WorldWideScience

Sample records for wall motion synchrony

  1. Exit from Synchrony in Joint Improvised Motion

    Science.gov (United States)

    Dahan, Assi; Noy, Lior; Hart, Yuval; Mayo, Avi; Alon, Uri

    2016-01-01

    Motion synchrony correlates with effective and well-rated human interaction. However, people do not remain locked in synchrony; Instead, they repeatedly enter and exit synchrony. In many important interactions, such as therapy, marriage and parent-infant communication, it is the ability to exit and then re-enter synchrony that is thought to build strong relationship. The phenomenon of entry into zero-phase synchrony is well-studied experimentally and in terms of mathematical modeling. In contrast, exit-from-synchrony is under-studied. Here, we focus on human motion coordination, and examine the exit-from-synchrony phenomenon using experimental data from the mirror game paradigm, in which people perform joint improvised motion, and from human tracking of computer-generated stimuli. We present a mathematical mechanism that captures aspects of exit-from-synchrony in human motion. The mechanism adds a random motion component when the accumulated velocity error between the players is small. We introduce this mechanism to several models for human coordinated motion, including the widely studied HKB model, and the predictor-corrector model of Noy, Dekel and Alon. In all models, the new mechanism produces realistic simulated behavior when compared to experimental data from the mirror game and from tracking of computer generated stimuli, including repeated entry and exit from zero-phase synchrony that generates a complexity of motion similar to that of human players. We hope that these results can inform future research on exit-from-synchrony, to better understand the dynamics of coordinated action of people and to enhance human-computer and human-robot interaction. PMID:27711185

  2. Perceptual synchrony of audiovisual streams for natural and artificial motion sequences.

    Science.gov (United States)

    Arrighi, Roberto; Alais, David; Burr, David

    2006-03-16

    We investigated the conditions necessary for perceptual simultaneity of visual and auditory stimuli under natural conditions: video sequences of conga drumming at various rhythms. Under most conditions, the auditory stream needs to be delayed for sight and sound to be perceived simultaneously. The size of delay for maximum perceived simultaneity varied inversely with drumming tempo, from about 100 ms at 1 Hz to 30 ms at 4 Hz. Random drumming motion produced similar results, with higher random tempos requiring less delay. Video sequences of disk stimuli moving along a motion profile matched to the drummer produced near-identical results. When the disks oscillated at constant speed rather than following "biological" speed variations, the delays necessary for perceptual synchrony were systematically less. The results are discussed in terms of real-world constraints for perceptual synchrony and possible neural mechanisms.

  3. Psychological Data from an Exploration of the Rapport / Synchrony Interplay Using Motion Energy Analysis

    Directory of Open Access Journals (Sweden)

    Andrew Nelson

    2014-07-01

    Full Text Available These data result from an investigation examining the interplay between dyadic rapport and consequential behavior-mirroring. Participants responded to a variety of interpersonally-focused pretest measures prior to their engagement in videotaped interdependent tasks (coded for interactional synchrony using Motion Energy Analysis [17,18]. A post-task evaluation of rapport and other related constructs followed each exchange. Four studies shared these same dependent measures, but asked distinct questions: Study 1 (Ndyad = 38 explored the influence of perceived responsibility and gender-specificity of the task; Study 2 (Ndyad = 51 focused on dyad sex-makeup; Studies 3 (Ndyad = 41 and 4 (Ndyad = 63 examined cognitive load impacts on the interactions. Versions of the data are structured with both individual and dyad as the unit of analysis. Our data possess strong reuse potential for theorists interested in dyadic processes and are especially pertinent to questions about dyad agreement and interpersonal perception / behavior association relationships.

  4. EEG frequency tagging dissociates between neural processing of motion synchrony and human quality of multiple point-light dancers

    Science.gov (United States)

    Alp, Nihan; Nikolaev, Andrey R.; Wagemans, Johan; Kogo, Naoki

    2017-01-01

    Do we perceive a group of dancers moving in synchrony differently from a group of drones flying in-sync? The brain has dedicated networks for perception of coherent motion and interacting human bodies. However, it is unclear to what extent the underlying neural mechanisms overlap. Here we delineate these mechanisms by independently manipulating the degree of motion synchrony and the humanoid quality of multiple point-light displays (PLDs). Four PLDs moving within a group were changing contrast in cycles of fixed frequencies, which permits the identification of the neural processes that are tagged by these frequencies. In the frequency spectrum of the steady-state EEG we found two emergent frequency components, which signified distinct levels of interactions between PLDs. The first component was associated with motion synchrony, the second with the human quality of the moving items. These findings indicate that visual processing of synchronously moving dancers involves two distinct neural mechanisms: one for the perception of a group of items moving in synchrony and one for the perception of a group of moving items with human quality. We propose that these mechanisms underlie high-level perception of social interactions. PMID:28272421

  5. Power optimization for domain wall motion in ferromagnetic nanowires

    Science.gov (United States)

    Tretiakov, O. A.; Liu, Y.; Abanov, Ar.

    2011-04-01

    The current mediated domain-wall dynamics in a thin ferromagnetic wire is investigated. We derive the effective equations of motion of the domain wall. They are used to study the possibility to optimize the power supplied by electric current for the motion of domain walls in a nanowire. We show that a certain resonant time-dependent current moving a domain wall can significantly reduce the Joule heating in the wire, and thus it can lead to a novel proposal for the most energy efficient memory devices. We discuss how Gilbert damping, nonadiabatic spin transfer torque, and the presence of Dzyaloshinskii-Moriya interaction can effect this power optimization.

  6. Power optimization for domain wall motion in ferromagnetic nanowires

    OpenAIRE

    Tretiakov, Oleg A.; Liu, Y.; Abanov, Ar.

    2010-01-01

    The current mediated domain-wall dynamics in a thin ferromagnetic wire is investigated. We derive the effective equations of motion of the domain wall. They are used to study the possibility to optimize the power supplied by electric current for the motion of domain walls in a nanowire. We show that a certain resonant time-dependent current moving a domain wall can significantly reduce the Joule heating in the wire, and thus it can lead to a novel proposal for the most energy efficient memory...

  7. Options for assessing and measuring chest wall motion.

    Science.gov (United States)

    Seddon, Paul

    2015-01-01

    Assessing chest wall motion is a basic and vital component in managing the child with respiratory problems, whether these are due to pathology in the lungs, airways, chest wall or muscles. Since the 1960s, clinical assessment has been supplemented with an ever-growing range of technological options for measuring chest wall motion, each with unique advantages and disadvantages. Measurements of chest wall motion can be used to: (1) Assess respiratory airflow and volume change, as a non-invasive alternative to measurement at the airway opening, (2) Monitor breathing over long periods of time, to identify apnoea and other types of sleep-disordered breathing, (3)Identify and quantify patterns of abnormal chest wall movement, whether between ribcage and abdominal components (thoracoabdominal asynchrony) or between different regions of the ribcage (eg in scoliosis and pectus excavatum). Measuring chest wall motion allows us to do things which simply cannot be done by more mainstream respiratory function techniques measuring flow at the airway opening: it allows respiratory airflow to be measured when it would otherwise be impossible, and it tells us how the different parts of the chest wall (eg ribcage vs abdomen, right vs left) are moving in order to generate that airflow. The basis of the different techniques available to assess and measure chest wall motion will be reviewed and compared, and their relevance to paediatric respiratory practice assessed.

  8. Motional Effect on Wall Shear Stresses

    DEFF Research Database (Denmark)

    Kock, Samuel Alberg; Torben Fründ, Ernst; Yong Kim, Won

    Atherosclerosis is the leading cause of death and severe disability. Wall Shear Stress (WSS), the stress exerted on vessel walls by the flowing blood is a key factor in the development of atherosclerosis. Computational Fluid Dynamics (CFD) is widely used for WSS estimations. Most CFD simulations...... are based on static models to ease computational burden leading to inaccurate estimations. The aim of this work was to estimate the effect of vessel wall deformations (expansion and bending) on WSS levels....

  9. Synchrony in Dyadic Psychotherapy Sessions

    Science.gov (United States)

    Ramseyer, Fabian; Tschacher, Wolfgang

    Synchrony is a multi-faceted concept used in diverse domains such as physics, biology, and the social sciences. This chapter reviews some of the evidence of nonverbal synchrony in human communication, with a main focus on the role of synchrony in the psychotherapeutic setting. Nonverbal synchrony describes coordinated behavior of patient and therapist. Its association with empathy, rapport and the therapeutic relationship has been pointed out repeatedly, yet close evaluation of empirical studies suggests that the evidence remains inconclusive. Particularly in naturalistic studies, research with quantitative measures of synchrony is still lacking. We introduce a new empirical approach for the study of synchrony in psychotherapies under field conditions: Motion Energy Analysis (MEA). This is a video-based algorithm that quantifies the amount of movement in freely definable regions of interest. Our statistical analysis detects synchrony on a global level, irrespective of the specific body parts moving. Synchrony thus defined can be considered as a general measure of movement coordination between interacting individuals. Data from a sequence of N = 21 therapy sessions taken from one psychotherapy dyad shows a high positive relationship between synchrony and the therapeutic bond. Nonverbal synchrony can thus be considered a promising concept for research on the therapeutic alliance. Further areas of application are discussed.

  10. A motion capture study to measure the feeling of synchrony in romantic couples and in professional musicians

    Directory of Open Access Journals (Sweden)

    Delphine Preissmann

    2016-10-01

    Full Text Available The feeling of synchrony is fundamental for most social activities and prosocial behaviors. However, little is known about the behavioral correlates of this feeling and its modulation by intergroup differences. We previously showed that the subjective feeling of synchrony in subjects involved in a mirror imitation task was modulated by objective behavioral measures, as well as contextual factors such as task difficulty and duration of the task performance. In the present study, we extended our methodology to investigate possible interindividual differences. We hypothesized that being in a romantic relationship or being a professional musician can modulate both implicit and explicit synchronisation and the feeling of synchrony as well as the ability to detect synchrony from a third person perspective. Contrary to our hypothesis, we did not find significant differences between people in a romantic relationship and control subjects. However, we observed differences between musicians and control subjects. For the implicit synchrony (spontaneous synchronization during walking, the results revealed that musicians that had never met before spontaneously synchronized their movements earlier among themselves than control subjects, but not better than people sharing a romantic relationship. Moreover, in explicit behavioral synchronisation tasks (mirror game, musicians reported earlier feeling of synchrony and had less speed errors than control subjects. This was in interaction with tasks difficulty as these differences appeared only in tasks with intermediate difficulty. Finally, when subjects had to judge synchrony from a third person perspective, musicians had a better performance to identify if they were present or not in the videos. Taken together, our results suggest that being a professional musician can play a role in the feeling of synchrony and its underlying mechanisms.

  11. A Motion Capture Study to Measure the Feeling of Synchrony in Romantic Couples and in Professional Musicians.

    Science.gov (United States)

    Preissmann, Delphine; Charbonnier, Caecilia; Chagué, Sylvain; Antonietti, Jean-Philippe; Llobera, Joan; Ansermet, Francois; Magistretti, Pierre J

    2016-01-01

    The feeling of synchrony is fundamental for most social activities and prosocial behaviors. However, little is known about the behavioral correlates of this feeling and its modulation by intergroup differences. We previously showed that the subjective feeling of synchrony in subjects involved in a mirror imitation task was modulated by objective behavioral measures, as well as contextual factors such as task difficulty and duration of the task performance. In the present study, we extended our methodology to investigate possible interindividual differences. We hypothesized that being in a romantic relationship or being a professional musician can modulate both implicit and explicit synchronization and the feeling of synchrony as well as the ability to detect synchrony from a third person perspective. Contrary to our hypothesis, we did not find significant differences between people in a romantic relationship and control subjects. However, we observed differences between musicians and control subjects. For the implicit synchrony (spontaneous synchronization during walking), the results revealed that musicians that had never met before spontaneously synchronized their movements earlier among themselves than control subjects, but not better than people sharing a romantic relationship. Moreover, in explicit behavioral synchronization tasks (mirror game), musicians reported earlier feeling of synchrony and had less speed errors than control subjects. This was in interaction with tasks difficulty as these differences appeared only in tasks with intermediate difficulty. Finally, when subjects had to judge synchrony from a third person perspective, musicians had a better performance to identify if they were present or not in the videos. Taken together, our results suggest that being a professional musician can play a role in the feeling of synchrony and its underlying mechanisms.

  12. A Motion Capture Study to Measure the Feeling of Synchrony in Romantic Couples and in Professional Musicians

    KAUST Repository

    Preissmann, Delphine

    2016-10-27

    The feeling of synchrony is fundamental for most social activities and prosocial behaviors. However, little is known about the behavioral correlates of this feeling and its modulation by intergroup differences. We previously showed that the subjective feeling of synchrony in subjects involved in a mirror imitation task was modulated by objective behavioral measures, as well as contextual factors such as task difficulty and duration of the task performance. In the present study, we extended our methodology to investigate possible interindividual differences. We hypothesized that being in a romantic relationship or being a professional musician can modulate both implicit and explicit synchronization and the feeling of synchrony as well as the ability to detect synchrony from a third person perspective. Contrary to our hypothesis, we did not find significant differences between people in a romantic relationship and control subjects. However, we observed differences between musicians and control subjects. For the implicit synchrony (spontaneous synchronization during walking), the results revealed that musicians that had never met before spontaneously synchronized their movements earlier among themselves than control subjects, but not better than people sharing a romantic relationship. Moreover, in explicit behavioral synchronization tasks (mirror game), musicians reported earlier feeling of synchrony and had less speed errors than control subjects. This was in interaction with tasks difficulty as these differences appeared only in tasks with intermediate difficulty. Finally, when subjects had to judge synchrony from a third person perspective, musicians had a better performance to identify if they were present or not in the videos. Taken together, our results suggest that being a professional musician can play a role in the feeling of synchrony and its underlying mechanisms. © 2016 Preissmann, Charbonnier, Chagué, Antonietti, Llobera, Ansermet and Magistretti.

  13. Induced motion of domain walls in multiferroics with quadratic interaction

    Energy Technology Data Exchange (ETDEWEB)

    Gerasimchuk, Victor S., E-mail: viktor.gera@gmail.com [National Technical University of Ukraine “Kyiv Polytechnic Institute”, Peremohy Avenue 37, 03056 Kiev (Ukraine); Shitov, Anatoliy A., E-mail: shitov@mail.ru [Donbass National Academy of Civil Engineering, Derzhavina Street 2, 86123 Makeevka, Donetsk Region (Ukraine)

    2013-10-15

    We theoretically study the dynamics of 180-degree domain wall of the ab-type in magnetic materials with quadratic magnetoelectric interaction in external alternating magnetic and electric fields. The features of the oscillatory and translational motions of the domain walls and stripe structures depending on the parameters of external fields and characteristics of the multiferroics are discussed. The possibility of the domain walls drift in a purely electric field is established. - Highlights: • We study DW and stripe DS in multiferroics with quadratic magnetoelectric interaction. • We build up the theory of oscillatory and translational (drift) DW and DS motion. • DW motion can be caused by crossed alternating electric and magnetic fields. • DW motion can be caused by alternating “pure” electric field. • DW drift velocity is formed by the AFM and Dzyaloshinskii interaction terms.

  14. Time-periodic N\\'eel wall motions

    CERN Document Server

    Huber, Alexander

    2010-01-01

    In thin ferromagnetic films, the predominance of the magnetic shape anisotropy leads to in-plane magnetizations. The simplest domain wall in this geometry is the one-dimensional Neel wall that connects two magnetizations of opposite sign by a planar 180 degree rotation. In this paper, we perturb the static Neel wall profile in order to construct time-periodic Neel wall motions governed by to the Landau-Lifshitz-Gilbert equation. Our construction works within a certain parameter regime and requires the restriction to external magnetic fields with small amplitudes and suitable time averages.

  15. Intraventricular flow alterations due to dyssynchronous wall motion

    Science.gov (United States)

    Pope, Audrey M.; Lai, Hong Kuan; Samaee, Milad; Santhanakrishnan, Arvind

    2015-11-01

    Roughly 30% of patients with systolic heart failure suffer from left ventricular dyssynchrony (LVD), in which mechanical discoordination of the ventricle walls leads to poor hemodynamics and suboptimal cardiac function. There is currently no clear mechanistic understanding of how abnormalities in septal-lateral (SL) wall motion affects left ventricle (LV) function, which is needed to improve the treatment of LVD using cardiac resynchronization therapy. We use an experimental flow phantom with an LV physical model to study mechanistic effects of SL wall motion delay on LV function. To simulate mechanical LVD, two rigid shafts were coupled to two segments (apical and mid sections) along the septal wall of the LV model. Flow through the LV model was driven using a piston pump, and stepper motors coupled to the above shafts were used to locally perturb the septal wall segments relative to the pump motion. 2D PIV was used to examine the intraventricular flow through the LV physical model. Alterations to SL delay results in a reduction in the kinetic energy (KE) of the flow field compared to synchronous SL motion. The effect of varying SL motion delay from 0% (synchronous) to 100% (out-of-phase) on KE and viscous dissipation will be presented. This research was supported by the Oklahoma Center for Advancement of Science and Technology (HR14-022).

  16. Rising motion of a bubble layer near a vertical wall

    Science.gov (United States)

    Dabiri, Sadegh; Bhuvankar, Pramod

    2015-11-01

    Bubbly flows in vertical pipes and channels form a wall-peak distribution of bubbles under certain conditions. The dynamics of the bubbles near the wall is different than in an unbounded liquid. Here we report the rising motion of bubbles in a liquid near a vertical wall. In a simulation of a bubbly flow in a periodic domain with a vertical wall on one side, an average pressure gradient is applied to the domain that balances the weight of the liquid phase. The upward flow is created by the rising motion of the bubbles. The bubbles are kept near the wall by the lateral lift force acting on them as a result of rising in a shear flow which is in turn generated by rising motion of bubbles. The rise velocity of the bubbles on the wall and the average rise velocity of the liquid depend on three dimensionless parameters, Archimedes number, Eotvos number, and the average volume fraction of bubbles near the wall. In the limit of small Eo, bubbles are nearly spherical and the dependency on Eo becomes negligible. In this limit, the scaling of the liquid Reynolds number with Archimedes number and the void fraction is presented.

  17. Submicrometric 2D ratchet effect in magnetic domain wall motion

    Energy Technology Data Exchange (ETDEWEB)

    Castán-Guerrero, C., E-mail: ccastan@unizar.es [Instituto de Ciencia de Materiales de Aragón (ICMA), CSIC – Universidad de Zaragoza, E-50009 Zaragoza (Spain); Dpto. de Física de la Materia Condensada, Universidad de Zaragoza, E-50009 Zaragoza (Spain); Herrero-Albillos, J. [Fundación ARAID, E-50004 Zaragoza (Spain); Centro Universitario de la Defensa, E-50090 Zaragoza (Spain); Instituto de Ciencia de Materiales de Aragón (ICMA), CSIC – Universidad de Zaragoza, E-50009 Zaragoza (Spain); Sesé, J. [Instituto de Nanociencia de Aragón, Laboratorio de Microscopías Avanzadas, Universidad de Zaragoza, E-50018 Zaragoza (Spain); Dpto. de Física de la Materia Condensada, Universidad de Zaragoza, E-50009 Zaragoza (Spain); Bartolomé, J.; Bartolomé, F. [Instituto de Ciencia de Materiales de Aragón (ICMA), CSIC – Universidad de Zaragoza, E-50009 Zaragoza (Spain); Dpto. de Física de la Materia Condensada, Universidad de Zaragoza, E-50009 Zaragoza (Spain); Hierro-Rodriguez, A.; Valdés-Bango, F.; Martín, J.I.; Alameda, J.M. [Dpto. Física, Universidad de Oviedo, Asturias (Spain); CINN (CSIC – Universidad de Oviedo – Principado de Asturias), Asturias (Spain); García, L.M. [Instituto de Ciencia de Materiales de Aragón (ICMA), CSIC – Universidad de Zaragoza, E-50009 Zaragoza (Spain); Dpto. de Física de la Materia Condensada, Universidad de Zaragoza, E-50009 Zaragoza (Spain)

    2014-12-15

    Strips containing arrays of submicrometric triangular antidots with a 2D square periodicity have been fabricated by electron beam lithography. A clear ratchet effect of 180° domain wall motion under a varying applied field parallel to the walls has been observed. The direction is determined by the direction of the triangle vertices. In contrast, no ratchet effect is observed when the antidot array is constituted by symmetric rhomb-shaped antidots.

  18. Magnetic domain wall motion triggered by electric field

    Energy Technology Data Exchange (ETDEWEB)

    Pyatakov, A P; Sergeev, A S; Sechin, D A; Meshkov, G A; Nikolaeva, E P; Nikolaev, A V; Logginov, A S [Physics Department, M.V. Lomonosov Moscow State University, Leninskie gory, Moscow, 119296 (Russian Federation); Zvezdin, A K, E-mail: pyatakov@phys.msu.r [A.M. Prokhorov General Physics Institute, 38, Vavilova st., Moscow, 119991 (Russian Federation)

    2010-01-01

    We propose the new approach to the problem of electrically controlled magnetic state: the electric field driven domain wall motion. The effect is demonstrated in iron garnet films in ambient conditions. The theoretical model based on inhomogenous magnetoelectric interaction provides with the necessary criteria of the effect and the way to maximize it.

  19. Linear motion feed through with thin wall rubber sealing element

    Science.gov (United States)

    Mikhailov, V. P.; Deulin, E. A.

    2017-07-01

    The patented linear motion feedthrough is based on elastic thin rubber walls usage being reinforced with analeptic string fixed in the middle part of the walls. The pneumatic or hydro actuators create linear movement of stock. The length of this movement is two times more the rubber wall length. This flexible wall is a sealing element of feedthrough. The main advantage of device is negligible resistance force that is less then mentioned one in sealing bellows that leads to positioning error decreasing. Nevertheless, the thin wall rubber sealing element (TRE) of the feedthrough is the main unreliable element that was the reason of this element longevity research. The theory and experimental results help to create equation for TRE longevity calculation under vacuum or extra high pressure difference action. The equation was used for TRE longevity determination for hydraulic or vacuum equipment realization also as it helps for gas flow being leaking through the cracks in thin walls of rubber sealing element of linear motion feedthrough calculation.

  20. Experimental Study on Current-Driven Domain Wall Motion

    Science.gov (United States)

    Ono, T.; Yamaguchi, A.; Tanigawa, H.; Yano, K.; Kasai, S.

    2006-06-01

    Current-driven domain wall (DW) motion for a well-defined single DW in a micro-fabricated magnetic wire with submicron width was investigated by real-space observation with magnetic force microscopy. Magnetic force microscopy visualizes that a single DW introduced in a wire is displaced back and forth by positive and negative pulsed-current, respectively. Effect of the Joule heating, reduction of the threshold current density by shape control, and magnetic ratchet effect are also presented.

  1. Wellens' syndrome with segmental wall-motion abnormalities

    OpenAIRE

    Bugan, Baris; Celik,Turgay; Celik,Murat; Dermikoh,Sait; Iyisoy,Atila; Serdar ,Firtina

    2010-01-01

    Turgay Celik1, Baris Bugan1, Serdar Firtina1, Murat Celik2, Sait Demirkol1, Atila Iyisoy11Gulhane Military Medical Academy, Department of Cardiology, Ankara, Turkey; 2Van Army District Hospital, Department of Cardiology, Van, TurkeyAbstract: Wellens' syndrome is a pattern of electrocardiographic T-wave changes associated with critical, proximal left anterior descending (LAD) artery stenosis. We herein report 2 cases of Wellens' syndrome with segmental wall-motion abnormalities...

  2. Current-induced domain wall motion in nanoscale ferromagnetic elements

    Energy Technology Data Exchange (ETDEWEB)

    Malinowski, G [Laboratoire de Physique des Solides, CNRS, Universite Paris-sud 11, 91405 Orsay Cedex (France); Boulle, O [SPINTEC, CEA/CNRS/UJF/GINP, INAC, 38054 Grenoble Cedex 9 (France); Klaeui, M, E-mail: Klaeui@uni-mainz.de [SwissFEL, Paul Scherrer Institut, 5232 Villigen PSI (Switzerland); Laboratory of Nanomagnetism and Spin Dynamics, Ecole Polytechnique Federale de Lausanne (EPFL), 1015 Lausanne (Switzerland)

    2011-09-28

    We review the details of domain wall (DW) propagation due to spin-polarized currents that could potentially be used in magnetic data storage devices based on domains and DWs. We discuss briefly the basics of the underlying spin torque effect and show how the two torques arising from the interaction between the spin-polarized charge carriers and the magnetization lead to complex dynamics of a spin texture such as a DW. By direct imaging we show how confined DWs in nanowires can be displaced using currents in in-plane soft-magnetic materials, and that when using short pulses, fast velocities can be attained. For high-anisotropy out-of-plane magnetized wires with narrow DWs we present approaches to deducing the torque terms and show that in these materials potentially more efficient domain wall motion could be achieved.

  3. Rashba Torque Driven Domain Wall Motion in Magnetic Helices.

    Science.gov (United States)

    Pylypovskyi, Oleksandr V; Sheka, Denis D; Kravchuk, Volodymyr P; Yershov, Kostiantyn V; Makarov, Denys; Gaididei, Yuri

    2016-01-01

    Manipulation of the domain wall propagation in magnetic wires is a key practical task for a number of devices including racetrack memory and magnetic logic. Recently, curvilinear effects emerged as an efficient mean to impact substantially the statics and dynamics of magnetic textures. Here, we demonstrate that the curvilinear form of the exchange interaction of a magnetic helix results in an effective anisotropy term and Dzyaloshinskii-Moriya interaction with a complete set of Lifshitz invariants for a one-dimensional system. In contrast to their planar counterparts, the geometrically induced modifications of the static magnetic texture of the domain walls in magnetic helices offer unconventional means to control the wall dynamics relying on spin-orbit Rashba torque. The chiral symmetry breaking due to the Dzyaloshinskii-Moriya interaction leads to the opposite directions of the domain wall motion in left- or right-handed helices. Furthermore, for the magnetic helices, the emergent effective anisotropy term and Dzyaloshinskii-Moriya interaction can be attributed to the clear geometrical parameters like curvature and torsion offering intuitive understanding of the complex curvilinear effects in magnetism.

  4. Current-induced domain wall motion in ferromagnetic semiconductors

    Science.gov (United States)

    Ohno, Hideo

    2007-03-01

    Low magnetization (˜0.05 T) and high spin-polarization in ferromagnetism of transition metal-doped GaAs allow us to explore a number of spin-dependent phenomena not readily accessible in metal ferromagnets. Spin-polarized current induced domain wall (DW) motion in (Ga,Mn)As [1, 2] reveals rich physics resulting from the interaction between spin-polarized electrons and localized spins inside a magnetic DW. By using a 30 nm thick (Ga,Mn)As layer (xMn = 0.045) with perpendicular magnetic anisotropy, we have measured by magneto-optical Kerr microscopy a wide range of velocity-current density curves in the sample temperature range of 97 -- 107 K. Two regimes are found in the current density dependence of the DW velocity. At high-current densities (> 2 x 10^5 A/cm^2), the domain wall velocity is approximately a linear function of the current density above a threshold current density. This result will be compared to the recent theories of DW motion. At low-current densities, the functional form of the velocity-current curves follow an empirical scaling law, obtained by modifying the one for magnetic-field induced creep. This shows that current-induced DW creep is present. We have also determined the intrinsic resistance of the DW in a similar configuration [3]. *M. Yamanouchi, D. Chiba, F. Matsukura, and H. Ohno, Nature 428, 539 (2004). *M. Yamanouchi, D. Chiba, F. Matsukura, T. Dietl and H. Ohno, Phys. Rev. Lett. 96, 096601 (2006). *D. Chiba, M. Yamanouchi, F. Matsukura, T. Dietl, and H. Ohno, Phys. Rev. Lett. 96, 096602 (2006).

  5. Controlled motion of domain walls in submicron amorphous wires

    Directory of Open Access Journals (Sweden)

    Mihai Ţibu

    2016-05-01

    Full Text Available Results on the control of the domain wall displacement in cylindrical Fe77.5Si7.5B15 amorphous glass-coated submicron wires prepared by rapid quenching from the melt are reported. The control methods have relied on conical notches with various depths, up to a few tens of nm, made in the glass coating and in the metallic nucleus using a focused ion beam (FIB system, and on the use of small nucleation coils at one of the sample ends in order to apply magnetic field pulses aimed to enhance the nucleation of reverse domains. The notch-based method is used for the first time in the case of cylindrical ultrathin wires. The results show that the most efficient technique of controlling the domain wall motion in this type of samples is the simultaneous use of notches and nucleation coils. Their effect depends on wire diameter, notch depth, its position on the wire length, and characteristics of the applied pulse.

  6. Nonverbal synchrony and affect in dyadic interactions.

    Science.gov (United States)

    Tschacher, Wolfgang; Rees, Georg M; Ramseyer, Fabian

    2014-01-01

    In an experiment on dyadic social interaction, we invited participants to verbal interactions in cooperative, competitive, and 'fun task' conditions. We focused on the link between interactants' affectivity and their nonverbal synchrony, and explored which further variables contributed to affectivity: interactants' personality traits, sex, and the prescribed interaction tasks. Nonverbal synchrony was quantified by the coordination of interactants' body movement, using an automated video-analysis algorithm (motion energy analysis). Traits were assessed with standard questionnaires of personality, attachment, interactional style, psychopathology, and interpersonal reactivity. We included 168 previously unacquainted individuals who were randomly allocated to same-sex dyads (84 females, 84 males, mean age 27.8 years). Dyads discussed four topics of general interest drawn from an urn of eight topics, and finally engaged in a fun interaction. Each interaction lasted 5 min. In between interactions, participants repeatedly assessed their affect. Using hierarchical linear modeling, we found moderate to strong effect sizes for synchrony to occur, especially in competitive and fun task conditions. Positive affect was associated positively with synchrony, negative affect was associated negatively. As for causal direction, data supported the interpretation that synchrony entailed affect rather than vice versa. The link between nonverbal synchrony and affect was strongest in female dyads. The findings extend previous reports of synchrony and mimicry associated with emotion in relationships and suggest a possible mechanism of the synchrony-affect correlation.

  7. Nonverbal synchrony and affect in dyadic interactions

    Directory of Open Access Journals (Sweden)

    Wolfgang eTschacher

    2014-11-01

    Full Text Available In an experiment on dyadic social interaction, we invited participants to verbal interactions in cooperative, competitive, and 'fun task' conditions. We focused on the link between interactants' affectivity and their nonverbal synchrony, and explored which further variables contributed to affectivity: interactants' personality traits, sex, and the prescribed interaction tasks. Nonverbal synchrony was quantified by the coordination of interactants' body movement, using an automated video-analysis algorithm (Motion Energy Analysis, MEA. Traits were assessed with standard questionnaires of personality, attachment, interactional style, psychopathology and interpersonal reactivity. We included 168 previously unacquainted individuals who were randomly allocated to same-sex dyads (84 females, 84 males, mean age 27.3 years. Dyads discussed four topics of general interest drawn from an urn of eight topics, and finally engaged in a fun interaction. Each interaction lasted five minutes. In between interactions, participants repeatedly assessed their affect. Using hierarchical linear modeling, we found moderate to strong effect sizes for synchrony to occur, especially in competitive and fun task conditions. Positive affect was associated positively with synchrony, negative affect was associated negatively. As for causal direction, data supported the interpretation that synchrony entailed affect rather than vice versa. The link between nonverbal synchrony and affect was strongest in female dyads. The findings extend previous reports of synchrony and mimicry associated with emotion in relationships and suggest a possible mechanism of the synchrony-affect correlation.

  8. Chest Wall Motion during Speech Production in Patients with Advanced Ankylosing Spondylitis

    Science.gov (United States)

    Kalliakosta, Georgia; Mandros, Charalampos; Tzelepis, George E.

    2007-01-01

    Purpose: To test the hypothesis that ankylosing spondylitis (AS) alters the pattern of chest wall motion during speech production. Method: The pattern of chest wall motion during speech was measured with respiratory inductive plethysmography in 6 participants with advanced AS (5 men, 1 woman, age 45 plus or minus 8 years, Schober test 1.45 plus or…

  9. Electric-field-controlled suppression of Walker breakdown and chirality switching in magnetic domain wall motion

    Science.gov (United States)

    Chen, Hong-Bo; Li, You-Quan

    2016-07-01

    We theoretically study the dynamics of a magnetic domain wall controlled by an electric field in the presence of the spin flexoelectric interaction. We reveal that this interaction generates an effective spin torque and results in significant changes in the current-driven domain wall motion. In particular, the electric field can stabilize the domain wall motion, leading to strong suppression of the current-induced Walker breakdown and thus allowing a higher maximum wall velocity. We can furthermore use this electric-field control to efficiently switch the chirality of a moving domain wall in the steady regime.

  10. Antiferromagnetic domain wall motion driven by spin-orbit torques

    Science.gov (United States)

    Shiino, Takayuki; Oh, Se-Hyeok; Haney, Paul M.; Lee, Seo-Won; Go, Gyungchoon; Park, Byong-Guk; Lee, Kyung-Jin

    2016-01-01

    We theoretically investigate dynamics of antiferromagnetic domain walls driven by spin-orbit torques in antiferromagnet/heavy metal bilayers. We show that spin-orbit torques drive antiferromagnetic domain walls much faster than ferromagnetic domain walls. As the domain wall velocity approaches the maximum spin-wave group velocity, the domain wall undergoes Lorentz contraction and emits spin-waves in the terahertz frequency range. The interplay between spin-orbit torques and the relativistic dynamics of antiferromagnetic domain walls leads to the efficient manipulation of antiferromagnetic spin textures and paves the way for the generation of high frequency signals from antiferromagnets. PMID:27588878

  11. Current-driven magnetic domain wall motion and its real-time detection

    Science.gov (United States)

    Kim, Kab-Jin; Yoshimura, Yoko; Ono, Teruo

    2017-08-01

    Current-controlled magnetic domain wall motion has opened the possibility of a novel type of shift register memory device, which has been optimistically predicted to replace existing magnetic memories. Owing to this promising prospect, intensive work has been carried out during the last few decades. In this article, we first review the progress in the study of current-induced magnetic domain wall motion. Underlying mechanisms behind the domain wall motion, which have been discovered during last few decades, as well as technological achievements are presented. We then present our recent experimental results on the real-time detection of current-driven multiple magnetic domain wall motion, which directly demonstrates the operation of a magnetic domain wall shift register.

  12. Abdominal compliance, parasternal activation, and chest wall motion.

    Science.gov (United States)

    Cala, S J; Edyvean, J; Engel, L A

    1993-03-01

    We measured abdominal compliance (Cab) and rib cage displacement (delta Vrc) relative to abdominal displacement (delta Vab) during relaxation and tidal breathing in upright (U) and supine (S) postures in five normal subjects. In S, an abdominal binder was used to decrease Cab in two to five increments. We also measured the electrical activity of the parasternal muscle (EMGps) with the use of fine-wire intramuscular electrodes during CO2 rebreathing in U and in supine unbound (SU) and supine bound (SB) postures. During maximum binding (SB2), Cab decreased to 39 +/- 7% of the SU value (P = 0.01), matching Cab in U (P = 0.16). In the SB condition, the ratio of tidal delta Vrc/delta Vab to relaxation delta Vrc/delta Vab increased as Cab decreased, matching the data in U. For the group, this ratio decreased during SU to 47 +/- 10% (P = 0.02) but increased during SB2 to 86 +/- 7% (P = 0.18) of the value in U. During CO2 rebreathing, EMGps increased linearly with tidal volume (r > 0.727, P < 0.01). However, at any given tidal volume, the SU and SB2 EMGps were not significantly different (P = 0.12), and both were less than that in U (P < 0.02). The results suggest that the differences in chest wall motion between U and S may be due to the difference in Cab and not to different patterns of respiratory muscle recruitment. The mechanism may relate to changes in mechanical coupling between the diaphragm and the rib cage.

  13. Coupled Néel domain wall motion in sandwiched perpendicular magnetic anisotropy nanowires

    OpenAIRE

    Purnama, I.; Kerk, I. S.; Lim, G J; Lew, W. S.

    2015-01-01

    The operating performance of a domain wall-based magnetic device relies on the controlled motion of the domain walls within the ferromagnetic nanowires. Here, we report on the dynamics of coupled Néel domain wall in perpendicular magnetic anisotropy (PMA) nanowires via micromagnetic simulations. The coupled Néel domain wall is obtained in a sandwich structure, where two PMA nanowires that are separated by an insulating layer are stacked vertically. Under the application of high current densit...

  14. Analysis of intracranial aneurysm wall motion and its effects on hemodynamic patterns

    Science.gov (United States)

    Oubel, Estanislao; De Craene, Mathieu; Putman, Christopher M.; Cebral, Juan R.; Frangi, Alejandro F.

    2007-03-01

    Hemodynamics, and in particular Wall Shear Stress (WSS), is thought to play a critical role in the progression and rupture of intracranial aneurysms. Wall motion is related to local biomechanical properties of the aneurysm, which in turn are associated with the amount of damage undergone by the tissue. The underlying hypothesis in this work is that injured regions show differential motion with respect to normal ones, allowing a connection between local wall biomechanics and a potential mechanism of wall injury such as elevated WSS. In a previous work, a novel method was presented combining wall motion estimation using image registration techniques with Computational Fluid Dynamics (CFD) simulations in order to provide realistic intra-aneurysmal flow patterns. It was shown that, when compared to compliant vessels, rigid models tend to overestimate WSS and produce smaller areas of elevated WSS and force concentration, being the observed differences related to the magnitude of the displacements. This work aims to further study the relationships between wall motion, flow patterns and risk of rupture in aneurysms. To this end, four studies containing both 3DRA and DSA studies were analyzed, and an improved version of the method developed previously was applied to cases showing wall motion. A quantification and analysis of the displacement fields and their relationships to flow patterns are presented. This relationship may play an important role in understanding interaction mechanisms between hemodynamics, wall biomechanics, and the effect on aneurysm evolution mechanisms.

  15. Unstable equilibrium point in chaotic domain-wall motion and Ott-Grebogi-Yorke control

    Science.gov (United States)

    Okuno, H.; Takemura, Y.

