matthew A; Dobbs, Howard A; Valtiner, Markus; Israelachvili, Jacob N

    2015-06-16

    Electrolyte solutions with high concentrations of ions are prevalent in biological systems and energy storage technologies. Nevertheless, the high interaction free energy and long-range nature of electrostatic interactions makes the development of a general conceptual picture of concentrated electrolytes a significant challenge. In this work, we study ionic liquids, single-component liquids composed solely of ions, in an attempt to provide a novel perspective on electrostatic screening in very high concentration (nonideal) electrolytes. We use temperature-dependent surface force measurements to demonstrate that the long-range, exponentially decaying diffuse double-layer forces observed across ionic liquids exhibit a pronounced temperature dependence: Increasing the temperature decreases the measured exponential (Debye) decay length, implying an increase in the thermally driven effective free-ion concentration in the bulk ionic liquids. We use our quantitative results to propose a general model of long-range electrostatic screening in ionic liquids, where thermally activated charge fluctuations, either free ions or correlated domains (quasiparticles), take on the role of ions in traditional dilute electrolyte solutions. This picture represents a crucial step toward resolving several inconsistencies surrounding electrostatic screening and charge transport in ionic liquids that have impeded progress within the interdisciplinary ionic liquids community. More broadly, our work provides a previously unidentified way of envisioning highly concentrated electrolytes, with implications for diverse areas of inquiry, ranging from designing electrochemical devices to rationalizing electrostatic interactions in biological systems.

  15. Characterization of long-range transport of aerosols over Austria

    NASA Astrophysics Data System (ADS)

    Talianu, Camelia; Seibert, Petra

    2017-04-01

    The long-range transport of aerosols over Austria is characterized using measurements from EARLINET lidar stations and AERONET stations closest to Austria, and aerosol transport models. The analysis is based on selected events of long-range transport of aerosols recorded over Central and South-Eastern Europe: dust, biomass burning, continental aerosols and a special case of volcanic ash, using measurements from EARLINET and AERONET stations around Austria: Garmisch-Partenkirchen, Munich, Leipzig (all stations located in Germany), and Bucharest (Romania). Aerosol layers have been determined using a wavelet analysis applied to the lidar measurements. The optical properties of these aerosols have been also determined from lidar and sunphotometer measurements. The analysis of the trajectories has been performed with the FLEXTRA model, while the estimation of the potential areas of aerosols' sources has been performed using FLEXPART transport model. Based on the spatial and temporal distributions of the trajectories, the main groups of trajectories have been identified using a cluster analysis. The results shows that the long-range transported aerosols over Austria in the spring and summer seasons originate mainly from Sahara (dust) and Canada (biomass burning), coming over Germany. A comparison of the results with the CALIPSO satellite measurements over Austria is also performed. Supported by Austrian Science Fund FWF, Project M 2031, Meitner-Programm.

  16. Long range interactions on wires: A reciprocal space based formalism

    NASA Astrophysics Data System (ADS)

    Mináry, Peter; Morrone, Joseph A.; Yarne, Dawn A.; Tuckerman, Mark E.; Martyna, Glenn J.

    2004-12-01

    There are many atomic scale systems in materials, chemistry, and biology that can be effectively modeled as finite in two of the physical spatial dimensions and periodically replicated in the third including nanoscale metallic and semiconducting wires, carbon nanotubes, and DNA. However, it is difficult to design techniques to treat long range forces in these systems without truncation or recourse to slowly convergent supercells or computationally inefficient Poisson solvers. In this paper, a rigorous reciprocal space based formalism which permits long range forces on wires to be evaluated simply and easily via a small modification of existing methods for three dimensional periodicity is derived. The formalism is applied to determine long range interactions both between point particles using an Ewald-like approach and the continuous charge distributions that appear in electronic structure calculations. In this way, both empirical force field calculations and, for example, plane-wave based density functional theory computations on wires can be performed easily. The methodology is tested on model and realistic systems including a lithium doped carbon nanotube.

  17. Long-range electrostatic screening in ionic liquids

    PubMed Central

    Gebbie, Matthew A.; Dobbs, Howard A.; Valtiner, Markus; Israelachvili, Jacob N.

    2015-01-01

    Electrolyte solutions with high concentrations of ions are prevalent in biological systems and energy storage technologies. Nevertheless, the high interaction free energy and long-range nature of electrostatic interactions makes the development of a general conceptual picture of concentrated electrolytes a significant challenge. In this work, we study ionic liquids, single-component liquids composed solely of ions, in an attempt to provide a novel perspective on electrostatic screening in very high concentration (nonideal) electrolytes. We use temperature-dependent surface force measurements to demonstrate that the long-range, exponentially decaying diffuse double-layer forces observed across ionic liquids exhibit a pronounced temperature dependence: Increasing the temperature decreases the measured exponential (Debye) decay length, implying an increase in the thermally driven effective free-ion concentration in the bulk ionic liquids. We use our quantitative results to propose a general model of long-range electrostatic screening in ionic liquids, where thermally activated charge fluctuations, either free ions or correlated domains (quasiparticles), take on the role of ions in traditional dilute electrolyte solutions. This picture represents a crucial step toward resolving several inconsistencies surrounding electrostatic screening and charge transport in ionic liquids that have impeded progress within the interdisciplinary ionic liquids community. More broadly, our work provides a previously unidentified way of envisioning highly concentrated electrolytes, with implications for diverse areas of inquiry, ranging from designing electrochemical devices to rationalizing electrostatic interactions in biological systems. PMID:26040001

  18. Long-range surface modes supported by thin films

    NASA Astrophysics Data System (ADS)

    Yang, Fuzi; Sambles, J. R.; Bradberry, G. W.

    1991-09-01

    A detailed analysis of the surface modes of a thin slab of material of dielectric constant ɛ2 (=ɛr2-iɛi2) surrounded symmetrically by dielectric media is presented. Results show that in the thin-film limit, as well as the well-known long-range surface plasmon for a thin metal layer and the TM guided mode for a thin dielectric, a long-range surface mode exists for almost any value of ɛ2. This is even true if the imaginary part of ɛ2, ɛi2, is much larger than the real part ɛr2. We also find that a long-range surface mode may arise from the coupling between two surfaces which individually cannot support a surface mode. These are a pair of special coupled-surface modes which may exist below a certain critical film thickness and which have two separate propagation vectors each with the same field symmetry. It is also found that the inverse situation may pertain, that is for certain relative values of dielectric constants even though ordinary surface modes may exist, below a critical thickness the resulting coupled long-range mode no longer exists. The analysis has also been extended to practical situations with weakly absorbing surrounding media and to circumstances where the dielectric constants of the surrounding media are slightly different. Both of these effects modify the dispersion relations obtained for the simple case and introduce further limit thicknesses into the problem. Analytic formulas in the thin-film limit are presented for all the above situations and field distributions and energy flow (Poynting vector) profiles presented to illustrate as necessary the nature of the modes supported by these systems. Finally experimental results are presented which illustrate the rather sweeping conclusion that a long-range surface mode may exist on a thin film for almost all values of ɛr2 and ɛi2. This result paves the way for a range of optics experiments on absorbing structures.

  19. Long-ranged contributions to solvation free energies from theory and short-ranged models

    PubMed Central

    Remsing, Richard C.; Liu, Shule; Weeks, John D.

    2016-01-01

    Long-standing problems associated with long-ranged electrostatic interactions have plagued theory and simulation alike. Traditional lattice sum (Ewald-like) treatments of Coulomb interactions add significant overhead to computer simulations and can produce artifacts from spurious interactions between simulation cell images. These subtle issues become particularly apparent when estimating thermodynamic quantities, such as free energies of solvation in charged and polar systems, to which long-ranged Coulomb interactions typically make a large contribution. In this paper, we develop a framework for determining very accurate solvation free energies of systems with long-ranged interactions from models that interact with purely short-ranged potentials. Our approach is generally applicable and can be combined with existing computational and theoretical techniques for estimating solvation thermodynamics. We demonstrate the utility of our approach by examining the hydration thermodynamics of hydrophobic and ionic solutes and the solvation of a large, highly charged colloid that exhibits overcharging, a complex nonlinear electrostatic phenomenon whereby counterions from the solvent effectively overscreen and locally invert the integrated charge of the solvated object. PMID:26929375

  20. Cooperative Shielding in Many-Body Systems with Long-Range Interaction.

    PubMed

    Santos, Lea F; Borgonovi, Fausto; Celardo, Giuseppe Luca

    2016-06-24

    In recent experiments with ion traps, long-range interactions were associated with the exceptionally fast propagation of perturbation, while in some theoretical works they have also been related with the suppression of propagation. Here, we show that such apparently contradictory behavior is caused by a general property of long-range interacting systems, which we name cooperative shielding. It refers to shielded subspaces that emerge as the system size increases and inside of which the evolution is unaffected by long-range interactions for a long time. As a result, the dynamics strongly depends on the initial state: if it belongs to a shielded subspace, the spreading of perturbation satisfies the Lieb-Robinson bound and may even be suppressed, while for initial states with components in various subspaces, the propagation may be quasi-instantaneous. We establish an analogy between the shielding effect and the onset of quantum Zeno subspaces. The derived effective Zeno Hamiltonian successfully describes the short-ranged dynamics inside the subspaces up to a time scale that increases with system size. Cooperative shielding can be tested in current experiments with trapped ions.

  1. Long-ranged contributions to solvation free energies from theory and short-ranged models

    NASA Astrophysics Data System (ADS)

    Remsing, Richard C.; Liu, Shule; Weeks, John D.

    2016-03-01

    Long-standing problems associated with long-ranged electrostatic interactions have plagued theory and simulation alike. Traditional lattice sum (Ewald-like) treatments of Coulomb interactions add significant overhead to computer simulations and can produce artifacts from spurious interactions between simulation cell images. These subtle issues become particularly apparent when estimating thermodynamic quantities, such as free energies of solvation in charged and polar systems, to which long-ranged Coulomb interactions typically make a large contribution. In this paper, we develop a framework for determining very accurate solvation free energies of systems with long-ranged interactions from models that interact with purely short-ranged potentials. Our approach is generally applicable and can be combined with existing computational and theoretical techniques for estimating solvation thermodynamics. We demonstrate the utility of our approach by examining the hydration thermodynamics of hydrophobic and ionic solutes and the solvation of a large, highly charged colloid that exhibits overcharging, a complex nonlinear electrostatic phenomenon whereby counterions from the solvent effectively overscreen and locally invert the integrated charge of the solvated object.

  2. Acceleration of evolutionary spread by long-range dispersal

    PubMed Central

    Hallatschek, Oskar; Fisher, Daniel S.

    2014-01-01

    The spreading of evolutionary novelties across populations is the central element of adaptation. Unless populations are well mixed (like bacteria in a shaken test tube), the spreading dynamics depend not only on fitness differences but also on the dispersal behavior of the species. Spreading at a constant speed is generally predicted when dispersal is sufficiently short ranged, specifically when the dispersal kernel falls off exponentially or faster. However, the case of long-range dispersal is unresolved: Although it is clear that even rare long-range jumps can lead to a drastic speedup—as air-traffic–mediated epidemics show—it has been difficult to quantify the ensuing stochastic dynamical process. However, such knowledge is indispensable for a predictive understanding of many spreading processes in natural populations. We present a simple iterative scaling approximation supported by simulations and rigorous bounds that accurately predicts evolutionary spread, which is determined by a trade-off between frequency and potential effectiveness of long-distance jumps. In contrast to the exponential laws predicted by deterministic “mean-field” approximations, we show that the asymptotic spatial growth is according to either a power law or a stretched exponential, depending on the tails of the dispersal kernel. More importantly, we provide a full time-dependent description of the convergence to the asymptotic behavior, which can be anomalously slow and is relevant even for long times. Our results also apply to spreading dynamics on networks with a spectrum of long-range links under certain conditions on the probabilities of long-distance travel: These are relevant for the spread of epidemics. PMID:25368183

  3. Modelling control of epidemics spreading by long-range interactions

    PubMed Central

    Dybiec, Bartłomiej; Kleczkowski, Adam; Gilligan, Christopher A.

    2009-01-01

    We have studied the spread of epidemics characterized by a mixture of local and non-local interactions. The infection spreads on a two-dimensional lattice with the fixed nearest neighbour connections. In addition, long-range dynamical links are formed by moving agents (vectors). Vectors perform random walks, with step length distributed according to a thick-tail distribution. Two distributions are considered in this paper, an α-stable distribution describing self-similar vector movement, yet characterized by an infinite variance and an exponential power characterized by a large but finite variance. Such long-range interactions are hard to track and make control of epidemics very difficult. We also allowed for cryptic infection, whereby an infected individual on the lattice can be infectious prior to showing any symptoms of infection or disease. To account for such cryptic spread, we considered a control strategy in which not only detected, i.e. symptomatic, individuals but also all individuals within a certain control neighbourhood are treated upon the detection of disease. We show that it is possible to eradicate the disease by using such purely local control measures, even in the presence of long-range jumps. In particular, we show that the success of local control and the choice of the optimal strategy depend in a non-trivial way on the dispersal patterns of the vectors. By characterizing these patterns using the stability index of the α-stable distribution to change the power-law behaviour or the exponent characterizing the decay of an exponential power distribution, we show that infection can be successfully contained using relatively small control neighbourhoods for two limiting cases for long-distance dispersal and for vectors that are much more limited in their dispersal range. PMID:19126536

  4. Acceleration of evolutionary spread by long-range dispersal.

    PubMed

    Hallatschek, Oskar; Fisher, Daniel S

    2014-11-18

    The spreading of evolutionary novelties across populations is the central element of adaptation. Unless populations are well mixed (like bacteria in a shaken test tube), the spreading dynamics depend not only on fitness differences but also on the dispersal behavior of the species. Spreading at a constant speed is generally predicted when dispersal is sufficiently short ranged, specifically when the dispersal kernel falls off exponentially or faster. However, the case of long-range dispersal is unresolved: Although it is clear that even rare long-range jumps can lead to a drastic speedup--as air-traffic-mediated epidemics show--it has been difficult to quantify the ensuing stochastic dynamical process. However, such knowledge is indispensable for a predictive understanding of many spreading processes in natural populations. We present a simple iterative scaling approximation supported by simulations and rigorous bounds that accurately predicts evolutionary spread, which is determined by a trade-off between frequency and potential effectiveness of long-distance jumps. In contrast to the exponential laws predicted by deterministic "mean-field" approximations, we show that the asymptotic spatial growth is according to either a power law or a stretched exponential, depending on the tails of the dispersal kernel. More importantly, we provide a full time-dependent description of the convergence to the asymptotic behavior, which can be anomalously slow and is relevant even for long times. Our results also apply to spreading dynamics on networks with a spectrum of long-range links under certain conditions on the probabilities of long-distance travel: These are relevant for the spread of epidemics.

  5. Dynamics of the chain of forced oscillators with long-range interaction: From synchronization to chaos

    NASA Astrophysics Data System (ADS)

    Zaslavsky, G. M.; Edelman, M.; Tarasov, V. E.

    2007-12-01

    We consider a chain of nonlinear oscillators with long-range interaction of the type 1/l1+α, where l is a distance between oscillators and 0<α<2. In the continuous limit, the system's dynamics is described by a fractional generalization of the Ginzburg-Landau equation with complex coefficients. Such a system has a new parameter α that is responsible for the complexity of the medium and that strongly influences possible regimes of the dynamics, especially near α =2 and α =1. We study different spatiotemporal patterns of the dynamics depending on α and show transitions from synchronization of the motion to broad-spectrum oscillations and to chaos.

  6. Induced Long-Range Attractive Potentials of Human Serum Albumin by Ligand Binding

    SciTech Connect

    Sato, Takaaki; Komatsu, Teruyuki; Nakagawa, Akito; Tsuchida, Eishun

    2007-05-18

    Small-angle x-ray scattering and dielectric spectroscopy investigation on the solutions of recombinant human serum albumin and its heme hybrid revealed that heme incorporation induces a specific long-range attractive potential between protein molecules. This is evidenced by the enhanced forward intensity upon heme binding, despite no hindrance to rotatory Brownian motion, unbiased colloid osmotic pressure, and discontiguous nearest-neighbor distance, confirming monodispersity of the proteins. The heme-induced potential may play a trigger role in recognition of the ligand-filled human serum albumins in the circulatory system.

  7. DIII-D tokamak long range plan. Revision 3

    SciTech Connect

    1992-08-01

    The DIII-D Tokamak Long Range Plan for controlled thermonuclear magnetic fusion research will be carried out with broad national and international participation. The plan covers: (1) operation of the DIII-D tokamak to conduct research experiments to address needs of the US Magnetic Fusion Program; (2) facility modifications to allow these new experiments to be conducted; and (3) collaborations with other laboratories to integrate DIII-D research into the national and international fusion programs. The period covered by this plan is 1 November 19983 through 31 October 1998.

  8. Anisotropic blockade using pendular long-range Rydberg molecules

    NASA Astrophysics Data System (ADS)

    Eiles, Matthew T.; Lee, Hyunwoo; Pérez-Ríos, Jesús; Greene, Chris H.

    2017-05-01

    We propose an experiment to demonstrate a blockade mechanism caused by long-range anisotropic interactions in an ultracold dipolar gas composed of the recently observed "butterfly" Rydberg molecules. At the blockade radius, the strong intermolecular interaction between two adjacent molecules shifts their molecular states out of resonance with the photoassociation laser, preventing their simultaneous excitation. When the molecules are prepared in a quasi-one-dimensional (Q1D) trap, the interaction's strength can be tuned via a weak external field. The molecular density thus depends strongly on the angle between the trap axis and the field. The available Rydberg and internal molecular states provide a wide range of tunability.

  9. A Long Range Science Rover For Future Mars Missions

    NASA Technical Reports Server (NTRS)

    Hayati, Samad

    1997-01-01

    This paper describes the design and implementation currently underway at the Jet Propulsion Laboratory of a long range science rover for future missions to Mars. The small rover prototype, called Rocky 7, is capable of long traverse. autonomous navigation. and science instrument control, carries three science instruments, and can be commanded from any computer platform and any location using the World Wide Web. In this paper we describe the mobility system, the sampling system, the sensor suite, navigation and control, onboard science instruments. and the ground command and control system.

  10. INEL D&D Long-Range Plan

    SciTech Connect

    Buckland, R.J.; Kenoyer, D.J.; Preussner, D.H.

    1993-10-01

    This Long-Range Plan presents the Decontamination and Decommissioning (D&D) Program planning status for facilities at the Idaho National Engineering Laboratory (INEL). The plan provides a general description of the D&D Program objectives, management criteria, and philosophy; discusses current activities; and documents the INEL D&D Program cost and schedule estimate projections for the next 15 years. appendices are included that provide INEL D&D project historical information and a comprehensive descriptive summary of each current surplus facility.

  11. Long-range Prediction of Examining Room Requirements

    PubMed Central

    Sumner, Andrew T.; Hsieh, Richard K. C.

    1972-01-01

    A quantitative methodology for predicting long-range examining room requirements of an orthopedic outpatient clinic is described. A simulation model of the clinic is used in an analysis of the sensitivity of four performance measures to changes in the clinic components, providing upper and lower boundaries for the component values and ranking the components by their importance. Regression equations relate the number of examining rooms to the performance measures, and an overall equation is constructed to predict examining room requirements as a function of weights assigned to the four measures. PMID:5072861

  12. ATHLETE Mobility Performance in Long-Range Traverse

    NASA Technical Reports Server (NTRS)

    Townsend, Julie

    2011-01-01

    The All-Terrain Hex-Limbed Extra-Terrestrial Explorer (ATHLETE) is a modular mobility and manipulation platform being developed to support NASA operations in a variety of missions, including exploration of planetary surfaces. The agile system consists of a symmetrical arrangement of six limbs, each with seven articulated degrees of freedom and a powered wheel. This design enables transport of bulky payloads over a wide range of terrains and is envisioned as a tool to mobilize habitats, power-generation equipment, and other supplies for long-range exploration and outpost construction.

  13. INEL D&D long-range plan

    SciTech Connect

    Buckland, R.J.; Kenoyer, D.J.; LaBuy, S.A.

    1995-09-01

    This Long-Range Plan presents the Decontamination and Dismantlement (D&D) Program planning status for facilities at the Idaho National Engineering Laboratory (INEL). The plan provides a general description of the D&D Program objectives, management criteria, and policy; discusses current activities; and documents the INEL D&D Program cost and schedule estimate projections for the next 15 years. Appendices are included that provide INEL D&D project historical information, a comprehensive descriptive summary of each current D&D surplus facility, and a summary database of all INEL contaminated facilities awaiting or undergoing the facility transition process.

  14. Application of advanced technology to future long-range aircraft

    NASA Technical Reports Server (NTRS)

    Schrader, O. E.

    1976-01-01

    An assessment is presented of three separate programs that have incorporated advanced technology into the design of long-range passenger and cargo aircraft. The first technology centers around the use of a span-loaded cargo aircraft with the payload distributed along the wing. The second technology is the application of laminar flow control to the aircraft to reduce the aerodynamic drag. The last program evaluates the production of alternate aircraft fuels from coal and the use of liquid hydrogen as an aircraft fuel.

  15. Restricted Boltzmann machines for the long range Ising models

    NASA Astrophysics Data System (ADS)

    Aoki, Ken-Ichi; Kobayashi, Tamao

    2016-12-01

    We set up restricted Boltzmann machines (RBM) to reproduce the long range Ising (LRI) models of the Ohmic type in one dimension. The RBM parameters are tuned by using the standard machine learning procedure with an additional method of configuration with probability (CwP). The quality of resultant RBM is evaluated through the susceptibility with respect to the magnetic external field. We compare the results with those by block decimation renormalization group (BDRG) method, and our RBM clear the test with satisfactory precision.

  16. Passive vibration isolation for long range aerial reconnaissance systems

    NASA Astrophysics Data System (ADS)

    Otoole, J.

    1980-01-01

    The paper discusses an approach to the design of a passive isolation system for a high-altitude, long-range oblique reconnaissance camera which works in conjunction with the active, gyro-stabilized system to attenuate a broad spectrum of vibratory inputs. The proposed design provides an elastic suspension system with minimum damping forces and a damping system which controls the excursions of the camera in the resonant region of disturbance; it has both spring and damping forces in complete balance about the center of gravity of the camera. Mathematical equations and definition in support of the proposed approach are presented together with some pertinent data.

  17. Hysteresis of long-range ordering in CuAu

    SciTech Connect

    Chalupa, B.; Chmelik, F.; Sima, V.; Sprusil, B.; Spanl, M.; Lang, H.; Pfeiler, W.

    1996-12-31

    The effect of heating and cooling on the long-range order transformation in stoichiometric CuAu is investigated by several complementary measuring methods. Measurements of heat flow, resistometry and acoustic emission are done dynamically by linear heating/cooling. It is shown that measuring dynamically yields the expected effect of undercooling, which decreases with decreasing cooling rate. The dependence of undercooling on cooling rate is compared with the concept of continuous cooling for glass forming. A small influence of heating rate on disordering temperature is reported (retro-effect).

  18. The design of a long range megatransport aircraft

    NASA Technical Reports Server (NTRS)

    Weisshaar, T. A.; Layton, J. B.; Allen, C. L.

    1993-01-01

    Megatransport objectives and constraints are briefly reviewed, and certain solutions developed by student design teams at Perdue University are summarized. Particular attention is given to the market needs and the economic risks involved in such a project; and the different approaches taken to solve the problem and difficulties faced by the design teams. A long range megatransport aircraft is aimed at carrying more than 600 passengers at reduced cost, and at the same time, reducing airport and airway congestion. The design effort must take into account airport terminal facilities; passenger loading and unloading; and defeating the 'square-cube' law to design large structures.

  19. Long-range attraction of particles adhered to lipid vesicles

    NASA Astrophysics Data System (ADS)

    Sarfati, Raphael; Dufresne, Eric R.

    2016-07-01

    Many biological systems fold thin sheets of lipid membrane into complex three-dimensional structures. This microscopic origami is often mediated by the adsorption and self-assembly of proteins on a membrane. As a model system to study adsorption-mediated interactions, we study the collective behavior of micrometric particles adhered to a lipid vesicle. We estimate the colloidal interactions using a maximum likelihood analysis of particle trajectories. When the particles are highly wrapped by a tense membrane, we observe strong long-range attractions with a typical binding energy of 150 kBT and significant forces extending a few microns.

  20. Hydrogen Atoms Cause Long-Range Electronic Effects on Graphite

    NASA Astrophysics Data System (ADS)

    Ruffieux, P.; Gröning, O.; Schwaller, P.; Schlapbach, L.; Gröning, P.

    2000-05-01

    We report on long-range electronic effects caused by hydrogen-carbon interaction at the graphite surface. Two types of defects could be distinguished with a combined mode of scanning tunneling microscopy and atomic force microscopy: chemisorption of hydrogen on the basal plane of graphite and atomic vacancy formation. Both types show a \\(3×3\\)R30° superlattice in the local density of states but have a different topographic structure. The range of modifications in the electronic structure, of fundamental importance for electronic devices based on carbon nanostructures, has been found to be of the order of 20-25 lattice constants.

  1. Political Mechanisms for Long-Range Survival and Development

    NASA Astrophysics Data System (ADS)

    Marshall, W.

    As the first species aware of extinction and capable of proactively ensuring our long-term survival and development, it is striking that we do not do so with the rigor, formality, and foresight it requires. Only from a reactive posture have we responded to the challenges of global warfare, human rights, environmental concerns, and sustainable development. Despite our awareness of the possibility for extinction and apocalyptic set-backs to our evolution, and despite the existence of long-range studies-which must still be dramatically increased-proactive global policy implementation regarding our long-term survival and development is arguably non-existent. This lack of long-term policy making can be attributed in part to the lack of formal political mechanisms to facilitate longer-range policy making that extends 30 years or more into the future. Political mechanisms for infusing long-range thinking, research, and strategic planning into the policy-making process can help correct this shortcoming and provide the motivation needed to adequately address long-term challenges with the political rigor required to effectively establish and implement long-term policies. There are some efforts that attempt to address longer-range issues, but those efforts often do not connect to the political process, do not extend 30 or more years into the future, are not well-funded, and are not sufficiently systemic. Political mechanisms for long-range survival and prosperity could correct these inadequacies by raising awareness, providing funding, and most importantly, leveraging political rigor to establish and enforce long-range strategic planning and policies. The feasibility of such mechanisms should first be rigorously studied and assessed in a feasibility study, which could then inform implementation. This paper will present the case for such a study and suggest some possible political mechanisms that should be investigated further in the proposed study. This work is being further

  2. Long Range Transport of War-Related Burn Casualties

    DTIC Science & Technology

    2008-02-01

    ted to the Army’s burn center between March 2003 and February 2007. Data in- cluded total body surface area (TBSA) burn, ventilatory status... total body surface area (range, ə%–95%) with a mean Injury Severity Score of 12.2 13.7. One hundred eight-one (33.5%) casualties required venti...Long Range Transport of War-Related Burn Casualties 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT

  3. The long range transport of sulfurous aerosol to Scandinavia

    SciTech Connect

    Ottar, B.

    1980-01-01

    Results of the LRTAP program and other European studies are discussed which show that considerable long-range transport of air pollutants from the UK and central Europe to Scandinavia occurs. Data are examined which reveal that the sulfate deposition pattern in Scandinavia is largely governed by precipitation and wind direction and that sulfates deposition reaches maximum values of 3 to 5 metric tons/sq km in southern Scandinavia. The contribution from precipitation is found to outweigh the dry deposition, particularly in southern Norway.

  4. Coherent long-range thermoelectrics in nonadiabatic driven quantum systems

    NASA Astrophysics Data System (ADS)

    Gallego-Marcos, F.; Platero, G.

    2017-02-01

    We investigate direct energy and heat transfer between two distant sites of a triple quantum dot connected to reservoirs, where one of the edge dots is driven by an ac-gate voltage. We theoretically propose how to implement heat and cooling engines mediated by long-range photoassisted transport. Additionally, we propose a simple setup to heat up coherently the two reservoirs symmetrically and a mechanism to store energy in the closed system. The present proposals can be experimentally implemented and easily controlled by tuning the external parameters.

  5. ATHLETE Mobility Performance in Long-Range Traverse

    NASA Technical Reports Server (NTRS)

    Townsend, Julie

    2011-01-01

    The All-Terrain Hex-Limbed Extra-Terrestrial Explorer (ATHLETE) is a modular mobility and manipulation platform being developed to support NASA operations in a variety of missions, including exploration of planetary surfaces. The agile system consists of a symmetrical arrangement of six limbs, each with seven articulated degrees of freedom and a powered wheel. This design enables transport of bulky payloads over a wide range of terrains and is envisioned as a tool to mobilize habitats, power-generation equipment, and other supplies for long-range exploration and outpost construction.

  6. Anisotropic blockade using pendular long-range Rydberg molecules

    NASA Astrophysics Data System (ADS)

    Eiles, M. T.; Lee, H.; Pérez-Ríos, J.; Greene, C. H.

    2017-07-01

    We propose an experiment to demonstrate a novel blockade mechanism caused by long-range anisotropic interactions in an ultracold dipolar gas composed of the recently observed "butterfly" Rydberg molecules. At the blockade radius, the strong intermolecular interaction between two adjacent molecules shifts their molecular states out of resonance with the photoassociation laser, preventing their simultaneous excitation. When the molecules are prepared in a quasi-one-dimensional (Q1D) trap, the interaction's strength can be tuned via a weak external field. The molecular density thus depends strongly on the angle between the trap axis and the field. The available Rydberg and molecular states provide a wide range of tunability.

  7. Long-range exchange interaction between magnetic impurities in graphene

    NASA Astrophysics Data System (ADS)

    Agarwal, M.; Mishchenko, E. G.

    2017-02-01

    The effective spin exchange RKKY coupling between impurities (adatoms) on graphene mediated by conduction electrons is studied as a function of the strength of the potential part of the on-site energy U of the electron-adatom interaction. With increasing U , the exchange coupling becomes long range, determined largely by the impurity levels with energies close to the Dirac points. When adatoms reside on opposite sublattices, their exchange coupling, normally antiferromagnetic, becomes ferromagnetic and resonantly enhanced at a specific distance where an impurity level crosses the Dirac point.

  8. Self-Consistent Solution for the Annihilation-Diffusion Problem with Long-Range Interactions

    NASA Astrophysics Data System (ADS)

    Ginzburg, Valeriy V.

    1996-03-01

    We study the kinetics of the two-species annihilation A + B arrow 0. It is known that in the absense of long-range forces, particle density decays with time as t^-ν, with ν = d/4, d < 4, and ν = 1, d > 4 footnote D. Toussaint and F. Wilczek, J. Chem. Phys. 78, 2642 (1983). In the presence of long-range power-law forces, annihilation kinetics becomes more complicated, and exact solution is not known. Scaling theories of such systems were proposed recently, in which decay exponent was calculated based on the motion of an individual particle footnote V. Ginzburg, P. Beale, and N. A. Clark, Phys. Rev. E 52, 2583 (1995) footnote Y. Ispolatov, P. Krapivsky, Phys. Rev. E, in press. Here we derive hydrodynamic equations of evolution for a system with arbitrary power-law interaction and find self-consistent asymptotic solutions for the limit of large t. For the first time, all three factors - annihilation, diffusion and long-range forces - are accounted for. The solution is consistent with Toussaint-Wilczek and Ispolatov-Krapivsky results for non-interacting and Coulombic systems, respectively; it agrees with earlier speculations that! for Coulombic systems, mean-field annihilation exponent 1 is valid for any system dimensionality d > 1. To judge the validity of the obtained solution for intermediate power-laws, more computational data is required.

