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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. 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.

  4. 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}.

  5. 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.

  6. 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.

  7. 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

  8. Global Low Frequency Protein Motions in Long-Range Allosteric Signaling

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

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

  9. 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.

  10. 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.

  11. 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

  12. 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.

  13. 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…

  14. 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.

  15. 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.

  16. 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.

  17. 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

  18. 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.…

  19. 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

  20. 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

  1. Design improvement of the three-beam detector towards a precise long-range 6-degree of freedom motion sensor system

    SciTech Connect

    Kim, Young-Keun; Kim, Kyung-Soo Kim, Soohyun; Jang, In Gwun

    2014-01-15

    This paper presents performance enhancement of the three beam detector through design improvement based on the error analysis. The three-beam detector is a novel sensor system that measures six motions (i.e., 3 translations and 3 rotations) of a remote object with high accuracy by implementing three laser distance sensors and a vision sensor. In this paper, finite element analysis and parameter analysis are applied to the three-beam detector to analyze its structural frames and sensor configuration, respectively, in terms of sensing error. By virtue of such a systematic, quantitative error analysis, this research has successfully improved the performance of the three-beam detector and thoroughly validated through field tests that it can detect the 6-degree of freedom motions of a remote target at 30 m with an accuracy of 1.51 mm and 0.18° and precision of 0.38 mm and 0.13°.

  2. 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.

  3. 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.

  4. 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

  5. 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…

  6. 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

  7. 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.

  8. 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.

  9. 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…

  10. 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.

  11. 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.

  12. 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.

  13. 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

  14. 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.

  15. 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

  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. 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.

  19. 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).

  20. 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

  1. 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

  2. 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

  3. 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…

  4. 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…

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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).

  10. 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.

  11. 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.

  12. 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

  13. 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.

  14. 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.

  15. 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…

  16. 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)

  17. 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)

  18. 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.

  19. 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…

  20. 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

  1. 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.

  2. 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.

  3. 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.

  4. 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

  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. 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.

  7. 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.

  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 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.

  10. 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.

  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. 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

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. 77 FR 13683 - Alaska Federal Lands Long Range Transportation Plan

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-07

    ... Federal Highway Administration Alaska Federal Lands Long Range Transportation Plan AGENCY: Federal Highway..., announced the availability of the draft Alaska Federal Lands Long Range Transportation Plans (LRTP) for... Alaska Federal Lands draft Long Range Transportation Plans. The draft Plans are available on our...

  14. 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.

  15. 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.

  16. 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…

  17. 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

  18. 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.

  19. 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.

  20. 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

  1. 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.

  2. 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...

  3. 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…

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. Creating Strategic Vision: Long-Range Planning for National Security

    DTIC Science & Technology

    1987-07-01

    University Review, November-December 1979, pp. 49-54). Colonel Gene Davis, an Air Force long-range planner in 1980-1981, Institutionalizing Long-Range...Boulder, Colorado: Westview Press, 1982. Davis, Gene H. "Three R’s of Air Force Planning." The Bureaucrat, Summer 1982, pp. 51-53. Drucker, Peter F...simulation connotes an imitation of the behavior of a system over time or a dynamic representation of reality. 25 A simulation captures rela- tionships

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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

  16. 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.

  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. 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.

  19. 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

    Aaron Lewis,; 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. 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.

  7. 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…

  8. 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…

  9. 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…

  10. [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…

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. Development of a Long-Range Underwater Vehicle

    DTIC Science & Technology

    2015-09-30

    hull. 2 Batteries are a significant part of a glider payload so a new glider design is needed to use seawater batteries. Consequently, our...use in marine vehicles. 2. Design a prototype long-range underwater vehicle to exploit the new power source. 3. Build and report the field...carry out field tests, and head up new -vehicle design studies. The approach for battery testing was to characterize battery performance in laboratory

  3. 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).

  4. 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.

  5. Futures/Long-Range Planning Group. Periodic Report 7,

    DTIC Science & Technology

    1982-11-01

    27 interface for 21st century travelers. In a cashless , checkless society , Asimov envisages that travelers will have plastic devices (similar to...are: Antarctica, America’s aging population, divided societies , American-English, ethnotronics, and long-range planning. An introductory page presents...States can be reasonably projected for the next 50 years because projections depend on death rates and not on birth rates.󈧐 Increasingly, US society will

  6. LOAPEX: The Long-Range Ocean Acoustic Propagation EXperiment

    DTIC Science & Technology

    2009-01-01

    C. Eriksen, T. J. Osse, R. D. Light, T. Wen, T. W. Lehman, P. L. Sabin, J. W. Ballard, and A. M . Chiodi , “Seaglider: A long range autonomous...Propagation EXperiment James A. Mercer, John A. Colosi, Bruce M . Howe, Matthew A. Dzieciuch, Ralph Stephen, and Peter F. Worcester Abstract—This paper...from various depths to a pair of vertical hydrophone arrays covering 3500 m of the water column, and to several bottom-mounted horizontal line arrays

  7. 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.

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  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

    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.

  20. 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

  1. 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.

  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. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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

  15. 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).

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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

  7. 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.

  8. Hybrid Long-Range Collision Avoidance for Crowd Simulation.

    PubMed

    Golas, Abhinav; Narain, Rahul; Curtis, Sean; Lin, Ming C

    2014-07-01

    Local collision avoidance algorithms in crowd simulation often ignore agents beyond a neighborhood of a certain size. This cutoff can result in sharp changes in trajectory when large groups of agents enter or exit these neighborhoods. In this work, we exploit the insight that exact collision avoidance is not necessary between agents at such large distances, and propose a novel algorithm for extending existing collision avoidance algorithms to perform approximate, long-range collision avoidance. Our formulation performs long-range collision avoidance for distant agent groups to efficiently compute trajectories that are smoother than those obtained with state-of-the-art techniques and at faster rates. Comparison to real-world data demonstrates that crowds simulated with our algorithm exhibit an improved speed sensitivity to density similar to human crowds. Another issue often sidestepped in existing work is that discrete and continuum collision avoidance algorithms have different regions of applicability. For example, low-density crowds cannot be modeled as a continuum, while high-density crowds can be expensive to model using discrete methods. We formulate a hybrid technique for crowd simulation which can accurately and efficiently simulate crowds at any density with seamless transitions between continuum and discrete representations. Our approach blends results from continuum and discrete algorithms, based on local density and velocity variance. In addition to being robust across a variety of group scenarios, it is also highly efficient, running at interactive rates for thousands of agents on portable systems.

  9. Hybrid Long-Range Collision Avoidance for Crowd Simulation.

    PubMed

    Golas, Abhinav; Narain, Rahul; Curtis, Sean; Lin, Ming C

    2013-09-26

    Local collision avoidance algorithms in crowd simulation often ignore agents beyond a neighborhood of a certain size. This cutoff can result in sharp changes in trajectory when large groups of agents enter or exit these neighborhoods. In this work, we exploit the insight that exact collision avoidance is not necessary between agents at such large distances, and propose a novel algorithm for extending existing collision avoidance algorithms to perform approximate, long-range collision avoidance. Our formulation performs long-range collision avoidance for distant agent groups to efficiently compute trajectories that are smoother than those obtained with state-of-the-art techniques and at faster rates. Another issue often sidestepped in existing work is that discrete and continuum collision avoidance algorithms have different regions of applicability. For example, low-density crowds cannot be modeled as a continuum, while high-density crowds can be expensive to model using discrete methods. We formulate a hybrid technique for crowd simulation which can accurately and efficiently simulate crowds at any density with seamless transitions between continuum and discrete representations. Our approach blends results from continuum and discrete algorithms, based on local density and velocity variance. In addition to being robust across a variety of group scenarios, it is also highly efficient, running at interactive rates for thousands of agents on portable systems.

  10. 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.

  11. 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.

  12. 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

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  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. 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.

  11. 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.

  12. 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

  13. 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.

  14. 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.

  15. 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

  16. 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.

  17. 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

  18. 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

  19. 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

  20. 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.

  1. 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.

  2. 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

  3. 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

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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

  15. 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.

  16. 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.

  17. 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.

  18. 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

  19. 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...

  20. 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...

  1. 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...

  2. 25 CFR 170.410 - What is the purpose of tribal long-range transportation planning?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 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...

  3. 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...

  4. 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...

  5. 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...

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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).

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. 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

  5. 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.

  6. 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

  7. 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.

  8. 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.

  9. 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

  10. 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

  11. 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.

  12. 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...

  13. 23 CFR 450.214 - Development and content of the long-range statewide transportation plan.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 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 shall develop a long-range statewide transportation plan, with a minimum 20-year forecast period at...

  14. 23 CFR 450.214 - Development and content of the long-range statewide transportation plan.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 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 shall develop a long-range statewide transportation plan, with a minimum 20-year forecast period at...

  15. 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...

  16. 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...

  17. 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...

  18. 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...

  19. 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…

  20. 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.

  1. 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.

  2. 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…

  3. 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…

  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. 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.

  6. 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.

  7. 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

  8. 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

  9. 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

  10. 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....

  11. 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....

  12. 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... long-range acquisition estimates....

  13. 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...

  14. 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....

  15. 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....

  16. 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... long-range acquisition estimates....

  17. 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... Release of long-range acquisition estimates....

  18. 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...

  19. 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....

  20. 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....

  1. 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....

  2. 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....

  3. 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....

  4. 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...-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....

  5. 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....

  6. 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....

  7. 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....

  8. 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....

  9. 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....

  10. 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....

  11. 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....

  12. 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....

  13. 48 CFR 5.404-2 - Announcements of long-range acquisition estimates.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...-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 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....

  15. 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...

  16. 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....

  17. 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....

  18. 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... Release of long-range acquisition estimates....

  19. 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...

  20. 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…

  1. 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.

  2. 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...

  3. 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...

  4. 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...

  5. 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...

  6. 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...

  7. 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.

  8. 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...

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. Collapse of long-range charge order tracked by time-resolved photoemission at high momenta.

    PubMed

    Rohwer, Timm; Hellmann, Stefan; Wiesenmayer, Martin; Sohrt, Christian; Stange, Ankatrin; Slomski, Bartosz; Carr, Adra; Liu, Yanwei; Avila, Luis Miaja; Kalläne, Matthias; Mathias, Stefan; Kipp, Lutz; Rossnagel, Kai; Bauer, Michael

    2011-03-24

    Intense femtosecond (10(-15) s) light pulses can be used to transform electronic, magnetic and structural order in condensed-matter systems on timescales of electronic and atomic motion. This technique is particularly useful in the study and in the control of materials whose physical properties are governed by the interactions between multiple degrees of freedom. Time- and angle-resolved photoemission spectroscopy is in this context a direct and comprehensive, energy- and momentum-selective probe of the ultrafast processes that couple to the electronic degrees of freedom. Previously, the capability of such studies to access electron momentum space away from zero momentum was, however, restricted owing to limitations of the available probing photon energy. Here, using femtosecond extreme-ultraviolet pulses delivered by a high-harmonic-generation source, we use time- and angle-resolved photoemission spectroscopy to measure the photoinduced vaporization of a charge-ordered state in the potential excitonic insulator 1T-TiSe(2 )(refs 12, 13). By way of stroboscopic imaging of electronic band dispersions at large momentum, in the vicinity of the edge of the first Brillouin zone, we reveal that the collapse of atomic-scale periodic long-range order happens on a timescale as short as 20 femtoseconds. The surprisingly fast response of the system is assigned to screening by the transient generation of free charge carriers. Similar screening scenarios are likely to be relevant in other photoinduced solid-state transitions and may generally determine the response times. Moreover, as electron states with large momenta govern fundamental electronic properties in condensed matter systems, we anticipate that the experimental advance represented by the present study will be useful to study the ultrafast dynamics and microscopic mechanisms of electronic phenomena in a wide range of materials.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Long-Range Forecasting in Support of Operations in the Horn of Africa

    DTIC Science & Technology

    2010-09-01

    75 D. LONG-RANGE HINDCAST CASE STUDIES .................................... 77 1. 2009 ...have their greatest impact on the HOA short rains period in October– December. Figure from Hunt ( 2009 ...related variables (right box). Figure from Funk ( 2009

  20. 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.

  1. 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).

  2. 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.

  3. 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...

  4. 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.

  5. 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.

  6. 25 CFR 170.412 - How is the tribal IRR long-range transportation plan developed and approved?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 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 170.412 - 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...

  8. 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...

  9. 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...

  10. 25 CFR 170.414 - How is the tribal long-range transportation plan used and updated?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 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...

  11. 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...

  12. 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...

  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. 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

  15. 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.

  16. Climate Analysis and Long Range Forecasting of Dust Storms in Iraq

    DTIC Science & Technology

    2009-06-01

    Miller, S. D. 2007: COAMPS Real-Time Dust Storm Forecasting during Operation Iraqi Freedom. Weather and Forecasting 22:192-206. Moss, S., 2007...LONG RANGE FORECASTING OF DUST STORMS IN IRAQ by Jacquelyn Crook June 2009 Thesis Advisor: Tom Murphree Co-Advisor: Rebecca Stone...Master’s Thesis 4. TITLE AND SUBTITLE Climate Analysis and Long Range Forecasting of Dust Storms in Iraq 6. AUTHOR(S) Jacquelyn C Crook 5

  17. 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.

  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. 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.

  20. 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

  1. A Multi-Sensor Fusion MAV State Estimation from Long-Range Stereo, IMU, GPS and Barometric Sensors.

    PubMed

    Song, Yu; Nuske, Stephen; Scherer, Sebastian

    2016-12-22

    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.

  2. 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

  3. Moths Behaving like Butterflies. Evolutionary Loss of Long Range Attractant Pheromones in Castniid Moths: A Paysandisia archon Model

    PubMed Central

    Sarto i Monteys, Víctor; Acín, Patricia; Rosell, Glòria; Quero, Carmen; Jiménez, Miquel A.; Guerrero, Angel

    2012-01-01

    Background In the course of evolution butterflies and moths developed two different reproductive behaviors. Whereas butterflies rely on visual stimuli for mate location, moths use the ‘female calling plus male seduction’ system, in which females release long-range sex pheromones to attract conspecific males. There are few exceptions from this pattern but in all cases known female moths possess sex pheromone glands which apparently have been lost in female butterflies. In the day-flying moth family Castniidae (“butterfly-moths”), which includes some important crop pests, no pheromones have been found so far. Methodology/Principal Findings Using a multidisciplinary approach we described the steps involved in the courtship of P. archon, showing that visual cues are the only ones used for mate location; showed that the morphology and fine structure of the antennae of this moth are strikingly similar to those of butterflies, with male sensilla apparently not suited to detect female-released long range pheromones; showed that its females lack pheromone-producing glands, and identified three compounds as putative male sex pheromone (MSP) components of P. archon, released from the proximal halves of male forewings and hindwings. Conclusions/Significance This study provides evidence for the first time in Lepidoptera that females of a moth do not produce any pheromone to attract males, and that mate location is achieved only visually by patrolling males, which may release a pheromone at short distance, putatively a mixture of Z,E-farnesal, E,E-farnesal, and (E,Z)-2,13-octadecadienol. The outlined behavior, long thought to be unique to butterflies, is likely to be widespread in Castniidae implying a novel, unparalleled butterfly-like reproductive behavior in moths. This will also have practical implications in applied entomology since it signifies that the monitoring/control of castniid pests should not be based on the use of female-produced pheromones, as it is

  4. Comparing the performance of FA, DFA and DMA using different synthetic long-range correlated time series

    PubMed Central

    Shao, Ying-Hui; Gu, Gao-Feng; Jiang, Zhi-Qiang; Zhou, Wei-Xing; Sornette, Didier

    2012-01-01

    Notwithstanding the significant efforts to develop estimators of long-range correlations (LRC) and to compare their performance, no clear consensus exists on what is the best method and under which conditions. In addition, synthetic tests suggest that the performance of LRC estimators varies when using different generators of LRC time series. Here, we compare the performances of four estimators [Fluctuation Analysis (FA), Detrended Fluctuation Analysis (DFA), Backward Detrending Moving Average (BDMA), and Centred Detrending Moving Average (CDMA)]. We use three different generators [Fractional Gaussian Noises, and two ways of generating Fractional Brownian Motions]. We find that CDMA has the best performance and DFA is only slightly worse in some situations, while FA performs the worst. In addition, CDMA and DFA are less sensitive to the scaling range than FA. Hence, CDMA and DFA remain “The Methods of Choice” in determining the Hurst index of time series. PMID:23150785

  5. Chaotic dynamics and thermodynamics of periodic systems with long-range forces

    NASA Astrophysics Data System (ADS)

    Kumar, Pankaj

    Gravitational and electromagnetic interactions form the backbone of our theoretical understanding of the universe. While, in general, such interactions are analytically inexpressible for three-dimensional infinite systems, one-dimensional modeling allows one to treat the long-range forces exactly. Not only are one-dimensional systems of profound intrinsic interest, physicists often rely on one-dimensional models as a starting point in the analysis of their more complicated higher-dimensional counterparts. In the analysis of large systems considered in cosmology and plasma physics, periodic boundary conditions are a natural choice and have been utilized in the study of one dimensional Coulombic and gravitational systems. Such studies often employ numerical simulations to validate the theoretical predictions, and in cases where theoretical relations have not been mathematically formulated, numerical simulations serve as a powerful method in characterizing the system's physical properties. In this dissertation, analytic techniques are formulated to express the exact phase-space dynamics of spatially-periodic one-dimensional Coulombic and gravitational systems. Closed-form versions of the Hamiltonian and the electric field are derived for single-component and two-component Coulombic systems, placing the two on the same footing as the gravitational counterpart. Furthermore, it is demonstrated that a three-body variant of the spatially-periodic Coulombic or gravitational system may be reduced isomorphically to a periodic system of a single particle in a two-dimensional rhombic potential. The analytic results are utilized for developing and implementing efficient computational tools to study the dynamical and the thermodynamic properties of the systems without resorting to numerical approximations. Event-driven algorithms are devised to obtain Lyapunov spectra, radial distribution function, pressure, caloric curve, and Poincare surface of section through an N

  6. Long-Range Epistasis Mediated by Structural Change in a Model of Ligand Binding Proteins.

    PubMed

    Nelson, Erik D; Grishin, Nick V

    2016-01-01

    Recent analyses of amino acid mutations in proteins reveal that mutations at many pairs of sites are epistatic-i.e., their effects on fitness are non-additive-the combined effect of two mutations being significantly larger or smaller than the sum of their effects considered independently. Interestingly, epistatic sites are not necessarily near each other in the folded structure of a protein, and may even be located on opposite sides of a molecule. However, the mechanistic reasons for long-range epistasis remain obscure. Here, we study long-range epistasis in proteins using a previously developed model in which off-lattice polymers are evolved under ligand binding constraints. Epistatic effects in the model are qualitatively similar to those recently reported for small proteins, and many are long-range. We find that a major reason for long-range epistasis is conformational change-a recurrent theme in both positive and negative epistasis being the transfer, or exchange of material between the ordered nucleus, which supports the binding site, and the liquid-like surface of a folded molecule. These local transitions in phase and folded structure are largely responsible for long-range epistasis in our model.