    2001-06-01

    A method for finding the unstable equilibrium points in Bloch wall motion is proposed, which is important for controlling the chaotic domain-wall motion by using the Ott-Grebogi-Yorke (OGY) method. The dynamics of Bloch wall motion are expressed by a nonlinear differential equation with the terms of inertia, damping, restoring, and an external magnetic drive force. An equation is transformed into the difference equations by following the OGY method, approximating linearly around an unstable equilibrium point (a saddle point), and adding a controlling input. The unstable equilibrium points are obtained by using the return map and the condition of hyperbolic fixed point. The time series of domain-wall motion successfully controlled on the unstable equilibrium points by the OGY method is shown.

  16. Pattern recognition of abnormal left ventricle wall motion in cardiac MR.

    Science.gov (United States)

    Lu, Yingli; Radau, Perry; Connelly, Kim; Dick, Alexander; Wright, Graham

    2009-01-01

    There are four main problems that limit application of pattern recognition techniques for recognition of abnormal cardiac left ventricle (LV) wall motion: (1) Normalization of the LV's size, shape, intensity level and position; (2) defining a spatial correspondence between phases and subjects; (3) extracting features; (4) and discriminating abnormal from normal wall motion. Solving these four problems is required for application of pattern recognition techniques to classify the normal and abnormal LV wall motion. In this work, we introduce a normalization scheme to solve the first and second problems. With this scheme, LVs are normalized to the same position, size, and intensity level. Using the normalized images, we proposed an intra-segment classification criterion based on a correlation measure to solve the third and fourth problems. Application of the method to recognition of abnormal cardiac MR LV wall motion showed promising results.

  17. [Changes in left ventricular regional wall motion induced by Verapamil (author's transl)].

    Science.gov (United States)

    Barbieri, E; Allegri, P; Morlino, T; Vincenzi, M

    1980-01-01

    28 subjects with atherosclerotic lesions of coronary arteries were studied by means of cineventriculography both before and after IV administration of verapamil Regional wall motion has been analyzed by means of two different methods. Imporvement of regional wall motion has been demonstrated in about 65% of cases. No significant result has been achieved in segments corresponding to previous infarctions. Such a response does not differ substantially from that evoked by nitroglycerin or other calcium antagonist drugs.

  18. Domain wall motion driven by spin Hall effect—Tuning with in-plane magnetic anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Rushforth, A. W., E-mail: andrew.rushforth@nottingham.ac.uk [School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom)

    2014-04-21

    This letter investigates the effects of in-plane magnetic anisotropy on the current induced motion of magnetic domain walls in systems with dominant perpendicular magnetic anisotropy, where accumulated spins from the spin Hall effect in an adjacent heavy metal layer are responsible for driving the domain wall motion. It is found that that the sign and magnitude of the domain wall velocity in the uniform flow regime can be tuned significantly by the in-plane magnetic anisotropy. These effects are sensitive to the ratio of the adiabatic and non-adiabatic spin transfer torque parameters and are robust in the presence of pinning and thermal fluctuations.

  19. Manipulating antiferromagnets with magnetic fields: Ratchet motion of multiple domain walls induced by asymmetric field pulses

    Science.gov (United States)

    Gomonay, O.; Kläui, M.; Sinova, J.

    2016-10-01

    Future applications of antiferromagnets (AFs) in many spintronics devices rely on the precise manipulation of domain walls. The conventional approach using static magnetic fields is inefficient due to the low susceptibility of AFs. Recently proposed electrical manipulation with spin-orbit torques is restricted to metals with a specific crystal structure. Here, we propose an alternative, broadly applicable approach: using asymmetric magnetic field pulses to induce controlled ratchet motion of AF domain walls. The efficiency of this approach is based on three peculiarities of AF dynamics. First, a time-dependent magnetic field couples with an AF order parameter stronger than a static magnetic field, which leads to higher mobility of the domain walls. Second, the rate of change of the magnetic field couples with the spatial variation of the AF order parameter inside the domain, and this enables a synchronous motion of multiple domain walls with the same structure. Third, tailored asymmetric field pulses in combination with static friction can prevent backward motion of domain walls and thus lead to the desired controlled ratchet effect. The proposed use of an external field, rather than internal spin-orbit torques, avoids any restrictions on size, conductivity, and crystal structure of the AF material. We believe that our approach paves a way for the development of AF-based devices based on the controlled motion of AF domain walls.

  20. Ab initio study of edge effect on relative motion of walls in carbon nanotubes.

    Science.gov (United States)

    Popov, Andrey M; Lebedeva, Irina V; Knizhnik, Andrey A; Lozovik, Yurii E; Potapkin, Boris V

    2013-01-14

    Interwall interaction energies of double-walled nanotubes with long inner and short outer walls are calculated as functions of coordinates describing relative rotation and displacement of the walls using van der Waals corrected density functional theory. The magnitude of corrugation and the shape of the potential energy relief are found to be very sensitive to changes of the shorter wall length at subnanometer scale and atomic structure of the edges if at least one of the walls is chiral. Threshold forces required to start relative motion of the short walls and temperatures at which the transition between diffusive and free motion of the short walls takes place are estimated. The edges are also shown to provide a considerable contribution to the barrier to relative rotation of commensurate nonchiral walls. For such walls, temperatures of orientational melting, i.e., the crossover from rotational diffusion to free relative rotation, are estimated. The possibility to produce nanotube-based bolt∕nut pairs and nanobearings is discussed.

  1. Coupled Néel domain wall motion in sandwiched perpendicular magnetic anisotropy nanowires.

    Science.gov (United States)

    Purnama, I; Kerk, I S; Lim, G J; Lew, W S

    2015-03-04

    The operating performance of a domain wall-based magnetic device relies on the controlled motion of the domain walls within the ferromagnetic nanowires. Here, we report on the dynamics of coupled Néel domain wall in perpendicular magnetic anisotropy (PMA) nanowires via micromagnetic simulations. The coupled Néel domain wall is obtained in a sandwich structure, where two PMA nanowires that are separated by an insulating layer are stacked vertically. Under the application of high current density, we found that the Walker breakdown phenomenon is suppressed in the sandwich structure. Consequently, the coupled Néel domain wall of the sandwich structure is able to move faster as compared to individual domain walls in a single PMA nanowire.

  2. Domain wall motion by the magnonic spin Seebeck effect.

    Science.gov (United States)

    Hinzke, D; Nowak, U

    2011-07-08

    The recently discovered spin Seebeck effect refers to a spin current induced by a temperature gradient in a ferromagnetic material. It combines spin degrees of freedom with caloric properties, opening the door for the invention of new, spin caloritronic devices. Using spin model simulations as well as an innovative, multiscale micromagnetic framework we show that magnonic spin currents caused by temperature gradients lead to spin transfer torque effects, which can drag a domain wall in a ferromagnetic nanostructure towards the hotter part of the wire. This effect opens new perspectives for the control and manipulation of domain structures.

  3. Normal left ventricular wall motion measured with two-dimensional myocardial tagging

    DEFF Research Database (Denmark)

    Qi, P; Thomsen, C; Ståhlberg, F;

    1993-01-01

    Using a myocardial tagging technique, normal left ventricular wall motion was studied in 3 true short axis views and a double oblique 4-chamber view in 14 and 11 volunteers, respectively. Three orthogonal directions of left ventricular motion were observed throughout the systole; a concentric...... contraction towards the center of the left ventricle, a motion of the base of the heart towards the apex, and a rotation of the left ventricle around its long axis. The direction of left ventricular rotation changed from early systole to late systole. The base and middle levels of the left ventricle rotated...... that MR imaging with myocardial tagging is a method that can be used to study normal left ventricular wall motion, and that is promising for future use in patient groups....

  4. Effect of Joule heating in current-driven domain wall motion

    OpenAIRE

    A., Yamaguchi; S., Nasu; H., Tanigawa; T., Ono; K., Miyake; Ko, Mibu; T., Shinjo

    2004-01-01

    It was found that high current density needed for the current-driven domain wall motion results in the Joule heating of the sample. The sample temperature, when the current-driven domain wall motion occurred, was estimated by measuring the sample resistance during the application of a pulsed current. The sample temperature was 750 K for the threshold current density of 6.7×1011 A/m2 in a 10-nm-thick Ni81Fe19 wire with a width of 240 nm on thermally oxidized silicon substrate. The temperature ...

  5. Effect of Joule heating in current-driven domain wall motion

    OpenAIRE

    Yamaguchi, A.; Tanigawa, H.; Ono, T.; Nasu, S; Miyake, K.; Mibu, K.; Shinjo, T.

    2004-01-01

    It was found that high current density needed for the current-driven domain wall motion results in the Joule heating of the sample. The sample temperature, when the current-driven domain wall motion occurred, was estimated by measuring the sample resistance during the application of a pulsed-current. The sample temperature was 750 K for the threshold current density of 6.7 x 10^11 A/m2 in a 10 nm-thick Ni81Fe19 wire with a width of 240 nm. The temperature was raised to 830 K for the current d...

  6. MOTION AND DEFORMATION OF VISCOUS DROP IN STOKES FLOW NEAR RIGID WALL

    Institute of Scientific and Technical Information of China (English)

    LU Hua-jian; ZHANG Hui-sheng

    2005-01-01

    A boundary integral method was developed for simulating the motion and deformation of a viscous drop in an axisymmetric ambient Stokes flow near a rigid wall and for direct calculating the stress on the wall. Numerical experiments by the method were performed for different initial stand-off distances of the drop to the wall, viscosity ratios, combined surface tension and buoyancy parameters and ambient flow parameters. Numerical results show that due to the action of ambient flow and buoyancy the drop is compressed and stretched respectively in axial and radial directions when time goes. When the ambient flow action is weaker than that of the buoyancy the drop raises and bends upward and the stress on the wall induced by drop motion decreases when time advances. When the ambient flow action is stronger than that of the buoyancy the drop descends and becomes flatter and flatter as time goes. In this case when the initial stand-off distance is large the stress on the wall increases as the drop evolutes but when the stand-off distance is small the stress on the wall decreases as a result of combined effects of ambient flow, buoyancy and the stronger wall action to the flow. The action of the stress on the wall induced by drop motion is restricted in an area near the symmetric axis, which increases when the initial stand-off distance increases.When the initial stand-off distance increases the stress induced by drop motion decreases substantially. The surface tension effects resist the deformation and smooth the profile of the drop surfaces. The drop viscosity will reduce the deformation and migration of the drop.

  7. Domain wall motions in perpendicularly magnetized CoFe/Pd multilayer nanowire

    DEFF Research Database (Denmark)

    Meng, Zhaoliang; Kumar, Manoj; Qiu, Jinjun;

    2014-01-01

    Current-induced domain wall (DW) motion is investigated in a 600nm wide nanowire using multilayer film with a structure of Ta(5nm)/Pd(5nm)/[CoFe(0.4nm)/Pd(1.2nm)]15/Ta(5nm) in terms of anomalous Hall effect measurements. It is found that motion of DWs can be driven by a current density as low as 1...

  8. Automated classification of wall motion abnormalities by principal component analysis of endocardial shape motion patterns in echocardiograms

    Science.gov (United States)

    Bosch, Johan G.; Nijland, Francisca; Mitchell, Steven C.; Lelieveldt, Boudewijn P. F.; Kamp, Otto; Sonka, Milan; Reiber, Johan H. C.

    2003-05-01

    Principal Component Analysis of sets of temporal shape sequences renders eigenvariations of shape/motion, including typical normal and pathological endocardial contraction patterns. A previously developed Active Appearance Model for time sequences (AAMM) was employed to derive AAMM shape coefficients (ASCs) and we hypothesized these would allow classification of wall motion abnormalities (WMA). A set of stress echocardiograms (single-beat 4-chamber and 2-chamber sequences with expert-verified endocardial contours) of 129 infarct patients was split randomly into training (n=65) and testing (n=64) sets. AAMMs were generated from the training set and for all sequences ASCs were extracted and statistically related to regional/global Visual Wall Motion Scoring (VWMS) and clinical infarct severity and volumetric parameters. Linear regression showed clear correlations between ASCs and VWMS. Infarct severity measures correlated poorly to both ASCs and VWMS. Discriminant analysis showed good prediction from low #ASCs of both segmental (85% correctness) and global WMA (90% correctness). Volumetric parameters correlated poorly to regional VWMS. Conclusions: 1)ASCs show promising accuracy for automated WMA classification. 2)VWMS and endocardial border motion are closely related; with accurate automated border detection, automated WMA classification should be feasible. 3)ASC shape analysis allows contour set evaluation by direct comparison to clinical parameters.

  9. Echocardiographic Wall Motion Abnormality in Posterior Myocardial Infarction: The Diagnostic Value of Posterior Leads

    Directory of Open Access Journals (Sweden)

    A Darehzereshki

    2008-06-01

    Full Text Available Background: For the purpose of ascertaining myocardial infarction (MI and ischemia, the sensitivity of the initial 12-lead ECG is inadequate. It is risky to diagnose posterior MI using only precordial reciprocal changes, since the other leads may be more optimally positioned for the identification of electrocardiographic changes. In this study, we evaluated the relationship between electrocardiography changes and wall motion abnormalities in patients with posterior MI for earlier and better diagnosis of posterior MI.Methods: In this prospective cross-sectional study, we enrolled patients with posterior MI who had come to the Emergency Department of Shariati Hospital with their first episode of chest pain. A 12-lead surface electrocardiogram using posterior leads (V7-V9 was performed for all participants. Patients with ST elevation >0.05 mV or pathologic Q wave in the posterior leads, as well as those with specific changes indicating posterior MI in V1-V2, were evaluated by echocardiography in terms of wall motion abnormalities. All data were analyzed using SPSS and p<0.05 were considered statistically significant.Results: Of a total 79 patients enrolled, 48 (60.8% were men, and the mean age was 57.35±8.22 years. Smoking (54.4% and diabetes (48% were the most prevalent risk factors. In the echocardiographic evaluation, all patients had wall motion abnormalities in the left ventricle and 19 patients (24.1% had wall motion abnormalities in the right ventricle. The most frequent segment with motion abnormality among the all patients was the mid-posterior. The posterior leads showed better positive predictive value than the anterior leads for posterior wall motion abnormality.Conclusion: Electrocardiography of the posterior leads in patients with acute chest pain can help in earlier diagnosis and in time treatment of posterior MI.

  10. Modulated Magnetic Nanowires for Controlling Domain Wall Motion: Toward 3D Magnetic Memories

    KAUST Repository

    Ivanov, Yurii P.

    2016-05-03

    Cylindrical magnetic nanowires are attractive materials for next generation data storage devices owing to the theoretically achievable high domain wall velocity and their efficient fabrication in highly dense arrays. In order to obtain control over domain wall motion, reliable and well-defined pinning sites are required. Here, we show that modulated nanowires consisting of alternating nickel and cobalt sections facilitate efficient domain wall pinning at the interfaces of those sections. By combining electron holography with micromagnetic simulations, the pinning effect can be explained by the interaction of the stray fields generated at the interface and the domain wall. Utilizing a modified differential phase contrast imaging, we visualized the pinned domain wall with a high resolution, revealing its three-dimensional vortex structure with the previously predicted Bloch point at its center. These findings suggest the potential of modulated nanowires for the development of high-density, three-dimensional data storage devices. © 2016 American Chemical Society.

  11. Numerical Simulation of Microcarrier Motion in a Rotating Wall Vessel Bioreactor

    Institute of Scientific and Technical Information of China (English)

    ZHI-HAO JU; TIAN-QING LIU; XUE-HU MA; ZHAN-FENG CUI

    2006-01-01

    Objective To analyze the forces of rotational wall vessel (RWV) bioreactor on small tissue pieces or microcarrier particles and to determine the tracks of microcarrier particles in RWV bioreactor. Methods The motion of the microcarrier in the rotating wall vessel (RWV) bioreactor with both the inner and outer cylinders rotating was modeled by numerical simulation. Results The continuous trajectory of microcarrier particles, including the possible collision with the wall was obtained. An expression between the minimum rotational speed difference of the inner and outer cylinders and the microcarrier particle or aggregate radius could avoid collisions with either wall. The range of microcarrier radius or tissue size, which could be safely cultured in the RWV bioreactor, in terms of shear stress level, was determined. Conclusion The model works well in describing the trajectory of a heavier microcarrier particle in rotating wall vessel.

  12. Magnetic domain wall motion in notch patterned permalloy nanowire devices

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Ting-Chieh; Kuo, Cheng-Yi; Mishra, Amit K.; Das, Bipul; Wu, Jong-Ching, E-mail: phjcwu@cc.ncue.edu.tw

    2015-11-01

    We report a study of magnetization reversal process of notch-patterned permalloy (Py) nanowires (NWs) by using an in-situ magnetic force microscopy (MFM). Three neighboring straight NWs and an individual straight NW with discs connected to the wires ends are fabricated by standard electron beam lithography through a lift-off technique. MFM images are taken in the presence of an in-plane magnetic field applied along the wires length. As a result, the nucleation, pinning and depinning of domain walls (DWs) along the NW are observed. The artificial constraints (notch) in such symmetrical geometry of NWs indeed serve as pinning sites to pin the DWs. The nature of magnetization reversal, pinning field and depinning field for the DWs that are observed in these permalloy NWs, indicate the key roles of notch depth, the terminal connection structure of NW end and the inter-wire interaction among the NWs. The in-situ MFM measurements are examined with the micromagnetic simulations. Consequently, good agreements are obtained for the DW structures and the effect of DWs pining/depinning, however a dissimilarity in experimental and simulation observations for the direction of propagation of DWs in NWs needs further investigation.

  13. Distance-from-the-wall scaling of turbulent motions in wall-bounded flows

    Science.gov (United States)

    Baidya, R.; Philip, J.; Hutchins, N.; Monty, J. P.; Marusic, I.

    2017-02-01

    An assessment of self-similarity in the inertial sublayer is presented by considering the wall-normal velocity, in addition to the streamwise velocity component. The novelty of the current work lies in the inclusion of the second velocity component, made possible by carefully conducted subminiature ×-probe experiments to minimise the errors in measuring the wall-normal velocity. We show that not all turbulent stress quantities approach the self-similar asymptotic state at an equal rate as the Reynolds number is increased, with the Reynolds shear stress approaching faster than the streamwise normal stress. These trends are explained by the contributions from attached eddies. Furthermore, the Reynolds shear stress cospectra, through its scaling with the distance from the wall, are used to assess the wall-normal limits where self-similarity applies within the wall-bounded flow. The results are found to be consistent with the recent prediction from the work of Wei et al. ["Properties of the mean momentum balance in turbulent boundary layer, pipe and channel flows," J. Fluid Mech. 522, 303-327 (2005)], Klewicki ["Reynolds number dependence, scaling, and dynamics of turbulent boundary layers," J. Fluids Eng. 132, 094001 (2010)], and others that the self-similar region starts and ends at z+˜O (√{δ+}) and O (δ+) , respectively. Below the self-similar region, empirical evidence suggests that eddies responsible for turbulent stresses begin to exhibit distance-from-the-wall scaling at a fixed z+ location; however, they are distorted by viscous forces, which remain a leading order contribution in the mean momentum balance in the region z+≲O (√{δ+}) , and thus result in a departure from self-similarity.

  14. Nonmonotonic effects of perpendicular magnetic anisotropy on current-driven vortex wall motions in magnetic nanostripes

    Science.gov (United States)

    Su, Yuan-Chang; Lei, Hai-Yang; Hu, Jing-Guo

    2015-09-01

    In a magnetic nanostripe, the effects of perpendicular magnetic anisotropy (PMA) on the current-driven horizontal motion of vortex wall along the stripe and the vertical motion of the vortex core are studied by micromagnetic simulations. The results show that the horizontal and vertical motion can generally be monotonously enhanced by PMA. However, when the current is small, a nonmonotonic phenomenon for the horizontal motion is found. Namely, the velocity of the horizontal motion firstly decreases and then increases with the increase of the PMA. We find that the reason for this is that the PMA can firstly increase and then decrease the confining force induced by the confining potential energy. In addition, the PMA always enhances the driving force induced by the current. Project supported by the National Natural Science Foundation of China (Grant Nos. 11247026 and 11374253).

  15. Simulation and signal processing of through wall UWB radar for human being's periodic motions detection

    Science.gov (United States)

    Li, Jing; Liu, Fengshan; Xu, Penglong; Zeng, Zhaofa

    2013-05-01

    The human's Micro-Doppler signatures resulting from breathing, arm, foot and other periodic motion can provide valuable information about the structure of the moving parts and may be used for identification and classification purposes. In this paper, we carry out simulate with FDTD method and through wall experiment with UWB radar for human being's periodic motion detection. In addition, Advancements signal processing methods are presented to classify and to extract the human's periodic motion characteristic information, such as Micro-Doppler shift and motion frequency. Firstly, we apply the Principal Component Analysis (PCA) with singular value decomposition (SVD) to denoise and extract the human motion signal. Then, we present the results base on the Hilbert-Huang transform (HHT) and the S transform to classify and to identify the human's micro-Doppler shift characteristics. The results demonstrate that the combination of UWB radar and various processing methods has potential to detect human's Doppler signatures effectively.

  16. Field-driven Domain Wall Motion in Ferromagnetic Nanowires with Bulk Dzyaloshinskii-Moriya Interaction

    Science.gov (United States)

    Zhuo, Fengjun; Sun, Z. Z.

    2016-01-01

    Field-driven domain wall (DW) motion in ferromagnetic nanowires with easy- and hard-axis anisotropies was studied theoretically and numerically in the presence of the bulk Dzyaloshinskii-Moriya interaction (DMI) based on the Landau-Lifshitz-Gilbert equation. We propose a new trial function and offer an exact solution for DW motion along a uniaxial nanowire driven by an external magnetic field. A new strategy was suggested to speed up DW motion in a uniaxial magnetic nanowire with large DMI parameters. In the presence of hard-axis anisotropy, we find that the breakdown field and velocity of DW motion was strongly affected by the strength and sign of the DMI parameter under external fields. This work may be useful for future magnetic information storage devices based on DW motion. PMID:27118064

  17. Rapid estimation of left ventricular ejection fraction in acute myocardial infarction by echocardiographic wall motion analysis

    DEFF Research Database (Denmark)

    Berning, J; Rokkedal Nielsen, J; Launbjerg, J

    1992-01-01

    Echocardiographic estimates of left ventricular ejection fraction (ECHO-LVEF) in acute myocardial infarction (AMI) were obtained by a new approach, using visual analysis of left ventricular wall motion in a nine-segment model. The method was validated in 41 patients using radionuclide...

  18. Impairment of left ventricular regional wall motion in diabetes mellitus without coronary artery disease

    Energy Technology Data Exchange (ETDEWEB)

    Sakamoto, Ken`ya; Shimonagata, Tuyoshi; Nanto, Shinsuke; Kuroda, Akio; Morozumi, Takakazu; Kamado, Kenji; Nagata, Seiki [Kansai Rosai Hospital, Amagasaki, Hyogo (Japan); Yamasaki, Yoshimitsu

    1996-09-01

    To elucidate the mechanisms of diabetic cardiomyopathy, dual SPECT imaging with thallium-201 (Tl-201) and I-123 beta-methyl-p-iodophenyl pentadecanoic acid (BMIPP), a branched analogue of free fatty acid (FFA), and dipyridamole-infusion Tl-201 scintigraphy were performed in 28 NIDDM patients without coronary artery disease. Twenty eight patients were divided into two groups based on the presence of wall motion abnormalities on cineangiographic left ventriculography (LVG). Nineteen patients with normal wall motion documented on LVG (group A) out of 28 evaluated patients demonstrated normal Tl-201 and I-123 BMIPP uptake in dual SPECT imaging, whereas 9 patients with reduced wall motion (group B) demonstrated reduced I-123 BMIPP uptake when compared with Tl-201 uptake. On dipyridamole-infusion Tl-201 scintigraphy, transient perfusion defects were demonstrated in 4 patients of group B and two patients of group A (p<0.05). These results suggest that small vessel disease and the impairment of myocardial free fatty acid metabolism are etiologic or contributory factors for regional wall motion abnormality in diabetic cardiomyopathy. (author)

  19. Acute myocarditis with normal wall motion detected with 2D speckle tracking echocardiography

    Directory of Open Access Journals (Sweden)

    Thomas Sturmberger

    2016-05-01

    Full Text Available We present the case of a 26-year-old male with acute tonsillitis who was referred for coronary angiography because of chest pain, elevated cardiac biomarkers, and biphasic T waves. The patient had no cardiovascular risk factors. Echocardiography showed no wall motion abnormalities and no pericardial effusion. 2D speckle tracking revealed distinct decreased regional peak longitudinal systolic strain in the lateral and posterior walls. Ischemic disease was extremely unlikely in view of his young age, negative family history regarding coronary artery disease, and lack of regional wall motion abnormalities on the conventional 2D echocardiogram. Coronary angiography was deferred as myocarditis was suspected. To confirm the diagnosis, cardiac magnetic resonance tomography (MRT was performed, showing subepicardial delayed hyperenhancement in the lateral and posterior walls correlating closely with the strain pattern obtained by 2D speckle tracking echocardiography. With a working diagnosis of acute myocarditis associated with acute tonsillitis, we prescribed antibiotics and nonsteroidal anti-inflammatory drugs. The patient’s clinical signs resolved along with normalization of serum creatine kinase (CK levels, and the patient was discharged on the third day after admission. Learning points: • Acute myocarditis can mimic acute coronary syndromes. • Conventional 2D echocardiography lacks specific features for detection of subtle regional wall motion abnormalities. • 2D speckle tracking expands the scope of echocardiography in identifying myocardial dysfunction derived from edema in acute myocarditis.

  20. New techniques for the assessment of regional left ventricular wall motion.

    Science.gov (United States)

    Garcia-Fernandez, Miguel Angel; Bermejo, Javier; Perez-David, Esther; Lopez-Fernandez, Teresa; Ledesma, Maria Jesus; Caso, Pio; Malpica, Norberto; Santos, Andres; Moreno, Mar; Desco, Manuel

    2003-10-01

    The assessment of regional left ventricular (LV) function has been an important yet unresolved problem since the introduction of echocardiography as a diagnostic tool. Abnormal regional LV wall motion is an early finding in multiple cardiac pathologies and its diagnosis is of critical importance. In the last few years diagnostic procedures based on combined use of existing echocardiographic technologies were geared toward improving the accuracy of detection of baseline and/or induced regional wall motion abnormalities. One of the assumptions is that the combination of reduced LV wall thickening and reduced myocardial velocities can be used to accurately diagnose regional myocardial dysfunction. In this article we will discuss several new techniques for the quantification of regional LV function using Doppler echocardiography.

  1. Domain Wall Motion in Magnetic Nanostrips under the Influence of Rashba Field

    Directory of Open Access Journals (Sweden)

    Vito Puliafito

    2012-01-01

    Full Text Available Spin-orbit Rashba effect applies a torque on the magnetization of a ferromagnetic nanostrip in the case of structural inversion asymmetry, also affecting the steady domain wall motion induced by a spin-polarized current. This influence is here analytically studied in the framework of the extended Landau-Lifshitz-Gilbert equation, including the Rashba effect as an additive term of the effective field. Results of previous micromagnetic simulations and experiments have shown that this field yields an increased value of the Walker breakdown current together with an enlargement of the domain wall width. In order to analytically describe these results, the standard travelling wave ansatz for the steady domain wall motion is here adopted. Results of our investigations reveal the impossibility to reproduce, at the same time, the previous features and suggest the need of a more sophisticated model whose development requires, in turn, additional information to be extracted from ad hoc micromagnetic simulations.

  2. Effects of impurity transport and melt layer motion to the tungsten wall erosion during anomaly events

    Energy Technology Data Exchange (ETDEWEB)

    Ibano, K., E-mail: kibano@eei.eng.osaka-u.ac.jp; Tsutsui, T.; Lang, T.L.; Togo, S.; Ogawa, Y.

    2015-08-15

    Developing designs of future fusion devices, safety and soundness of the rector at anomaly events must be ensured. A computational approach is being taken by developing a homegrown integrated reactor simulation code and analyzing a loss-of-cooling-gas-puff accident (LCGA). This code currently includes simple plasma, edge, and wall models. In this study, models for the tungsten transport and melt layer motion was added and used for the analysis. It was found that this accident results significant erosion of the wall while impurities from the wall would contribute the radiation cooling for the intense heat flux. However, these effects strongly depend on an uncertain parameter of the tungsten transport as well as the tungsten melt layer motion. Thus, parametric survey for these uncertain quantities were taken and discussed.

  3. Domain wall motion and Barkhausen effect in magnetic nanoparticles for EOR applications

    Science.gov (United States)

    Baig, Mirza Khurram; Soleimani, Hassan; Yahya, Noorhana

    2016-11-01

    The domain wall motion in magnetic nanoparticles is a useful parameter of study. The subject of this research is to study of the phenomenon of discontinuous domain wall motion, or the Barkhausen Effect in magnetic nanoparticles. In this work hematite (Fe2O3) nanoparticles have been synthesized using sol-gel auto-combustion and characterized using X-ray diffraction, Field emission scanning electron microscopy (FESEM), Transmission electron microscope (TEM) and Vibrating sample magnetometer (VSM) for crystal structure, morphology, shape, size and magnetic properties respectively. The FESEM and TEM results show that the particles are spherical in nature and average size is 60nm that is suitable for domain walls and barkhuasen effect. The VSM results show high coercivity 175 Oe and low saturation magnetization due to domain wall pinning and barkhausen effect. The size and magnetic properties reveals the existence of domain walls in the synthesized sample. The magnetic properties confirm the energy losses due to domain wall pinning, discontinuous domain rotation or barkhausen effect during magnetization which is useful for oil-water interfacial tension reduction and viscosity of oil. The high surface charge of magnetic nanoparticles and adsorption at the rock surface is useful for wettability alteration of rocks.

  4. Current-driven vortex domain wall motion in wire-tube nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Espejo, A. P. [Departamento de Física, Universidad de Santiago de Chile (USACH), Av. Ecuador 3493, 9170124 Santiago (Chile); Institute of Nanostructure and Solid State Physics, University of Hamburg, Jungiusstrasse 11, D-20355 Hamburg (Germany); Vidal-Silva, N. [Departamento de Física, Universidad de Santiago de Chile (USACH), Av. Ecuador 3493, 9170124 Santiago (Chile); López-López, J. A. [Departamento de Física, Universidad Técnica Federico Santa María, Av. España 1680, Valparaíso (Chile); Goerlitz, D.; Nielsch, K. [Institute of Nanostructure and Solid State Physics, University of Hamburg, Jungiusstrasse 11, D-20355 Hamburg (Germany); Escrig, J. [Departamento de Física, Universidad de Santiago de Chile (USACH), Av. Ecuador 3493, 9170124 Santiago (Chile); Center for the Development of Nanoscience and Nanotechnology (CEDENNA), Av. Ecuador 3493, 9170124 Santiago (Chile)

    2015-03-30

    We have investigated the current-driven domain wall motion in nanostructures comprised of a pair of nanotube and nanowire segments. Under certain values of external magnetic fields, it is possible to pin a vortex domain wall in the transition zone between the wire and tube segments. We explored the behavior of this domain wall under the action of an electron flow applied in the opposite direction to the magnetic field. Thus, for a fixed magnetic field, it is possible to release a domain wall pinned simply by increasing the intensity of the current density, or conversely, for a fixed current density, it is possible to release the domain wall simply decreasing the magnetic external field. When the domain wall remains pinned due to the competition between the current density and the magnetic external field, it exhibits a oscillation frequency close to 8 GHz. The amplitude of the oscillations increases with the current density and decreases over time. On the other hand, when the domain wall is released and propagated through the tube segment, this shows the standard separation between a steady and a precessional regime. The ability to pin and release a domain wall by varying the geometric parameters, the current density, or the magnetic field transforms these wire-tube nanostructures in an interesting alternative as an on/off switch nano-transistor.

  5. Micromagnetic analysis of current-driven domain wall motion of multi-bit in a nanowire with perpendicular magnetic anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Murakami, Hiroshi; Takahashi, Kouta; Komine, Takashi; Sugita, Ryuji, E-mail: komine@mx.ibaraki.ac.j [4-12-1 Nakanarusawa, Hitachi, Ibaraki 316-8511, Ibaraki University (Japan)

    2010-01-01

    The current-driven domain wall motion of a multi-bit in a magnetic nanowire with perpendicular magnetic anisotropy has been analyzed by performing a micromagnetic simulation. The multi-bit motion is determined by the applied current density and the non-adiabatic spin torque parameters, which is similar to the current-driven domain wall motion of the single wall. Consequently, it was found that are two modes in the multi-bit motion: (a) the bit length remains constant and (b) the bit length varies or the bit vanishes in the nanowire. It was found that these modes of the multi-bit motion can be classified by the critical current density or Walker breakdown for the single wall motion in a magnetic nanowire with perpendicular magnetic anisotropy.

  6. Current driven domain wall motion in rare-earth transition metal alloys with perpendicular magnetic anisotropy.

    Science.gov (United States)

    Li, Songtian; Liu, Xiaoxi; Morisako, Akimistu

    2012-09-01

    The domain wall movement behaviors under current combining with magnetic field in perpendicularly magnetized TbFeCo wire were studied by a polar magneto-optical Kerr effect microscope. The velocity for domain wall creeping along electrons flowing direction was found to be apparently higher than that of domain wall creeping against electrons flowing, which is the signature of the spin transfer torque effect. By employing the modified field-driven creep motion law, a spin transfer efficiency of 2.7 Oe cm2/10(6) A was determined for TbFeCo wire by treating the spin transfer torque as an effective field adding to the external field. The high spin transfer efficiency suggests that perpendicularly magnetized system with sharp domain walls in TbFeCo film shows high superiorities for applications in spin transfer torque based devices compared with in-plane magnetized systems.

  7. Simultaneous effects of slip and wall properties on MHD peristaltic motion of nanofluid with Joule heating

    Energy Technology Data Exchange (ETDEWEB)

    Hayat, T. [Department of Mathematics, Quaid-I-Azam University 45320, Islamabad 44000 (Pakistan); Nonlinear Analysis and Applied Mathematics (NAAM) Research Group, Department of Mathematics, King Abdulaziz University, P.O. Box 80257, Jeddah 21589 (Saudi Arabia); Nisar, Z. [Department of Mathematics, Quaid-I-Azam University 45320, Islamabad 44000 (Pakistan); Ahmad, B. [Nonlinear Analysis and Applied Mathematics (NAAM) Research Group, Department of Mathematics, King Abdulaziz University, P.O. Box 80257, Jeddah 21589 (Saudi Arabia); Yasmin, H., E-mail: qau2011@gmail.com [Department of Mathematics, COMSATS Institute of Information Technology, G.T. Road, Wah Cantt 47040 (Pakistan)

    2015-12-01

    This paper is devoted to the magnetohydrodynamic (MHD) peristaltic transport of nanofluid in a channel with wall properties. Flow analysis is addressed in the presence of viscous dissipation, partial slip and Joule heating effects. Mathematical modelling also includes the salient features of Brownian motion and thermophoresis. Both analytic and numerical solutions are provided. Comparison between the solutions is shown in a very good agreement. Attention is focused to the Brownian motion parameter, thermophoresis parameter, Hartman number, Eckert number and Prandtl number. Influences of various parameters on skin friction coefficient, Nusselt and Sherwood numbers are also investigated. It is found that both the temperature and nanoparticles concentration are increasing functions of Brownian motion and thermophoresis parameters. - Highlights: • Temperature rises when Brownian motion and thermophoresis effects intensify. • Temperature profile increases when thermal slip parameter increases. • Concentration field is a decreasing function of concentration slip parameter. • Temperature decreases whereas concentration increases for Hartman number.

  8. A method to quantitate regional wall motion in left ventriculography using Hildreth algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Terashima, Mikio [Hyogo Red Cross Blood Center (Japan); Naito, Hiroaki; Sato, Yoshinobu; Tamura, Shinichi; Kurosawa, Tsutomu

    1998-06-01

    Quantitative measurement of ventricular wall motion is indispensable for objective evaluation of cardiac function associated with coronary artery disease. We have modified the Hildreth`s algorithm to estimate excursions of the ventricular wall on left ventricular images yielded by various imaging techniques. Tagging cine-MRI was carried out on 7 healthy volunteers. The original Hildreth method, the modified Hildreth method and the centerline method were applied to the outlines of the images obtained, to estimate excursion of the left ventricular wall and regional shortening and to evaluate the accuracy of these methods when measuring these parameters, compared to the values of these parameters measured actually using the attached tags. The accuracy of the original Hildreth method was comparable to that of the centerline method, while the modified Hildreth method was significantly more accurate than the centerline method (P<0.05). Regional shortening as estimated using the modified Hildreth method differed less from the actually measured regional shortening than did the shortening estimated using the centerline method (P<0.05). The modified Hildreth method allowed reasonable estimation of left ventricular wall excursion in all cases where it was applied. These results indicate that when applied to left ventriculograms for ventricular wall motion analysis, the modified Hildreth method is more useful than the original Hildreth method. (author)

  9. Analysis of Human's Motions Based on Local Mean Decomposition in Through-wall Radar Detection

    Science.gov (United States)

    Lu, Qi; Liu, Cai; Zeng, Zhaofa; Li, Jing; Zhang, Xuebing

    2016-04-01

    Observation of human motions through a wall is an important issue in security applications and search-and rescue. Radar has advantages in looking through walls where other sensors give low performance or cannot be used at all. Ultrawideband (UWB) radar has high spatial resolution as a result of employment of ultranarrow pulses. It has abilities to distinguish the closely positioned targets and provide time-lapse information of targets. Moreover, the UWB radar shows good performance in wall penetration when the inherently short pulses spread their energy over a broad frequency range. Human's motions show periodic features including respiration, swing arms and legs, fluctuations of the torso. Detection of human targets is based on the fact that there is always periodic motion due to breathing or other body movements like walking. The radar can gain the reflections from each human body parts and add the reflections at each time sample. The periodic movements will cause micro-Doppler modulation in the reflected radar signals. Time-frequency analysis methods are consider as the effective tools to analysis and extract micro-Doppler effects caused by the periodic movements in the reflected radar signal, such as short-time Fourier transform (STFT), wavelet transform (WT), and Hilbert-Huang transform (HHT).The local mean decomposition (LMD), initially developed by Smith (2005), is to decomposed amplitude and frequency modulated signals into a small set of product functions (PFs), each of which is the product of an envelope signal and a frequency modulated signal from which a time-vary instantaneous phase and instantaneous frequency can be derived. As bypassing the Hilbert transform, the LMD has no demodulation error coming from window effect and involves no negative frequency without physical sense. Also, the instantaneous attributes obtained by LMD are more stable and precise than those obtained by the empirical mode decomposition (EMD) because LMD uses smoothed local

  10. Dynamic radionuclide determination of regional left ventricular wall motion using a new digital imaging device

    Science.gov (United States)

    Steele, P.; Kirch, D.