  9. Long-range synchrony and emergence of neural reentry

    PubMed Central

    Keren, Hanna; Marom, Shimon

    2016-01-01

    Neural synchronization across long distances is a functionally important phenomenon in health and disease. In order to access the basis of different modes of long-range synchrony, we monitor spiking activities over centimetre scale in cortical networks and show that the mode of synchrony depends upon a length scale, λ, which is the minimal path that activity should propagate through to find its point of origin ready for reactivation. When λ is larger than the physical dimension of the network, distant neuronal populations operate synchronously, giving rise to irregularly occurring network-wide events that last hundreds of milliseconds to several seconds. In contrast, when λ approaches the dimension of the network, a continuous self-sustained reentry propagation emerges, a regular seizure-like mode that is marked by precise spatiotemporal patterns (‘synfire chains’) and may last many minutes. Termination of a reentry phase is preceded by a decrease of propagation speed to a halt. Stimulation decreases both propagation speed and λ values, which modifies the synchrony mode respectively. The results contribute to the understanding of the origin and termination of different modes of neural synchrony as well as their long-range spatial patterns, while hopefully catering to manipulation of the phenomena in pathological conditions. PMID:27874019

  10. Phase transitions in simplified models with long-range interactions

    NASA Astrophysics Data System (ADS)

    Rocha Filho, T. M.; Amato, M. A.; Mello, B. A.; Figueiredo, A.

    2011-10-01

    We study the origin of phase transitions in several simplified models with long-range interactions. For the self-gravitating ring model, we are unable to observe a possible phase transition predicted by Nardini and Casetti [Phys. Rev. EPLEEE81539-375510.1103/PhysRevE.80.060103 80, 060103R (2009).] from an energy landscape analysis. Instead we observe a sharp, although without any nonanalyticity, change from a core-halo to a core-only configuration in the spatial distribution functions for low energies. By introducing a different class of solvable simplified models without any critical points in the potential energy we show that a behavior similar to the thermodynamics of the ring model is obtained, with a first-order phase transition from an almost homogeneous high-energy phase to a clustered phase and the same core-halo to core configuration transition at lower energies. We discuss the origin of these features for the simplified models and show that the first-order phase transition comes from the maximization of the entropy of the system as a function of energy and an order parameter, as previously discussed by Hahn and Kastner [Phys. Rev. EPLEEE81539-375510.1103/PhysRevE.72.056134 72, 056134 (2005); Eur. Phys. J. BEPJBFY1434-602810.1140/epjb/e2006-00100-7 50, 311 (2006)], which seems to be the main mechanism causing phase transitions in long-range interacting systems.

  11. Long-range response in ac electricity grids

    NASA Astrophysics Data System (ADS)

    Jung, Daniel; Kettemann, Stefan

    2016-07-01

    Local changes in the topology of electricity grids can cause overloads far away from the disturbance [D. Witthaut and M. Timme, Eur. Phys. J. B 86, 377 (2013), 10.1140/epjb/e2013-40469-4], making the prediction of the robustness against changes in the topology—for example, caused by power outages or grid extensions—a challenging task. The impact of single-line additions on the long-range response of dc electricity grids has recently been studied [D. Labavić, R. Suciu, H. Meyer-Ortmanns, and S. Kettemann, Eur. Phys. J.: Spec. Top. 223, 2517 (2014), 10.1140/epjst/e2014-02273-0]. By solving the real part of the static ac load flow equations, we conduct a similar investigation for ac grids. In a regular two-dimensional grid graph with cyclic boundary conditions, we find a power law decay for the change of power flow as a function of distance to the disturbance over a wide range of distances. The power exponent increases and saturates for large system sizes. By applying the same analysis to the German transmission grid topology, we show that also in real-world topologies a long-ranged response can be found.

  12. Disordered Kitaev chains with long-range pairing

    NASA Astrophysics Data System (ADS)

    Cai, Xiaoming

    2017-03-01

    We study the competition of disorder and superconductivity for a generalized Kitaev model in incommensurate potentials. The generalized Kitaev model describes one dimensional spinless fermions with long-range p-wave superconducting pairing, which decays with distance l as a power law  ∼1/{{l}α} . We focus on the transition from the topological superconducting phase to the topologically trivial Anderson localized phase, and effects of the exponent α on this phase transition. In the topological superconducting phase, for a system under open boundary condition the amplitude of zero-mode Majorana fermion has a hybrid exponential-algebraic decay as the distance increases from the edge. In the Anderson localized phase, some single-particle states remain critical for very strong disorders and the number of critical states increases as α decreases. In addition, except for critical disorders, the correlation function always has an exponential decay at the short range and an algebraic decay at the long range. Phase transition points are also numerically determined and the topological phase transition happens earlier at a smaller disorder strength for a system with smaller α.

  13. Dolphin "packet" use during long-range echolocation tasks.

    PubMed

    Finneran, James J

    2013-03-01

    When echolocating, dolphins typically emit a single broadband "click," then wait to receive the echo before emitting another click. However, previous studies have shown that during long-range echolocation tasks, they may instead emit a burst, or "packet," of several clicks, then wait for the packet of echoes to return before emitting another packet of clicks. The reasons for the use of packets are unknown. In this study, packet use was examined by having trained bottlenose dolphins perform long-range echolocation tasks. The tasks featured "phantom" echoes produced by capturing the dolphin's outgoing echolocation clicks, convolving the clicks with an impulse response to create an echo waveform, and then broadcasting the delayed, scaled echo to the dolphin. Dolphins were trained to report the presence of phantom echoes or a change in phantom echoes. Target range varied from 25 to 800 m. At ranges below 75 m, the dolphins rarely used packets. As the range increased beyond 75 m, two of the three dolphins increasingly produced packets, while the third dolphin instead utilized very high click repetition rates. The use of click packets appeared to be governed more by echo delay (target range) than echo amplitude.

  14. Helioseismology with long-range dark matter-baryon interactions

    SciTech Connect

    Lopes, Ilídio; Panci, Paolo; Silk, Joseph E-mail: panci@iap.fr

    2014-11-10

    Assuming the existence of a primordial asymmetry in the dark sector, we study how long-range dark matter (DM)-baryon interactions, induced by the kinetic mixing of a new U(1) gauge boson and a photon, affect the evolution of the Sun and, in turn, the sound speed the profile obtained from helioseismology. Thanks to the explicit dependence on the exchanged momenta in the differential cross section (Rutherford-like scattering), we find that DM particles with a mass of ∼10 GeV, kinetic mixing parameter of the order of 10{sup –9}, and a mediator with a mass smaller than a few MeV improve the agreement between the best solar model and the helioseismic data without being excluded by direct detection experiments. In particular, the LUX detector will soon be able to either constrain or confirm our best-fit solar model in the presence of a dark sector with long-range interactions that reconcile helioseismology with thermal neutrino results.

  15. Emergent long-range magnetic ordering in manganite superlattices

    NASA Astrophysics Data System (ADS)

    Burganov, Bulat; Macke, Sebastian; Monkman, Eric; Adamo, Carolina; Shai, Daniel; Schlom, Darrell; Sawatzky, George; Shen, Kyle

    2015-03-01

    Complex oxides composed into atomically precise heterostructures host a plethora of new phenomena driven by interface effects, dimensionality, correlations and strain. An example is emergent ferromagnetism in the superlattices (SL) of LaMnO3/SrMnO3 and the dimensionality-driven metal insulator transition, still not well understood theoretically. We use soft x-ray scattering combined with SQUID magnetometry to determine the magnetic and orbital ordering in the (LaMnO3)2n /(SrMnO3)n SL for n =1,2,3,4. By composition this system is close to colossal-magnetoresistive La2/3Sr1/3MnO3, an FM metal below 400K. The system undergoes a metal-insulator transition with higher n and is believed to have a complex magnetic ordering. We observe an unexpected long-range order in the n =4 sample where the magnetic period is equal to two chemical periods. The observed half-order Bragg peaks show strong linear and no circular dichroism. The temperature and polarization dependence of reflectometry points towards alignment between A-type AFM orders in the neighboring LaMnO3 layers, which is very unusual and indicates a long range interaction acting across the thick SrMnO3 layers with nominally G-type spin configuration. We simulate the reflectometry data for several model spin configurations to further elucidate the nature of this ordering.

  16. Long-range response in ac electricity grids.

    PubMed

    Jung, Daniel; Kettemann, Stefan

    2016-07-01

    Local changes in the topology of electricity grids can cause overloads far away from the disturbance [D. Witthaut and M. Timme, Eur. Phys. J. B 86, 377 (2013)EPJBFY1434-602810.1140/epjb/e2013-40469-4], making the prediction of the robustness against changes in the topology-for example, caused by power outages or grid extensions-a challenging task. The impact of single-line additions on the long-range response of dc electricity grids has recently been studied [D. Labavić, R. Suciu, H. Meyer-Ortmanns, and S. Kettemann, Eur. Phys. J.: Spec. Top. 223, 2517 (2014)1951-635510.1140/epjst/e2014-02273-0]. By solving the real part of the static ac load flow equations, we conduct a similar investigation for ac grids. In a regular two-dimensional grid graph with cyclic boundary conditions, we find a power law decay for the change of power flow as a function of distance to the disturbance over a wide range of distances. The power exponent increases and saturates for large system sizes. By applying the same analysis to the German transmission grid topology, we show that also in real-world topologies a long-ranged response can be found.

  17. Coping With Climate Noise: Long Range Dependence and Weather Derivatives

    NASA Astrophysics Data System (ADS)

    Jewson, S.; Caballero, R.

    2002-12-01

    Random day-to-day changes in weather lead to random year-to-year fluctuations in monthly and seasonal means, a feature known as "climate noise". Such climate noise has direct economic impact on a wide variety of businesses. A typical example is energy vendors, whose annual revenues are closely correlated with seasonal mean temperatures. To deal with this risk, a form of insurance known as weather derivatives has been developed in recent years. We discuss a Monte Carlo approach to the pricing of weather derivatives based on stochastic modeling of daily temperature. It will be shown that this approach can only be succesful if the time-series model correctly captures the autocorrelation structure of the data even at very high lags. Evidence will be presented that observed daily temperatures exhibit long-range dependence, i.e. power-law decay of the autocorrelation. This means that classical Box-Jenkins ARMA models are unequal to the task, since their autocorrelations decay exponentially. A generalisation of ARMA models which explicitly includes long-range dependence does however prove to be suitable, at least in some cases. We also briefly discuss the physical mechanisms which give rise to the long memory found in the data.

  18. Surface tension and long range corrections of cylindrical interfaces.

    PubMed

    Bourasseau, E; Malfreyt, P; Ghoufi, A

    2015-12-21

    The calculation of the surface tension of curved interfaces has been deeply investigated from molecular simulation during this last past decade. Recently, the thermodynamic Test-Area (TA) approach has been extended to the calculation of surface tension of curved interfaces. In the case of the cylindrical vapour-liquid interfaces of water and Lennard-Jones fluids, it was shown that the surface tension was independent of the curvature of the interface. In addition, the surface tension of the cylindrical interface is higher than that of the planar interface. Molecular simulations of cylindrical interfaces have been so far performed (i) by using a shifted potential, (ii) by means of large cutoff without periodic boundary conditions, or (iii) by ignoring the long range corrections to the surface tension due to the difficulty to estimate them. Indeed, unlike the planar interfaces there are no available operational expressions to consider the tail corrections to the surface tension of cylindrical interfaces. We propose here to develop the long range corrections of the surface tension for cylindrical interfaces by using the non-exponential TA (TA2) method. We also extend the formulation of the Mecke-Winkelmann corrections initially developed for planar surfaces to cylindrical interfaces. We complete this study by the calculation of the surface tension of cylindrical surfaces of liquid tin and copper using the embedded atom model potentials.

  19. Surface tension and long range corrections of cylindrical interfaces

    SciTech Connect

    Bourasseau, E.; Ghoufi, A.

    2015-12-21

    The calculation of the surface tension of curved interfaces has been deeply investigated from molecular simulation during this last past decade. Recently, the thermodynamic Test-Area (TA) approach has been extended to the calculation of surface tension of curved interfaces. In the case of the cylindrical vapour-liquid interfaces of water and Lennard-Jones fluids, it was shown that the surface tension was independent of the curvature of the interface. In addition, the surface tension of the cylindrical interface is higher than that of the planar interface. Molecular simulations of cylindrical interfaces have been so far performed (i) by using a shifted potential, (ii) by means of large cutoff without periodic boundary conditions, or (iii) by ignoring the long range corrections to the surface tension due to the difficulty to estimate them. Indeed, unlike the planar interfaces there are no available operational expressions to consider the tail corrections to the surface tension of cylindrical interfaces. We propose here to develop the long range corrections of the surface tension for cylindrical interfaces by using the non-exponential TA (TA2) method. We also extend the formulation of the Mecke-Winkelmann corrections initially developed for planar surfaces to cylindrical interfaces. We complete this study by the calculation of the surface tension of cylindrical surfaces of liquid tin and copper using the embedded atom model potentials.

  20. Long-range synchrony and emergence of neural reentry

    NASA Astrophysics Data System (ADS)

    Keren, Hanna; Marom, Shimon

    2016-11-01

    Neural synchronization across long distances is a functionally important phenomenon in health and disease. In order to access the basis of different modes of long-range synchrony, we monitor spiking activities over centimetre scale in cortical networks and show that the mode of synchrony depends upon a length scale, λ, which is the minimal path that activity should propagate through to find its point of origin ready for reactivation. When λ is larger than the physical dimension of the network, distant neuronal populations operate synchronously, giving rise to irregularly occurring network-wide events that last hundreds of milliseconds to several seconds. In contrast, when λ approaches the dimension of the network, a continuous self-sustained reentry propagation emerges, a regular seizure-like mode that is marked by precise spatiotemporal patterns (‘synfire chains’) and may last many minutes. Termination of a reentry phase is preceded by a decrease of propagation speed to a halt. Stimulation decreases both propagation speed and λ values, which modifies the synchrony mode respectively. The results contribute to the understanding of the origin and termination of different modes of neural synchrony as well as their long-range spatial patterns, while hopefully catering to manipulation of the phenomena in pathological conditions.

  1. The ORNL Surplus Facilities Management Program Long Range Plan

    SciTech Connect

    Myrick, T.E.

    1984-09-01

    The Surplus Facilities Management Program (SFMP) at Oak Ridge National Laboratory (ORNL) is part of the Department of Energy`s (DOE) National SFMP, administered by the Richland Operations Office. This program was established to provide for the management of DOE surplus radioactively contaminated facilities from the end of their operating life until final facility disposition is completed. As part of this program, the ORNL SFMP oversees some 76 individual surplus facilities, ranging in complexity from abandoned waste storage tanks to large experimental reactors. The ORNL SFMP has prepared this Long Range Plan to outline the long-term management strategy for those facilities included in the program. The primary objective of this plan are to: (1) develop a base of information for each ORNL SFMP facility, (2) conduct preliminary decommissioning analyses to identify feasible alternatives, (3) assess the current and future risk of each facility, (4) establish a priority list for the decommissioning projects, and (5) integrate the individual project costs and schedules into an overall program schedule and cost estimate for the ORNL site. The Long Range Plan also provides an overview of the ORNL SFMP management structure, specifies the decommissioning criteria to be employed, and identifies special technical problems, research and development needs, and special facilities and equipment that may be required for decommissioning operations.

  2. One-dimensional long-range percolation: A numerical study

    NASA Astrophysics Data System (ADS)

    Gori, G.; Michelangeli, M.; Defenu, N.; Trombettoni, A.

    2017-07-01

    In this paper we study bond percolation on a one-dimensional chain with power-law bond probability C /rd +σ , where r is the distance length between distinct sites and d =1 . We introduce and test an order-N Monte Carlo algorithm and we determine as a function of σ the critical value Cc at which percolation occurs. The critical exponents in the range 0 <σ <1 are reported. Our analysis is in agreement, up to a numerical precision ≈10-3 , with the mean-field result for the anomalous dimension η =2 -σ , showing that there is no correction to η due to correlation effects. The obtained values for Cc are compared with a known exact bound, while the critical exponent ν is compared with results from mean-field theory, from an expansion around the point σ =1 and from the ɛ -expansion used with the introduction of a suitably defined effective dimension deff relating the long-range model with a short-range one in dimension deff. We finally present a formulation of our algorithm for bond percolation on general graphs, with order N efficiency on a large class of graphs including short-range percolation and translationally invariant long-range models in any spatial dimension d with σ >0 .

  3. Reservoir shore development in long range terrestrial laser scanning monitoring.

    NASA Astrophysics Data System (ADS)

    Kaczmarek, Halina

    2016-04-01

    Shore zones of reservoirs are in most cases very active, getting transformed as a result of coastal processes and mass movements initiated on the slopes surrounding the reservoir. From the point of view of the users of water reservoirs shore recession strongly undesirable as it causes destruction to infrastructure and buildings located in the immediate vicinity of the reservoir. For this reason, reservoir shores require continuous geodetic monitoring. Fast and accurate geodetic measurements covering shore sections several kilometers long, often in poorly accessible areas, are available using long range terrestrial laser scanning (TLS). The possibilities of using long range terrestrial laser scanning are shown on the example of the reservoir Jeziorsko on the Warta River (Central Poland). This reservoir, created in the years 1986-1992, is a typical retention reservoir, the annual fluctuations of which reach 5 m. Depending on the water level its surface area ranges from 42.3 to 19.6 km2. The width of the reservoir is 2.5 km. The total shore length of the reservoir, developed in Quaternary till and sand-till sediments, is 44.3 km, including 30.1 km of the unreinforced shore. Out of the unreinforced shore 27% is subject to coastal erosion. The cliff heights vary from a few cm to 12.5 meters, and the current rate of the cliff recession ranges from 0 to 1.12 m/y. The study used a terrestrial long range laser scanner Riegl VZ-4000 of a range of up to 4000 m. It enabled conducting the measurements of the cliff recession from the opposite shore of the reservoir, with an angular resolution of 0.002°, which gives about 50 measurement points per 1 m2. The measurements were carried out in the years 2014-2015, twice a year, in early spring before high water level, and in late autumn at a dropping water level. This allowed the separation of the impact of coastal processes and frost weathering on the cliff recession and their quantitative determination. The size and nature of

  4. Long-range Acoustic Interactions in Insect Swarms: An Adaptive Gravity Model

    NASA Astrophysics Data System (ADS)

    Gorbonos, Dan; Ianconescu, Reuven; Puckett, James G.; Ni, Rui; Ouellette, Nicholas T.; Gov, Nir S.

    The collective motion of groups of animals emerges from the net effect of the interactions between individual members of the group. In many cases, such as birds, fish, or ungulates, these interactions are mediated by sensory stimuli that predominantly arise from nearby neighbors. But not all stimuli in animal groups are short range. Here, we consider mating swarms of midges, which interact primarily via long-range acoustic stimuli. We exploit the similarity in form between the decay of acoustic and gravitational sources to build a model for swarm behavior. By accounting for the adaptive nature of the midges' acoustic sensing, we show that our ``adaptive gravity'' model makes mean-field predictions that agree well with experimental observations of laboratory swarms. Our results highlight the role of sensory mechanisms and interaction range in collective animal behavior. The adaptive interactions that we present here open a new class of equations of motion, which may appear in other biological contexts.

  5. Experiences from long range passive and active imaging

    NASA Astrophysics Data System (ADS)

    Grönwall, Christina; Gustafsson, David; Steinvall, Ove; Tolt, Gustav

    2015-10-01

    We present algorithm evaluations for ATR of small sea vessels. The targets are at km distance from the sensors, which means that the algorithms have to deal with images affected by turbulence and mirage phenomena. We evaluate previously developed algorithms for registration of 3D-generating laser radar data. The evaluations indicate that some robustness to turbulence and mirage induced uncertainties can be handled by our probabilistic-based registration method. We also assess methods for target classification and target recognition on these new 3D data. An algorithm for detecting moving vessels in infrared image sequences is presented; it is based on optical flow estimation. Detection of moving target with an unknown spectral signature in a maritime environment is a challenging problem due to camera motion, background clutter, turbulence and the presence of mirage. First, the optical flow caused by the camera motion is eliminated by estimating the global flow in the image. Second, connected regions containing significant motions that differ from camera motion is extracted. It is assumed that motion caused by a moving vessel is more temporally stable than motion caused by mirage or turbulence. Furthermore, it is assumed that the motion caused by the vessel is more homogenous with respect to both magnitude and orientation, than motion caused by mirage and turbulence. Sufficiently large connected regions with a flow of acceptable magnitude and orientation are considered target regions. The method is evaluated on newly collected sequences of SWIR and MWIR images, with varying targets, target ranges and background clutter. Finally we discuss a concept for combining passive and active imaging in an ATR process. The main steps are passive imaging for target detection, active imaging for target/background segmentation and a fusion of passive and active imaging for target recognition.

  6. Parallelized Stochastic Cutoff Method for Long-Range Interacting Systems

    NASA Astrophysics Data System (ADS)

    Endo, Eishin; Toga, Yuta; Sasaki, Munetaka

    2015-07-01

    We present a method of parallelizing the stochastic cutoff (SCO) method, which is a Monte-Carlo method for long-range interacting systems. After interactions are eliminated by the SCO method, we subdivide a lattice into noninteracting interpenetrating sublattices. This subdivision enables us to parallelize the Monte-Carlo calculation in the SCO method. Such subdivision is found by numerically solving the vertex coloring of a graph created by the SCO method. We use an algorithm proposed by Kuhn and Wattenhofer to solve the vertex coloring by parallel computation. This method was applied to a two-dimensional magnetic dipolar system on an L × L square lattice to examine its parallelization efficiency. The result showed that, in the case of L = 2304, the speed of computation increased about 102 times by parallel computation with 288 processors.

  7. Long range p -wave proximity effect into a disordered metal

    NASA Astrophysics Data System (ADS)

    Keser, Aydin Cem; Stanev, Valentin; Galitski, Victor

    2015-03-01

    We use quasiclassical methods of superconductivity to study the superconducting proximity effect from a topological p -wave superconductor into a disordered quasi-one-dimensional metallic wire. We demonstrate that the corresponding Eilenberger equations with disorder reduce to a closed nonlinear equation for the superconducting component of the matrix Green's function. Remarkably, this equation is formally equivalent to a classical mechanical system (i.e., Newton's equations), with the Green function corresponding to a coordinate of a fictitious particle and the coordinate along the wire corresponding to time. This mapping allows us to obtain exact solutions in the disordered nanowire in terms of elliptic functions. A surprising result that comes out of this solution is that the p -wave superconductivity proximity induced into the disordered metal remains long range, decaying as slowly as the conventional s -wave superconductivity. It is also shown that impurity scattering leads to the appearance of a zero-energy peak.

  8. Long-range effects in electron scattering by polar molecules

    NASA Astrophysics Data System (ADS)

    Fabrikant, Ilya I.

    2016-11-01

    We review long-range effects in electron collisions with polar molecules, starting with elastic scattering. We then go to rotationally and vibrationally inelastic processes and dissociative electron attachment. The last two are strongly affected by vibrational Feshbach resonances which have been observed and described theoretically in many systems from simple diatomic molecules to more complex polyatomics, biologically relevant molecules, and van der Waals clusters. We then review environmental effects which include electron interaction with molecules adsorbed on surfaces and molecules in cluster environments. We concentrate on physics rather than on listing results of ab initio calculations. With increasing complexity of targets and processes model approaches become more relevant. We demonstrate their success in the theoretical description of electron attachment to polyatomic molecules and to molecules in complex environments.

  9. Contactless nonlinear optics mediated by long-range Rydberg interactions

    NASA Astrophysics Data System (ADS)

    Busche, Hannes; Huillery, Paul; Ball, Simon W.; Ilieva, Teodora; Jones, Matthew P. A.; Adams, Charles S.

    2017-07-01

    In conventional nonlinear optics, linear quantum optics, and cavity quantum electrodynamics to create effective photon-photon interactions photons must have, at one time, interacted with matter inside a common medium. In contrast, in Rydberg quantum optics, optical photons are coherently and reversibly mapped onto collective atomic Rydberg excitations, giving rise to dipole-mediated effective photon-photon interactions that are long range. Consequently, a spatial overlap between the light modes is no longer required. We demonstrate such a contactless coupling between photons stored as collective Rydberg excitations in spatially separate optical media. The potential induced by each photon modifies the retrieval mode of its neighbour, leading to correlations between them. We measure these correlations as a function of interaction strength, distance and storage time, demonstrating an effective interaction between photons separated by 15 times their wavelength. Contactless effective photon-photon interactions are relevant for scalable multichannel photonic devices and the study of strongly correlated many-body dynamics using light.

  10. An evaluation methodology for long-range jammer to CCD

    NASA Astrophysics Data System (ADS)

    Zhang, Wen-pan; Ren, Guang-sen; Wang, Yan-bin; Li, Hua; Zhu, Rong-zhen

    2015-11-01

    By analyzing the factors of laser transmission from long-range jammer to CCD in the distribution of laser at the entrance of optical system of CCD, an evaluation methodology was established which utilized the ATP error data and the distribution of laser through turbulent atmosphere together and could get the jamming probability which could be used to get evaluation result. A conversion method was devised to convert test data to simulation data of ATP. Based on circular aperture Fraunhofer diffraction theory, a simplified model that only used the central bright patch was provided to convert the relationship between the number of saturated pixel and the incident laser energy by testing to the relationship in simulation. Some advice was given for the usage of test data of ATP and the relationship between the number of saturated pixel and the incident laser energy by testing to make sure that the data is available.

  11. Traveling solitons in long-range oscillator chains

    NASA Astrophysics Data System (ADS)

    Miloshevich, George; Nguenang, Jean Pierre; Dauxois, Thierry; Khomeriki, Ramaz; Ruffo, Stefano

    2017-03-01

    We investigate the existence and propagation of solitons in a long-range extension of the quartic Fermi–Pasta–Ulam (FPU) chain of anharmonic oscillators. The coupling in the linear term decays as a power-law with an exponent 1<α ≤slant 3 . We obtain an analytic perturbative expression of traveling envelope solitons by introducing a non linear Schrödinger equation for the slowly varying amplitude of short wavelength modes. Due to the non analytic properties of the dispersion relation, it is crucial to develop the theory using discrete difference operators. Those properties are also the ultimate reason why kink-solitons may exist but are unstable, at variance with the short-range FPU model. We successfully compare these approximate analytic results with numerical simulations for the value α =2 which was chosen as a case study.

  12. Sparse labeling of proteins: Structural characterization from long range constraints

    NASA Astrophysics Data System (ADS)

    Prestegard, James H.; Agard, David A.; Moremen, Kelley W.; Lavery, Laura A.; Morris, Laura C.; Pederson, Kari

    2014-04-01

    Structural characterization of biologically important proteins faces many challenges associated with degradation of resolution as molecular size increases and loss of resolution improving tools such as perdeuteration when non-bacterial hosts must be used for expression. In these cases, sparse isotopic labeling (single or small subsets of amino acids) combined with long range paramagnetic constraints and improved computational modeling offer an alternative. This perspective provides a brief overview of this approach and two discussions of potential applications; one involving a very large system (an Hsp90 homolog) in which perdeuteration is possible and methyl-TROSY sequences can potentially be used to improve resolution, and one involving ligand placement in a glycosylated protein where resolution is achieved by single amino acid labeling (the sialyltransferase, ST6Gal1). This is not intended as a comprehensive review, but as a discussion of future prospects that promise impact on important questions in the structural biology area.

  13. The effect of long-range interactions in DNA melting

    NASA Astrophysics Data System (ADS)

    Santos, Aaron; Klein`, William

    2014-03-01

    A theoretical understanding of the DNA melting transition may provide insight into the biological mechanisms of transcription and replication. If this process occurs via nucleation, it should exhibit several key features: metastability, rapid spontaneous growth, and droplet formation. In this talk, I describe the results of recent computational and theoretical studies on nearest-neighbor and long-range DNA models. While the models exhibit some characteristics of classical nucleation when the interaction range is short, they may undergo spinodal nucleation when the interaction range is long. In contrast to classical nucleation droplets, which are compact, spinodal critical droplets are diffuse, fractal-like, and similar to the metastable state. These results have clear implications for transcription and replication in biological DNA.

  14. Stable swarming using adaptive long-range interactions

    NASA Astrophysics Data System (ADS)

    Gorbonos, Dan; Gov, Nir S.

    2017-04-01

    Sensory mechanisms in biology, from cells to humans, have the property of adaptivity, whereby the response produced by the sensor is adapted to the overall amplitude of the signal, reducing the sensitivity in the presence of strong stimulus, while increasing it when it is weak. This property is inherently energy consuming and a manifestation of the nonequilibrium nature of living organisms. We explore here how adaptivity affects the effective forces that organisms feel due to others in the context of a uniform swarm, in both two and three dimensions. The interactions between the individuals are taken to be attractive and long-range and of power-law form. We find that the effects of adaptivity inside the swarm are dramatic, where the effective forces decrease (or remain constant) with increasing swarm density. Linear stability analysis demonstrates how this property prevents collapse (Jeans instability), when the forces are adaptive. Adaptivity therefore endows swarms with a natural mechanism for self-stabilization.

  15. Position-insensitive long range inductive power transfer

    NASA Astrophysics Data System (ADS)

    Kwan, Christopher H.; Lawson, James; Yates, David C.; Mitcheson, Paul D.

    2014-11-01

    This paper presents results of an improved inductive wireless power transfer system for reliable long range powering of sensors with milliwatt-level consumption. An ultra-low power flyback impedance emulator operating in open loop is used to present the optimal load to the receiver's resonant tank. Transmitter power modulation is implemented in order to maintain constant receiver power and to prevent damage to the receiver electronics caused by excessive received voltage. Received power is steady up to 3 m at around 30 mW. The receiver electronics and feedback system consumes 3.1 mW and so with a transmitter input power of 163.3 W the receiver becomes power neutral at 4.75 m. Such an IPT system can provide a reliable alternative to energy harvesters for supplying power concurrently to multiple remote sensors.

  16. Challenges in miniaturized automotive long-range lidar system design

    NASA Astrophysics Data System (ADS)

    Fersch, Thomas; Weigel, Robert; Koelpin, Alexander

    2017-05-01

    This paper discusses the current technical limitations posed on endeavors to miniaturize lidar systems for use in automotive applications and how to possibly extend those limits. The focus is set on long-range scanning direct time of flight LiDAR systems using APD photodetectors. Miniaturization evokes severe problems in ensuring absolute laser safety while maintaining the systems' performance in terms of maximum range, signal-to-noise ratio, detection probability, pixel density, or frame rate. Based on hypothetical but realistic specifications for an exemplary system the complete lidar signal path is calculated. The maximum range of the system is used as a general performance indicator. It is determined with the minimum signal-to-noise ratio required to detect an object. Various system parameters are varied to find their impact on the system's range. The reduction of the laser's pulse width and the right choice for the transimpedance amplifier's amplification have shown to be practicable measures to double the system's range.