  7. Assessing very long-range impacts from a rapid climate change

    SciTech Connect

    Markley, O.W.; Hall, P.R.

    1982-01-01

    A variety of anthropogenic, or human-generated forces are gradually changing global climate. These include effects due to slash and burn agriculture, industrial particulates, waste heat and gasses such as chlorofluoromethanes, nitrous oxide, and carbon dioxide. Although the short-range effects of these forces may seem to be relatively minor from a long-range perspective, climatologists warn that the long-range effects - especially of increases in atmospheric carbon dioxide resulting from widespread fossil fuel use - will be great, bringing significant alterations in atmospheric temperature, wind and ocean currents, precipitation patterns, and other ecological phenomena. From a geological time perspective, the resulting climate changes will occur quite rapidly, and will affect human concerns in a number of ways. Besides being important for long-range social planning, these effects are of intrinsic interest to futures research and impact assessment methodologists. Although many uncertainties exist in long-range climate forecasting, climate change comprises one of the very few classes of phenomena where the nature of very long-range (i.e., 30 to 3000 years) impact-producing changes are feasible to forecast in reasonably rigorous, quantitative terms.

  8. Aberrant long-range functional connectivity density in generalized tonic-clonic seizures.

    PubMed

    Zhu, Ling; Li, Yibo; Wang, Yifeng; Li, Rong; Zhang, Zhiqiang; Lu, Guangming; Chen, Huafu

    2016-06-01

    Studies in generalized tonic-clonic seizures (GTCS) have reported both structural and functional alterations in the brain. However, changes in spontaneous neuronal functional organization in GTCS remain largely unknown.In this study, 70 patients with idiopathic generalized epilepsy characterized by tonic-clonic seizures and 70 age- and sex-matched healthy controls were recruited. Here, functional connectivity density (FCD) mapping, an ultrafast data-driven method based on functional magnetic resonance imaging (fMRI), was applied for the first time to investigate the changes of spontaneous functional brain activity caused by epilepsy.The results showed significantly decreased long-range FCD in the middle and inferior temporal, prefrontal, and inferior parietal cortices as well as increased long-range FCD in the cerebellum anterior lobe and sensorimotor areas. Negative correlation between duration of disease and reduced long-range FCD was found. In addition, most regions with reduced long-range FCD showed decreased resting-state functional connectivity (rsFC) within default mode network.Negative correlation between duration of disease and long-range FCD may reflect an adverse consequence eventually from original. Furthermore, the observed FCD and rsFC alterations have been speculated to be associated with the social-cognitive impairments as well as motor control. Our study provided novel evidences to look into neuro-pathophysiological mechanisms underlying GTCS.

  9. Long-Range Coulomb Effect in Intense Laser-Driven Photoelectron Dynamics

    PubMed Central

    Quan, Wei; Hao, XiaoLei; Chen, YongJu; Yu, ShaoGang; Xu, SongPo; Wang, YanLan; Sun, RenPing; Lai, XuanYang; Wu, ChengYin; Gong, QiHuang; He, XianTu; Liu, XiaoJun; Chen, Jing

    2016-01-01

    In strong field atomic physics community, long-range Coulomb interaction has for a long time been overlooked and its significant role in intense laser-driven photoelectron dynamics eluded experimental observations. Here we report an experimental investigation of the effect of long-range Coulomb potential on the dynamics of near-zero-momentum photoelectrons produced in photo-ionization process of noble gas atoms in intense midinfrared laser pulses. By exploring the dependence of photoelectron distributions near zero momentum on laser intensity and wavelength, we unambiguously demonstrate that the long-range tail of the Coulomb potential (i.e., up to several hundreds atomic units) plays an important role in determining the photoelectron dynamics after the pulse ends. PMID:27256904

  10. Fractality Evidence and Long-Range Dependence on Capital Markets: a Hurst Exponent Evaluation

    NASA Astrophysics Data System (ADS)

    Oprean, Camelia; Tănăsescu, Cristina

    2014-07-01

    Since the existence of market memory could implicate the rejection of the efficient market hypothesis, the aim of this paper is to find any evidence that selected emergent capital markets (eight European and BRIC markets, namely Hungary, Romania, Estonia, Czech Republic, Brazil, Russia, India and China) evince long-range dependence or the random walk hypothesis. In this paper, the Hurst exponent as calculated by R/S fractal analysis and Detrended Fluctuation Analysis is our measure of long-range dependence in the series. The results reinforce our previous findings and suggest that if stock returns present long-range dependence, the random walk hypothesis is not valid anymore and neither is the market efficiency hypothesis.

  11. Nucleation in the presence of long-range interactions. [performed on ferroelectric barium titanate

    NASA Technical Reports Server (NTRS)

    Chandra, P.

    1989-01-01

    Unlike droplet nucleation near a liquid-gas critical point, the decay of metastable phases in crystalline materials is strongly affected by the presence of long-range forces. Field quench experiments performed on the ferroelectric barium titanate indicate that nucleation in this material is markedly different from that observed in liquids. In this paper, a theory for nucleation at a first-order phase transition in which the mediating forces are long range is presented. It is found that the long-range force induces cooperative nucleation and growth processes, and that this feedback mechanism produces a well-defined delay time with a sharp onset in the transformation to the stable phase. Closed-form expressions for the characteristic onset time and width of the transition are developed, in good agreement with numerical and experimental results.

  12. Long-range ordered vorticity patterns in living tissue induced by cell division.

    PubMed

    Rossen, Ninna S; Tarp, Jens M; Mathiesen, Joachim; Jensen, Mogens H; Oddershede, Lene B

    2014-12-08

    In healthy blood vessels with a laminar blood flow, the endothelial cell division rate is low, only sufficient to replace apoptotic cells. The division rate significantly increases during embryonic development and under halted or turbulent flow. Cells in barrier tissue are connected and their motility is highly correlated. Here we investigate the long-range dynamics induced by cell division in an endothelial monolayer under non-flow conditions, mimicking the conditions during vessel formation or around blood clots. Cell divisions induce long-range, well-ordered vortex patterns extending several cell diameters away from the division site, in spite of the system's low Reynolds number. Our experimental results are reproduced by a hydrodynamic continuum model simulating division as a local pressure increase corresponding to a local tension decrease. Such long-range physical communication may be crucial for embryonic development and for healing tissue, for instance around blood clots.

  13. Long-range ordered vorticity patterns in living tissue induced by cell division

    PubMed Central

    Rossen, Ninna S.; Tarp, Jens M.; Mathiesen, Joachim; Jensen, Mogens H.; Oddershede, Lene B.

    2014-01-01

    In healthy blood vessels with a laminar blood flow, the endothelial cell division rate is low, only sufficient to replace apoptotic cells. The division rate significantly increases during embryonic development and under halted or turbulent flow. Cells in barrier tissue are connected and their motility is highly correlated. Here we investigate the long-range dynamics induced by cell division in an endothelial monolayer under non-flow conditions, mimicking the conditions during vessel formation or around blood clots. Cell divisions induce long-range, well-ordered vortex patterns extending several cell diameters away from the division site, in spite of the system’s low Reynolds number. Our experimental results are reproduced by a hydrodynamic continuum model simulating division as a local pressure increase corresponding to a local tension decrease. Such long-range physical communication may be crucial for embryonic development and for healing tissue, for instance around blood clots. PMID:25483750

  14. UTag: Long-range Ultra-wideband Passive Radio Frequency Tags

    SciTech Connect

    Dowla, F

    2007-03-14

    Long-range, ultra-wideband (UWB), passive radio frequency (RF) tags are key components in Radio Frequency IDentification (RFID) system that will revolutionize inventory control and tracking applications. Unlike conventional, battery-operated (active) RFID tags, LLNL's small UWB tags, called 'UTag', operate at long range (up to 20 meters) in harsh, cluttered environments. Because they are battery-less (that is, passive), they have practically infinite lifetimes without human intervention, and they are lower in cost to manufacture and maintain than active RFID tags. These robust, energy-efficient passive tags are remotely powered by UWB radio signals, which are much more difficult to detect, intercept, and jam than conventional narrowband frequencies. The features of long range, battery-less, and low cost give UTag significant advantage over other existing RFID tags.

  15. Emergent long-range synchronization of oscillating ecological populations without external forcing described by Ising universality

    PubMed Central

    Noble, Andrew E.; Machta, Jonathan; Hastings, Alan

    2015-01-01

    Understanding the synchronization of oscillations across space is fundamentally important to many scientific disciplines. In ecology, long-range synchronization of oscillations in spatial populations may elevate extinction risk and signal an impending catastrophe. The prevailing assumption is that synchronization on distances longer than the dispersal scale can only be due to environmental correlation (the Moran effect). In contrast, we show how long-range synchronization can emerge over distances much longer than the length scales of either dispersal or environmental correlation. In particular, we demonstrate that the transition from incoherence to long-range synchronization of two-cycle oscillations in noisy spatial population models is described by the Ising universality class of statistical physics. This result shows, in contrast to all previous work, how the Ising critical transition can emerge directly from the dynamics of ecological populations. PMID:25851364

  16. Emergent long-range synchronization of oscillating ecological populations without external forcing described by Ising universality.

    PubMed

    Noble, Andrew E; Machta, Jonathan; Hastings, Alan

    2015-04-08

    Understanding the synchronization of oscillations across space is fundamentally important to many scientific disciplines. In ecology, long-range synchronization of oscillations in spatial populations may elevate extinction risk and signal an impending catastrophe. The prevailing assumption is that synchronization on distances longer than the dispersal scale can only be due to environmental correlation (the Moran effect). In contrast, we show how long-range synchronization can emerge over distances much longer than the length scales of either dispersal or environmental correlation. In particular, we demonstrate that the transition from incoherence to long-range synchronization of two-cycle oscillations in noisy spatial population models is described by the Ising universality class of statistical physics. This result shows, in contrast to all previous work, how the Ising critical transition can emerge directly from the dynamics of ecological populations.

  17. Long range forecasts of the Northern Hemisphere anomalies with antecedent sea surface temperature patterns

    NASA Technical Reports Server (NTRS)

    Kung, Ernest C.

    1994-01-01

    The contract research has been conducted in the following three major areas: analysis of numerical simulations and parallel observations of atmospheric blocking, diagnosis of the lower boundary heating and the response of the atmospheric circulation, and comprehensive assessment of long-range forecasting with numerical and regression methods. The essential scientific and developmental purpose of this contract research is to extend our capability of numerical weather forecasting by the comprehensive general circulation model. The systematic work as listed above is thus geared to developing a technological basis for future NASA long-range forecasting.

  18. Long-range corrected density functional theory with linearly-scaled HF exchange

    NASA Astrophysics Data System (ADS)

    Song, Jong-Won; Hirao, Kimihiko

    2015-12-01

    Long-range corrected density functional theory (LC-DFT) attracts many chemists' attentions as a quantum chemical method to be applied to large molecular system and its property calculations. However, the expensive time cost to evaluate the long-range HF exchange is a big obstacle to be overcome to be applied to the large molecular systems and the solid state materials. Upon this problem, we propose a linear-scaling method of the HF exchange integration, in particular, for the LC-DFT hybrid functional.

  19. Constraining long-range parity violation in gravitation using high resolution spectroscopy of chiral molecules

    NASA Astrophysics Data System (ADS)

    Bargueño, Pedro; Pérez de Tudela, Ricardo

    2008-11-01

    New bounds on long-range parity violation in gravitation are reported from inconclusive searches of parity violating energy differences (PVED) in chiral molecules. In particular, it is found that Leitner-Okubo-Hari Dass’s α2 (or A2) parameter is constrained by current experimental searches of PVED between molecular enantiomers. The possibility of constraining other parameters which parametrize the strength of contact parity violation in gravity, as well as other long-range parity violating potentials will be briefly commented.

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

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

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

  1. Long range electronic transport in microbial nanowires bridging an electrode and scanned probe

    NASA Astrophysics Data System (ADS)

    Veazey, Joshua; Lampa-Pastirk, Sanela; Walsh, Kathy; Sun, Jiebing; Zhang, Pengpeng; Reguera, Gemma; Tessmer, Stuart

    2011-03-01

    The filament-like appendages known as pili, expressed by the bacterium Geobacter sulfurreducens, are believed to act as electrically conductive nanowires. Previously, we used scanning tunneling microscopy to study the local density of states at different positions along the wire. However, the long range electron transfer believed to occur in this protein has not been directly observed. Here we discuss a system for verifying long range transport using a scanning probe technique. Transport at distances of more than a few nanometers would require a novel biological electron transfer process. The authors gratefully acknowledge support from the National Science Foundation (MCB-1021948) and the Michigan State University Foundation (Strategic Partnership Grant).

  2. Long-range corrected density functional theory with linearly-scaled HF exchange

    SciTech Connect

    Song, Jong-Won; Hirao, Kimihiko

    2015-12-31

    Long-range corrected density functional theory (LC-DFT) attracts many chemists’ attentions as a quantum chemical method to be applied to large molecular system and its property calculations. However, the expensive time cost to evaluate the long-range HF exchange is a big obstacle to be overcome to be applied to the large molecular systems and the solid state materials. Upon this problem, we propose a linear-scaling method of the HF exchange integration, in particular, for the LC-DFT hybrid functional.

  3. Long-range airplane study: The consumer looks at SST travel

    NASA Technical Reports Server (NTRS)

    Landes, K. H.; Matter, J. A.

    1980-01-01

    The attitudes of long-range air travelers toward several basic air travel decisions, were surveyed. Of interest were tradeoffs involving time versus comfort and time versus cost as they pertain to supersonic versus conventional wide-body aircraft on overseas routes. The market focused upon was the segment of air travelers most likely to make that type of tradeoff decision: those having flown overseas routes for business or personal reasons in the recent past. The information generated is intended to provide quantifiable insight into consumer demand for supersonic as compared to wide-body aircraft alternatives for long-range overseas air travel.

  4. TU-F-CAMPUS-I-01: Head and Neck Squamous Cell Carcinoma: Short-Term Repeatability of Apparent Diffusion Coefficient and Intravoxel Incoherent Motion Parameters at 3.0T

    SciTech Connect

    Ding, Y; Fuller, C; Mohamed, A; Wang, J; Hazle, J

    2015-06-15

    Purpose: Many published studies have recently demonstrated the potential value of intravoxel incoherent motion (IVIM) analysis for disease evaluation. However, few have questioned its measurement repeatability/reproducibility when applied. The purpose of this study was to determine the short-term measurement repeatability of apparent diffusion coefficient ADC, true diffusion coefficient D, pseudodiffusion coefficient D* and perfusion fraction f, in head and neck squamous cell carcinoma (HNSCC) primary tumors and metastatic nodes. Methods: Ten patients with known HNSCC were examined twice using echo-planar DW-MRI with 12 b values (0 to 800 s/mm2) 1hour to 24 hours apart before radiation treatment. All patients were scanned with the customized radiation treatment immobilization devices to reduce motion artifacts and to improve image registration in repeat scans. Regions of interests were drawn in primary tumor and metastases node in each patient (Fig. 1). ADC and IVIM parameters D, D* and f were calculated by least squares data fitting. Short-term test–retest repeatability of ADC and IVIM parameters were assessed by measuring Bland–Altman limits of agreements (BA-LA). Results: Sixteen HNSCC lesions were assessed in 10 patients. Repeatability of perfusion-sensitive parameters, D* and f, in HNSCC lesions was poor (BA-LA: -144% to 88% and −57% to 96% for D* and f, respectively); a lesser extent was observed for the diffusion-sensitive parameters of ADC and D (BA-LA: −34% to 39% and −37% to 40%, for ADC and D, respectively) (Fig. 2). Conclusion: Poor repeatability of D*/f and good repeatability for ADC/D were observed in HNSCC primary tumors and metastatic nodes. Efforts should be made to improve the measurement repeatability of perfusion-sensitive IVIM parameters.