    1975-01-01

    In 47 men with arteriographically defined coronary artery disease comparative studies of left ventricular ejection fraction and segmental wall motion were made with radionuclide data obtained from the image intensifier camera computer system and with contrast cineventriculography. The radionuclide data was digitized and the images corresponding to left ventricular end-diastole and end-systole were identified from the left ventricular time-activity curve. The left ventricular end-diastolic and end-systolic images were subtracted to form a silhouette difference image which described wall motion of the anterior and inferior left ventricular segments. The image intensifier camera allows manipulation of dynamically acquired radionuclide data because of the high count rate and consequently improved resolution of the left ventricular image.

  11. Current induced domain wall motion in nanostripes with perpendicular magnetic anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Noh, Su Jung; Tan, Reasmey P.; Chun, Byong Sun [Department of Materials Science and Engineering, Korea University, Seoul 136-713 (Korea, Republic of); Kim, Young Keun, E-mail: ykim97@korea.ac.k [Department of Materials Science and Engineering, Korea University, Seoul 136-713 (Korea, Republic of)

    2010-11-15

    We report micromagnetic modeling results of current induced domain wall (DW) motion in magnetic devices with perpendicular magnetic anisotropy by solving the Landau-Lifschitz-Gilbert equation including adiabatic and non-adiabatic terms. A nanostripe model system with dimensions of 500 nm (L)x25 nm (W)x5 nm (H) was selected for calculating the DW motion and its width, as a function of various parameters such as non-adiabatic contribution, anisotropy constant (K{sub u}), saturation magnetization (M{sub s}), and temperature (T). The DW velocity was found to increase when the values of K{sub u} and T were increased and the M{sub s} value decreased. In addition, a reduction of the domain wall width could be achieved by increasing K{sub u} and lowering M{sub s} values regardless of the non-adiabatic constant value.

  12. Motion of a particle between two parallel plane walls in low-Reynolds-number Poiseuille flow

    Science.gov (United States)

    Staben, Michelle E.; Zinchenko, Alexander Z.; Davis, Robert H.

    2003-06-01

    A new boundary-integral algorithm for the motion of a particle between two parallel plane walls in Poiseuille flow at low Reynolds number was developed to study the translational and rotational velocities for a broad range of particle sizes and depths in the channel. Instead of the free-space Green's function more commonly employed in boundary-integral equations, we used the Green's function for the domain between two infinite plane walls [Liron and Mochon, J. Eng. Math. 10, 287 (1976)]. This formulation allows us to directly incorporate the effects of the wall interactions into the stress tensor, without discretizing the bounding walls, and use well-established iterative methods. Our results are in good agreement with previous computations [Ganatos et al., J. Fluid Mech. 99, 755 (1980)] and limiting cases, over their range of application, with additional results obtained for very small particle-wall separations of less than 1% of the particle radius. In addition to the boundary-integral solution in the mobility formulation, we used the resistance formulation to derive the near-field asymptotic forms for the translational and rotational velocities, extending the results to even smaller particle-wall separations. The decrease in translational velocity from the unperturbed fluid velocity increases with particle size and proximity of the particle to one or both of the walls. The rotational velocity exhibits a maximum magnitude between the centerline and either wall, due to the competing influences of wall retardation and the greater fluid velocity gradient near the walls. The average particle velocity for a uniform distribution of particles was generally found to exceed the average fluid velocity, due in large part to exclusion of the particle centers from the region of slowest fluid near the walls. The maximum average particle velocity is 18% greater than the average fluid velocity and occurs for particle diameters that are 42% of the channel height; particles with

  13. Color structured light system of chest wall motion measurement for respiratory volume evaluation.

    Science.gov (United States)

    Chen, Huijun; Cheng, Yuan; Liu, Dongdong; Zhang, Xiaodong; Zhang, Jue; Que, Chengli; Wang, Guangfa; Fang, Jing

    2010-01-01

    We present a structured light system to dynamically measure human chest wall motion for respiratory volume estimation. Based on a projection of an encoded color pattern and a few active markers attached to the trunk, respiratory volumes are obtained by evaluating the 3-D topographic changes of the chest wall in an anatomically consistent measuring region during respiration. Three measuring setups are established: a single-sided illuminating-recording setup for standing posture, an inclined single-sided setup for supine posture, and a double-sided setup for standing posture. Results are compared with the pneumotachography and show good agreement in volume estimations [correlation coefficient: R>0.99 (Pevaluation with high accuracy, but also regional pulmonary function assessment in different chest wall behaviors, with the advantage of whole-field measurement.

  14. Influence of exchange coupling on current-driven domain wall motion in a nanowire

    Energy Technology Data Exchange (ETDEWEB)

    Komine, Takashi, E-mail: komine@mx.ibaraki.ac.j [Department of Media and Telecommunications Engineering, Ibaraki University, Ibaraki 316-8511 (Japan); Takahashi, Kota; Murakami, Hiroshi; Sugita, Ryuji [Department of Media and Telecommunications Engineering, Ibaraki University, Ibaraki 316-8511 (Japan)

    2010-10-15

    In this study, the effect of exchange stiffness constant on current-driven domain wall motion in nanowires with in-plane magnetic anisotropy (IMA) and perpendicular magnetic anisotropy (PMA) has been investigated using micromagnetic simulation. The critical current density in a nanowire with IMA decreases as the exchange stiffness constant decreases because the domain wall width at the upper edge of the nanowire narrows according to the decrease of the exchange stiffness constant. On the other hand, the critical current density in a nanowire with PMA slightly decreases contrary to that of IMA although the domain wall width reasonably decreases as the exchange stiffness constant decreases. The slight reduction rate of the critical current density is due to the increase of the effective hard-axis anisotropy of PMA nanowire.

  15. Heart wall motion analysis by dynamic 3D strain rate imaging from tissue Doppler echocardiography

    Science.gov (United States)

    Hastenteufel, Mark; Wolf, Ivo; de Simone, Raffaele; Mottl-Link, Sibylle; Meinzer, Hans-Peter

    2002-04-01

    The knowledge about the complex three-dimensional (3D) heart wall motion pattern, particular in the left ventricle, provides valuable information about potential malfunctions, e.g., myocardial ischemia. Nowadays, echocardiography (cardiac ultrasound) is the predominant technique for evaluation of cardiac function. Beside morphology, tissue velocities can be obtained by Doppler techniques (tissue Doppler imaging, TDI). Strain rate imaging (SRI) is a new technique to diagnose heart vitality. It provides information about the contraction ability of the myocardium. Two-dimensional color Doppler echocardiography is still the most important clinical method for estimation of morphology and function. Two-dimensional methods leads to a lack of information due to the three-dimensional overall nature of the heart movement. Due to this complex three-dimensional motion pattern of the heart, the knowledge about velocity and strain rate distribution over the whole ventricle can provide more valuable diagnostic information about motion disorders. For the assessment of intracardiac blood flow three-dimensional color Doppler has already shown its clinical utility. We have developed methods to produce strain rate images by means of 3D tissue Doppler echocardiography. The tissue Doppler and strain rate images can be visualized and quantified by different methods. The methods are integrated into an interactively usable software environment, making them available in clinical everyday life. Our software provides the physician with a valuable tool for diagnosis of heart wall motion.

  16. Simultaneous effects of slip and wall properties on MHD peristaltic motion of nanofluid with Joule heating

    Science.gov (United States)

    Hayat, T.; Nisar, Z.; Ahmad, B.; Yasmin, H.

    2015-12-01

    This paper is devoted to the magnetohydrodynamic (MHD) peristaltic transport of nanofluid in a channel with wall properties. Flow analysis is addressed in the presence of viscous dissipation, partial slip and Joule heating effects. Mathematical modelling also includes the salient features of Brownian motion and thermophoresis. Both analytic and numerical solutions are provided. Comparison between the solutions is shown in a very good agreement. Attention is focused to the Brownian motion parameter, thermophoresis parameter, Hartman number, Eckert number and Prandtl number. Influences of various parameters on skin friction coefficient, Nusselt and Sherwood numbers are also investigated. It is found that both the temperature and nanoparticles concentration are increasing functions of Brownian motion and thermophoresis parameters.

  17. Evaluation of regional wall motion in myocardial infarction using animation ECG gated cardiac computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Shimizu, Takahiko; Hyodo, Haruo; Hayashi, Terumi; Yamamoto, Hideo; Yagi, Shigeru

    1984-08-01

    Regional wall motion of the left ventricle was evaluated in 21 patients with myocardial infarction using an animation system of gated cardiac computed tomographic (CT) images (animation gated CCT). The results obtained were compared with data by two-dimensional echocardiography (2-DE). 1. Evaluation of the asynergic area by animation gated CCT and 2-DE: Animation gated CCT detected the following specific regions with asynergy established by 2-DE; 10/10 cases (100%) at the anterior wall of the left ventricle, 14/14 cases (100%) at the interventricular septum, and 9/11 cases (81.8%) at the infero-posterior wall. In addition, one false positive case and one negative case were observed at the lateral wall and the apex, respectively. Of 37 instances with asynergic areas established by 2-DE, 21 cases or 89.2% were detected by animation gated CCT; the sensitivity was 91.9%. 2. Evaluation of severity of asynergy by animation gated CCT and 2-DE: The degree of asynergy evaluated by both methods was compared with each other, and the agreement was as follows: 10/10 cases (100%) at the left-ventricular anterior wall, 13/13 cases (100%) at the interventricular septum, and 7/9 cases (77.8%) at the infero-posterior wall. 3. Evaluation of the asynergic area by nonanimation gated CCT and 2-DE: Nonanimation gated CCT detected asynergic areas ascertained by 2-DE at the following areas; 8/10 cases (80%) at the left-ventricular anterior wall, 12/14 cases (85.7%) at the interventricular septum, and 4/11 cases (36.4%) at the infero-posterior wall. The difference between animation and nonanimation gated CCT was statistically significant (p < 0.05). The severity of asynergy could not be evaluated by nonanimation gated CCT. (J.P.N.).

  18. Quantitative Evaluation of Left Ventricular Wall Motion in Patient with Coronary Artery Bypass Grafting Using Magnetic Resonance Tagging Technique

    Science.gov (United States)

    Inaba, Tadashi; Nakano, Takahiro; Tsutsumi, Masakazu; Kawasaki, Shingo; Kinosada, Yasutomi; Tokuda, Masataka

    Left ventricular wall motions during systole were investigated from a mechanical perspective by using a magnetic resonance tagging technique. Subjects were 7 patients with coronary artery bypass grafting (CABG). First, by analyzing strain in the left ventricular wall, cardiac contractility was evaluated in the patients with CABG. Next, by calculating displacement in the myocardial wall, paradoxical movements following CABG were quantitatively evaluated. Strain analysis showed local decreases in circumferential strain in 4 of 7 subjects. The results of displacement analysis clarified that following CABG, the degree of radial displacement was small in the septal wall and large in the lateral wall, and circumferential displacement towards the septal wall occurred in the anterior and posterior walls. Since this behavior was seen in both reduced and normal cardiac contractility groups, paradoxical movements in the present patients were not caused by reduced cardiac contractility, but rather by rigid-body motion of the entire heart.

  19. Left Ventricular Synchrony and Function in Pediatric Patients with Definitive Pacemakers

    Science.gov (United States)

    Ortega, Michel Cabrera; Morejón, Adel Eladio Gonzales; Ricardo, Giselle Serrano

    2013-01-01

    Background Chronic right ventricular pacing (RVP) induces a dyssynchronous contraction pattern, producing interventricular and intraventricular asynchrony. Many studies have shown the relationship of RVP with impaired left ventricular (LV) form and function. Objective The aim of this study was to evaluate LV synchrony and function in pediatric patients receiving RVP in comparison with those receiving LV pacing (LVP). Methods LV systolic and diastolic function and synchrony were evaluated in 80 pediatric patients with either nonsurgical or postsurgical complete atrioventricular block, with pacing from either the RV endocardium (n = 40) or the LV epicardium (n = 40). Echocardiographic data obtained before pacemaker implantation, immediately after it, and at the end of a mean follow-up of 6.8 years were analyzed. Results LV diastolic function did not change in any patient during follow-up. LV systolic function was preserved in patients with LVP. However, in children with RVP the shortening fraction and ejection fraction decreased from medians of 41% ± 2.6% and 70% ± 6.9% before implantation to 32% ± 4.2% and 64% ± 2.5% (p < 0.0001 and p < 0.0001), respectively, at final follow-up. Interventricular mechanical delay was significantly larger with RVP (66 ± 13 ms) than with LVP (20 ± 8 ms). Similarly, the following parameters were significantly different in the two groups: LV mechanical delay (RVP: 69 ± 6 ms, LVP: 30 ± 11 ms, p < 0.0001); septal to lateral wall motion delay (RVP: 75 ± 19 ms, LVP: 42 ± 10 ms, p < 0.0001); and, septal to posterior wall motion delay (RVP: 127 ± 33 ms, LVP: 58 ± 17 ms, p < 0.0001). Conclusion Compared with RV endocardium, LV epicardium is an optimal site for pacing to preserve cardiac synchrony and function. PMID:24061683

  20. Unstable equilibrium point in chaotic domain-wall motion and Ott{endash}Grebogi{endash}Yorke control

    Energy Technology Data Exchange (ETDEWEB)

    Okuno, H.; Takemura, Y.

    2001-06-01

    A method for finding the unstable equilibrium points in Bloch wall motion is proposed, which is important for controlling the chaotic domain-wall motion by using the Ott{endash}Grebogi{endash}Yorke (OGY) method. The dynamics of Bloch wall motion are expressed by a nonlinear differential equation with the terms of inertia, damping, restoring, and an external magnetic drive force. An equation is transformed into the difference equations by following the OGY method, approximating linearly around an unstable equilibrium point (a saddle point), and adding a controlling input. The unstable equilibrium points are obtained by using the return map and the condition of hyperbolic fixed point. The time series of domain-wall motion successfully controlled on the unstable equilibrium points by the OGY method is shown. {copyright} 2001 American Institute of Physics.

  1. Magnetic domain-wall motion twisted by nanoscale probe-induced spin transfer

    Science.gov (United States)

    Wang, J.; Xie, L. S.; Wang, C. S.; Zhang, H. Z.; Shu, L.; Bai, J.; Chai, Y. S.; Zhao, X.; Nie, J. C.; Cao, C. B.; Gu, C. Z.; Xiong, C. M.; Sun, Y.; Shi, J.; Salahuddin, S.; Xia, K.; Nan, C. W.; Zhang, J. X.

    2014-12-01

    A method for deterministic control of magnetism using an electrical stimulus is highly desired for the new generation of magnetoelectronic devices. Much effort has been focused on magnetic domain-wall (DW) motion manipulated by a successive injection of spin-polarized current into a magnetic nanostructure. However, an integrant high-threshold current density of 1011˜1012A /m2 inhibits the integration with low-energy-cost technology. Here, we report an approach to manipulate a single magnetic domain wall with a perpendicular anisotropy in a manganite/dielectric/metal capacitor using a probe-induced spin displacement. A spin-transfer torque (STT) occurs in the strongly correlated manganite film during the spin injection into the capacitor from the nanoscale magnetized tip with an ultralow voltage of 0.1 V, where a lower bound of the estimated threshold spin-polarized current density is ˜108A /m2 at the tip/manganite interface. The dynamic of DW motions are analyzed using the Landau-Lifshitz-Gilbert method. This probe-voltage-controlled DW motion, at an ambient condition, demonstrates a critical framework for the fundamental understanding of the manipulation of the nanomagnet systems with low-energy consumption.

  2. Assessment of left ventricular regional wall motion by color kinesis technique: comparison with angiographic findings.

    Science.gov (United States)

    Vermes, E; Guyon, P; Weingrod, M; Otmani, A; Soussana, C; Halphen, C; Leroy, G; Haïat, R

    2000-08-01

    The analysis of segmental wall motion using two-dimensional (2-D) echocardiography is subjective with high interobserver variability. Color kinesis is a new technique providing a color-encoded map of endocardial motion. We evaluated the accuracy of color kinesis and 2-D for assessment of regional asynergy compared with left ventricular angiography as a reference method. Fifteen patients admitted for myocardial infarction were studied by echocardiography the day before left ventricular angiography. The left ventricle was divided into seven segments. Each segment was classified by two independent observers as normal or abnormal in 2-D and color kinesis. Accuracy of color kinesis and 2-D was evaluated and compared to left ventricular angiography. Color kinesis is significantly superior to 2-D for all seven segments (mean 0.80/0.68, P = 0.05), except for the septum (0.67/0.60, P = NS). Interobserver variability studied by chi-square statistic is lower with color kinesis (0.70) than with 2-D (0.57). We conclude that these data suggest that color kinesis is a useful method for assessing systolic wall motion in all segments, except the septum and for improving the accuracy of segmental ventricular function and interobserver variability.

  3. Assessment of left ventricular wall motion abnormalities with the use of color kinesis: a valuable visual and training aid.

    Science.gov (United States)

    Lau, Y S; Puryear, J V; Gan, S C; Fowler, M B; Vagelos, R H; Popp, R L; Schnittger, I

    1997-01-01

    Accurate interpretation of left ventricular segmental wall motion by echocardiography is an important yet difficult skill to learn. Color-coded left ventricular wall motion (color kinesis) is a tool that potentially could aid in the interpretation and provide semiquantification. We studied the usefulness of color kinesis in 42 patients with a history of congestive cardiomyopathy who underwent two-dimensional echocardiograms and a color kinesis study. The expert's reading of the two-dimensional wall motion served as a reference for comparison of color kinesis studies interpreted by the expert and a cardiovascular trainee. Correlation between two-dimensional echocardiography and the expert's and trainee's color coded wall motion scores were r = 0.83 and r = 0.67, respectively. Reproducibility between reviewers and between operators was also assessed. Interobserver variability for color-coded wall motion showed a correlation of r = 0.78. Correlation between operators was also good; r = 0.84. Color kinesis is reliable and appears promising as an adjunct in the assessment of wall motion abnormalities by echocardiography. It is both a valuable visual aid, as well as a training aid for the cardiovascular trainee.

  4. Monitoring spike train synchrony

    CERN Document Server

    Kreuz, Thomas; Houghton, Conor; Andrzejak, Ralph G; Mormann, Florian

    2012-01-01

    Recently, the SPIKE-distance has been proposed as a parameter-free and time-scale independent measure of spike train synchrony. This measure is time-resolved since it relies on instantaneous estimates of spike train dissimilarity. However, its original definition led to spuriously high instantaneous values for event-like firing patterns. Here we present a substantial improvement of this measure which eliminates this shortcoming. The reliability gained allows us to track changes in instantaneous clustering, i.e., time-localized patterns of (dis)similarity among multiple spike trains. Additional new features include selective and triggered temporal averaging as well as the instantaneous comparison of spike train groups. In a second step, a causal SPIKE-distance is defined such that the instantaneous values of dissimilarity rely on past information only so that time-resolved spike train synchrony can be estimated in real-time. We demonstrate that these methods are capable of extracting valuable information from ...

  5. Temperature dependence of carrier spin polarization determined from current-induced domain wall motion in a Co/Ni nanowire

    Energy Technology Data Exchange (ETDEWEB)

    Ueda, K.; Koyama, T.; Hiramatsu, R.; Kobayashi, K.; Ono, T. [Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Chiba, D. [Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho Kawaguchi, Saitama 322-0012 (Japan); Fukami, S. [Green Innovation Research Laboratories, NEC Corporation, 34 Miyukigaoka, Tsukuba, Ibaraki 305-8501 (Japan); Center for Spintronics Integrated Systems, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Tanigawa, H.; Suzuki, T. [RENESAS Electronics Corporation, Sagamihara, Kanagawa 252-5298 (Japan); Ohshima, N. [NEC Energy Device Ltd., 1120 Shimokuzawa, Chuo-ku, Sagamihara, Kanagawa 252-5298 (Japan); Ishiwata, N. [Green Innovation Research Laboratories, NEC Corporation, 34 Miyukigaoka, Tsukuba, Ibaraki 305-8501 (Japan); Nakatani, Y. [University of Electro-communications, Chofu, Tokyo 182-8585 (Japan)

    2012-05-14

    We have investigated the temperature dependence of the current-induced magnetic domain wall (DW) motion in a perpendicularly magnetized Co/Ni nanowire at various temperatures and with various applied currents. The carrier spin polarization was estimated from the measured domain wall velocity. We found that it decreased more with increasing temperature from 100 K to 530 K than the saturation magnetization did.

  6. Neuronal synchrony 

    OpenAIRE

    Buzsáki, Gyorgy

    2010-01-01

    1. Neuronal synchrony: metabolic and wiring costs of excitatory and inhibitory systems The major part of the brain’s energy budget (~ 60-80%) is devoted to its communication activities. While inhibition is critical to brain function, relatively little attention has been paid to its metabolic costs. Understanding how inhibitory interneurons contribute to brain energy consumption (brain work) is not only of interest in understanding a fundamental aspect of brain function but also in understandi...

  7. Pectoralis Muscle Flap Repair Reduces Paradoxical Motion of the Chest Wall in Complex Sternal Wound Dehiscence

    Science.gov (United States)

    Zeitani, Jacob; Russo, Marco; Pompeo, Eugenio; Sergiacomi, Gian Luigi; Chiariello, Luigi

    2016-01-01

    Background The aim of the study was to test the hypothesis that in patients with chronic complex sternum dehiscence, the use of muscle flap repair minimizes the occurrence of paradoxical motion of the chest wall (CWPM) when compared to sternal rewiring, eventually leading to better respiratory function and clinical outcomes during follow-up. Methods In a propensity score matching analysis, out of 94 patients who underwent sternal reconstruction, 20 patients were selected: 10 patients underwent sternal reconstruction with bilateral pectoralis muscle flaps (group 1) and 10 underwent sternal rewiring (group 2). Eligibility criteria included the presence of hemisternum diastases associated with multiple (≥3) bone fractures and radiologic evidence of synchronous chest wall motion (CWSM). We compared radiologically assessed (volumetric computed tomography) ventilatory mechanic indices such as single lung and global vital capacity (VC), diaphragm excursion, synchronous and paradoxical chest wall motion. Results Follow-up was 100% complete (mean 85±24 months). CWPM was inversely correlated with single lung VC (Spearman R=−0.72, p=0.0003), global VC (R=−0.51, p=0.02) and diaphragm excursion (R=−0.80, p=0.0003), whereas it proved directly correlated with dyspnea grade (Spearman R=0.51, p=0.02) and pain (R=0.59, p=0.005). Mean CWPM and single lung VC were both better in group 1, whereas there was no difference in CWSM, diaphragm excursion and global VC. Conclusion Our study suggests that in patients with complex chronic sternal dehiscence, pectoralis muscle flap reconstruction guarantees lower CWPM and greater single-lung VC when compared with sternal rewiring and it is associated with better clinical outcomes with less pain and dyspnea. PMID:27733997

  8. Monitoring spike train synchrony.

    Science.gov (United States)

    Kreuz, Thomas; Chicharro, Daniel; Houghton, Conor; Andrzejak, Ralph G; Mormann, Florian

    2013-03-01

    Recently, the SPIKE-distance has been proposed as a parameter-free and timescale-independent measure of spike train synchrony. This measure is time resolved since it relies on instantaneous estimates of spike train dissimilarity. However, its original definition led to spuriously high instantaneous values for eventlike firing patterns. Here we present a substantial improvement of this measure that eliminates this shortcoming. The reliability gained allows us to track changes in instantaneous clustering, i.e., time-localized patterns of (dis)similarity among multiple spike trains. Additional new features include selective and triggered temporal averaging as well as the instantaneous comparison of spike train groups. In a second step, a causal SPIKE-distance is defined such that the instantaneous values of dissimilarity rely on past information only so that time-resolved spike train synchrony can be estimated in real time. We demonstrate that these methods are capable of extracting valuable information from field data by monitoring the synchrony between neuronal spike trains during an epileptic seizure. Finally, the applicability of both the regular and the real-time SPIKE-distance to continuous data is illustrated on model electroencephalographic (EEG) recordings.

  9. Solution of Two-Dimensional Viscous Flow Driven by Motion of Flexible Walls

    Directory of Open Access Journals (Sweden)

    Mohamed Gad-el-Hak

    2010-03-01

    Full Text Available An exact solution of the Navier–Stokes equations for a flow driven by motion of flexible wall is developed. A simple two-dimensional channel with deforming walls is considered as domain. The governing equations are linearized for low Reynolds number and large Womersley number Newtonian flows. Appropriate boundary conditions for general deformation are decomposed into harmonic excitations in space by Fourier series decomposition. A model of harmonic boundary deformation is considered and results are compared with computational fluid dynamics predictions. The results of velocity profiles across the channel and the centerline velocities of the channel are in good agreement with CFD solution. The analytical model developed provides quantitative descriptions of the flow field for a wide spectrum of actuating frequnecy and boundary conditions. The presented model can be used as an effective framework for preliminary design and optimization of displacement micropumps and other miniature applications.

  10. Influence of wall motion on particle sedimentation using hybrid LB-IBM scheme

    Science.gov (United States)

    Habte, Mussie A.; Wu, ChuiJie

    2017-03-01

    We integrate the lattice Boltzmann method (LBM) and immersed boundary method (IBM) to capture the coupling between a rigid boundary surface and the hydrodynamic response of an enclosed particle laden fluid. We focus on a rigid box filled with a Newtonian fluid where the drag force based on the slip velocity at the wall and settling particles induces the interaction. We impose an external harmonic oscillation on the system boundary and found interesting results in the sedimentation behavior. Our results reveal that the sedimentation and particle locations are sensitive to the boundary walls oscillation amplitude and the subsequent changes on the enclosed flow field. Two different particle distribution analyses were performed and showed the presence of an agglomerate structure of particles. Despite the increase in the amplitude of wall motion, the turbulence level of the flow field and distribution of particles are found to be less in quantity compared to the stationary walls. The integrated LBM-IBM methodology promised the prospect of an efficient and accurate dynamic coupling between a non-compliant bounding surface and flow field in a wide-range of systems. Understanding the dynamics of the fluid-filled box can be particularly important in a simulation of particle deposition within biological systems and other engineering applications.

  11. Two-dimensional simulation of red blood cell motion near a wall under a lateral force

    Science.gov (United States)

    Hariprasad, Daniel S.; Secomb, Timothy W.

    2014-11-01

    The motion of a red blood cell suspended in a linear shear flow adjacent to a fixed boundary subject to an applied lateral force directed toward the boundary is simulated. A two-dimensional model is used that represents the viscous and elastic properties of normal red blood cells. Shear rates in the range of 100 to 600 s-1 are considered, and the suspending medium viscosity is 1 cP. In the absence of a lateral force, the cell executes a tumbling motion. With increasing lateral force, a transition from tumbling to tank-treading is predicted. The minimum force required to ensure tank-treading increases nonlinearly with the shear rate. Transient swinging motions occur when the force is slightly larger than the transition value. The applied lateral force is balanced by a hydrodynamic lift force resulting from the positive orientation of the long axis of the cell with respect to the wall. In the case of cyclic tumbling motions, the orientation angle takes positive values through most of the cycle, resulting in lift generation. These results are used to predict the motion of a cell close to the outer edge of the cell-rich core region that is generated when blood flows in a narrow tube. In this case, the lateral force is generated by shear-induced dispersion, resulting from cell-cell interactions in a region with a concentration gradient. This force is estimated using previous data on shear-induced dispersion. The cell is predicted to execute tank-treading motions at normal physiological hematocrit levels, with the possibility of tumbling at lower hematocrit levels.

  12. Energy-efficient writing scheme for magnetic domain-wall motion memory

    Science.gov (United States)

    Kim, Kab-Jin; Yoshimura, Yoko; Ham, Woo Seung; Ernst, Rick; Hirata, Yuushou; Li, Tian; Kim, Sanghoon; Moriyama, Takahiro; Nakatani, Yoshinobu; Ono, Teruo

    2017-04-01

    We present an energy-efficient magnetic domain-writing scheme for domain wall (DW) motion-based memory devices. A cross-shaped nanowire is employed to inject a domain into the nanowire through current-induced DW propagation. The energy required for injecting the magnetic domain is more than one order of magnitude lower than that for the conventional field-based writing scheme. The proposed scheme is beneficial for device miniaturization because the threshold current for DW propagation scales with the device size, which cannot be achieved in the conventional field-based technique.

  13. Effect of Joule heating in current-driven domain wall motion

    Science.gov (United States)

    Yamaguchi, A.; Nasu, S.; Tanigawa, H.; Ono, T.; Miyake, K.; Mibu, K.; Shinjo, T.

    2005-01-01

    It was found that high current density needed for the current-driven domain wall motion results in the Joule heating of the sample. The sample temperature, when the current-driven domain wall motion occurred, was estimated by measuring the sample resistance during the application of a pulsed current. The sample temperature was 750 K for the threshold current density of 6.7×1011A/m2 in a 10-nm-thick Ni81Fe19 wire with a width of 240 nm on thermally oxidized silicon substrate. The temperature was raised to 830 K for the current density of 7.5×1011A/m2, which is very close to the Curie temperature of bulk Ni81Fe19. When the current density exceeded 7.5×1011A/m2, an appearance of a multidomain structure in the wire was observed by magnetic force microscopy, suggesting that the sample temperature exceeded the Curie temperature.

  14. Observation of hohlraum-wall motion with spectrally selective x-ray imaging at the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Izumi, N., E-mail: izumi2@llnl.gov; Meezan, N. B.; Divol, L.; Hall, G. N.; Barrios, M. A.; Jones, O.; Landen, O. L.; Kroll, J. J.; Vonhof, S. A.; Nikroo, A.; Bailey, C. G.; Hardy, C. M.; Ehrlich, R. B.; Town, R. P. J.; Bradley, D. K.; Hinkel, D. E.; Moody, J. D. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Jaquez, J. [General Atomics, San Diego, California 9212 (United States)

    2016-11-15

    The high fuel capsule compression required for indirect drive inertial confinement fusion requires careful control of the X-ray drive symmetry throughout the laser pulse. When the outer cone beams strike the hohlraum wall, the plasma ablated off the hohlraum wall expands into the hohlraum and can alter both the outer and inner cone beam propagations and hence the X-ray drive symmetry especially at the final stage of the drive pulse. To quantitatively understand the wall motion, we developed a new experimental technique which visualizes the expansion and stagnation of the hohlraum wall plasma. Details of the experiment and the technique of spectrally selective x-ray imaging are discussed.

  15. Observation of hohlraum-wall motion with spectrally selective x-ray imaging at the National Ignition Facility

    Science.gov (United States)

    Izumi, N.; Meezan, N. B.; Divol, L.; Hall, G. N.; Barrios, M. A.; Jones, O.; Landen, O. L.; Kroll, J. J.; Vonhof, S. A.; Nikroo, A.; Jaquez, J.; Bailey, C. G.; Hardy, C. M.; Ehrlich, R. B.; Town, R. P. J.; Bradley, D. K.; Hinkel, D. E.; Moody, J. D.

    2016-11-01

    The high fuel capsule compression required for indirect drive inertial confinement fusion requires careful control of the X-ray drive symmetry throughout the laser pulse. When the outer cone beams strike the hohlraum wall, the plasma ablated off the hohlraum wall expands into the hohlraum and can alter both the outer and inner cone beam propagations and hence the X-ray drive symmetry especially at the final stage of the drive pulse. To quantitatively understand the wall motion, we developed a new experimental technique which visualizes the expansion and stagnation of the hohlraum wall plasma. Details of the experiment and the technique of spectrally selective x-ray imaging are discussed.

  16. Role of spin diffusion in current-induced domain wall motion for disordered ferromagnets

    KAUST Repository

    Akosa, Collins Ashu

    2015-03-12

    Current-induced spin transfer torque and magnetization dynamics in the presence of spin diffusion in disordered magnetic textures is studied theoretically. We demonstrate using tight-binding calculations that weak, spin-conserving impurity scattering dramatically enhances the nonadiabaticity. To further explore this mechanism, a phenomenological drift-diffusion model for incoherent spin transport is investigated. We show that incoherent spin diffusion indeed produces an additional spatially dependent torque of the form ∼∇2[m×(u⋅∇)m]+ξ∇2[(u⋅∇)m], where m is the local magnetization direction, u is the direction of injected current, and ξ is a parameter characterizing the spin dynamics (precession, dephasing, and spin-flip). This torque, which scales as the inverse square of the domain wall width, only weakly enhances the longitudinal velocity of a transverse domain wall but significantly enhances the transverse velocity of vortex walls. The spatial-dependent spin transfer torque uncovered in this study is expected to have significant impact on the current-driven motion of abrupt two-dimensional textures such as vortices, skyrmions, and merons.

  17. Effect of microwaves on domain wall motion in thin Ni wires

    Science.gov (United States)

    Hong, Kimin; Giordano, N.

    1996-03-01

    We report new results on domain wall motion in thin (width and thickness ~ 300 ÅNi wires. The magnetoresistance exhibits discontinuities which we believe are associated with pinning and de-pinning of walls from structural defects, such as variations in the width of the sample. Upon repeated measurement, the de-pinning is found to occur over a narrow range of fields. The distribution of de-pinning fields, P(H), varies with temperature in a manner which suggests that de-pinning occurs via thermal activation at high temperatures, and quantum tunneling at low temperatures, with crossover between these two regimes at T ~ 2 - 6 K. We have also investigated the effect of a 30 GHz microwave field on P(H). In the thermal activation regime, microwaves have no effect on P(H), except through Joule heating. However, in the tunneling regime microwaves cause P(H) to split into several separate peaks. This behavior cannot be explained in terms of Joule heating, but suggests that the energy levels of a domain wall in a pinning well are quantized.

  18. Spatial synchrony in cisco recruitment

    Science.gov (United States)

    Myers, Jared T.; Yule, Daniel L.; Jones, Michael L.; Ahrenstorff, Tyler D.; Hrabik, Thomas R.; Claramunt, Randall M.; Ebener, Mark P.; Berglund, Eric K.

    2015-01-01

    We examined the spatial scale of recruitment variability for disparate cisco (Coregonus artedi) populations in the Great Lakes (n = 8) and Minnesota inland lakes (n = 4). We found that the scale of synchrony was approximately 400 km when all available data were utilized; much greater than the 50-km scale suggested for freshwater fish populations in an earlier global analysis. The presence of recruitment synchrony between Great Lakes and inland lake cisco populations supports the hypothesis that synchronicity is driven by climate and not dispersal. We also found synchrony in larval densities among three Lake Superior populations separated by 25–275 km, which further supports the hypothesis that broad-scale climatic factors are the cause of spatial synchrony. Among several candidate climate variables measured during the period of larval cisco emergence, maximum wind speeds exhibited the most similar spatial scale of synchrony to that observed for cisco. Other factors, such as average water temperatures, exhibited synchrony on broader spatial scales, which suggests they could also be contributing to recruitment synchrony. Our results provide evidence that abiotic factors can induce synchronous patterns of recruitment for populations of cisco inhabiting waters across a broad geographic range, and show that broad-scale synchrony of recruitment can occur in freshwater fish populations as well as those from marine systems.

  19. Prosocial Consequences of Interpersonal Synchrony

    Science.gov (United States)

    2016-01-01

    Abstract. The capacity to establish interpersonal synchrony is fundamental to human beings because it constitutes the basis for social connection and understanding. Interpersonal synchrony refers to instances when the movements or sensations of two or more people overlap in time and form. Recently, the causal influence of interpersonal synchrony on prosociality has been established through experiments. The current meta-analysis is the first to synthesize these isolated and sometimes contradictory experiments. We meta-analyzed 60 published and unpublished experiments that compared an interpersonal synchrony condition with at least one control condition. The results reveal a medium effect of interpersonal synchrony on prosociality with regard to both attitudes and behaviors. Furthermore, experimenter effects and intentionality moderate these effects. We discuss the strengths and limitations of our analysis, as well as its practical implications, and we suggest avenues for future research. PMID:28105388

  20. In-vivo quantification of wall motion in cerebral aneurysms from 2D cine phase contrast magnetic resonance images

    Energy Technology Data Exchange (ETDEWEB)

    Karmonik, C. [The Methodist Hospital Research Inst., Houston (United States); Diaz, O.; Klucznik, R. [The Methodist Hospital, Houston (United States); Grossman, R. [The Methodist Hospital, Houston (United States). Neurosurgery

    2010-02-15

    Purpose: The quantification of wall motion in cerebral aneurysms is of interest for the assessment of aneurysmal rupture risk, for providing boundary conditions for computational simulations and as a validation tool for theoretical models. Materials and Methods: 2D cine phase contrast magnetic resonance imaging (2D pcMRI) in combination with quantitative magnetic resonance angiography (QMRA) was evaluated for measuring wall motion in 7 intracranial aneurysms. In each aneurysm, 2 (in one case 3) cross sections, oriented approximately perpendicular to each other, were measured. Results: The maximum aneurysmal wall distention ranged from 0.16 mm to 1.6 mm (mean 0.67 mm), the maximum aneurysmal wall contraction was -1.91 mm to -0.34 mm (mean 0.94 mm), and the average wall displacement ranged from 0.04 mm to 0.31 mm (mean 0.15 mm). Statistically significant correlations between average wall displacement and the shape of inflow curves (p-value < 0.05) were found in 7 of 15 cross sections; statistically significant correlations between the displacement of the luminal boundary center point and the shape of inflow curves (p-value < 0.05) were found in 6 of 15 cross sections. Conclusion: 2D pcMRI in combination with QMRA is capable of visualizing and quantifying wall motion in cerebral aneurysms. However, application of this technique is currently restricted by its limited spatial resolution. (orig.)