  17. Long-range interactions in antiferromagnetic quantum spin chains

    NASA Astrophysics Data System (ADS)

    Bravo, B.; Cabra, D. C.; Gómez Albarracín, F. A.; Rossini, G. L.

    2017-08-01

    We study the role of long-range dipolar interactions on antiferromagnetic spin chains, from the classical S →∞ limit to the deep quantum case S =1 /2 , including a transverse magnetic field. To this end, we combine different techniques such as classical energy minima, classical Monte Carlo, linear spin waves, bosonization, and density matrix renormalization group (DMRG). We find a phase transition from the already reported dipolar ferromagnetic region to an antiferromagnetic region for high enough antiferromagnetic exchange. Thermal and quantum fluctuations destabilize the classical order before reaching magnetic saturation in both phases, and also close to zero field in the antiferromagnetic phase. In the extreme quantum limit S =1 /2 , extensive DMRG computations show that the main phases remain present with transition lines to saturation significatively shifted to lower fields, in agreement with the bosonization analysis. The overall picture maintains a close analogy with the phase diagram of the anisotropic XXZ spin chain in a transverse field.

  18. Vlasov equation for long-range interactions on a lattice.

    PubMed

    Bachelard, R; Dauxois, T; De Ninno, G; Ruffo, S; Staniscia, F

    2011-06-01

    We show that, in the continuum limit, the dynamics of Hamiltonian systems defined on a lattice with long-range couplings is well described by the Vlasov equation. This equation can be linearized around the homogeneous state, and a dispersion relation, which depends explicitly on the Fourier modes of the lattice, can be derived. This allows one to compute the stability thresholds of the homogeneous state, which turns out to depend on the mode number. When this state is unstable, the growth rates are also functions of the mode number. Explicit calculations are performed for the α-Hamiltonian mean field model with 0≤α<1, for which the mean-field mode is always found to dominate the exponential growth. The theoretical predictions are successfully compared with numerical simulations performed on a finite lattice.

  19. Effective field theory for long-range properties of bottomonium

    NASA Astrophysics Data System (ADS)

    Krein, Gastão

    2017-03-01

    In this communication we present selected results from a recent study [N. Brambilla, G. Krein, J. Tarrús Castellà and A. Vairo, Phys. Rev. D 93, 054002 (2016)] of long-range properties of bottomonium. An analytical expression for the chromopolarizability of 1S bottomonium states is derived within the framework of potential nonrelativistic QCD (pNRQCD). Next, after integrating out the ultrasoft scale associated with the binding energy of bottomonium, the QCD trace anomaly is used to obtain the two-pion production amplitude for the chromopolarizability operator and the result is matched to a chiral effective field theory having bottomonium states and pions as degrees of freedom. We present results for the leading chiral logarithm correction to the mass of the 1S bottomonium and the van der Waals potential between two bottomonium states.

  20. Mechanism of long-range proton translocation along biological membranes.

    PubMed

    Medvedev, Emile S; Stuchebrukhov, Alexei A

    2013-02-14

    Recent experiments suggest that protons can travel along biological membranes up to tens of micrometers, but the mechanism of transport is unknown. To explain such a long-range proton translocation we describe a model that takes into account the coupled bulk diffusion that accompanies the migration of protons on the surface. We show that protons diffusing at or near the surface before equilibrating with the bulk desorb and re-adsorb at the surface thousands of times, giving rise to a power-law desorption kinetics. As a result, the decay of the surface protons occurs very slowly, allowing for establishing local gradient and local exchange, as was envisioned in the early local models of biological energy transduction.

  1. Fingerprint of local disorder in long range ordered isometric pyrochlores.

    PubMed

    Martel, Laura; Naji, Mohamed; Popa, Karin; Vigier, Jean-François; Somers, Joseph

    2017-09-25

    The detailed characterization of local order and disorder in isometric A2B2O7 crystalline pyrochlores is of significant importance in view of their wide range and sensitive technological applications. Nevertheless, much remains to be understood concerning their atomic scale structures. Here we specifically pinpoint local order and disorder in four stoichiometric Ln2Zr2O7 (Ln = La, Nd, Sm and Eu) pyrochlores using a combination of three standard easily available laboratory techniques: XRD, (17)O solid-state MAS NMR and Raman spectroscopy. The evolution of the oxygen sub-lattice identifies specific features (extra (17)O NMR signals and Raman bands) which undoubtedly reveal local oxygen order and disorder in these stoichiometric long range ordered crystalline pyrochlores. These results complete the understanding of the atomic scale in these stoichiometric pyrochlores necessitating the need for new microscopic structural models.

  2. Disrupting long-range polar order with an electric field

    NASA Astrophysics Data System (ADS)

    Guo, Hanzheng; Liu, Xiaoming; Xue, Fei; Chen, Long-Qing; Hong, Wei; Tan, Xiaoli

    2016-05-01

    Electric fields are known to favor long-range polar order through the aligning of electric dipoles in relation to Coulomb's force. Therefore, it would be surprising to observe a disordered polar state induced from an ordered state by electric fields. Here we show such an unusual phenomenon in a polycrystalline oxide where electric fields induce a ferroelectric-to-relaxor phase transition. The nonergodic relaxor phase with disordered dipoles appears as an intermediate state under electric fields during polarization reversal of the ferroelectric phase. Using the phenomenological theory, the underlying mechanism for this unexpected behavior can be attributed to the slow kinetics of the ferroelectric-to-relaxor phase transition, as well as its competition against domain switching during electric reversal. The demonstrated material could also serve as a model system to study the transient stages in first-order phase transitions; the slow kinetics does not require the use of sophisticated ultrafast tools.

  3. Particle filter for long range radar in RUV

    NASA Astrophysics Data System (ADS)

    Romeo, Kevin; Willett, Peter; Bar-Shalom, Yaakov

    2014-06-01

    In this paper we present an approach for tracking with a high-bandwidth active radar in long range scenarios with 3-D measurements in r-u-v coordinates. The 3-D low-process-noise scenarios considered are much more difficult than the ones we have previously investigated where measurements were in 2-D (i.e., polar coordinates). We show that in these 3-D scenarios the extended Kalman filter and its variants are not desirable as they suffer from either major consistency problems or degraded range accuracy, and most flavors of particle filter suffer from a loss of diversity among particles after resampling. This leads to sample impoverishment and divergence of the filter. In the scenarios studied, this loss of diversity can be attributed to the very low process noise. However, a regularized particle filter is shown to avoid this diversity problem while producing consistent results. The regularization is accomplished using a modified version of the Epanechnikov kernel.

  4. Solid state long range surface plasmon polariton single mode lasers

    NASA Astrophysics Data System (ADS)

    Karami Keshmarzi, Elham; Tait, R. Niall; Berini, Pierre

    2013-10-01

    Incorporation of a solid-state gain medium in the cladding of a Long Range Surface Plasmon Polariton (LRSPP) waveguide in order to create a single-mode near-infrared laser source is proposed. LRSPP Bragg gratings based on stepping the width of the metal strip are used to form the laser's cavity. Three laser configurations are presented: The first 2 lasers employ DBRs (Distributed Bragg Reflectors) in ECL (External Cavity Laser) architecture while the third is based on the DFB (Distributed Feedback) configuration. All 3 configurations are thermally tunable by heating the gratings directly by injecting current. The lasers are convenient to fabricate leading to inexpensive sources that could be used in optical integrated circuits or waveguide biosensors.

  5. Heat Transport due to Long-Range Collisions.

    NASA Astrophysics Data System (ADS)

    Hollmann, Eric M.

    1999-11-01

    Cross-magnetic-field heat transport in a quiescent pure ion plasma is found to be diffusive, with measured thermal diffusivity \\chi which is independent of magnetic field strength B and plasma density n. The measured values of \\chi are up to 100 times larger than the ``classical'' thermal diffusivity \\chic = (16 √π / 15) (n barv b^2 ) r_c^2 ln (rc / b) ∝ n^1 B-2 T-1/2 expected from velocity-scattering collisions;(M.N. Rosenbluth et al., Phys. Rev. 109), 1 (1958). but are in quantitative agreement with the thermal diffusivity \\chiL = 0.49 ( n barv b^2 ) λ_D^2 ∝ n^0 B^0 T-1/2 recently predicted to result from long-range ``guiding center'' collisions.(D.H.E. Dubin et al., Phys. Rev. Lett. 78), 3868 (1997). In these long-range collisions, which occur in plasmas with λD > r_c, particles on well-separated field lines exchange parallel kinetic energy only. In the present experiments, the maximal impact parameters are ρ <= λ_D but in larger plasmas (with cross-field dimension L > 100 λ_D) the emission and absorption of plasma waves over impact parameters ρ <= L is predicted to give a further enhancement of the heat transport. The experiments are performed by heating (or cooling) the ions locally with a laser beam to create a thermal gradient. A second laser is then used to monitor the resulting radial heat flow. Remarkably, the ions are held in steady-state for periods of weeks by an applied ``rotating wall'' drive;(X.-P. Huang et al., Phys. Rev. Lett. 78), 875 (1997). this allows for accurate, repeatable heat transport measurements over a wide range of plasma parameters. To date, the thermal diffusivity has been measured over a range of 100 in density, 4 in magnetic field, and 10^4 in temperature; and it is found that long-range collisions dominate the heat transport over this entire range.(E.M. Hollmann et al., Phys. Rev. Lett. 82). 4930 (1999). Separate measurements of the perp-to-parallel thermal isotropization rates show that short-range velocity

  6. On the origin of long-range correlations in texts.

    PubMed

    Altmann, Eduardo G; Cristadoro, Giampaolo; Esposti, Mirko Degli

    2012-07-17

    The complexity of human interactions with social and natural phenomena is mirrored in the way we describe our experiences through natural language. In order to retain and convey such a high dimensional information, the statistical properties of our linguistic output has to be highly correlated in time. An example are the robust observations, still largely not understood, of correlations on arbitrary long scales in literary texts. In this paper we explain how long-range correlations flow from highly structured linguistic levels down to the building blocks of a text (words, letters, etc..). By combining calculations and data analysis we show that correlations take form of a bursty sequence of events once we approach the semantically relevant topics of the text. The mechanisms we identify are fairly general and can be equally applied to other hierarchical settings.

  7. Stable swarming using adaptive long-range interactions.

    PubMed

    Gorbonos, Dan; Gov, Nir S

    2017-04-01

    Sensory mechanisms in biology, from cells to humans, have the property of adaptivity, whereby the response produced by the sensor is adapted to the overall amplitude of the signal, reducing the sensitivity in the presence of strong stimulus, while increasing it when it is weak. This property is inherently energy consuming and a manifestation of the nonequilibrium nature of living organisms. We explore here how adaptivity affects the effective forces that organisms feel due to others in the context of a uniform swarm, in both two and three dimensions. The interactions between the individuals are taken to be attractive and long-range and of power-law form. We find that the effects of adaptivity inside the swarm are dramatic, where the effective forces decrease (or remain constant) with increasing swarm density. Linear stability analysis demonstrates how this property prevents collapse (Jeans instability), when the forces are adaptive. Adaptivity therefore endows swarms with a natural mechanism for self-stabilization.

  8. Theory of Long-Range Ultracold Atom-Molecule Photoassociation.

    PubMed

    Pérez-Ríos, Jesús; Lepers, Maxence; Dulieu, Olivier

    2015-08-14

    The creation of ultracold molecules is currently limited to diatomic species. In this Letter, we present a theoretical description of the photoassociation of ultracold atoms and molecules to create ultracold excited triatomic molecules, thus being a novel example of a light-assisted ultracold chemical reaction. The calculation of the photoassociation rate of an ultracold Cs_{2} molecule in its rovibrational ground state with an ultracold Cs atom at frequencies close to its resonant excitation is reported, based on the solution of the quantum dynamics involving the atom-molecule long-range interactions and assuming a model potential for the short-range physics. The rate for the formation of excited Cs_{3} molecules is predicted to be comparable with currently observed atom-atom photoassociation rates. We formulate an experimental proposal to observe this process relying on the available techniques of optical lattices and standard photoassociation spectroscopy.

  9. Stripe Glass from Competing Short and Long Range Interactions

    NASA Astrophysics Data System (ADS)

    Zimanyi, Gergely; Pike, Chris; Scalettar, Richard

    2006-03-01

    We investigate a film of dipoles oriented perpendicular to the film. The system's behavior is related to inhomogeneous non-Fermi liquid states, recently studied by Kivelson and Spivak and by Schmalian and Wolynes. The competition of short range ferromagnetic and long range antiferromagnetic interactions causes the formation of stripes. The system has an ordered stripe-crystal phase. However, this phase is avoided unless an extremely slow annealing protocol is utilized. Without any quenched disorder during normal annealing protocols the frustrated competing interactions self-generate a stripe-glass state. The stripe glass exhibits aging, manifesting itself in waiting-time dependent correlations. A scaling analysis of the aging is presented. The long time behavior shows stretched exponential behavior, the relaxation time surprisingly exhibiting a simple activated form. Dynamical inhomogeneities are identified, both frozen domains and instantaneous crystallites.

  10. Long-range correlations in quantum systems with aperiodic Hamiltonians

    NASA Astrophysics Data System (ADS)

    Lin, Zhifang; Goda, Masaki

    1997-03-01

    An efficient algorithm for the computation of correlation function (CF) at very long distances is presented for quantum systems whose Hamiltonian is formed by the substitution aperiodic sequence alternating over unit intervals in time or space. The algorithm reorganizes the expression of the CF in such a way that the evaluation of the CF at distances equal to some special numbers is related to a family of graphs generated recursively. As examples of applications, we evaluate the CF, over unprecedentedly long time intervals up to order of 1012, for aperiodic two-level systems subject to kicking perturbations that are in the Thue-Morse, the period-doubling, and the Rudin-Shapiro sequences, respectively. Our results show the presence of long-range correlations in all these aperiodic quantum systems.

  11. Long-range energy transport in photosystem II.

    PubMed

    Roden, Jan J J; Bennett, Doran I G; Whaley, K Birgitta

    2016-06-28

    We simulate the long-range inter-complex electronic energy transfer in photosystem II-from the antenna complex, via a core complex, to the reaction center-using a non-Markovian (ZOFE) quantum master equation description that allows the electronic coherence involved in the energy transfer to be explicitly included at all length scales. This allows us to identify all locations where coherence is manifested and to further identify the pathways of the energy transfer in the full network of coupled chromophores using a description based on excitation probability currents. We investigate how the energy transfer depends on the initial excitation-localized, coherent initial excitation versus delocalized, incoherent initial excitation-and find that the overall energy transfer is remarkably robust with respect to such strong variations of the initial condition. To explore the importance of vibrationally enhanced transfer and to address the question of optimization in the system parameters, we systematically vary the strength of the coupling between the electronic and the vibrational degrees of freedom. We find that the natural parameters lie in a (broad) region that enables optimal transfer efficiency and that the overall long-range energy transfer on a ns time scale appears to be very robust with respect to variations in the vibronic coupling of up to an order of magnitude. Nevertheless, vibrationally enhanced transfer appears to be crucial to obtain a high transfer efficiency, with the latter falling sharply for couplings outside the optimal range. Comparison of our full quantum simulations to results obtained with a "classical" rate equation based on a modified-Redfield/generalized-Förster description previously used to simulate energy transfer dynamics in the entire photosystem II complex shows good agreement for the overall time scales of excitation energy transport.

  12. Long-Range Correlations of Global Sea Surface Temperature.

    PubMed

    Jiang, Lei; Zhao, Xia; Wang, Lu

    2016-01-01

    Scaling behaviors of the global monthly sea surface temperature (SST) derived from 1870-2009 average monthly data sets of Hadley Centre Sea Ice and SST (HadISST) are investigated employing detrended fluctuation analysis (DFA). The global SST fluctuations are found to be strong positively long-range correlated at all pertinent time-intervals. The value of scaling exponent is larger in the tropics than those in the intermediate latitudes of the northern and southern hemispheres. DFA leads to the scaling exponent α = 0.87 over the globe (60°S~60°N), northern hemisphere (0°N~60°N), and southern hemisphere (0°S~60°S), α = 0.84 over the intermediate latitude of southern hemisphere (30°S~60°S), α = 0.81 over the intermediate latitude of northern hemisphere (30°N~60°N) and α = 0.90 over the tropics 30°S~30°N [fluctuation F(s) ~ sα], which the fluctuations of monthly SST anomaly display long-term correlated behaviors. Furthermore, the larger the standard deviation is, the smaller long-range correlations (LRCs) of SST in the corresponding regions, especially in three distinct upwelling areas. After the standard deviation is taken into account, an index χ = α * σ is introduced to obtain the spatial distributions of χ. There exists an obvious change of global SST in central east and northern Pacific and the northwest Atlantic. This may be as a clue on predictability of climate and ocean variabilities.

  13. Two-Dimensional SIR Epidemics with Long Range Infection

    NASA Astrophysics Data System (ADS)

    Grassberger, Peter

    2013-10-01

    We extend a recent study of susceptible-infected-removed epidemic processes with long range infection (referred to as I in the following) from 1-dimensional lattices to lattices in two dimensions. As in I we use hashing to simulate very large lattices for which finite size effects can be neglected, in spite of the assumed power law p( x)˜| x|- σ-2 for the probability that a site can infect another site a distance vector x apart. As in I we present detailed results for the critical case, for the supercritical case with σ=2, and for the supercritical case with 0< σ<2. For the latter we verify the stretched exponential growth of the infected cluster with time predicted by M. Biskup. For σ=2 we find generic power laws with σ-dependent exponents in the supercritical phase, but no Kosterlitz-Thouless (KT) like critical point as in 1-d. Instead of diverging exponentially with the distance from the critical point, the correlation length increases with an inverse power, as in an ordinary critical point. Finally we study the dependence of the critical exponents on σ in the regime 0< σ<2, and compare with field theoretic predictions. In particular we discuss in detail whether the critical behavior for σ slightly less than 2 is in the short range universality class, as conjectured recently by F. Linder et al. As in I we also consider a modified version of the model where only some of the contacts are long range, the others being between nearest neighbors. If the number of the latter reaches the percolation threshold, the critical behavior is changed but the supercritical behavior stays qualitatively the same.

  14. Incoherent shock waves in long-range optical turbulence

    NASA Astrophysics Data System (ADS)

    Xu, G.; Garnier, J.; Faccio, D.; Trillo, S.; Picozzi, A.

    2016-10-01

    Considering the nonlinear Schrödinger (NLS) equation as a representative model, we report a unified presentation of different forms of incoherent shock waves that emerge in the long-range interaction regime of a turbulent optical wave system. These incoherent singularities can develop either in the temporal domain through a highly noninstantaneous nonlinear response, or in the spatial domain through a highly nonlocal nonlinearity. In the temporal domain, genuine dispersive shock waves (DSW) develop in the spectral dynamics of the random waves, despite the fact that the causality condition inherent to the response function breaks the Hamiltonian structure of the NLS equation. Such spectral incoherent DSWs are described in detail by a family of singular integro-differential kinetic equations, e.g. Benjamin-Ono equation, which are derived from a nonequilibrium kinetic formulation based on the weak Langmuir turbulence equation. In the spatial domain, the system is shown to exhibit a large scale global collective behavior, so that it is the fluctuating field as a whole that develops a singularity, which is inherently an incoherent object made of random waves. Despite the Hamiltonian structure of the NLS equation, the regularization of such a collective incoherent shock does not require the formation of a DSW - the regularization is shown to occur by means of a different process of coherence degradation at the shock point. We show that the collective incoherent shock is responsible for an original mechanism of spontaneous nucleation of a phase-space hole in the spectrogram dynamics. The robustness of such a phase-space hole is interpreted in the light of incoherent dark soliton states, whose different exact solutions are derived in the framework of the long-range Vlasov formalism.

  15. Long-range energy transport in photosystem II

    NASA Astrophysics Data System (ADS)

    Roden, Jan J. J.; Bennett, Doran I. G.; Whaley, K. Birgitta

    2016-06-01

    We simulate the long-range inter-complex electronic energy transfer in photosystem II - from the antenna complex, via a core complex, to the reaction center - using a non-Markovian (ZOFE) quantum master equation description that allows the electronic coherence involved in the energy transfer to be explicitly included at all length scales. This allows us to identify all locations where coherence is manifested and to further identify the pathways of the energy transfer in the full network of coupled chromophores using a description based on excitation probability currents. We investigate how the energy transfer depends on the initial excitation - localized, coherent initial excitation versus delocalized, incoherent initial excitation - and find that the overall energy transfer is remarkably robust with respect to such strong variations of the initial condition. To explore the importance of vibrationally enhanced transfer and to address the question of optimization in the system parameters, we systematically vary the strength of the coupling between the electronic and the vibrational degrees of freedom. We find that the natural parameters lie in a (broad) region that enables optimal transfer efficiency and that the overall long-range energy transfer on a ns time scale appears to be very robust with respect to variations in the vibronic coupling of up to an order of magnitude. Nevertheless, vibrationally enhanced transfer appears to be crucial to obtain a high transfer efficiency, with the latter falling sharply for couplings outside the optimal range. Comparison of our full quantum simulations to results obtained with a "classical" rate equation based on a modified-Redfield/generalized-Förster description previously used to simulate energy transfer dynamics in the entire photosystem II complex shows good agreement for the overall time scales of excitation energy transport.

  16. Long-Range Correlations of Global Sea Surface Temperature

    PubMed Central

    Jiang, Lei; Zhao, Xia; Wang, Lu

    2016-01-01

    Scaling behaviors of the global monthly sea surface temperature (SST) derived from 1870–2009 average monthly data sets of Hadley Centre Sea Ice and SST (HadISST) are investigated employing detrended fluctuation analysis (DFA). The global SST fluctuations are found to be strong positively long-range correlated at all pertinent time-intervals. The value of scaling exponent is larger in the tropics than those in the intermediate latitudes of the northern and southern hemispheres. DFA leads to the scaling exponent α = 0.87 over the globe (60°S~60°N), northern hemisphere (0°N~60°N), and southern hemisphere (0°S~60°S), α = 0.84 over the intermediate latitude of southern hemisphere (30°S~60°S), α = 0.81 over the intermediate latitude of northern hemisphere (30°N~60°N) and α = 0.90 over the tropics 30°S~30°N [fluctuation F(s) ~ sα], which the fluctuations of monthly SST anomaly display long-term correlated behaviors. Furthermore, the larger the standard deviation is, the smaller long-range correlations (LRCs) of SST in the corresponding regions, especially in three distinct upwelling areas. After the standard deviation is taken into account, an index χ = α * σ is introduced to obtain the spatial distributions of χ. There exists an obvious change of global SST in central east and northern Pacific and the northwest Atlantic. This may be as a clue on predictability of climate and ocean variabilities. PMID:27100397

  17. Efficient Exciton Harvesting through Long-Range Energy Transfer.

    PubMed

    Wang, Yanbin; Ohkita, Hideo; Benten, Hiroaki; Ito, Shinzaburo

    2015-04-27

    Efficient exciton collection at charge-generation sites is one of the key requirements for the improvement in power conversion efficiency (PCE) of organic solar cells, because only excitons arriving at a donor/acceptor interface can be dissociated into free charge carriers. We evaluated the effective diffusion length in poly(3-hexylthiophene) (P3HT) by using donor/acceptor bilayers with two different exciton-quenching acceptors. One is an insoluble fullerene polymer (p-PCBVB), which is an efficient electron-accepting material with negligible absorption in the visible region. The other is a low-bandgap polymer, poly[(4,4-bis(2-ethylhexyl)-dithieno[3,2-b:2',3'-d]silole)-2,6-diyl-alt-(2,1,3-benzothiadiazole)-4,7-diyl], (PSBTBT). This polymer has a large absorption band in the near-IR region, which overlaps well with the emission band of P3HT. The effective diffusion length of P3HT excitons is evaluated to be 15 nm for P3HT/p-PCBVB bilayers and improved to 30 nm for P3HT/PSBTBT bilayers. This improvement is ascribed to long-range energy transfer from P3HT to PSBTBT. This finding suggests that the effective diffusion length of P3HT excitons can be increased through long-range energy transfer by incorporating PSBTBT into P3HT/PCBM blends. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. An Architectural Model of Visual Motion Understanding

    DTIC Science & Technology

    1989-08-01

    responsible for at least some long-range apparent motion phenomena (Watson and Ahumada , 19851. The logical conclusion to this line of argument would be to...x direction. This idea is the basis of the work by Heeger mentioned in the previous section. Watson and Ahumada [1985] propose computing the sum of...oscillates at a frequency related to local velocity. Watson and Ahumada provide a detailed description of how the filters are constructed and how

  19. In-flight sleep, pilot fatigue and Psychomotor Vigilance Task performance on ultra-long range versus long range flights.

    PubMed

    Gander, Philippa H; Signal, T Leigh; van den Berg, Margo J; Mulrine, Hannah M; Jay, Sarah M; Jim Mangie, Captain

    2013-12-01

    This study evaluated whether pilot fatigue was greater on ultra-long range (ULR) trips (flights >16 h on 10% of trips in a 90-day period) than on long range (LR) trips. The within-subjects design controlled for crew complement, pattern of in-flight breaks, flight direction and departure time. Thirty male Captains (mean age = 54.5 years) and 40 male First officers (mean age = 48.0 years) were monitored on commercial passenger flights (Boeing 777 aircraft). Sleep was monitored (actigraphy, duty/sleep diaries) from 3 days before the first study trip to 3 days after the second study trip. Karolinska Sleepiness Scale, Samn-Perelli fatigue ratings and a 5-min Psychomotor Vigilance Task were completed before, during and after every flight. Total sleep in the 24 h before outbound flights and before inbound flights after 2-day layovers was comparable for ULR and LR flights. All pilots slept on all flights. For each additional hour of flight time, they obtained an estimated additional 12.3 min of sleep. Estimated mean total sleep was longer on ULR flights (3 h 53 min) than LR flights (3 h 15 min; P(F) = 0.0004). Sleepiness ratings were lower and mean reaction speed was faster at the end of ULR flights. Findings suggest that additional in-flight sleep mitigated fatigue effectively on longer flights. Further research is needed to clarify the contributions to fatigue of in-flight sleep versus time awake at top of descent. The study design was limited to eastward outbound flights with two Captains and two First Officers. Caution must be exercised when extrapolating to different operations. © 2013 European Sleep Research Society.

  20. Classical investigation of long-range coherence in biological systems

    NASA Astrophysics Data System (ADS)

    Preto, Jordane

    2016-12-01

    Almost five decades ago, H. Fröhlich [H. Fröhlich, "Long-range coherence and energy storage in biological systems," Int. J. Quantum Chem. 2(5), 641-649 (1968)] reported, on a theoretical basis, that the excitation of quantum modes of vibration in contact with a thermal reservoir may lead to steady states, where under high enough rate of energy supply, only specific low-frequency modes of vibration are strongly excited. This nonlinear phenomenon was predicted to occur in biomolecular systems, which are known to exhibit complex vibrational spectral properties, especially in the terahertz frequency domain. However, since the effects of terahertz or lower-frequency modes are mainly classical at physiological temperatures, there are serious doubts that Fröhlich's quantum description can be applied to predict such a coherent behavior in a biological environment, as suggested by the author. In addition, a quantum formalism makes the phenomenon hard to investigate using realistic molecular dynamics simulations (MD) as they are usually based on the classical principles. In the current paper, we provide a general classical Hamiltonian description of a nonlinear open system composed of many degrees of freedom (biomolecular structure) excited by an external energy source. It is shown that a coherent behaviour similar to Fröhlich's effect is to be expected in the classical case for a given range of parameter values. Thus, the supplied energy is not completely thermalized but stored in a highly ordered fashion. The connection between our Hamiltonian description, carried out in the space of normal modes, and a more standard treatment in the physical space is emphasized in order to facilitate the prediction of the effect from MD simulations. It is shown how such a coherent phenomenon may induce long-range resonance effects that could be of critical importance at the biomolecular level. The present work is motivated by recent experimental evidences of long-lived excited low

  1. Classical investigation of long-range coherence in biological systems.

    PubMed

    Preto, Jordane

    2016-12-01

    Almost five decades ago, H. Fröhlich [H. Fröhlich, "Long-range coherence and energy storage in biological systems," Int. J. Quantum Chem. 2(5), 641-649 (1968)] reported, on a theoretical basis, that the excitation of quantum modes of vibration in contact with a thermal reservoir may lead to steady states, where under high enough rate of energy supply, only specific low-frequency modes of vibration are strongly excited. This nonlinear phenomenon was predicted to occur in biomolecular systems, which are known to exhibit complex vibrational spectral properties, especially in the terahertz frequency domain. However, since the effects of terahertz or lower-frequency modes are mainly classical at physiological temperatures, there are serious doubts that Fröhlich's quantum description can be applied to predict such a coherent behavior in a biological environment, as suggested by the author. In addition, a quantum formalism makes the phenomenon hard to investigate using realistic molecular dynamics simulations (MD) as they are usually based on the classical principles. In the current paper, we provide a general classical Hamiltonian description of a nonlinear open system composed of many degrees of freedom (biomolecular structure) excited by an external energy source. It is shown that a coherent behaviour similar to Fröhlich's effect is to be expected in the classical case for a given range of parameter values. Thus, the supplied energy is not completely thermalized but stored in a highly ordered fashion. The connection between our Hamiltonian description, carried out in the space of normal modes, and a more standard treatment in the physical space is emphasized in order to facilitate the prediction of the effect from MD simulations. It is shown how such a coherent phenomenon may induce long-range resonance effects that could be of critical importance at the biomolecular level. The present work is motivated by recent experimental evidences of long-lived excited low

  2. Long-range global population projections, as assessed in 1980.

    PubMed

    1982-01-01

    UN medium range projections prepared in the 1980 assessment projected the population of individual countries up to the year 2025. The long range projections discussed here were prepared by projecting the population of 8 major world regions from 2025-2100. The purpose of the projection was to observe the implications of the changes from the 1978 assessment made in the 1980 medium range projections on the long range projections of the world's populations. As in previous projections, high, medium, and low variants were prepared in which fertility is assumed to be constant at the replacement level but at different times in the future. In addition, these projections contain 2 variants not previously prepared--namely, the growth and decline variants, in which the ultimate net reproduction rate is 1.05 and 0.95, respectively. In all the variants, expectation of life at birth is assumed to reach 75 years for males and 80 for females. According to the current medium variant projection, the earth's population will become stationary after 2095 at 10.2 billion persons, compared with a total of 10.5 billion projected in the 1978 assessment. The lower projection is largely attributable to a recent decline in the growth rate of several countries in South Asia which was greater than previously assumed. When the world population becomes stationary, both crude birth and death rates would be about 13/1000. In the decline variant, total population would peak at 7.7 billion in 2055, then decline gradually to 7.2 billion in 2100. The total population as projected by the growth variant would equal 14.9 billion in 2100 and would still be growing slowly. Between 1980 and 2050, 95% of the world's growth will occur in the currently less developed regions. Their share of total population will increase from 75-85% during that period. The age structure in all regions is expected to converge to 1 in which the median age is 39 years, the proportion both below age 15 and above age 64 is about 19

  3. Long-range magnetic coupling across a polar insulating layer.

    PubMed

    Lü, W M; Saha, Surajit; Wang, X Renshaw; Liu, Z Q; Gopinadhan, K; Annadi, A; Zeng, S W; Huang, Z; Bao, B C; Cong, C X; Venkatesan, M; Yu, T; Coey, J M D; Ariando; Venkatesan, T

    2016-03-16

    Magnetic interactions in solids are normally mediated by short-range exchange or weak dipole fields. Here we report a magnetic interaction that can propagate over long distances (∼10 nm) across a polar insulating oxide spacer. Evidence includes oscillations of magnetization, coercivity and field-cooled loop shift with the thickness of LaAlO3 in La0.67Sr0.33MnO3/LaAlO3/SrTiO3 heterostructures. Similar modifications of the hysteresis loop appear when two coupled films of La0.67Sr0.33MnO3 are separated by LaAlO3, or another polar insulator, but they are absent when the oxide spacer layer is nonpolar. The loop shift is attributed to strong spin-orbit coupling and Dzyaloshinskii-Moriya interaction at the interfaces. There is evidence from inelastic light scattering that the polar spacer mediates long-range transmission of orbital magnetization. This coupling mechanism is expected to apply for any conducting ferromagnetic oxide with mixed valence; in view of electron hopping frequency involved, it raises the prospect of terahertz tunability of magnetic coupling.