  5. The pluripotent regulatory circuitry connecting promoters to their long-range interacting elements

    PubMed Central

    Schoenfelder, Stefan; Furlan-Magaril, Mayra; Mifsud, Borbala; Tavares-Cadete, Filipe; Sugar, Robert; Javierre, Biola-Maria; Nagano, Takashi; Katsman, Yulia; Sakthidevi, Moorthy; Wingett, Steven W.; Dimitrova, Emilia; Dimond, Andrew; Edelman, Lucas B.; Elderkin, Sarah; Tabbada, Kristina; Darbo, Elodie; Andrews, Simon; Herman, Bram; Higgs, Andy; LeProust, Emily; Osborne, Cameron S.; Mitchell, Jennifer A.

    2015-01-01

    The mammalian genome harbors up to one million regulatory elements often located at great distances from their target genes. Long-range elements control genes through physical contact with promoters and can be recognized by the presence of specific histone modifications and transcription factor binding. Linking regulatory elements to specific promoters genome-wide is currently impeded by the limited resolution of high-throughput chromatin interaction assays. Here we apply a sequence capture approach to enrich Hi-C libraries for >22,000 annotated mouse promoters to identify statistically significant, long-range interactions at restriction fragment resolution, assigning long-range interacting elements to their target genes genome-wide in embryonic stem cells and fetal liver cells. The distal sites contacting active genes are enriched in active histone modifications and transcription factor occupancy, whereas inactive genes contact distal sites with repressive histone marks, demonstrating the regulatory potential of the distal elements identified. Furthermore, we find that coregulated genes cluster nonrandomly in spatial interaction networks correlated with their biological function and expression level. Interestingly, we find the strongest gene clustering in ES cells between transcription factor genes that control key developmental processes in embryogenesis. The results provide the first genome-wide catalog linking gene promoters to their long-range interacting elements and highlight the complex spatial regulatory circuitry controlling mammalian gene expression. PMID:25752748

  6. Quantum transport with long-range steps on Watts-Strogatz networks

    NASA Astrophysics Data System (ADS)

    Wang, Yan; Xu, Xin-Jian

    2016-07-01

    We study transport dynamics of quantum systems with long-range steps on the Watts-Strogatz network (WSN) which is generated by rewiring links of the regular ring. First, we probe physical systems modeled by the discrete nonlinear schrödinger (DNLS) equation. Using the localized initial condition, we compute the time-averaged occupation probability of the initial site, which is related to the nonlinearity, the long-range steps and rewiring links. Self-trapping transitions occur at large (small) nonlinear parameters for coupling ɛ=-1 (1), as long-range interactions are intensified. The structure disorder induced by random rewiring, however, has dual effects for ɛ=-1 and inhibits the self-trapping behavior for ɛ=1. Second, we investigate continuous-time quantum walks (CTQW) on the regular ring ruled by the discrete linear schrödinger (DLS) equation. It is found that only the presence of the long-range steps does not affect the efficiency of the coherent exciton transport, while only the allowance of random rewiring enhances the partial localization. If both factors are considered simultaneously, localization is greatly strengthened, and the transport becomes worse.

  7. INVESTIGATING THE INFLUENCE OF LONG RANGE TRANSPORT ON MERCURY DEPOSITION IN SOUTH FLORIDA

    EPA Science Inventory

    In 1999, the US EPA National Exposure Research Laboratory (NERL) through a Regional Applied Research Effort initiated a study to evaluate the magnitude of long-range transport of mercury through the marine free troposphere to South Florida via aircraft measurements (200 to 11,5...

  8. Teacher Self-Assessment Data: Bases for Designing a Personal Long-Range Professional Development Program.

    ERIC Educational Resources Information Center

    Askins, Billy E.

    A program of self-evaluation was developed for teachers to use in creating a personal profile which could become the basis for designing a long-range professional development program. Seven areas for self-assessment were philosophical belief system, personality traits, interpersonal awareness traits, self-concept, learning style, teaching style,…

  9. Long range ordered alloys modified by addition of niobium and cerium

    DOEpatents

    Liu, C.T.

    1984-08-22

    Long range ordered alloys are described having the nominal composition (Fe,Ni,Co)/sub 3/ (V,M) where M is a ductility enhancing metal selected from the group Ti, Zr, Hf with additions of small amounts of cerium and niobium to dramatically enhance the creep properties of the resulting alloys.

  10. Long range ordered alloys modified by addition of niobium and cerium

    DOEpatents

    Liu, Chain T.

    1987-01-01

    Long range ordered alloys are described having the nominal composition (Fe,Ni,Co).sub.3 (V,M) where M is a ductility enhancing metal selected from the group Ti, Zr, Hf with additions of small amounts of cerium and niobium to drammatically enhance the creep properties of the resulting alloys.

  11. Long Range Facilities Master Plan: 1986-2000, San Diego Unified School District.

    ERIC Educational Resources Information Center

    Blair, Billie; And Others

    The Long-Range Facilities Master Plan presents solution strategies and financing methods for accommodating a projected student enrollment increase of 45,000 between 1986 and 2000. This increase, plus limited financial resources, school use studies, and recent legislation, necessitated the plan. The issues include housing students, facility…

  12. NIDRR Long-Range Plan for Fiscal Years 2005-09. Executive Summary

    ERIC Educational Resources Information Center

    US Department of Education, 2007

    2007-01-01

    The National Institute on Disability and Rehabilitation Research (NIDRR) "Long-Range Plan for Fiscal Years 2005-09" (the "Plan") provides an agenda for achieving advancements in applied rehabilitation research that will benefit people with disabilities in the United States. This executive summary describes the purposes and…

  13. Space: The Long-Range Future: An Interview with Jesco von Puttkamer.

    ERIC Educational Resources Information Center

    Lawler, Andrew

    1985-01-01

    Jesco von Puttkamer manages long-range planning in NASA's Office of Space Flight. He believes that space offers the opportunity to ease global tensions, help the developing world, and create a new global culture off the planet. (Author/RM)

  14. The DeKalb Tech Model for Long-Range Planning.

    ERIC Educational Resources Information Center

    DeKalb Technical Inst., Clarkston, GA. Office of Research and Planning.

    The DeKalb Tech Model for Long-Range Planning provides the framework for a 3-year strategic planning document based on the Georgia State Board of Postsecondary Vocational Education's Evaluation, Planning, and Budgeting (EPB) process. The DeKalb Tech Model consists of five planning segments: (1) pre-planning, which includes the evaluation of…

  15. Towards theoretical analysis of long-range proton transfer kinetics in biomolecular pumps

    PubMed Central

    König, P. H.; Ghosh, N.; Hoffmann, M.; Elstner, M.; Tajkhorshid, E.; Frauenheim, Th.; Cui, Q.

    2008-01-01

    Motivated by the long-term goal of theoretically analyzing long-range proton transfer (PT) kinetics in biomolecular pumps, a number of technical developments were made in the framework of QM/MM simulations. A set of collective reaction co-ordinates is proposed for characterizing the progress of long-range proton transfers; unlike previous suggestions, the new coordinates can describe PT along highly non-linear three-dimensional pathways. Calculations using a realistic model of carbonic anhydrase demonstrated that adiabatic mapping using these collective coordinates gives reliable energetics and critical geometrical parameters as compared to minimum energy path calculations, which suggests that the new coordinates can be effectively used as reaction coordinate in potential of mean force calculations for long-range PT in complex systems. In addition, the generalized solvent boundary potential was implemented in the QM/MM framework for rectangular geometries, which is useful for studying reactions in membrane systems. The resulting protocol was found to produce water structure in the interior of aquaporin consistent with previous studies including much larger number of explicit solvent and lipid molecules. The effect of electrostatics for PT through membrane protein was also illustrated with a simple model channel embedded in different dielectric continuum environments. The encouraging results observed so far suggest that robust theoretical analysis of long-range PT kinetics in biomolecular pumps can soon be realized in a QM/MM framework. PMID:16405327

  16. The Long-Range Future of the Scientific Exploration of Mars

    NASA Astrophysics Data System (ADS)

    Johnson, J.; Beaty, D. W.; Bussey, B.; Christensen, P.; Hamilton, V.; Hubbard, S.; Meyer, M.; Ori, G.; Pratt, L.; Zurek, R.; Diniega, S.; Hays, L.

    2017-02-01

    Over the next three decades, if we assume that MSR has been completed, results may yield a Branch point in our long-range planning that revolves around the question: Do the samples contain either permissive or definitive evidence of martian life?

  17. Calculation of long range forces and their applications in determining gaseous properties

    NASA Technical Reports Server (NTRS)

    Singh, J. J.

    1979-01-01

    A discussion of various theoretical and experimental techniques for the calculation of long range interaction between two atomic systems at moderate separation is presented. Some applications of these techniques for obtaining gaseous properties are described. The forces between neutral molecules and metallic surfaces are also discussed and numerical values of heats of adsorption for a number of systems are calculated.

  18. Imputation of Missing Genotypes From Sparse to High Density Using Long-Range Phasing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Related individuals in a population share long chromosome segments which trace to a common ancestor. We describe a long-range phasing algorithm that makes use of this property to phase whole chromosomes and simultaneously impute a large number of missing markers. We test our method by imputing marke...

  19. Futures Research and the Strategic Planning Process: Implications for Long-Range Planning in Higher Education.

    ERIC Educational Resources Information Center

    Morrison, James L.; Renfro, William L.

    The concepts of long-range planning and strategic planning are explained, and a planning model is proposed. Attention is directed to an environmental scanning model that is congruent with the concept of strategic planning and that emerges from one portion of the futures research community, issues management. A third planning model, the strategic…

  20. Non-Local Propagation of Correlations in Quantum Systems with Long-Range Interactions

    DTIC Science & Technology

    2014-07-10

    LETTER doi:10.1038/nature13450 Non-local propagation of correlations in quantum systems with long-range interactions Philip Richerme1, Zhe -Xuan Gong1...2013). 29. James, D. F. V. Quantum dynamics of cold trapped ions with application to quantum computation. Appl. Phys. B 66, 181–190 (1998). 30. Wang

  1. Long range correlations in high multiplicity hadron collisions: Building bridges with ridges

    SciTech Connect

    Venugopalan, Raju

    2015-01-15

    We discuss the physics of the ridge–azimuthally collimated long range rapidity correlations–in high multiplicity proton–proton and proton–nucleus collisions. We outline some of the theoretical discussions in the literature that address the systematics of these ridge correlations.

  2. Long Range Plan for Statewide Library Development in Texas: 1994-1997.

    ERIC Educational Resources Information Center

    Texas State Library, Austin. Dept. of Library Development.

    The long range plan provides for the orderly establishment and expansion of programs needed to carry out the objectives of the Texas State Library. The following five major development goals were identified for the 1994-1997 period: (1) improve library services and increase library resources through financial support; (2) make materials and…

  3. Long Range Plan for Statewide Library Development in Texas: 1996 to 1999.

    ERIC Educational Resources Information Center

    Texas State Library, Austin. Dept. of Library Development.

    Texas State Library's 1996 to 1999 long range plan for library development provides for the establishment and expansion of programs needed to carry out the objectives of the Library Services and Construction Act (LSCA) and the Library Systems Act (LSA). The first three chapters give an overview of the Statewide Library Development Program of the…

  4. Next-Generation Long-Range Strike: Combating the Tyranny of Distance

    DTIC Science & Technology

    2011-02-16

    posed by a war in the Pacific, and in other parts of the world where forward basing is not an option, a next generation of penetrating and persistent...next generation of long-range strike capabilities. Discussion focuses on the capability requirements tempered with a strategy to ensure the acquisition

  5. Long Range Correlations and Phase Transitions in Non-equilibrium Diffusive Systems

    NASA Astrophysics Data System (ADS)

    Bodineau, T.; Derrida, B.; Lecomte, V.; van Wijland, F.

    2008-12-01

    We obtain explicit expressions for the long range correlations in the ABC model and in diffusive models conditioned to produce an atypical current of particles. In both cases, the two-point correlation functions allow one to detect the occurrence of a phase transition as they become singular when the system approaches the transition.

  6. Long-range dispersion interactions. III: Method for two homonuclear atoms

    SciTech Connect

    Mitroy, J.; Zhang, J.-Y.

    2007-12-15

    A procedure for systematically evaluating the long-range dispersion interaction between two homonuclear atoms in arbitrary LS coupled states is outlined. The method is then used to generate dispersion coefficients for a number of the low-lying states of the Na and Mg dimers.

  7. Toward theoretical analysis of long-range proton transfer kinetics in biomolecular pumps.

    PubMed

    König, P H; Ghosh, N; Hoffmann, M; Elstner, M; Tajkhorshid, E; Frauenheim, Th; Cui, Q

    2006-01-19

    Motivated by the long-term goal of theoretically analyzing long-range proton transfer (PT) kinetics in biomolecular pumps, researchers made a number of technical developments in the framework of quantum mechanics-molecular mechanics (QM/MM) simulations. A set of collective reaction coordinates is proposed for characterizing the progress of long-range proton transfers; unlike previous suggestions, the new coordinates can describe PT along highly nonlinear three-dimensional pathways. Calculations using a realistic model of carbonic anhydrase demonstrated that adiabatic mapping using these collective coordinates gives reliable energetics and critical geometrical parameters as compared to minimum energy path calculations, which suggests that the new coordinates can be effectively used as reaction coordinate in potential of mean force calculations for long-range PT in complex systems. In addition, the generalized solvent boundary potential was implemented in the QM/MM framework for rectangular geometries, which is useful for studying reactions in membrane systems. The resulting protocol was found to produce water structure in the interior of aquaporin consistent with previous studies including a much larger number of explicit solvent and lipid molecules. The effect of electrostatics for PT through a membrane protein was also illustrated with a simple model channel embedded in different dielectric continuum environments. The encouraging results observed so far suggest that robust theoretical analysis of long-range PT kinetics in biomolecular pumps can soon be realized in a QM/MM framework.

  8. Rapid, long range inspection of chemical plant pipework using guided waves

    NASA Astrophysics Data System (ADS)

    Alleyne, D. N.; Pavlakovic, B.; Lowe, M. J. S.; Cawley, P.

    2001-04-01

    Instrumentation for long range, guided wave inspection of pipework is now commercially available. This paper discusses the principles of the method and reviews the results of site experience. The technique was originally designed to work on pipes that were either un-coated or covered with, for example, epoxy paint. Recent tests have shown promising results with more attenuative coatings and these are discussed.

  9. Geometrical and Anderson transitions in harmonic chains with constrained long-range couplings.

    PubMed

    Morais, P A; Andrade, J S; Nascimento, E M; Lyra, M L

    2011-10-01

    Low-dimensional systems with long-range couplings usually present phase transitions which are absent in the short-ranged counterpart model. In this work, we show that a harmonic chain with long-range couplings restricted by a cost function proportional to the chain length N exhibits two distinct phase transitions. In the present model, two sites at a distance r>1 are connected by a spring with probability 1/r(α) with the constraint that the total length of the non-nearest-neighbor couplings is limited to λN, where λ is a cost parameter. A geometrical phase transition is found at α=1.5 between a phase with a finite number of long-range couplings and a phase on which the number of long-range couplings is proportional to the system size. Further, the normal vibrational modes of this chain display a phase transition from delocalized to localized modes at a smaller value of α. Maximum effective disorder is reached at α=2 for which the frequency of the lowest vibrational mode exhibits a pronounced peak.

  10. Measurement and applications of long-range heteronuclear scalar couplings: recent experimental and theoretical developments.

    PubMed

    Nath, Nilamoni; Lokesh; Suryaprakash, Nagarajarao

    2012-02-01

    The use of long-range heteronuclear couplings, in association with (1)H-(1)H scalar couplings and NOE restraints, has acquired growing importance for the determination of the relative stereochemistry, and structural and conformational information of organic and biological molecules. However, the routine use of such couplings is hindered by the inherent difficulties in their measurement. Prior to the advancement in experimental techniques, both long-range homo- and heteronuclear scalar couplings were not easily accessible, especially for very large molecules. The development of a large number of multidimensional NMR experimental methodologies has alleviated the complications associated with the measurement of couplings of smaller strengths. Subsequent application of these methods and the utilization of determined J-couplings for structure calculations have revolutionized this area of research. Problems in organic, inorganic and biophysical chemistry have also been solved by utilizing the short- and long-range heteronuclear couplings. In this minireview, we discuss the advantages and limitations of a number of experimental techniques reported in recent times for the measurement of long-range heteronuclear couplings and a few selected applications of such couplings. This includes the study of medium- to larger-sized molecules in a variety of applications, especially in the study of hydrogen bonding in biological systems. The utilization of these couplings in conjunction with theoretical calculations to arrive at conclusions on the hyperconjugation, configurational analysis and the effect of the electronegativity of the substituents is also discussed.

  11. Angular and Long Range Rapidity Correlations in Particle Production at High Energy

    NASA Astrophysics Data System (ADS)

    Kovner, Alex; Lublinsky, Michael

    2013-01-01

    We discuss the general mechanism leading to long-range rapidity and angular correlations produced in high energy collisions (the "ridge"). This effect naturally appears in the high energy QCD and is strongly sensitive to physics of the gluon saturation. We comment on various recent practical realizations of the main idea, paying special attention to Nc counting and stress the relevance of Pomeron loops.

  12. Application of powered-lift concepts for improved cruise efficiency of long-range aircraft

    NASA Technical Reports Server (NTRS)

    Coe, P. L., Jr.; Fournier, P. G.