  1. Micromagnetic modeling of domain wall motion in sub-100-nm-wide wires with individual and periodic edge defects

    Directory of Open Access Journals (Sweden)

    S. Dutta

    2015-12-01

    Full Text Available Reducing the switching energy of devices that rely on magnetic domain wall motion requires scaling the devices to widths well below 100 nm, where the nanowire line edge roughness (LER is an inherent source of domain wall pinning. We investigate the effects of periodic and isolated rectangular notches, triangular notches, changes in anisotropy, and roughness measured from images of fabricated wires, in sub-100-nm-wide nanowires with in-plane and perpendicular magnetic anisotropy using micromagnetic modeling. Pinning fields calculated for a model based on discretized images of physical wires are compared to experimental measurements. When the width of the domain wall is smaller than the notch period, the domain wall velocity is modulated as the domain wall propagates along the wire. We find that in sub-30-nm-wide wires, edge defects determine the operating threshold and domain wall dynamics.

  2. Easy moment direction and antiferromagnetic domain wall motion in Mn2Au

    Science.gov (United States)

    Barthem, Vitoria M. T. S.; Colin, Claire V.; Haettel, Richard; Dufeu, Didier; Givord, Dominique

    2016-05-01

    The interest of giving active functions to antiferromagnetic (AFM) materials in spintronics devices has been realized recently. Mn2Au is a high-Néel temperature antiferromagnet with large Mn moment, lying in plane of the tetragonal structure. To determine the direction of the moments in Mn2Au, an original approach is demonstrated, which should be generic to planar AFM materials. It involves the rotation of the granular sample around an axis perpendicular to the applied magnetic field. The family of easy moment directions is . For grains prevented from rotating, the dominant magnetization process is AFM domain wall motion. Textured Mn2Au nanoelements could be introduced in spintronics devices, in which the Mn moments would be switched under modest external excitation.

  3. Miniature Hall sensor integrated on a magnetic thin film for detecting domain wall motion

    Science.gov (United States)

    Kubota, M.; Tokunaga, Y.; Kanazawa, N.; Kagawa, F.; Tokura, Y.; Kawasaki, M.

    2013-08-01

    We have fabricated a cross-bar Hall sensor made of 50-nm-wide and 100-nm-thick bismuth wires patterned by an electron-beam lithography and lift-off. The Hall coefficient at 300 K is as large as -0.44 cm3/C, yielding in a high product sensitivity of about 5 V/(A T). The series resistance was reduced as low as 1.7 kΩ with a short bar configuration, resulting in a high signal-to-noise ratio of 38.5 dB. These characteristics are far better than those reported with similar dimensions. The Hall element was successfully demonstrated for detecting the domain wall motion in an iron garnet film employed as the substrate.

  4. Ring-shaped Racetrack memory based on spin orbit torque driven chiral domain wall motions

    Science.gov (United States)

    Zhang, Yue; Zhang, Xueying; Hu, Jingtong; Nan, Jiang; Zheng, Zhenyi; Zhang, Zhizhong; Zhang, Youguang; Vernier, Nicolas; Ravelosona, Dafine; Zhao, Weisheng

    2016-10-01

    Racetrack memory (RM) has sparked enormous interest thanks to its outstanding potential for low-power, high-density and high-speed data storage. However, since it requires bi-directional domain wall (DW) shifting process for outputting data, the mainstream stripe-shaped concept certainly suffers from the data overflow issue. This geometrical restriction leads to increasing complexity of peripheral circuits or programming as well as undesirable reliability issue. In this work, we propose and study ring-shaped RM, which is based on an alternative mechanism, spin orbit torque (SOT) driven chiral DW motions. Micromagnetic simulations have been carried out to validate its functionality and exhibit its performance advantages. The current flowing through the heavy metal instead of ferromagnetic layer realizes the “end to end” circulation of storage data, which remains all the data in the device even if they are shifted. It blazes a promising path for application of RM in practical memory and logic.

  5. Apical regional wall motion abnormalities reminiscent to Tako-Tsubo cardiomyopathy following consumption of psychoactive fungi.

    Science.gov (United States)

    Nef, Holger M; Möllmann, Helge; Hilpert, Pirmin; Krause, Nicola; Troidl, Christian; Weber, Michael; Rolf, Andreas; Dill, Thorsten; Hamm, Christian; Elsässer, A

    2009-05-01

    Consumption of natural hallucinogenic substances continues to be a problem. In this case we report from a young male patient presenting with an acute coronary syndrome with significant ST-elevation after the abuse of psychoactive fungi, commonly referred to as "magic mushrooms". Coronary angiography excludes relevant coronary artery disease. In ventriculography contractile dysfunction with hypokinesia in the apical segments could be documented reminiscent to wall motion abnormalities in Tako-Tsubo cardiomyopathy (TTC). Cardiovascular magnetic resonance imaging showed no pathological signal activity in the late-enhancement sequences ruling out myocardial infarction or inflammatory processes. Ventricular function normalized within several days. The active metabolite of psychoactive fungi psilocybin is known to interact with several different dopaminergic, adrenergic and serotonergic receptors. Thus, the pathomechanisms leading to contractile dysfunction after consumption of psychoactive fungi are reminiscent to those documented in TTC.

  6. Easy moment direction and antiferromagnetic domain wall motion in Mn{sub 2}Au

    Energy Technology Data Exchange (ETDEWEB)

    Barthem, Vitoria M.T.S. [Instituto de Fisica, Universidade Federal do Rio de Janeiro, Cidade Universitaria, Ilha do Fundao, 21941-972 Rio de Janeiro (Brazil); Colin, Claire V.; Haettel, Richard; Dufeu, Didier [Université Grenoble Alpes, Institut NEEL, 25 Avenue des Martyrs, BP 166, F-38042 Grenoble (France); CNRS, Institut NEEL, 25 Avenue des Martyrs, BP 166, F-38042 Grenoble (France); Givord, Dominique, E-mail: dominique.givord@neel.cnrs.fr [Instituto de Fisica, Universidade Federal do Rio de Janeiro, Cidade Universitaria, Ilha do Fundao, 21941-972 Rio de Janeiro (Brazil); Université Grenoble Alpes, Institut NEEL, 25 Avenue des Martyrs, BP 166, F-38042 Grenoble (France); CNRS, Institut NEEL, 25 Avenue des Martyrs, BP 166, F-38042 Grenoble (France)

    2016-05-15

    The interest of giving active functions to antiferromagnetic (AFM) materials in spintronics devices has been realized recently. Mn{sub 2}Au is a high-Néel temperature antiferromagnet with large Mn moment, lying in plane of the tetragonal structure. To determine the direction of the moments in Mn{sub 2}Au, an original approach is demonstrated, which should be generic to planar AFM materials. It involves the rotation of the granular sample around an axis perpendicular to the applied magnetic field. The family of easy moment directions is 〈110〉. For grains prevented from rotating, the dominant magnetization process is AFM domain wall motion. Textured Mn{sub 2}Au nanoelements could be introduced in spintronics devices, in which the Mn moments would be switched under modest external excitation.

  7. Magnetic domain wall motion in Co/Ni nanowires induced by a sloped electric field

    Science.gov (United States)

    Yamada, Keisuke; Murayama, Soh; Nakatani, Yoshinobu

    2016-05-01

    We report the sloped-electric-field (SEF)-driven motion of a magnetic domain wall (DW) in a Co/Ni nanowire with a perpendicular anisotropy using micromagnetic simulations. The results show that the DW velocity increases in proportion to the modulation ratio of the SEF, and rapidly decreases above a threshold ratio of SEF (i.e., the breakdown). We derived the analytical equation of the effective magnetic field caused by the SEF, and show the resultant DW velocity. Also, we found that the maximum DW velocity is three times faster when the Dzyaloshinskii-Moriya interaction is 0.06 erg/cm2. The results presented here offer a promising route for the design of non-volatile memory and logic devices using only the electric-field.

  8. Transient motion of and heat transfer in a rarefied gas between plane parallel walls with different surface properties

    Science.gov (United States)

    Doi, Toshiyuki

    2016-09-01

    Transient motion of and heat transfer in a rarefied gas between plane parallel walls with different surface properties are studied based on kinetic theory. It is assumed that one wall is a diffuse reflection boundary and the other wall is a Maxwell-type boundary, and the transient behavior of the gas caused by a sudden heating of one of the walls is studied. The linearized Boltzmann equation for a hard-sphere molecular gas is numerically studied using the modified hybrid scheme of the characteristic coordinate and finite difference methods, to correctly describe the discontinuities in the velocity distribution function. The transient motion of the gas from an early time stage to the final time-independent state is studied over a wide range of the mean free path and the accommodation coefficient of the boundary. Between the two transient flows caused by the heating of the respective walls, the values of the heat flow on the heated wall are different, whereas those on the unheated wall coincide identically. This property, which is a consequence of the symmetric relation of the linearized Boltzmann equation, is numerically confirmed over a wide range of the mean free path. The long time behavior of the heat flow on the walls is quite similar to that of the shear stress in the Couette flow problem, whereas a distinct wavy behavior is observed in an early time stage.

  9. Direct observation of current-induced motion of a 3D vortex domain wall in cylindrical nanowires

    KAUST Repository

    Ivanov, Yurii P.

    2017-05-08

    The current-induced dynamics of 3D magnetic vortex domain walls in cylindrical Co/Ni nanowires are revealed experimentally using Lorentz microscopy and theoretically using micromagnetic simulations. We demonstrate that a spin-polarized electric current can control the reversible motion of 3D vortex domain walls, which travel with a velocity of a few hundred meters per second. This finding is a key step in establishing fast, high-density memory devices based on vertical arrays of cylindrical magnetic nanowires.

  10. Cooperative Learning and Interpersonal Synchrony.

    Science.gov (United States)

    Vink, Roy; Wijnants, Maarten L; Cillessen, Antonius H N; Bosman, Anna M T

    2017-04-01

    Cooperative learning has been shown to result in better task performance, compared to individual and competitive learning, and can lead to positive social effects. However, potential working mechanisms at a micro level remain unexplored. One potential working mechanism might be the level of interpersonal synchrony between cooperating individuals. It has been shown that increased levels of interpersonal synchrony are related to better cognitive performance (e.g., increased memory). Social factors also appear to be affected by the level of interpersonal synchrony, with more interpersonal synchrony leading to increased likeability. In the present study, interpersonal synchrony of postural sway and its relation to task performance and social factors (i.e., popularity, social acceptance, and likeability) was examined. To test this, 183 dyads performed a tangram task while each child stood on a Nintendo Wii Balance Board that recorded their postural sway. The results showed that lower levels of interpersonal synchrony were related to better task performance and those dyads who were on average more popular synchronized more. These results contradict previous findings. It is suggested that for task performance, a more loosely coupled system is better than a synchronized system. In terms of social competence, dyad popularity was associated with more interpersonal synchrony.

  11. Steady motion of skyrmions and domains walls under diffusive spin torques

    KAUST Repository

    Elías, Ricardo Gabriel

    2017-03-09

    We explore the role of the spin diffusion of conducting electrons in two-dimensional magnetic textures (domain walls and skyrmions) with spatial variation of the order of the spin precession length λex. The effect of diffusion reflects in four additional torques that are third order in spatial derivatives of magnetization and bilinear in λex and in the nonadiabatic parameter β′. In order to study the dynamics of the solitons when these diffusive torques are present, we derive the Thiele equation in the limit of steady motion and we compare the results with the nondiffusive limit. When considering a homogenous current these torques increase the longitudinal velocity of transverse domain walls of width Δ by a factor (λex/Δ)2(α/3), α being the magnetic damping constant. In the case of single skyrmions with core radius r0 these new contributions tend to increase the Magnus effect in an amount proportional to (λex/r0)2(1+2αβ′).

  12. Vagal control of cardiac electrical activity and wall motion during ventricular fibrillation in large animals.

    Science.gov (United States)

    Naggar, Isaac; Nakase, Ko; Lazar, Jason; Salciccioli, Louis; Selesnick, Ivan; Stewart, Mark

    2014-07-01

    Vagal inputs control pacemaking and conduction systems in the heart. Anatomical evidence suggests a direct ventricular action, but functional evidence that separates direct and indirect (via the conduction system) vagal actions is less well established. We studied vagus nerve stimulation (VNS) during sinus rhythm and ventricular fibrillation (VF) in pigs and sheep to determine: 1) the range of unilateral and bilateral actions (inotropic and chronotropic) and 2) whether VNS alters left ventricular motion and/or electrical activity during VF, a model of abnormal electrical conduction of the left ventricle that excludes sinus and atrioventricular nodal function. Adult pigs (N=8) and sheep (N=10) were anesthetized with urethane and mechanically ventilated. VNS was performed in animals at 1, 2, 5, 10, 20, 50, and 100Hz for 20s. VF was induced with direct current to the ventricles or occlusion of the left anterior descending coronary artery. In 4 pigs and 3 sheep, left ventricular wall motion was assessed from endocardial excursion in epicardial echocardiography. In sheep and pigs, the best frequency among those tested for VNS during sinus rhythm to produce sustained electrical and mechanical ventricular standstill was 50Hz for unilateral or bilateral stimulation. When applied during VF, bilateral VNS increased the variability of the dominant VF frequency, indicating a direct impact on the excitability of ventricular myocytes, and decreased endocardial excursion by more than 50% during VF. We conclude that the vagus nerve directly modulates left ventricular function independently from its effects on the conduction system.

  13. The Subjective Sensation of Synchrony: An Experimental Study

    KAUST Repository

    Llobera, Joan

    2016-02-12

    People performing actions together have a natural tendency to synchronize their behavior. Consistently, people doing a task together build internal representations not only of their actions and goals, but also of the other people performing the task. However, little is known about which are the behavioral mechanisms and the psychological factors affecting the subjective sensation of synchrony, or “connecting” with someone else. In this work, we sought to find which factors induce the subjective sensation of synchrony, combining motion capture data and psychological measures. Our results show that the subjective sensation of synchrony is affected by performance quality together with task category, and time. Psychological factors such as empathy and negative subjective affects also correlate with the subjective sensation of synchrony. However, when people estimate synchrony as seen from a third person perspective, their psychological factors do not affect the accuracy of the estimation. We suggest that to feel this sensation it is necessary to, first, have a good joint performance and, second, to assume the existence of an attention monitoring mechanism that reports that the attention of both participants (self and other) is focused on the task.

  14. Theory of domain wall motion mediated magnetoelectric effects in a multiferroic composite

    Science.gov (United States)

    Petrov, V. M.; Srinivasan, G.

    2014-10-01

    A model is discussed for magnetoelectric (ME) interactions originating from the motion of magnetic domain walls (DWs) in a multiferroic composite of orthoferrites RFeO3 (RFO) with magnetic stripe domains and a piezoelectric such as lead magnesium niobate-lead titanate (PMN-PT). The DWs in RFO can be set in motion with an ac magnetic field up to a critical speed of 20 km/s, the highest for any magnetic system, leading to the excitation of bulk and shear magnetoacoustic waves. Thus, the ME coupling will arise from flexural deformation associated with DW motion (rather than the Joule magnetostriction mediated coupling under a static or quasistatic condition). A c plane orthoferrite with a single Néel-type DW in the bc plane and an ac magnetic field H along the c axis is assumed. The deflection in the bilayer due to DW motion is obtained when the DW velocity is a linear function H and the resulting induced voltage across PMN-PT is estimated. It is shown that a combination of spatial and time harmonics of the bending deformation leads to (i) a linear ME coefficient defined by αE=E/H and (ii) a quadratic ME coefficient αEQ=E/H2. The model is applied to yttrium orthoferrites (YFO) and a PMN-PT bilayer since YFO has one of the highest DW mobility amongst the orthoferrites. The coefficient αE is dependent on the DW position, and it is maximum when the DW equilibrium position is at the center of the sample. In YFO/PMN-PT the estimated low-frequency αE ˜ 30 mV/cm Oe and resonance value is 1.5 V/(cm Oe). Since orthoferrites (and PMN-PT) are transparent in the visible region and have a large Faraday rotation, the DW dynamics and the ME coupling could be studied simultaneously. The theory discussed here is of interest for studies on ME coupling and for applications such as magnetically controlled electro-optic devices.

  15. Spatio-temporal characteristics of large scale motions in a turbulent boundary layer from direct wall shear stress measurement

    Science.gov (United States)

    Pabon, Rommel; Barnard, Casey; Ukeiley, Lawrence; Sheplak, Mark

    2016-11-01

    Particle image velocimetry (PIV) and fluctuating wall shear stress experiments were performed on a flat plate turbulent boundary layer (TBL) under zero pressure gradient conditions. The fluctuating wall shear stress was measured using a microelectromechanical 1mm × 1mm floating element capacitive shear stress sensor (CSSS) developed at the University of Florida. The experiments elucidated the imprint of the organized motions in a TBL on the wall shear stress through its direct measurement. Spatial autocorrelation of the streamwise velocity from the PIV snapshots revealed large scale motions that scale on the order of boundary layer thickness. However, the captured inclination angle was lower than that determined using the classic method by means of wall shear stress and hot-wire anemometry (HWA) temporal cross-correlations and a frozen field hypothesis using a convection velocity. The current study suggests the large size of these motions begins to degrade the applicability of the frozen field hypothesis for the time resolved HWA experiments. The simultaneous PIV and CSSS measurements are also used for spatial reconstruction of the velocity field during conditionally sampled intense wall shear stress events. This material is based upon work supported by the National Science Foundation Graduate Research Fellowship under Grant No. DGE-1315138.

  16. Enhancement of spin Hall effect induced torques for current-driven magnetic domain wall motion: Inner interface effect

    KAUST Repository

    Bang, Do

    2016-05-23

    We investigate the current-induced domain wall motion in perpendicular magnetized Tb/Co wires with structure inversion asymmetry and different layered structures. We find that the critical current density to drive domain wall motion strongly depends on the layered structure. The lowest critical current density ∼15MA/cm2 and the highest slope of domain wall velocity curve are obtained for the wire having thin Co sublayers and more inner Tb/Co interfaces, while the largest critical current density ∼26MA/cm2 required to drive domain walls is observed in the Tb-Co alloy magnetic wire. It is found that the Co/Tb interface contributes negligibly to Dzyaloshinskii-Moriya interaction, while the effective spin-orbit torque strongly depends on the number of Tb/Co inner interfaces (n). An enhancement of the antidamping torques by extrinsic spin Hall effect due to Tb rare-earth impurity-induced skew scattering is suggested to explain the high efficiency of current-induced domain wall motion.

  17. Validity of acoustic quantification colour kinesis for detection of left ventricular regional wall motion abnormalities: a transoesophageal echocardiographic study.

    Science.gov (United States)

    Hartmann, T; Kolev, N; Blaicher, A; Spiss, C; Zimpfer, M

    1997-10-01

    Transoesophageal echocardiography is a sensitive monitor for intraoperative myocardial ischaemia. Colour kinesis is a new technology for echocardiographic assessment of regional wall motion based on acoustic quantification. We have examined the feasibility and accuracy of quantitative segmental analysis of colour kinesis images to provide objective evaluation of systolic regional wall motion during the perioperative period using transoesophageal echocardiography (TOE). Two-dimensional echocardiograms were obtained in the transgastric short-axis and long-axis views in 60 patients with coronary artery disease undergoing noncardiac surgery. End-systolic colour overlays superimposed on the grey scale images were obtained with colour kinesis to colour encode left ventricular endocardial motion throughout systole. These colour-encoded images were divided into segments and compared with corresponding conventional two-dimensional images. Six hundred of a potential 720 left ventricular wall segments were of sufficient resolution for grading by experts; they diagnosed wall motion abnormalities in 61 of these segments by a conventional method. In comparing the conventional TOE method with colour kinesis, there were 60 true positives, 482 true negatives, 57 false positives and 1 false negative result. This yielded a sensitivity of 98%, specificity of 89%, positive predictive value of 51% and negative predictive value of 100%. Translational and rotational movement of the heart and papillary muscle interference were common problems accounting for false positive diagnoses. We conclude that colour kinesis provides a basis for objective and on-line evaluation of left ventricular regional wall motion which is a sensitive but non-specific method. It may be a useful aid for the less experienced because it can potentially direct the anaesthetist's attention towards specific segments.

  18. Domain wall motion and precursor dynamics in PbZrO3

    Science.gov (United States)

    Puchberger, S.; Soprunyuk, V.; Majchrowski, A.; Roleder, K.; Schranz, W.

    2016-12-01

    Single crystals of PbZrO3 have been studied by dynamic mechanical analysis measurements in the low-frequency range f =0.02 -50 Hz. The complex Young's modulus exhibits a quite rich behavior and depends strongly on the direction of the applied dynamic force. In pseudocubic [100] c direction, we found intrinsic elastic behavior as expected from the Landau theory; at the antiferroelectric transition Tc≈510 K, a downwards cusp anomaly in Y' accompanied by a peak in Y'' points to a quadratic/linear order parameter/strain coupling in the Landau free energy. Both anomalies are increasing with decreasing frequency showing that the measurements are performed in the limit ω τth>1 . Frequency scans around Tc show energy dissipation, which could result from interphase boundary motion and/or heat diffusion. Above Tc, we observe a pronounced precursor softening, quite similar as it was found in other perovskites, which can be perfectly fitted including isotropic order parameter fluctuations. The low-frequency elastic response in [110] c direction is different. Below Tc, we find in addition to the intrinsic anomaly a strong contribution from ferroelastic domains, which leads to an additional softening in Y'. With decreasing temperatures this superelastic softening gradually disappears, due to an increasing relaxation time τDW for domain wall motion, indicating glassy behavior of domain freezing in PbZrO3. In contrast to the [100] c direction, for forces along [110] c, we found a pronounced precursor hardening, starting at about 60 K above Tc. Since this anomaly is of dynamic nature, starting at the same temperature as the observed birefringence and piezoelectric anomalies [Ko et al. Phys. Rev. B 87, 184110 (2013), 10.1103/PhysRevB.87.184110], we conclude that it originates from slow dynamic polar clusters, which freeze at T*≈550 K>Tc .

  19. Ultrawideband through-wall radar for detecting the motion of people in real time

    Science.gov (United States)

    Nag, Soumya; Barnes, Mark A.; Payment, Tim; Holladay, Gary

    2002-07-01

    Law enforcement officers and search-and-rescue workers often face the difficult task of determining the locations of people inside a building or obscured by smoke and debris. To address this problem, Time Domain Corporation (TDC) has developed a real-time, hand-held radar to detect the motion of persons in range and azimuth through non-metallic walls. This radar is a time modulated ultra-wide band (TM-UWB) impulse radar that generates a two-dimensional (2D) representation of moving targets in real time. The intentional transmit power emitted from the radar is comparable to the FCC Part 15, Class B limits. It has the following benefits: (1) covertness because of its ultra-low power noise-like signal, (2) high resolution at low radio frequencies for penetrating building materials, (3) reduced range ambiguities and clutter fold-over because of pseudo-random time modulation, and (4) clutter rejection because of the ultra-wide bandwidth of the signal. In this paper, an outline of the key parameters of the TDC prototype radar RadarVision2000 (RV2000) and a brief description of the algorithm that generates a motion map showing the range and direction of the moving people are presented. Some typical radar images of multiple targets for a variety of building materials and cluttered environment obtained using the prototype are shown. Finally, the paper presents some preliminary results for resolving the targets in the elevation plane along with a processing technique for reducing the intensity of multi-path responses in the images.

  20. Structure, stability, and motion of dislocations in double-wall carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    Zhang Kai-Wang; Li Zhong-Qiu; Wu Jian; Peng Xiang-Yang; Tan Xin-Jun; Sun Li-Zhong; Zhong Jian-Xin

    2012-01-01

    In this paper,a novel double-wall carbon nanotube (DWCNT) with both edge and screw dislocations is studied by using the molecular dynamics (MD) method. The differences between two adjacent tubule indexes of armchair and zigzag nanotubes are determined to be 5 and 9,respectively,by taking into account the symmetry,integrality,and thermal stability of the composite structures. It is found that melting first occurs near the dislocations,and the melting temperatures of the dislocated armchair and zigzag DWCNTs are around 2600 K-2700 K.At the premelting temperatures,the shrink of the dislocation loop,which is comprised of edge and screw dislocations,implies that the composite dislocation in DWCNTs has self-healing ability.The dislocated DWCNTs first fracture at the edge dislocations,which induces the entire break in axial tensile test. The dislocated DWCNTs have a smaller fracture strength compared to the perfect DWCNTs.Our results not only match with the dislocation glide of carbon nanotubes (CNTs) in experiments,but also can free from the electron beam radiation under experimental conditions observed by the high resolution transmission electron microscope (HRTEM),which is deemed to cause the motion of dislocation loop.

  1. Structure, stability, and motion of dislocations in double-wall carbon nanotubes

    Science.gov (United States)

    Zhang, Kai-Wang; Li, Zhong-Qiu; Wu, Jian; Peng, Xiang-Yang; Tan, Xin-Jun; Sun, Li-Zhong; Zhong, Jian-Xin

    2012-10-01

    In this paper, a novel double-wall carbon nanotube (DWCNT) with both edge and screw dislocations is studied by using the molecular dynamics (MD) method. The differences between two adjacent tubule indexes of armchair and zigzag nanotubes are determined to be 5 and 9, respectively, by taking into account the symmetry, integrality, and thermal stability of the composite structures. It is found that melting first occurs near the dislocations, and the melting temperatures of the dislocated armchair and zigzag DWCNTs are around 2600 K—2700 K. At the pre-melting temperatures, the shrink of the dislocation loop, which is comprised of edge and screw dislocations, implies that the composite dislocation in DWCNTs has self-healing ability. The dislocated DWCNTs first fracture at the edge dislocations, which induces the entire break in axial tensile test. The dislocated DWCNTs have a smaller fracture strength compared to the perfect DWCNTs. Our results not only match with the dislocation glide of carbon nanotubes (CNTs) in experiments, but also can free from the electron beam radiation under experimental conditions observed by the high resolution transmission electron microscope (HRTEM), which is deemed to cause the motion of dislocation loop.

  2. Feasibility and Reproducibility of Two-Dimensional Wall Motion Tracking (WMT) in Fetal Echocardiography

    Science.gov (United States)

    Enzensberger, Christian; Achterberg, Friederike; Degenhardt, Jan; Wolter, Aline; Graupner, Oliver; Herrmann, Johannes; Axt-Fliedner, Roland

    2017-01-01

    Objective The primary objective of this study was to determine the feasibility and reproducibility of 2-dimensional speckle tracking imaging based on the wall motion tracking (WMT) technique in fetal echocardiography. The secondary objective was to compare left and right ventricular global and segmental longitudinal peak strain values. Methods A prospective cross-sectional study was performed. Global and segmental longitudinal peak strain values of the left ventricle (LV) and right ventricle (RV) were assessed prospectively. Based on apical 4-chamber views, cine loops were acquired and digitally stored. Strain analysis was performed offline. Intra- and interobserver variabilities were analyzed. Results A total of 29 healthy fetuses with an echocardiogram performed between 19 and 37 weeks of gestation were included. Analysis was performed with a temporal resolution of 60 frames per second (fps). For both examiners, in all cases Cronbach’s alpha was>0.7. The interobserver variability showed a strong agreement in 50% of the segments (ICC 0.71–0.90). The global strain values for LV and RV were −16.34 and −14.65%, respectively. Segmental strain analysis revealed a basis to apex gradient with the lowest strain values in basal segments and the highest strain values in apical segments. Conclusion The assessment of fetal myocardial deformation parameters by 2D WMT is technically feasible with good reproducibility. PMID:28210715

  3. Classification of LV wall motion in cardiac MRI using kernel Dictionary Learning with a parametric approach.

    Science.gov (United States)

    Mantilla, Juan; Paredes, Jose; Bellanger, Jean-J; Donal, Erwan; Leclercq, Christophe; Medina, Ruben; Garreau, Mireille

    2015-01-01

    In this paper, we propose a parametric approach for the assessment of wall motion in Left Ventricle (LV) function in cardiac cine-Magnetic Resonance Imaging (MRI). Time-signal intensity curves (TSICs) are identified in Spatio-temporal image profiles extracted from different anatomical segments in a cardiac MRI sequence. Different parameters are constructed from specific TSICs that present a decreasing then increasing shape reflecting dynamic information of the LV contraction. The parameters extracted from these curves are related to: 1) an average curve based on a clustering process, 2) curve skewness and 3) cross correlation values between each average clustered curve and a patient-specific reference. Several tests are performed in order to construct different vectors to train a sparse classifier based on kernel Dictionary Learning (DL). Results are compared with other classifiers like Support Vector Machine (SVM) and Discriminative Dictionary Learning. The best classification performance is obtained with information of skewness and the average curve with an accuracy about 94% using the mentioned sparse based kernel DL with a radial basis function kernel.

  4. Short-term effect of volume recruitment-derecruitment manoeuvre on chest-wall motion in Duchenne muscular dystrophy.

    Science.gov (United States)

    Meric, Henri; Falaize, Line; Pradon, Didier; Lacombe, Matthieu; Petitjean, Michel; Orlikowski, David; Prigent, Hélène; Lofaso, Frédéric

    2017-05-01

    Because progressive respiratory muscle weakness leads to decreased chest-wall motion with eventual ribcage stiffening, the purpose was to compare vital capacity (VC) and contributions of chest-wall compartments before and after volume recruitment-derecruitment manoeuvres (VRDM) in Duchenne muscular dystrophy (DMD). We studied nine patients with DMD and VC lower than 30% of predicted. VRDM was performed using 15 insufflations-exsufflations of +30 to -30 cmH2O. VC and three-dimensional chest-wall motion were measured, as well as oxygen saturation, transcutaneous partial pressure of carbon dioxide and the rapid shallow breathing index (respiratory rate/tidal volume) before (baseline) and immediately and 1 hour after VRDM. VC increased significantly immediately after VRDM (108% ± 7% of baseline, p = 0.018) but returned to baseline within 1 hour, and the rapid shallow breathing index increased significantly. The non-dominant side systematically increased immediately after VRDM ( p = 0.0077), and in the six patients with abnormal breathing asymmetry (difference >10% of VC) at baseline, this asymmetry was corrected immediately and/or 1 hour after VRDM. VRDM improved VC and reduced chest-wall motion asymmetry, but this beneficial effect waned rapidly with respiratory muscle fatigue, suggesting that VRDM may need to be repeated during the day to produce lasting benefits.

  5. A cellular scale numerical study of the effect of mechanical properties of erythrocytes on the near-wall motion of platelets

    Science.gov (United States)

    Xu, Jing; Wang, Xiao-Long; Liu, Yun-Qiao; Gong, Xiao-Bo

    2014-04-01

    The effect of mechanical properties of erythrocytes on the near-wall motion of platelets was numerically studied with the immersed boundary method. Cells were modeled as viscous-fluid-filled capsules surrounded by hyper-elastic membranes with negligible thickness. The numerical results show that with the increase of hematocrit, the near-wall approaching of platelets is enhanced, with which platelets exhibit larger deformation and orientation angle of its near-wall tank-treading motion, and the lateral force pushing platelets to the wall is increased with larger fluctuation amplitude. Meanwhile the near-wall approaching is reduced by increasing the stiffness of erythrocytes. [Figure not available: see fulltext.

  6. Endogenous rhythms influence interpersonal synchrony.

    Science.gov (United States)

    Zamm, Anna; Wellman, Chelsea; Palmer, Caroline

    2016-05-01

    Interpersonal synchrony, the temporal coordination of actions between individuals, is fundamental to social behaviors from conversational speech to dance and music-making. Animal models indicate constraints on synchrony that arise from endogenous rhythms: Intrinsic periodic behaviors or processes that continue in the absence of change in external stimulus conditions. We report evidence for a direct causal link between endogenous rhythms and interpersonal synchrony in a music performance task, which places high demands on temporal coordination. We first establish that endogenous rhythms, measured by spontaneous rates of individual performance, are stable within individuals across stimulus materials, limb movements, and time points. We then test a causal link between endogenous rhythms and interpersonal synchrony by pairing each musician with a partner who is either matched or mismatched in spontaneous rate and by measuring their joint behavior up to 1 year later. Partners performed melodies together, using either the same or different hands. Partners who were matched for spontaneous rate showed greater interpersonal synchrony in joint performance than mismatched partners, regardless of hand used. Endogenous rhythms offer potential to predict optimal group membership in joint behaviors that require temporal coordination.

  7. Current-induced domain wall motion in Co/Ni nano-wires with different Co and Ni thicknesses

    Energy Technology Data Exchange (ETDEWEB)

    Ueda, K; Chiba, D; Koyama, T; Yamada, G; Ono, T [Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto, 611-0011 (Japan); Tanigawa, H; Fukami, S; Suzuki, T; Ohshima, N; Ishiwata, N [NEC Corporation, 1120 Shimokuzawa, Chuo-ku, Sagamihara, Kanagawa 252-5298 (Japan); Nakatani, Y, E-mail: ono@scl.kyoto-u.ac.jp [University of Electro-communications, Chofu, Tokyo, 182-8585 (Japan)

    2011-01-01

    The authors have investigated magnetic domain wall motion induced by electric currents in ferromagnetic nano-wires made of Co/Ni multilayers. The thicknesses of Co and Ni layers were changed, whereas the numbers of layer stacks of Co and Ni were the same in all samples. The sample with thinner total Co/Ni thickness showed the lower threshold current density for the domain wall motion as an overall trend, which is qualitatively in agreement with the expectation by the theory based on the adiabatic spin-transfer model. The lowest threshold current density was 2.9x10{sup 11} A/m{sup 2} obtained in the sample with the total Co/Ni thickness of 3.4 nm and the wire width of 110 nm.

  8. On-line assessment of regional ventricular wall motion by transesophageal echocardiography with color kinesis during minimally invasive coronary artery bypass grafting.

    Science.gov (United States)

    Kotoh, K; Watanabe, G; Ueyama, K; Uozaki, M; Suzuki, M; Misaki, T; Wakasugi, M; Ito, Y

    1999-05-01

    Our objective was to determine the changes in regional ventricular wall motion during minimally invasive direct coronary artery bypass grafting by color kinesis using transesophageal echocardiography. Minimally invasive coronary artery bypass grafting was performed in 34 patients, during which transesophageal echocardiography was used. Thirteen patients had isolated disease of the left anterior descending artery. Regional ventricular wall motion was analyzed by color kinesis with the SONOS 2500 transesophageal echocardiograph (Hewlett-Packard Co, Andover, Mass). On-line assessment of regional wall motion was continued during the operation. Wall motion abnormalities during ischemia were present in 4 cases, left ventricular mid-anterior hypokinesis in 3 cases, and left ventricular apical-lateral hypokinesis in 1 case. In all cases, wall motion was maintained after bypass. In patients with total coronary occlusion, changes in wall motion did not occur during anastomosis. Color kinesis allowed us to evaluate the change in regional ventricular wall motion induced by myocardial ischemia during minimally invasive coronary artery bypass grafting both objectively and quantitatively.

  9. SVM-based classification of LV wall motion in cardiac MRI with the assessment of STE

    Science.gov (United States)

    Mantilla, Juan; Garreau, Mireille; Bellanger, Jean-Jacques; Paredes, José Luis

    2015-01-01

    In this paper, we propose an automated method to classify normal/abnormal wall motion in Left Ventricle (LV) function in cardiac cine-Magnetic Resonance Imaging (MRI), taking as reference, strain information obtained from 2D Speckle Tracking Echocardiography (STE). Without the need of pre-processing and by exploiting all the images acquired during a cardiac cycle, spatio-temporal profiles are extracted from a subset of radial lines from the ventricle centroid to points outside the epicardial border. Classical Support Vector Machines (SVM) are used to classify features extracted from gray levels of the spatio-temporal profile as well as their representations in the Wavelet domain under the assumption that the data may be sparse in that domain. Based on information obtained from radial strain curves in 2D-STE studies, we label all the spatio-temporal profiles that belong to a particular segment as normal if the peak systolic radial strain curve of this segment presents normal kinesis, or abnormal if the peak systolic radial strain curve presents hypokinesis or akinesis. For this study, short-axis cine- MR images are collected from 9 patients with cardiac dyssynchrony for which we have the radial strain tracings at the mid-papilary muscle obtained by 2D STE; and from one control group formed by 9 healthy subjects. The best classification performance is obtained with the gray level information of the spatio-temporal profiles using a RBF kernel with 91.88% of accuracy, 92.75% of sensitivity and 91.52% of specificity.

  10. Usefulness of coronary flow reserve over regional wall motion when added to dual-imaging dipyridamole echocardiography.

    Science.gov (United States)

    Rigo, Fausto; Richieri, Margherita; Pasanisi, Emilio; Cutaia, Valeria; Zanella, Carlo; Della Valentina, Patrizia; Di Pede, Francesco; Raviele, Antonio; Picano, Eugenio

    2003-02-01

    Vasodilator stress echocardiography allows semi-simultaneous imaging of left anterior descending (LAD) coronary flow and regional wall function. To assess the relative (and additive?) value of regional flow and function for noninvasive identification of angiographically assessed LAD disease in patients with chest pain syndrome, we studied 230 consecutive in-hospital patients (134 men, aged 63.5 +/- 11 years) with chest pain syndrome and normal regional and global left ventricular function. All patients underwent stress echocardiography with dipyridamole (up to 0.84 mg/kg over 10 minutes), including wall motion analysis by 2-dimensional echocardiography and coronary flow reserve (CFR) evaluation of the LAD artery by Doppler, with or without contrast injection. A new regional wall motion abnormality in >or=2 contiguous segments was required for 2-dimensional echocardiographic positivity. CFR was evaluated as the ratio of dipyridamole to peak diastolic coronary blood flow velocity at rest. All patients underwent coronary angiography within 60 days; a quantitatively assessed diameter reduction >50% of the LAD artery was considered significant. Of the 230 patients, 70 had LAD disease. A regional wall motion abnormality in LAD territory was present in 52 patients, and reduced CFR (<1.9) in 62 patients. Sensitivity for detecting LAD disease was 74% for 2-dimensional echocardiography (95% confidence interval [CI] 64% to 84%) and 81% for CFR <1.9 (95% CI 72% to 90%); specificity was 91% (95% CI 87% to 96%) for 2-dimensional echocardiography and 84% for CFR (95% CI 79% to 90%). Accuracy was 86% for 2-dimensional echocardiography (95% CI 82% to 91%) and 83.5% for CFR (95% CI 79% to 88%). When 2-dimensional echocardiography and CFR criteria were considered, sensitivity increased to 93% (95% CI 87% to 99%), with 80.6% specificity (95% CI 74.5% to 86.7%). CFR was assessed during vasodilator stress echocardiography. Its diagnostic accuracy for detecting LAD disease was comparable

  11. Injection and controlled motion of conducting domain walls in improper ferroelectric Cu-Cl boracite

    Science.gov (United States)

    McQuaid, Raymond G. P.; Campbell, Michael P.; Whatmore, Roger W.; Kumar, Amit; Gregg, J. Marty

    2017-05-01

    Ferroelectric domain walls constitute a completely new class of sheet-like functional material. Moreover, since domain walls are generally writable, erasable and mobile, they could be useful in functionally agile devices: for example, creating and moving conducting walls could make or break electrical connections in new forms of reconfigurable nanocircuitry. However, significant challenges exist: site-specific injection and annihilation of planar walls, which show robust conductivity, has not been easy to achieve. Here, we report the observation, mechanical writing and controlled movement of charged conducting domain walls in the improper-ferroelectric Cu3B7O13Cl. Walls are straight, tens of microns long and exist as a consequence of elastic compatibility conditions between specific domain pairs. We show that site-specific injection of conducting walls of up to hundreds of microns in length can be achieved through locally applied point-stress and, once created, that they can be moved and repositioned using applied electric fields.