  4. Ultracold Long-Range Rydberg Molecules with Complex Multichannel Spectra

    NASA Astrophysics Data System (ADS)

    Eiles, Matthew; Greene, Chris

    2016-05-01

    A generalized class of exotic long-range Rydberg molecules consisting of a multichannel Rydberg atom bound to a distant ground state atom by the Rydberg electron is predicted. These molecules are characterized by the rich physics provided by the strongly perturbed multichannel Rydberg spectra of divalent atoms, in contrast to the regular Rydberg series of the alkali atoms used to form Rydberg molecules to date. These multichannel Rydberg molecules exhibit favorable properties for laser excitation, because states exist where the quantum defect varies strongly with the principal quantum number n. In particular, the nd Rydberg state of calcium becomes nearly degenerate with states of high orbital angular momentum over the range 17 < n < 22 , promoting its admixture into the high l deeply bound ``trilobite'' molecule states and thereby circumventing the usual difficulty posed by electric dipole selection rules. Further novel molecular states are predicted to occur in the low- J states of silicon, which are strongly perturbed due to channel interactions between Rydberg series leading to the spin-orbit split ionization thresholds. These interactions manifest themselves in potential curves exhibiting two distinct length scales, providing novel opportunities for quantum manipulation. Supported in part by the National Science Foundation under Grant No. PHY-1306905.

  5. Long-range interacting systems in the unconstrained ensemble.

    PubMed

    Latella, Ivan; Pérez-Madrid, Agustín; Campa, Alessandro; Casetti, Lapo; Ruffo, Stefano

    2017-01-01

    Completely open systems can exchange heat, work, and matter with the environment. While energy, volume, and number of particles fluctuate under completely open conditions, the equilibrium states of the system, if they exist, can be specified using the temperature, pressure, and chemical potential as control parameters. The unconstrained ensemble is the statistical ensemble describing completely open systems and the replica energy is the appropriate free energy for these control parameters from which the thermodynamics must be derived. It turns out that macroscopic systems with short-range interactions cannot attain equilibrium configurations in the unconstrained ensemble, since temperature, pressure, and chemical potential cannot be taken as a set of independent variables in this case. In contrast, we show that systems with long-range interactions can reach states of thermodynamic equilibrium in the unconstrained ensemble. To illustrate this fact, we consider a modification of the Thirring model and compare the unconstrained ensemble with the canonical and grand-canonical ones: The more the ensemble is constrained by fixing the volume or number of particles, the larger the space of parameters defining the equilibrium configurations.

  6. Long-range RNA pairings contribute to mutually exclusive splicing

    PubMed Central

    Yue, Yuan; Yang, Yun; Dai, Lanzhi; Cao, Guozheng; Chen, Ran; Hong, Weiling; Liu, Baoping; Shi, Yang; Meng, Yijun; Shi, Feng; Xiao, Mu; Jin, Yongfeng

    2016-01-01

    Mutually exclusive splicing is an important means of increasing the protein repertoire, by which the Down's syndrome cell adhesion molecule (Dscam) gene potentially generates 38,016 different isoforms in Drosophila melanogaster. However, the regulatory mechanisms remain obscure due to the complexity of the Dscam exon cluster. Here, we reveal a molecular model for the regulation of the mutually exclusive splicing of the serpent pre-mRNA based on competition between upstream and downstream RNA pairings. Such dual RNA pairings confer fine tuning of the inclusion of alternative exons. Moreover, we demonstrate that the splicing outcome of alternative exons is mediated in relative pairing strength-correlated mode. Combined comparative genomics analysis and experimental evidence revealed similar bidirectional structural architectures in exon clusters 4 and 9 of the Dscam gene. Our findings provide a novel mechanistic framework for the regulation of mutually exclusive splicing and may offer potentially applicable insights into long-range RNA–RNA interactions in gene regulatory networks. PMID:26554032

  7. Long-range interaction between heterogeneously charged membranes.

    PubMed

    Jho, Y S; Brewster, R; Safran, S A; Pincus, P A

    2011-04-19

    Despite their neutrality, surfaces or membranes with equal amounts of positive and negative charge can exhibit long-range electrostatic interactions if the surface charge is heterogeneous; this can happen when the surface charges form finite-size domain structures. These domains can be formed in lipid membranes where the balance of the different ranges of strong but short-ranged hydrophobic interactions and longer-ranged electrostatic repulsion result in a finite, stable domain size. If the domain size is large enough, oppositely charged domains in two opposing surfaces or membranes can be strongly correlated by the electrostatic interactions; these correlations give rise to an attractive interaction of the two membranes or surfaces over separations on the order of the domain size. We use numerical simulations to demonstrate the existence of strong attractions at separations of tens of nanometers. Large line tensions result in larger domains but also increase the charge density within the domain. This promotes correlations and, as a result, increases the intermembrane attraction. On the other hand, increasing the salt concentration increases both the domain size and degree of domain anticorrelation, but the interactions are ultimately reduced due to increased screening. The result is a decrease in the net attraction as salt concentration is increased. © 2011 American Chemical Society

  8. Long Range Chiral Imprinting of Cu(110) by Tartaric Acid

    SciTech Connect

    Lawton, T J; Pushkarev, V; Wei, D; Lucci, F R; Sholl, D S; Gellman, A J; Sykes, E C. H.

    2013-10-31

    Restructuring of metals by chiral molecules represents an important route to inducing and controlling enantioselective surface chemistry. Tartaric acid adsorption on Cu(110) has served as a useful system for understanding many aspects of chiral molecule adsorption and ordering on a metal surface, and a number of chiral and achiral unit cells have been reported. Herein, we show that given the appropriate annealing treatment, singly deprotonated tartaric acid monolayers can restructure the Cu metal itself, and that the resulting structure is both highly ordered and chiral. Molecular resolution scanning tunneling microscopy reveals that singly deprotonated tartaric acid extracts Cu atoms from the Cu(110) surface layer and incorporates them into highly ordered, chiral adatom arrays capped by a continuous molecular layer. Further evidence for surface restructuring comes from images of atom-deep trenches formed in the Cu(110) surface during the process. These trenches also run in low symmetry directions and are themselves chiral. Simulated scanning tunneling microscopy images are consistent with the appearance of the added atom rows and etched trenches. The chiral imprinting results in a long-range, highly ordered unit cell covering the whole surface as confirmed by low energy electron diffraction. Details of the restructuring mechanism were further investigated via time-lapse imaging at elevated temperature. This work reveals the stages of nanoscale surface restructuring and offers an interesting method for chiral modification of an achiral metal surface.

  9. Long-range RNA pairings contribute to mutually exclusive splicing.

    PubMed

    Yue, Yuan; Yang, Yun; Dai, Lanzhi; Cao, Guozheng; Chen, Ran; Hong, Weiling; Liu, Baoping; Shi, Yang; Meng, Yijun; Shi, Feng; Xiao, Mu; Jin, Yongfeng

    2016-01-01

    Mutually exclusive splicing is an important means of increasing the protein repertoire, by which the Down's syndrome cell adhesion molecule (Dscam) gene potentially generates 38,016 different isoforms in Drosophila melanogaster. However, the regulatory mechanisms remain obscure due to the complexity of the Dscam exon cluster. Here, we reveal a molecular model for the regulation of the mutually exclusive splicing of the serpent pre-mRNA based on competition between upstream and downstream RNA pairings. Such dual RNA pairings confer fine tuning of the inclusion of alternative exons. Moreover, we demonstrate that the splicing outcome of alternative exons is mediated in relative pairing strength-correlated mode. Combined comparative genomics analysis and experimental evidence revealed similar bidirectional structural architectures in exon clusters 4 and 9 of the Dscam gene. Our findings provide a novel mechanistic framework for the regulation of mutually exclusive splicing and may offer potentially applicable insights into long-range RNA-RNA interactions in gene regulatory networks. © 2015 Yue et al.; Published by Cold Spring Harbor Laboratory Press for the RNA Society.

  10. Long-Range Architecture in a Viral RNA Genome

    PubMed Central

    Archer, Eva J.; Simpson, Mark A.; Watts, Nicholas J.; O’Kane, Rory; Wang, Bangchen; Erie, Dorothy A.; McPherson, Alex; Weeks, Kevin M.

    2013-01-01

    We have developed a model for the secondary structure of the 1058-nucleotide plus-strand RNA genome of the icosahedral satellite tobacco mosaic virus (STMV) using nucleotide-resolution SHAPE chemical probing of the viral RNA isolated from virions and within the virion, perturbation of interactions distant in the primary sequence, and atomic force microscopy. These data are consistent with long-range base pairing interactions and a three-domain genome architecture. The compact domains of the STMV RNA have dimensions of 10 to 45 nm. Each of the three domains corresponds to a specific functional component of the virus: The central domain corresponds to the coding sequence of the single (capsid) protein encoded by the virus, whereas the 5′ and 3′ untranslated domains span signals essential for translation and replication, respectively. This three-domain architecture is compatible with interactions between the capsid protein and short RNA helices previously visualized by crystallography. STMV is among the simplest of the icosahedral viruses but, nonetheless, has an RNA genome with a complex higher-order structure that likely reflects high information content and an evolutionary relationship between RNA domain structure and essential replicative functions. PMID:23614526

  11. Record length requirement of long-range dependent teletraffic

    NASA Astrophysics Data System (ADS)

    Li, Ming

    2017-04-01

    This article contributes the highlights mainly in two folds. On the one hand, it presents a formula to compute the upper bound of the variance of the correlation periodogram measurement of teletraffic (traffic for short) with long-range dependence (LRD) for a given record length T and a given value of the Hurst parameter H (Theorems 1 and 2). On the other hand, it proposes two formulas for the computation of the variance upper bound of the correlation periodogram measurement of traffic of fractional Gaussian noise (fGn) type and the generalized Cauchy (GC) type, respectively (Corollaries 1 and 2). They may constitute a reference guideline of record length requirement of traffic with LRD. In addition, record length requirement for the correlation periodogram measurement of traffic with either the Schuster type or the Bartlett one is studied and the present results about it show that both types of periodograms may be used for the correlation measurement of traffic with a pre-desired variance bound of correlation estimation. Moreover, real traffic in the Internet Archive by the Special Interest Group on Data Communication under the Association for Computing Machinery of US (ACM SIGCOMM) is analyzed in the case study in this topic.

  12. Assessing long-range transport potential of persistent organic pollutants

    SciTech Connect

    Beyer, A.; Mackay, D.; Matthies, M.; Wania, F.; Webster, E.

    2000-02-15

    An analysis is presented of the factors controlling the potential for the long-range transport (LRT) of persistent organic pollutants subject to degrading reactions and reversible transport to other environmental media. The approach adopted generalizes those developed previously by van Pul et al. and Bennett et al. to estimate a characteristic travel distance (CTD) or a half-distance (analogous to a half-life) for a substance present in a mobile medium such as air and subject to reversible transport to other media such as soil and water. For substances discharged to immobile media, such as pesticides to soil, an effective travel distance (ETD) is defined as the distance that, for example, 1% of the discharged chemical may be transported. It is shown that existing multimedia box models can be used to estimate CTD and that a simple relationship exists between CTD and overall environmental persistence, which can be displayed graphically. CTDs in air and water are calculated illustratively for 18 chemicals, and recommendations are made regarding ranking or grouping chemicals according to their potential for LRT.

  13. Confirmation of NLDN Long Range Strike Locations with LIS Observations

    NASA Technical Reports Server (NTRS)

    Boeck, William; Boccippio, Dennis; Goodman, Steve; Cummins, Kenneth; Cramer, John; Goodman, H. Michael (Technical Monitor)

    2000-01-01

    This study compares the lightning locations reported by the National Lightning Detection Network (NLDN) with the lightning locations determined by the Lightning Imaging Sensor (LIS). The NLDN system identifies the rf signature of cloud-to-ground lightning. The LIS data is the top level of a hierarchy of optical data objects. The centroid and timing of each LIS lightning activity center are compared with each flash in a subset of the NLDN long range lightning location data in a portion of the Atlantic Ocean and the Caribbean Sea consisting of those locations more than 625 km from any sensor. This subset is produced by analyzing each reported NLDN location to determine if that location is within the LIS field of view at the time of the reported flash. The Tropical Rainfall Measuring Mission Satellite (TRMM) orbit limits the cross-sensor comparison to tropical and sub-tropical regions. Because the rf-detection system depends on ionospheric propagation conditions, a separate analysis was made for daylight conditions at both source and sensor as well as nighttime at both places. A full year of data is compared to provide an adequate sample of each data set. Confirmation of lightning in the general location of the NLDN report is established when LIS detected one or more centers of lightning activity within a 2 degree radius from the NLDN location.

  14. Stochastic Kinetic Monte Carlo algorithms for long-range Hamiltonians

    SciTech Connect

    Mason, D R; Rudd, R E; Sutton, A P

    2003-10-13

    We present a higher order kinetic Monte Carlo methodology suitable to model the evolution of systems in which the transition rates are non- trivial to calculate or in which Monte Carlo moves are likely to be non- productive flicker events. The second order residence time algorithm first introduced by Athenes et al.[1] is rederived from the n-fold way algorithm of Bortz et al.[2] as a fully stochastic algorithm. The second order algorithm can be dynamically called when necessary to eliminate unproductive flickering between a metastable state and its neighbors. An algorithm combining elements of the first order and second order methods is shown to be more efficient, in terms of the number of rate calculations, than the first order or second order methods alone while remaining statistically identical. This efficiency is of prime importance when dealing with computationally expensive rate functions such as those arising from long- range Hamiltonians. Our algorithm has been developed for use when considering simulations of vacancy diffusion under the influence of elastic stress fields. We demonstrate the improved efficiency of the method over that of the n-fold way in simulations of vacancy diffusion in alloys. Our algorithm is seen to be an order of magnitude more efficient than the n-fold way in these simulations. We show that when magnesium is added to an Al-2at.%Cu alloy, this has the effect of trapping vacancies. When trapping occurs, we see that our algorithm performs thousands of events for each rate calculation performed.

  15. Long-range magnetic coupling across a polar insulating layer

    PubMed Central

    Lü, W. M.; Saha, Surajit; Wang, X. Renshaw; Liu, Z. Q.; Gopinadhan, K.; Annadi, A.; Zeng, S. W.; Huang, Z.; Bao, B. C.; Cong, C. X.; Venkatesan, M.; Yu, T.; Coey, J. M. D.; Ariando; Venkatesan, T.

    2016-01-01

    Magnetic interactions in solids are normally mediated by short-range exchange or weak dipole fields. Here we report a magnetic interaction that can propagate over long distances (∼10 nm) across a polar insulating oxide spacer. Evidence includes oscillations of magnetization, coercivity and field-cooled loop shift with the thickness of LaAlO3 in La0.67Sr0.33MnO3/LaAlO3/SrTiO3 heterostructures. Similar modifications of the hysteresis loop appear when two coupled films of La0.67Sr0.33MnO3 are separated by LaAlO3, or another polar insulator, but they are absent when the oxide spacer layer is nonpolar. The loop shift is attributed to strong spin–orbit coupling and Dzyaloshinskii–Moriya interaction at the interfaces. There is evidence from inelastic light scattering that the polar spacer mediates long-range transmission of orbital magnetization. This coupling mechanism is expected to apply for any conducting ferromagnetic oxide with mixed valence; in view of electron hopping frequency involved, it raises the prospect of terahertz tunability of magnetic coupling. PMID:26980456

  16. Long-Range Reconnaissance Imager on New Horizons

    NASA Astrophysics Data System (ADS)

    Cheng, A. F.; Weaver, H. A.; Conard, S. J.; Morgan, M. F.; Barnouin-Jha, O.; Boldt, J. D.; Cooper, K. A.; Darlington, E. H.; Grey, M. P.; Hayes, J. R.; Kosakowski, K. E.; Magee, T.; Rossano, E.; Sampath, D.; Schlemm, C.; Taylor, H. W.

    2008-10-01

    The LOng-Range Reconnaissance Imager (LORRI) is the high-resolution imaging instrument for the New Horizons mission to Pluto, its giant satellite Charon, its small moons Nix and Hydra, and the Kuiper Belt, which is the vast region of icy bodies extending roughly from Neptune’s orbit out to 50 astronomical units (AU). New Horizons launched on January 19, 2006, as the inaugural mission in NASA’s New Frontiers program. LORRI is a narrow-angle (field of view=0.29°), high-resolution (4.95 μrad pixels), Ritchey-Chrétien telescope with a 20.8-cm diameter primary mirror, a focal length of 263 cm, and a three-lens, field-flattening assembly. A 1,024×1,024 pixel (optically active region), thinned, backside-illuminated charge-coupled device (CCD) detector is used in the focal plane unit and is operated in frame-transfer mode. LORRI provides panchromatic imaging over a bandpass that extends approximately from 350 nm to 850 nm. LORRI operates in an extreme thermal environment, situated inside the warm spacecraft with a large, open aperture viewing cold space. LORRI has a silicon carbide optical system, designed to maintain focus over the operating temperature range without a focus adjustment mechanism. Moreover, the spacecraft is thruster-stabilized without reaction wheels, placing stringent limits on the available exposure time and the optical throughput needed to satisfy the measurement requirements.

  17. Long-range epidemic spreading in a random environment

    NASA Astrophysics Data System (ADS)

    Juhász, Róbert; Kovács, István A.; Iglói, Ferenc

    2015-03-01

    Modeling long-range epidemic spreading in a random environment, we consider a quenched, disordered, d -dimensional contact process with infection rates decaying with distance as 1 /rd +σ . We study the dynamical behavior of the model at and below the epidemic threshold by a variant of the strong-disorder renormalization-group method and by Monte Carlo simulations in one and two spatial dimensions. Starting from a single infected site, the average survival probability is found to decay as P (t ) ˜t-d /z up to multiplicative logarithmic corrections. Below the epidemic threshold, a Griffiths phase emerges, where the dynamical exponent z varies continuously with the control parameter and tends to zc=d +σ as the threshold is approached. At the threshold, the spatial extension of the infected cluster (in surviving trials) is found to grow as R (t ) ˜t1 /zc with a multiplicative logarithmic correction and the average number of infected sites in surviving trials is found to increase as Ns(t ) ˜(lnt) χ with χ =2 in one dimension.

  18. Long-range epidemic spreading in a random environment.

    PubMed

    Juhász, Róbert; Kovács, István A; Iglói, Ferenc

    2015-03-01

    Modeling long-range epidemic spreading in a random environment, we consider a quenched, disordered, d-dimensional contact process with infection rates decaying with distance as 1/rd+σ. We study the dynamical behavior of the model at and below the epidemic threshold by a variant of the strong-disorder renormalization-group method and by Monte Carlo simulations in one and two spatial dimensions. Starting from a single infected site, the average survival probability is found to decay as P(t)∼t-d/z up to multiplicative logarithmic corrections. Below the epidemic threshold, a Griffiths phase emerges, where the dynamical exponent z varies continuously with the control parameter and tends to zc=d+σ as the threshold is approached. At the threshold, the spatial extension of the infected cluster (in surviving trials) is found to grow as R(t)∼t1/zc with a multiplicative logarithmic correction and the average number of infected sites in surviving trials is found to increase as Ns(t)∼(lnt)χ with χ=2 in one dimension.

  19. Deep seafloor arrivals in long range ocean acoustic propagation.

    PubMed

    Stephen, Ralph A; Bolmer, S Thompson; Udovydchenkov, Ilya A; Worcester, Peter F; Dzieciuch, Matthew A; Andrew, Rex K; Mercer, James A; Colosi, John A; Howe, Bruce M

    2013-10-01

    Ocean bottom seismometer observations at 5000 m depth during the long-range ocean acoustic propagation experiment in the North Pacific in 2004 show robust, coherent, late arrivals that are not readily explained by ocean acoustic propagation models. These "deep seafloor" arrivals are the largest amplitude arrivals on the vertical particle velocity channel for ranges from 500 to 3200 km. The travel times for six (of 16 observed) deep seafloor arrivals correspond to the sea surface reflection of an out-of-plane diffraction from a seamount that protrudes to about 4100 m depth and is about 18 km from the receivers. This out-of-plane bottom-diffracted surface-reflected energy is observed on the deep vertical line array about 35 dB below the peak amplitude arrivals and was previously misinterpreted as in-plane bottom-reflected surface-reflected energy. The structure of these arrivals from 500 to 3200 km range is remarkably robust. The bottom-diffracted surface-reflected mechanism provides a means for acoustic signals and noise from distant sources to appear with significant strength on the deep seafloor.

  20. Long-range interactions between rubidium and potassium Rydberg atoms

    NASA Astrophysics Data System (ADS)

    Samboy, Nolan

    2017-03-01

    We investigate the long-range, two-body interactions between rubidium and potassium atoms in highly excited (n =70 ) Rydberg states. After establishing properly symmetrized asymptotic basis states, we diagonalize an interaction Hamiltonian consisting of the standard Coulombic potential expansion and atomic fine structure to calculate electronic potential energy curves. We find that when both atoms are excited to either the 70 s state or the 70 p state, both the Ω =0+ symmetry interactions and the Ω =0- symmetry interactions demonstrate a deep potential well capable of supporting many bound levels; the sizes of the corresponding dimer states are of the order of 2.25 μ m . We establish n -scaling relations for the equilibrium separation Re and the dissociation energy De and find these relations to be consistent with similar calculations involving the homonuclear interactions between rubidium and cesium. We discuss the specific effects of ℓ mixing and the exact composition of the calculated potential well via the expansion coefficients of the asymptotic basis states. Finally, we apply a Landau-Zener treatment to show that the dimer states are stable with respect to predissociation.

  1. Long-range spin Seebeck effect and acoustic spin pumping.

    PubMed

    Uchida, K; Adachi, H; An, T; Ota, T; Toda, M; Hillebrands, B; Maekawa, S; Saitoh, E

    2011-10-01

    Imagine that a metallic wire is attached to a part of a large insulator, which itself exhibits no magnetization. It seems impossible for electrons in the wire to register where the wire is positioned on the insulator. Here we found that, using a Ni₈₁Fe₁₉/Pt bilayer wire on an insulating sapphire plate, electrons in the wire recognize their position on the sapphire. Under a temperature gradient in the sapphire, surprisingly, the voltage generated in the Pt layer is shown to reflect the wire position, although the wire is isolated both electrically and magnetically. This non-local voltage is due to the coupling of spins and phonons: the only possible carrier of information in this system. We demonstrate this coupling by directly injecting sound waves, which realizes the acoustic spin pumping. Our finding provides a persuasive answer to the long-range nature of the spin Seebeck effect, and it opens the door to 'acoustic spintronics' in which sound waves are exploited for constructing spin-based devices.

  2. Long-range interactions between DNA-bound ligands.

    PubMed

    Samuelson, P; Jansen, K; Kubista, M

    1994-09-01

    We have studied the interaction of the A:T specific minor-groove binding ligand 4',6-diamidino-2-phenylindole (DAPI) with synthetic DNA oligomers containing specific binding sites in order to investigate possible long-range interactions between bound ligands. We find that DAPI binds cooperatively to the oligomers. The degree of cooperativity increases with increasing number of binding sites and decreases with the separation between them. This dependence is paralleled by changes in the induced circular dichroism spectrum of DAPI, which decreases in intensity at 335 nm and increases at 365 nm. These results are consistent with an allosteric interaction of DAPI with DNA, where bound ligands cooperatively alter the structure of the DNA molecule. This structural change seems possible to induce under various conditions, including physiological. One consequence of allosteric binding is that ligands bound at a distance from each other sense each other's presence and influence each others' properties. If some regulatory proteins induce the same conformational change as DAPI, novel mechanisms for controlling gene expression can be anticipated.

  3. Entropy production in systems with long range interactions

    NASA Astrophysics Data System (ADS)

    Pakter, Renato; Levin, Yan

    2017-04-01

    On a fine grained scale the Gibbs entropy of an isolated system remains constant throughout its dynamical evolution. This is a consequence of Liouville’s theorem for Hamiltonian systems and appears to contradict the second law of thermodynamics. In reality, however, there is no problem since the thermodynamic entropy should be associated with the Boltzmann entropy, which for non-equilibrium systems is different from Gibbs entropy. The Boltzmann entropy accounts for the microstates which are not accessible from a given initial condition, but are compatible with a given macrostate. In a sense the Boltzmann entropy is a coarse grained version of the Gibbs entropy and will not decrease during the dynamical evolution of a macroscopic system. In this paper we will explore the entropy production for systems with long range interactions. Unlike for short range systems, in the thermodynamic limit, the probability density function for these systems decouples into a product of one particle distribution functions and the coarse grained entropy can be calculated explicitly. We find that the characteristic time for the entropy production scales with the number of particles as {{N}α} , with α >0 , so that in the thermodynamic limit entropy production takes an infinite amount of time.

  4. Functional Sites Induce Long-Range Evolutionary Constraints in Enzymes

    PubMed Central

    Jack, Benjamin R.; Meyer, Austin G.; Echave, Julian; Wilke, Claus O.

    2016-01-01

    Functional residues in proteins tend to be highly conserved over evolutionary time. However, to what extent functional sites impose evolutionary constraints on nearby or even more distant residues is not known. Here, we report pervasive conservation gradients toward catalytic residues in a dataset of 524 distinct enzymes: evolutionary conservation decreases approximately linearly with increasing distance to the nearest catalytic residue in the protein structure. This trend encompasses, on average, 80% of the residues in any enzyme, and it is independent of known structural constraints on protein evolution such as residue packing or solvent accessibility. Further, the trend exists in both monomeric and multimeric enzymes and irrespective of enzyme size and/or location of the active site in the enzyme structure. By contrast, sites in protein–protein interfaces, unlike catalytic residues, are only weakly conserved and induce only minor rate gradients. In aggregate, these observations show that functional sites, and in particular catalytic residues, induce long-range evolutionary constraints in enzymes. PMID:27138088

  5. On long-range forces of repulsion between biological cells

    NASA Astrophysics Data System (ADS)

    Derjaguin, B. V.; Golovanov, M. V.

    1992-05-01

    We have established experimentally that when biological cells, for example, blood, are suspended in concentrated solutions of inorganic electrolytes (for instance, in a 15% solution of sodium chloride) then around some cells (leucocytes, especially tumour cells) there form haloes, i.e., circular spaces free from background cells (erythrocytes, yeast cells, colloidal particles of Indian ink). In the medium made up of erythrocytes the haloes form during 5-10 min as a result of the background cells drawing apart from the central halo-forming cell (HFC) at a distance of 10-100 μm and more. In the medium made of the Indian ink particles, the haloes form during 2-4 s and attain a thickness of about 10-20 μm. The erythrocytes and the haloes forming in their medium can be preserved for about three to five days at room temperature. It has been established that, when tumour HFCs are present at sufficient concentrations, they form hexagonal periodic structures having a mean spacing between cells of up to 60 μm. The authors put forward as one probable suggestion that the formation of haloes is largely determined by long-range repulsive forces arising from the phenomenon of diffusiophoresis generated by the diffusion currents that emerge from the surface of halo-forming cells.

  6. Lifetimes of ultra-long-range strontium Rydberg molecules

    NASA Astrophysics Data System (ADS)

    Camargo, F.; Whalen, J. Â. D.; Ding, R.; Sadeghpour, H. R.; Yoshida, S.; Burgdörfer, J.; Dunning, F. B.; Killian, T. C.

    2016-02-01

    The lifetimes of the lower-lying vibrational states of ultra-long-range strontium Rydberg molecules comprising one ground-state 5 s2 1S0 atom and one Rydberg atom in the 5 s 38 s 3S1 state are reported. The molecules are created in an ultracold gas held in an optical dipole trap and their numbers determined using field ionization, the product electrons being detected by a microchannel plate. The measurements show that, in marked contrast to earlier measurements involving rubidium Rydberg molecules, the lifetimes of the low-lying molecular vibrational states are very similar to those of the parent Rydberg atoms. This results because the strong p -wave resonance in low-energy electron-rubidium scattering, which strongly influences the rubidium molecular lifetimes, is not present for strontium. The absence of this resonance offers advantages for experiments involving strontium Rydberg atoms as impurities in quantum gases and for testing of theories of molecular formation and decay.

  7. Long range attraction between two different likely charged macroions

    NASA Astrophysics Data System (ADS)

    Shklovskii, B. I.

    2005-03-01

    It is known that in a water solution two likely charged macroions can attract each other due to correlations of multivalent counterions adsorbed on their surfaces [1]. This attraction is short-ranged and decays exponentially with distance between macroions. In this work, we show that a longer range attraction exists when the bare surface charge densities of the two macroions have the same sign but different in absolute values. The key idea is that with adsorbed multivalent counterions, two such macroions can be considered as conductors with fixed but different electric potentials. Each potential is determined by the difference between the entropic bulk chemical potential of a multivalent counterion and its correlation chemical potential determined by the bare surface charge density of the macroion. When the two macroions are close enough, their adjacent spots form a charged capacitor, which leads to attraction. This attraction is long-ranged: it decays with distance as a power law. This attractive force may play a important role in gene delivery, in which poly-cations are used to invert the charge of negative DNA so that it is not repelled by negative charged cell membrane. The attraction discussed above makes sure that even the charge of the membrane is also inverted, DNA may still be attracted to it. [1] I. Rouzina and V. A. Bloomfield, J. Phys. Chem. 100, 9977 (1996).