    1976-01-01

    Results of studies conducted to explore the use of powered lift concepts for improved low speed performance of long range subsonic and supersonic cruise vehicles are summarized. It is indicated that powered lift can provide significant improvements in low speed performance, as well as substantial increases in cruise efficiency and range for both subsonic and supersonic cruise configurations.

  13. Global and Regional Modeling of Long-Range Transport and Intercontinental Source-Receptor Linkages (presentation)

    EPA Science Inventory

    Because long-range transport has been shown to affect air quality in downwind continents, there is a growing realization that these effects may need to be considered in air quality management efforts by distinguishing between the contributions of local and regional emission sourc...

  14. 75 FR 998 - Terminate Long Range Aids to Navigation (Loran-C) Signal

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-07

    ... 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..., the Department of Transportation has determined that sufficient alternative navigation aids...

  15. 25 CFR 170.413 - What is the public role in developing the long-range transportation plan?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false What is the public role in developing the long-range... Roads Program Facilities Long-Range Transportation Planning § 170.413 What is the public role in developing the long-range transportation plan? BIA or the tribe must solicit public involvement. If there...

  16. Singular dynamics and emergence of nonlocality in long-range quantum models

    NASA Astrophysics Data System (ADS)

    Lepori, L.; Trombettoni, A.; Vodola, D.

    2017-03-01

    We discuss how nonlocality originates in long-range quantum systems and how it affects their dynamics at and out of equilibrium. We focus in particular on the Kitaev chains with long-range pairings and on the quantum Ising chain with long-range antiferromagnetic coupling (both having a power-law decay with exponent α). By studying the dynamic correlation functions, we find that for every finite α two different behaviours can be identified, one typical of short-range systems and the other connected with locality violation. The latter behaviour is shown related also with the known power-law decay tails previously observed in the static correlation functions, and originated by modes—having in general energies far from the minima of the spectrum—where particular singularities develop as a consequence of the long-rangedness of the system. We refer to these modes as to ‘singular’ modes, and as to ‘singular dynamics’ to their dynamics. For the Kitaev model they are manifest, at finite α, in derivatives of the quasiparticle energy, the order of the derivatives at which the singularity occurs is increasing with α. The features of the singular modes and their physical consequences are clarified by studying an effective theory for them and by a critical comparison of the results from this theory with the lattice ones. Moreover, a numerical study of the effects of the singular modes on the time evolution after various types of global quenches is performed. We finally present and discuss the presence of singular modes and their consequences in interacting long-range systems by investigating in the long-range Ising quantum chain, both in the deep paramagnetic regime and at criticality, where they also play a central role for the breakdown of conformal invariance.

  17. Roles of long-range electrostatic domain interactions and K+ in phosphoenzyme transition of Ca2+-ATPase.

    PubMed

    Yamasaki, Kazuo; Daiho, Takashi; Danko, Stefania; Suzuki, Hiroshi

    2013-07-12

    Sarcoplasmic reticulum Ca(2+)-ATPase couples the motions and rearrangements of three cytoplasmic domains (A, P, and N) with Ca(2+) transport. We explored the role of electrostatic force in the domain dynamics in a rate-limiting phosphoenzyme (EP) transition by a systematic approach combining electrostatic screening with salts, computer analysis of electric fields in crystal structures, and mutations. Low KCl concentration activated and increasing salt above 0.1 m inhibited the EP transition. A plot of the logarithm of the transition rate versus the square of the mean activity coefficient of the protein gave a linear relationship allowing division of the activation energy into an electrostatic component and a non-electrostatic component in which the screenable electrostatic forces are shielded by salt. Results show that the structural change in the transition is sterically restricted, but that strong electrostatic forces, when K(+) is specifically bound at the P domain, come into play to accelerate the reaction. Electric field analysis revealed long-range electrostatic interactions between the N and P domains around their hinge. Mutations of the residues directly involved and other charged residues at the hinge disrupted in parallel the electric field and the structural transition. Favorable electrostatics evidently provides a low energy path for the critical N domain motion toward the P domain, overcoming steric restriction. The systematic approach employed here is, in general, a powerful tool for understanding the structural mechanisms of enzymes.

  18. The Central domain of RyR1 is the transducer for long-range allosteric gating of channel opening

    PubMed Central

    Bai, Xiao-Chen; Yan, Zhen; Wu, Jianping; Li, Zhangqiang; Yan, Nieng

    2016-01-01

    The ryanodine receptors (RyRs) are intracellular calcium channels responsible for rapid release of Ca2+ from the sarcoplasmic/endoplasmic reticulum (SR/ER) to the cytoplasm, which is essential for the excitation-contraction (E-C) coupling of cardiac and skeletal muscles. The near-atomic resolution structure of closed RyR1 revealed the molecular details of this colossal channel, while the long-range allosteric gating mechanism awaits elucidation. Here, we report the cryo-EM structures of rabbit RyR1 in three closed conformations at about 4 Å resolution and an open state at 5.7 Å. Comparison of the closed RyR1 structures shows a breathing motion of the cytoplasmic platform, while the channel domain and its contiguous Central domain remain nearly unchanged. Comparison of the open and closed structures shows a dilation of the S6 tetrahelical bundle at the cytoplasmic gate that leads to channel opening. During the pore opening, the cytoplasmic “O-ring” motif of the channel domain and the U-motif of the Central domain exhibit coupled motion, while the Central domain undergoes domain-wise displacement. These structural analyses provide important insight into the E-C coupling in skeletal muscles and identify the Central domain as the transducer that couples the conformational changes of the cytoplasmic platform to the gating of the central pore. PMID:27468892

  19. Long-range proton-coupled electron transfer in phenol-Ru(2,2'-bipyrazine)3(2+) dyads.

    PubMed

    Bronner, Catherine; Wenger, Oliver S

    2014-02-28

    Two dyads in which either 4-cyanophenol or un-substituted phenol is connected via a p-xylene spacer to a Ru(bpz)3(2+) (bpz = 2,2'-bipyrazine) complex were synthesized and investigated. Selective photo-excitation of Ru(bpz)3(2+) at 532 nm in a CH3CN-H2O mixture leads to the formation of 4-cyanophenolate or phenolate along with Ru(bpz)3(2+) in its electronic ground state. This apparent photoacid behavior can be understood on the basis of a reaction sequence comprised of an initial photoinduced proton-coupled electron transfer (PCET) during which 4-cyanophenol or phenol is oxidized and deprotonated, followed by a thermal electron transfer event in the course of which 4-cyanophenoxyl or phenoxyl is reduced by Ru(bpz)3(+) to 4-cyanophenolate or phenolate. Conceptually, this reaction sequence is identical to a sequence of photoinduced charge-separation and thermal charge-recombination events as observed previously for many electron transfer dyads, with the important difference that the initial photoinduced electron transfer process is proton-coupled. The dyad containing 4-cyanophenol reacts via concerted-proton electron transfer (CPET) whereas the dyad containing un-substituted phenol appears to react predominantly via a stepwise PCET mechanism. Long-range PCET is a key reaction in photosystem II. Understanding the factors that govern the kinetics of long-range PCET is desirable in the broader context of light-to-energy conversion by means of proton-electron separation across natural or artificial membranes.

  20. Form and function of long-range vocalizations in a Neotropical fossorial rodent: the Anillaco Tuco-Tuco (Ctenomys sp.).

    PubMed

    Amaya, Juan Pablo; Areta, Juan I; Valentinuzzi, Veronica S; Zufiaurre, Emmanuel

    2016-01-01

    The underground environment poses particular communication challenges for subterranean rodents. Some loud and low-pitched acoustic signals that can travel long distances are appropriate for long-range underground communication and have been suggested to be territorial signals. Long-range vocalizations (LRVs) are important in long-distance communication in Ctenomys tuco-tucos. We characterized the LRV of the Anillaco Tuco-Tuco (Ctenomys sp.) using recordings from free-living individuals and described the behavioral context in which this vocalization was produced during laboratory staged encounters between individuals of both sexes. Long-range calls of Anillaco tuco-tucos are low-frequency, broad-band, loud, and long sounds composed by the repetition of two syllable types: series (formed by notes and soft-notes) and individual notes. All vocalizations were initiated with series, but not all had individual notes. Males were heavier than females and gave significantly lower-pitched vocalizations, but acoustic features were independent of body mass in males. The pronounced variation among individuals in the arrangement and number of syllables and the existence of three types of series (dyads, triads, and tetrads), created a diverse collection of syntactic patterns in vocalizations that would provide the opportunity to encode multiple types of information. The existence of complex syntactic patterns and the description of soft-notes represent new aspects of the vocal communication of Ctenomys. Long-distance vocalizations by Anillaco Tuco-Tucos appear to be territorial signals used mostly in male-male interactions. First, emission of LRVs resulted in de-escalation or space-keeping in male-male and male-female encounters in laboratory experiments. Second, these vocalizations were produced most frequently (in the field and in the lab) by males in our study population. Third, males produced LRVs with greater frequency during male-male encounters compared to male

  1. Form and function of long-range vocalizations in a Neotropical fossorial rodent: the Anillaco Tuco-Tuco (Ctenomys sp.)

    PubMed Central

    Valentinuzzi, Veronica S.; Zufiaurre, Emmanuel

    2016-01-01

    The underground environment poses particular communication challenges for subterranean rodents. Some loud and low-pitched acoustic signals that can travel long distances are appropriate for long-range underground communication and have been suggested to be territorial signals. Long-range vocalizations (LRVs) are important in long-distance communication in Ctenomys tuco-tucos. We characterized the LRV of the Anillaco Tuco-Tuco (Ctenomys sp.) using recordings from free-living individuals and described the behavioral context in which this vocalization was produced during laboratory staged encounters between individuals of both sexes. Long-range calls of Anillaco tuco-tucos are low-frequency, broad-band, loud, and long sounds composed by the repetition of two syllable types: series (formed by notes and soft-notes) and individual notes. All vocalizations were initiated with series, but not all had individual notes. Males were heavier than females and gave significantly lower-pitched vocalizations, but acoustic features were independent of body mass in males. The pronounced variation among individuals in the arrangement and number of syllables and the existence of three types of series (dyads, triads, and tetrads), created a diverse collection of syntactic patterns in vocalizations that would provide the opportunity to encode multiple types of information. The existence of complex syntactic patterns and the description of soft-notes represent new aspects of the vocal communication of Ctenomys. Long-distance vocalizations by Anillaco Tuco-Tucos appear to be territorial signals used mostly in male-male interactions. First, emission of LRVs resulted in de-escalation or space-keeping in male-male and male-female encounters in laboratory experiments. Second, these vocalizations were produced most frequently (in the field and in the lab) by males in our study population. Third, males produced LRVs with greater frequency during male-male encounters compared to male

  2. Dynamic model for kinesin-mediated long-range transport and its local traffic jam caused by tau proteins

    NASA Astrophysics Data System (ADS)

    Nam, Woochul; Epureanu, Bogdan I.

    2017-01-01

    In neurons, several intracellular cargoes are transported by motor proteins (kinesins) which walk on microtubules (MTs). However, kinesins can possibly unbind from the MTs before they reach their destinations. The unbound kinesins randomly diffuse in neurons until they bind to MTs. Then, they walk again along the MTs to continue their tasks. Kinesins repeat this cycle of motion until they transport their cargoes to the destinations. However, most previous models mainly focused on the motion of kinesins when they walk on MTs. Thus, a new model is required to encompass the various types of kinesin motion. We developed a comprehensive model and studied the long-range axonal transport of neurons using the model. To enhance reliability of the model, it was constructed based on multiphysics on kinesin motion (i.e., chemical kinetics, diffusion, fluid dynamics, nonlinear dynamics, and stochastic characteristics). Also, parameter values for kinesin motions are carefully obtained by comparing the model predictions and several experimental observations. The axonal transport can be degraded when a large number of binding sites on MTs are blocked by excessive tau proteins. By considering the interference between walking kinesins and tau molecules on MTs, effects of tau proteins on the axonal transport are studied. One of the meaningful predictions obtained from the model is that the velocity is not an effective metric to estimate the degradation of the transport because the decrease in velocity is not noticeable when the concentration of tau protein is not high. However, our model shows that the transport locally changes near tau molecules on MTs even when the change in the velocity is not significant. Thus, a statistical method is proposed to detect this local change effectively. The advantage of this method is that a value obtained from this method is highly sensitive to the concentration of tau protein. Another benefit of this method is that this highly sensitive value can

  3. Dynamic model for kinesin-mediated long-range transport and its local traffic jam caused by tau proteins.

    PubMed

    Nam, Woochul; Epureanu, Bogdan I

    2017-01-01

    In neurons, several intracellular cargoes are transported by motor proteins (kinesins) which walk on microtubules (MTs). However, kinesins can possibly unbind from the MTs before they reach their destinations. The unbound kinesins randomly diffuse in neurons until they bind to MTs. Then, they walk again along the MTs to continue their tasks. Kinesins repeat this cycle of motion until they transport their cargoes to the destinations. However, most previous models mainly focused on the motion of kinesins when they walk on MTs. Thus, a new model is required to encompass the various types of kinesin motion. We developed a comprehensive model and studied the long-range axonal transport of neurons using the model. To enhance reliability of the model, it was constructed based on multiphysics on kinesin motion (i.e., chemical kinetics, diffusion, fluid dynamics, nonlinear dynamics, and stochastic characteristics). Also, parameter values for kinesin motions are carefully obtained by comparing the model predictions and several experimental observations. The axonal transport can be degraded when a large number of binding sites on MTs are blocked by excessive tau proteins. By considering the interference between walking kinesins and tau molecules on MTs, effects of tau proteins on the axonal transport are studied. One of the meaningful predictions obtained from the model is that the velocity is not an effective metric to estimate the degradation of the transport because the decrease in velocity is not noticeable when the concentration of tau protein is not high. However, our model shows that the transport locally changes near tau molecules on MTs even when the change in the velocity is not significant. Thus, a statistical method is proposed to detect this local change effectively. The advantage of this method is that a value obtained from this method is highly sensitive to the concentration of tau protein. Another benefit of this method is that this highly sensitive value can

  4. FY 1991--FY 1995 Information Technology Resources Long-Range Plan

    SciTech Connect

    Not Available

    1989-12-01

    The Department of Energy has consolidated its plans for Information Systems, Computing Resources, and Telecommunications into a single document, the Information Technology Resources Long-Range Plan. The consolidation was done as a joint effort by the Office of ADP Management and the Office of Computer Services and Telecommunications Management under the Deputy Assistant Secretary for Administration, Information, and Facilities Management. This Plan is the product of a long-range planning process used to project both future information technology requirements and the resources necessary to meet those requirements. It encompasses the plans of the various organizational components within the Department and its management and operating contractors over the next 5 fiscal years, 1991 through 1995.

  5. Fractal mechanisms and heart rate dynamics. Long-range correlations and their breakdown with disease

    NASA Technical Reports Server (NTRS)

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

    1995-01-01

    Under healthy conditions, the normal cardiac (sinus) interbeat interval fluctuates in a complex manner. Quantitative analysis using techniques adapted from statistical physics reveals the presence of long-range power-law correlations extending over thousands of heartbeats. This scale-invariant (fractal) behavior suggests that the regulatory system generating these fluctuations is operating far from equilibrium. In contrast, it is found that for subjects at high risk of sudden death (e.g., congestive heart failure patients), these long-range correlations break down. Application of fractal scaling analysis and related techniques provides new approaches to assessing cardiac risk and forecasting sudden cardiac death, as well as motivating development of novel physiologic models of systems that appear to be heterodynamic rather than homeostatic.

  6. Acoustically mediated long-range interaction among multiple spherical particles exposed to a plane standing wave

    NASA Astrophysics Data System (ADS)

    Zhang, Shenwei; Qiu, Chunyin; Wang, Mudi; Ke, Manzhu; Liu, Zhengyou

    2016-11-01

    In this work, we study the acoustically mediated interaction forces among multiple well-separated spherical particles trapped in the same node or antinode plane of a standing wave. An analytical expression of the acoustic interaction force is derived, which is accurate even for the particles beyond the Rayleigh limit. Interestingly, the multi-particle system can be decomposed into a series of independent two-particle systems described by pairwise interactions. Each pairwise interaction is a long-range interaction, as characterized by a soft oscillatory attenuation (at the power exponent of n = -1 or -2). The vector additivity of the acoustic interaction force, which is not well expected considering the nonlinear nature of the acoustic radiation force, is greatly useful for exploring a system consisting of a large number of particles. The capability of self-organizing a big particle cluster can be anticipated through such acoustically controllable long-range interaction.

  7. Spontaneous emission noise in long-range surface plasmon polariton waveguide based optical gyroscope.

    PubMed

    Wang, Yang-Yang; Zhang, Tong

    2014-09-19

    Spontaneous emission noise is an important limit to the performance of active plasmonic devices. Here, we investigate the spontaneous emission noise in the long-range surface plasmon-polariton waveguide based optical gyroscope. A theoretical model of the sensitivity is established to study the incoherent multi-beam interference of spontaneous emission in the gyroscope. Numerical results show that spontaneous emission produces a drift in the transmittance spectra and lowers the signal-to-noise-ratio of the gyroscope. It also strengthens the shot noise to be the main limit to the sensitivity of the gyroscope for high propagation loss. To reduce the negative effects of the spontaneous emission noise on the gyroscope, an external feedback loop is suggested to estimate the drift in the transmittance spectra and therefor enhance the sensitivity. Our work lays a foundation for the improvement of long-range surface plasmon-polariton gyroscope and paves the way to its practical application.