  12. Temperature estimation in a ferromagnetic Fe-Ni nanowire involving a current-driven domain wall motion.

    Science.gov (United States)

    Yamaguchi, A; Hirohata, A; Ono, T; Miyajima, H

    2012-01-18

    We observed a magnetic domain wall (DW) motion induced by the spin-polarized pulsed current in a nanoscale Fe(19)Ni(81) wire using a magnetic force microscope. High current density, which is of the order of 10(11) A m(-2), was required for the DW motion. A simple method to estimate the temperature of the wire was developed by comparing the wire resistance measured during the DW motion with the temperature dependence of the wire resistance. Using this method, we found the temperature of the wire was proportional to the square of the current density and became just beneath at the threshold Curie temperature. Our experimental data qualitatively support this analytical model that the temperature is proportional to the resistivity, thickness, width of the wire and the square of the current density, and also inversely proportional to the thermal conductivity.

  13. Nonverbal synchrony of head- and body-movement in psychotherapy: different signals have different associations with outcome

    Directory of Open Access Journals (Sweden)

    Fabian eRamseyer

    2014-09-01

    Full Text Available Objective: The coordination of patient’s and therapist’s bodily movement – nonverbal synchrony – has been empirically shown to be associated with psychotherapy outcome. This finding was based on dynamic movement patterns of the whole body. The present paper is a new analysis of an existing dataset (Ramseyer & Tschacher, 2011, which extends previous findings by differentiating movements pertaining to head and upper-body regions. Method: In a sample of 70 patients (37 female, 33 male treated at an outpatient psychotherapy clinic, we quantified nonverbal synchrony with an automated objective video-analysis algorithm (Motion Energy Analysis, MEA. Head- and body-synchrony was quantified during the initial 15 minutes of video-recorded therapy sessions. Micro-outcome was assessed with self-report post-session questionnaires provided by patients and their therapists. Macro-outcome was measured with questionnaires that quantified attainment of treatment goals and changes in experiencing and behavior at the end of therapy. Results: The differentiation of head- and body-synchrony showed that these two facets of motor coordination were differentially associated with outcome. Head-synchrony predicted global outcome of therapy, while body-synchrony did not, and body-synchrony predicted session outcome, while head-synchrony did not. Conclusions: The results pose an important amendment to previous findings, which showed that nonverbal synchrony embodied both outcome and interpersonal variables of psychotherapy dyads. The separation of head- and body-synchrony suggested that distinct mechanisms may operate in these two regions: Head-synchrony embodied phenomena with a long temporal extension (overall therapy success, while body-synchrony embodied phenomena of a more immediate nature (session-level success. More explorations with fine-grained analyses of synchronized phenomena in nonverbal behavior may shed additional light on the embodiment of

  14. Identification and Assessment of Paradoxical Ventricular Wall Motion Using ECG Gated Blood Pool Scan - Comparison of cine Loop , Phase Analysis and Paradox Image -

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae Tae; Kim, Gwang Weon; Lee, Kyu Bo; Chung, Byung Chun; Whang, Kee Suk; Chae, Sung Chul; Paek, Wee Hyun; Cheon, Jae Eun [Kyungpook National University School of Medicine, Daegu (Korea, Republic of); Lee, Hyong Woo; Chung, Jin Hong [Yeongnam National University College of Medicine, Daegu (Korea, Republic of)

    1990-07-15

    Sixty-four patients with paradoxical ventricular wall motion noticed both in angiocardiography or 2-dimensional echocardiography were assessed by ECG gated blood pool scan (GBPS). Endless cine loop image, phase and amplitude images and paradox image obtained by visual inspection of each cardiac beat or Fourier transformation of acquired raw data were investigated to determine the incremental value of GBPS with these processing methods for identification of paradoxical ventricular wall motion. The results were as follows:1) Paradoxical wall motions were observed on interventricular septum in 34 cases, left ventricular free wall in 26 and right ventricular wall in 24. Underlying heart diseases were is chemic (23 cases) valvular(9), congenital heart disease (12), cardiomyopathy (5), pericardial effusion(5), post cardiac surgery(3), corpulmonale (2), endocarditis (l) and right ventricular tumor(l). 2) Left ventricular ejection fractions of patients with paradoxical left ventricular wall motion were significantly lower than those with paradoxical septal motion (p <0.005). 3) The sensitivity of each processing methods for detecting paradoxical wall motion was 76.9% by phase analysis, 74.6% by endless cine loop mapping and 68.4% by paradox image manipulation respectively. Paradoxial motions visualized only in phase, paradox or both images were appeared as hypokinesia or akinesia in cine loop image. 4) All events could be identified by at least one of above three processing methods, however only 34 cases (48.4%) showed the paradoxical motions in all of the three images. By these findings, we concluded that simultaneous inspection of all above three processing methods-endless cine loop, phase analysis and paradox image is necessary for accurate identification and assessment of paradoxical ventricular wall motion when performing GBPS.

  15. Clinical Study of the Ascending Aorta Wall Motion by Velocity Vector Imaging in Patients with Primary Hypertension

    Institute of Scientific and Technical Information of China (English)

    Lei WANG; Jing WANG; Mingxing XIE; Xinfang WANG; Qing LV; Ming CHEN; Shaoping ZHENG

    2009-01-01

    We studied the wall motion characteristics of the ascending aorta by velocity vector im-aging (VVI) in primary hypertension patients.The ascending aortas both in 30 patients with primary hypertension and 30 normal controls were examined by Acuson sequoia 512 equiped with VVI.The maximum velocity (Vs,Ve) of every point on the anterior wall of ascending aorta both in systole and diastole was measured.The aortic diameter was wider in the hypertension patients than that in the healthy subjects (P0.05).The velocity curves of the anterior wall of ascending aorta both in the hypertension and healthy subjects were regular,and the curve in systole was named S wave and that in diastole named E wave.The velocity of S wave and E wave was slower in the hypertension pa-tients than that in the healthy subjects (P<0.05).The time to peak of S wave on the anterior wall of ascending aorta in systole was shorter in the hypertension patients than in the healthy subjects (P<0.05).VVI could be used to accurately and directly observe the movement character of the as-cending aorta walls,which would help us understand the elasticity of great arteries in patients with hypertension.

  16. Motion

    CERN Document Server

    Graybill, George

    2007-01-01

    Take the mystery out of motion. Our resource gives you everything you need to teach young scientists about motion. Students will learn about linear, accelerating, rotating and oscillating motion, and how these relate to everyday life - and even the solar system. Measuring and graphing motion is easy, and the concepts of speed, velocity and acceleration are clearly explained. Reading passages, comprehension questions, color mini posters and lots of hands-on activities all help teach and reinforce key concepts. Vocabulary and language are simplified in our resource to make them accessible to str

  17. Carotid artery longitudinal wall motion is associated with local blood velocity and left ventricular rotational, but not longitudinal, mechanics.

    Science.gov (United States)

    Au, Jason S; Ditor, David S; MacDonald, Maureen J; Stöhr, Eric J

    2016-07-01

    Recent studies have identified a predictable movement pattern of the common carotid artery wall in the longitudinal direction. While there is evidence that the magnitude of this carotid artery longitudinal wall motion (CALM) is sensitive to cardiovascular health status, little is known about the determinants of CALM The purpose of this integrative study was to evaluate the contribution of left ventricular (LV) cardiac motion and local blood velocity to CALM Simultaneous ultrasound measurements of CALM, common carotid artery mean blood velocity (MBV), and left ventricular motion were performed in ten young, healthy individuals (6 males; 22 ± 1 years). Peak anterograde CALM occurred at a similar time as peak MBV (18.57 ± 3.98% vs. 18.53 ± 2.81% cardiac cycle; t-test: P = 0.94; ICC: 0.79, P longitudinal displacement was not associated with peak CALM (r = 0.11, P = 0.77). These results suggest that the rotational mechanical movement of the LV base may be closely associated with longitudinal mechanics in the carotid artery. This finding may have important implications for interpreting the complex relationship between ventricular and vascular function.

  18. Lower limb pneumatic compression during dobutamine stress echocardiography in patients with normal resting wall motion: will it increase diagnostic accuracy?

    Science.gov (United States)

    Abdel-Salam, Zainab; Allam, Lawra; Wadie, Bassem; Enany, Bassem; Nammas, Wail

    2015-01-01

    Pneumatic compression of the lower part of the body increases systemic vascular resistance and left ventricular afterload. We compared the diagnostic accuracy of dobutamine stress echocardiography (DSE) with pneumatic compression of the lower extremities, vs. standard DSE, for detection of angiographically significant coronary artery disease (CAD) in patients with normal baseline resting wall motion. We enrolled 70 consecutive patients with no resting wall motion abnormalities (WMA), who underwent DSE. DSE was repeated with pneumatic compression of the lower extremities three days after the initial standard DSE. A positive test was defined as the induction of WMA in at least two contiguous non-overlap segments at any stage of dobutamine infusion. Significant coronary stenosis was defined as ≥ 50% obstruction of ≥ 1 sizable artery by coronary angiography. The mean age of the study cohort was 54.7 ± 9.9 years; 55.7% were females. Thirty-eight (54.3%) patients had significant CAD. The mean test duration was 15.8 ± 5.1 min for standard DSE and 11.7 ± 4.1 min for DSE with pneumatic compression. Analysis of standard DSE revealed sensitivity, specificity, and positive and negative predictive values of 81.6%, 90.6%, 91.2%, and 80.6%, respectively; overall accuracy was 85.7%. Analysis of DSE with pneumatic compression revealed sensitivity, specificity, and positive and negative predictive values of 89.5%, 87.5%, 89.5%, and 87.5%, respectively; overall accuracy was 88.6%. In symptomatic patients with suspected CAD referred for evaluation by DSE, who have no resting wall motion abnormalities, pneumatic compression of the lower extremities during DSE improved the sensitivity but slightly reduced the specificity for detection of angiographically significant CAD, compared with standard DSE. Moreover, it reduced the test duration.

  19. Interpretation of cardiac wall motion from cine-MRI combined with parametric imaging based on the Hilbert transform.

    Science.gov (United States)

    Benameur, Narjes; Caiani, Enrico Gianluca; Arous, Younes; Abdallah, Nejmeddine Ben; Kraiem, Tarek

    2017-08-01

    The aim of this study was to test and validate the clinical impact of parametric amplitude images obtained using the Hilbert transform on the regional interpretation of cardiac wall motion abnormalities from cine-MR images by non-expert radiologists compared with expert consensus. Cine-MRI short-axis images obtained in 20 patients (10 with myocardial infarction, 5 with myocarditis and 5 with normal function) were processed to compute a parametric amplitude image for each using the Hilbert transform. Two expert radiologists blindly reviewed the cine-MR images to define a gold standard for wall motion interpretation for each left ventricular sector. Two non-expert radiologists reviewed and graded the same images without and in combination with parametric images. Grades assigned to each segment in the two separate sessions were compared with the gold standard. According to expert interpretation, 264/320 (82.5%) segments were classified as normal and 56/320 (17.5%) were considered abnormal. The accuracy of the non-expert radiologists' grades compared to the gold standard was significantly improved by adding parametric images (from 87.2 to 94.6%) together with sensitivity (from 64.29 to 84.4%) and specificity (from 92 to 96.9%), also resulting in reduced interobserver variability (from 12.8 to 5.6%). The use of parametric amplitude images based on the Hilbert transform in conjunction with cine-MRI was shown to be a promising technique for improvement of the detection of left ventricular wall motion abnormalities in less expert radiologists.

  20. Synchrony-optimized power grids

    CERN Document Server

    Pinto, Rafael S

    2014-01-01

    We investigate synchronization in power grids, which we assume to be modeled by a network of Kuramoto oscillators with inertia. More specifically, we study the optimization of the power grid topology to favor the network synchronization. We introduce a rewiring algorithm which consists basically in a hill climb scheme where the edges of the network are swapped in order enhance the main measures of synchronization. As a byproduct of the optimization algorithm, we typically have also the anticipation of the synchronization onset for the optimized network. We perform several robustness tests for the synchrony-optimized power grids, including the impact of consumption peaks. In our analyses, we investigate synthetic random networks, which we consider as hypothetical decentralized power generation situations, and also a network based in the actual power grid of Spain, which corresponds to the current paradigm of centralized power grids. The synchrony-optimized power grids obtained by our algorithm have some intere...

  1. Clinical impact of ' in-treatment' wall motion abnormalities in hypertensive patients with left ventricular hypertrophy: the LIFE study

    DEFF Research Database (Denmark)

    Cicala, S.; Simone, G. de; Wachtell, K.;

    2008-01-01

    to analyze the primary composite endpoint of cardiovascular death, MI, or stroke and, separately, for fatal and nonfatal MI and hospitalized heart failure. Results During a mean follow-up of 4.8 years, an event was recorded in 67 ( 9%) patients. In Cox models after adjusting for age, gender, treatment, blood......, however, never been investigated. We examined whether 'in- treatment' wall motion abnormalities predicted outcome in the Losartan Intervention For Endpoint ( LIFE) reduction in hypertension echocardiographic substudy. Methods We studied 749 patients without coronary artery disease, myocardial infarction...

  2. Construction of a two-parameter empirical model of left ventricle wall motion using cardiac tagged magnetic resonance imaging data

    Directory of Open Access Journals (Sweden)

    Shi Jack J

    2012-10-01

    Full Text Available Abstract Background A one-parameter model was previously proposed to characterize the short axis motion of the LV wall at the mid-ventricle level. The single parameter of this model was associated with the radial contraction of myocardium, but more comprehensive model was needed to account for the rotation at the apex and base levels. The current study developed such model and demonstrated its merits and limitations with examples. Materials and methods The hearts of five healthy individuals were visualized using cardiac tagged magnetic resonance imaging (tMRI covering the contraction and relaxation phases. Based on the characteristics of the overall dynamics of the LV wall, its motion was represented by a combination of two components - radial and rotational. Each component was represented by a transformation matrix with a time-dependent variable α or β. Image preprocessing step and model fitting algorithm were described and applied to estimate the temporal profiles of α and β within a cardiac cycle at the apex, mid-ventricle and base levels. During this process, the tagged lines of the acquired images served as landmark reference for comparing against the model prediction of the motion. Qualitative and quantitative analyses were performed for testing the performance of the model and thus its validation. Results The α and β estimates exhibited similarities in values and temporal trends once they were scaled by the radius of the epicardium (repiand plotted against the time scaled by the period of the cardiac cycle (Tcardiac of each heart measured during the data acquisition. α/repi peaked at about Δt/Tcardiac=0.4 and with values 0.34, 0.4 and 0.3 for the apex, mid-ventricle and base level, respectively. β/repi similarly maximized in amplitude at about Δt/Tcardiac=0.4, but read 0.2 for the apex and - 0.08 for the base level. The difference indicated that the apex twisted more than the base. Conclusion It is feasible to empirically model

  3. The reliability of echocardiographic left ventricular wall motion index to identify high-risk patients for multicenter studies

    DEFF Research Database (Denmark)

    Gislason, Gunnar H; Gadsbøll, Niels; Quinones, Miguel A

    2006-01-01

    overall agreement for identifying patients with severe impairment of LV function. This not only underscores the value of LV-WMI as a useful tool for selecting high-risk patients to be included in multicenter studies but also serves to warn against the use of rigid cutoff values for WMI in the treatment......OBJECTIVE: To study whether the use of echocardiographic left ventricular (LV) wall motion index (WMI) is a dependable parameter for identifying patients with LV dysfunction to be enrolled in multicenter trials. METHODS: Videotaped echocardiographic examinations from 200 randomly selected patients...

  4. Collective coordinate models of domain wall motion in perpendicularly magnetized systems under the spin hall effect and longitudinal fields

    Science.gov (United States)

    Nasseri, S. Ali; Moretti, Simone; Martinez, Eduardo; Serpico, Claudio; Durin, Gianfranco

    2017-03-01

    Recent studies on heterostructures of ultrathin ferromagnets sandwiched between a heavy metal layer and an oxide have highlighted the importance of spin-orbit coupling (SOC) and broken inversion symmetry in domain wall (DW) motion. Specifically, chiral DWs are stabilized in these systems due to the Dzyaloshinskii-Moriya interaction (DMI). SOC can also lead to enhanced current induced DW motion, with the Spin Hall effect (SHE) suggested as the dominant mechanism for this observation. The efficiency of SHE driven DW motion depends on the internal magnetic structure of the DW, which could be controlled using externally applied longitudinal in-plane fields. In this work, micromagnetic simulations and collective coordinate models are used to study current-driven DW motion under longitudinal in-plane fields in perpendicularly magnetized samples with strong DMI. Several extended collective coordinate models are developed to reproduce the micromagnetic results. While these extended models show improvements over traditional models of this kind, there are still discrepancies between them and micromagnetic simulations which require further work.

  5. Quantification of the relative contribution of the different right ventricular wall motion components to right ventricular ejection fraction: the ReVISION method.

    Science.gov (United States)

    Lakatos, Bálint; Tősér, Zoltán; Tokodi, Márton; Doronina, Alexandra; Kosztin, Annamária; Muraru, Denisa; Badano, Luigi P; Kovács, Attila; Merkely, Béla

    2017-03-27

    Three major mechanisms contribute to right ventricular (RV) pump function: (i) shortening of the longitudinal axis with traction of the tricuspid annulus towards the apex; (ii) inward movement of the RV free wall; (iii) bulging of the interventricular septum into the RV and stretching the free wall over the septum. The relative contribution of the aforementioned mechanisms to RV pump function may change in different pathological conditions.Our aim was to develop a custom method to separately assess the extent of longitudinal, radial and anteroposterior displacement of the RV walls and to quantify their relative contribution to global RV ejection fraction using 3D data sets obtained by echocardiography.Accordingly, we decomposed the movement of the exported RV beutel wall in a vertex based manner. The volumes of the beutels accounting for the RV wall motion in only one direction (either longitudinal, radial, or anteroposterior) were calculated at each time frame using the signed tetrahedron method. Then, the relative contribution of the RV wall motion along the three different directions to global RV ejection fraction was calculated either as the ratio of the given direction's ejection fraction to global ejection fraction and as the frame-by-frame RV volume change (∆V/∆t) along the three motion directions.The ReVISION (Right VentrIcular Separate wall motIon quantificatiON) method may contribute to a better understanding of the pathophysiology of RV mechanical adaptations to different loading conditions and diseases.

  6. Magnet Fall inside a Conductive Pipe: Motion and the Role of the Pipe Wall Thickness

    Science.gov (United States)

    Donoso, G.; Ladera, C. L.; Martin, P.

    2009-01-01

    Theoretical models and experimental results are presented for the retarded fall of a strong magnet inside a vertical conductive non-magnetic tube. Predictions and experimental results are in good agreement modelling the magnet as a simple magnetic dipole. The effect of varying the pipe wall thickness on the retarding magnetic drag is studied for…

  7. Assessment of myocardial segmental function with coronary artery stenosis in multi-vessel coronary disease patients with normal wall motion.

    Science.gov (United States)

    Xie, M-Y; Lv, Q; Wang, J; Yin, J-B

    2016-04-01

    To discover the impact of the various degrees of coronary artery stenosis (CAD) on the left ventricular systolic dysfunction in steady state with quantitative analysis of the regional systolic myocardium in longitudinal, radial and circumferential direction in patients with coronary artery disease by two-dimensional speckle tracking imaging (STI). Forty-three normal wall motion-multi vessel coronary artery disease (NWM-MVD) patients labeled as the experimental groups and forty-two subjects with little risk of CAD marked as the control group were enrolled in this study. The two-dimensional STI was obtained in the apical long axis and three levels of the short axis of the left ventricle. The left ventricular wall was divided into 18 segments. The affected myocardia were divided into three groups: group B (coronary stenosis degree ≤50%), group C (coronary stenosis degree 50%-99%)and group D (coronary stenosis degree ≥99%). Using the Q-analysis software, the longitudinal, radial and circumferential systolic strain (SL, SR, SC) and strain ratio (SrL, SrR, SrC) of the myocardium were analyzed. The bradycardia in the NWM-MVD group is greater than that in the control group (16/43 vs. 7/42, p coronary stenosis degree ≤50%), group C (coronary stenosis degree 50%-99%)and group D (coronary stenosis degree ≥99%), especially the longitudinal and radial systolic function, even though they had normal wall motion. The SrL equaled 1.085 for the cut-off value, and the sums (1.348) of sensitivity (0.673) and specificity (0.675) were the greatest. Bradycardia might be a compensatory mechanism in NWM-MVD patients.

  8. Speed limit in internal space of domain walls via all-order effective action of moduli motion

    Science.gov (United States)

    Eto, Minoru; Hashimoto, Koji

    2016-03-01

    We find that motion in internal moduli spaces of generic domain walls has an upper bound for its velocity. Our finding is based on our generic formula for all-order effective actions of internal moduli parameter of domain wall solitons. It is known that the Nambu-Goldstone mode Z associated with spontaneous breaking of translation symmetry obeys a Nambu-Goto effective Lagrangian √{1 -(∂0Z )2 } detecting the speed of light (|∂0Z |=1 ) in the target spacetime. Solitons can have internal moduli parameters as well, associated with a breaking of internal symmetries such as a phase rotation acting on a field. We obtain, for generic domain walls, an effective Lagrangian of the internal moduli ɛ to all orders in (∂ɛ ). The Lagrangian is given by a function of the Nambu-Goto Lagrangian: L =g (√{1 +(∂μɛ )2 }). This shows generically the existence of an upper bound on ∂0ɛ , i.e., a speed limit in the internal space. The speed limit exists even for solitons in some nonrelativistic field theories, where we find that ɛ is a type I Nambu-Goldstone mode that also obeys a nonlinear dispersion to reach the speed limit. This offers a possibility of detecting the speed limit in condensed matter experiments.

  9. Speed limit in internal space of domain walls via all-order effective action of moduli motion

    CERN Document Server

    Eto, Minoru

    2015-01-01

    We find that motion in internal moduli spaces of generic domain walls has an upper bound for its velocity. Our finding is based on our generic formula for all-order effective actions of internal moduli parameter of domain wall solitons. It is known that the Nambu-Goldstone mode $Z$ associated with spontaneous breaking of translation symmetry obeys a Nambu-Goto effective Lagrangian $\\sqrt{1 - (\\partial_0 Z)^2}$ detecting the speed of light ($|\\partial_0 Z|=1$) in the target spacetime. Solitons can have internal moduli parameters as well, associated with a breaking of internal symmetries such as a phase rotation acting on a field. We obtain, for generic domain walls, an effective Lagrangian of the internal moduli $\\epsilon$ to all order in $(\\partial \\epsilon)$. The Lagrangian is given by a function of the Nambu-Goto Lagrangian: $L = g(\\sqrt{1 + (\\partial_\\mu \\epsilon)^2})$. This shows generically the existence of an upper bound on $\\partial_0 \\epsilon$, i.e. a speed limit in the internal space. The speed limit...

  10. Linear modeling of turbulent skin-friction reduction due to spanwise wall motion

    Science.gov (United States)

    Duque-Daza, Carlos; Baig, Mirza; Lockerby, Duncan; Chernyshenko, Sergei; Davies, Christopher; University of Warwick Team; Imperial College Team; Cardiff University Team

    2012-11-01

    We present a study on the effect of streamwise-travelling waves of spanwise wall velocity on the growth of near-wall turbulent streaks using a linearized formulation of the Navier-Stokes equations. The changes in streak amplification due to the travelling waves induced by the wall velocity are compared to published results of direct numerical simulation (DNS) predictions of the turbulent skin-friction reduction over a range of parameters; a clear correlation between these two sets of results is observed. Additional linearized simulations but at a much higher Reynolds numbers, more relevant to aerospace applications, produce results that show no marked differences to those obtained at low Reynolds number. It is also observed that a close correlation exists between DNS data of drag reduction and a very simple characteristic of the ``generalized'' Stokes layer generated by the streamwise-travelling waves. Carlos.Duque-Daza@warwick.ac.uk - School of Engineering, University of Warwick, Coventry CV4 7AL, UK caduqued@unal.edu.co - Department of Mechanical and Mechatronics Engineering, Universidad Nacional de Colombia.

  11. Nanoparticle stochastic motion in the inertial regime and hydrodynamic interactions close to a cylindrical wall

    OpenAIRE

    Vitoshkin, Helena; Yu, Hsiu-Yu; Eckmann, David M.; Ayyaswamy, Portonovo S.; Radhakrishnan, Ravi

    2016-01-01

    We have carried out direct numerical simulations (DNS) of the fluctuating Navier-Stokes equation together with the particle equations governing the motion of a nanosized particle or nanoparticle (NP) in a cylindrical tube. The effects of the confining boundary, its curvature, particle size, and particle density variations have all been investigated. To reveal how the nature of the temporal correlations (hydrodynamic memory) in the inertial regime is altered by the full hydrodynamic interactio...

  12. The Transient MHD Flow Generated by a PeriodicWall Motion in a Porous Space

    Directory of Open Access Journals (Sweden)

    Mohammed Abdulhameed

    2016-01-01

    Full Text Available The problem of transient flow of incompressible third grade fluid on the two-dimensional magnetohydrodynamic (MHD flow in a porous space is analyzed. The flow is generated due to the motion of the plate in its plane with a periodic velocity. Under the flow assumptions, the governing nonlinear partial differential equation is transformed into steady-state and transient nonlinear equations. The reduced equation for the transient flow is solved analytically using symmetry approach while the nonlinear steady-state equation is solved using a modified version of He’s homotopy perturbation method. The effect of several operating parameters on the flow hydromagnetic is discussed. The results indicated that for the considered case, t = 1:5 is the moment after which the time-dependent transient motion of the fluid can be approximated with the steady-state motion, described by the steady-state solution. It is clear that, after this value of time t the time-dependent transient solution can be neglected.

  13. Measuring multiple spike train synchrony.

    Science.gov (United States)

    Kreuz, Thomas; Chicharro, Daniel; Andrzejak, Ralph G; Haas, Julie S; Abarbanel, Henry D I

    2009-10-15

    Measures of multiple spike train synchrony are essential in order to study issues such as spike timing reliability, network synchronization, and neuronal coding. These measures can broadly be divided in multivariate measures and averages over bivariate measures. One of the most recent bivariate approaches, the ISI-distance, employs the ratio of instantaneous interspike intervals (ISIs). In this study we propose two extensions of the ISI-distance, the straightforward averaged bivariate ISI-distance and the multivariate ISI-diversity based on the coefficient of variation. Like the original measure these extensions combine many properties desirable in applications to real data. In particular, they are parameter-free, time scale independent, and easy to visualize in a time-resolved manner, as we illustrate with in vitro recordings from a cortical neuron. Using a simulated network of Hindemarsh-Rose neurons as a controlled configuration we compare the performance of our methods in distinguishing different levels of multi-neuron spike train synchrony to the performance of six other previously published measures. We show and explain why the averaged bivariate measures perform better than the multivariate ones and why the multivariate ISI-diversity is the best performer among the multivariate methods. Finally, in a comparison against standard methods that rely on moving window estimates, we use single-unit monkey data to demonstrate the advantages of the instantaneous nature of our methods.

  14. The contribution of 180° domain wall motion to dielectric properties quantified from in situ X-ray diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Fancher, C.M.; Brewer, S.; Chung, C.C.; Röhrig, S.; Rojac, T.; Estevesa, G.; Deluca, M.; Bassiri-Gharb, N.; Jones, J.L. (Mat. Cent. Leoben); (NCSU); (Joseph Stefan Inst.); (GIT)

    2017-03-01

    The contribution of 180° domain wall motion to polarization and dielectric properties of ferroelectric materials has yet to be determined experimentally. In this paper, an approach for estimating the extent of (180°) domain reversal during application of electric fields is presented. We demonstrate this method by determining the contribution of domain reversal to polarization in soft lead zirconate titanate during application of strong electric fields. At the maximum applied field, domain reversal was determined to account for >80% of the measured macroscopic polarization. We also apply the method to quantify the contribution of domain reversal to the weak-field dielectric permittivity of BaTiO3. The results of this analysis determined that domain reversal accounts for up to ~70% of the macroscopic dielectric permittivity in BaTiO3. These results demonstrate the predominance of domain reversal to high and low-field dielectric response in ferroelectric polycrystalline materials.

  15. The unsteady flow of a third-grade fluid caused by the periodic motion of an infinite wall with transpiration

    Directory of Open Access Journals (Sweden)

    M. Abdulhameed

    2015-12-01

    Full Text Available In this work, the unidirectional flow of an incompressible electrically conducting third-grade fluid past a vertical transpiration wall through a porous medium with time-dependent periodic motion is presented. The nonlinear partial differential equations are transformed to ordinary differential equation by means of symmetry reductions. The reduced equation is then solved analytically for steady-state and time-dependent transient parts. The time series of the transient flow velocity for different pertinent parameters are examined through plots. During the course of computation, it was observed that the time-dependent transient and steady-state solutions agree very well at large value of time when the ratio is related to fluid parameters γ∗γ>1.

  16. Small-scale deflagration cylinder test with velocimetry wall-motion diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Hooks, Daniel E [Los Alamos National Laboratory; Hill, Larry G [Los Alamos National Laboratory; Pierce, Timothy H [Los Alamos National Laboratory

    2010-01-01

    Predicting the likelihood and effects of outcomes resultant from thermal initiation of explosives remains a significant challenge. For certain explosive formulations, the general outcome can be broadly predicted given knowledge of certain conditions. However, there remain unexplained violent events, and increased statistical understanding of outcomes as a function of many variables, or 'violence categorization,' is needed. Additionally, the development of an equation of state equivalent for deflagration would be very useful in predicting possible detailed event consequences using traditional hydrodynamic detonation moders. For violence categorization, it is desirable that testing be efficient, such that it is possible to statistically define outcomes reliant on the processes of initiation of deflagration, steady state deflagration, and deflagration to detonation transitions. If the test simultaneously acquires information to inform models of violent deflagration events, overall predictive capabilities for event likelihood and consequence might improve remarkably. In this paper we describe an economical scaled deflagration cylinder test. The cyclotetramethylene tetranitramine (HMX) based explosive formu1lation PBX 9501 was tested using different temperature profiles in a thick-walled copper cylindrical confiner. This test is a scaled version of a recently demonstrated deflagration cylinder test, and is similar to several other thermal explosion tests. The primary difference is the passive velocimetry diagnostic, which enables measurement of confinement vessel wall velocities at failure, regardless of the timing and location of ignition.

  17. Field-induced domain wall motion of amorphous [CoSiB/Pt]{sub N} multilayers with perpendicular anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Y. H.; Lee, K. J.; Jung, M. H., E-mail: mhjung@sogang.ac.kr [Department of Physics, Sogang University, Seoul 121-742 (Korea, Republic of); Yoon, J. B.; Cho, J. H.; You, C.-Y. [Department of Physics, Inha University, Incheon 402-751 (Korea, Republic of); Kim, T. W. [Department of Advanced Materials Engineering, Sejong University, Seoul 143-747 (Korea, Republic of)

    2014-05-14

    Amorphous CoSiB/Pt multilayer is a perpendicular magnetic anisotropy material to achieve high squareness, low coercivity, strong anisotropy, and smooth domain wall (DW) motion, because of the smoother interface compared with crystalline multilayers. For [CoSiB(6 Å)/Pt (14 Å)]{sub N} multilayers with N = 3, 6, and 9, we studied the field-induced DW dynamics. The effective anisotropy constant K{sub 1}{sup eff} is 1.5 × 10{sup 6} erg/cm{sup 3} for all the N values, and the linear increment of coercive field H{sub c} with N gives constant exchange coupling J. By analyzing the field dependence of DW images at room temperature, a clear creep motion with the exponent μ = 1/4 could be observed. Even though the pinning field H{sub dep} slightly increases with N, the pinning potential energy U{sub c} is constant (=35 k{sub B}T) for all the N values. These results imply that the amorphous [CoSiB/Pt]{sub N} multilayers are inherently homogeneous compared to crystalline multilayers. For N ≤ 6, the pinning site density ρ{sub pin} is less than 1000/μm{sup 2}, which is about 1 pinning site per the typical device junction size of 30 × 30 nm{sup 2}. Also, the exchange stiffness constant A{sub ex} is obtained to be 0.48 × 10{sup −6} erg/cm, and the domain wall width is expected to be smaller than 5.5 nm. These results may be applicable for spin-transfer-torque magnetic random access memory and DW logic device applications.

  18. Usefulness of color kinesis imaging for evaluation of regional right ventricular wall motion in patients with surgically repaired tetralogy of Fallot.

    Science.gov (United States)

    Hayabuchi, Y; Matsuoka, S; Kubo, M; Kuroda, Y

    1998-11-15

    We evaluated regional right ventricular wall motion during systole in patients with surgically repaired tetralogy of Fallot (TOF) using color kinesis imaging. Color kinesis images were obtained in a subcostal sagittal view from 19 patients with repaired TOF (TOF group), aged 3 to 5 years, and 20 age-matched normal subjects (control group). For regional wall motion analysis, the endocardial motion distance and the fractional area change (FAC) were calculated for 6 segments obtained from color kinesis images. The endocardial inward excursion distances and the FACs in the upper, middle, and lower posterior segments of the TOF group were significantly greater than those of the control group (p kinesis measurements was excellent (y = 1.14x - 1.30, r = 0.87 for the endocardial inward excursion, and y = 1.03x +/- 0.56, r = 0.91 for the FAC). In conclusion, color kinesis is a useful method for assessing regional right ventricular wall motion. Segmental analysis of color kinesis images provides accurate, automated, and quantitative diagnosis of regional right ventricular wall motion abnormalities in patients with surgically repaired TOF.

  19. Characteristic dynamic modes and domain-wall motion in magnetic nanotubes excited by resonant rotating magnetic fields

    Science.gov (United States)

    Yang, Jaehak; Kim, Junhoe; Kim, Bosung; Cho, Young-Jun; Lee, Jae-Hyeok; Kim, Sang-Koog

    2016-07-01

    We performed micromagnetic numerical calculations to explore a cylindrical nanotube's magnetization dynamics and domain-wall (DW) motions driven by eigen-circular-rotating magnetic fields of different frequencies. We discovered the presence of two different localized DW oscillations as well as asymmetric ferromagnetic resonance precession and azimuthal spin-wave modes at the corresponding resonant frequencies of the circular-rotating fields. Associated with these intrinsic modes, there exist very contrasting DW motions of different speed and propagation direction for a given DW chirality. The direction and speed of the DW propagation were found to be controllable according to the rotation sense and frequency of noncontact circular-rotating fields. Furthermore, spin-wave emissions from the moving DW were observed at a specific field frequency along with their Doppler effect. This work furthers the fundamental understanding of soft magnetic nanotubes' intrinsic dynamic modes and spin-wave emissions and offers an efficient means of manipulating the speed and direction of their DW propagations.

  20. Analysis of Peristaltic Motion of a Nanofluid with Wall Shear Stress, Microrotation, and Thermal Radiation Effects

    Directory of Open Access Journals (Sweden)

    C. Dhanapal

    2016-01-01

    Full Text Available This paper analyzes the peristaltic flow of an incompressible micropolar nanofluid in a tapered asymmetric channel in the presence of thermal radiation and heat sources parameters. The rotation of the nanoparticles is incorporated in the flow model. The equations governing the nanofluid flow are modeled and exact solutions are managed under long wavelength and flow Reynolds number and long wavelength approximations. Explicit expressions of axial velocity, stream function, microrotation, nanoparticle temperature, and concentration have been derived. The phenomena of shear stress and trapping have also been discussed. Finally, the influences of various parameters of interest on flow variables have been discussed numerically and explained graphically. Besides, the results obtained in this paper will be helpful to those who are working on the development of various realms like fluid mechanics, the rotation, Brownian motion, thermophoresis, coupling number, micropolar parameter, and the nondimensional geometry parameters.

  1. Analysis of Peristaltic Motion of a Nanofluid with Wall Shear Stress, Microrotation, and Thermal Radiation Effects

    Science.gov (United States)

    Dhanapal, C.; Kamalakkannan, J.; Prakash, J.

    2016-01-01

    This paper analyzes the peristaltic flow of an incompressible micropolar nanofluid in a tapered asymmetric channel in the presence of thermal radiation and heat sources parameters. The rotation of the nanoparticles is incorporated in the flow model. The equations governing the nanofluid flow are modeled and exact solutions are managed under long wavelength and flow Reynolds number and long wavelength approximations. Explicit expressions of axial velocity, stream function, microrotation, nanoparticle temperature, and concentration have been derived. The phenomena of shear stress and trapping have also been discussed. Finally, the influences of various parameters of interest on flow variables have been discussed numerically and explained graphically. Besides, the results obtained in this paper will be helpful to those who are working on the development of various realms like fluid mechanics, the rotation, Brownian motion, thermophoresis, coupling number, micropolar parameter, and the nondimensional geometry parameters. PMID:27688703

  2. wall

    Directory of Open Access Journals (Sweden)

    Irshad Kashif

    2016-01-01

    Full Text Available Maintaining indoor climatic conditions of buildings compatible with the occupant comfort by consuming minimum energy, especially in a tropical climate becomes a challenging problem for researchers. This paper aims to investigate this problem by evaluating the effect of different kind of Photovoltaic Trombe wall system (PV-TW on thermal comfort, energy consumption and CO2 emission. A detailed simulation model of a single room building integrated with PV-TW was modelled using TRNSYS software. Results show that 14-35% PMV index and 26-38% PPD index reduces as system shifted from SPV-TW to DGPV-TW as compared to normal buildings. Thermal comfort indexes (PMV and PPD lie in the recommended range of ASHARE for both DPV-TW and DGPV-TW except for the few months when RH%, solar radiation intensity and ambient temperature were high. Moreover PVTW system significantly reduces energy consumption and CO2 emission of the building and also 2-4.8 °C of temperature differences between indoor and outdoor climate of building was examined.