  8. Long-range interacting systems in the unconstrained ensemble

    NASA Astrophysics Data System (ADS)

    Latella, Ivan; Pérez-Madrid, Agustín; Campa, Alessandro; Casetti, Lapo; Ruffo, Stefano

    2017-01-01

    Completely open systems can exchange heat, work, and matter with the environment. While energy, volume, and number of particles fluctuate under completely open conditions, the equilibrium states of the system, if they exist, can be specified using the temperature, pressure, and chemical potential as control parameters. The unconstrained ensemble is the statistical ensemble describing completely open systems and the replica energy is the appropriate free energy for these control parameters from which the thermodynamics must be derived. It turns out that macroscopic systems with short-range interactions cannot attain equilibrium configurations in the unconstrained ensemble, since temperature, pressure, and chemical potential cannot be taken as a set of independent variables in this case. In contrast, we show that systems with long-range interactions can reach states of thermodynamic equilibrium in the unconstrained ensemble. To illustrate this fact, we consider a modification of the Thirring model and compare the unconstrained ensemble with the canonical and grand-canonical ones: The more the ensemble is constrained by fixing the volume or number of particles, the larger the space of parameters defining the equilibrium configurations.

  9. Measured long-range repulsive Casimir–Lifshitz forces

    PubMed Central

    Munday, J. N.; Capasso, Federico; Parsegian, V. Adrian

    2014-01-01

    Quantum fluctuations create intermolecular forces that pervade macroscopic bodies1–3. At molecular separations of a few nanometres or less, these interactions are the familiar van der Waals forces4. However, as recognized in the theories of Casimir, Polder and Lifshitz5–7, at larger distances and between macroscopic condensed media they reveal retardation effects associated with the finite speed of light. Although these long-range forces exist within all matter, only attractive interactions have so far been measured between material bodies8–11. Here we show experimentally that, in accord with theoretical prediction12, the sign of the force can be changed from attractive to repulsive by suitable choice of interacting materials immersed in a fluid. The measured repulsive interaction is found to be weaker than the attractive. However, in both cases the magnitude of the force increases with decreasing surface separation. Repulsive Casimir–Lifshitz forces could allow quantum levitation of objects in a fluid and lead to a new class of switchable nanoscale devices with ultra-low static friction13–15. PMID:19129843

  10. ORNL long-range environmental and waste management plan

    SciTech Connect

    Baldwin, J.S.; Bates, L.D.; Brown, C.H.; Easterday, C.A.; Hill, L.G.; Kendrick, C.M.; McNeese, L.E.; Myrick, T.E.; Payne, T.L.; Pepper, C.E.; Robinson, S.M.; Rohwer, P.S.; Scanlan, T.F.; Smith, M.A.; Stratton, L.E.; Trabalka, J.R.

    1989-09-01

    This report, the ORNL Long-Range Environmental and Waste Management Plan, is the annual update in a series begun in fiscal year 1985. Its primary purpose is to provide a thorough and systematic planning document to reflect the continuing process of site assessment, strategy development, and planning for the current and long-term control of environmental issues, waste management practices, and remedial action requirements. The document also provides an estimate of the resources required to implement the current plan. This document is not intended to be a budget document; it is, however, intended to provide guidance to both Martin Marietta Energy Systems, Inc., and the US Department of Energy (DOE) management as to the near order of magnitude of the resources (primarily funding requirements) and the time frame required to execute the strategy in the present revision of the plan. As with any document of this nature, the near-term (one to three years) part of the plan is a pragmatic assessment of the current program and ongoing capital projects and reflects the efforts perceived to be necessary to comply with all current state and federal regulations and DOE orders. It also should be in general agreement with current budget (funding) requests and obligations for these immediate years. 55 figs., 72 tabs.

  11. 25 CFR 170.410 - What is the purpose of tribal long-range transportation planning?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false What is the purpose of tribal long-range transportation... Program Facilities Long-Range Transportation Planning § 170.410 What is the purpose of tribal long-range transportation planning? (a) The purpose of long-range transportation planning is to clearly demonstrate a...

  12. 25 CFR 170.410 - What is the purpose of tribal long-range transportation planning?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 1 2013-04-01 2013-04-01 false What is the purpose of tribal long-range transportation... Program Facilities Long-Range Transportation Planning § 170.410 What is the purpose of tribal long-range transportation planning? (a) The purpose of long-range transportation planning is to clearly demonstrate a...

  13. 25 CFR 170.411 - What may a long-range transportation plan include?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 1 2012-04-01 2011-04-01 true What may a long-range transportation plan include? 170.411... Long-Range Transportation Planning § 170.411 What may a long-range transportation plan include? A comprehensive long-range transportation plan may include: (a) An evaluation of a full range of...

  14. 25 CFR 170.410 - What is the purpose of tribal long-range transportation planning?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 1 2012-04-01 2011-04-01 true What is the purpose of tribal long-range transportation... Program Facilities Long-Range Transportation Planning § 170.410 What is the purpose of tribal long-range transportation planning? (a) The purpose of long-range transportation planning is to clearly demonstrate a...

  15. 25 CFR 170.411 - What may a long-range transportation plan include?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false What may a long-range transportation plan include? 170... Long-Range Transportation Planning § 170.411 What may a long-range transportation plan include? A comprehensive long-range transportation plan may include: (a) An evaluation of a full range of...

  16. 25 CFR 170.411 - What may a long-range transportation plan include?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 1 2013-04-01 2013-04-01 false What may a long-range transportation plan include? 170... Long-Range Transportation Planning § 170.411 What may a long-range transportation plan include? A comprehensive long-range transportation plan may include: (a) An evaluation of a full range of...

  17. Universal Long Ranged Correlations in Driven Binary Mixtures

    NASA Astrophysics Data System (ADS)

    Poncet, Alexis; Bénichou, Olivier; Démery, Vincent; Oshanin, Gleb

    2017-03-01

    When two populations of "particles" move in opposite directions, like oppositely charged colloids under an electric field or intersecting flows of pedestrians, they can move collectively, forming lanes along their direction of motion. The nature of this "laning transition" is still being debated and, in particular, the pair correlation functions, which are the key observables to quantify this phenomenon, have not been characterized yet. Here, we determine the correlations using an analytical approach based on a linearization of the stochastic equations for the density fields, which is valid for dense systems of soft particles. We find that the correlations decay algebraically along the direction of motion, and have a self-similar exponential profile in the transverse direction. Brownian dynamics simulations confirm our theoretical predictions and show that they also hold beyond the validity range of our analytical approach, pointing to a universal behavior.

  18. Roles of Long-Range Tertiary Interactions in Limiting Dynamics of the Tetrahymena Group I Ribozyme

    PubMed Central

    2015-01-01

    We determined the effects of mutating the long-range tertiary contacts of the Tetrahymena group I ribozyme on the dynamics of its substrate helix (referred to as P1) and on catalytic activity. Dynamics were assayed by fluorescence anisotropy of the fluorescent base analogue, 6-methyl isoxanthopterin, incorporated into the P1 helix, and fluorescence anisotropy and catalytic activity were measured for wild type and mutant ribozymes over a range of conditions. Remarkably, catalytic activity correlated with P1 anisotropy over 5 orders of magnitude of activity, with a correlation coefficient of 0.94. The functional and dynamic effects from simultaneous mutation of the two long-range contacts that weaken P1 docking are cumulative and, based on this RNA’s topology, suggest distinct underlying origins for the mutant effects. Tests of mechanistic predictions via single molecule FRET measurements of rate constants for P1 docking and undocking suggest that ablation of the P14 tertiary interaction frees P2 and thereby enhances the conformational space explored by the undocked attached P1 helix. In contrast, mutation of the metal core tertiary interaction disrupts the conserved core into which the P1 helix docks. Thus, despite following a single correlation, the two long-range tertiary contacts facilitate P1 helix docking by distinct mechanisms. These results also demonstrate that a fluorescence anisotropy probe incorporated into a specific helix within a larger RNA can report on changes in local helical motions as well as differences in more global dynamics. This ability will help uncover the physical properties and behaviors that underlie the function of RNAs and RNA/protein complexes. PMID:24738560

  19. Precise long-range migration results from short-range stepwise migration during ring gland organogenesis.

    PubMed

    Sánchez-Higueras, Carlos; Hombría, James Castelli-Gair

    2016-06-01

    Many organs are specified far from the location they occupy when functional, having to migrate long distances through the heterogeneous and dynamic environment of the early embryo. We study the formation of the main Drosophila endocrine organ, the ring gland, as a new model to investigate in vivo the genetic regulation of collective cell migration. The ring gland results from the fusion of three independent gland primordia that migrate from the head towards the anterior aorta as the embryo is experiencing major morphogenetic movements. To complete their long-range migration, the glands extend filopodia moving sequentially towards a nearby intermediate target and from there to more distal ones. Thus, the apparent long-range migration is composed of several short-range migratory steps that facilitate reaching the final destination. We find that the target tissues react to the gland's proximity by sending filopodia towards it. Our finding of a succession of independent migration stages is consistent with the stepwise evolution of ring gland assembly and fits with the observed gland locations found in extant crustaceans, basal insects and flies.

  20. Geometrical computations explain projection patterns of long-range horizontal connections in visual cortex.

    PubMed

    Ben-Shahar, Ohad; Zucker, Steven

    2004-03-01

    Neurons in primary visual cortex respond selectively to oriented stimuli such as edges and lines. The long-range horizontal connections between them are thought to facilitate contour integration. While many physiological and psychophysical findings suggest that collinear or association field models of good continuation dictate particular projection patterns of horizontal connections to guide this integration process, significant evidence of interactions inconsistent with these hypotheses is accumulating. We first show that natural random variations around the collinear and association field models cannot account for these inconsistencies, a fact that motivates the search for more principled explanations. We then develop a model of long-range projection fields that formalizes good continuation based on differential geometry. The analysis implicates curvature(s) in a fundamental way, and the resulting model explains both consistent data and apparent outliers. It quantitatively predicts the (typically ignored) spread in projection distribution, its nonmonotonic variance, and the differences found among individual neurons. Surprisingly, and for the first time, this model also indicates that texture (and shading) continuation can serve as alternative and complementary functional explanations to contour integration. Because current anatomical data support both (curve and texture) integration models equally and because both are important computationally, new testable predictions are derived to allow their differentiation and identification.

  1. Emergence of a collective crystal in a classical system with long-range interactions

    NASA Astrophysics Data System (ADS)

    Turchi, Alessio; Fanelli, Duccio; Leoncini, Xavier

    2015-08-01

    A one-dimensional long-range model of classical rotators with an extended degree of complexity, as compared to paradigmatic long-range systems, is introduced and studied. Working at constant density, in the thermodynamic limit one can prove the statistical equivalence with the Hamiltonian mean-field (HMF) model and α-HMF: a second-order phase transition is indeed observed at the critical energy threshold \\varepsilon_c=0.75 . Conversely, when the thermodynamic limit is performed at infinite density (while keeping the length of the hosting interval L constant), the critical energy \\varepsilonc is modulated as a function of L. At low energy, a self-organized collective crystal phase is reported to emerge, which converges to a perfect crystal in the limit ε → 0 . To analyze the phenomenon, the equilibrium one-particle density function is analytically computed by maximizing the entropy. The transition and the associated critical energy between the gaseous and the crystal phase is computed. Molecular dynamics show that the crystal phase is apparently split into two distinct regimes, depending on the energy per particle ε. For small ε, particles are exactly located on the lattice sites; above an energy threshold \\varepsilon{*} , particles can travel from one site to another. However, \\varepsilon{*} does not signal a phase transition but reflects the finite time of observation: the perfect crystal observed for \\varepsilon >0 corresponds to a long-lasting dynamical transient, whose lifetime increases when the \\varepsilon >0 approaches zero.

  2. Engineering Technology Division Long-Range Plan, 1991--1995

    SciTech Connect

    Not Available

    1995-01-01

    This Engineering Technology Division Long-Range Plan is a departure from planning processes of the past. About a year ago we decided to approach our strategic planning in a very different way. With this plan we complete the first phase of a comprehensive process that has involved most of the Division staff. Through a series of brainstorming''meetings, we have accumulated a wealth of ideas. By this process, we have been able to identify our perceived strengths and weaknesses and to propose very challenging goals for the future. Early on in our planning, we selected two distinct areas where we desire changes. First, we want to pursue program development in a much more structured and dynamic manner: deciding what we want to do, developing plans, and providing the resources to follow through. Second, we want to change the way that we do business by developing more effective ways to work together within the Division and with the important groups that we interact with throughout Energy Systems. These initiatives are reflected in the plan and in related actions that the Division is implementing. The ETD mission is to perform research, development, conceptual design, analysis, fabrication, testing, and system demonstration of technology essential for (1) nuclear reactor systems and related technologies (2) space and defense systems (3) advanced systems for energy conversion and utilization, and (4) water and waste management systems, and to foster a vigorous program of technology transfer using the best available techniques of technical infusion into the marketplace. In meeting this mission, the Division will institute a documented pollution prevention program, ensure that environmental impact statements are prepared for the supporting program, and adhere to all environmental safety and health requirements. 4 figs., 2 tabs.

  3. Device Applications of Long-Range Surface Plasmons

    NASA Astrophysics Data System (ADS)

    Richards, John David

    Device applications of surface plasmons have been the subject of much interest since the introduction of surface plasmon biosensors in the early 1980's. A less well known coupled surface plasmon mode, called the long range surface plasmon (LRSP), exhibits lower loss and larger electric field enhancement than the surface plasmon (SP) mode. As a result, the LRSP mode has the potential to produce devices with better performance than the corresponding SP devices. In this thesis, the use of the LRSP mode in sensor and light modulator applications is theoretically and experimentally investigated. LRSP sensors are compared with SP sensors, both theoretically and experimentally. LRSP sensors offer greater design flexibility than SP sensors. In SP sensors, only the metal film thickness can be varied, as compared to LRSP sensors, where the thickness of the metal film and a dielectric coupling gap can be varied. Theoretical calculations indicate that LRSP sensors are more sensitive to changes in interfacial permittivity, both bulk refractive index changes and refractive index changes caused by the formation of dielectric overlayers on the metal film. Experimental measurements are performed to verify that LRSP sensors provide higher sensitivity than SP sensors. A theoretical comparison of reflection-mode modulators for free space optical interconnects is performed. Fabry -Perot (FP), SP, and LRSP polymeric electro-optic modulators are considered. The reflectance and modulation characteristics of these devices are determined using a model that accounts for anisotropic layered media. The sensitivity of the reflectance and modulation characteristics to parameters such as the collimation of the optical beam, the choice of metal film, the operating wavelength, and the temperature of the polymeric film, is analyzed for these modulator structures. SP and FP polymeric electro-optic modulators have already been experimentally demonstrated. The experimental feasibility of a LRSP

  4. Long range laser propagation: power scaling and beam quality issues

    NASA Astrophysics Data System (ADS)

    Bohn, Willy L.

    2010-09-01

    This paper will address long range laser propagation applications where power and, in particular beam quality issues play a major role. Hereby the power level is defined by the specific mission under consideration. I restrict myself to the following application areas: (1)Remote sensing/Space based LIDAR, (2) Space debris removal (3)Energy transmission, and (4)Directed energy weapons Typical examples for space based LIDARs are the ADM Aeolus ESA mission using the ALADIN Nd:YAG laser with its third harmonic at 355 nm and the NASA 2 μm Tm:Ho:LuLiF convectively cooled solid state laser. Space debris removal has attracted more attention in the last years due to the dangerous accumulation of debris in orbit which become a threat to the satellites and the ISS space station. High power high brightness lasers may contribute to this problem by partially ablating the debris material and hence generating an impulse which will eventually de-orbit the debris with their subsequent disintegration in the lower atmosphere. Energy transmission via laser beam from space to earth has long been discussed as a novel long term approach to solve the energy problem on earth. In addition orbital transfer and stationkeeping are among the more mid-term applications of high power laser beams. Finally, directed energy weapons are becoming closer to reality as corresponding laser sources have matured due to recent efforts in the JHPSSL program. All of this can only be realized if he laser sources fulfill the necessary power requirements while keeping the beam quality as close as possible to the diffraction limited value. And this is the rationale and motivation of this paper.

  5. a Global Model for Long-Range Interaction `DAMPING Functions'

    NASA Astrophysics Data System (ADS)

    Myatt, Philip Thomas; McCourt, Frederick R. W.; Le Roy, Robert J.

    2016-06-01

    In recent years, `damping functions', which characterize the weakening of inverse-power-sum long-range interatomic interaction energies with increasing electron overlap, have become an increasing important component of models for diatomic molecule interaction potentials. However, a key feature of models for damping functions, their portability, has received little scrutiny. The present work set out to examine all available ab initio induction and dispersion damping function data and to attempt to devise a `global' scheme for diatomic molecule damping functions. It appears that while neutral (H, He, Li, and Ne, homonuclear and mixed) and anion (H^- with H, He and Li) species obey (approximately) one common rule, proton plus neutral (H^+ with H, He and Li) and non-proton-cation plus neutral systems (He^+ and Li^+ with H, He and Li), must each be treated separately. However, for all three cases, a version of the Douketis-Scoles-Thakkar (ionization potential)power factor is a key scaling parameter. R.J. Le Roy, C. C. Haugen, J. Tao and Hui Li, Mol. Phys. 109,435 (2011). P.J. Knowles and W.J. Meath,J. Mol. Phys. 60, 1143 (1987); R.J. Wheatley and W.J. Meath,J. Mol. Phys. 80, 25 (1993); R.J. Wheatley and W.J. Meath J. Chem. Phys. 179, 341 (1994); R.J. Wheatley and W.J. Meath,J. Chem. Phys. 203, 209 (1996). C. Douketis,G. Scoles, S. Marchetti, M. Zen and A. J. Thakkar, J. Chem. Phys. 76, 3057 (1982).

  6. Numerical simulations of long-range pollutant transport from coast to inland mountainous regions

    SciTech Connect

    Yamada, Tetsuji; Bunker, S.S.; Niccum, E.

    1988-01-01

    Kurita and Ueda (1986) presented an example of the long-range transport of pollutants which frequently occurs in summer in Japan light gradient wind conditions. High concentrations of photochemical oxidants were observed in late evenings in the mountainous region approximately 160 km northwest from the large industrial zone located along the Tokyo bay. Pollutants were apparently transported by the large-scale circulations produced by the combination of southwesterly valley winds induced by thermal lows located in the mountain ranges, and southerly sea-breeze circulations in the Pacific Ocean coastal region (Kurita et al., 1985). We wish to stimulate and evaluate the relative importance of these circulations by using a time dependent, three-dimensional mesoscale model, HOTMAC, High Order Turbulence Model for Atmospheric Circulations. 7 refs., 4 figs.

  7. Thermal transport in the Fermi-Pasta-Ulam model with long-range interactions

    NASA Astrophysics Data System (ADS)

    Bagchi, Debarshee

    2017-03-01

    We study the thermal transport properties of the one-dimensional Fermi-Pasta-Ulam model (β type) with long-range interactions. The strength of the long-range interaction decreases with the (shortest) distance between the lattice sites as distance-δ, where δ ≥0 . Two Langevin heat baths at unequal temperatures are connected to the ends of the one-dimensional lattice via short-range harmonic interactions that drive the system away from thermal equilibrium. In the nonequilibrium steady state the heat current, thermal conductivity, and temperature profiles are computed by solving the equations of motion numerically. It is found that the conductivity κ has an interesting nonmonotonic dependence with δ with a maximum at δ =2.0 for this model. Moreover, at δ =2.0 ,κ diverges almost linearly with system size N and the temperature profile has a negligible slope, as one expects in ballistic transport for an integrable system. We demonstrate that the nonmonotonic behavior of the conductivity and the nearly ballistic thermal transport at δ =2.0 obtained under nonequilibrium conditions can be explained consistently by studying the variation of largest Lyapunov exponent λmax with δ , and excess energy diffusion in the equilibrium microcanonical system.

  8. A Comparative Analysis of the Performance of Long-Range Hypervelocity Vehicles

    NASA Technical Reports Server (NTRS)

    Eggers, Alfred J , Jr; Allen, H Julian; Neice, Stanford E

    1958-01-01

    Long-range hypervelocity vehicles are studied in terms of their motion in powered flight. Powered flight is analyzed for an idealized propulsion system which approximates rocket motors. Unpowered flight is characterized by a return to earth along a ballistic, skip, or glide trajectory. Only those trajectories are treated which yield the maximum range for a given velocity at the end of powered flight. Aerodynamic heating is treated in a manner similar to that employed previously by the senior authors in studying ballistic missiles (NACA rep. 1381), with the exception that radiant as well as convective heat transfer is considered in connection with glide and skip vehicles. As a final performance consideration, it is shown that on the basis of equal ratios of mass at take-off to mass at the end of powered flight, the hypervelocity vehicle compares favorably with the supersonic airplane for ranges in the neighborhood of and greater than one half the circumference of the earth. In the light of this and previous findings, it is concluded that the ballistic and glide vehicles have, in addition to the advantages usually ascribed to great speed, the attractive possibility of providing relatively efficient long-range flight.

  9. Amplitude equation and long-range interactions in underwater sand ripples in one dimension.

    PubMed

    Schnipper, Teis; Mertens, Keith; Ellegaard, Clive; Bohr, Tomas

    2008-10-01

    We present an amplitude equation for sand ripples under oscillatory flow in a situation where the sand is moving in a narrow channel and the height profile is practically one dimensional. The equation has the form ht = - epsilon(h-h)+((hx)2-1)hxx-hxxxx+delta((hx)2)xx which, due to the first term, is neither completely local (it has long-range coupling through the average height h) nor has local sand conservation. We argue that this is reasonable and show that the equation compares well with experimental observations in narrow channels. We focus in particular on the so-called doubling transition, a secondary instability caused by the sudden decrease in the amplitude of the water motion, leading to the appearance of a new ripple in each trough. This transition is well reproduced for sufficiently large delta (asymmetry between trough and crest). We finally present surprising experimental results showing that long-range coupling is indeed seen in the initial details of the doubling transition, where in fact two small ripples are initially formed, followed by global symmetry breaking removing one of them.

  10. Engineered long-range interactions on a 2D array of trapped ions

    NASA Astrophysics Data System (ADS)

    Britton, Joseph W.; Sawyer, Brian C.; Bollinger, John J.; Freericks, James K.

    2014-03-01

    Ising interactions are one paradigm used to model quantum magnetism in condensed matter systems. At NIST Boulder we confine and Doppler laser cool hundreds of 9Be+ ions in a Penning trap. The valence electron of each ion behaves as an ideal spin-1/2 particle and, in the limit of weak radial confinement relative to axial confinement, the ions naturally form a two-dimensional triangular lattice. A variable-range anti-ferromagnetic Ising interaction is engineered with a spin-dependent optical dipole force (ODF) through spin-dependent excitation of collective modes of ion motion. We have also exploited this spin-dependent force to perform spectroscopy and thermometry of the normal modes of the trapped ion crystal. The high spin-count and long-range spin-spin couplings achievable in the NIST Penning trap brings within reach simulation of computationally intractable problems in quantum magnetism. Examples include modeling quantum magnetic phase transitions and propagation of spin correlations resulting from a quantum quench. The Penning system may also be amenable to observation of spin-liquid behavior thought to arise in systems where the underlying lattice structure can frustrate long-range ordering. Supported by DARPA OLE and NIST.

  11. Short-range interactions versus long-range correlations in bird flocks

    NASA Astrophysics Data System (ADS)

    Cavagna, Andrea; Del Castello, Lorenzo; Dey, Supravat; Giardina, Irene; Melillo, Stefania; Parisi, Leonardo; Viale, Massimiliano

    2015-07-01

    Bird flocks are a paradigmatic example of collective motion. One of the prominent traits of flocking is the presence of long range velocity correlations between individuals, which allow them to influence each other over the large scales, keeping a high level of group coordination. A crucial question is to understand what is the mutual interaction between birds generating such nontrivial correlations. Here we use the maximum entropy (ME) approach to infer from experimental data of natural flocks the effective interactions between individuals. Compared to previous studies, we make a significant step forward as we retrieve the full functional dependence of the interaction on distance, and find that it decays exponentially over a range of a few individuals. The fact that ME gives a short-range interaction even though its experimental input is the long-range correlation function, shows that the method is able to discriminate the relevant information encoded in such correlations and single out a minimal number of effective parameters. Finally, we show how the method can be used to capture the degree of anisotropy of mutual interactions.

  12. Quantum phases from competing short- and long-range interactions in an optical lattice.

    PubMed

    Landig, Renate; Hruby, Lorenz; Dogra, Nishant; Landini, Manuele; Mottl, Rafael; Donner, Tobias; Esslinger, Tilman

    2016-04-28

    Insights into complex phenomena in quantum matter can be gained from simulation experiments with ultracold atoms, especially in cases where theoretical characterization is challenging. However, these experiments are mostly limited to short-range collisional interactions; recently observed perturbative effects of long-range interactions were too weak to reach new quantum phases. Here we experimentally realize a bosonic lattice model with competing short- and long-range interactions, and observe the appearance of four distinct quantum phases--a superfluid, a supersolid, a Mott insulator and a charge density wave. Our system is based on an atomic quantum gas trapped in an optical lattice inside a high-finesse optical cavity. The strength of the short-range on-site interactions is controlled by means of the optical lattice depth. The long (infinite)-range interaction potential is mediated by a vacuum mode of the cavity and is independently controlled by tuning the cavity resonance. When probing the phase transition between the Mott insulator and the charge density wave in real time, we observed a behaviour characteristic of a first-order phase transition. Our measurements have accessed a regime for quantum simulation of many-body systems where the physics is determined by the intricate competition between two different types of interactions and the zero point motion of the particles.

  13. Long-range correlations and nonstationarity in the Brazilian stock market

    NASA Astrophysics Data System (ADS)

    Costa, Rogério L.; Vasconcelos, G. L.

    2003-11-01

    We report an empirical study of the Ibovespa index of the São Paulo Stock Exchange in which we detect the existence of long-range correlations. To analyze our data, we introduce a rescaled variant of the usual detrended fluctuation analysis that allows us to obtain the Hurst exponent through a one-parameter fitting. We also compute a time-dependent Hurst exponent H( t) using 3-year moving time windows. In particular, we find that before the launch of the Collor Plan in 1990 the curve H( t) remains, in general, well above {1}/{2}, while afterwards it stays close to {1}/{2}. We thus argue that the structural reforms set off by the Collor Plan has lead to a more efficient stock market in Brazil. We also suggest that the time dependence of the Ibovespa Hurst exponent could be described in terms of a multifractional Brownian motion.

  14. Long-range correlations in a simple stochastic model of coupled transport

    NASA Astrophysics Data System (ADS)

    Larralde, Hernán; Sanders, David P.

    2009-08-01

    We study coupled transport in the nonequilibrium stationary state of a model consisting of independent random walkers, moving along a one-dimensional channel, which carry a conserved energy-like quantity, with density and temperature gradients imposed by reservoirs at the ends of the channel. In our model, walkers interact with other walkers at the same site by sharing energy at each time step, but the amount of energy carried does not affect the motion of the walkers. We find that already in this simple model long-range correlations arise in the nonequilibrium stationary state which are similar to those observed in more realistic models of coupled transport. We derive an analytical expression for the source of these correlations, which we use to obtain semi-analytical results for the correlations themselves assuming a local-equilibrium hypothesis. These are in very good agreement with results from direct numerical simulations.

  15. A method for simulating the atmospheric entry of long-range ballistic missiles

    NASA Technical Reports Server (NTRS)

    Eggers, A J , Jr

    1958-01-01

    It is demonstrated with the aid of similitude arguments that a model launched from a hypervelocity gun upstream through a special supersonic nozzle should experience aerodynamic heating and resulting thermal stresses like those encountered by a long-range ballistic missile entering the earth's atmosphere. This demonstration hinges on the requirements that model and missile be geometrically similar and made of the same material, and that they have the same flight speed and Reynolds number (based on conditions just outside the boundary layer) at corresponding points in their trajectories. The hypervelocity gun provides the model with the required initial speed, while the nozzle scales the atmosphere, in terms of density variation, to provide the model with speeds and Reynolds numbers over its entire trajectory. Since both the motion and aerodynamic heating of a missile tend to be simulated in the model tests, this combination of hypervelocity gun and supersonic nozzle is termed an atmosphere entry simulator.

  16. A comparison of optical architectures for constrained long-range imaging

    NASA Astrophysics Data System (ADS)

    Olson, S. Craig; Goodman, Timothy D.; Sparks, Andrew W.; Wheeler, Craig S.

    2017-05-01

    Long-range airborne full-motion-video systems require large apertures to maximize multiple aspects of system performance, including spatial resolution and sensitivity. As systems push to larger apertures for increased resolution and standoff range, both mounting constraints and atmospheric effects limit their effectiveness. This paper considers two questions: first, under what atmospheric and spectral conditions does it make sense to have a larger aperture; second, what types of optical systems can best exploit movement-constrained mounting? We briefly explore high-level atmospheric considerations in determining sensor aperture size for various spectral bands, following with a comparison of the swept-volume-to-aperture ratio of Ritchey-Chrétien and three-mirror-anastigmat optical systems.

  17. Long-range ordering of turbulent stresses in two-dimensional flow

    NASA Astrophysics Data System (ADS)

    Liao, Yang; Ouellette, Nicholas T.

    2015-06-01

    Using filter-space techniques, we study the spatial structure of the turbulent stress that couples motion on different length scales in a quasi-two-dimensional laboratory flow. As the length scale increases, we observe the appearance of long-range, system-spanning spatial order of this stress, even though the flow field remains disordered. Suggestively, this ordering occurs only in the range of scales over which we find net inverse energy transfer to larger scales. However, we find that a field built from wave vectors with random phases also displays ordering, suggesting that at least some of the ordering we observe is purely kinematic. Our results help to clarify the role played by geometric alignment in the turbulent energy cascade and highlight the importance of the scale-dependent rate of strain in the energy-transfer process.

  18. Transient Superdiffusion and Long-Range Correlations in the Motility Patterns of Trypanosomatid Flagellate Protozoa

    PubMed Central

    Alves, Luiz G. A.; Scariot, Débora B.; Guimarães, Renato R.; Nakamura, Celso V.; Mendes, Renio S.; Ribeiro, Haroldo V.