  8. Effects of competing short- and long-range dispersive interactions on discrete breathers.

    PubMed

    Kevrekidis, P G; Gaididei, Y B; Bishop, A R; Saxena, A

    2001-12-01

    The discrete nonlinear Schrödinger equation with competing short-range and long-range interactions is considered in spatial dimensions d> or =2. This model equation is derived for a situation of two linearly coupled excitations (independently of dimension), and we analytically and numerically study its properties in 2+1 dimensions. We analyze theoretically and demonstrate numerically the dependence of the discrete breather solutions on the amplitude and range of the interactions. We find that complete suppression of the existence thresholds obtained recently for short-range interactions can be achieved beyond a critical value of the amplitude or of the range of the long-range kernel. For supercritical values of the corresponding parameters, staggered branches of solutions are obtained both in theory as well as in the numerical experiment.

  9. Long-range protein–water dynamics in hyperactive insect antifreeze proteins

    PubMed Central

    Meister, Konrad; Ebbinghaus, Simon; Xu, Yao; Duman, John G.; DeVries, Arthur; Gruebele, Martin; Leitner, David M.; Havenith, Martina

    2013-01-01

    Antifreeze proteins (AFPs) are specific proteins that are able to lower the freezing point of aqueous solutions relative to the melting point. Hyperactive AFPs, identified in insects, have an especially high ability to depress the freezing point by far exceeding the abilities of other AFPs. In previous studies, we postulated that the activity of AFPs can be attributed to two distinct molecular mechanisms: (i) short-range direct interaction of the protein surface with the growing ice face and (ii) long-range interaction by protein-induced water dynamics extending up to 20 Å from the protein surface. In the present paper, we combine terahertz spectroscopy and molecular simulations to prove that long-range protein–water interactions make essential contributions to the high antifreeze activity of insect AFPs from the beetle Dendroides canadensis. We also support our hypothesis by studying the effect of the addition of the osmolyte sodium citrate. PMID:23277543

  10. Fractional quantum mechanics on networks: Long-range dynamics and quantum transport.

    PubMed

    Riascos, A P; Mateos, José L

    2015-11-01

    In this paper we study the quantum transport on networks with a temporal evolution governed by the fractional Schrödinger equation. We generalize the dynamics based on continuous-time quantum walks, with transitions to nearest neighbors on the network, to the fractional case that allows long-range displacements. By using the fractional Laplacian matrix of a network, we establish a formalism that combines a long-range dynamics with the quantum superposition of states; this general approach applies to any type of connected undirected networks, including regular, random, and complex networks, and can be implemented from the spectral properties of the Laplacian matrix. We study the fractional dynamics and its capacity to explore the network by means of the transition probability, the average probability of return, and global quantities that characterize the efficiency of this quantum process. As a particular case, we explore analytically these quantities for circulant networks such as rings, interacting cycles, and complete graphs.

  11. Mechanobiological induction of long-range contractility by diffusing biomolecules and size scaling in cell assemblies

    PubMed Central

    Dasbiswas, K.; Alster, E.; Safran, S. A.

    2016-01-01

    Mechanobiological studies of cell assemblies have generally focused on cells that are, in principle, identical. Here we predict theoretically the effect on cells in culture of locally introduced biochemical signals that diffuse and locally induce cytoskeletal contractility which is initially small. In steady-state, both the concentration profile of the signaling molecule as well as the contractility profile of the cell assembly are inhomogeneous, with a characteristic length that can be of the order of the system size. The long-range nature of this state originates in the elastic interactions of contractile cells (similar to long-range “macroscopic modes” in non-living elastic inclusions) and the non-linear diffusion of the signaling molecules, here termed mechanogens. We suggest model experiments on cell assemblies on substrates that can test the theory as a prelude to its applicability in embryo development where spatial gradients of morphogens initiate cellular development. PMID:27283037

  12. Evaluation of Long-Range Lightning Detection Networks Using TRMM/LIS Observations

    NASA Technical Reports Server (NTRS)

    Rudlosky, Scott D.; Holzworth, Robert H.; Carey, Lawrence D.; Schultz, Chris J.; Bateman, Monte; Cecil, Daniel J.; Cummins, Kenneth L.; Petersen, Walter A.; Blakeslee, Richard J.; Goodman, Steven J.

    2011-01-01

    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. Toward this end, the present study evaluates data from the World Wide Lightning Location Network (WWLLN) using observations from the Lightning Imaging Sensor (LIS) aboard the Tropical Rainfall Measurement Mission (TRMM) satellite. The study documents the WWLLN detection efficiency and location accuracy relative to LIS observations, describes the spatial variability in these performance metrics, and documents the characteristics of LIS flashes that are detected by WWLLN. Improved knowledge of the WWLLN detection capabilities 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).

  13. Spin Superfluidity and Long-Range Transport in Thin-Film Ferromagnets

    NASA Astrophysics Data System (ADS)

    Skarsvâg, Hans; Holmqvist, Cecilia; Brataas, Arne

    2015-12-01

    In ferromagnets, magnons may condense into a single quantum state. Analogous to superconductors, this quantum state may support transport without dissipation. Recent works suggest that longitudinal spin transport through a thin-film ferromagnet is an example of spin superfluidity. Although intriguing, this tantalizing picture ignores long-range dipole interactions; here, we demonstrate that such interactions dramatically affect spin transport. In single-film ferromagnets, "spin superfluidity" only exists at length scales (a few hundred nanometers in yttrium iron garnet) somewhat larger than the exchange length. Over longer distances, dipolar interactions destroy spin superfluidity. Nevertheless, we predict the reemergence of spin superfluidity in trilayer ferromagnet-normal metal-ferromagnet films that are ˜1 μ m in size. Such systems also exhibit other types of long-range spin transport in samples that are several micrometers in size.

  14. Spin superfluidity and long-range transport in thin-film ferromagnets

    NASA Astrophysics Data System (ADS)

    Skarsvåg, Hans; Holmqvist, Cecilia; Brataas, Arne

    In ferromagnets, magnons may condense into a single quantum state. Analogous to superconductors, this quantum state may support transport without dissipation. Recent works suggest that longitudinal spin transport through a thin-film ferromagnet is an example of spin superfluidity. Although intriguing, this tantalizing concept ignores long-range dipole interactions; here, we demonstrate that such interactions dramatically affect spin transport. In single-film ferromagnets, ''spin superfluidity'' only exists at length scales (a few hundred nanometers in yttrium iron garnet) somewhat larger than the exchange length. Over longer distances, dipolar interactions destroy spin superfluidity. Nevertheless, we predict the re-emergence of spin superfluidity in tri-layer ferromagnet-normal metal-ferromagnet films that are ~ 1 μ m in size. Such systems also exhibit other types of long-range spin transport in samples that are several micrometers in size.

  15. Spin Superfluidity and Long-Range Transport in Thin-Film Ferromagnets.

    PubMed

    Skarsvåg, Hans; Holmqvist, Cecilia; Brataas, Arne

    2015-12-04

    In ferromagnets, magnons may condense into a single quantum state. Analogous to superconductors, this quantum state may support transport without dissipation. Recent works suggest that longitudinal spin transport through a thin-film ferromagnet is an example of spin superfluidity. Although intriguing, this tantalizing picture ignores long-range dipole interactions; here, we demonstrate that such interactions dramatically affect spin transport. In single-film ferromagnets, "spin superfluidity" only exists at length scales (a few hundred nanometers in yttrium iron garnet) somewhat larger than the exchange length. Over longer distances, dipolar interactions destroy spin superfluidity. Nevertheless, we predict the reemergence of spin superfluidity in trilayer ferromagnet-normal metal-ferromagnet films that are ∼1  μm in size. Such systems also exhibit other types of long-range spin transport in samples that are several micrometers in size.

  16. Long-range transport and universality classes in in vitro viral infection spread

    NASA Astrophysics Data System (ADS)

    Manrubia, S. C.; García-Arriaza, J.; Domingo, E.; Escarmís, C.

    2006-05-01

    Dispersal mechanisms play a main role in the dynamics of infection spread. Recent experimental results with in vitro infections of foot-and-mouth disease virus reveal that the time needed for the virus to kill a cellular monolayer depends qualitatively on the number of viral particles required to initiate infection in a susceptible cell. A two-dimensional susceptible-infected-removed (SIR) model based on the experimental setting agrees with the observations only when viral particles are subject to long-range transport. Numerical and analytical results show that this long-range transport plays a role when a single particle causes infection, while it is inefficient when complementation between two or more particles is necessary.

  17. Note: long range and accurate measurement of deep trench microstructures by a specialized scanning tunneling microscope.

    PubMed

    Ju, Bing-Feng; Chen, Yuan-Liu; Zhang, Wei; Zhu, Wule; Jin, Chao; Fang, F Z

    2012-05-01

    A compact but practical scanning tunneling microscope (STM) with high aspect ratio and high depth capability has been specially developed. Long range scanning mechanism with tilt-adjustment stage is adopted for the purpose of adjusting the probe-sample relative angle to compensate the non-parallel effects. A periodical trench microstructure with a pitch of 10 μm has been successfully imaged with a long scanning range up to 2.0 mm. More innovatively, a deep trench with depth and step height of 23.0 μm has also been successfully measured, and slope angle of the sidewall can approximately achieve 67°. The probe can continuously climb the high step and exploring the trench bottom without tip crashing. The new STM could perform long range measurement for the deep trench and high step surfaces without image distortion. It enables accurate measurement and quality control of periodical trench microstructures.

  18. Anomalous diffusion and long-range correlations in the score evolution of the game of cricket

    NASA Astrophysics Data System (ADS)

    Ribeiro, Haroldo V.; Mukherjee, Satyam; Zeng, Xiao Han T.

    2012-08-01

    We investigate the time evolution of the scores of the second most popular sport in the world: the game of cricket. By analyzing, event by event, the scores of more than 2000 matches, we point out that the score dynamics is an anomalous diffusive process. Our analysis reveals that the variance of the process is described by a power-law dependence with a superdiffusive exponent, that the scores are statistically self-similar following a universal Gaussian distribution, and that there are long-range correlations in the score evolution. We employ a generalized Langevin equation with a power-law correlated noise that describes all the empirical findings very well. These observations suggest that competition among agents may be a mechanism leading to anomalous diffusion and long-range correlation.

  19. Absence of long-range chemical ordering in equimolar FeCoCrNi

    SciTech Connect

    Lucas, M. S.; Wilks, G. B.; Senkov, O. N.; Mauger, L.; Munoz, J. A.; Michel, E.; Horwath, J.; Semiatin, S. L.; Stone, M. B.; Abernathy, D. L.; Karapetrova, E.

    2012-06-18

    Equimolar FeCoCrNi alloys have been the topic of recent research as 'high-entropy alloys,' where the name is derived from the high configurational entropy of mixing for a random solid solution. Despite their name, no systematic study of ordering in this alloy system has been performed to date. Here, we present results from anomalous x-ray scattering and neutron scattering on quenched and annealed samples. An alloy of FeNi{sub 3} was prepared in the same manner to act as a control. Evidence of long-range chemical ordering is clearly observed in the annealed FeNi{sub 3} sample from both experimental techniques. The FeCoCrNi sample given the same heat treatment lacks long-range chemical order.

  20. Long-range visible light communication system based on LED collimating lens

    NASA Astrophysics Data System (ADS)

    Chen, Yingcong; Wen, Shangsheng; Wu, Yuxiang; Ren, Yuanyuan; Guan, Weipeng; Zhou, Yunlin

    2016-10-01

    An advanced visible light communication (VLC) system is proposed for long-range VLC, such as marine communication. The design of the system is conducted into two parts. Firstly, we design and optimize a collimating lens for the optical antenna by using Taguchi method. The lighting effects and optical power of the receiving end in different distances are simulated by TracePro software. Then, the long-range VLC channel is reconstructed by integrating the influence of the atmospheric attenuation and frequency response. The performance of the OOK coding VLC system is tested by Matlab software. The results show that: the emitting angle of the optimized collimating lens is 1.7°. By using 1 W LED and collimating lens as an optical antenna, the system can achieve a data rate of 210 Mbit/s at a bit error rate of 10-3 in 90 m.

  1. Information resources management long-range plan, FY1994--1998

    SciTech Connect

    Not Available

    1993-04-01

    This document describes IRM activities and the information technology resources and capabilities of the Department, the future requirements, and the strategies and plans to satisfy the identified requirements. The long-range planning process provides the systematic means to meet this objective and assists the Department in assuring that information technology (IT) support is provided in an efficient, effective, and timely manner so that its programmatic missions can be accomplished. Another important objective of the Plan is to promote better understanding, both within and external to the Department, of its IT environment, requirements, issues, and recommended solutions. This DOE IRM Plan takes into consideration the IRM requirements of approximately 50 different sites. The annual long-range planning cycle for supporting this Plan was initiated by a Call in August 1991 for site plans to be submitted in February 1992 by those Departmental components and contractors with major IRM requirements.

  2. The Effect of Long Range Order on Ionic Conductivity in a Solid Block Copolymer Electrolyte

    NASA Astrophysics Data System (ADS)

    Chintapalli, Mahati; Thelen, Jacob; Teran, Alexander; Balsara, Nitash

    2014-03-01

    Poly(styrene)-block-poly(ethylene oxide) (SEO) mixed with lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) salt is a promising material for battery electrolytes due to its high ionic conductivity and ability to suppress lithium dendrite growth. Ion conduction has been found to depend on many aspects of the electrolyte microstructure, including the morphology and degree of ordering. The effect of long range order on ionic conductivity was investigated in a lamellar SEO/LiTFSI mixture by in situ small angle x-ray scattering and ac impedance spectroscopy during polymer annealing. The observation that increasing long range order decreases ionic conductivity indicates that disorder, due to small grain size or defects, enhances the ionic conductivity of the electrolyte.

  3. Effect of long-range hopping and interactions on entanglement dynamics and many-body localization

    NASA Astrophysics Data System (ADS)

    Singh, Rajeev; Moessner, Roderich; Roy, Dibyendu

    2017-03-01

    We numerically investigate the dynamics of entanglement in a chain of spinless fermions with nonrandom but long-range hopping and interactions, and with random on-site energies. For moderate disorder in the absence of interactions, the chain hosts delocalized states at the top of the band which undergo a delocalization-localization transition with increasing disorder. We find an interesting regime in this noninteracting disordered chain where the long-time entanglement entropy scales as S (t )˜lnt and the saturated entanglement entropy scales with system size L as S (L ,t →∞ )˜lnL . We further study the interplay of long-range hopping and interactions on the growth of entanglement and the many-body localization (MBL) transition in this system. We develop an analogy to higher-dimensional short-range systems to compare and contrast such behavior with the physics of MBL in a higher dimension.

  4. Dark matter, long-range forces, and large-scale structure

    NASA Technical Reports Server (NTRS)

    Gradwohl, Ben-Ami; Frieman, Joshua A.

    1992-01-01

    If the dark matter in galaxies and clusters is nonbaryonic, it can interact with additional long-range fields that are invisible to experimental tests of the equivalence principle. We discuss the astrophysical and cosmological implications of a long-range force coupled only to the dark matter and find rather tight constraints on its strength. If the force is repulsive (attractive), the masses of galaxy groups and clusters (and the mean density of the universe inferred from them) have been systematically underestimated (overestimated). We explore the consequent effects on the two-point correlation function, large-scale velocity flows, and microwave background anisotropies, for models with initial scale-invariant adiabatic perturbations and cold dark matter.

  5. Fractional quantum mechanics on networks: Long-range dynamics and quantum transport

    NASA Astrophysics Data System (ADS)

    Riascos, A. P.; Mateos, José L.

    2015-11-01

    In this paper we study the quantum transport on networks with a temporal evolution governed by the fractional Schrödinger equation. We generalize the dynamics based on continuous-time quantum walks, with transitions to nearest neighbors on the network, to the fractional case that allows long-range displacements. By using the fractional Laplacian matrix of a network, we establish a formalism that combines a long-range dynamics with the quantum superposition of states; this general approach applies to any type of connected undirected networks, including regular, random, and complex networks, and can be implemented from the spectral properties of the Laplacian matrix. We study the fractional dynamics and its capacity to explore the network by means of the transition probability, the average probability of return, and global quantities that characterize the efficiency of this quantum process. As a particular case, we explore analytically these quantities for circulant networks such as rings, interacting cycles, and complete graphs.

  6. Stable distribution and long-range correlation of Brent crude oil market

    NASA Astrophysics Data System (ADS)

    Yuan, Ying; Zhuang, Xin-tian; Jin, Xiu; Huang, Wei-qiang

    2014-11-01

    An empirical study of stable distribution and long-range correlation in Brent crude oil market was presented. First, it is found that the empirical distribution of Brent crude oil returns can be fitted well by a stable distribution, which is significantly different from a normal distribution. Second, the detrended fluctuation analysis for the Brent crude oil returns shows that there are long-range correlation in returns. It implies that there are patterns or trends in returns that persist over time. Third, the detrended fluctuation analysis for the Brent crude oil returns shows that after the financial crisis 2008, the Brent crude oil market becomes more persistence. It implies that the financial crisis 2008 could increase the frequency and strength of the interdependence and correlations between the financial time series. All of these findings may be used to improve the current fractal theories.