  3. Effect of a pinning field on the critical current density for current-induced domain wall motion in perpendicular magnetic anisotropy nanowires.

    Science.gov (United States)

    Ooba, Ayaka; Fujimura, Yuma; Takahashi, Kota; Komine, Takashi; Sugita, Ryuji

    2012-09-01

    In this study, the effect of a pinning field on the critical current density for current-induced domain wall motion in nanowires with perpendicular magnetic anisotropy was investigated using micromagnetic simulations. In order to estimate the pinning field in notched nanowires, we conducted wall energy calculations for nanowires with various saturation magnetizations. The pinning field increased as the notch size increased. The pinning field decreased as the saturation magnetization decreased. As a result, the decreased in the pinning field causes the reduction of the critical current density. Therefore, a significant reduction of the critical current density can be obtained by decreasing the saturation magnetization, even if wall pinning occurs.

  4. Interaction of Streamwise and Wall-Normal Velocities in Combined Wave-Current Motion

    Institute of Scientific and Technical Information of China (English)

    Shu-Qing YANG; In-Soo KIM; Daniel S. KOH; Young-Chae SONG

    2005-01-01

    The aim of this paper is to present an analytical expression for the streamwise velocity distribution in a non-uniform flow in the presence of waves; the correlation between the horizontal and vertical velocity components has been comprehensively examined. Different from previous researches which attributed the deviation of velocity from the classical log-law to the wave Reynolds stress, i.e. -ρ(uv)only, this study demonstrates that the momentum flux caused by mean velocities, i.e.,(u)and(v) , is also responsible for the velocity deviation, and it is found that the streamwise velocity for a flow in the presence of non-zero wall-normal velocity does not follow the classical log-law, but the modified log-law proposed in this study based on simplified mixing-length theorem. The validity of the modified log-law has been verified by use of available experimental data from published sources for combined wave-current flows, and good agreement between the predicted and observed velocity profiles has been achieved.

  5. Separating spin torque and heating effects in current-induced domain wall motion probed by high-resolution transmission electron microscopy

    DEFF Research Database (Denmark)

    Junginger, F.; Klaeui, M.; Backes, D.

    2007-01-01

    Observations of domain wall motion and transformations due to injected current pulses in permalloy zigzag structures using off-axis electron holography and Lorentz microscopy are reported. Heating on membranes leads to thermally activated random behavior at low current densities and by backcoating...

  6. Nonverbal Synchrony in Social Interactions of Patients with Schizophrenia Indicates Socio-Communicative Deficits.

    Science.gov (United States)

    Kupper, Zeno; Ramseyer, Fabian; Hoffmann, Holger; Tschacher, Wolfgang

    2015-01-01

    Disordered interpersonal communication can be a serious problem in schizophrenia. Recent advances in computer-based measures allow reliable and objective quantification of nonverbal behavior. Research using these novel measures has shown that objective amounts of body and head movement in patients with schizophrenia during social interactions are closely related to the symptom profiles of these patients. In addition to and above mere amounts of movement, the degree of synchrony, or imitation, between patients and normal interactants may be indicative of core deficits underlying various problems in domains related to interpersonal communication, such as symptoms, social competence, and social functioning. Nonverbal synchrony was assessed objectively using Motion Energy Analysis (MEA) in 378 brief, videotaped role-play scenes involving 27 stabilized outpatients diagnosed with paranoid-type schizophrenia. Low nonverbal synchrony was indicative of symptoms, low social competence, impaired social functioning, and low self-evaluation of competence. These relationships remained largely significant when correcting for the amounts of patients' movement. When patients showed reduced imitation of their interactants' movements, negative symptoms were likely to be prominent. Conversely, positive symptoms were more prominent in patients when their interaction partners' imitation of their movements was reduced. Nonverbal synchrony can be an objective and sensitive indicator of the severity of patients' problems. Furthermore, quantitative analysis of nonverbal synchrony may provide novel insights into specific relationships between symptoms, cognition, and core communicative problems in schizophrenia.

  7. Nonverbal Synchrony in Social Interactions of Patients with Schizophrenia Indicates Socio-Communicative Deficits.

    Directory of Open Access Journals (Sweden)

    Zeno Kupper

    Full Text Available Disordered interpersonal communication can be a serious problem in schizophrenia. Recent advances in computer-based measures allow reliable and objective quantification of nonverbal behavior. Research using these novel measures has shown that objective amounts of body and head movement in patients with schizophrenia during social interactions are closely related to the symptom profiles of these patients. In addition to and above mere amounts of movement, the degree of synchrony, or imitation, between patients and normal interactants may be indicative of core deficits underlying various problems in domains related to interpersonal communication, such as symptoms, social competence, and social functioning.Nonverbal synchrony was assessed objectively using Motion Energy Analysis (MEA in 378 brief, videotaped role-play scenes involving 27 stabilized outpatients diagnosed with paranoid-type schizophrenia.Low nonverbal synchrony was indicative of symptoms, low social competence, impaired social functioning, and low self-evaluation of competence. These relationships remained largely significant when correcting for the amounts of patients' movement. When patients showed reduced imitation of their interactants' movements, negative symptoms were likely to be prominent. Conversely, positive symptoms were more prominent in patients when their interaction partners' imitation of their movements was reduced.Nonverbal synchrony can be an objective and sensitive indicator of the severity of patients' problems. Furthermore, quantitative analysis of nonverbal synchrony may provide novel insights into specific relationships between symptoms, cognition, and core communicative problems in schizophrenia.

  8. How interpersonal synchrony facilitates early prosocial behavior.

    Science.gov (United States)

    Cirelli, Laura K

    2017-08-09

    When infants and children affiliate with others, certain cues may direct their social efforts to 'better' social partners. Interpersonal synchrony, or when two or more people move together in time, can be one such cue. In adults, experiencing interpersonal synchrony encourages affiliative behaviors. Recent studies have found that these effects also influence early prosociality-for example, 14-month-olds help a synchronous partner more than an asynchronous partner. These effects on helping are specifically directed to the synchronous movement partner and members of that person's social group. In older children, the prosocial effects of interpersonal synchrony may even cross group divides. How synchrony and other cues for group membership influence early prosociality is a promising avenue for future research. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Detection of postischemic regional left ventricular delayed outward wall motion or diastolic stunning after exercise-induced ischemia in patients with stable effort angina by using color kinesis.

    Science.gov (United States)

    Ishii, Katsuhisa; Miwa, Kunihisa; Sakurai, Takahiro; Kataoka, Kazuaki; Imai, Makoto; Kintaka, Aya; Aoyama, Takeshi; Kawanami, Masaki

    2008-04-01

    To determine whether postischemic diastolic stunning could be detected using color kinesis, we evaluated regional left ventricular (LV) diastolic wall motion in 36 patients with stable effort angina and a coronary stenosis (> or = 70% of luminal diameter), and in 30 control subjects. Regional LV filling fraction in the short-axis view during the first 30% of the LV filling time (color kinesis diastolic index) was determined before, 20 minutes, 1 hour, and 24 hours after the treadmill exercise test. In 33 of the 36 patients (92%), new regional LV delayed outward motion during early diastole (color kinesis diastolic index < or = 40%) was detected at 20 minutes after exercise. The regional LV delayed diastolic wall motion showed significant improvement but persisted 1 hour afterward in 20 of 36 patients (56%), and disappeared 24 hours after exercise. Detection of regional stunned myocardium with impaired diastolic function may be a useful tool for the diagnosis of coronary artery disease.

  10. Controlling magnetic domain wall motion in the creep regime in He{sup +}-irradiated CoFeB/MgO films with perpendicular anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Herrera Diez, L., E-mail: liza.herrera-diez@ief.u-psud.fr; García-Sánchez, F.; Adam, J.-P.; Devolder, T.; Eimer, S.; El Hadri, M. S.; Ravelosona, D. [Institut d' Electronique Fondamentale, Université Paris-Sud, UMR CNRS 8622, 91405 Orsay (France); Lamperti, A.; Mantovan, R. [Laboratorio MDM, IMM-CNR, Via C. Olivetti 2, 20864 Agrate (MB) (Italy); Ocker, B. [Singulus Technology AG, Hanauer Landstrasse 103, 63796 Kahl am Main (Germany)

    2015-07-20

    This study presents the effective tuning of perpendicular magnetic anisotropy in CoFeB/MgO thin films by He{sup +} ion irradiation and its effect on domain wall motion in a low field regime. Magnetic anisotropy and saturation magnetisation are found to decrease as a function of the irradiation dose which can be related to the observed irradiation-induced changes in stoichiometry at the CoFeB/MgO interface. These changes in the magnetic intrinsic properties of the film are reflected in the domain wall dynamics at low magnetic fields (H) where irradiation is found to induce a significant decrease in domain wall velocity (v). For all irradiation doses, domain wall velocities at low fields are well described by a creep law, where Ln(v) vs. H{sup −1∕4} behaves linearly, up to a maximum field H*, which has been considered as an approximation to the value of the depinning field H{sub dep}. In turn, H* ≈ H{sub dep} is seen to increase as a function of the irradiation dose, indicating an irradiation-induced extension of the creep regime of domain wall motion.

  11. Roles of the magnetic field and electric current in thermally activated domain wall motion in a submicrometer magnetic strip with perpendicular magnetic anisotropy.

    Science.gov (United States)

    Emori, Satoru; Beach, Geoffrey S D

    2012-01-18

    We have experimentally studied micrometer-scale domain wall (DW) motion driven by a magnetic field and an electric current in a Co/Pt multilayer strip with perpendicular magnetic anisotropy. The thermal activation energy for DW motion, along with its scaling with the driving field and current, has been extracted directly from the temperature dependence of the DW velocity. The injection of DC current resulted in an enhancement of the DW velocity independent of the current polarity, but produced no measurable change in the activation energy barrier. Through this analysis, the observed current-induced DW velocity enhancement can be entirely and unambiguously attributed to Joule heating.

  12. Population synchrony in small-world networks.

    Science.gov (United States)

    Ranta, Esa; Fowler, Mike S; Kaitala, Veijo

    2008-02-22

    Network topography ranges from regular graphs (linkage between nearest neighbours only) via small-world graphs (some random connections between nodes) to completely random graphs. Small-world linkage is seen as a revolutionary architecture for a wide range of social, physical and biological networks, and has been shown to increase synchrony between oscillating subunits. We study small-world topographies in a novel context: dispersal linkage between spatially structured populations across a range of population models. Regular dispersal between population patches interacting with density-dependent renewal provides one ecological explanation for the large-scale synchrony seen in the temporal fluctuations of many species, for example, lynx populations in North America, voles in Fennoscandia and grouse in the UK. Introducing a small-world dispersal kernel leads to a clear reduction in synchrony with both increasing dispersal rate and small-world dispersal probability across a variety of biological scenarios. Synchrony is also reduced when populations are affected by globally correlated noise. We discuss ecological implications of small-world dispersal in the frame of spatial synchrony in population fluctuations.

  13. Abnormal brain synchrony in Down Syndrome☆

    Science.gov (United States)

    Anderson, Jeffrey S.; Nielsen, Jared A.; Ferguson, Michael A.; Burback, Melissa C.; Cox, Elizabeth T.; Dai, Li; Gerig, Guido; Edgin, Jamie O.; Korenberg, Julie R.

    2013-01-01

    Down Syndrome is the most common genetic cause for intellectual disability, yet the pathophysiology of cognitive impairment in Down Syndrome is unknown. We compared fMRI scans of 15 individuals with Down Syndrome to 14 typically developing control subjects while they viewed 50 min of cartoon video clips. There was widespread increased synchrony between brain regions, with only a small subset of strong, distant connections showing underconnectivity in Down Syndrome. Brain regions showing negative correlations were less anticorrelated and were among the most strongly affected connections in the brain. Increased correlation was observed between all of the distributed brain networks studied, with the strongest internetwork correlation in subjects with the lowest performance IQ. A functional parcellation of the brain showed simplified network structure in Down Syndrome organized by local connectivity. Despite increased interregional synchrony, intersubject correlation to the cartoon stimuli was lower in Down Syndrome, indicating that increased synchrony had a temporal pattern that was not in response to environmental stimuli, but idiosyncratic to each Down Syndrome subject. Short-range, increased synchrony was not observed in a comparison sample of 447 autism vs. 517 control subjects from the Autism Brain Imaging Exchange (ABIDE) collection of resting state fMRI data, and increased internetwork synchrony was only observed between the default mode and attentional networks in autism. These findings suggest immature development of connectivity in Down Syndrome with impaired ability to integrate information from distant brain regions into coherent distributed networks. PMID:24179822

  14. Somatosensory driven interpersonal synchrony during rhythmic sway.

    Science.gov (United States)

    Sofianidis, George; Hatzitaki, Vassilia; Grouios, George; Johannsen, Leif; Wing, Alan

    2012-06-01

    Spontaneous synchrony emerges between individuals performing together rhythmic activities while communicating by means of sensory feedback. In this study, we examined the nature of interpersonal synchrony mediated by light fingertip contact when individuals sway rhythmically in the sagittal plane. The effect of traditional dance expertise on interpersonal synchrony was investigated. Sixty participants (30 dancers, 30 novices) formed three types of couples (10 expert couples, 10 novice couples, 10 mixed couples) and performed a rhythmical sway task (40s) that was either self or metronome paced (frequency: 0.25Hz). Cross spectral analysis of the center of pressure (CoP) displacement signals revealed that during self-paced sway fingertip contact evoked a decrease of the dominant sway frequency difference between partners, an increase in the coherence between the sway signals and a concentration of relative phase angles towards the in-phase (0°-20°) region. In metronome paced sway however, only expert dancers were able to benefit from haptic contact to further improve interpersonal synchrony. These findings suggest that haptic contact can stabilize the spontaneous coordination dynamics of two persons performing rhythmic sway together. The strength of the emerged synchrony depends on the individuals' expertise to integrate tactile and auditory information about sway.

  15. [Asynchronous wall motion in patients with ischemic heart disease assessed by higher-order harmonics of the Fourier series].

    Science.gov (United States)

    Kodama, S; Tamaki, N; Mukai, T; Yonekura, Y; Torizuka, K; Suzuki, Y; Tamaki, S; Nohara, R; Kambara, H; Kawai, C

    1986-01-01

    To assess regional cardiac function in patients with ischemic heart disease (IHD), multigated blood-pool studies using higher-order harmonics of the Fourier series were performed for 14 normal persons and 37 patients with IHD. IHD was further divided into IHD (I) (EF greater than or equal to 50%) and IHD (II) (EF less than 50%). A pixel-by-pixel volume curve was simulated using second order harmonics of the Fourier series to create functional images of the following parameters: time to endosystole (TES), peak ejection rate (PER), time to PER (TPE), peak filling rate (PFR), and time to PFR (TPF). TES (SD), TPE (SD), and TPF (SD) were calculated as the standard deviations of left ventricular (LV) histograms of each phase, representing indexes of asynchronous wall motion. An LV volume curve was simulated using third order harmonics to calculate PFR, PFR/PER, and TPF/TPE, representing indexes of diastolic function. TES (SD) was abnormal in 10 cases (50%), and TPE (SD) was abnormal in seven cases (35%) of IHD (II). On the contrary, TPF (SD) was abnormal in three cases (18%) of IHD (I) and 15 cases (75%) of IHD (II), indicating that diastolic asynchronous indexes are more sensitive than systolic asynchronous indexes in detecting IHD. IHD (I) and IHD (II) showed lower PFR (2.32 +/- 0.55, 1.64 +/- 0.46 EDV/sec) and lower PFR/PER (0.84 +/- 0.15, 0.68 +/- 0.26) than those in normals (3.25 +/- 0.98 EDV/sec, 0.99 +/- 0.19), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

  16. Automated grading of left ventricular segmental wall motion by an artificial neural network using color kinesis images

    Directory of Open Access Journals (Sweden)

    L.O. Murta Jr.

    2006-01-01

    Full Text Available The present study describes an auxiliary tool in the diagnosis of left ventricular (LV segmental wall motion (WM abnormalities based on color-coded echocardiographic WM images. An artificial neural network (ANN was developed and validated for grading LV segmental WM using data from color kinesis (CK images, a technique developed to display the timing and magnitude of global and regional WM in real time. We evaluated 21 normal subjects and 20 patients with LVWM abnormalities revealed by two-dimensional echocardiography. CK images were obtained in two sets of viewing planes. A method was developed to analyze CK images, providing quantitation of fractional area change in each of the 16 LV segments. Two experienced observers analyzed LVWM from two-dimensional images and scored them as: 1 normal, 2 mild hypokinesia, 3 moderate hypokinesia, 4 severe hypokinesia, 5 akinesia, and 6 dyskinesia. Based on expert analysis of 10 normal subjects and 10 patients, we trained a multilayer perceptron ANN using a back-propagation algorithm to provide automated grading of LVWM, and this ANN was then tested in the remaining subjects. Excellent concordance between expert and ANN analysis was shown by ROC curve analysis, with measured area under the curve of 0.975. An excellent correlation was also obtained for global LV segmental WM index by expert and ANN analysis (R² = 0.99. In conclusion, ANN showed high accuracy for automated semi-quantitative grading of WM based on CK images. This technique can be an important aid, improving diagnostic accuracy and reducing inter-observer variability in scoring segmental LVWM.

  17. Automated grading of left ventricular segmental wall motion by an artificial neural network using color kinesis images.

    Science.gov (United States)

    Murta, L O; Ruiz, E E S; Pazin-Filho, A; Schmidt, A; Almeida-Filho, O C; Simões, M V; Marin-Neto, J A; Maciel, B C

    2006-01-01

    The present study describes an auxiliary tool in the diagnosis of left ventricular (LV) segmental wall motion (WM) abnormalities based on color-coded echocardiographic WM images. An artificial neural network (ANN) was developed and validated for grading LV segmental WM using data from color kinesis (CK) images, a technique developed to display the timing and magnitude of global and regional WM in real time. We evaluated 21 normal subjects and 20 patients with LVWM abnormalities revealed by two-dimensional echocardiography. CK images were obtained in two sets of viewing planes. A method was developed to analyze CK images, providing quantitation of fractional area change in each of the 16 LV segments. Two experienced observers analyzed LVWM from two-dimensional images and scored them as: 1) normal, 2) mild hypokinesia, 3) moderate hypokinesia, 4) severe hypokinesia, 5) akinesia, and 6) dyskinesia. Based on expert analysis of 10 normal subjects and 10 patients, we trained a multilayer perceptron ANN using a back-propagation algorithm to provide automated grading of LVWM, and this ANN was then tested in the remaining subjects. Excellent concordance between expert and ANN analysis was shown by ROC curve analysis, with measured area under the curve of 0.975. An excellent correlation was also obtained for global LV segmental WM index by expert and ANN analysis (R2 = 0.99). In conclusion, ANN showed high accuracy for automated semi-quantitative grading of WM based on CK images. This technique can be an important aid, improving diagnostic accuracy and reducing inter-observer variability in scoring segmental LVWM.

  18. Longitudinal peak strain detects a smaller risk area than visual assessment of wall motion in acute myocardial infarction

    Directory of Open Access Journals (Sweden)

    Brudin Lars

    2010-01-01

    Full Text Available Abstract Background Opening of an occluded infarct related artery reduces infarct size and improves survival in acute ST-elevation myocardial infarction (STEMI. In this study we performed tissue Doppler analysis (peak strain, displacement, mitral annular movement (MAM and compared with visual assessment for the study of the correlation of measurements of global, regional and segmental function with final infarct size and transmurality. In addition, myocardial risk area was determined and a prediction sought for the development of infarct transmurality ≥50%. Methods Twenty six patients with STEMI submitted for primary percutaneous coronary intervention (PCI were examined with echocardiography on the catheterization table. Four to eight weeks later repeat echocardiography was performed for reassessment of function and magnetic resonance imaging for the determination of final infarct size and transmurality. Results On a global level, wall motion score index (WMSI, ejection fraction (EF, strain, and displacement all showed significant differences (p ≤ 0.001, p ≤ 0.001, p ≤ 0.001 and p = 0.03 between the two study visits, but MAM did not (p = 0.17. On all levels (global, regional and segmental and both pre- and post PCI, WMSI showed a higher correlation with scar transmurality compared to strain. We found that both strain and WMSI predicted the development of scar transmurality ≥50%, but strain added no significant information to that obtained with WMSI in a logistic regression analysis. Conclusions In patients with acute STEMI, WMSI, EF, strain, and displacement showed significant changes between the pre- and post PCI exam. In a ROC-analysis, strain had 64% sensitivity at 80% specificity and WMSI around 90% sensitivity at 80% specificity for the detection of scar with transmurality ≥50% at follow-up.

  19. Effects of non-invasive ventilation and posture on chest wall volumes and motion in patients with amyotrophic lateral sclerosis: a case series

    Directory of Open Access Journals (Sweden)

    Cristiana M. Magalhães

    2016-01-01

    Full Text Available ABSTRACT Background The effects of non-invasive ventilation (NIV on the breathing pattern and thoracoabdominal motion of patients with amyotrophic lateral sclerosis (ALS are unknown. Objectives 1 To analyze the influence of NIV on chest wall volumes and motion assessed by optoelectronic plethysmography in ALS patients and 2 to compare these parameters in the supine and sitting positions to those of healthy individuals (without NIV. Method Nine ALS patients were evaluated in the supine position using NIV. In addition, the ALS patients and nine healthy individuals were evaluated in both sitting and supine positions. Statistical analysis was performed using the paired Student t-test or Wilcoxon test and the Student t-test for independent samples or Mann-Whitney U test. Results Chest wall volume increased significantly with NIV, mean volume=0.43 (SD=0.16L versus 0.57 (SD=0.19L (p=0.04. No significant changes were observed for the pulmonary rib cage, abdominal rib cage, or abdominal contribution. The index of the shortening velocity of the diaphragmatic muscle, mean=0.15 (SD=0.05L/s versus 0.21 (SD=0.05L/s (p<0.01, and abdominal muscles, mean=0.09 (SD=0.02L/s versus 0.14 (SD=0.06L/s (p<0.01, increased during NIV. Comparisons between the supine and sitting positions showed similar changes in chest wall motion in both groups. However, the ALS patients presented a significantly lower contribution of the abdomen in the supine position compared with the controls, mean=56 (SD=13 versus 69 (SD=10 (p=0.02. Conclusions NIV improved chest wall volumes without changing the contribution of the chest wall compartment in ALS patients. In the supine position, ALS patients had a lower contribution of the abdomen, which may indicate early diaphragmatic dysfunction.

  20. Synchrony in embryogenesis via an active medium

    Science.gov (United States)

    McIsaac, R. Scott; Sengupta, Anirvan; Wingreen, Ned

    2009-03-01

    In developing embryos of the frog Xenopus, mitotic divisions occur at 8-minute intervals. After the initial rounds of division, nuclei divide in near-perfect synchrony throughout the embryo. Given a typical protein diffusion constant of 10 μm^2sec, and an embryo length of 1mm, it would take diffusion many hours to propagate a signal across the embryo. Therefore, synchrony cannot be attained by diffusion alone. We hypothesize that known autocatalytic reactions of cell-cycle components make the embryo an ``active medium'' in which waves propagate much faster than diffusion, enforcing synchrony. Furthermore, developing embryos are found to be very robust, meaning that their spatial and temporal patterns are highly repeatable over a broad range of environmental conditions and despite biochemical noise. We report on robust synchronization of oscillations for a coupled two-species system consisting of diffusing activator and repressor molecules.

  1. Current-driven domain wall motion due to volume spin transfer torque in Co/Ni multilayer systems on Au underlayer

    Science.gov (United States)

    Ryu, Kwang-Su; Yang, See-Hun; Thomas, Luc; Parkin, Stuart

    2016-09-01

    We have studied the current-induced domain wall (CIDW) dynamics in perpendicularly magnetized Co/Ni multilayers deposited on Au underlayer, where the conventional spin transfer torque governs the domain wall dynamics, by the Kerr microscope. It is found that the DW angle tilting following Oersted field profile plays an important role in domain wall (DW) motion at high current density J by decreasing DW velocity with the increasing J, while distorting its DW morphology. Also we find that the DW pinning becomes pronounced as the anisotropy decreases by increasing number of Co/Ni repeats. Most remarkably, the DW tilting angle changes its sign by inserting ultrathin Pt layer between Au and Co layer, which suggests that the Dzyaloshinskii-Moriya interaction and spin Hall effect induces opposite effect in DW tilting. Our findings can be of use for application of CIDW to spintronics with perpendicularly magnetized systems.

  2. Learning of Syllable-Object Relations by Preverbal Infants: The Role of Temporal Synchrony and Syllable Distinctiveness

    Science.gov (United States)

    Gogate, Lakshmi J.

    2010-01-01

    The role of temporal synchrony and syllable distinctiveness in preverbal infants' learning of word-object relations was investigated. In Experiment 1, 7- and 8-month-olds (N=64) were habituated under conditions where two "similar-sounding" syllables, /tah/ and /gah/, were spoken simultaneously with the motions of one of two sets of…

  3. The dynamics of the asymmetric motion of domain walls of sandwich domain structure in a Fe-based amorphous ribbon

    Energy Technology Data Exchange (ETDEWEB)

    Zhmetko, D.N., E-mail: sergey.zhmetko@gmail.com [Department of Physics, Zaporizhzhya National University, 66 Zhukovsky Street, 69063 Zaporizhzhya (Ukraine); Zhmetko, S.D. [Department of Physics, Zaporizhzhya National University, 66 Zhukovsky Street, 69063 Zaporizhzhya (Ukraine); Troschenkov, Y.N. [Institute for Magnetism, 36-b Vernadsky Boulevard, 03142 Kyiv (Ukraine); Matsura, A.V. [Department of Physics, Zaporizhzhya National University, 66 Zhukovsky Street, 69063 Zaporizhzhya (Ukraine)

    2013-08-15

    The frequency dependence of asymmetry of the domain walls velocity relative to the middle plane of amorphous ribbon is investigated. An additional pressure of the same direction acting on each domain wall caused by dependence of eddy current damping on the coordinate of the domain wall is revealed. The microscopic mechanisms of this additional pressure are considered. - Highlights: ► Additional pressure on the domain wall, caused by inhomogeneity of its damping. ► Asymmetry of the coordinate of the nucleation of domain walls and their damping. ► Connection between the components of additional pressure and its direction. ► Interaction of domain walls with the surface defects of the amorphous ribbon.

  4. Synchrony and neural coding in cerebellar circuits

    Directory of Open Access Journals (Sweden)

    Abigail L Person

    2012-12-01

    Full Text Available The cerebellum regulates complex movements and is also implicated in cognitive tasks, and cerebellar dysfunction is consequently associated not only with movement disorders, but also with conditions like autism and dyslexia. How information is encoded by specific cerebellar firing patterns remains debated, however. A central question is how the cerebellar cortex transmits its integrated output to the cerebellar nuclei via GABAergic synapses from Purkinje neurons. Possible answers come from accumulating evidence that subsets of Purkinje cells synchronize their firing during behaviors that require the cerebellum. Consistent with models predicting that coherent activity of inhibitory networks has the capacity to dictate firing patterns of target neurons, recent experimental work supports the idea that inhibitory synchrony may regulate the response of cerebellar nuclear cells to Purkinje inputs, owing to the interplay between unusually fast inhibitory synaptic responses and high rates of intrinsic activity. Data from multiple laboratories lead to a working hypothesis that synchronous inhibitory input from Purkinje cells can set the timing and rate of action potentials produced by cerebellar nuclear cells, thereby relaying information out of the cerebellum. If so, then changing spatiotemporal patterns of Purkinje activity would allow different subsets of inhibitory neurons to control cerebellar output at different times. Here we explore the evidence for and against the idea that a synchrony code defines, at least in part, the input-output function between the cerebellar cortex and nuclei. We consider the literature on the existence of simple spike synchrony, convergence of Purkinje neurons onto nuclear neurons, and intrinsic properties of nuclear neurons that contribute to responses to inhibition. Finally, we discuss factors that may disrupt or modulate a synchrony code and describe the potential contributions of inhibitory synchrony to other motor

  5. Validation of a novel modified wall motion score for estimation of left ventricular ejection fraction in ischemic and non-ischemic cardiomyopathy

    Energy Technology Data Exchange (ETDEWEB)

    Scholl, David, E-mail: David.Scholl@utoronto.ca [Imaging Research Laboratories, Robarts Research Institute, London, Ontario (Canada); Kim, Han W., E-mail: hanwkim@gmail.com [Duke Cardiovascular Magnetic Resonance Center, Division of Cardiology, Duke University, NC (United States); Shah, Dipan, E-mail: djshah@tmhs.org [The Methodist DeBakey Heart Center, Houston, TX (United States); Fine, Nowell M., E-mail: nowellfine@gmail.com [Division of Cardiology, Department of Medicine, Schulich School of Medicine and Dentistry, University of Western Ontario (Canada); Tandon, Shruti, E-mail: standon4@uwo.ca [Division of Cardiology, Department of Medicine, Schulich School of Medicine and Dentistry, University of Western Ontario (Canada); Thompson, Terry, E-mail: thompson@lawsonimaging.ca [Lawson Health Research Institute, London, Ontario (Canada); Department of Medical Biophysics, University of Western Ontario, London, Ontario (Canada); Drangova, Maria, E-mail: mdrangov@imaging.robarts.ca [Imaging Research Laboratories, Robarts Research Institute, London, Ontario (Canada); Department of Medical Biophysics, University of Western Ontario, London, Ontario (Canada); White, James A., E-mail: jwhite@imaging.robarts.ca [Division of Cardiology, Department of Medicine, Schulich School of Medicine and Dentistry, University of Western Ontario (Canada); Lawson Health Research Institute, London, Ontario (Canada); Imaging Research Laboratories, Robarts Research Institute, London, Ontario (Canada)

    2012-08-15

    Background: Visual determination of left ventricular ejection fraction (LVEF) by segmental scoring may be a practical alternative to volumetric analysis of cine magnetic resonance imaging (MRI). The accuracy and reproducibility of this approach for has not been described. The purpose of this study was to validate a novel segmental visual scoring method for LVEF estimation using cine MRI. Methods: 362 patients with known or suspected cardiomyopathy were studied. A modified wall motion score (mWMS) was used to blindly score the wall motion of all cardiac segments from cine MRI imaging. The same datasets were subjected to blinded volumetric analysis using endocardial contour tracing. The population was then separated into a model cohort (N = 181) and validation cohort (N = 181), with the former used to derive a regression equation of mWMS versus true volumetric LVEF. The validation cohort was then used to test the accuracy of this regression model to estimate the true LVEF from a visually determined mWMS. Reproducibility testing of mWMS scoring was performed upon a randomly selected sample of 20 cases. Results: The regression equation relating mWMS to true LVEF in the model cohort was: LVEF = 54.23 - 0.5761 Multiplication-Sign mWMS. In the validation cohort this equation produced a strong correlation between mWMS-derived LVEF and true volumetric LVEF (r = 0.89). Bland and Altman analysis showed no systematic bias in the LVEF estimated using the mWMS (-0.3231%, 95% limits of agreement -12.22% to 11.58%). Inter-observer and intra-observer reproducibility was excellent (r = 0.93 and 0.97, respectively). Conclusion: The mWMS is a practical tool for reporting regional wall motion and provides reproducible estimates of LVEF from cine MRI.

  6. Enhancing "theory of mind" through behavioral synchrony.

    Science.gov (United States)

    Baimel, Adam; Severson, Rachel L; Baron, Andrew S; Birch, Susan A J

    2015-01-01

    Theory of mind refers to the abilities underlying the capacity to reason about one's own and others' mental states. This ability is critical for predicting and making sense of the actions of others, is essential for efficient communication, fosters social learning, and provides the foundation for empathic concern. Clearly, there is incredible value in fostering theory of mind. Unfortunately, despite being the focus of a wealth of research over the last 40 years relatively little is known about specific strategies for fostering social perspective taking abilities. We provide a discussion of the rationale for applying one specific strategy for fostering efficient theory of mind-that of engaging in "behavioral synchrony" (i.e., the act of keeping together in time with others). Culturally evolved collective rituals involving synchronous actions have long been held to act as social glue. Specifically, here we present how behavioral synchrony tunes our minds for reasoning about other minds in the process of fostering social coordination and cooperation, and propose that we can apply behavioral synchrony as a tool for enhancing theory of mind.

  7. Signatures of synchrony in pairwise count correlations

    Directory of Open Access Journals (Sweden)

    Tatjana Tchumatchenko

    2010-04-01

    Full Text Available Concerted neural activity can reflect specific features of sensory stimuli or behavioral tasks. Correlation coefficients and count correlations are frequently used to measure correlations between neurons, design synthetic spike trains and build population models. But are correlation coefficients always a reliable measure of input correlations? Here, we consider a stochastic model for the generation of correlated spike sequences which replicate neuronal pairwise correlations in many important aspects. We investigate under which conditions the correlation coefficients reflect the degree of input synchrony and when they can be used to build population models. We find that correlation coefficients can be a poor indicator of input synchrony for some cases of input correlations. In particular, count correlations computed for large time bins can vanish despite the presence of input correlations. These findings suggest that network models or potential coding schemes of neural population activity need to incorporate temporal properties of correlated inputs and take into consideration the regimes of firing rates and correlation strengths to ensure that their building blocks are an unambiguous measures of synchrony.

  8. Hierarchical Synchrony of Phase Oscillators in Modular Networks

    CERN Document Server

    Skardal, Per Sebastian

    2011-01-01

    We study synchronization of sinusoidally coupled phase oscillators on networks with modular structure and a large number of oscillators in each community. Of particular interest is the hierarchy of local and global synchrony, i.e., synchrony within and between communities, respectively. Using the recent ansatz of Ott and Antonsen, we find that the degree of local synchrony can be determined from a set of coupled low-dimensional equations. If the number of communities in the network is large, a low-dimensional description of global synchrony can be also found. Using these results, we study bifurcations between different types of synchrony. We find that, depending on the relative strength of local and global coupling, the transition to synchrony in the network can be mediated by local or global effects.

  9. Manipulation of multiple 360o domain wall structures and its current-driven motion in a magnetic nanostripe

    Directory of Open Access Journals (Sweden)

    Wenjun Dong

    2015-11-01

    Full Text Available Dynamics of multiple transverse walls (TWs in a magnetic nanostripe is studied by micromagnetic simulations. It shows that, when TWs are arranged in a stripe with same orientation, they will attract each other and finally annihilate. However, when adjacent TWs are arranged with opposite orientation, a metastable complex wall can be formed, e.g., two TWs lead to 360o wall. For three or more TWs, the formed complex wall includes a number of 360o substructures, which is called multiple 360o structure (M360S here. The M360S itself may be used to store multiple logical data since each 360o substructure can act as logical ”0” or ”1”. On the other hand, the M360S may behave like single TW under an applied current, namely, the M360S can be driven steadily by current like that of single TW. A parity effect of the number of 360o substructures on the critical current for the annihilation is found. Namely, when the number is odd or even, the critical current increase or decrease with the increasing of the number, respectively. The parity effect is relevant to the out-of-plane magnetic moment of the M360S.

  10. Analytical solution of the strain-controlled magnetic domain wall motion in bilayer piezoelectric/magnetostrictive nanostructures

    Science.gov (United States)

    Consolo, Giancarlo; Valenti, Giovanna

    2017-01-01

    The one-dimensional propagation of magnetic domain walls in an isotropic, linearly elastic, magnetostrictive material is investigated in the framework of the extended Landau-Lifshitz-Gilbert equation where the effects of a spin-polarized current and a rate-independent dry-friction dissipation are taken into account. In our analysis, it is assumed that the ferromagnet is subject to a spatially uniform biaxial in-plain stress generated by a piezoelectric substrate combined with the former in a multiferroic heterostructure. Moreover, a possible connection between the dry-friction mechanism and the piezo-induced strains is conjectured. By adopting the traveling waves ansatz, the effect of such a stress on the domain wall dynamics is explored in both steady and precessional regimes. In particular, it is proved that the magnetoelastic contribution, while it does not formally modify the classical solution, affects both the propagation threshold and the Walker Breakdown conditions involved in the steady regime, in agreement with recent experimental results. In the precessional regime, it is shown that the existence of a correlation between the piezo-induced strains and dry-friction leads to an upward shift of the domain wall velocity.

  11. Slow Motion of a Sphere Away from a Wall: Effect of Surface Roughness on the Viscous Force

    Indian Academy of Sciences (India)

    Sunil Datta; Manju Shukla

    2002-11-01

    An asymptotic analysis is given for the effect of roughness exhibited through the slip parameter on the motion of the sphere, moving away from a plane surface with velocity . The method replaces the no-slip condition at the rough surface by slip condition and employs the method of inner and outer regions on the sphere surface. For > 0, we have the classical slip boundary condition and the results of the paper are then of interest in the microprocessor industry.