    2016-01-01

    We report on a diffusive analysis of the motion of flagellate protozoa species. These parasites are the etiological agents of neglected tropical diseases: leishmaniasis caused by Leishmania amazonensis and Leishmania braziliensis, African sleeping sickness caused by Trypanosoma brucei, and Chagas disease caused by Trypanosoma cruzi. By tracking the positions of these parasites and evaluating the variance related to the radial positions, we find that their motions are characterized by a short-time transient superdiffusive behavior. Also, the probability distributions of the radial positions are self-similar and can be approximated by a stretched Gaussian distribution. We further investigate the probability distributions of the radial velocities of individual trajectories. Among several candidates, we find that the generalized gamma distribution shows a good agreement with these distributions. The velocity time series have long-range correlations, displaying a strong persistent behavior (Hurst exponents close to one). The prevalence of “universal” patterns across all analyzed species indicates that similar mechanisms may be ruling the motion of these parasites, despite their differences in morphological traits. In addition, further analysis of these patterns could become a useful tool for investigating the activity of new candidate drugs against these and others neglected tropical diseases. PMID:27007779

  19. Long-range inversions for ocean acoustic tomography

    NASA Astrophysics Data System (ADS)

    Malanotte-Rizzoli, Paola

    1985-01-01

    Ocean acoustic tomography was proposed by Munk and Wunsch (1979) as a method for making measurements of ocean variability over large areas. After the successful demonstration of the feasibility of the idea in the 1981 three-dimensional mesoscale experiment (Ocean Tomography Group, 1982) the tomography group has proposed a new experiment to be carried out in 1986 in the eastern Pacific Ocean on ranges as long as the subtropical gyre scale. In this paper the gyre-scale experiment is simulated in the model ocean, using Holland's eddy-resolving general circulation quasi-geostrophic model. The paper addresses the following issues: (1) measurement of the heat content vertical profile horizontally averaged along the tomographic section; (2) adequacy of the linearized inverse over very long ranges and the need for its improvement; (3) possible improvements in the specification of the field statistics to obtain more accurate estimates and to measure properties like average pycnocline trends; (4) relationship of possible range-dependent information from the inversion to the assigned noise level. The results of the modeling simulation can be summarized as follows: (1) The linearized stochastic inversion needs to be improved for gyre-scale ranges providing estimates of the average heat content that have warm or cold biases. Iteration is used and shown to provide good estimates of the average heat content. (2) A smaller number of iterations is necessary if the initial estimate is improved. This can be done by including a spatial mean in the horizontal covariance function for regions of the ocean where the energy level in the mean and in the long length scales may be even more important than the mesoscale energy peak. (3) General trends like average pycnocline slopes can be estimated very well by including an inhomogeneous covariance in the inversion. (4) The estimates of the mean heat content values and of the average slopes are rather insensitive to the specified noise level

  20. Multifractal Geophysical Extremes: Nonstationarity and Long Range Correlations

    NASA Astrophysics Data System (ADS)

    Tchiguirinskaia, I.; Schertzer, D.; Lovejoy, S.

    2012-04-01

    Throughout the world, extremes in environmental sciences are of prime importance. They are key variables not only for risk assessments and engineering designs (e.g. of dams and bridges), but also for resource management (e.g. water and energy) and for land use. A better understanding of them is more and more indispensable in settling the debate on their possible climatological evolution. Whereas it took decades before a uniform technique for estimating flow frequencies within a stationary framework, it is often claimed that « stationarity is dead ! ». The fact that geophysical and environmental fields are variable over a wider range of scales than previously thought require to go beyond the limits of the (classical) Extreme Value Theory (EVT). Indeed, long-range correlations are beyond the scope of the classical EVT theory. We show that multifractal concepts and techniques are particularly appealing because they can effectively deal with a cascade of interactions concentrating for instance energy, liquid water, etc. into smaller and smaller space-time domains. Furthermore, a general outcome of these cascade processes -which surprisingly was realized only rather recently- is that rather independently of their details they yield probability distributions with power-law fall-offs, often called (asymptotic) Pareto or Zipf laws. We discuss the corresponding probability distributions of their maxima and its relationship with the Frechet law. We use these multifractal techniques to investigate the possibility of using very short or incomplete data records for reliable statistical predictions of the extremes. In particular we assess the multifractal parameter uncertainty with the help of long synthetic multifractal series and their sub-samples, in particular to obtain an approximation of confidence intervals that would be particularly important for the predictions of multifractal extremes. We finally illustrate the efficiency of this approach with its application to

  1. Long range electron transfer in helical polyproline II oligopeptides

    NASA Astrophysics Data System (ADS)

    Ogawa, Michael Y.; Moreira, Icaro; Wishart, James F.; Isied, Stephan S.

    1993-10-01

    A series of binuclear donor-acceptor complexes with helical polyproline bridges [(bpy) 2Ru IIL-(Pro) n-apy-Ru III(NH 3) 5] 5+, n = 6, 7, 9, where L = 4-carboxy-4'-methyl-2,2'-bipyridine, bpy = 4,4'-bipyridine, and apy = 4-aminopyridine, were synthesized and characterized by absorption spectra, electrochemistry and HPLC. The CD spectra of the complexes confirm that they exist in the helical polyproline II structure. Intramolecular electron transfer within these complexes was studied by generating the [(bpy) 2Ru IL ·-(Pro) n-apy-Ru III(NH 3) 5] intermediate from the reaction of eaq (from pulse radiolysis) with the [(bpy) 2Ru IIL-(Pro) n-apy-Ru III(NH 3) 5] species in aqueous solution. The driving force for this reaction is estimated to be |Δ G0| ≈ 1.5 V. The rates ( k, 25°C) and activation parameters (Δ H‡ (kcal/mol), Δ S‡ (eu)) for the intramolecular electron transfer were found to be: 1.08×10 5 s -1, 5.6, -17; 6.40 × 10 4 s -1, 5.1, -19; 1.91 × 10 4 s -1, 4.0, and -26 for n = 6, 7, 9 respectively. The rate ( k, 25°C) and activation parameters (Δ H‡ (kcal/mol), Δ S‡ (eu)) for the intermolecular reaction between [(bpy) 2Ru IL ·] and [(NH 3) 5Ru III-apy-Pro] were found to be 2.1 × 10 9 M -1 s -1, 3.3 and -5. This series extends our studies of the distance dependence of rate versus the number of helical prolines bridging a donor and acceptor ruthenium site to a metal-to-metal distance ≈ 40 Å. The weak dependence of rate versus the number of prolines observed for n = 6, 7, and 9 is very similar to that observed earlier for [(bpy) 2Ru IIL-(Pro) n-Co III(NH 3) 5], n = 4-6. The rapid rates observed at these long distances show that long range electron transfer can be observed between an appropriate donor and acceptor directly connected to the proline bridge via peptide bonds at distances similar to the diameter of a small protein.

  2. Long-range electron transfer in biomolecules. Tunneling or hopping?

    PubMed

    Voityuk, Alexander A

    2011-10-27

    Two competing mechanisms are relevant for long-range electron transfer (ET) in biomolecules: direct electron tunneling between donor (D) and acceptor (A), D → A, and multistep hopping D → X → A, where an electron or an electron hole is transiently localized on intermediate sites X. Which of these mechanisms dominates the ET reaction is determined by the arrangement and electronic properties of the redox centers. For thermal ET, it is shown that single-step tunneling is overcome by hopping when the energy gap E between D and X is smaller than the crossover barrier E(C), E(C) = (ΔG/2) + (3/4)k(B)TβR(DA), where ΔG is the driving force, β the decay parameter, and R(DA) the donor-acceptor distance. In proteins at T = 300 K, hopping will dominate when E < E(C) = (ΔG/2) + (R(DA)/50) (E and ΔG are in eV, R(DA) in Å); single-step tunneling will be operative when E > E(C). Thus, one can explore the ET mechanism using three quantities E, ΔG, and R(DA). When ΔG = 0 and E = 0.5 eV (the difference in redox potentials of D and X is 0.5 V), two-step hopping D → X → A will be favored at R(DA) >25 Å. In protein ET chains, the distance between redox cofactors is often smaller than 20 Å, but the gap E between the cofactors and surrounding amino acid residues is larger than 0.5 eV. Therefore, ET in the systems should occur by single-step tunneling D → A. In the activationless regime (ΔG ≈ -λ, λ is the reorganization energy) often observed for photoinduced ET, the crossing point energy is determined by E(C) = (2λkTβR(DA))(1/2) - λ. The suggested expressions for the threshold barrier may be useful to predict the ET mechanism in natural and artificial redox systems.

  3. Hydrodynamic interactions enhance gelation in dispersions of colloids with short-ranged attraction and long-ranged repulsion.

    PubMed

    Varga, Zsigmond; Swan, James

    2016-09-28

    We show that discrete element simulations of colloidal gelation must account for hydrodynamic interactions between suspended particles through investigation of gelation in a dispersion of colloids interacting pair-wise via short-ranged attraction and long-ranged repulsion (SALR). These dynamic simulations juxtapose self-assembly with and without hydrodynamic interactions between the particles. The long-ranged repulsion impacts the relative rates of coagulation and compaction of colloidal aggregates pre-gel, and introduces a surprising sensitivity to the nature of hydrodynamic interactions between the suspended colloids. For such SALR dispersions, we observe a significant disparity between the percolation boundaries predicted by simulations including and neglecting long-ranged hydrodynamic interactions. Additionally, we find that the percolation boundaries predicted by simulations including hydrodynamic interactions agree well with those measured experimentally. Long-ranged repulsion promotes gelation via growth of anisotropic clusters regardless of the hydrodynamic model employed. However, differences between the models, which persist far from the percolation boundary, are apparent via measurements of the fractal dimension, local bond order parameters, and the collective relaxation dynamics. Notably, the growth of elongated clusters is augmented in simulations that incorporate long-ranged hydrodynamic interactions due to the anisotropic diffusion of elongated bodies at low Reynolds numbers, which favors percolation over a transition of anisotropic clusters to their more isotropic ground states. It is only in relatively dense suspensions that a combination of hydrodynamic screening and significantly faster aggregation combine to bring the two simulation methods into agreement. These results demonstrate the necessity of long-ranged hydrodynamic forces in discrete element simulations of heterogeneous gelation at the colloidal scale.

  4. The long range voice coil atomic force microscope

    PubMed Central

    Barnard, H.; Randall, C.; Bridges, D.; Hansma, P. K.

    2012-01-01

    Most current atomic force microscopes (AFMs) use piezoelectric ceramics for scan actuation. Piezoelectric ceramics provide precision motion with fast response to applied voltage potential. A drawback to piezoelectric ceramics is their inherently limited ranges. For many samples this is a nonissue, as imaging the nanoscale details is the goal. However, a key advantage of AFM over other microscopy techniques is its ability to image biological samples in aqueous buffer. Many biological specimens have topography for which the range of piezoactuated stages is limiting, a notable example of which is bone. In this article, we present the use of voice coils in scan actuation for an actuation range in the Z-axis an order of magnitude larger than any AFM commercially available today. The increased scan size will allow for imaging an important new variety of samples, including bone fractures. PMID:22380097

  5. The long range voice coil atomic force microscope

    SciTech Connect

    Barnard, H.; Randall, C.; Bridges, D.; Hansma, P. K.

    2012-02-15

    Most current atomic force microscopes (AFMs) use piezoelectric ceramics for scan actuation. Piezoelectric ceramics provide precision motion with fast response to applied voltage potential. A drawback to piezoelectric ceramics is their inherently limited ranges. For many samples this is a nonissue, as imaging the nanoscale details is the goal. However, a key advantage of AFM over other microscopy techniques is its ability to image biological samples in aqueous buffer. Many biological specimens have topography for which the range of piezoactuated stages is limiting, a notable example of which is bone. In this article, we present the use of voice coils in scan actuation for an actuation range in the Z-axis an order of magnitude larger than any AFM commercially available today. The increased scan size will allow for imaging an important new variety of samples, including bone fractures.

  6. 2006 Long Range Development Plan Final Environmental ImpactReport

    SciTech Connect

    Philliber, Jeff

    2007-01-22

    This environmental impact report (EIR) has been prepared pursuant to the applicable provisions of the California Environmental Quality Act (CEQA) and its implementing guidelines (CEQA Guidelines), and the Amended University of California Procedures for Implementation of the California Environmental Quality Act (UC CEQA Procedures). The University of California (UC or the University) is the lead agency for this EIR, which examines the overall effects of implementation of the proposed 2006 Long Range Development Plan (LRDP; also referred to herein as the 'project' for purposes of CEQA) for Lawrence Berkeley National Laboratory (LBNL; also referred to as 'Berkeley Lab,' 'the Laboratory,' or 'the Lab' in this document). An LRDP is a land use plan that guides overall development of a site. The Lab serves as a special research campus operated by the University employees, but it is owned and financed by the federal government and as such it is distinct from the UC-owned Berkeley Campus. As a campus operated by the University of California, the Laboratory is required to prepare an EIR for an LRDP when one is prepared or updated pursuant to Public Resources Code Section 21080.09. The adoption of an LRDP does not constitute a commitment to, or final decision to implement, any specific project, construction schedule, or funding priority. Rather, the proposed 2006 LRDP describes an entire development program of approximately 980,000 gross square feet of new research and support space construction and 320,000 gross square feet of demolition of existing facilities, for a total of approximately 660,000 gross square feet of net new occupiable space for the site through 2025. Specific projects will undergo CEQA review at the time proposed to determine what, if any, additional review is necessary prior to approval. As described in Section 1.4.2, below, and in Chapter 3 of this EIR (the Project Description), the size of the project has been reduced since the Notice of Preparation for

  7. Controlled long-range interactions between Rydberg atoms and ions

    NASA Astrophysics Data System (ADS)

    Secker, T.; Gerritsma, R.; Glaetzle, A. W.; Negretti, A.

    2016-07-01

    We theoretically investigate trapped ions interacting with atoms that are coupled to Rydberg states. The strong polarizabilities of the Rydberg levels increase the interaction strength between atoms and ions by many orders of magnitude, as compared to the case of ground-state atoms, and may be mediated over micrometers. We calculate that such interactions can be used to generate entanglement between an atom and the motion or internal state of an ion. Furthermore, the ion could be used as a bus for mediating spin-spin interactions between atomic spins in analogy to much employed techniques in ion-trap quantum simulation. The proposed scheme comes with attractive features as it maps the benefits of the trapped-ion quantum system onto the atomic one without obviously impeding its intrinsic scalability. No ground-state cooling of the ion or atom is required and the setup allows for full dynamical control. Moreover, the scheme is to a large extent immune to the micromotion of the ion. Our findings are of interest for developing hybrid quantum information platforms and for implementing quantum simulations of solid-state physics.

  8. Motion.

    ERIC Educational Resources Information Center

    Brand, Judith, Ed.

    2002-01-01

    This issue of Exploratorium Magazine focuses on the topic of motion. Contents include: (1) "First Word" (Zach Tobias); (2) "Cosmic Collisions" (Robert Irion); (3) "The Mobile Cell" (Karen E. Kalumuck); (4) "The Paths of Paths" (Steven Vogel); (5) "Fragments" (Pearl Tesler); (6) "Moving Pictures" (Amy Snyder); (7) "Plants on the Go" (Katharine…

  9. Motion.

    ERIC Educational Resources Information Center

    Gerhart, James B.; Nussbaum, Rudi H.

    This monograph was written for the Conference on the New Instructional Materials in Physics held at the University of Washington in summer, 1965. It is intended for use in an introductory course in college physics. It consists of an extensive qualitative discussion of motion followed by a detailed development of the quantitative methods needed to…

  10. Motion.

    ERIC Educational Resources Information Center

    Brand, Judith, Ed.

    2002-01-01

    This issue of Exploratorium Magazine focuses on the topic of motion. Contents include: (1) "First Word" (Zach Tobias); (2) "Cosmic Collisions" (Robert Irion); (3) "The Mobile Cell" (Karen E. Kalumuck); (4) "The Paths of Paths" (Steven Vogel); (5) "Fragments" (Pearl Tesler); (6) "Moving Pictures" (Amy Snyder); (7) "Plants on the Go" (Katharine…

  11. An Approach to Long-Range Planning in the 1980's. AIR Forum 1981 Paper.

    ERIC Educational Resources Information Center

    Lueck, Lowell A.

    Key ingredients of long-range planning described in the literature during the last 10 years, the role of an office of institutional research, and a coordinated long-range planning process as it might occur in a public four-year college or university are described. A successful long-range planning process is characterized by centralized…

  12. An Approach to Long-Range Planning in the 1980's. AIR Forum 1981 Paper.

    ERIC Educational Resources Information Center

    Lueck, Lowell A.

    Key ingredients of long-range planning described in the literature during the last 10 years, the role of an office of institutional research, and a coordinated long-range planning process as it might occur in a public four-year college or university are described. A successful long-range planning process is characterized by centralized…

  13. 7 CFR 1717.604 - Long-range engineering plans and construction work plans.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 11 2011-01-01 2011-01-01 false Long-range engineering plans and construction work... AND GUARANTEED ELECTRIC LOANS Operational Controls § 1717.604 Long-range engineering plans and construction work plans. (a) All borrowers are required to maintain up-to-date long-range engineering plans and...

  14. 7 CFR 1717.604 - Long-range engineering plans and construction work plans.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 11 2013-01-01 2013-01-01 false Long-range engineering plans and construction work... AND GUARANTEED ELECTRIC LOANS Operational Controls § 1717.604 Long-range engineering plans and construction work plans. (a) All borrowers are required to maintain up-to-date long-range engineering plans and...

  15. 7 CFR 1717.604 - Long-range engineering plans and construction work plans.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 11 2014-01-01 2014-01-01 false Long-range engineering plans and construction work... AND GUARANTEED ELECTRIC LOANS Operational Controls § 1717.604 Long-range engineering plans and construction work plans. (a) All borrowers are required to maintain up-to-date long-range engineering plans and...

  16. 7 CFR 1717.604 - Long-range engineering plans and construction work plans.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 11 2010-01-01 2010-01-01 false Long-range engineering plans and construction work... AND GUARANTEED ELECTRIC LOANS Operational Controls § 1717.604 Long-range engineering plans and construction work plans. (a) All borrowers are required to maintain up-to-date long-range engineering plans and...

  17. 7 CFR 1717.604 - Long-range engineering plans and construction work plans.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 11 2012-01-01 2012-01-01 false Long-range engineering plans and construction work... AND GUARANTEED ELECTRIC LOANS Operational Controls § 1717.604 Long-range engineering plans and construction work plans. (a) All borrowers are required to maintain up-to-date long-range engineering plans and...

  18. A comparative analysis of the performance of long-range hypervelocity vehicles

    NASA Technical Reports Server (NTRS)

    Eggers, Alfred J , Jr; Allen, H Julian; Neice, Stanford E

    1955-01-01

    Long-range hypervelocity vehicles are studied in terms of their motion in powered flight, and their motion and aerodynamic heating in unpowered flight. Powered flight is analyzed for an idealized propulsion system which rather closely approaches present-day rocket motors. Unpowered flight is characterized by a return to earth along a ballistic, skip, or glide trajectory. Only those trajectories are treated which yield the maximum range for a given velocity at the end of powered flight. Aerodynamic heating is treated in a manner similar to that employed previously by the senior authors is studying ballistic missiles (NACA RM A53D28), with the exception that radiant as well as convective heat transfer is considered in connection with glide and skip vehicles. The ballistic vehicle is found to be the least efficient of the several types studied in the sense that it generally requires the highest velocity at the end of powered flight in order to attain a given range. This disadvantage may be offset, however, by reducing convective heat transfer to the re-entry body through the artifice of increasing pressure drag in relation to friction drag - that is, by using a blunt body. Thus the kinetic energy required by the vehicle at the end of powered flight may be reduced by minimizing the mass of coolant material involved.

  19. Long-range acoustic interactions in insect swarms: an adaptive gravity model

    NASA Astrophysics Data System (ADS)

    Gorbonos, Dan; Ianconescu, Reuven; Puckett, James G.; Ni, Rui; Ouellette, Nicholas T.; Gov, Nir S.

    2016-07-01

    The collective motion of groups of animals emerges from the net effect of the interactions between individual members of the group. In many cases, such as birds, fish, or ungulates, these interactions are mediated by sensory stimuli that predominantly arise from nearby neighbors. But not all stimuli in animal groups are short range. Here, we consider mating swarms of midges, which are thought to interact primarily via long-range acoustic stimuli. We exploit the similarity in form between the decay of acoustic and gravitational sources to build a model for swarm behavior. By accounting for the adaptive nature of the midges’ acoustic sensing, we show that our ‘adaptive gravity’ model makes mean-field predictions that agree well with experimental observations of laboratory swarms. Our results highlight the role of sensory mechanisms and interaction range in collective animal behavior. Additionally, the adaptive interactions that we present here open a new class of equations of motion, which may appear in other biological contexts.

  20. Long-range and rapid transport of individual nano-objects by a hybrid electrothermoplasmonic nanotweezer.

    PubMed

    Ndukaife, Justus C; Kildishev, Alexander V; Nnanna, Agbai George Agwu; Shalaev, Vladimir M; Wereley, Steven T; Boltasseva, Alexandra

    2016-01-01

    Plasmon-enhanced optical trapping is being actively studied to provide efficient manipulation of nanometre-sized objects. However, a long-standing issue with previously proposed solutions is how to controllably load the trap on-demand without relying on Brownian diffusion. Here, we show that the photo-induced heating of a nanoantenna in conjunction with an applied a.c. electric field can initiate rapid microscale fluid motion and particle transport with a velocity exceeding 10 μm s(-1), which is over two orders of magnitude faster than previously predicted. Our electrothermoplasmonic device enables on-demand long-range and rapid delivery of single nano-objects to specific plasmonic nanoantennas, where they can be trapped and even locked in place. We also present a physical model that elucidates the role of both heat-induced fluidic motion and plasmonic field enhancement in the plasmon-assisted optical trapping process. Finally, by applying a d.c. field or low-frequency a.c. field (below 10 Hz) while the particle is held in the trap by the gradient force, the trapped nano-objects can be immobilized into plasmonic hotspots, thereby providing the potential for effective low-power nanomanufacturing on-chip.

  1. Temporal limits of long-range phase discrimination across the visual field.

    PubMed

    Aghdaee, S Mehdi; Cavanagh, Patrick

    2007-07-01

    When two flickering sources are far enough apart to avoid low-level motion signals, phase judgment relies on the temporal individuation of the light and dark phases of each source. The highest rate at which the individuation can be maintained has been referred to as Gestalt flicker fusion [Van de Grind, W. A., Grüsser, O. -J., & Lunkenheimer, H. U. (1973). Temporal transfer properties of the afferent visual system. Psychophysical, neurophysiological and theoretical investigations. In R. Jung (Ed.), Handbook of sensory physiology (Vol. VII/3, pp. 431-573). Berlin: Springer, Chapter 7] and this has been taken as a measure of the temporal resolution of attention [Verstraten, F. A., Cavanagh, P., & Labianca, A. T. (2000). Limits of attentive tracking reveal temporal properties of attention. Vision Research, 40, 3651-3664; Battelli, L., Cavanagh, P., Intriligator, J., Tramo, M. J., Henaff, M. A., Michel, F., et al. (2001). Unilateral right parietal damage leads to bilateral deficit for high-level motion. Neuron, 32, 985-995]. Here we examine the variation of the temporal resolution of attention across the visual field using phase judgments of widely spaced pairs of flickering dots presented either in the upper or lower visual field and at either 4 degrees or 14 degrees eccentricity. We varied inter-dot separation to determine the spacing at which phase discriminations are no longer facilitated by low-level motion signals. Our data for these long-range phase judgments showed that temporal resolution decreases only slightly with increased distance from center of gaze (decrease from 11.4 to 8.9 Hz between 4 degrees to 14 degrees ), and does not differ between upper and lower visual fields. We conclude that the variation of the temporal limits of visual attention across the visual field differs markedly from that of the spatial resolution of attention.

  2. Sperm whale long-range echolocation sounds revealed by ANTARES, a deep-sea neutrino telescope

    PubMed Central

    André, M.; Caballé, A.; van der Schaar, M.; Solsona, A.; Houégnigan, L.; Zaugg, S.; Sánchez, A. M.; Castell, J. V.; Solé, M.; Vila, F.; Djokic, D.; Adrián-Martínez, S.; Albert, A.; Anghinolfi, M.; Anton, G.; Ardid, M.; Aubert, J.-J.; Avgitas, T.; Baret, B.; Barrios-Martí, J.; Basa, S.; Bertin, V.; Biagi, S.; Bormuth, R.; Bouwhuis, M. C.; Bruijn, R.; Brunner, J.; Busto, J.; Capone, A.; Caramete, L.; Carr, J.; Celli, S.; Chiarusi, T.; Circella, M.; Coleiro, A.; Coniglione, R.; Costantini, H.; Coyle, P.; Creusot, A.; Deschamps, A.; De Bonis, G.; Distefano, C.; Di Palma, I.; Donzaud, C.; Dornic, D.; Drouhin, D.; Eberl, T.; El Bojaddaini, I.; Elsässer, D.; Enzenhöfer, A.; Fehn, K.; Felis, I.; Fusco, L. A.; Galatà, S.; Gay, P.; Geißelsöder, S.; Geyer, K.; Giordano, V.; Gleixner, A.; Glotin, H.; Gracia-Ruiz, R.; Graf, K.; Hallmann, S.; van Haren, H.; Heijboer, A. J.; Hello, Y.; Hernandez-Rey, J. J.; Hößl, J.; Hofestädt, J.; Hugon, C.; Illuminati, G.; James, C. W.; de Jong, M.; Jongen, M.; Kadler, M.; Kalekin, O.; Katz, U.; Kießling, D.; Kouchner, A.; Kreter, M.; Kreykenbohm, I.; Kulikovskiy, V.; Lachaud, C.; Lahmann, R.; Lefèvre, D.; Leonora, E.; Loucatos, S.; Marcelin, M.; Margiotta, A.; Marinelli, A.; Martínez-Mora, J. A.; Mathieu, A.; Melis, K.; Michael, T.; Migliozzi, P.; Moussa, A.; Mueller, C.; Nezri, E.; Păvălaş, G. E.; Pellegrino, C.; Perrina, C.; Piattelli, P.; Popa, V.; Pradier, T.; Racca, C.; Riccobene, G.; Roensch, K.; Saldaña, M.; Samtleben, D. F. E.; Sanguineti, M.; Sapienza, P.; Schnabel, J.; Schüssler, F.; Seitz, T.; Sieger, C.; Spurio, M.; Stolarczyk, Th.; Sánchez-Losa, A.; Taiuti, M.; Trovato, A.; Tselengidou, M.; Turpin, D.; Tönnis, C.; Vallage, B.; Vallée, C.; Van Elewyck, V.; Vivolo, D.; Wagner, S.; Wilms, J.; Zornoza, J. D.; Zuñiga, J.

    2017-01-01

    Despite dedicated research has been carried out to adequately map the distribution of the sperm whale in the Mediterranean Sea, unlike other regions of the world, the species population status is still presently uncertain. The analysis of two years of continuous acoustic data provided by the ANTARES neutrino telescope revealed the year-round presence of sperm whales in the Ligurian Sea, probably associated with the availability of cephalopods in the region. The presence of the Ligurian Sea sperm whales was demonstrated through the real-time analysis of audio data streamed from a cabled-to-shore deep-sea observatory that allowed the hourly tracking of their long-range echolocation behaviour on the Internet. Interestingly, the same acoustic analysis indicated that the occurrence of surface shipping noise would apparently not condition the foraging behaviour of the sperm whale in the area, since shipping noise was almost always present when sperm whales were acoustically detected. The continuous presence of the sperm whale in the region confirms the ecological value of the Ligurian sea and the importance of ANTARES to help monitoring its ecosystems. PMID:28401960

  3. Plasmonic nanofabrication by long-range excitation transfer via DNA nanowire.

    PubMed

    Wirth, J; Garwe, F; Hähnel, G; Csáki, A; Jahr, N; Stranik, O; Paa, W; Fritzsche, W

    2011-04-13

    Driven by the demand for ongoing integration and increased complexity of today's microelectronic circuits, smaller and smaller structures need to be fabricated with a high throughput. In contrast to serial nanofabrication techniques, based, e.g., on electron beam or scanning probe methods, optical methods allow a parallel approach and thus a high throughput. However, they rarely reach the desired resolution. One example is plasmon lithography, which is limited by the utilized plasmonic metal structures. Here we show a new approach extending plasmonic lithography with the potential for a highly parallel nanofabrication with a higher level of complexity based on nanoantenna effects combined with molecular nanowires. Thereby femtosecond laser pulse light is converted by Ag nanoparticles into a high plasmonic excitation guided along attached DNA structures. An underlying poly(methyl methacrylate) (PMMA) layer acting as an electron-sensitive resist is so structured along the former DNA position. This apparently DNA-guided effect leads to nanometer grooves reaching even micrometers away from the excited nanoparticle, representing a novel effect of long-range excitation transfer along DNA nanowires.

  4. Sperm whale long-range echolocation sounds revealed by ANTARES, a deep-sea neutrino telescope.

    PubMed

    André, M; Caballé, A; van der Schaar, M; Solsona, A; Houégnigan, L; Zaugg, S; Sánchez, A M; Castell, J V; Solé, M; Vila, F; Djokic, D; Adrián-Martínez, S; Albert, A; Anghinolfi, M; Anton, G; Ardid, M; Aubert, J-J; Avgitas, T; Baret, B; Barrios-Martí, J; Basa, S; Bertin, V; Biagi, S; Bormuth, R; Bouwhuis, M C; Bruijn, R; Brunner, J; Busto, J; Capone, A; Caramete, L; Carr, J; Celli, S; Chiarusi, T; Circella, M; Coleiro, A; Coniglione, R; Costantini, H; Coyle, P; Creusot, A; Deschamps, A; De Bonis, G; Distefano, C; Di Palma, I; Donzaud, C; Dornic, D; Drouhin, D; Eberl, T; El Bojaddaini, I; Elsässer, D; Enzenhöfer, A; Fehn, K; Felis, I; Fusco, L A; Galatà, S; Gay, P; Geißelsöder, S; Geyer, K; Giordano, V; Gleixner, A; Glotin, H; Gracia-Ruiz, R; Graf, K; Hallmann, S; van Haren, H; Heijboer, A J; Hello, Y; Hernandez-Rey, J J; Hößl, J; Hofestädt, J; Hugon, C; Illuminati, G; James, C W; de Jong, M; Jongen, M; Kadler, M; Kalekin, O; Katz, U; Kießling, D; Kouchner, A; Kreter, M; Kreykenbohm, I; Kulikovskiy, V; Lachaud, C; Lahmann, R; Lefèvre, D; Leonora, E; Loucatos, S; Marcelin, M; Margiotta, A; Marinelli, A; Martínez-Mora, J A; Mathieu, A; Melis, K; Michael, T; Migliozzi, P; Moussa, A; Mueller, C; Nezri, E; Păvălaş, G E; Pellegrino, C; Perrina, C; Piattelli, P; Popa, V; Pradier, T; Racca, C; Riccobene, G; Roensch, K; Saldaña, M; Samtleben, D F E; Sanguineti, M; Sapienza, P; Schnabel, J; Schüssler, F; Seitz, T; Sieger, C; Spurio, M; Stolarczyk, Th; Sánchez-Losa, A; Taiuti, M; Trovato, A; Tselengidou, M; Turpin, D; Tönnis, C; Vallage, B; Vallée, C; Van Elewyck, V; Vivolo, D; Wagner, S; Wilms, J; Zornoza, J D; Zuñiga, J

    2017-04-12

    Despite dedicated research has been carried out to adequately map the distribution of the sperm whale in the Mediterranean Sea, unlike other regions of the world, the species population status is still presently uncertain. The analysis of two years of continuous acoustic data provided by the ANTARES neutrino telescope revealed the year-round presence of sperm whales in the Ligurian Sea, probably associated with the availability of cephalopods in the region. The presence of the Ligurian Sea sperm whales was demonstrated through the real-time analysis of audio data streamed from a cabled-to-shore deep-sea observatory that allowed the hourly tracking of their long-range echolocation behaviour on the Internet. Interestingly, the same acoustic analysis indicated that the occurrence of surface shipping noise would apparently not condition the foraging behaviour of the sperm whale in the area, since shipping noise was almost always present when sperm whales were acoustically detected. The continuous presence of the sperm whale in the region confirms the ecological value of the Ligurian sea and the importance of ANTARES to help monitoring its ecosystems.