  7. The callipyge mutation enhances bidirectional long-range DLK1-GTL2 intergenic transcription in cis

    PubMed Central

    Takeda, Haruko; Caiment, Florian; Smit, Maria; Hiard, Samuel; Tordoir, Xavier; Cockett, Noelle; Georges, Michel; Charlier, Carole

    2006-01-01

    The callipyge mutation (CLPG) is an A to G transition that affects a muscle-specific long-range control element located in the middle of the 90-kb DLK1-GTL2 intergenic (IG) region. It causes ectopic expression of a 327-kb cluster of imprinted genes in skeletal muscle, resulting in the callipyge muscular hypertrophy and its non-Mendelian inheritance pattern known as polar overdominance. We herein demonstrate that the CLPG mutation alters the muscular epigenotype of the DLK1-GTL2 IG region in cis, including hypomethylation, acquisition of novel DNase-I hypersentivite sites, and, most strikingly, strongly enhanced bidirectional, long-range IG transcription. The callipyge phenotype thus emerges as a unique model to study the functional significance of IG transcription, which recently has proven to be a widespread, yet elusive, feature of the mammalian genome. PMID:16690740

  8. Enzymatic cellulose oxidation is linked to lignin by long-range electron transfer

    PubMed Central

    Westereng, Bjørge; Cannella, David; Wittrup Agger, Jane; Jørgensen, Henning; Larsen Andersen, Mogens; Eijsink, Vincent G.H.; Felby, Claus

    2015-01-01

    Enzymatic oxidation of cell wall polysaccharides by lytic polysaccharide monooxygenases (LPMOs) plays a pivotal role in the degradation of plant biomass. While experiments have shown that LPMOs are copper dependent enzymes requiring an electron donor, the mechanism and origin of the electron supply in biological systems are only partly understood. We show here that insoluble high molecular weight lignin functions as a reservoir of electrons facilitating LPMO activity. The electrons are donated to the enzyme by long-range electron transfer involving soluble low molecular weight lignins present in plant cell walls. Electron transfer was confirmed by electron paramagnetic resonance spectroscopy showing that LPMO activity on cellulose changes the level of unpaired electrons in the lignin. The discovery of a long-range electron transfer mechanism links the biodegradation of cellulose and lignin and sheds new light on how oxidative enzymes present in plant degraders may act in concert. PMID:26686263

  9. Mechanobiological induction of long-range contractility by diffusing biomolecules and size scaling in cell assemblies

    NASA Astrophysics Data System (ADS)

    Dasbiswas, K.; Alster, E.; Safran, S. A.

    2016-06-01

    Mechanobiological studies of cell assemblies have generally focused on cells that are, in principle, identical. Here we predict theoretically the effect on cells in culture of locally introduced biochemical signals that diffuse and locally induce cytoskeletal contractility which is initially small. In steady-state, both the concentration profile of the signaling molecule as well as the contractility profile of the cell assembly are inhomogeneous, with a characteristic length that can be of the order of the system size. The long-range nature of this state originates in the elastic interactions of contractile cells (similar to long-range “macroscopic modes” in non-living elastic inclusions) and the non-linear diffusion of the signaling molecules, here termed mechanogens. We suggest model experiments on cell assemblies on substrates that can test the theory as a prelude to its applicability in embryo development where spatial gradients of morphogens initiate cellular development.

  10. Photoassociation of a cold-atom-molecule pair: Long-range quadrupole-quadrupole interactions

    SciTech Connect

    Lepers, M.; Dulieu, O.; Kokoouline, V.

    2010-10-15

    The general formalism of the multipolar expansion of electrostatic interactions is applied to the calculation of the potential energy between an excited atom (without fine structure) and a ground-state diatomic molecule at large mutual separations. Both partners exhibit a permanent quadrupole moment so that their mutual long-range interaction is dominated by a quadrupole-quadrupole term, which is attractive enough to bind trimers. Numerical results are given for an excited Cs(6{sup 2}P) atom and a ground-state Cs{sub 2} molecule. The prospects for achieving photoassociation of a cold-atom-dimer pair are thus discussed and found promising. The formalism can be generalized to the long-range interaction between molecules to investigate the formation of cold tetramers.

  11. Excitation of Ultracold Molecules to ``TRILOBITE-LIKE" Long-Range Molecular Rydberg States

    NASA Astrophysics Data System (ADS)

    Bellos, M. A.; Carollo, R.; Banerjee, J.; Eyler, E. E.; Gould, P. L.; Stwalley, W. C.

    2013-06-01

    A class of long-range Rydberg molecules, sometimes called ``trilobite states", occurs when a ground-state atom is embedded in the electronic cloud of a Rydberg atom. The bond between the Rydberg atom and the ground-state atom originates from the low-energy scattering of the Rydberg electron from the ground-state atom. We produce trilobite-like states of ultracold Rb_2 at low principal quantum numbers and at internuclear separations less than 40 bohr. We populate these states through single-photon ultraviolet transitions starting from molecules in high-lying vibrational levels of the lowest triplet state. This demonstrates that long-range Rydberg molecules can also be excited through bound-bound transitions, in addition to previous studies that used free-bound transitions. We also discuss the advantages of a bound-bound pathway. C. H. Greene, A. S. Dickinson, and H. R. Sadeghpour, Phys. Rev. Lett. 85, 2458 (2000).

  12. Many-body localization in a long range XXZ model with random-field

    NASA Astrophysics Data System (ADS)

    Li, Bo

    2016-12-01

    Many-body localization (MBL) in a long range interaction XXZ model with random field are investigated. Using the exact diagonal method, the MBL phase diagram with different tuning parameters and interaction range is obtained. It is found that the phase diagram of finite size results supplies strong evidence to confirm that the threshold interaction exponent α = 2. The tuning parameter Δ can efficiently change the MBL edge in high energy density stats, thus the system can be controlled to transfer from thermal phase to MBL phase by changing Δ. The energy level statistics data are consistent with result of the MBL phase diagram. However energy level statistics data cannot detect the thermal phase correctly in extreme long range case.

  13. Noise-induced dynamical phase transitions in long-range systems.

    PubMed

    Chavanis, Pierre-Henri; Baldovin, Fulvio; Orlandini, Enzo

    2011-04-01

    In the thermodynamic limit, the time evolution of isolated long-range interacting systems is properly described by the Vlasov equation. This equation admits nonequilibrium dynamically stable stationary solutions characterized by a zero order parameter. We show that the presence of external noise sources, such as a heat bath, can reduce their lifetime and induce at a specific time a dynamical phase transition marked by a nonzero order parameter. This transition may be used as a distinctive experimental signature of the temporary existence of nonequilibrium Vlasov-stable states. In particular, we present evidence of a regime characterized by an order parameter pulse. Our analytical results are corroborated by numerical simulations of a paradigmatic long-range model.

  14. Long-range effect in nitrogen ion-implanted AISI 316L stainless steel

    NASA Astrophysics Data System (ADS)

    Budzynski, P.

    2015-01-01

    The effect of nitrogen ion implantation on AISI 316L stainless steel was investigated. The microstructure and composition of an N implanted layer were studied by RBS, GIXRD, SEM, and EDX measurements. Friction and wear tests were also performed. The discrepancy between the measured and calculated stopped ion maximum range does not exceed 0.03 μm. After nitrogen implantation with a fluence of 5 × 1017 ion/cm2, additional phases of expanded austenite were detected. At a 5-fold larger depth than the maximum ion range, improvement in the coefficient of friction and wear was detected. We have shown, for the first time, the long-range effect in tribological investigations. The long-range effect is caused by movement of not only defects along the depth of the sample, as assumed so far, but also nitrogen atoms.

  15. A formalism for studying long-range correlations in many-alphabets sequences

    NASA Astrophysics Data System (ADS)

    Narasimhan, S. L.; Nathan, Joseph A.; Krishna, P. S. R.; Murthy, K. P. N.

    2006-07-01

    We formulate a mean-field-like theory of long-range correlated L-alphabets sequences, which are actually systems with (L-1) independent parameters. Depending on the values of these parameters, the variance on the average number of any given symbol in the sequence shows a linear or a superlinear dependence on the total length of the sequence. We present exact solution to the four-alphabets and three-alphabets sequences. We also demonstrate that a mapping of the given sequence into a smaller alphabets sequence (namely, a coarse-graining process) does not necessarily imply that long-range correlations found in the latter would correspond to those of the former.

  16. Enzymatic cellulose oxidation is linked to lignin by long-range electron transfer.

    PubMed

    Westereng, Bjørge; Cannella, David; Wittrup Agger, Jane; Jørgensen, Henning; Larsen Andersen, Mogens; Eijsink, Vincent G H; Felby, Claus

    2015-12-21

    Enzymatic oxidation of cell wall polysaccharides by lytic polysaccharide monooxygenases (LPMOs) plays a pivotal role in the degradation of plant biomass. While experiments have shown that LPMOs are copper dependent enzymes requiring an electron donor, the mechanism and origin of the electron supply in biological systems are only partly understood. We show here that insoluble high molecular weight lignin functions as a reservoir of electrons facilitating LPMO activity. The electrons are donated to the enzyme by long-range electron transfer involving soluble low molecular weight lignins present in plant cell walls. Electron transfer was confirmed by electron paramagnetic resonance spectroscopy showing that LPMO activity on cellulose changes the level of unpaired electrons in the lignin. The discovery of a long-range electron transfer mechanism links the biodegradation of cellulose and lignin and sheds new light on how oxidative enzymes present in plant degraders may act in concert.

  17. Long-range wakefields and split-tune lattice at the SLC

    SciTech Connect

    Decker, F.J.; Adolphsen, C.E.; Assmann, R.

    1996-08-01

    At the SLC, a train consisting of one positron bunch followed by two electron bunches is accelerated in the linac, each separated by about 60 ns. Long-range transverse wakefields from the leading bunch were found to cause up to a factor of three increase in beam jitter for the trailing bunches. Incoming jitter is efficiently damped by BNS damping, but excitations in the middle of the linac from sources such as long-range wakefields can grow in amplitude. To measure the wake function, the time difference between the positron and electron bunches was changed, determining the frequency and strength of the dominant mode contributing to the dipole Wakefield. By splitting the horizontal and vertical phase advance, or {open_quote}tune{close_quote}, of the magnetic lattice, it was possible to decrease the resonant excitation from these wakefields and thereby reduce the jitter of the electron beam by a factor of two.

  18. Long-range protein-water dynamics in hyperactive insect antifreeze proteins.

    PubMed

    Meister, Konrad; Ebbinghaus, Simon; Xu, Yao; Duman, John G; DeVries, Arthur; Gruebele, Martin; Leitner, David M; Havenith, Martina

    2013-01-29

    Antifreeze proteins (AFPs) are specific proteins that are able to lower the freezing point of aqueous solutions relative to the melting point. Hyperactive AFPs, identified in insects, have an especially high ability to depress the freezing point by far exceeding the abilities of other AFPs. In previous studies, we postulated that the activity of AFPs can be attributed to two distinct molecular mechanisms: (i) short-range direct interaction of the protein surface with the growing ice face and (ii) long-range interaction by protein-induced water dynamics extending up to 20 Å from the protein surface. In the present paper, we combine terahertz spectroscopy and molecular simulations to prove that long-range protein-water interactions make essential contributions to the high antifreeze activity of insect AFPs from the beetle Dendroides canadensis. We also support our hypothesis by studying the effect of the addition of the osmolyte sodium citrate.

  19. Spontaneous emission noise in long-range surface plasmon polariton waveguide based optical gyroscope

    PubMed Central

    Wang, Yang-Yang; Zhang, Tong

    2014-01-01

    Spontaneous emission noise is an important limit to the performance of active plasmonic devices. Here, we investigate the spontaneous emission noise in the long-range surface plasmon-polariton waveguide based optical gyroscope. A theoretical model of the sensitivity is established to study the incoherent multi-beam interference of spontaneous emission in the gyroscope. Numerical results show that spontaneous emission produces a drift in the transmittance spectra and lowers the signal-to-noise-ratio of the gyroscope. It also strengthens the shot noise to be the main limit to the sensitivity of the gyroscope for high propagation loss. To reduce the negative effects of the spontaneous emission noise on the gyroscope, an external feedback loop is suggested to estimate the drift in the transmittance spectra and therefor enhance the sensitivity. Our work lays a foundation for the improvement of long-range surface plasmon-polariton gyroscope and paves the way to its practical application. PMID:25234712

  20. UMER: An analog computer for dynamics of swarms interacting via long-range forces

    NASA Astrophysics Data System (ADS)

    Kishek, R. A.; Bai, G.; Bernal, S.; Feldman, D.; Godlove, T. F.; Haber, I.; O'Shea, P. G.; Quinn, B.; Papadopoulos, C.; Reiser, M.; Stratakis, D.; Tian, K.; Tobin, C. J.; Walter, M.

    2006-06-01

    Some of the most challenging and interesting problems in nature involve large numbers of objects or particles mutually interacting through long-range forces. Examples range from galaxies and plasmas to flocks of birds and traffic flow on a highway. Even in cases where the form of the interacting force is precisely known, such as the 1/ r2-dependent Coulomb and gravitational forces, such problems present a formidable theoretical and modeling challenge for large numbers of interacting bodies. This paper reports on a newly constructed, scaled particle accelerator that will serve as an experimental testbed for the dynamics of swarms interacting through long-range forces. Primarily designed for intense beam dynamics studies for advanced accelerators, the University of Maryland Electron Ring (UMER) design is described in detail and an update on commissioning is provided. An example application to a system other than a charged particle beam is discussed.

  1. Low-frequency source for very long-range underwater communication.

    PubMed

    Mosca, Frédéric; Matte, Guillaume; Shimura, Takuya

    2013-01-01

    Very long-range underwater acoustic communication (UAC) is crucial for long cruising (>1000 km) autonomous underwater vehicles (AUVs). Very long-range UAC source for AUV must exhibit high electro-acoustic efficiency (>60%) and compactness. This paper describes the Janus-Hammer Bell (JHB) transducer that has been designed for this purpose and meets those requirements. The transducer works on the 450-550 Hz bandwidth and reaches source level above 200 dB (ref. 1 μPa at 1 m) with 1 kW excitation and full immersion capability. JHB source has been used for communication experiments by the Japanese institute for marine technology (Japan Agency for Marine-Earth Science and Technology) achieving a baud rate of 100 bits/s at 1000 km.

  2. Distortion-triggered loss of long-range order in solids with bonding energy hierarchy.

    PubMed

    Kolobov, A V; Krbal, M; Fons, P; Tominaga, J; Uruga, T

    2011-04-01

    An amorphous-to-crystal transition in phase-change materials like Ge-Sb-Te is widely used for data storage. The basic principle is to take advantage of the property contrast between the crystalline and amorphous states to encode information; amorphization is believed to be caused by melting the materials with an intense laser or electrical pulse and subsequently quenching the melt. Here, we demonstrate that distortions in the crystalline phase may trigger a collapse of long-range order, generating the amorphous phase without going through the liquid state. We further show that the principal change in optical properties occurs during the distortion of the still crystalline structure, upsetting yet another commonly held belief that attributes the change in properties to the loss of long-range order. Furthermore, our results suggest a way to lower energy consumption by condensing phase change inducing energy into shorter pulses or through the use of coherent phonon excitation.

  3. Measurements of long-range correlations and bicoherence during biasing in HSX

    NASA Astrophysics Data System (ADS)

    Wilcox, Robert; van Milligen, Boudewijn; Pedrosa, Maria Angeles; Ramisch, Mirko; Anderson, David

    2010-11-01

    Using toroidally-spaced Langmuir probes, long-range fluctuation correlations have been measured in floating potential signals during biased discharges in the HSX stellarator. The increase in long-range correlations during biasing occurs in the floating potential signals, but not in the ion saturation current signals. This has been linked to zonal flow formation in the TJ-II stellarator, both in biased discharges and in naturally occurring improved-confinement discharges [1]. Measurements of the auto-bicoherence of the poloidal electric field signals show an increase in broadband 3-wave coupling during biasing, which is analyzed and compared to both biased and naturally occurring enhanced-confinement discharges in TJ-II [2]. Additional measurements of fluctuation moments in HSX are also presented.[4pt] [1] M.A. Pedrosa, et al, Phys. Rev. Lett. 100 (2008) 215003.[0pt] [2] B.Ph. van Milligen, et al, Nucl. Fusion 48 (2008) 115003

  4. Impact of Local Pollution Versus Long Range Transported Aerosols on Clouds and Precipitation over California

    NASA Astrophysics Data System (ADS)

    Prather, K. A.

    2015-12-01

    Aerosols form cloud droplets and ice crystals in clouds and can profoundly impact precipitation processes. In-situ aircraft measurements of the composition of individual cloud residuals have been used to study the impact of different aerosol sources including sea spray, dust, soot, and biomass burning on cloud microphysics and precipitation processes. Aircraft studies in 2011 as part of the CalWater project showed that long range transport of dust aerosols from as far away as Africa and biological particles can lead to an increase in the amount of snowfall over California. This presentation will describe results from CalWater-2015 involving aircraft and ground-based measurements at a coastal site. A discussion of the aerosol sources measured in clouds will be presented detailing the relative impacts of local versus long range transported pollution aerosols over California.

  5. Entropy and long-range memory in random symbolic additive Markov chains

    NASA Astrophysics Data System (ADS)

    Melnik, S. S.; Usatenko, O. V.