  12. Real-time ultrasound-tagging to track the 2D motion of the common carotid artery wall in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Zahnd, Guillaume, E-mail: g.zahnd@erasmusmc.nl [Biomedical Imaging Group Rotterdam, Departments of Radiology and Medical Informatics, Erasmus MC, Rotterdam 3000 CA (Netherlands); Salles, Sébastien; Liebgott, Hervé; Vray, Didier [Université de Lyon, CREATIS, CNRS UMR 5220, INSERM U1044, INSA-Lyon, Université Lyon 1, Lyon 69100 (France); Sérusclat, André [Department of Radiology, Louis Pradel Hospital, Lyon 69500 (France); Moulin, Philippe [Department of Endocrinology, Louis Pradel Hospital, Hospices Civils de Lyon, Université Lyon 1, Lyon 69100, France and INSERM UMR 1060, Lyon 69500 (France)

    2015-02-15

    Purpose: Tracking the motion of biological tissues represents an important issue in the field of medical ultrasound imaging. However, the longitudinal component of the motion (i.e., perpendicular to the beam axis) remains more challenging to extract due to the rather coarse resolution cell of ultrasound scanners along this direction. The aim of this study is to introduce a real-time beamforming strategy dedicated to acquire tagged images featuring a distinct pattern in the objective to ease the tracking. Methods: Under the conditions of the Fraunhofer approximation, a specific apodization function was applied to the received raw channel data, in real-time during image acquisition, in order to introduce a periodic oscillations pattern along the longitudinal direction of the radio frequency signal. Analytic signals were then extracted from the tagged images, and subpixel motion tracking of the intima–media complex was subsequently performed offline, by means of a previously introduced bidimensional analytic phase-based estimator. Results: The authors’ framework was applied in vivo on the common carotid artery from 20 young healthy volunteers and 6 elderly patients with high atherosclerosis risk. Cine-loops of tagged images were acquired during three cardiac cycles. Evaluated against reference trajectories manually generated by three experienced analysts, the mean absolute tracking error was 98 ± 84 μm and 55 ± 44 μm in the longitudinal and axial directions, respectively. These errors corresponded to 28% ± 23% and 13% ± 9% of the longitudinal and axial amplitude of the assessed motion, respectively. Conclusions: The proposed framework enables tagged ultrasound images of in vivo tissues to be acquired in real-time. Such unconventional beamforming strategy contributes to improve tracking accuracy and could potentially benefit to the interpretation and diagnosis of biomedical images.

  13. Environmentally driven synchronies of Mediterranean cephalopod populations

    Science.gov (United States)

    Keller, Stefanie; Quetglas, Antoni; Puerta, Patricia; Bitetto, Isabella; Casciaro, Loredana; Cuccu, Danila; Esteban, Antonio; Garcia, Cristina; Garofalo, Germana; Guijarro, Beatriz; Josephides, Marios; Jadaud, Angelique; Lefkaditou, Evgenia; Maiorano, Porzia; Manfredi, Chiara; Marceta, Bojan; Micallef, Reno; Peristeraki, Panagiota; Relini, Giulio; Sartor, Paolo; Spedicato, Maria Teresa; Tserpes, George; Hidalgo, Manuel

    2017-03-01

    The Mediterranean Sea is characterized by large scale gradients of temperature, productivity and salinity, in addition to pronounced mesoscale differences. Such a heterogeneous system is expected to shape the population dynamics of marine species. On the other hand, prevailing environmental and climatic conditions at whole basin scale may force spatially distant populations to fluctuate in synchrony. Cephalopods are excellent case studies to test these hypotheses owing to their high sensitivity to environmental conditions. Data of two cephalopod species with contrasting life histories (benthic octopus vs nectobenthic squid), obtained from scientific surveys carried out throughout the Mediterranean during the last 20 years were analyzed. The objectives of this study and the methods used to achieve them (in parentheses) were: (i) to investigate synchronies in spatially separated populations (decorrelation analysis); (ii) detect underlying common abundance trends over distant regions (dynamic factor analysis, DFA); and (iii) analyse putative influences of key environmental drivers such as productivity and sea surface temperature on the population dynamics at regional scale (general linear models, GLM). In accordance with their contrasting spatial mobility, the distance from where synchrony could no longer be detected (decorrelation scale) was higher in squid than in octopus (349 vs 217 km); for comparison, the maximum distance between locations was 2620 km. The DFA revealed a general increasing trend in the abundance of both species in most areas, which agrees with the already reported worldwide proliferation of cephalopods. DFA results also showed that population dynamics are more similar in the eastern than in the western Mediterranean basin. According to the GLM models, cephalopod populations were negatively affected by productivity, which would be explained by an increase of competition and predation by fishes. While warmer years coincided with declining octopus

  14. Neural dynamics of audiovisual synchrony and asynchrony perception in 6-month-old infants

    Directory of Open Access Journals (Sweden)

    Franziska eKopp

    2013-01-01

    Full Text Available Young infants are sensitive to multisensory temporal synchrony relations, but the neural dynamics of temporal interactions between vision and audition in infancy are not well understood. We investigated audiovisual synchrony and asynchrony perception in 6-month-old infants using event-related potentials (ERP. In a prior behavioral experiment (n = 45, infants were habituated to an audiovisual synchronous stimulus and tested for recovery of interest by presenting an asynchronous test stimulus in which the visual stream was delayed with respect to the auditory stream by 400 ms. Infants who behaviorally discriminated the change in temporal alignment were included in further analyses. In the EEG experiment (final sample: n = 15, synchronous and asynchronous stimuli (visual delay of 400 ms were presented in random order. Results show latency shifts in the auditory ERP components N1 and P2 as well as the infant ERP component Nc. Latencies in the asynchronous condition were significantly longer than in the synchronous condition. After video onset but preceding the auditory onset, amplitude modulations propagating from posterior to anterior sites and related to the Pb component of infants' ERP were observed. Results suggest temporal interactions between the two modalities. Specifically, they point to the significance of anticipatory visual motion for auditory processing, and indicate young infants’ predictive capacities for audiovisual temporal synchrony relations.

  15. Pallidal gap junctions-triggers of synchrony in Parkinson's disease?

    NARCIS (Netherlands)

    Schwab, B.C.; Heida, T.; Zhao, Y.; Gils, S.A. van; Wezel, Richard van

    2014-01-01

    Although increased synchrony of the neural activity in the basal ganglia may underlie the motor deficiencies exhibited in Parkinson's disease (PD), how this synchrony arises, propagates through the basal ganglia, and changes under dopamine replacement remains unknown. Gap junctions could play a majo

  16. Pallidal gap junctions - Triggers of synchrony in Parkinson's disease?

    NARCIS (Netherlands)

    Schwab, B.C.; Heida, Tjitske; Zhao, Yan; van Gils, Stephanus A.; van Wezel, Richard Jack Anton

    2014-01-01

    Although increased synchrony of the neural activity in the basal ganglia may underlie the motor deficiencies exhibited in Parkinson's disease (PD), how this synchrony arises, propagates through the basal ganglia, and changes under dopamine replacement remains unknown. Gap junctions could play a majo

  17. Pallidal gap junctions-triggers of synchrony in Parkinson's disease?

    NARCIS (Netherlands)

    Schwab, B.C.; Heida, T.; Zhao, Y.; Gils, S.A. van; Wezel, Richard van

    2014-01-01

    Although increased synchrony of the neural activity in the basal ganglia may underlie the motor deficiencies exhibited in Parkinson's disease (PD), how this synchrony arises, propagates through the basal ganglia, and changes under dopamine replacement remains unknown. Gap junctions could play a majo

  18. Cognitive Style and Synchrony in Measures of Anxiety.

    Science.gov (United States)

    Strohmer, Douglas C.; And Others

    1983-01-01

    Examined the extent to which a cognitive style variable, integrative complexity, was related to synchrony between behavioral and self-report measures of anxiety in counseling students (N=26). During a therapy analogue two measures of anxiety were taken. Results indicated a substantial dependence of synchrony/desynchrony on cognitive style.…

  19. Methodological Advances for Detecting Physiological Synchrony During Dyadic Interactions

    NARCIS (Netherlands)

    McAssey, M.P.; Helm, J.; Hsieh, F.; Sbarra, D.; Ferrer, E.

    2011-01-01

    A defining feature of many physiological systems is their synchrony and reciprocal influence. An important challenge, however, is how to measure such features. This paper presents two new approaches for identifying synchrony between the physiological signals of individuals in dyads. The approaches a

  20. Group Rhythmic Synchrony and Attention in Children

    Directory of Open Access Journals (Sweden)

    Alexander K Khalil

    2013-09-01

    Full Text Available Synchrony, or the coordinated processing of time, is an often-overlooked yet critical context for human interaction. This study tests the relationship between the ability to synchronize rhythmically in a group setting with the ability to attend in 102 elementary schoolchildren. Impairments in temporal processing have frequently been shown to exist in clinical populations with learning disorders, particularly those with Attention Deficit Hyperactivity Disorder (ADHD. Based on this evidence, we hypothesized that the ability to synchronize rhythmically in a group setting—an instance of the type of temporal processing necessary for successful interaction and learning—would be correlated with the ability to attend across the continuum of the population. A music class is an ideal setting for the study of interpersonal timing. In order to measure synchrony in this context, we constructed instruments that allowed the recording and measurement of individual rhythmic performance. The SWAN teacher questionnaire was used as a measurement of attentional behavior. We find that the ability to synchronize with others in a group music class can predict a child’s attentional behavior.

  1. An in vitro comparative study of intracanal fluid motion and wall shear stress induced by ultrasonic and polymer rotary finishing files in a simulated root canal model.

    Science.gov (United States)

    Koch, Jon; Borg, John; Mattson, Abby; Olsen, Kris; Bahcall, James

    2012-01-01

    Objective. This in vitro study compared the flow pattern and shear stress of an irrigant induced by ultrasonic and polymer rotary finishing file activation in an acrylic root canal model. Flow visualization analysis was performed using an acrylic canal filled with a mixture of distilled water and rheoscopic fluid. The ultrasonic and polymer rotary finishing file were separately tested in the canal and activated in a static position and in a cyclical axial motion (up and down). Particle movement in the fluid was captured using a high-speed digital camera and DaVis 7.1 software. The fluid shear stress analysis was performed using hot film anemometry. A hot-wire was placed in an acrylic root canal and the canal was filled with distilled water. The ultrasonic and polymer rotary finishing files were separately tested in a static position and in a cyclical axial motion. Positive needle irrigation was also tested separately for fluid shear stress. The induced wall shear stress was measured using LabVIEW 8.0 software.

  2. Synchrony between orientation-selective neurons is modulated during adaptation-induced plasticity in cat visual cortex

    Directory of Open Access Journals (Sweden)

    Shumikhina Svetlana

    2008-07-01

    Full Text Available Abstract Background Visual neurons respond essentially to luminance variations occurring within their receptive fields. In primary visual cortex, each neuron is a filter for stimulus features such as orientation, motion direction and velocity, with the appropriate combination of features eliciting maximal firing rate. Temporal correlation of spike trains was proposed as a potential code for linking the neuronal responses evoked by various features of a same object. In the present study, synchrony strength was measured between cells following an adaptation protocol (prolonged exposure to a non-preferred stimulus which induce plasticity of neurons' orientation preference. Results Multi-unit activity from area 17 of anesthetized adult cats was recorded. Single cells were sorted out and (1 orientation tuning curves were measured before and following 12 min adaptation and 60 min after adaptation (2 pairwise synchrony was measured by an index that was normalized in relation to the cells' firing rate. We first observed that the prolonged presentation of a non-preferred stimulus produces attractive (58% and repulsive (42% shifts of cell's tuning curves. It follows that the adaptation-induced plasticity leads to changes in preferred orientation difference, i.e. increase or decrease in tuning properties between neurons. We report here that, after adaptation, the neuron pairs that shared closer tuning properties display a significant increase of synchronization. Recovery from adaptation was accompanied by a return to the initial synchrony level. Conclusion We conclude that synchrony reflects the similarity in neurons' response properties, and varies accordingly when these properties change.

  3. Contributions of domain wall motion to complex electromechanical coefficients of 0.62Pb(Mg1∕3Nb2∕3)O3–0.38PbTiO3 crystals

    Science.gov (United States)

    Wang, Zhu; Zhang, Rui; Sun, Enwei; Cao, Wenwu

    2010-01-01

    The loss behavior of 0.62Pb(Mg1∕3Nb2∕3)O3–0.38PbTiO3 (PMN-38%PT) ferroelectric single crystal poled along [001]c was investigated. It was found that the complex electromechanical coefficients and loss factors change dramatically at the coercive field Ec around 250 V∕mm, representing the intrinsic switching barrier. Since the energy loss is related to the domain wall motion, the imaginary parts of the electromechanical coefficients can be used to study the degree of domain wall motions in relaxor-based ferroelectric single crystals. Experimental results indicate that for this system, domain wall motion contributes significantly to the imaginary parts of electromechanical coefficients. In addition, [001]c poled PMN-38%PT single crystals have much larger mechanical loss factor compared to that of conventional single crystal like LiNbO3. This phenomenon is proved to be closely related to 90° domain wall motion in this crystal system. PMID:20145700

  4. Dynamic synchrony of local cell assembly.

    Science.gov (United States)

    Sakurai, Yoshio; Takahashi, Susumu

    2008-01-01

    In the present paper, we focus on the problem of the dynamic size of a cell assembly and discuss how we can detect synchronized firing of a local cell assembly consisting of closely neighboring neurons in the working brain. A local cell assembly is difficult to detect because of the problem of spike overlapping of neighboring neurons, which cannot be overcome by ordinary spike-sorting techniques. We introduce a unique technique of spike-sorting that combines independent component analysis (ICA) and an ordinary sorting method to separate individual neighboring neurons and analyze their firing synchrony in behaving animals. One of our experiments employing this method showed that some closely neighboring neurons in the monkey prefrontal cortex have dynamic and sharp synchrony of firing reflecting local cell assemblies during working-memory processes. Another experiment showed that our other method (ICSort) of novel spike-sorting by ICA using special electrodes (dodecatrodes) can distinguish firing signals from the soma and those from the dendrites of individual neurons in behaving rats and suggests that the somatic and dendritic signals have different roles in information processing. This indicates that functional connectivity among neurons may be more dynamic and complex and spikes from the soma and dendrites of individual neurons should be considered in the investigation of the activity of local cell assemblies. We finally propose that detailed and real features of a local cell assembly consisting of closely neighboring neurons should be examined further and detection of local cell assemblies could be applied to the development of neuronal prosthetic devices, that is, brain-machine interfaces (BMIs).

  5. Sync or sink? Interpersonal synchrony impacts self-esteem

    National Research Council Canada - National Science Library

    Lumsden, Joanne; Miles, Lynden K; Macrae, C Neil

    2014-01-01

    ..., cooperation, and social-cognitive functioning. The current study sought to explore the impact of intentional synchrony versus asynchrony on an individual's self-esteem and their feelings of social connection with a partner...

  6. Eyeblink Synchrony in Multimodal Human-Android Interaction.

    Science.gov (United States)

    Tatsukawa, Kyohei; Nakano, Tamami; Ishiguro, Hiroshi; Yoshikawa, Yuichiro

    2016-12-23

    As the result of recent progress in technology of communication robot, robots are becoming an important social partner for humans. Behavioral synchrony is understood as an important factor in establishing good human-robot relationships. In this study, we hypothesized that biasing a human's attitude toward a robot changes the degree of synchrony between human and robot. We first examined whether eyeblinks were synchronized between a human and an android in face-to-face interaction and found that human listeners' eyeblinks were entrained to android speakers' eyeblinks. This eyeblink synchrony disappeared when the android speaker spoke while looking away from the human listeners but was enhanced when the human participants listened to the speaking android while touching the android's hand. These results suggest that eyeblink synchrony reflects a qualitative state in human-robot interactions.

  7. Control of spatially patterned synchrony with multisite delayed feedback

    OpenAIRE

    Hauptmann, C.; Omelchenko, O.; Popovych, O. V.; Maistrenko, Y.; Tass, P.A.

    2007-01-01

    We present an analytical study describing a method for the control of spatiotemporal patterns of synchrony in networks of coupled oscillators. Delayed feedback applied through a small number of electrodes effectively induces spatiotemporal dynamics at minimal stimulation intensities. Different arrangements of the delays cause different spatial patterns of synchrony, comparable to central pattern generators (CPGs), i.e., interacting clusters of oscillatory neurons producing patterned output, e...

  8. M型超声检测腹主动脉前后壁运动的初步研究%Primary studies of anteroposterior abdominal aortic wall motion with M-mode ultrasound

    Institute of Scientific and Technical Information of China (English)

    辛群; 蔡珠虹; 包俊敏; 梅志军; 景在平

    2011-01-01

    Objective To find out the characteristics of anteroposterior abdominal aortic wall motion and to consider the potential implications of such variations. Methods M-mode ultrasound was used to measure abdominal aortic wall motion in human (n=20) and 2 animal species [dogs (n=8), and pigs (n=5)]. Anterior wall displacement (da),posterior wall displacement (dp), and diastolic diameter (Da) were measured. The ratio of displacement to the diameter was calculated (da/Dd. and dp/Dd). Results Aortic diameter varied from to (6.34±0.84) mm (dog) to (13.76±1.11) mm (human).Anterior wall displacement was about 3 times greater than the posterior among the species studied. The ratio of wall displacement to diastolic diameter were similar for the anterior and posterior walls. Wall displacement increased linearly with the diameter. Conclusions Abdominal aortic wall dynamics are similar in humans and animals regardless of the aortic size, with more anterior than posterior wall motion. These data suggest increased .dynamic strain of the anterior wall,which may help explain why human abdominal aortic aneurysms initially develop anteriorly. Haemodynamies plays an important role in the abdominal aortic aneurysm pathogenesis.%目的:应用M型超声观测正常腹主动脉前后壁运动的特征.方法:采集健康人组、健康犬组、健康猪组腹主动脉的M型超声图像,测量动脉前壁和后壁振幅(da和dP)、舒张期动脉直径(Dd),取其平均值;并分别计算各组数值:前壁振幅/舒张期动脉直径(da/Dd),后壁振幅/舒张期动脉直径(dp/Dd).结果:三组结果显示腹主动脉前壁振幅高于后壁振幅,差异有统计学意义(P<0.01).各组中管壁振幅与管径呈正相关.da/Dd和dp/Dd组间比较,差异无统计学意义.结论:正常腹主动脉前、后壁的运动差异与腹主动脉瘤的形成有一定关系,提示血液动力学因素在腹主动脉瘤发病机制中起着重要作用.

  9. Measurements of spatial population synchrony: influence of time series transformations.

    Science.gov (United States)

    Chevalier, Mathieu; Laffaille, Pascal; Ferdy, Jean-Baptiste; Grenouillet, Gaël

    2015-09-01

    Two mechanisms have been proposed to explain spatial population synchrony: dispersal among populations, and the spatial correlation of density-independent factors (the "Moran effect"). To identify which of these two mechanisms is driving spatial population synchrony, time series transformations (TSTs) of abundance data have been used to remove the signature of one mechanism, and highlight the effect of the other. However, several issues with TSTs remain, and to date no consensus has emerged about how population time series should be handled in synchrony studies. Here, by using 3131 time series involving 34 fish species found in French rivers, we computed several metrics commonly used in synchrony studies to determine whether a large-scale climatic factor (temperature) influenced fish population dynamics at the regional scale, and to test the effect of three commonly used TSTs (detrending, prewhitening and a combination of both) on these metrics. We also tested whether the influence of TSTs on time series and population synchrony levels was related to the features of the time series using both empirical and simulated time series. For several species, and regardless of the TST used, we evidenced a Moran effect on freshwater fish populations. However, these results were globally biased downward by TSTs which reduced our ability to detect significant signals. Depending on the species and the features of the time series, we found that TSTs could lead to contradictory results, regardless of the metric considered. Finally, we suggest guidelines on how population time series should be processed in synchrony studies.

  10. Frame-differencing methods for measuring bodily synchrony in conversation.

    Science.gov (United States)

    Paxton, Alexandra; Dale, Rick

    2013-06-01

    The study of interpersonal synchrony examines how interacting individuals grow to have similar behavior, cognition, and emotion in time. Many of the established methods of analyzing interpersonal synchrony are costly and time-consuming; the study of bodily synchrony has been especially laborious, traditionally requiring researchers to hand-code movement frame by frame. Because of this, researchers have been searching for more efficient alternatives for decades. Recently, some researchers (e.g., Nagaoka & Komori (IEICE Transactions on Information and Systems, 91(6), 1634-1640, 2008); Ramseyer & Tschacher, 2008) have applied computer science and computer vision techniques to create frame-differencing methods (FDMs) to simplify analyses. In this article, we provide a detailed presentation of one such FDM, created by modifying and adding to existing FDMs. The FDM that we present requires little programming experience or specialized equipment: Only a few lines of MATLAB code are required to execute an automated analysis of interpersonal synchrony. We provide sample code and demonstrate its use with an analysis of brief, friendly conversations; using linear mixed-effects models, the measure of interpersonal synchrony was found to be significantly predicted by time lag (p < .001) and by the interaction between time lag and measures of interpersonal liking (p < .001). This pattern of results fits with existing literature on synchrony. We discuss the current limitations and future directions for FDMs, including their use as part of a larger methodology for capturing and analyzing multimodal interaction.

  11. Interhemispheric synchrony in the neonatal EEG revisited: activation synchrony index as a promising classifier.

    Science.gov (United States)

    Koolen, Ninah; Dereymaeker, Anneleen; Räsänen, Okko; Jansen, Katrien; Vervisch, Jan; Matic, Vladimir; De Vos, Maarten; Van Huffel, Sabine; Naulaers, Gunnar; Vanhatalo, Sampsa

    2014-01-01

    A key feature of normal neonatal EEG at term age is interhemispheric synchrony (IHS), which refers to the temporal co-incidence of bursting across hemispheres during trace alternant EEG activity. The assessment of IHS in both clinical and scientific work relies on visual, qualitative EEG assessment without clearly quantifiable definitions. A quantitative measure, activation synchrony index (ASI), was recently shown to perform well as compared to visual assessments. The present study was set out to test whether IHS is stable enough for clinical use, and whether it could be an objective feature of EEG normality. We analyzed 31 neonatal EEG recordings that had been clinically classified as normal (n = 14) or abnormal (n = 17) using holistic, conventional visual criteria including amplitude, focal differences, qualitative synchrony, and focal abnormalities. We selected 20-min epochs of discontinuous background pattern. ASI values were computed separately for different channel pair combinations and window lengths to define them for the optimal ASI intraindividual stability. Finally, ROC curves were computed to find trade-offs related to compromised data lengths, a common challenge in neonatal EEG studies. Using the average of four consecutive 2.5-min epochs in the centro-occipital bipolar derivations gave ASI estimates that very accurately distinguished babies clinically classified as normal vs. abnormal. It was even possible to draw a cut-off limit (ASI~3.6) which correctly classified the EEGs in 97% of all cases. Finally, we showed that compromising the length of EEG segments from 20 to 5 min leads to increased variability in ASI-based classification. Our findings support the prior literature that IHS is an important feature of normal neonatal brain function. We show that ASI may provide diagnostic value even at individual level, which strongly supports its use in prospective clinical studies on neonatal EEG as well as in the feature set of upcoming EEG classifiers.

  12. Interhemispheric synchrony in the neonatal EEG revisited: Activation Synchrony Index as a promising classifier

    Directory of Open Access Journals (Sweden)

    Ninah eKoolen

    2014-12-01

    Full Text Available A key feature of normal neonatal EEG at term age is interhemispheric synchrony (IHS, which refers to the temporal co-incidence of bursting across hemispheres during trace alternant EEG activity. The assessment of IHS in both clinical and scientific work relies on visual, qualitative EEG assessment without clearly quantifiable definitions. A quantitative measure, activation synchrony index (ASI, was recently shown to perform well as compared to visual assessments. The present study set out to test whether IHS is stable enough for clinical use, and whether it could be an objective feature of EEG normality.We analyzed 31 neonatal EEG recordings that had been clinically classified as normal (n=14 or abnormal (n=17 using holistic, conventional visual criteria including amplitude, focal differences, qualitative synchrony, and focal abnormalities. We selected 20-minute epochs of discontinuous background pattern. ASI values were computed separately for different channel pair combinations and window lengths to define the optimal ASI intraindividual stability. Finally, ROC curves were computed to find trade-offs related to compromised data lengths, a common challenge in neonatal EEG studies.Using the average of four consecutive 2.5-minute epochs in the centro-occipital bipolar derivations gave ASI estimates that very accurately distinguished babies clinically classified as normal vs. abnormal. It was even possible to draw a cut-off limit (ASI~3.6 which correctly classified the EEGs in 97% of all cases. Finally, we showed that compromising the length of EEG segments from 20 minutes to 5 minutes leads to increased variability in ASI-based classification.Our findings support the prior literature that IHS is an important feature of normal neonatal brain function. We show that ASI may provide diagnostic value even at individual level, which strongly supports its use in prospective clinical studies on neonatal EEG as well as in the feature set of upcoming EEG

  13. Rising climate variability and synchrony in North Pacific ecosystems

    Science.gov (United States)

    Black, Bryan

    2017-04-01

    Rising climate variability and synchrony in North Pacific ecosystems Evidence is growing that climate variability of the northeast Pacific Ocean has increased over the last century, culminating in such events as the record-breaking El Niño years 1983, 1998, and 2016 and the unusually persistent 2014/15 North Pacific Ocean heat wave known as "The Blob." Of particular concern is that rising variability could increase synchrony within and among North Pacific ecosystems, which could reduce the diversity of biological responses to climate (i.e. the "portfolio effect"), diminish resilience, and leave populations more prone to extirpation. To test this phenomenon, we use a network of multidecadal fish otolith growth-increment chronologies that were strongly correlated to records of winter (Jan-Mar) sea level. These biological and physical datasets spanned the California Current through the Gulf of Alaska. Synchrony was quantified as directional changes in running (31-year window) mean pairwise correlation within sea level and then within otolith time series. Synchrony in winter sea level at the nine stations with the longest records has increased by more than 40% over the 1950-2015 interval. Likewise, synchrony among the eight longest otolith chronologies has increased more than 100% over a comparable time period. These directional changes in synchrony are highly unlikely due to chance alone, as confirmed by comparing trends in observed data to those in simulated data (n = 10,000 iterations) with time series of identical number, length, and autocorrelation. Ultimately, this trend in rising synchrony may be linked to increased impacts of the El Niño Southern Oscillation (ENSO) on mid-latitude ecosystems of North America, and may therefore reflect a much broader, global-scale signature.

  14. Effect of Electric Field and Temperature on Average Structure and Domain Wall Motion in 0.93Bi0.5Na0.5TiO3-0.07BaTiO3 Ceramic

    Directory of Open Access Journals (Sweden)

    Jian Wang

    2013-01-01

    Full Text Available In situ neutron powder diffraction patterns and dielectric spectra of 0.93Bi0.5Na0.5TiO3-0.07BaTiO3 ceramic were investigated under different electrical fields and temperatures. An electric-field-induced phase transition from metrically cubic to metrically tetragonal, associated with strong domain wall motion, occurs. Such induced phase and domain wall motion are unchanged until the high-temperature phase transition occurs from metrically tetragonal to metrically cubic. All these changes are irrelevant to the observed depolarization temperature (75°C. The depolarization behaviour is thus suggested to be associated with the local structure caused by the octahedral tilt twinning disorder.

  15. Interpretation of scrape-off layer profile evolution and first-wall ion flux statistics on JET using a stochastic framework based on fillamentary motion

    Science.gov (United States)

    Walkden, N. R.; Wynn, A.; Militello, F.; Lipschultz, B.; Matthews, G.; Guillemaut, C.; Harrison, J.; Moulton, D.; Contributors, JET

    2017-08-01

    This paper presents the use of a novel modelling technique based around intermittent transport due to filament motion, to interpret experimental profile and fluctuation data in the scrape-off layer (SOL) of JET during the onset and evolution of a density profile shoulder. A baseline case is established, prior to shoulder formation, and the stochastic model is shown to be capable of simultaneously matching the time averaged profile measurement as well as the PDF shape and autocorrelation function from the ion-saturation current time series at the outer wall. Aspects of the stochastic model are then varied with the aim of producing a profile shoulder with statistical measurements consistent with experiment. This is achieved through a strong localised reduction in the density sink acting on the filaments within the model. The required reduction of the density sink occurs over a highly localised region with the timescale of the density sink increased by a factor of 25. This alone is found to be insufficient to model the expansion and flattening of the shoulder region as the density increases, which requires additional changes within the stochastic model. An example is found which includes both a reduction in the density sink and filament acceleration and provides a consistent match to the experimental data as the shoulder expands, though the uniqueness of this solution can not be guaranteed. Within the context of the stochastic model, this implies that the localised reduction in the density sink can trigger shoulder formation, but additional physics is required to explain the subsequent evolution of the profile.

  16. Interventricular delay measurement using equilibrium radionuclide angiography before resynchronization therapy should be performed outside the area of segmental wall motion abnormalities

    Energy Technology Data Exchange (ETDEWEB)

    Courtehoux, Maxime [Service EFMP CHU Trousseau, Chambray les Tours (France); Zannad, Noura; Fauchier, Laurent; Babuty, Dominique [Service Cardiologie B CHU Trousseau, Tours (France); Eder, Veronique [Service EFMP CHU Trousseau, Chambray les Tours (France); EA3852 University Francois Rabelais, Tours (France)

    2011-02-15

    The aim of this study was to demonstrate that only mechanical dyssynchrony outside the area of segmental wall motion abnormalities (WMA) can be reduced by cardiac resynchronization therapy (CRT). Included in the study were 28 consecutive patients with nonischaemic cardiomyopathy selected for CRT. Equilibrium radionuclide angiography (ERNA) was carried out before and after implantation of a multisite pacemaker. Patients were separated into two groups depending on the presence or absence of segmental WMA. A reduction in QRS duration was observed in all patients after CRT. The interventricular delay (IVD) decreased significantly after CRT only in patients without WMA (homogeneous contraction, HG group; IVD 44 {+-} 11.4 vs. 17 {+-} 3.1 , p = 0.04). In contrast, no significant decrease was observed in patients with WMA (WMA group; IVD 51 {+-} 6 vs. 38 {+-} 6 , p NS). However, when dyssynchrony was considered outside the WMA area, a significant reduction in IVD was obtained, in the same range as in the HG group (IVD 32 {+-} 3 vs. 19 {+-} 3 , p = 0.04). In 9 of 15 patients (60%) with a reduction in IVD after CRT, the left ventricle ejection fraction (LVEF) increased by about +10%. In contrast, in 13 of 13 patients (100%) with no reduction in IVD, no modification of LVEF was obtained. In the presence of segmental WMA without significant delays outside the WMA area, no reduction in IVD was observed and LVEF did not increase (IVD 34 {+-} 5 before CRT vs. 37 {+-} 7 after CRT; LVEF 19 {+-} 4% before CRT vs. 22 {+-} 3% after CRT, p NS). ERNA can be used to predict good mechanical resynchronization (decrease in IVD) in patients after pacing. IVD has to be determined excluding the area of WMA in order to select patients who will show an increase in their left ventricle function after CRT. (orig.)

  17. Influences on and measures of unintentional group synchrony

    Directory of Open Access Journals (Sweden)

    Melissa Ellamil

    2016-11-01

    Full Text Available Many instances of large-scale coordination occur in real-life social situations without the explicit awareness of the individuals involved. While the majority of research to date has examined dyadic interactions – those between two individuals – during intentional or deliberate coordination, the present review surveys the handful of recent studies investigating behavioral and physiological synchrony across groups of more than two people when coordination was not an explicit goal. Both minimal (e.g., visual information, shared location and naturalistic (e.g., choir singing part, family relationship group interactions appear to promote unintentional group synchrony although they have so far only been studied separately. State differences in unintentional group synchrony, or the relative presence of coordination in various conditions, have tended to be assessed differently, such as using correlation-type relationships, compared to its temporal dynamics, or changes over time in the degree of coordination, which appear to be best captured using phase differences. Simultaneously evaluating behavioral, physiological, and social responses as well systematically comparing different synchrony measures could further our understanding of the influences on and measures of group synchrony, allowing us to move away from studying individual persons responding to static laboratory stimuli and towards investigating collective experiences in natural, dynamic social interactions.

  18. Evaluating Interpersonal Synchrony: Wavelet Transform Toward an Unstructured Conversation.

    Science.gov (United States)

    Fujiwara, Ken; Daibo, Ikuo

    2016-01-01

    This study examined whether interpersonal synchrony could be extracted using spectrum analysis (i.e., wavelet transform) in an unstructured conversation. Sixty-two female undergraduates were randomly paired and they engaged in a 6-min unstructured conversation. Interpersonal synchrony was evaluated by calculating the cross-wavelet coherence of the time-series movement data, extracted using a video-image analysis software. The existence of synchrony was tested using a pseudo-synchrony paradigm. In addition, the frequency at which the synchrony occurred and the distribution of the relative phase was explored. The results showed that the value of cross-wavelet coherence was higher in the experimental participant pairs than in the pseudo pairs. Further, the coherence value was higher in the frequency band under 0.5 Hz. These results support the validity of evaluating interpersonal synchron Behavioral mimicry and interpersonal syyby using wavelet transform even in an unstructured conversation. However, the role of relative phase was not clear; there was no significant difference between each relative-phase region. The theoretical contribution of these findings to the area of interpersonal coordination is discussed.

  19. Plant phenological synchrony increases under rapid within-spring warming

    Science.gov (United States)

    Wang, Cong; Tang, Yanhong; Chen, Jin

    2016-05-01

    Phenological synchrony influences many ecological processes. Recent climate change has altered the synchrony of phenology, but little is known about the underlying mechanisms. Here using in situ phenological records from Europe, we found that the standard deviation (SD, as a measure of synchrony) of first leafing day (FLD) and the SD of first flowering day (FFD) among local plants were significantly smaller in the years and/or in the regions with a more rapid within-spring warming speed (WWS, the linear slope of the daily mean temperature against the days during spring, in oC/day) with correlation coefficients of ‑0.75 and ‑0.48 for FLD and ‑0.55 and ‑0.23 for FFD. We further found that the SDs of temperature sensitivity of local plants were smaller under the rapid WWS conditions with correlation coefficients of ‑0.46 and ‑0.33 for FLD and FFD respectively. This study provides the first evidence that the within-season rate of change of the temperature but not the magnitude determines plant phenological synchrony. It implies that temporally, the asymmetric seasonal climatic warming may decrease the synchrony via increasing WWS, especially in arctic regions; spatially, plants in coastal and low latitude areas with low WWS would have more diverse spring phenological traits.

  20. POPULATION SYNCHRONY WITHIN AND AMONG LEPIDOPTERA SPECIES IN RELATION TO WEATHER, PHYLOGENY, AND LARVEL PHENOLOGY

    Science.gov (United States)

    1. The population dynamics of native herbivore species in central Appalachian deciduous forests were studied by analysing patterns of synchrony among intra- and interspecific populations and weather. 2. Spatial synchrony of 10 Lepidoptera species and three weather variables (min...

  1. POPULATION SYNCHRONY WITHIN AND AMONG LEPIDOPTERA SPECIES IN RELATION TO WEATHER, PHYLOGENY, AND LARVEL PHENOLOGY

    Science.gov (United States)

    1. The population dynamics of native herbivore species in central Appalachian deciduous forests were studied by analysing patterns of synchrony among intra- and interspecific populations and weather. 2. Spatial synchrony of 10 Lepidoptera species and three weather variables (min...

  2. Movement Coordination in Psychotherapy: Synchrony of Hand Movements is Associated with Session Outcome. A Single-Case Study.

    Science.gov (United States)

    Ramseyer, Fabian; Tschacher, Wolfgang

    2016-04-01

    Previous work has shown that nonverbal behavior was associated with both session-level outcome and global outcome in psychotherapy. Nonverbal synchrony--here the coordination between patient's and psychotherapist's movement behavior--is a facet of nonverbal behavior that has recently been studied with video-based motion energy analysis (MEA). The present study aimed to replicate and extend these findings by using direct acquisition of movement data. In a single-case analysis, we monitored patient's and therapist's hand movements with a high-resolution accelerometric measurement system (Vitaport (r)). In addition to these behavioral data, both patient and therapist provided session-level ratings of various factors relevant to the psychotherapy process, which were assessed with post-session questionnaires. The patient-therapist coordination of hand movements, i.e. nonverbal synchrony, in (N = 27) sessions of this dyadic psychotherapy was positively associated with progress reported in post-session questionnaires. Sessions with good evaluations concerning the quality of therapeutic alliance were characterized by high movement coordination. Thus, accelerometric data of this therapy dyad confirmed previous findings gained through video analyses: The coordination of nonverbal behavior shown by patient and therapist was an indicator of beneficial processes occurring within sessions. This replication study showed that nonverbal synchrony embodies important aspects of the alliance. Its assessment and quantification may provide therapists important additional information on processes that usually occur outside conscious awareness, but that nevertheless influence core aspects of the therapy.

  3. The local field potential reflects surplus spike synchrony

    DEFF Research Database (Denmark)

    Denker, Michael; Roux, Sébastien; Lindén, Henrik;

    2011-01-01

    While oscillations of the local field potential (LFP) are commonly attributed to the synchronization of neuronal firing rate on the same time scale, their relationship to coincident spiking in the millisecond range is unknown. Here, we present experimental evidence to reconcile the notions...... of synchrony at the level of spiking and at the mesoscopic scale. We demonstrate that only in time intervals of significant spike synchrony that cannot be explained on the basis of firing rates, coincident spikes are better phase locked to the LFP than predicted by the locking of the individual spikes....... This effect is enhanced in periods of large LFP amplitudes. A quantitative model explains the LFP dynamics by the orchestrated spiking activity in neuronal groups that contribute the observed surplus synchrony. From the correlation analysis, we infer that neurons participate in different constellations...

  4. Pallidal gap junctions-triggers of synchrony in Parkinson's disease?

    Science.gov (United States)

    Schwab, Bettina C; Heida, Tjitske; Zhao, Yan; van Gils, Stephan A; van Wezel, Richard J A

    2014-10-01

    Although increased synchrony of the neural activity in the basal ganglia may underlie the motor deficiencies exhibited in Parkinson's disease (PD), how this synchrony arises, propagates through the basal ganglia, and changes under dopamine replacement remains unknown. Gap junctions could play a major role in modifying this synchrony, because they show functional plasticity under the influence of dopamine and after neural injury. In this study, confocal imaging was used to detect connexin-36, the major neural gap junction protein, in postmortem tissues of PD patients and control subjects in the putamen, subthalamic nucleus (STN), and external and internal globus pallidus (GPe and GPi, respectively). Moreover, we quantified how gap junctions affect synchrony in an existing computational model of the basal ganglia. We detected connexin-36 in the human putamen, GPe, and GPi, but not in the STN. Furthermore, we found that the number of connexin-36 spots in PD tissues increased by 50% in the putamen, 43% in the GPe, and 109% in the GPi compared with controls. In the computational model, gap junctions in the GPe and GPi strongly influenced synchrony. The basal ganglia became especially susceptible to synchronize with input from the cortex when gap junctions were numerous and high in conductance. In conclusion, connexin-36 expression in the human GPe and GPi suggests that gap junctional coupling exists within these nuclei. In PD, neural injury and dopamine depletion could increase this coupling. Therefore, we propose that gap junctions act as a powerful modulator of synchrony in the basal ganglia. © 2014 International Parkinson and Movement Disorder Society.