  5. Sperm whale long-range echolocation sounds revealed by ANTARES, a deep-sea neutrino telescope

    NASA Astrophysics Data System (ADS)

    André, M.; Caballé, A.; van der Schaar, M.; Solsona, A.; Houégnigan, L.; Zaugg, S.; Sánchez, A. M.; Castell, J. V.; Solé, M.; Vila, F.; Djokic, D.; Adrián-Martínez, S.; Albert, A.; Anghinolfi, M.; Anton, G.; Ardid, M.; Aubert, J.-J.; Avgitas, T.; Baret, B.; Barrios-Martí, J.; Basa, S.; Bertin, V.; Biagi, S.; Bormuth, R.; Bouwhuis, M. C.; Bruijn, R.; Brunner, J.; Busto, J.; Capone, A.; Caramete, L.; Carr, J.; Celli, S.; Chiarusi, T.; Circella, M.; Coleiro, A.; Coniglione, R.; Costantini, H.; Coyle, P.; Creusot, A.; Deschamps, A.; de Bonis, G.; Distefano, C.; di Palma, I.; Donzaud, C.; Dornic, D.; Drouhin, D.; Eberl, T.; El Bojaddaini, I.; Elsässer, D.; Enzenhöfer, A.; Fehn, K.; Felis, I.; Fusco, L. A.; Galatà, S.; Gay, P.; Geißelsöder, S.; Geyer, K.; Giordano, V.; Gleixner, A.; Glotin, H.; Gracia-Ruiz, R.; Graf, K.; Hallmann, S.; van Haren, H.; Heijboer, A. J.; Hello, Y.; Hernandez-Rey, J. J.; Hößl, J.; Hofestädt, J.; Hugon, C.; Illuminati, G.; James, C. W.; de Jong, M.; Jongen, M.; Kadler, M.; Kalekin, O.; Katz, U.; Kießling, D.; Kouchner, A.; Kreter, M.; Kreykenbohm, I.; Kulikovskiy, V.; Lachaud, C.; Lahmann, R.; Lefèvre, D.; Leonora, E.; Loucatos, S.; Marcelin, M.; Margiotta, A.; Marinelli, A.; Martínez-Mora, J. A.; Mathieu, A.; Melis, K.; Michael, T.; Migliozzi, P.; Moussa, A.; Mueller, C.; Nezri, E.; Păvălaş, G. E.; Pellegrino, C.; Perrina, C.; Piattelli, P.; Popa, V.; Pradier, T.; Racca, C.; Riccobene, G.; Roensch, K.; Saldaña, M.; Samtleben, D. F. E.; Sanguineti, M.; Sapienza, P.; Schnabel, J.; Schüssler, F.; Seitz, T.; Sieger, C.; Spurio, M.; Stolarczyk, Th.; Sánchez-Losa, A.; Taiuti, M.; Trovato, A.; Tselengidou, M.; Turpin, D.; Tönnis, C.; Vallage, B.; Vallée, C.; van Elewyck, V.; Vivolo, D.; Wagner, S.; Wilms, J.; Zornoza, J. D.; Zuñiga, J.

    2017-04-01

    Despite dedicated research has been carried out to adequately map the distribution of the sperm whale in the Mediterranean Sea, unlike other regions of the world, the species population status is still presently uncertain. The analysis of two years of continuous acoustic data provided by the ANTARES neutrino telescope revealed the year-round presence of sperm whales in the Ligurian Sea, probably associated with the availability of cephalopods in the region. The presence of the Ligurian Sea sperm whales was demonstrated through the real-time analysis of audio data streamed from a cabled-to-shore deep-sea observatory that allowed the hourly tracking of their long-range echolocation behaviour on the Internet. Interestingly, the same acoustic analysis indicated that the occurrence of surface shipping noise would apparently not condition the foraging behaviour of the sperm whale in the area, since shipping noise was almost always present when sperm whales were acoustically detected. The continuous presence of the sperm whale in the region confirms the ecological value of the Ligurian sea and the importance of ANTARES to help monitoring its ecosystems.

  6. Long-range correlated dynamics in ultra-thin molecular glass films

    NASA Astrophysics Data System (ADS)

    Zhang, Yue; Glor, Ethan C.; Li, Mu; Liu, Tianyi; Wahid, Kareem; Zhang, William; Riggleman, Robert A.; Fakhraai, Zahra

    2016-09-01

    It has been previously shown that the free surface of molecular glasses has enhanced surface diffusion compared to the bulk. However, the degree by which the glass dynamics are affected by the free surface remains unexplored. Here, we measure enhanced dynamics in ultra-thin molecular glass films as a function of film thickness. We demonstrate that these films exhibit a sharp transition from glassy solid to liquid-like behavior when the thickness is reduced below 30 nm. This liquid-like behavior persists even at temperatures well below the glass transition temperature, Tg. The enhanced dynamics in these films can produce large scale morphological features during physical vapor deposition and lead to a dewetting instability in films held at temperatures as low as Tg - 35 K. The effective viscosity of these films are measured by monitoring the dewetting kinetics. These measurements combined with cooling-rate dependent Tg measurements show that the apparent activation barrier for rearrangement decreases sharply in films thinner than 30 nm. This sharp transition in the dynamics suggests that long-range correlated dynamics exists in these films such that the enhancement induced by the free surface can strongly affect the dynamics of the film over a length scale that is ten times larger than the size of the molecules.

  7. A Statistical Multimodel Ensemble Approach to Improving Long-Range Forecasting in Pakistan

    DTIC Science & Technology

    2012-03-01

    MULTIMODEL ENSEMBLE APPROACH TO IMPROVING LONG-RANGE FORECASTING IN PAKISTAN by Shane D. Gillies March 2012 Thesis Co-Advisors: Tom Murphree...DATES COVERED Master’s Thesis 4. TITLE AND SUBTITLE A Statistical Multimodel Ensemble Approach to Improving Long-Range Forecasting in Pakistan 5...was selected based on DoD and national intelligence priorities for long-range support. For this test case, the system uses 81 ensemble forecast

  8. Dissipative oscillations in spatially restricted ecosystems due to long range migration

    NASA Astrophysics Data System (ADS)

    Kouvaris, N.; Provata, A.

    2008-11-01

    An ecosystem containing three interacting species is studied using both Mean Field approach and Kinetic Monte Carlo simulations on a lattice substrate. The so called 3rd order LLV model involves birth, death and reaction processes with 3rd order nonlinearities and feedbacks. At the mean field level this system exhibits conservative oscillations; the analytic form of the constant of motion is presented. The stochastic simulations show that the density oscillations disappear for sufficiently large lattices, while they are present locally, on small lattice windows. Introduction of mixing via long range migration in the two reacting species changes this picture. For small migration rates p, the behavior remains as with p = 0 and the system is divided into local asynchronous oscillators. As p increases the system passes through a phase transition and exhibits a weak disorder limit cycle through a supercritical Hopf-like bifurcation. The amplitude of the limit cycle depends on the rate p, on the range of migration r and on the system kinetic rates k1, k2 and k3.

  9. Single-file diffusion of particles with long-range interactions: damping and finite-size effects.

    PubMed

    Delfau, Jean-Baptiste; Coste, Christophe; Saint Jean, Michel

    2011-07-01

    We study the single file diffusion of a cyclic chain of particles that cannot cross each other, in a thermal bath, with long-ranged interactions and arbitrary damping. We present simulations that exhibit new behaviors specifically associated with systems of small numbers of particles and with small damping. In order to understand those results, we present an original analysis based on the decomposition of the particles' motion in the normal modes of the chain. Our model explains all dynamic regimes observed in our simulations and provides convincing estimates of the crossover times between those regimes.

  10. Comment on the existence of a long range correlation in the geomagnetic disturbance storm time (Dst) index

    NASA Astrophysics Data System (ADS)

    Lacasa, Lucas

    2012-01-01

    Very recently (Banerjee et al. in Astrophys. Space, doi:10.1007/s10509-011-0836-1, 2011) the statistics of geomagnetic Disturbance storm (Dst) index have been addressed, and the conclusion from this analysis suggests that the underlying dynamical process can be modeled as a fractional Brownian motion with persistent long-range correlations. In this comment we expose several misconceptions and flaws in the statistical analysis of that work. On the basis of these arguments, the former conclusion should be revisited.

  11. Photon Devil’s staircase: photon long-range repulsive interaction in lattices of coupled resonators with Rydberg atoms

    PubMed Central

    Zhang, Yuanwei; Fan, Jingtao; Liang, J.-Q.; Ma, Jie; Chen, Gang; Jia, Suotang; Nori, Franco

    2015-01-01

    The realization of strong coherent interactions between individual photons is a long-standing goal in science and engineering. In this report, based on recent experimental setups, we derive a strong photon long-range repulsive interaction, by controlling the van der Waals repulsive force between Cesium Rydberg atoms located inside different cavities in extended Jaynes-Cummings-Hubbard lattices. We also find novel quantum phases induced by this photon long-range repulsive interaction. For example, without photon hopping, a photon Devil’s staircase, induced by the breaking of long-range translation symmetry, can emerge. If photon hopping occurs, we predict a photon-floating solid phase, due to the motion of particle- and hole-like defects. More importantly, for a large chemical potential in the resonant case, the photon hopping can be frozen even if the hopping term exists. We call this new phase the photon-frozen solid phase. In experiments, these predicted phases could be detected by measuring the number of polaritons via resonance fluorescence. PMID:26108705

  12. Robustness of Estimators of Long-range Dependence and Self-Similarity for Non-Gaussian Datasets.

    NASA Astrophysics Data System (ADS)

    Watkins, N. W.; Franzke, C. L. E.; Graves, T.; Gramacy, R. B.; Hughes, C.

    2012-04-01

    Evidence for long-range dependence and non-Gaussianity is ubiquitous in many natural systems like ecosystems, biological systems and climate. However, it is not always appreciated that both phenomena frequently occur together in natural systems, and that self-similarity of a system can result from the superposition of both phenomena. These features, which are common in complex systems, impact the attribution of trends and the occurrence and clustering of extremes. The risk assessment of systems posessing these properties will lead to different outcomes (e.g. return periods) than the more common assumption of independence of extremes. We discuss two paradigmatic models which can simultaneously account for long-range dependence and non-Gaussianity: Autoregressive Fractional Integrated Moving Average (ARFIMA) and Linear Fractional Stable Motion (LFSM). The statistical properties of estimators for long-range dependence and self-similarity are critically assessed as applied to these models. It is seen that the most popular estimators are not robust. In particular, they can be biased in the presence of important features of many natural systems like annual cycles, trends and multiplicative noise. [Related paper in press, Phil. Trans. Roy. Soc. A; preprint at arXiv:1101.5018

  13. Create Ownership in Your Long Range Plan with a Technology Audit.

    ERIC Educational Resources Information Center

    Biggs, Phil

    1988-01-01

    Discussion of group dynamics and long range planning focuses on a technology audit conducted to help determine a long range plan for computer use in the Rangley, Colorado, public schools. Planning strategies are explained, survey questions are presented, and the actual audit process and trends that emerged from it are described. (LRW)

  14. North Idaho College Long-Range Plan and Statement of Institutional Mission and Purpose.

    ERIC Educational Resources Information Center

    Cargol, Owen F.

    Based upon a planning project initiated at North Idaho College (NIC) in 1981 and approved by the Board of Trustees in 1982, this long-range plan states the mission of NIC and specifies goals and objectives to be attained in the next 3 years. First, introductory sections consider the qualities of a good long-range plan, address the responsibilities…

  15. 75 FR 1799 - Terminate Long Range Aids to Navigation (Loran-C) Signal

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-13

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF HOMELAND SECURITY Coast Guard Terminate Long Range Aids to Navigation (Loran-C) Signal AGENCY: U.S. Coast Guard, DHS... Register of January 7, 2010 (75 FR 998). The document announced termination of the Long Range Aids...

  16. 14 CFR 125.267 - Flight navigator and long-range navigation equipment.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Flight navigator and long-range navigation... Requirements § 125.267 Flight navigator and long-range navigation equipment. (a) No certificate holder may...-range means of navigation which enable a reliable determination to be made of the position of...

  17. College of DuPage Long Range Financial Plans, 1993 through 1997.

    ERIC Educational Resources Information Center

    College of DuPage, Glen Ellyn, IL.

    In 1992, a study was conducted to create a framework allowing administrators at the College of DuPage (CD) in Illinois to examine the long-range implications of financial decisions. The CD long-range financial plans consist of the following components: operating funds; construction funds; tax funds; auxiliary enterprise funds; and non-grant…

  18. 48 CFR 5.404 - Release of long-range acquisition estimates.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Release of long-range acquisition estimates. 5.404 Section 5.404 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION ACQUISITION PLANNING PUBLICIZING CONTRACT ACTIONS Release of Information 5.404 Release of long-range acquisition estimates. To assist...

  19. 48 CFR 5.404-2 - Announcements of long-range acquisition estimates.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Announcements of long-range acquisition estimates. 5.404-2 Section 5.404-2 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION ACQUISITION PLANNING PUBLICIZING CONTRACT ACTIONS Release of Information 5.404-2 Announcements of long-range acquisition estimates...

  20. 48 CFR 1305.404 - Release of long-range acquisition estimates.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Release of long-range acquisition estimates. 1305.404 Section 1305.404 Federal Acquisition Regulations System DEPARTMENT OF COMMERCE COMPETITION AND ACQUISITION PLANNING PUBLICIZING CONTRACT ACTIONS Release of Information 1305.404 Release of long-range acquisition estimates...

  1. 48 CFR 1405.404 - Release of long-range acquisition estimates.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Release of long-range acquisition estimates. 1405.404 Section 1405.404 Federal Acquisition Regulations System DEPARTMENT OF THE INTERIOR COMPETITION AND ACQUISITION PLANNING PUBLICIZING CONTRACT ACTIONS Release of Information 1405.404 Release of long-range acquisition...

  2. 48 CFR 605.404 - Release of long-range acquisition estimates.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 4 2010-10-01 2010-10-01 false Release of long-range acquisition estimates. 605.404 Section 605.404 Federal Acquisition Regulations System DEPARTMENT OF STATE COMPETITION AND ACQUISITION PLANNING PUBLICIZING CONTRACT ACTIONS Release of Information 605.404 Release of long-range acquisition estimates...

  3. 48 CFR 405.404 - Release of long-range acquisition estimates.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 4 2010-10-01 2010-10-01 false Release of long-range acquisition estimates. 405.404 Section 405.404 Federal Acquisition Regulations System DEPARTMENT OF AGRICULTURE COMPETITION AND ACQUISITION PLANNING PUBLICIZING CONTRACT ACTIONS Release of Information 405.404 Release of long-range acquisition estimates...

  4. College of DuPage Long Range Financial Plans, 1993 through 1997.

    ERIC Educational Resources Information Center

    College of DuPage, Glen Ellyn, IL.

    In 1992, a study was conducted to create a framework allowing administrators at the College of DuPage (CD) in Illinois to examine the long-range implications of financial decisions. The CD long-range financial plans consist of the following components: operating funds; construction funds; tax funds; auxiliary enterprise funds; and non-grant…

  5. The third stage of hospital long-range planning: the marketing approach.

    PubMed

    Rynne, T J

    1980-01-01

    Today most hospital administrators are convinced they should implement long-range planning. The marketing approach to long-range planning is an effective strategy that is consumer oriented. It starts the planning process with the consumer, letting the consumer's needs and wants guide the organization's planning.

  6. North Idaho College Long-Range Plan and Statement of Institutional Mission and Purpose.

    ERIC Educational Resources Information Center

    Cargol, Owen F.

    Based upon a planning project initiated at North Idaho College (NIC) in 1981 and approved by the Board of Trustees in 1982, this long-range plan states the mission of NIC and specifies goals and objectives to be attained in the next 3 years. First, introductory sections consider the qualities of a good long-range plan, address the responsibilities…

  7. Climate Analysis and Long Range Forecasting of Radar Performance in the Western North Pacific

    DTIC Science & Technology

    2009-06-01

    LONG RANGE FORECASTING OF RADAR PERFORMANCE IN THE WESTERN NORTH PACIFIC by David Ramsaur June 2009 Thesis Co-Advisors...2. REPORT DATE June 2009 3. REPORT TYPE AND DATES COVERED Master’s Thesis 4. TITLE AND SUBTITLE Climate Analysis and Long Range...degree of MASTER OF SCIENCE IN METEOROLOGY from the NAVAL POSTGRADUATE SCHOOL June 2009 Author: David C. Ramsaur

  8. 48 CFR 1305.404 - Release of long-range acquisition estimates.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 5 2013-10-01 2013-10-01 false Release of long-range acquisition estimates. 1305.404 Section 1305.404 Federal Acquisition Regulations System DEPARTMENT OF COMMERCE... long-range acquisition estimates....

  9. 48 CFR 405.404 - Release of long-range acquisition estimates.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 4 2011-10-01 2011-10-01 false Release of long-range acquisition estimates. 405.404 Section 405.404 Federal Acquisition Regulations System DEPARTMENT OF... Release of long-range acquisition estimates....

  10. 48 CFR 5.404-2 - Announcements of long-range acquisition estimates.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...-range acquisition estimates. 5.404-2 Section 5.404-2 Federal Acquisition Regulations System FEDERAL... Announcements of long-range acquisition estimates. Further publicizing, consistent with the needs of the individual case, may be accomplished by announcing through the GPE that long-range acquisition estimates...

  11. 48 CFR 1405.404 - Release of long-range acquisition estimates.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 5 2012-10-01 2012-10-01 false Release of long-range acquisition estimates. 1405.404 Section 1405.404 Federal Acquisition Regulations System DEPARTMENT OF THE... Release of long-range acquisition estimates....

  12. 48 CFR 1305.404 - Release of long-range acquisition estimates.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 5 2011-10-01 2011-10-01 false Release of long-range acquisition estimates. 1305.404 Section 1305.404 Federal Acquisition Regulations System DEPARTMENT OF COMMERCE... long-range acquisition estimates....

  13. 48 CFR 5.404-2 - Announcements of long-range acquisition estimates.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...-range acquisition estimates. 5.404-2 Section 5.404-2 Federal Acquisition Regulations System FEDERAL... Announcements of long-range acquisition estimates. Further publicizing, consistent with the needs of the individual case, may be accomplished by announcing through the GPE that long-range acquisition estimates...

  14. 48 CFR 1405.404 - Release of long-range acquisition estimates.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 5 2013-10-01 2013-10-01 false Release of long-range acquisition estimates. 1405.404 Section 1405.404 Federal Acquisition Regulations System DEPARTMENT OF THE... Release of long-range acquisition estimates....

  15. 48 CFR 605.404 - Release of long-range acquisition estimates.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 4 2012-10-01 2012-10-01 false Release of long-range acquisition estimates. 605.404 Section 605.404 Federal Acquisition Regulations System DEPARTMENT OF STATE... long-range acquisition estimates....

  16. 48 CFR 5.404 - Release of long-range acquisition estimates.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false Release of long-range...-range acquisition estimates. To assist industry planning and to locate additional sources of supply, it may be desirable to publicize estimates of unclassified long-range acquisition requirements....

  17. 48 CFR 1405.404 - Release of long-range acquisition estimates.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 5 2014-10-01 2014-10-01 false Release of long-range acquisition estimates. 1405.404 Section 1405.404 Federal Acquisition Regulations System DEPARTMENT OF THE... Release of long-range acquisition estimates....

  18. 48 CFR 405.404 - Release of long-range acquisition estimates.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 4 2014-10-01 2014-10-01 false Release of long-range acquisition estimates. 405.404 Section 405.404 Federal Acquisition Regulations System DEPARTMENT OF... Release of long-range acquisition estimates....

  19. 48 CFR 5.404 - Release of long-range acquisition estimates.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 1 2014-10-01 2014-10-01 false Release of long-range...-range acquisition estimates. To assist industry planning and to locate additional sources of supply, it may be desirable to publicize estimates of unclassified long-range acquisition requirements....

  20. 48 CFR 605.404 - Release of long-range acquisition estimates.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 4 2014-10-01 2014-10-01 false Release of long-range acquisition estimates. 605.404 Section 605.404 Federal Acquisition Regulations System DEPARTMENT OF STATE... long-range acquisition estimates....

  1. 48 CFR 1405.404 - Release of long-range acquisition estimates.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 5 2011-10-01 2011-10-01 false Release of long-range acquisition estimates. 1405.404 Section 1405.404 Federal Acquisition Regulations System DEPARTMENT OF THE... Release of long-range acquisition estimates....

  2. 48 CFR 405.404 - Release of long-range acquisition estimates.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 4 2013-10-01 2013-10-01 false Release of long-range acquisition estimates. 405.404 Section 405.404 Federal Acquisition Regulations System DEPARTMENT OF... Release of long-range acquisition estimates....

  3. 48 CFR 605.404 - Release of long-range acquisition estimates.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 4 2013-10-01 2013-10-01 false Release of long-range acquisition estimates. 605.404 Section 605.404 Federal Acquisition Regulations System DEPARTMENT OF STATE... long-range acquisition estimates....

  4. 48 CFR 605.404 - Release of long-range acquisition estimates.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 4 2011-10-01 2011-10-01 false Release of long-range acquisition estimates. 605.404 Section 605.404 Federal Acquisition Regulations System DEPARTMENT OF STATE... long-range acquisition estimates....

  5. 48 CFR 1305.404 - Release of long-range acquisition estimates.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 5 2014-10-01 2014-10-01 false Release of long-range acquisition estimates. 1305.404 Section 1305.404 Federal Acquisition Regulations System DEPARTMENT OF COMMERCE... long-range acquisition estimates....

  6. 48 CFR 5.404 - Release of long-range acquisition estimates.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 1 2013-10-01 2013-10-01 false Release of long-range...-range acquisition estimates. To assist industry planning and to locate additional sources of supply, it may be desirable to publicize estimates of unclassified long-range acquisition requirements....

  7. 48 CFR 1305.404 - Release of long-range acquisition estimates.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 5 2012-10-01 2012-10-01 false Release of long-range acquisition estimates. 1305.404 Section 1305.404 Federal Acquisition Regulations System DEPARTMENT OF COMMERCE... long-range acquisition estimates....

  8. 48 CFR 5.404-2 - Announcements of long-range acquisition estimates.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...-range acquisition estimates. 5.404-2 Section 5.404-2 Federal Acquisition Regulations System FEDERAL... Announcements of long-range acquisition estimates. Further publicizing, consistent with the needs of the individual case, may be accomplished by announcing through the GPE that long-range acquisition estimates...

  9. 48 CFR 405.404 - Release of long-range acquisition estimates.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 4 2012-10-01 2012-10-01 false Release of long-range acquisition estimates. 405.404 Section 405.404 Federal Acquisition Regulations System DEPARTMENT OF... Release of long-range acquisition estimates....

  10. 48 CFR 5.404 - Release of long-range acquisition estimates.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 1 2012-10-01 2012-10-01 false Release of long-range...-range acquisition estimates. To assist industry planning and to locate additional sources of supply, it may be desirable to publicize estimates of unclassified long-range acquisition requirements....

  11. 48 CFR 5.404-2 - Announcements of long-range acquisition estimates.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...-range acquisition estimates. 5.404-2 Section 5.404-2 Federal Acquisition Regulations System FEDERAL... Announcements of long-range acquisition estimates. Further publicizing, consistent with the needs of the individual case, may be accomplished by announcing through the GPE that long-range acquisition estimates...

  12. 23 CFR 450.214 - Development and content of the long-range statewide transportation plan.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... long-range statewide transportation plan should include capital, operations and management strategies... transportation system. The long-range statewide transportation plan may consider projects and strategies that... shall reference, summarize, or contain any applicable short-range planning studies; strategic planning...

  13. 23 CFR 450.214 - Development and content of the long-range statewide transportation plan.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... long-range statewide transportation plan should include capital, operations and management strategies... transportation system. The long-range statewide transportation plan may consider projects and strategies that... shall reference, summarize, or contain any applicable short-range planning studies; strategic planning...

  14. 23 CFR 450.214 - Development and content of the long-range statewide transportation plan.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...., transportation, safety, economic development, social and environmental effects, or energy) that were relevant to... 23 Highways 1 2011-04-01 2011-04-01 false Development and content of the long-range statewide... Programming § 450.214 Development and content of the long-range statewide transportation plan. (a) The State...

  15. 23 CFR 450.214 - Development and content of the long-range statewide transportation plan.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...., transportation, safety, economic development, social and environmental effects, or energy) that were relevant to... 23 Highways 1 2014-04-01 2014-04-01 false Development and content of the long-range statewide... Programming § 450.214 Development and content of the long-range statewide transportation plan. (a) The State...

  16. 23 CFR 450.214 - Development and content of the long-range statewide transportation plan.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...., transportation, safety, economic development, social and environmental effects, or energy) that were relevant to... 23 Highways 1 2013-04-01 2013-04-01 false Development and content of the long-range statewide... Programming § 450.214 Development and content of the long-range statewide transportation plan. (a) The State...

  17. Long Range Plan for Information Systems from the State Board of Education.

    ERIC Educational Resources Information Center

    Texas Education Agency, Austin.

    The Information Systems Long Range Plan specifically addresses Goal four of the Texas State Board of Education's (SBOE's) "Long-Range Plan for Public School Education" dealing with efficient management and organization of the educational system. To facilitate this goal, the SBOE in 1986 approved and directed the Texas Education Agency to…

  18. 14 CFR 125.267 - Flight navigator and long-range navigation equipment.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Flight navigator and long-range navigation... Requirements § 125.267 Flight navigator and long-range navigation equipment. (a) No certificate holder may...-range means of navigation which enable a reliable determination to be made of the position of the...

  19. 14 CFR 125.267 - Flight navigator and long-range navigation equipment.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Flight navigator and long-range navigation... Requirements § 125.267 Flight navigator and long-range navigation equipment. (a) No certificate holder may...-range means of navigation which enable a reliable determination to be made of the position of the...

  20. 14 CFR 125.267 - Flight navigator and long-range navigation equipment.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false Flight navigator and long-range navigation... Requirements § 125.267 Flight navigator and long-range navigation equipment. (a) No certificate holder may...-range means of navigation which enable a reliable determination to be made of the position of the...

  1. 14 CFR 125.267 - Flight navigator and long-range navigation equipment.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Flight navigator and long-range navigation... Requirements § 125.267 Flight navigator and long-range navigation equipment. (a) No certificate holder may...-range means of navigation which enable a reliable determination to be made of the position of the...

  2. Monte Carlo Study of One-Dimensional Ising Models with Long-Range Interactions

    NASA Astrophysics Data System (ADS)

    Tomita, Yusuke

    2009-01-01

    Recently, Fukui and Todo have proposed a new effective Monte Carlo algorithm for long-range interacting systems. Using the algorithm with the nonequilibrium relaxation method, we investigated long-range interacting one-dimensional Ising models both ferromagnetic and antiferromagnetic with the nearest-neighbor ferromagnetic interaction. For the antiferromagnetic model, we found the systems are paramagnetic at finite temperatures.

  3. 2. QUANTUM HALL EFFECT: Magnetocapacitance studies of two-dimensional electron systems with long-range potential fluctuations

    NASA Astrophysics Data System (ADS)

    Dorokhova, M. O.; Dorozhkin, S. I.

    2001-10-01

    We report on magnetocapacitance study of the quantum Hall effect (QHE) states. Capacitance minima width was found to be independent of magnetic field and to be the same for even, odd and fractional QHE states when measured as a function of the average electron density. This result indicates that the width of capacitance minima in the samples investigated are governed by long-range carrier density fluctuations. At low temperatures, the amplitudes of the minima decrease linearly with the temperature increase. All our experimental results for the integer QHE states are quantitatively explained by introducing unbroadened magnetic levels and dispersion of the electron density along the sample. The energy gaps at even filling factors obtained from fitting the experimental data are found to be close to the known cyclotron gaps. At odd fillings v = 1, 3, and 5, the energy gaps appear to be enhanced in comparison with the Zeeman splitting, with the enhancement decreasing with filling factor. The capacitance minima are argued to originate from the motion of incompressible regions along a sample caused by the gate voltage variation. We derive the condition for the appearance and motion of such regions for the case of gated samples with long-range fluctuations of density of charged donors. The appearance of narrow magnetocapacitance peaks when a dc current is passed through the sample is reported. We hypothesize that these peaks are due to the current percolation along incompressible regions.

  4. Sensitivity in the Correction of Long-Range Ground-Based Thermal Data.

    NASA Astrophysics Data System (ADS)

    Hancock, Anson; James, Mike; Ganci, Gaetana; Harris, Andrew

    2016-04-01

    Ground-based thermal remote sensing is a valuable tool for the study and monitoring of volcanoes and their hazards. However, permanent monitoring installations often require the camera to be positioned at relatively long ranges from the target (i.e. >1000 m). These types of long-range deployments have been seldom analysed quantitatively due primarily to factors such as atmospheric attenuation and across-image variations in the target path-length resulting in substantial uncertainty in the derived surface temperatures. Here we examine the sensitivity of measurements at three different apparent temperatures (400, 500 and 600 K) to uncertainty in the atmospheric conditions and type of path for the INGV-Catania (Etna, Sicily) permanently installed thermal camera. The camera is located at Mount Cagliato at an elevation of 1154 m asl and looks to the summit area at ˜3000 m asl, over a distance of ˜8.5 km. Analysis was carried out using MODTRAN to calculate atmospheric transmittance and upwelling radiance values for the different scenarios. We then calculated corrected surface temperatures by applying an atmospheric correction using two different temperature-to-radiance methods: a top-hat wavelength integrated based method supplied by FLIR Systems in their ThermaCam Researcher software and a mid-wavelength value method using the Planck equation. Results indicate that calculated surface temperatures between the two methods differ by as much as 382.5 K over a path-length of 8.5 km. Over path lengths between 1 and 8.5 km, changing the atmospheric temperature to 288.15 (15 oC), 293.15 (20 oC) and 298.15 K (25 oC) resulted in increases in calculated surface temperatures of 1.7-72.4 K using the FLIR top-hat method and 1.4-205.5 K using the mid-wavelength method. For relative humidities of 40, 50 and 60 %, increases in calculated surface temperatures of 1.0-58.7 K and 1.0-148.9 K using the FLIR top-hat and mid-wavelength methods, respectively. We also found that calculated

  5. Coordinated, long-range, solid substrate movement of the purple photosynthetic bacterium Rhodobacter capsulatus.

    PubMed

    Shelswell, Kristopher John; Beatty, J Thomas

    2011-05-04

    The long-range movement of Rhodobacter capsulatus cells in the glass-agar interstitial region of borosilicate Petri plates was found to be due to a subset of the cells inoculated into plates. The macroscopic appearance of plates indicated that a small group of cells moved in a coordinated manner to form a visible satellite cluster of cells. Satellite clusters were initially separated from the point of inoculation by the absence of visible cell density, but after 20 to 24 hours this space was colonized by cells apparently shed from a group of cells moving away from the point of inoculation. Cell movements consisted of flagellum-independent and flagellum-dependent motility contributions. Flagellum-independent movement occurred at an early stage, such that satellite clusters formed after 12 to 24 hours. Subsequently, after 24 to 32 hours, a flagellum-dependent dispersal of cells became visible, extending laterally outward from a line of flagellum-independent motility. These modes of taxis were found in several environmental isolates and in a variety of mutants, including a strain deficient in the production of the R. capsulatus acyl-homoserine lactone quorum-sensing signal. Although there was great variability in the direction of movement in illuminated plates, cells were predisposed to move toward broad spectrum white light. This predisposition was increased by the use of square plates, and a statistical analysis indicated that R. capsulatus is capable of genuine phototaxis. Therefore, the variability in the direction of cell movement was attributed to optical effects on light waves passing through the plate material and agar medium.