    2016-06-01

    The goal of this paper is to develop an estimate for the entropy of random symbolic sequences with elements belonging to a finite alphabet. As a plausible model, we use the high-order additive stationary ergodic Markov chain with long-range memory. Supposing that the correlations between random elements of the chain are weak, we express the conditional entropy of the sequence by means of the symbolic pair correlation function. We also examine an algorithm for estimating the conditional entropy of finite symbolic sequences. We show that the entropy contains two contributions, i.e., the correlation and the fluctuation. The obtained analytical results are used for numerical evaluation of the entropy of written English texts and DNA nucleotide sequences. The developed theory opens the way for constructing a more consistent and sophisticated approach to describe the systems with strong short-range and weak long-range memory.

  6. Long-range repulsion of colloids driven by ion exchange and diffusiophoresis.

    PubMed

    Florea, Daniel; Musa, Sami; Huyghe, Jacques M R; Wyss, Hans M

    2014-05-06

    Interactions between surfaces and particles in aqueous suspension are usually limited to distances smaller than 1 μm. However, in a range of studies from different disciplines, repulsion of particles has been observed over distances of up to hundreds of micrometers, in the absence of any additional external fields. Although a range of hypotheses have been suggested to account for such behavior, the physical mechanisms responsible for the phenomenon still remain unclear. To identify and isolate these mechanisms, we perform detailed experiments on a well-defined experimental system, using a setup that minimizes the effects of gravity and convection. Our experiments clearly indicate that the observed long-range repulsion is driven by a combination of ion exchange, ion diffusion, and diffusiophoresis. We develop a simple model that accounts for our data; this description is expected to be directly applicable to a wide range of systems exhibiting similar long-range forces.

  7. Short-range/Long-range Integrated Target (SLIT) for Video Guidance Sensor Rendezvous and Docking

    NASA Technical Reports Server (NTRS)

    Roe, Fred D. (Inventor); Bryan, Thomas C. (Inventor)

    2009-01-01

    A laser target reflector assembly for mounting upon spacecraft having a long-range reflector array formed from a plurality of unfiltered light reflectors embedded in an array pattern upon a hemispherical reflector disposed upon a mounting plate. The reflector assembly also includes a short-range reflector array positioned upon the mounting body proximate to the long-range reflector array. The short-range reflector array includes three filtered light reflectors positioned upon extensions from the mounting body. The three filtered light reflectors retro-reflect substantially all incident light rays that are transmissive by their monochromatic filters and received by the three filtered light reflectors. In one embodiment the short-range reflector array is embedded within the hemispherical reflector,

  8. Imaging vs. non-imaging in long range neutron detection scenarios.

    SciTech Connect

    Greenberg, Charles; Mascarenhas, Nicholas; Vaughn, Andrew C.; Marleau, Peter

    2008-10-01

    Standoff neutron detection technology has advanced in recent years, primarily for counterterrorism applications. Sandia National Laboratories has developed the Neutron Scatter Camera -- a fast neutron imaging system using liquid scintillator with potential applications in long range neutron detection. This talk will explore the pros, cons and practical uses of the Neutron Scatter Camera versus more traditional neutron detectors such as He-3 proportional counters. Several applications for neutron detection and imaging will be explored. We will perform predictive calculations of the response of the Neutron Scatter Camera and traditional He-3 detectors. The applications range from counterterrorism to arms control to safeguards. We will discuss future evolution of the scatter camera to enhance long range detection.

  9. A new smoothing function to introduce long-range electrostatic effects in QM/MM calculations

    SciTech Connect

    Fang, Dong; Duke, Robert E.; Andrés Cisneros, G.

    2015-07-28

    A new method to account for long range electrostatic contributions is proposed and implemented for quantum mechanics/molecular mechanics long range electrostatic correction (QM/MM-LREC) calculations. This method involves the use of the minimum image convention under periodic boundary conditions and a new smoothing function for energies and forces at the cutoff boundary for the Coulomb interactions. Compared to conventional QM/MM calculations without long-range electrostatic corrections, the new method effectively includes effects on the MM environment in the primary image from its replicas in the neighborhood. QM/MM-LREC offers three useful features including the avoidance of calculations in reciprocal space (k-space), with the concomitant avoidance of having to reproduce (analytically or approximately) the QM charge density in k-space, and the straightforward availability of analytical Hessians. The new method is tested and compared with results from smooth particle mesh Ewald (PME) for three systems including a box of neat water, a double proton transfer reaction, and the geometry optimization of the critical point structures for the rate limiting step of the DNA dealkylase AlkB. As with other smoothing or shifting functions, relatively large cutoffs are necessary to achieve comparable accuracy with PME. For the double-proton transfer reaction, the use of a 22 Å cutoff shows a close reaction energy profile and geometries of stationary structures with QM/MM-LREC compared to conventional QM/MM with no truncation. Geometry optimization of stationary structures for the hydrogen abstraction step by AlkB shows some differences between QM/MM-LREC and the conventional QM/MM. These differences underscore the necessity of the inclusion of the long-range electrostatic contribution.

  10. Operation of long-range substituent effects in rigid opiates: protonated and unprotonated oxymorphone

    SciTech Connect

    Darling, S.D.; Kolb, V.M.; Mandel, G.S.; Mandel, N.S.

    1982-07-01

    The structure of protonated oxymorphone (amine salt) was determined by an X-ray crystallographic study. Significant differences were found with the previously determined structure of unprotonated oxymorphone (free base). Upon protonation on nitrogen, an elongation of the N-C bound occurred, accompanied by subtle changes in bond lengths and angles distant from the site of protonation. These changes in geometry are interpreted as a reflection of long-range substituent effects.

  11. Simple model for active nematics: quasi-long-range order and giant fluctuations.

    PubMed

    Chaté, Hugues; Ginelli, Francesco; Montagne, Raúl

    2006-05-12

    We propose a simple microscopic model for active nematic particles similar in spirit to the Vicsek model for self-propelled polar particles. In two dimensions, we show that this model exhibits a Kosterlitz-Thouless-like transition to quasi-long-range orientational order and that in this nonequilibrium context, the ordered phase is characterized by giant density fluctuations, in agreement with the predictions of Ramaswamy et al.

  12. [Long-range electron transfer in globular proteins by polaron excitation].

    PubMed

    Lakhno, V L; Chuev, G N

    1997-01-01

    Considering polaron model, we have calculated an electron state localized in the protein heme. Using these calculations: the electron density and electron energy, we estimated the self-exchange rate constant for cyt c (horse heart), its reorganization energy, matrix element, and dependence of this rate on the distance between hemes. The results are compared with the experimental data and other theoretical estimations. We discuss the role of polaron excitations in the long-range electron transfer in globular proteins.

  13. Studies for determining the optimum propulsion system characteristics for use in a long range transport aircraft

    NASA Technical Reports Server (NTRS)

    Brines, G. L.

    1972-01-01

    A comprehensive evaluation of propulsion systems for the next generation of near-sonic long range transport aircraft indicates that socially responsive noise and emission goals can be achieved within the probable limits of acceptable airplane performance and economics. Technology advances needed in the 1975-1985 time period to support the development of these propulsion systems are identified and discussed. The single most significant result is the low noise, high performance potential of a low tip speed, spaced, two-stage fan.

  14. Peroxy radicals and ozone photochemistry in air masses undergoing long-range transport

    NASA Astrophysics Data System (ADS)

    Parker, A. E.; Monks, P. S.; Jacob, M. J.; Penkett, S. A.; Lewis, A. C.; Stewart, D. J.; Whalley, L. K.; Methven, J.; Stohl, A.

    2009-09-01

    Concentrations of peroxy radicals (HO2+ΣiRiO2) in addition to other trace gases were measured onboard the UK Meteorological Office/Natural Environment Research Council British Aerospace 146-300 atmospheric research aircraft during the Intercontinental Transport of Ozone and Precursors (ITOP) campaign based at Horta Airport, Faial, Azores (38.58° N, 28.72° W) in July/August 2004. The overall peroxy radical altitude profile displays an increase with altitude that is likely to have been impacted by the effects of long-range transport. The peroxy radical altitude profile for air classified as of marine origin shows no discernable altitude profile. A range of air-masses were intercepted with varying source signatures, including those with aged American and Asian signatures, air-masses of biomass burning origin, and those that originated from the east coast of the United States. Enhanced peroxy radical concentrations have been observed within this range of air-masses indicating that long-range transported air-masses traversing the Atlantic show significant photochemical activity. The net ozone production at clear sky limit is in general negative, and as such the summer mid-Atlantic troposphere is at limit net ozone destructive. However, there is clear evidence of positive ozone production even at clear sky limit within air masses undergoing long-range transport, and during ITOP especially between 5 and 5.5 km, which in the main corresponds to a flight that extensively sampled air with a biomass burning signature. Ozone production was NOx limited throughout ITOP, as evidenced by a good correlation (r2=0.72) between P(O3) and NO. Strong positive net ozone production has also been seen in varying source signature air-masses undergoing long-range transport, including but not limited to low-level export events, and export from the east coast of the United States.

  15. Development of a Long-Range Gliding Underwater Vehicle Utilizing Java Sun SPOT Technology

    DTIC Science & Technology

    2008-09-01

    solution to support those objectives. Hardware-in-the-loop simulation and testing of embedded systems is a proven method for effectively testing...planning and simulation tool, combined with an improved low-cost embedded-system robot controller, to test and evaluate a new free-flood, long-range... SIMULATION (MOVES) from the NAVAL POSTGRADUATE SCHOOL September 2008 Author: Ronald J. Hemmelgarn Approved by: Don Brutzman, Ph.D

  16. Time series analysis and long range correlations of Nordic spot electricity market data

    NASA Astrophysics Data System (ADS)

    Erzgräber, Hartmut; Strozzi, Fernanda; Zaldívar, José-Manuel; Touchette, Hugo; Gutiérrez, Eugénio; Arrowsmith, David K.

    2008-11-01

    The electricity system price of the Nord Pool spot market is analysed. Different time scale analysis tools are assessed with focus on the Hurst exponent and long range correlations. Daily and weekly periodicities of the spot market are identified. Even though space time separation plots suggest more stationary behaviour than other financial time series, we find large fluctuations of the spot price market which suggest time-dependent scaling parameters.

  17. A convection-driven long-range linear gradient generator with dynamic control.

    PubMed

    Wang, Hao; Chen, Chia-Hung; Xiang, Zhuolin; Wang, Ming; Lee, Chengkuo

    2015-03-21

    We developed a novel gradient generator to achieve long range and linear chemical gradients with a dynamic control function. The length of the gradient can be on the centimetre scale. The gradient profile can be tuned by changing the flow rates. The device can work in both high flow rate regimes with large shear stress and low flow rate regimes with minimum shear stress. The drug screening function was demonstrated by the viability test of PC-9 cancer cells.

  18. A new smoothing function to introduce long-range electrostatic effects in QM/MM calculations.

    PubMed

    Fang, Dong; Duke, Robert E; Cisneros, G Andrés

    2015-07-28

    A new method to account for long range electrostatic contributions is proposed and implemented for quantum mechanics/molecular mechanics long range electrostatic correction (QM/MM-LREC) calculations. This method involves the use of the minimum image convention under periodic boundary conditions and a new smoothing function for energies and forces at the cutoff boundary for the Coulomb interactions. Compared to conventional QM/MM calculations without long-range electrostatic corrections, the new method effectively includes effects on the MM environment in the primary image from its replicas in the neighborhood. QM/MM-LREC offers three useful features including the avoidance of calculations in reciprocal space (k-space), with the concomitant avoidance of having to reproduce (analytically or approximately) the QM charge density in k-space, and the straightforward availability of analytical Hessians. The new method is tested and compared with results from smooth particle mesh Ewald (PME) for three systems including a box of neat water, a double proton transfer reaction, and the geometry optimization of the critical point structures for the rate limiting step of the DNA dealkylase AlkB. As with other smoothing or shifting functions, relatively large cutoffs are necessary to achieve comparable accuracy with PME. For the double-proton transfer reaction, the use of a 22 Å cutoff shows a close reaction energy profile and geometries of stationary structures with QM/MM-LREC compared to conventional QM/MM with no truncation. Geometry optimization of stationary structures for the hydrogen abstraction step by AlkB shows some differences between QM/MM-LREC and the conventional QM/MM. These differences underscore the necessity of the inclusion of the long-range electrostatic contribution.

  19. Long-range distributed Brillouin fiber sensors by use of an unbalanced double sideband probe.

    PubMed

    Bernini, Romeo; Minardo, Aldo; Zeni, Luigi

    2011-11-21

    We propose and demonstrate a long-range Brillouin Optical Time-Domain Analysis (BOTDA) distributed sensing system making use of an unbalanced double sideband probe formed by a Stokes and an anti-Stokes line. In particular, we show that for each measuring condition an optimal Stokes /anti-Stokes input power ratio exists, allowing a larger suppression of nonlocal effects induced by pump depletion. Experiments on a 50 km single-mode sensing fiber with 5 meters spatial resolution are reported.

  20. Long-range maintenance planning: A case study of working system

    SciTech Connect

    Flanigan, M.J.

    1991-10-01

    This paper addresses the development of the Lawrence Livermore National Laboratory (LLNL) Maintenance Planning System (MPS). The pitfalls encountered and overcome, and future expansion plans. The MPS provides the ability to develop and track long-range programs, i.e., conversion of chlorofluorocarbon (CFC) equipment to hydrochlorofluorocaron (HCFC), roofing, roads, etc., in addition to providing invaluable information and data for current year budget justification.

  1. Probabilistic and Statistical Modeling of Complex Systems Exhibiting Long Range Dependence and Heavy Tails

    DTIC Science & Technology

    2010-07-01

    Gaussian, often driven by Poisson or Levy noises, and often possessed heavy tails and/or long range dependence; often models exhibited unusual fractal and...variance? A paradox and an explanation’’. Quantitative Finance , 1, 11 pages. Hult, H. and Samorodnitsky, G. (2010) ``Large deviations for point...8217’. Samorodnitsky, G. Conference on Recent Advances in Heavy Tailed Modeling in Finance , Brussels, April 28-30, 2010. Talk: Do financial return have finite or

  2. Two-loop Feynman integrals for ϕ4 theory with long-range correlated disorder

    NASA Astrophysics Data System (ADS)

    Dudka, M.

    2015-01-01

    Two-loop massive Feynman integrals for ϕ4 field-theoretical model with long-range correlated disorder are considered. Massive integrals for the vertex function Γ(4) including two or three massless propagators for generic space dimension and for any value of the correlation parameter are evaluated analytically applying Mellin-Barnes method as well as familiar representation for one-loop integrals. Obtained expressions are presented in the form of hypergeometric functions.

  3. Real-space, mean-field algorithm to numerically calculate long-range interactions

    NASA Astrophysics Data System (ADS)

    Cadilhe, A.; Costa, B. V.

    2016-02-01

    Long-range interactions are known to be of difficult treatment in statistical mechanics models. There are some approaches that introduce a cutoff in the interactions or make use of reaction field approaches. However, those treatments suffer the illness of being of limited use, in particular close to phase transitions. The use of open boundary conditions allows the sum of the long-range interactions over the entire system to be done, however, this approach demands a sum over all degrees of freedom in the system, which makes a numerical treatment prohibitive. Techniques like the Ewald summation or fast multipole expansion account for the exact interactions but are still limited to a few thousands of particles. In this paper we introduce a novel mean-field approach to treat long-range interactions. The method is based in the division of the system in cells. In the inner cell, that contains the particle in sight, the 'local' interactions are computed exactly, the 'far' contributions are then computed as the average over the particles inside a given cell with the particle in sight for each of the remaining cells. Using this approach, the large and small cells limits are exact. At a fixed cell size, the method also becomes exact in the limit of large lattices. We have applied the procedure to the two-dimensional anisotropic dipolar Heisenberg model. A detailed comparison between our method, the exact calculation and the cutoff radius approximation were done. Our results show that the cutoff-cell approach outperforms any cutoff radius approach as it maintains the long-range memory present in these interactions, contrary to the cutoff radius approximation. Besides that, we calculated the critical temperature and the critical behavior of the specific heat of the anisotropic Heisenberg model using our method. The results are in excellent agreement with extensive Monte Carlo simulations using Ewald summation.

  4. Multi-scale variability and long-range memory in indoor Radon concentrations from Coimbra, Portugal

    NASA Astrophysics Data System (ADS)

    Donner, Reik V.; Potirakis, Stelios; Barbosa, Susana

    2014-05-01

    The presence or absence of long-range correlations in the variations of indoor Radon concentrations has recently attracted considerable interest. As a radioactive gas naturally emitted from the ground in certain geological settings, understanding environmental factors controlling Radon concentrations and their dynamics is important for estimating its effect on human health and the efficiency of possible measures for reducing the corresponding exposition. In this work, we re-analyze two high-resolution records of indoor Radon concentrations from Coimbra, Portugal, each of which spans several months of continuous measurements. In order to evaluate the presence of long-range correlations and fractal scaling, we utilize a multiplicity of complementary methods, including power spectral analysis, ARFIMA modeling, classical and multi-fractal detrended fluctuation analysis, and two different estimators of the signals' fractal dimensions. Power spectra and fluctuation functions reveal some complex behavior with qualitatively different properties on different time-scales: white noise in the high-frequency part, indications of some long-range correlated process dominating time scales of several hours to days, and pronounced low-frequency variability associated with tidal and/or meteorological forcing. In order to further decompose these different scales of variability, we apply two different approaches. On the one hand, applying multi-resolution analysis based on the discrete wavelet transform allows separately studying contributions on different time scales and characterize their specific correlation and scaling properties. On the other hand, singular system analysis (SSA) provides a reconstruction of the essential modes of variability. Specifically, by considering only the first leading SSA modes, we achieve an efficient de-noising of our environmental signals, highlighting the low-frequency variations together with some distinct scaling on sub-daily time-scales resembling

  5. Long-range dispersion interactions. I. Formalism for two heteronuclear atoms

    SciTech Connect

    Zhang, J.-Y.; Mitroy, J.

    2007-08-15

    A general procedure for systematically evaluating the long-range dispersion interaction between two heteronuclear atoms in arbitrary states is outlined. The C{sub 6} dispersion parameter can always be written in terms of sum rules involving oscillator strengths only and formulas for a number of symmetry cases are given. The dispersion coefficients for excited alkali-metal atoms interacting with the ground-state H and He are tabulated.

  6. Using Amphiphilic Nanostructures to Enable Long-Range Ensemble Coalescence and Surface Rejuvenation in Dropwise Condensation

    DTIC Science & Technology

    2012-01-01

    School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States, §Air Force Research Laboratory...material with hydrophobic tips which demon- strate the ability to produce long-range, noncontact coalescence events within a heterogeneously sized...different radii of curvature supplies the driving force for coalescence and the fluidic linkage provides the pathway. A representative coalescence sequence

  7. Long-range spin accumulation from heat injection in mesoscopic superconductors with Zeeman splitting.

    PubMed

    Silaev, M; Virtanen, P; Bergeret, F S; Heikkilä, T T

    2015-04-24

    We describe far-from-equilibrium nonlocal transport in a diffusive superconducting wire with a Zeeman splitting, taking into account different spin relaxation mechanisms. We demonstrate that due to the Zeeman splitting, an injection of current in a superconducting wire creates spin accumulation that can only relax via thermalization. This effect leads to a long-range spin accumulation detectable in the nonlocal signal. Our model gives a qualitative explanation and provides accurate fits of recent experimental results in terms of realistic parameters.

  8. Agent based reasoning for the non-linear stochastic models of long-range memory

    NASA Astrophysics Data System (ADS)

    Kononovicius, A.; Gontis, V.

    2012-02-01

    We extend Kirman's model by introducing variable event time scale. The proposed flexible time scale is equivalent to the variable trading activity observed in financial markets. Stochastic version of the extended Kirman's agent based model is compared to the non-linear stochastic models of long-range memory in financial markets. The agent based model providing matching macroscopic description serves as a microscopic reasoning of the earlier proposed stochastic model exhibiting power law statistics.

  9. Saturated semiconductor optical amplifier phase modulation for long range laser radar applications.

    PubMed

    Carns, Jennifer L; Duncan, Bradley D; Dierking, Matthew P

    2012-08-20

    We investigate the use of a semiconductor optical amplifier operated in the saturation regime as a phase modulator for long range laser radar applications. The nature of the phase and amplitude modulation resulting from a high peak power Gaussian pulse, and the impact this has on the ideal pulse response of a laser radar system, is explored. We also present results of a proof-of-concept laboratory demonstration using phase-modulated pulses to interrogate a stationary target.

  10. A new smoothing function to introduce long-range electrostatic effects in QM/MM calculations

    NASA Astrophysics Data System (ADS)

    Fang, Dong; Duke, Robert E.; Cisneros, G. Andrés

    2015-07-01

    A new method to account for long range electrostatic contributions is proposed and implemented for quantum mechanics/molecular mechanics long range electrostatic correction (QM/MM-LREC) calculations. This method involves the use of the minimum image convention under periodic boundary conditions and a new smoothing function for energies and forces at the cutoff boundary for the Coulomb interactions. Compared to conventional QM/MM calculations without long-range electrostatic corrections, the new method effectively includes effects on the MM environment in the primary image from its replicas in the neighborhood. QM/MM-LREC offers three useful features including the avoidance of calculations in reciprocal space (k-space), with the concomitant avoidance of having to reproduce (analytically or approximately) the QM charge density in k-space, and the straightforward availability of analytical Hessians. The new method is tested and compared with results from smooth particle mesh Ewald (PME) for three systems including a box of neat water, a double proton transfer reaction, and the geometry optimization of the critical point structures for the rate limiting step of the DNA dealkylase AlkB. As with other smoothing or shifting functions, relatively large cutoffs are necessary to achieve comparable accuracy with PME. For the double-proton transfer reaction, the use of a 22 Å cutoff shows a close reaction energy profile and geometries of stationary structures with QM/MM-LREC compared to conventional QM/MM with no truncation. Geometry optimization of stationary structures for the hydrogen abstraction step by AlkB shows some differences between QM/MM-LREC and the conventional QM/MM. These differences underscore the necessity of the inclusion of the long-range electrostatic contribution.

  11. Local and long-range realizations of a spin-reorientation surface phase transition

    NASA Astrophysics Data System (ADS)

    He, G.; Winch, H.; Belanger, R.; Nguyen, P. H.; Venus, D.

    2017-03-01

    The spin-reorientation transition of an ultrathin film from perpendicular to in-plane magnetization is driven by a competition between dipole and anisotropy energies. In situ measurements of the magnetic susceptibility of Fe/2 monolayers (ML) Ni/W(110) films as a function of Fe coverage, made as the films are deposited at constant temperature, show two clear peaks that are described quantitatively as a long-range and a local realization of the transition. In the long-range realization, the susceptibility probes the striped domain pattern that is formed in response to the balance of energetics on a mesoscopic scale. Here the reorientation transition occurs at a noninteger layer thickness. In the local realization, the susceptibility probes the response of small islands with in-plane anisotropy in the third atomic Fe layer that are grown on the second atomic Fe layer, which has perpendicular anisotropy. It is a response to the local finite-size, metastable energetics due to discrete steps in thickness. An excellent quantitative description of the susceptibility data is obtained when both local and long-range aspects of the spin-reorientation transition are included.

  12. Viability of long range dragonfly migration across the Indian Ocean: An energetics perspective

    NASA Astrophysics Data System (ADS)

    Saha, Sandeep; Nirwal, Satvik

    2016-11-01

    Recently Pantala flavescens (dragonflies) have been reported to migrate in millions from India to Eastern Africa on a multigenerational migratory circuit of length 14000-18000 kms. We attempt to understand the ability of dragonflies to perform long range migration by examining the energetics using computer simulations. In absence of a theory for long range insect migrations, we resort to the extensive literature on long range bird migration from the energetics perspective. The flight energetics depends upon instantaneous power and velocity. The mechanical flight power is computed from the power curve which is then converted to mass depletion using Brequet's equation. However, the mechanical flight power itself depends upon the instantaneous velocity which can vary depending upon the current mass. In order to predict the range in our simulations, we assume that the insect progressively tries to achieve the maximum range velocity. The results indicate that the migration range is approximately 1260 kms in 70 hours based on the true airspeed. However, our analysis is restricted by the lack of data and certain caveats in drag prediction and basal metabolism rate.

  13. A modified Variable-Phase algorithm for multichannel scattering with long-range potentials

    NASA Astrophysics Data System (ADS)

    Martinazzo, R.; Bodo, E.; Gianturco, F. A.

    2003-03-01

    A new Variable-Phase (VP) algorithm for solving the close coupled equations of inelastic scattering in atom-molecule collisions driven by a strong long range potential is presented. The proposed method allows for a rigorous, gradual reduction of the number of closed channels during the outward propagation of the solution of the VP equations. In this way it allows a considerable saving of CPU time when dealing with strong, long-range potentials. A further saving of computational time is achieved by the use of a zero order effective potential in the reference problem which avoids the calculation of the computationally expensive Bessel functions. The K matrix version of the VP equations are solved with a standard Runge-Kutta integrator with adaptive step size. The low-energy, rotational excitation process in the LiH-H + system is used to test the resulting algorithm and we show that the present method once applied to long-range interactions, can be orders of magnitude faster than the widely used, adaptive-step size LogDerivative/Airy propagator while keeping the same level of accuracy.

  14. Tuneable and robust long range surface plasmon resonance for biosensing applications

    NASA Astrophysics Data System (ADS)

    Méjard, Régis; Dostálek, Jakub; Huang, Chun-Jen; Griesser, Hans; Thierry, Benjamin

    2013-10-01

    A multilayered biosensing architecture based on long range surface plasmons (LRSPs) is reported. LRSPs originate from the coupling of surface plasmons on the opposite sides of a thin metal film embedded in a symmetrical refractive index environment. With respect to regular SPs, LRSPs are characterized by extended electromagnetic field profiles and lower losses, making them of high interest in biosensing, especially for large biological entities. LRSPs-supporting layer structures are typically prepared by using fluoropolymers with refractive indices close to that of water. Unfortunately, fluoropolymers have low surface energies which can translate into poor adhesion to substrates and sub-optimal properties of coatings with surface plasmon resonance-active metal layers such as gold. In this work, a multilayered fluoropolymer structure with tuneable average refractive index is described and used to adjust the penetration depth of LRSP from the sensor surface. The proposed methodology also provides a simple solution to increase the adhesion of LRSP-supporting structures to glass substrates. Towards taking full advantage of long range surface plasmon resonance sensors, a novel approach based on the plasma-polymerization of allylamine is also described to improve the quality of gold layers on fluoropolymers such as Teflon AF. Through these advancements, long range surface plasmon resonance sensors were fabricated with figures of merit as high as 466 RIU-1. The remarkable performance of these sensors combined with their high stability is expected to foster applications of LRSPR in biosensing.

  15. The ESCRT machinery regulates the secretion and long-range activity of Hedgehog.

    PubMed

    Matusek, Tamás; Wendler, Franz; Polès, Sophie; Pizette, Sandrine; D'Angelo, Gisela; Fürthauer, Maximilian; Thérond, Pascal P

    2014-12-04

    The conserved family of Hedgehog (Hh) proteins acts as short- and long-range secreted morphogens, controlling tissue patterning and differentiation during embryonic development. Mature Hh carries hydrophobic palmitic acid and cholesterol modifications essential for its extracellular spreading. Various extracellular transportation mechanisms for Hh have been suggested, but the pathways actually used for Hh secretion and transport in vivo remain unclear. Here we show that Hh secretion in Drosophila wing imaginal discs is dependent on the endosomal sorting complex required for transport (ESCRT). In vivo the reduction of ESCRT activity in cells producing Hh leads to a retention of Hh at the external cell surface. Furthermore, we show that ESCRT activity in Hh-producing cells is required for long-range signalling. We also provide evidence that pools of Hh and ESCRT proteins are secreted together into the extracellular space in vivo and can subsequently be detected together at the surface of receiving cells. These findings uncover a new function for ESCRT proteins in controlling morphogen activity and reveal a new mechanism for the transport of secreted Hh across the tissue by extracellular vesicles, which is necessary for long-range target induction.

  16. Long-range energy transport in single supramolecular nanofibres at room temperature

    NASA Astrophysics Data System (ADS)

    Haedler, Andreas T.; Kreger, Klaus; Issac, Abey; Wittmann, Bernd; Kivala, Milan; Hammer, Natalie; Köhler, Jürgen; Schmidt, Hans-Werner; Hildner, Richard

    2015-07-01

    Efficient transport of excitation energy over long distances is a key process in light-harvesting systems, as well as in molecular electronics. However, in synthetic disordered organic materials, the exciton diffusion length is typically only around 10 nanometres (refs 4, 5), or about 50 nanometres in exceptional cases, a distance that is largely determined by the probability laws of incoherent exciton hopping. Only for highly ordered organic systems has the transport of excitation energy over macroscopic distances been reported--for example, for triplet excitons in anthracene single crystals at room temperature, as well as along single polydiacetylene chains embedded in their monomer crystalline matrix at cryogenic temperatures (at 10 kelvin, or -263 degrees Celsius). For supramolecular nanostructures, uniaxial long-range transport has not been demonstrated at room temperature. Here we show that individual self-assembled nanofibres with molecular-scale diameter efficiently transport singlet excitons at ambient conditions over more than four micrometres, a distance that is limited only by the fibre length. Our data suggest that this remarkable long-range transport is predominantly coherent. Such coherent long-range transport is achieved by one-dimensional self-assembly of supramolecular building blocks, based on carbonyl-bridged triarylamines, into well defined H-type aggregates (in which individual monomers are aligned cofacially) with substantial electronic interactions. These findings may facilitate the development of organic nanophotonic devices and quantum information technology.

  17. Long-range energy transport in single supramolecular nanofibres at room temperature.

    PubMed

    Haedler, Andreas T; Kreger, Klaus; Issac, Abey; Wittmann, Bernd; Kivala, Milan; Hammer, Natalie; Köhler, Jürgen; Schmidt, Hans-Werner; Hildner, Richard

    2015-07-09

    Efficient transport of excitation energy over long distances is a key process in light-harvesting systems, as well as in molecular electronics. However, in synthetic disordered organic materials, the exciton diffusion length is typically only around 10 nanometres (refs 4, 5), or about 50 nanometres in exceptional cases, a distance that is largely determined by the probability laws of incoherent exciton hopping. Only for highly ordered organic systems has the transport of excitation energy over macroscopic distances been reported--for example, for triplet excitons in anthracene single crystals at room temperature, as well as along single polydiacetylene chains embedded in their monomer crystalline matrix at cryogenic temperatures (at 10 kelvin, or -263 degrees Celsius). For supramolecular nanostructures, uniaxial long-range transport has not been demonstrated at room temperature. Here we show that individual self-assembled nanofibres with molecular-scale diameter efficiently transport singlet excitons at ambient conditions over more than four micrometres, a distance that is limited only by the fibre length. Our data suggest that this remarkable long-range transport is predominantly coherent. Such coherent long-range transport is achieved by one-dimensional self-assembly of supramolecular building blocks, based on carbonyl-bridged triarylamines, into well defined H-type aggregates (in which individual monomers are aligned cofacially) with substantial electronic interactions. These findings may facilitate the development of organic nanophotonic devices and quantum information technology.

  18. Computational study of the ZGB model with a long-range interaction

    NASA Astrophysics Data System (ADS)

    Chan, Chor-Hoi; Rikvold, Per Arne

    2014-03-01

    The Ziff-Gulari-Barshad (ZGB) model is widely used to study the oxidation of carbon monoxide (CO) on a catalyst surface. It exhibits a non-equilibrium, discontinuous phase transition between a reactive and a CO poisoned phase. If one allows a nonzero rate of CO desorption (k), the line of phase transitions is terminated at a critical point (kc). In this work, instead of restricting the CO and atomic oxygen (O) to react only when they are absorbed in close proximity, we consider a model that allows CO and O atoms adsorbed far apart on the lattice to react to form carbon dioxide (CO2). We employ Monte Carlo simulations to study the critical properties of this system, and we find that the non-equilibrium critical point changes from the Ising universality class to the mean-field universality class upon introducing even a very weak long-range interaction term. This behavior is consistent with that of the equilibrium Ising ferromagnet with additional weak long-range interactions. Through this study we hope to gain further understanding of the ways that a long-range interaction can affect an originally short-range interacting non-equilibrium system. Supported by NSF DMR-1104829.

  19. Extension and evaluation of the multilevel summation method for fast long-range electrostatics calculations.

    PubMed

    Moore, Stan G; Crozier, Paul S

    2014-06-21

    Several extensions and improvements have been made to the multilevel summation method (MSM) of computing long-range electrostatic interactions. These include pressure calculation, an improved error estimator, faster direct part calculation, extension to non-orthogonal (triclinic) systems, and parallelization using the domain decomposition method. MSM also allows fully non-periodic long-range electrostatics calculations which are not possible using traditional Ewald-based methods. In spite of these significant improvements to the MSM algorithm, the particle-particle particle-mesh (PPPM) method was still found to be faster for the periodic systems we tested on a single processor. However, the fast Fourier transforms (FFTs) that PPPM relies on represent a major scaling bottleneck for the method when running on many cores (because the many-to-many communication pattern of the FFT becomes expensive) and MSM scales better than PPPM when using a large core count for two test problems on Sandia's Redsky machine. This FFT bottleneck can be reduced by running PPPM on only a subset of the total processors. MSM is most competitive for relatively low accuracy calculations. On Sandia's Chama machine, however, PPPM is found to scale better than MSM for all core counts that we tested. These results suggest that PPPM is usually more efficient than MSM for typical problems running on current high performance computers. However, further improvements to MSM algorithm could increase its competitiveness for calculation of long-range electrostatic interactions.

  20. Short- and long-range neural synchrony in grapheme-color synesthesia.

    PubMed

    Volberg, Gregor; Karmann, Anna; Birkner, Stefanie; Greenlee, Mark W

    2013-07-01

    Grapheme-color synesthesia is a perceptual phenomenon where single graphemes (e.g., the letter "E") induce simultaneous sensations of colors (e.g., the color green) that were not objectively shown. Current models disagree as to whether the color sensations arise from increased short-range connectivity between anatomically adjacent grapheme- and color-processing brain structures or from decreased effectiveness of inhibitory long-range connections feeding back into visual cortex. We addressed this issue by examining neural synchrony obtained from EEG activity, in a sample of grapheme-color synesthetes that were presented with color-inducing versus non-color-inducing graphemes. For color-inducing graphemes, the results showed a decrease in the number of long-range couplings in the theta frequency band (4-7 Hz, 280-540 msec) and a concurrent increase of short-range phase-locking within lower beta band (13-20 Hz, 380-420 msec at occipital electrodes). Because the effects were both found in long-range synchrony and later within the visual processing stream, the results support the idea that reduced inhibition is an important factor for the emergence of synesthetic colors.