  6. Long-range propagation and associated variability of internal tides in the South China Sea

    NASA Astrophysics Data System (ADS)

    Xu, Zhenhua; Liu, Kun; Yin, Baoshu; Zhao, Zhongxiang; Wang, Yang; Li, Qun

    2016-11-01

    The variability of internal tides during their generation and long-range propagation in the South China Sea (SCS) is investigated by driving a high-resolution numerical model. The present study clarifies the notably different processes of generation, propagation, and dissipation between diurnal and semidiurnal internal tides. Internal tides in the SCS originate from multiple source sites, among which the Luzon Strait is dominant, and contributes approximately 90% and 74% of the baroclinic energy for M2 and K1, respectively. To the west of the Luzon Strait, local generation of K1 internal tides inside the SCS is more energetic than the M2 tides. Diurnal and semidiurnal internal tides from the Luzon Strait radiate into the SCS in a north-south asymmetry but with different patterns because of the complex two-ridge system. The tidal beams can travel across the deep basin and finally arrive at the Vietnam coast and Nansha Island more than 1000-1500 km away. During propagation, M2 internal tides maintain a southwestward direction, whereas K1 exhibit complicated wave fields because of the superposition of waves from local sources and island scattering effects. After significant dissipation within the Luzon Strait, the remaining energy travels into the SCS and reduces by more than 90% over a distance of ˜1000 km. Inside the SCS, the K1 internal tides with long crests and flat beam angles are more influenced by seafloor topographical features and thus undergo apparent dissipation along the entire path, whereas the prominent dissipation of M2 internal tides only occurs after their arrival at Zhongsha Island.

  7. Long-range transport of hydrothermal iron facilitated by dissolved-particulate exchange

    NASA Astrophysics Data System (ADS)

    Forsch, K.; Fitzsimmons, J. N.; German, C. R.; Sherrell, R. M.

    2016-02-01

    Deep-sea hydrothermal venting has a strong impact on ocean chemistry close to vent sites; however, effects of these systems on basin- and global-scale ocean biogeochemistry have only started to be observed and modeled. The U.S. GEOTRACES Eastern Pacific Zonal Transect investigated potential long-range hydrothermal influences by sampling the length of the 15°S Southern East Pacific Rise (EPR) plume as far as 150°W, following a plume extending >4000 km from the EPR based on He-3 distributions and the distribution of metal-rich sediments. It was recently reported that dissolved iron (dFe) in this plume is apparently transported conservatively >4000km across the South Pacific, with potential for ultimate upwelling in the Fe-limited Southern Ocean. The mechanism by which this dissolved Fe is maintained in solution, however, remains a topic of active debate. Here we show that hydrothermal Fe in the particulate phase, which exceeds the dissolved Fe concentration over much of the plume, is also enriched relative to background across the same 4300 km transect but that maximum pFe concentrations both decrease non-conservatively and deepen progressively relative to dissolved 3He anomalies across the section. Stokesian settling would require an FeOOH particle size of 0.5 µm in order to explain the 500 m "sag" observed over the 50 y of plume transport. A striking feature of the dissolved Fe plume is that it, too, descends in the water column over the length of the plume, following the particulate Fe plume. This suggests an active exchange between dissolved and particulate Fe species on timescales that are short relative to plume advection across the South Pacific. Thus, the large-scale distribution of particulate Fe appears to influence the preservation of the dFe pool, suggesting that the basin-scale impact of hydrothermal vent systems needs to consider both Fe phases and their long-term interactions.

  8. Gaussian approach for phase ordering in nonconserved scalar systems with long-range interactions

    NASA Astrophysics Data System (ADS)

    Filipe, J. A. N.; Bray, A. J.

    1995-01-01

    We have applied the Gaussian auxiliary field method to a nonconserved scalar system with attractive long-range interactions, falling off with distance as 1/rd+σ, where d is the spatial dimension and 0<σ<2. This study provides a test bed for the approach and shows some of the difficulties encountered in constructing a closed equation for the pair correlation function. For the relation φ=φ(m) between the order parameter φ and the auxiliary field m, the usual choice of the equilibrium interfacial profile is made. The equation obtained for the equal-time two-point correlation function is studied in the limiting cases of small and large values of the scaling variable. A Porod regime at short distance and an asymptotic power-law decay at large distance are obtained. The theory is not, however, consistent with the expected growth law and attempts to retrieve the correct growth lead to inconsistencies. These results indicate a failure of the Gaussian assumption for this system, when used in the context of the bulk dynamics. This statement holds at least within the present form of the mapping φ=φ(m), which appears to be the most natural choice, as well as the one consistent with the emergence of the Porod regime. By contrast, Ohta and Hayakawa have recenlty succeeded in implementing a Gaussian approach based on the interfacial dynamics of this system [Physica A 204, 482 (1994)]. This clearly suggests that, beyond the simplicity of short-range ``model A'' dynamics, a Gaussian approach can only capture the essential physical features if the crucial role of wall motion in domain growth is explicitly considered.

  9. Nonlinear effects in propagation of long-range surface plasmon polaritons in gold strip waveguides

    NASA Astrophysics Data System (ADS)

    Lysenko, Oleg; Bache, Morten; Malureanu, Radu; Lavrinenko, Andrei

    2016-04-01

    This paper is devoted to experimental and theoretical studies of nonlinear propagation of a long-range surface plasmon polariton (LRSPP) in gold strip waveguides. The plasmonic waveguides are fabricated in house, and contain a gold layer, tantalum pentoxide adhesion layers, and silicon dioxide cladding. The optical characterization was performed using a high power picosecond laser at 1064 nm. The experiments reveal two nonlinear optical effects: nonlinear power transmission and spectral broadening of the LRSPP mode in the waveguides. Both nonlinear optical effects depend on the gold layer thickness. The theoretical model of these effects is based on the third-order susceptibility of the constituent materials. The linear and nonlinear parameters of the LRSPP mode are obtained, and the nonlinear Schrödinger equation is solved. The dispersion length is much larger than the waveguides length, and the chromatic dispersion does not affect the propagation of the plasmonic mode. We find that the third-order susceptibility of the gold layer has a dominant contribution to the effective third-order susceptibility of the LRSPP mode. The real part of the effective third-order susceptibility leads to the observed spectral broadening through the self-phase modulation effect, and its imaginary part determines the nonlinear absorption parameter and leads to the observed nonlinear power transmission. The experimental values of the third-order susceptibility of the gold layers are obtained. They indicate an effective enhancement of the third-order susceptibility for the gold layers, comparing to the bulk gold values. This enhancement is explained in terms of the change of the electrons motion.

  10. Long-range non-contact imaging photoplethysmography: cardiac pulse wave sensing at a distance

    NASA Astrophysics Data System (ADS)

    Blackford, Ethan B.; Estepp, Justin R.; Piasecki, Alyssa M.; Bowers, Margaret A.; Klosterman, Samantha L.

    2016-03-01

    Non-contact, imaging photoplethysmography uses photo-optical sensors to measure variations in light absorption, caused by blood volume pulsations, to assess cardiopulmonary parameters including pulse rate, pulse rate variability, and respiration rate. Recently, researchers have studied the applications and methodology of imaging photoplethysmography. Basic research has examined some of the variables affecting data quality and accuracy of imaging photoplethysmography including signal processing, imager parameters (e.g. frame rate and resolution), lighting conditions, subject motion, and subject skin tone. This technology may be beneficial for long term or continuous monitoring where contact measurements may be harmful (e.g. skin sensitivities) or where imperceptible or unobtrusive measurements are desirable. Using previously validated signal processing methods, we examined the effects of imager-to-subject distance on one-minute, windowed estimates of pulse rate. High-resolution video of 22, stationary participants was collected using an enthusiast-grade, mirrorless, digital camera equipped with a fully-manual, super-telephoto lens at distances of 25, 50, and 100 meters with simultaneous contact measurements of electrocardiography, and fingertip photoplethysmography. By comparison, previous studies have usually been conducted with imager-to-subject distances of up to only a few meters. Mean absolute error for one-minute, windowed, pulse rate estimates (compared to those derived from gold-standard electrocardiography) were 2.0, 4.1, and 10.9 beats per minute at distances of 25, 50, and 100 meters, respectively. Long-range imaging presents several unique challenges among which include decreased, observed light reflectance and smaller regions of interest. Nevertheless, these results demonstrate that accurate pulse rate measurements can be obtained from over long imager-to-participant distances given these constraints.

  11. Long Range Correlation of Hydrophilicity and Flexibility Along the Hemoglobin Chain

    SciTech Connect

    Craciun, D.; Isvoran, A.; Avram, N. M.

    2010-08-04

    Within this study, we reveal the long range correlation concerning hydrophilicity and flexibility along sequences of hemoglobins belonging to different organisms and we compare them with the long range correlations properties obtained for other protein families. For all hemoglobins considered, we investigate two discrete spatial series: the hydrophilicity and flexibility respectively. We apply the nonlinear analysis methods to analyze the two spatial series by calculating the spectral coefficient {beta}, the scaling exponent {alpha} and Hurst exponent H. The obtained values for the mentioned coefficients suggest long range correlation within the analyzed sequences of hemoglobins in good agreement with those obtained for the calcium binding proteins and hydrolases.

  12. Long range intermolecular interactions between the alkali diatomics Na2, K2, and NaK

    NASA Astrophysics Data System (ADS)

    Zemke, Warren T.; Byrd, Jason N.; Michels, H. Harvey; Montgomery, John A.; Stwalley, William C.

    2010-06-01

    Long range interactions between the ground state alkali diatomics Na2-Na2, K2-K2, Na2-K2, and NaK-NaK are examined. Interaction energies are first determined from ab initio calculations at the coupled-cluster with singles, doubles, and perturbative triples [CCSD(T)] level of theory, including counterpoise corrections. Long range energies calculated from diatomic molecular properties (polarizabilities and dipole and quadrupole moments) are then compared with the ab initio energies. A simple asymptotic model potential ELR=Eelec+Edisp+Eind is shown to accurately represent the intermolecular interactions for these systems at long range.

  13. Long range intermolecular interactions between the alkali diatomics Na(2), K(2), and NaK.

    PubMed

    Zemke, Warren T; Byrd, Jason N; Michels, H Harvey; Montgomery, John A; Stwalley, William C

    2010-06-28

    Long range interactions between the ground state alkali diatomics Na(2)-Na(2), K(2)-K(2), Na(2)-K(2), and NaK-NaK are examined. Interaction energies are first determined from ab initio calculations at the coupled-cluster with singles, doubles, and perturbative triples [CCSD(T)] level of theory, including counterpoise corrections. Long range energies calculated from diatomic molecular properties (polarizabilities and dipole and quadrupole moments) are then compared with the ab initio energies. A simple asymptotic model potential E(LR)=E(elec)+E(disp)+E(ind) is shown to accurately represent the intermolecular interactions for these systems at long range.

  14. Research on risk long range identification for vessel traffic dynamic system

    NASA Astrophysics Data System (ADS)

    Qi, Ji; Guo, Ruijuan; Wang, Xiaoyu; Zhang, Hainan

    2017-09-01

    Vessel Long-range identification and tracking system has already been widely installed and applied in vessel. In this paper AIS system, vessel reporting system and LRIT in China are compared and analyzed based on the coverage area, confidentiality and accuracy of the LRIT information. Vessel Long-range identification and tracking model is established through a combination of AIS with LRIT system, which is applied to the research of vessel traffic dynamic system risk long range identification. Finally, the application of LRIT in the maritime field is discussed.

  15. Ising-model description of long-range correlations in DNA sequences.

    PubMed

    Colliva, A; Pellegrini, R; Testori, A; Caselle, M

    2015-05-01

    We model long-range correlations of nucleotides in the human DNA sequence using the long-range one-dimensional (1D) Ising model. We show that, for distances between 10(3) and 10(6) bp, the correlations show a universal behavior and may be described by the non-mean-field limit of the long-range 1D Ising model. This allows us to make some testable hypothesis on the nature of the interaction between distant portions of the DNA chain which led to the DNA structure that we observe today in higher eukaryotes.

  16. Ising-model description of long-range correlations in DNA sequences

    NASA Astrophysics Data System (ADS)

    Colliva, A.; Pellegrini, R.; Testori, A.; Caselle, M.

    2015-05-01

    We model long-range correlations of nucleotides in the human DNA sequence using the long-range one-dimensional (1D) Ising model. We show that, for distances between 103 and 106 bp, the correlations show a universal behavior and may be described by the non-mean-field limit of the long-range 1D Ising model. This allows us to make some testable hypothesis on the nature of the interaction between distant portions of the DNA chain which led to the DNA structure that we observe today in higher eukaryotes.

  17. Relationships Between Long-Range Lightning Networks and TRMM/LIS Observations

    NASA Technical Reports Server (NTRS)

    Rudlosky, Scott D.; Holzworth, Robert H.; Carey, Lawrence D.; Schultz, Chris J.; Bateman, Monte; Cummins, Kenneth L.; Cummins, Kenneth L.; Blakeslee, Richard J.; Goodman, Steven J.

    2012-01-01

    Recent advances in long-range lightning detection technologies have improved our understanding of thunderstorm evolution in the data sparse oceanic regions. Although the expansion and improvement of long-range lightning datasets have increased their applicability, these applications (e.g., data assimilation, atmospheric chemistry, and aviation weather hazards) require knowledge of the network detection capabilities. The present study intercompares long-range lightning data with observations from the Lightning Imaging Sensor (LIS) aboard the Tropical Rainfall Measurement Mission (TRMM) satellite. The study examines network detection efficiency and location accuracy relative to LIS observations, describes spatial variability in these performance metrics, and documents the characteristics of LIS flashes that are detected by the long-range networks. Improved knowledge of relationships between these datasets will allow researchers, algorithm developers, and operational users to better prepare for the spatial and temporal coverage of the upcoming GOES-R Geostationary Lightning Mapper (GLM).

  18. Long-range excitation energy transfer in Langmuir-Blodgett multilayer systems

    NASA Astrophysics Data System (ADS)

    Draxler, Sonja; Lippitsch, Max E.; Aussenegg, Franz R.

    1989-07-01

    In Langmuir-Blodgett films containing organic dyes, efficient energy transfer over distances exceeding 100 nm is observed. This exceptionally long-range transfer is interpreted as due to special mutual orientation of the dye molecules.

  19. 25 CFR 170.410 - What is the purpose of tribal long-range transportation planning?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... WATER INDIAN RESERVATION ROADS PROGRAM Planning, Design, and Construction of Indian Reservation Roads..., and health and social needs. (b) The time horizon for long-range transportation planning should be...

  20. Long-Range Cortical Dynamics: A Perspective from the Mouse Sensorimotor Whisker System.

    PubMed

    Ni, Jianguang; Chen, Jerry L

    2017-09-16

    In the mammalian neocortex, the capacity to dynamically route and coordinate the exchange of information between areas is a critical feature of cognitive function, enabling processes such as higher-level sensory processing and sensorimotor integration. Despite the importance attributed to long-range connections between cortical areas, their exact operations and role in cortical function remain an open question. In recent years, progress has been made in understanding long-range cortical circuits through work focused on the mouse sensorimotor whisker system. In this review, we examine recent studies dissecting long-range circuits involved in whisker sensorimotor processing as an entry point for understanding the rules that govern long-range cortical circuit function. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  1. van der Waals forces in density functional theory: Perturbational long-range electron-interaction corrections

    SciTech Connect

    Angyan, Janos G.; Gerber, Iann C.; Savin, Andreas; Toulouse, Julien

    2005-07-15

    Long-range exchange and correlation effects, responsible for the failure of currently used approximate density functionals in describing van der Waals forces, are taken into account explicitly after a separation of the electron-electron interaction in the Hamiltonian into short- and long-range components. We propose a 'range-separated hybrid' functional based on a local density approximation for the short-range exchange-correlation energy, combined with a long-range exact exchange energy. Long-range correlation effects are added by a second-order perturbational treatment. The resulting scheme is general and is particularly well adapted to describe van der Waals complexes, such as rare gas dimers.

  2. Planelike Interfaces in Long-Range Ising Models and Connections with Nonlocal Minimal Surfaces

    NASA Astrophysics Data System (ADS)

    Cozzi, Matteo; Dipierro, Serena; Valdinoci, Enrico

    2017-06-01

    This paper contains three types of results: the construction of ground state solutions for a long-range Ising model whose interfaces stay at a bounded distance from any given hyperplane,

  3. Long-range excitons in conjugated polymers with ring torsions: poly( para-phenylene) and polyaniline

    NASA Astrophysics Data System (ADS)

    Harigaya, Kikuo

    1998-08-01

    Ring torsion effects on the optical excitation properties of poly( para-phenylene) (PPP) and polyaniline (PAN) are investigated by extending the Shimoi-Abe model (Shimoi Y and Abe S 1996 Synth. Met. 78 219). The model is solved using the intermediate-exciton formalism. Long-range excitons are characterized, and the long-range component of the oscillator strengths is calculated. We find that ring torsions affect the long-range excitons in PAN more readily than those in PPP, due to the larger torsion angle of PAN and the large number of bonds whose hopping integrals are modulated by torsions. Next, ring torsional disorder effects simulated by the Gaussian distribution function are analysed. The long-range component of the total oscillator strengths after sample averaging is nearly independent of the disorder strength in the PPP case, while that in the PAN case decreases readily as the disorder becomes stronger.

  4. Modeling of Long-Range Atmospheric Lasercom Links Between Static and Mobile Platforms

    SciTech Connect

    Scharlemann, E T; Breitfeller, E F; Henderson, J R; Kallman, J S; Morris, J R; Ruggiero, A J

    2003-07-29

    We describe modeling and simulation of long-range terrestrial laser communications links between static and mobile platforms. Atmospheric turbulence modeling, along with pointing, tracking and acquisition models are combined to provide an overall capability to estimate communications link performance.

  5. 25 CFR 170.412 - How is the tribal IRR long-range transportation plan developed and approved?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false How is the tribal IRR long-range transportation plan... Reservation Roads Program Facilities Long-Range Transportation Planning § 170.412 How is the tribal IRR long-range transportation plan developed and approved? (a) The tribal IRR long-range transportation plan...

  6. 25 CFR 170.412 - How is the tribal IRR long-range transportation plan developed and approved?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 1 2013-04-01 2013-04-01 false How is the tribal IRR long-range transportation plan... Reservation Roads Program Facilities Long-Range Transportation Planning § 170.412 How is the tribal IRR long-range transportation plan developed and approved? (a) The tribal IRR long-range transportation plan...

  7. 25 CFR 170.414 - How is the tribal long-range transportation plan used and updated?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 25 Indians 1 2014-04-01 2014-04-01 false How is the tribal long-range transportation plan used and... Program Facilities Long-Range Transportation Planning § 170.414 How is the tribal long-range transportation plan used and updated? The tribal government uses its IRR long-range transportation plan in...

  8. 25 CFR 170.414 - How is the tribal long-range transportation plan used and updated?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 1 2013-04-01 2013-04-01 false How is the tribal long-range transportation plan used and... Program Facilities Long-Range Transportation Planning § 170.414 How is the tribal long-range transportation plan used and updated? The tribal government uses its IRR long-range transportation plan in...

  9. 25 CFR 170.412 - How is the tribal IRR long-range transportation plan developed and approved?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 25 Indians 1 2014-04-01 2014-04-01 false How is the tribal IRR long-range transportation plan... Reservation Roads Program Facilities Long-Range Transportation Planning § 170.412 How is the tribal IRR long-range transportation plan developed and approved? (a) The tribal IRR long-range transportation plan...

  10. Fluctuations and Universality in a Catalysis Model with Long-range Reactivity

    NASA Astrophysics Data System (ADS)

    Chan, Chor-Hoi; Rikvold, Per Arne

    The critical properties of the Ziff-Gulari-Barshad (ZGB) model with the addition of long-range reactivity [C. H. Chan and P. A. Rikvold, Phys. Rev. E 91, 012103 (2015)] are further investigated. The scaling behaviors of the order parameter, susceptibility, and correlation length provide additional evidence that the universality class of the ZGB system changes from the two-dimensional Ising class to the mean-field class with the addition of even a weak long-range reactivity mechanism.

  11. Damage assessment of long-range rocket system by electromagnetic pulse weapon

    NASA Astrophysics Data System (ADS)

    Cao, Lingyu; Liu, Guoqing; Li, Jinming

    2017-08-01

    This paper analyzes the damage mechanism and characteristics of electromagnetic pulse weapon, establishes the index system of survivability of long-range rocket launcher system, and uses AHP method to establish the combat effectiveness model of long-range rocket missile system. According to the damage mechanism and characteristics of electromagnetic pulse weapon, the damage effect of the remote rocket system is established by using the exponential method to realize the damage efficiency of the remote rocket system.

  12. Surface Roughness Measurements Utilizing Long-Range Surface-Plasma Waves

    DTIC Science & Technology

    1984-11-01

    Surface Roughness Measurements ... ______ 12. PERSONAL AuJTMORJSI Dror Sarid 13&~ TvrP OP REPORT 13b TIME COVERED 114 OATE OF REPORT Y,. Mo.. Day, 15...Investigator: Dror Sarid During the contract period we (1) performed an experiment to measure the dispersion of the long-range surf ace-plasmon... Dror Sarid , Robert. T. Deck. Alan. Z. Craig. Robert. K. Itickersell, Ralph S. Jameson. and Joseph J. Fasano. -Optical Field Enhancement by Long-Range

  13. Absence of Long-Range Chemical Ordering in Equimolar FeCoCrNi

    DTIC Science & Technology

    2012-06-20

    high - entropy alloys ," where the name is derived from the high configurational entropy of mixing for a random solid solution...heat treatment lacks long- range chemical order.© 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4730327] High - entropy alloys (HEAs...phase and a Cr-rich disordered phase. For high - entropy alloys that do exhibit long-range chemical ordering tendencies, such as the alloy of this

  14. FAST TRACK COMMUNICATION: Current fluctuations in stochastic systems with long-range memory

    NASA Astrophysics Data System (ADS)

    Harris, R. J.; Touchette, H.

    2009-08-01

    We propose a method to calculate the large deviations of current fluctuations in a class of stochastic particle systems with history-dependent rates. Long-range temporal correlations are seen to alter the speed of the large deviation function in analogy with long-range spatial correlations in equilibrium systems. We give some illuminating examples and discuss the applicability of the Gallavotti-Cohen fluctuation theorem.

  15. Statistical mechanics in biology: how ubiquitous are long-range correlations?

    NASA Technical Reports Server (NTRS)

    Stanley, H. E.; Buldyrev, S. V.; Goldberger, A. L.; Goldberger, Z. D.; Havlin, S.; Mantegna, R. N.; Ossadnik, S. M.; Peng, C. K.; Simons, M.

    1994-01-01

    The purpose of this opening talk is to describe examples of recent progress in applying statistical mechanics to biological systems. We first briefly review several biological systems, and then focus on the fractal features characterized by the long-range correlations found recently in DNA sequences containing non-coding material. We discuss the evidence supporting the finding that for sequences containing only coding regions, there are no long-range correlations. We also discuss the recent finding that the exponent alpha characterizing the long-range correlations increases with evolution, and we discuss two related models, the insertion model and the insertion-deletion model, that may account for the presence of long-range correlations. Finally, we summarize the analysis of long-term data on human heartbeats (up to 10(4) heart beats) that supports the possibility that the successive increments in the cardiac beat-to-beat intervals of healthy subjects display scale-invariant, long-range "anti-correlations" (a tendency to beat faster is balanced by a tendency to beat slower later on). In contrast, for a group of subjects with severe heart disease, long-range correlations vanish. This finding suggests that the classical theory of homeostasis, according to which stable physiological processes seek to maintain "constancy," should be extended to account for this type of dynamical, far from equilibrium, behavior.

  16. Statistical mechanics in biology: how ubiquitous are long-range correlations?

    NASA Technical Reports Server (NTRS)

    Stanley, H. E.; Buldyrev, S. V.; Goldberger, A. L.; Goldberger, Z. D.; Havlin, S.; Mantegna, R. N.; Ossadnik, S. M.; Peng, C. K.; Simons, M.

    1994-01-01

    The purpose of this opening talk is to describe examples of recent progress in applying statistical mechanics to biological systems. We first briefly review several biological systems, and then focus on the fractal features characterized by the long-range correlations found recently in DNA sequences containing non-coding material. We discuss the evidence supporting the finding that for sequences containing only coding regions, there are no long-range correlations. We also discuss the recent finding that the exponent alpha characterizing the long-range correlations increases with evolution, and we discuss two related models, the insertion model and the insertion-deletion model, that may account for the presence of long-range correlations. Finally, we summarize the analysis of long-term data on human heartbeats (up to 10(4) heart beats) that supports the possibility that the successive increments in the cardiac beat-to-beat intervals of healthy subjects display scale-invariant, long-range "anti-correlations" (a tendency to beat faster is balanced by a tendency to beat slower later on). In contrast, for a group of subjects with severe heart disease, long-range correlations vanish. This finding suggests that the classical theory of homeostasis, according to which stable physiological processes seek to maintain "constancy," should be extended to account for this type of dynamical, far from equilibrium, behavior.

  17. Statistical mechanics in biology: how ubiquitous are long-range correlations?

    NASA Astrophysics Data System (ADS)

    Stanley, H. E.; Buldyrev, S. V.; Goldberger, A. L.; Goldberger, Z. D.; Havlin, S.; Mantegna, R. N.; Ossadnik, S. M.; Peng, C.-K.; Simons, M.

    1994-04-01

    The purpose of this opening talk is to describe examples of recent progress in applying statistical mechanics to biological systems. We first briefly review several biological systems, and then focus on the fractal features characterized by the long-range correlations found recently in DNA sequences containing non-coding material. We discuss the evidence supporting the finding that for sequences containing only coding regions, there are no long-range correlations. We also discuss the recent finding that the exponent α characterizing the long-range correlations increases with evolution, and we discuss two related models, the insertion model and the insertion-deletion model, that may account for the presence of long-range correlations. Finally, we summarize the analysis of long-term data on human heartbeats (up to 10 4 heart beats) that supports the possibility that the successive increments in the cardiac beat-to-beat intervals of healthy subjects display scale-invariant, long-range “anti-correlations” (a tendency to beat faster is balanced by a tendency to beat slower later on). In contrast, for a group of subjects with severe heart disease, long-range correlations vanish. This finding suggests that the classical theory of homeostasis, according to which stable physiological processes seek to maintain “constancy,” should be extended to account for this type of dynamical, far from equilibrium, behavior.

  18. Shielding and localization in the presence of long-range hopping

    NASA Astrophysics Data System (ADS)

    Celardo, G. L.; Kaiser, R.; Borgonovi, F.

    2016-10-01

    We investigate a paradigmatic model for quantum transport with both nearest-neighbor and infinite-range hopping coupling (independent of the position). Due to long-range homogeneous hopping, a gap between the ground state and the excited states can be induced, which is mathematically equivalent to the superconducting gap. In the gapped regime, the dynamics within the excited-state subspace is shielded from long-range hopping, namely it occurs as if long-range hopping would be absent. This is a cooperative phenomenon since shielding is effective over a time scale that diverges with the system size. We named this effect cooperative shielding. We also discuss the consequences of our findings on Anderson localization. Long-range hopping is usually thought to destroy localization due to the fact that it induces an infinite number of resonances. Contrary to this common lore we show that the excited states display strong localized features when shielding is effective even in the regime of strong long-range coupling. A brief discussion on the extension of our results to generic power-law decaying long-range hopping is also given. Our preliminary results confirm that the effects found for the infinite-range case are generic.

  19. Long-Range Correlations in Stride Intervals May Emerge from Non-Chaotic Walking Dynamics

    PubMed Central

    Ahn, Jooeun; Hogan, Neville

    2013-01-01

    Stride intervals of normal human walking exhibit long-range temporal correlations. Similar to the fractal-like behaviors observed in brain and heart activity, long-range correlations in walking have commonly been interpreted to result from chaotic dynamics and be a signature of health. Several mathematical models have reproduced this behavior by assuming a dominant role of neural central pattern generators (CPGs) and/or nonlinear biomechanics to evoke chaos. In this study, we show that a simple walking model without a CPG or biomechanics capable of chaos can reproduce long-range correlations. Stride intervals of the model revealed long-range correlations observed in human walking when the model had moderate orbital stability, which enabled the current stride to affect a future stride even after many steps. This provides a clear counterexample to the common hypothesis that a CPG and/or chaotic dynamics is required to explain the long-range correlations in healthy human walking. Instead, our results suggest that the long-range correlation may result from a combination of noise that is ubiquitous in biological systems and orbital stability that is essential in general rhythmic movements. PMID:24086274

  20. A Multi-Sensor Fusion MAV State Estimation from Long-Range Stereo, IMU, GPS and Barometric Sensors

    PubMed Central

    Song, Yu; Nuske, Stephen; Scherer, Sebastian

    2016-01-01

    State estimation is the most critical capability for MAV (Micro-Aerial Vehicle) localization, autonomous obstacle avoidance, robust flight control and 3D environmental mapping. There are three main challenges for MAV state estimation: (1) it can deal with aggressive 6 DOF (Degree Of Freedom) motion; (2) it should be robust to intermittent GPS (Global Positioning System) (even GPS-denied) situations; (3) it should work well both for low- and high-altitude flight. In this paper, we present a state estimation technique by fusing long-range stereo visual odometry, GPS, barometric and IMU (Inertial Measurement Unit) measurements. The new estimation system has two main parts, a stochastic cloning EKF (Extended Kalman Filter) estimator that loosely fuses both absolute state measurements (GPS, barometer) and the relative state measurements (IMU, visual odometry), and is derived and discussed in detail. A long-range stereo visual odometry is proposed for high-altitude MAV odometry calculation by using both multi-view stereo triangulation and a multi-view stereo inverse depth filter. The odometry takes the EKF information (IMU integral) for robust camera pose tracking and image feature matching, and the stereo odometry output serves as the relative measurements for the update of the state estimation. Experimental results on a benchmark dataset and our real flight dataset show the effectiveness of the proposed state estimation system, especially for the aggressive, intermittent GPS and high-altitude MAV flight. PMID:28025524