  5. Maladaptive neural synchrony in tinnitus: origin and restoration

    Directory of Open Access Journals (Sweden)

    Jos J Eggermont

    2015-02-01

    Full Text Available Tinnitus is the conscious perception of sound heard in the absence of physical sound sources external or internal to the body, reflected in aberrant neural synchrony of spontaneous or resting state brain activity. Neural synchrony is generated by the nearly simultaneous firing of individual neurons, of the synchronization of membrane potential changes in local neural groups as reflected in the local field potentials, resulting in the presence of oscillatory brain waves in the EEG. Noise-induced hearing loss, often resulting in tinnitus, causes a reorganization of the tonotopic map in auditory cortex and increased spontaneous firing rates and neural synchrony. Spontaneous brain rhythms rely on neural synchrony. Abnormal neural synchrony in tinnitus appears to be confined to specific frequency bands of brain rhythms. Increases in delta-band activity are generated by deafferented/deprived neuronal networks resulting from hearing loss. Coordinated reset (CR stimulation was developed in order to specifically counteract such abnormal neuronal synchrony by desynchronization. The goal of acoustic CR neuromodulation is to desynchronize tinnitus-related abnormal delta band oscillations. CR neuromodulation does not require permanent stimulus delivery in order to achieve long-lasting desynchronization or even a full-blown anti-kindling but may have cumulative effects, i.e. the effect of different CR epochs separated by pauses may accumulate. Unlike other approaches, acoustic CR neuromodulation does not intend to reduce tinnitus-related neuronal activity by employing lateral inhibition. The potential efficacy of acoustic CR modulation was shown in a clinical proof of concept trial, where effects achieved in 12 weeks of treatment delivered 4-6h/day persisted through a preplanned 4-week therapy pause and showed sustained long-term effects after 10 months of therapy, leading to 75% responders.

  6. Developmental changes in neuromagnetic rhythms and network synchrony in autism.

    Science.gov (United States)

    Vakorin, Vasily A; Doesburg, Sam M; Leung, Rachel C; Vogan, Vanessa M; Anagnostou, Evdokia; Taylor, Margot J

    2017-02-01

    There is gathering consensus that altered connectivity is a hallmark of the autistic brain. This includes atypical neural oscillations and their coordination across brain regions, which are understood to mediate information processing and integration. It remains unclear whether and how connectivity in various neurophysiological frequency ranges develops atypically in autism spectrum disorder (ASD). To address this in a cross-sectional sample, we recorded resting-state magnetoencephalography from 134 children and adolescents with and without ASD, and calculated resting spectral power and inter-regional synchrony (functional connectivity). Although no overall group differences were observed, significant alterations in linear and nonlinear age-related changes in resting oscillatory power and network synchrony were found. These differences were frequency- and region-specific and implicated brain systems thought to play a prominent role in ASD, such as the frontal cortex and cerebellum. We also found correlations between Autism Diagnostic Observation Schedule scores and the degree to which connectivity in cerebellar networks is "idiosyncratic" in an individual with autism. We provide the first evidence that it is the curvatures of maturational changes in neurophysiological oscillations and synchrony, rather than disturbances in a particular direction, that characterize the brain function in individuals with ASD. Moreover, the patterns of idiosyncratic distortions of network synchrony relative to the group curve are associated with behavioral symptoms of ASD. Ann Neurol 2017;81:199-211. © 2016 American Neurological Association.

  7. Early development of synchrony in cortical activations in the human.

    Science.gov (United States)

    Koolen, N; Dereymaeker, A; Räsänen, O; Jansen, K; Vervisch, J; Matic, V; Naulaers, G; De Vos, M; Van Huffel, S; Vanhatalo, S

    2016-05-13

    Early intermittent cortical activity is thought to play a crucial role in the growth of neuronal network development, and large scale brain networks are known to provide the basis for higher brain functions. Yet, the early development of the large scale synchrony in cortical activations is unknown. Here, we tested the hypothesis that the early intermittent cortical activations seen in the human scalp EEG show a clear developmental course during the last trimester of pregnancy, the period of intensive growth of cortico-cortical connections. We recorded scalp EEG from altogether 22 premature infants at post-menstrual age between 30 and 44 weeks, and the early cortical synchrony was quantified using recently introduced activation synchrony index (ASI). The developmental correlations of ASI were computed for individual EEG signals as well as anatomically and mathematically defined spatial subgroups. We report two main findings. First, we observed a robust and statistically significant increase in ASI in all cortical areas. Second, there were significant spatial gradients in the synchrony in fronto-occipital and left-to-right directions. These findings provide evidence that early cortical activity is increasingly synchronized across the neocortex. The ASI-based metrics introduced in our work allow direct translational comparison to in vivo animal models, as well as hold promise for implementation as a functional developmental biomarker in future research on human neonates.

  8. Long-range synchrony and emergence of neural reentry

    Science.gov (United States)

    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.

  9. The Spacing Principle for Unlearning Abnormal Neuronal Synchrony

    OpenAIRE

    Popovych, Oleksandr V.; Markos N Xenakis; Tass, Peter A.

    2015-01-01

    Desynchronizing stimulation techniques were developed to specifically counteract abnormal neuronal synchronization relevant to several neurological and psychiatric disorders. The goal of our approach is to achieve an anti-kindling, where the affected neural networks unlearn abnormal synaptic connectivity and, hence, abnormal neuronal synchrony, by means of desynchronizing stimulation, in particular, Coordinated Reset (CR) stimulation. As known from neuroscience, psychology and education, lear...

  10. Psychosocial effects of perceived emotional synchrony in collective gatherings.

    Science.gov (United States)

    Páez, Dario; Rimé, Bernard; Basabe, Nekane; Wlodarczyk, Anna; Zumeta, Larraitz

    2015-05-01

    In a classic theory, Durkheim (1912) predicted that because of the social sharing of emotion they generate, collective gatherings bring participants to a stage of collective effervescence in which they experience a sense of union with others and a feeling of empowerment accompanied by positive affect. This would lead them to leave the collective situation with a renewed sense of confidence in life and in social institutions. A century after Durkheim's predictions of these effects, though, they remained untested as a whole. This article reports 4 studies, 2 correlational, 1 semilongitudinal, and 1 experimental, assessing the positive effects of participation in either positively valenced (folkloric marches) or negatively valenced (protest demonstrations) collective gatherings. Results confirmed that collective gatherings consistently strengthened collective identity, identity fusion, and social integration, as well as enhancing personal and collective self-esteem and efficacy, positive affect, and positive social beliefs among participants. In line with a central tenet of the theory, emotional communion, or perceived emotional synchrony with others mediated these effects. Higher perceived emotional synchrony was associated with stronger emotional reactions, stronger social support, and higher endorsement of social beliefs and values. Participation in symbolic collective gatherings also particularly reinforced identity fusion when perceived emotional synchrony was high. The respective contributions of perceived emotional synchrony and flow, or optimal experience, were also assessed. Whereas perceived emotional synchrony emerged as strongly related to the various social outcomes, flow was observed to be related first to collective efficacy and self-esteem, and thus, to encompass mainly empowerment effects. (c) 2015 APA, all rights reserved).

  11. Sixty hertz neurostimulation amplifies subthalamic neural synchrony in Parkinson's disease.

    Directory of Open Access Journals (Sweden)

    Zack Blumenfeld

    Full Text Available High frequency subthalamic nucleus (STN deep brain stimulation (DBS improves the cardinal motor signs of Parkinson's disease (PD and attenuates STN alpha/beta band neural synchrony in a voltage-dependent manner. While there is a growing interest in the behavioral effects of lower frequency (60 Hz DBS, little is known about its effect on STN neural synchrony. Here we demonstrate for the first time that during intra-operative 60 Hz STN DBS, one or more bands of resting state neural synchrony were amplified in the STN in PD. We recorded intra-operative STN resting state local field potentials (LFPs from twenty-eight STNs in seventeen PD subjects after placement of the DBS lead (model 3389, Medtronic, Inc. before and during three randomized neurostimulation sets (130 Hz/1.35V, 130 Hz/2V, 60 Hz/2V. During 130 Hz/2V DBS, baseline (no DBS STN alpha (8-12 Hz and beta (13-35 Hz band power decreased (N=14, P < 0.001 for both, whereas during 60 Hz/2V DBS, alpha band and peak frequency power increased (P = 0.012, P = 0.007, respectively. The effect of 60 Hz/2V DBS opposed that of power-equivalent (130 Hz/1.35V DBS (alpha: P < 0.001, beta: P = 0.006. These results show that intra-operative 60 Hz STN DBS amplified whereas 130 Hz STN DBS attenuated resting state neural synchrony in PD; the effects were frequency-specific. We demonstrate that neurostimulation may be useful as a tool to selectively modulate resting state resonant bands of neural synchrony and to investigate its influence on motor and non-motor behaviors in PD and other neuropsychiatric diseases.

  12. Cilia walls influence on peristaltically induced motion of magneto-fluid through a porous medium at moderate Reynolds number: Numerical study

    Directory of Open Access Journals (Sweden)

    R.E. Abo-Elkhair

    2017-04-01

    Full Text Available This article addresses, effects of a magneto-fluid through a Darcy flow model with oscillatory wavy walled whose inner surface is ciliated. The equations that governing the flow are modeled without using any approximations. Adomian Decomposition Method (ADM is used to evaluate the solution of our system of nonlinear partial differential equations. Stream function, velocity and pressure gradient components are obtained by using the vorticity formula. The effects for our arbitrary physical parameters on flow characteristics are analyzed by plotting diagrams and discussed in details. With the help of stream lines the trapping mechanism has also been discussed. The major outcomes for the ciliated channel walls are: The axial velocity is higher without a ciliated walls than that for a ciliated walls and an opposite behaviour is shown near the ciliated channel walls. The pressure gradients in both directions are higher for a ciliated channel walls. More numbers of the trapped bolus in the absent of the eccentricity of the cilia elliptic path.

  13. Nonlinear effect of dispersal rate on spatial synchrony of predator-prey cycles.

    Science.gov (United States)

    Fox, Jeremy W; Legault, Geoffrey; Legault, Geoff; Vasseur, David A; Einarson, Jodie A

    2013-01-01

    Spatially-separated populations often exhibit positively correlated fluctuations in abundance and other population variables, a phenomenon known as spatial synchrony. Generation and maintenance of synchrony requires forces that rapidly restore synchrony in the face of desynchronizing forces such as demographic and environmental stochasticity. One such force is dispersal, which couples local populations together, thereby synchronizing them. Theory predicts that average spatial synchrony can be a nonlinear function of dispersal rate, but the form of the dispersal rate-synchrony relationship has never been quantified for any system. Theory also predicts that in the presence of demographic and environmental stochasticity, realized levels of synchrony can exhibit high variability around the average, so that ecologically-identical metapopulations might exhibit very different levels of synchrony. We quantified the dispersal rate-synchrony relationship using a model system of protist predator-prey cycles in pairs of laboratory microcosms linked by different rates of dispersal. Paired predator-prey cycles initially were anti-synchronous, and were subject to demographic stochasticity and spatially-uncorrelated temperature fluctuations, challenging the ability of dispersal to rapidly synchronize them. Mean synchrony of prey cycles was a nonlinear, saturating function of dispersal rate. Even extremely low rates of dispersal (systems are sufficient to generate and maintain synchrony of cyclic population dynamics, at least when environments are not too spatially heterogeneous.

  14. Changes in large-scale climate alter spatial synchrony of aphid pests

    Science.gov (United States)

    Sheppard, Lawrence W.; Bell, James R.; Harrington, Richard; Reuman, Daniel C.

    2016-06-01

    Spatial synchrony, the tendency of distant populations to fluctuate similarly, is a major concern in ecology. Except in special circumstances, researchers historically had difficulty identifying drivers of synchrony in field systems. Perhaps for this reason, the possibility that changes in large-scale climatic drivers may modify synchrony, thereby impacting ecosystems and human concerns, has been little examined. Here, we use wavelets to determine environmental drivers of phenological synchrony across Britain for 20 aphid species, most major crop pests. Consistently across species, changes in drivers produced large changes in aphid synchrony. Different drivers acted on different timescales: using a new wavelet analogue of the Moran theorem, we show that on long timescales (>4 years), 80% of synchrony in aphid first flights is due to synchrony in winter climate; but this explanation accounts for less short-timescale (Changes in aphid synchrony over time also differed by timescale: long-timescale synchrony fell from before 1993 to after, caused by similar changes in winter climate; whereas short-timescale synchrony increased. Shifts in winter climate are attributable to the North Atlantic Oscillation, an important climatic phenomenon, so effects described here may influence other taxa. This study documents a new way that climatic changes influence populations, through altered Moran effects.

  15. Properties of precise firing synchrony between synaptically coupled cortical interneurons depend on their mode of coupling.

    Science.gov (United States)

    Hu, Hang; Agmon, Ariel

    2015-07-01

    Precise spike synchrony has been widely reported in the central nervous system, but its functional role in encoding, processing, and transmitting information is yet unresolved. Of particular interest is firing synchrony between inhibitory cortical interneurons, thought to drive various cortical rhythms such as gamma oscillations, the hallmark of cognitive states. Precise synchrony can arise between two interneurons connected electrically, through gap junctions, chemically, through fast inhibitory synapses, or dually, through both types of connections, but the properties of synchrony generated by these different modes of connectivity have never been compared in the same data set. In the present study we recorded in vitro from 152 homotypic pairs of two major subtypes of mouse neocortical interneurons: parvalbumin-containing, fast-spiking (FS) interneurons and somatostatin-containing (SOM) interneurons. We tested firing synchrony when the two neurons were driven to fire by long, depolarizing current steps and used a novel synchrony index to quantify the strength of synchrony, its temporal precision, and its dependence on firing rate. We found that SOM-SOM synchrony, driven solely by electrical coupling, was less precise than FS-FS synchrony, driven by inhibitory or dual coupling. Unlike SOM-SOM synchrony, FS-FS synchrony was strongly firing rate dependent and was not evident at the prototypical 40-Hz gamma frequency. Computer simulations reproduced these differences in synchrony without assuming any differences in intrinsic properties, suggesting that the mode of coupling is more important than the interneuron subtype. Our results provide novel insights into the mechanisms and properties of interneuron synchrony and point out important caveats in current models of cortical oscillations.

  16. The Electromagnetic Field as a Synchrony Gauge Field

    CERN Document Server

    Bock, Robert D

    2015-01-01

    Building on our previous work, we investigate the identification of the electromagnetic field as a local gauge field of a restricted group of synchrony transformations. We begin by arguing that the inability to measure the one-way speed of light independent of a synchronization scheme necessitates that physical laws must be reformulated without distant simultaneity. As a result, we are forced to introduce a new operational definition of time which leads to a fundamental space-time invariance principle that is related to a subset of the synchrony group. We identify the gauge field associated with this new invariance principle with the electromagnetic field. Consequently, the electromagnetic field acquires a space-time interpretation, as suggested in our previous work. In addition, we investigate the static, spherically symmetric solution of the resulting field equations. Also, we discuss implications of the present work for understanding the tension between classical and quantum theory.

  17. A minimal model of self-consistent partial synchrony

    Science.gov (United States)

    Clusella, Pau; Politi, Antonio; Rosenblum, Michael

    2016-09-01

    We show that self-consistent partial synchrony in globally coupled oscillatory ensembles is a general phenomenon. We analyze in detail appearance and stability properties of this state in possibly the simplest setup of a biharmonic Kuramoto-Daido phase model as well as demonstrate the effect in limit-cycle relaxational Rayleigh oscillators. Such a regime extends the notion of splay state from a uniform distribution of phases to an oscillating one. Suitable collective observables such as the Kuramoto order parameter allow detecting the presence of an inhomogeneous distribution. The characteristic and most peculiar property of self-consistent partial synchrony is the difference between the frequency of single units and that of the macroscopic field.

  18. Emotional lability and affective synchrony in borderline personality disorder.

    Science.gov (United States)

    Schoenleber, Michelle; Berghoff, Christopher R; Tull, Matthew T; DiLillo, David; Messman-Moore, Terri; Gratz, Kim L

    2016-07-01

    Extant research on emotional lability in borderline personality disorder (BPD) has focused almost exclusively on lability of individual emotions or emotion types, with limited research considering how different types of emotions shift together over time. Thus, this study examined the temporal dynamics of emotion in BPD at the level of both individual emotions (i.e., self-conscious emotions [SCE], anger, and anxiety) and mixed emotions (i.e., synchrony between emotions). One hundred forty-four women from the community completed a diagnostic interview and laboratory study involving 5 emotion induction tasks (each of which was preceded and followed by a 5-min resting period or neutral task). State ratings of SCE, anger, and anxiety were provided at 14 time points (before and after each laboratory task and resting period). Hierarchical linear modeling results indicate that women with BPD reported greater mean levels of SCE and Anxiety (but not Anger), and greater lability of Anxiety. Women with BPD also exhibited greater variability in lability of all 3 emotions (suggestive of within-group differences in the relevance of lability to BPD). Results also revealed synchrony (i.e., positive relations) between each possible pair of emotions, regardless of BPD status. Follow-up regression analyses suggest the importance of accounting for lability when examining the role of synchrony in BPD, as the relation of SCE-Anger synchrony to BPD symptom severity was moderated by Anger and SCE lability. Specifically, synchronous changes in SCE and Anger were associated with greater BPD symptom severity when large shifts in SCE were paired with minor shifts in Anger. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  19. Bursting and Synchrony in Networks of Model Neurons

    CERN Document Server

    Geier, Christian; Elger, Christian E; Lehnertz, Klaus

    2016-01-01

    Bursting neurons are considered to be a potential cause of over-excitability and seizure susceptibility. The functional influence of these neurons in extended epileptic networks is still poorly understood. There is mounting evidence that the dynamics of neuronal networks is influenced not only by neuronal and synaptic properties but also by network topology. We investigate numerically the influence of different neuron dynamics on global synchrony in neuronal networks with complex connection topologies.

  20. Impairments of Social Motor Synchrony Evident in Autism Spectrum Disorder

    Science.gov (United States)

    Fitzpatrick, Paula; Frazier, Jean A.; Cochran, David M.; Mitchell, Teresa; Coleman, Caitlin; Schmidt, R. C.

    2016-01-01

    Social interactions typically involve movements of the body that become synchronized over time and both intentional and spontaneous interactional synchrony have been found to be an essential part of successful human interaction. However, our understanding of the importance of temporal dimensions of social motor synchrony in social dysfunction is limited. Here, we used a pendulum coordination paradigm to assess dynamic, process-oriented measures of social motor synchrony in adolescents with and without autism spectrum disorder (ASD). Our data indicate that adolescents with ASD demonstrate less synchronization in both spontaneous and intentional interpersonal coordination. Coupled oscillator modeling suggests that ASD participants assembled a synchronization dynamic with a weaker coupling strength, which corresponds to a lower sensitivity and decreased attention to the movements of the other person, but do not demonstrate evidence of a delay in information transmission. The implication of these findings for isolating an ASD-specific social synchronization deficit that could serve as an objective, bio-behavioral marker is discussed. PMID:27630599

  1. Electrical synapses and synchrony: the role of intrinsic currents.

    Science.gov (United States)

    Pfeuty, Benjamin; Mato, Germán; Golomb, David; Hansel, David

    2003-07-16

    Electrical synapses are ubiquitous in the mammalian CNS. Particularly in the neocortex, electrical synapses have been shown to connect low-threshold spiking (LTS) as well as fast spiking (FS) interneurons. Experiments have highlighted the roles of electrical synapses in the dynamics of neuronal networks. Here we investigate theoretically how intrinsic cell properties affect the synchronization of neurons interacting by electrical synapses. Numerical simulations of a network of conductance-based neurons randomly connected with electrical synapses show that potassium currents promote synchrony, whereas the persistent sodium current impedes it. Furthermore, synchrony varies with the firing rate in qualitatively different ways depending on the intrinsic currents. We also study analytically a network of quadratic integrate-and-fire neurons. We relate the stability of the asynchronous state of this network to the phase-response function (PRF), which characterizes the effect of small perturbations on the firing timing of the neurons. In particular, we show that the greater the skew of the PRF toward the first half of the period, the more stable the asynchronous state. Combining our simulations with our analytical results, we establish general rules to predict the dynamic state of large networks of neurons coupled with electrical synapses. Our work provides a natural explanation for surprising experimental observations that blocking electrical synapses may increase the synchrony of neuronal activity. It also suggests different synchronization properties for LTS and FS cells. Finally, we propose to further test our predictions in experiments using dynamic clamp techniques.

  2. Verbal Synchrony and Action Dynamics in Large Groups.

    Science.gov (United States)

    von Zimmermann, Jorina; Richardson, Daniel C

    2016-01-01

    While synchronized movement has been shown to increase liking and feelings of togetherness between people, we investigated whether collective speaking in time would change the way that larger groups played a video game together. Anthropologists have speculated that the function of interpersonal coordination in dance, chants, and singing is not just to produce warm, affiliative feelings, but also to improve group action. The group that chants and dances together hunts well together. Direct evidence for this is sparse, as research so far has mainly studied pairs, the effects of coordinated physical movement, and measured cooperation and affiliative decisions. In our experiment, large groups of people were given response handsets to play a computer game together, in which only joint coordinative efforts lead to success. Before playing, the synchrony of their verbal behavior was manipulated. After the game, we measured group members' affiliation toward their group, their performance on a memory task, and the way in which they played the group action task. We found that verbal synchrony in large groups produced affiliation, enhanced memory performance, and increased group members' coordinative efforts. Our evidence suggests that the effects of synchrony are stable across modalities, can be generalized to larger groups and have consequences for action coordination.

  3. Neural synchrony in cortical networks: history, concept and current status

    Directory of Open Access Journals (Sweden)

    Peter Uhlhaas

    2009-07-01

    Full Text Available Following the discovery of context-dependent synchronization of oscillatory neuronal responses in the visual system, the role of neural synchrony in cortical networks has been expanded to provide a general mechanism for the coordination of distributed neural activity patterns. In the current paper, we present an update of the status of this hypothesis through summarizing recent results from our laboratory that suggest important new insights regarding the mechanisms, function and relevance of this phenomenon. In the first part, we present recent results derived from animal experiments and mathematical simulations that provide novel explanations and mechanisms for zero and nero-zero phase lag synchronization. In the second part, we shall discuss the role of neural synchrony for expectancy during perceptual organization and its role in conscious experience. This will be followed by evidence that indicates that in addition to supporting conscious cognition, neural synchrony is abnormal in major brain disorders, such as schizophrenia and autism spectrum disorders. We conclude this paper with suggestions for further research as well as with critical issues that need to be addressed in future studies.

  4. Sync or sink? Interpersonal synchrony impacts self-esteem

    Directory of Open Access Journals (Sweden)

    Joanne eLumsden

    2014-09-01

    Full Text Available Synchronized behaviour has significant social influence both in terms of everyday activities (e.g., walking and talking as well as via more historical contexts (e.g., cultural rituals. Grounded in the science of coordination dynamics, previous research has revealed that interpersonal synchrony has numerous affiliative and pro-social consequences, such as enhanced rapport, cooperation, and social-cognitive functioning. The current study sought to explore the impact of intentional synchrony versus asynchrony on an individual’s self-esteem and their feelings of social connection with a partner. The results revealed that individuals felt better about themselves following a period of synchronous compared to asynchronous movement, while they also perceived a greater self-other overlap with their partner. These findings not only extend previous research on social connections following interpersonal synchrony, but also provide the first demonstration of an influence on self evaluations. Overall, it appears that moving in time with others may result in us feeling better about ourselves compared to moving to our own rhythm.

  5. Evaluation of the effects of transvenous pacing site on left ventricular function and synchrony in healthy anesthetized dogs.

    Science.gov (United States)

    Maisenbacher, Herbert W; Estrada, Amara H; Prosek, Robert; Shih, Andre C; Vangilder, James M

    2009-04-01

    OBJECTIVE-To compare the acute effects of cardiac pacing from various transvenous pacing sites on left ventricular (LV) function and synchrony in clinically normal dogs. ANIMALS-10 healthy adult mixed-breed dogs. PROCEDURES-Dogs were anesthetized, and dual-chamber transvenous biventricular pacing systems were implanted. Dogs were paced in single-chamber mode from the right atrial appendage (RAA) alone and in dual-chamber mode from the right ventricular apex (RVA), from the left ventricular free wall (LVFW), and simultaneously from the RVA and LVFW (BiV). Standard ECG and echocardiographic measurements, cardiac output measured with the lithium dilution method (LiDCO), and tissue Doppler-derived measurements of LV synchrony were obtained during each of the pacing configurations. RESULTS-Placement of the biventricular pacing systems was possible in 8 of the 10 dogs. The QRS duration was significantly different among all pacing sites, and the order of increasing duration was RAA, BiV, LVFW, and RVA. Pacing sites did not differ with respect to fractional shortening; however, pacing from the RVA resulted in a significantly lower ejection fraction than pacing from all other sites. During RVA and LVFW pacing, LiDCO was significantly lower than that at other sites; there was no significant difference between RAA and BiV pacing with respect to LiDCO. Although the degree of dyssynchrony was significantly lower during pacing from the RAA versus other ventricular pacing sites, it was not significantly different among sites. CONCLUSIONS AND CLINICAL RELEVANCE-Ventricular activation by RAA pacing provided the best LV function and synchrony. Pacing from the RVA worsened LV function, and although pacing from the LVFW improved it, BiV pacing may provide additional improvement.

  6. Maternal emotion dysregulation is related to heightened mother-infant synchrony of facial affect.

    Science.gov (United States)

    Lotzin, Annett; Schiborr, Julia; Barkmann, Claus; Romer, Georg; Ramsauer, Brigitte

    2016-05-01

    A heightened synchrony between the mother's and infant's facial affect predicts adverse infant development. We know that maternal psychopathology is related to mother-infant facial affect synchrony, but it is unclear how maternal psychopathology is transmitted to mother-infant synchrony. One pathway might be maternal emotion dysregulation. We examined (a) whether maternal emotion dysregulation is positively related to facial affect synchrony and (b) whether maternal emotion dysregulation mediates the effect of maternal psychopathology on mother-infant facial affect synchrony. We observed 68 mothers with mood disorders and their 4- to 9-month-old infants in the Still-Face paradigm during two play interactions. The mother's and infant's facial affect were rated from high negative to high positive, and the degree of synchrony between the mother's and infant's facial affect was computed with a time-series analysis. Emotion dysregulation was measured with the Difficulties in Emotion Regulation Scale, and psychopathology was assessed with the Symptom Checklist-90-Revised. Higher maternal emotion dysregulation was significantly associated with higher facial affect synchrony; emotion dysregulation fully mediated the effect of maternal psychopathology on facial affect synchrony. Our findings demonstrate that maternal emotion dysregulation rather than maternal psychopathology per se places mothers and infants at risk for heightened facial affect synchrony.

  7. The generation of antiphase oscillations and synchrony by a rebound-based vertebrate central pattern generator.

    Science.gov (United States)

    Li, Wen-Chang; Merrison-Hort, Robert; Zhang, Hong-Yan; Borisyuk, Roman

    2014-04-23

    Many neural circuits are capable of generating multiple stereotyped outputs after different sensory inputs or neuromodulation. We have previously identified the central pattern generator (CPG) for Xenopus tadpole swimming that involves antiphase oscillations of activity between the left and right sides. Here we analyze the cellular basis for spontaneous left-right motor synchrony characterized by simultaneous bursting on both sides at twice the swimming frequency. Spontaneous synchrony bouts are rare in most tadpoles, and they instantly emerge from and switch back to swimming, most frequently within the first second after skin stimulation. Analyses show that only neurons that are active during swimming fire action potentials in synchrony, suggesting both output patterns derive from the same neural circuit. The firing of excitatory descending interneurons (dINs) leads that of other types of neurons in synchrony as it does in swimming. During synchrony, the time window between phasic excitation and inhibition is 7.9 ± 1 ms, shorter than that in swimming (41 ± 2.3 ms). The occasional, extra midcycle firing of dINs during swimming may initiate synchrony, and mismatches of timing in the left and right activity can switch synchrony back to swimming. Computer modeling supports these findings by showing that the same neural network, in which reciprocal inhibition mediates rebound firing, can generate both swimming and synchrony without circuit reconfiguration. Modeling also shows that lengthening the time window between phasic excitation and inhibition by increasing dIN synaptic/conduction delay can improve the stability of synchrony.

  8. The Effect of Different Phases of Synchrony on Pain Threshold in a Drumming Task

    Directory of Open Access Journals (Sweden)

    Philip Sullivan

    2017-06-01

    Full Text Available Behavioral synchrony has been linked to endorphin activity (Cohen et al., 2010; Sullivan and Rickers, 2013; Sullivan et al., 2014; Tarr et al., 2015, 2016; Weinstein et al., 2016. This has been called the synchrony effect. Synchrony has two dominant phases of movement; in-phase and anti-phase. The majority of research investigating synchrony’s effect on endorphin activity has focused on in-phase synchrony following vigorous activities. The only research to investigate the effects of anti-phase synchrony on endorphin activity found that anti-phase synchronized rowing did not produce the synchrony effect (Sullivan et al., 2014. Anti-phase synchrony, however, is counter-intuitive to the sport of rowing and may have interfered with the synchrony effect. This study investigated the effect of anti-phase synchrony on endorphin activity in a different task (i.e., drumming. University students (n = 30 were asked to drum solo and in in-phase and anti-phase pairs for 3 min. Pain threshold was assessed as an indirect indicator of endorphin activity prior to and following the task. Although the in-phase synchrony effect was not found, a repeated measures ANOVA found that there was a significant difference in pain threshold change among the three conditions [F(2,24 = 4.10, = 0.255, p < 0.05. Post hoc t-tests showed that the anti-phase condition had a significantly greater pain threshold change than both the solo and in-phase conditions at p < 0.05. This is the first time that anti-phase synchrony has been shown to produce the synchrony effect. Because anti-phase drumming may have required more attention between partners than in-phase synchrony, it may have affected self-other merging (Tarr et al., 2014. These results support Tarr et al.’s (2014 model that multiple mechanisms account for the effect of synchrony on pain threshold, and suggest that different characteristics of the activity may influence the synchrony effect.

  9. Gaze Synchrony between Mothers with Mood Disorders and Their Infants: Maternal Emotion Dysregulation Matters.

    Directory of Open Access Journals (Sweden)

    Annett Lotzin

    Full Text Available A lowered and heightened synchrony between the mother's and infant's nonverbal behavior predicts adverse infant development. We know that maternal depressive symptoms predict lowered and heightened mother-infant gaze synchrony, but it is unclear whether maternal emotion dysregulation is related to mother-infant gaze synchrony. This cross-sectional study examined whether maternal emotion dysregulation in mothers with mood disorders is significantly related to mother-infant gaze synchrony. We also tested whether maternal emotion dysregulation is relatively more important than maternal depressive symptoms in predicting mother-infant gaze synchrony, and whether maternal emotion dysregulation mediates the relation between maternal depressive symptoms and mother-infant gaze synchrony. We observed 68 mothers and their 4- to 9-month-old infants in the Still-Face paradigm during two play interactions, before and after social stress was induced. The mothers' and infants' gaze behaviors were coded using microanalysis with the Maternal Regulatory Scoring System and Infant Regulatory Scoring System, respectively. The degree of mother-infant gaze synchrony was computed using time-series analysis. Maternal emotion dysregulation was measured by the Difficulties in Emotion Regulation Scale; depressive symptoms were assessed using the Beck Depression Inventory. Greater maternal emotion dysregulation was significantly related to heightened mother-infant gaze synchrony. The overall effect of maternal emotion dysregulation on mother-infant gaze synchrony was relatively more important than the effect of maternal depressive symptoms in the five tested models. Maternal emotion dysregulation fully mediated the relation between maternal depressive symptoms and mother-infant gaze synchrony. Our findings suggest that the effect of the mother's depressive symptoms on the mother-infant gaze synchrony may be mediated by the mother's emotion dysregulation.

  10. Gaze Synchrony between Mothers with Mood Disorders and Their Infants: Maternal Emotion Dysregulation Matters.

    Science.gov (United States)

    Lotzin, Annett; Romer, Georg; Schiborr, Julia; Noga, Berit; Schulte-Markwort, Michael; Ramsauer, Brigitte

    2015-01-01

    A lowered and heightened synchrony between the mother's and infant's nonverbal behavior predicts adverse infant development. We know that maternal depressive symptoms predict lowered and heightened mother-infant gaze synchrony, but it is unclear whether maternal emotion dysregulation is related to mother-infant gaze synchrony. This cross-sectional study examined whether maternal emotion dysregulation in mothers with mood disorders is significantly related to mother-infant gaze synchrony. We also tested whether maternal emotion dysregulation is relatively more important than maternal depressive symptoms in predicting mother-infant gaze synchrony, and whether maternal emotion dysregulation mediates the relation between maternal depressive symptoms and mother-infant gaze synchrony. We observed 68 mothers and their 4- to 9-month-old infants in the Still-Face paradigm during two play interactions, before and after social stress was induced. The mothers' and infants' gaze behaviors were coded using microanalysis with the Maternal Regulatory Scoring System and Infant Regulatory Scoring System, respectively. The degree of mother-infant gaze synchrony was computed using time-series analysis. Maternal emotion dysregulation was measured by the Difficulties in Emotion Regulation Scale; depressive symptoms were assessed using the Beck Depression Inventory. Greater maternal emotion dysregulation was significantly related to heightened mother-infant gaze synchrony. The overall effect of maternal emotion dysregulation on mother-infant gaze synchrony was relatively more important than the effect of maternal depressive symptoms in the five tested models. Maternal emotion dysregulation fully mediated the relation between maternal depressive symptoms and mother-infant gaze synchrony. Our findings suggest that the effect of the mother's depressive symptoms on the mother-infant gaze synchrony may be mediated by the mother's emotion dysregulation.

  11. A neuropeptide speeds circadian entrainment by reducing intercellular synchrony.

    Science.gov (United States)

    An, Sungwon; Harang, Rich; Meeker, Kirsten; Granados-Fuentes, Daniel; Tsai, Connie A; Mazuski, Cristina; Kim, Jihee; Doyle, Francis J; Petzold, Linda R; Herzog, Erik D

    2013-11-12

    Shift work or transmeridian travel can desynchronize the body's circadian rhythms from local light-dark cycles. The mammalian suprachiasmatic nucleus (SCN) generates and entrains daily rhythms in physiology and behavior. Paradoxically, we found that vasoactive intestinal polypeptide (VIP), a neuropeptide implicated in synchrony among SCN cells, can also desynchronize them. The degree and duration of desynchronization among SCN neurons depended on both the phase and the dose of VIP. A model of the SCN consisting of coupled stochastic cells predicted both the phase- and the dose-dependent response to VIP and that the transient phase desynchronization, or "phase tumbling", could arise from intrinsic, stochastic noise in small populations of key molecules (notably, Period mRNA near its daily minimum). The model also predicted that phase tumbling following brief VIP treatment would accelerate entrainment to shifted environmental cycles. We tested this using a prepulse of VIP during the day before a shift in either a light cycle in vivo or a temperature cycle in vitro. Although VIP during the day does not shift circadian rhythms, the VIP pretreatment approximately halved the time required for mice to reentrain to an 8-h shifted light schedule and for SCN cultures to reentrain to a 10-h shifted temperature cycle. We conclude that VIP below 100 nM synchronizes SCN cells and above 100 nM reduces synchrony in the SCN. We show that exploiting these mechanisms that transiently reduce cellular synchrony before a large shift in the schedule of daily environmental cues has the potential to reduce jet lag.

  12. Statistical detection of EEG synchrony using empirical bayesian inference.

    Directory of Open Access Journals (Sweden)

    Archana K Singh

    Full Text Available There is growing interest in understanding how the brain utilizes synchronized oscillatory activity to integrate information across functionally connected regions. Computing phase-locking values (PLV between EEG signals is a popular method for quantifying such synchronizations and elucidating their role in cognitive tasks. However, high-dimensionality in PLV data incurs a serious multiple testing problem. Standard multiple testing methods in neuroimaging research (e.g., false discovery rate, FDR suffer severe loss of power, because they fail to exploit complex dependence structure between hypotheses that vary in spectral, temporal and spatial dimension. Previously, we showed that a hierarchical FDR and optimal discovery procedures could be effectively applied for PLV analysis to provide better power than FDR. In this article, we revisit the multiple comparison problem from a new Empirical Bayes perspective and propose the application of the local FDR method (locFDR; Efron, 2001 for PLV synchrony analysis to compute FDR as a posterior probability that an observed statistic belongs to a null hypothesis. We demonstrate the application of Efron's Empirical Bayes approach for PLV synchrony analysis for the first time. We use simulations to validate the specificity and sensitivity of locFDR and a real EEG dataset from a visual search study for experimental validation. We also compare locFDR with hierarchical FDR and optimal discovery procedures in both simulation and experimental analyses. Our simulation results showed that the locFDR can effectively control false positives without compromising on the power of PLV synchrony inference. Our results from the application locFDR on experiment data detected more significant discoveries than our previously proposed methods whereas the standard FDR method failed to detect any significant discoveries.

  13. Statistical detection of EEG synchrony using empirical bayesian inference.

    Science.gov (United States)

    Singh, Archana K; Asoh, Hideki; Takeda, Yuji; Phillips, Steven

    2015-01-01

    There is growing interest in understanding how the brain utilizes synchronized oscillatory activity to integrate information across functionally connected regions. Computing phase-locking values (PLV) between EEG signals is a popular method for quantifying such synchronizations and elucidating their role in cognitive tasks. However, high-dimensionality in PLV data incurs a serious multiple testing problem. Standard multiple testing methods in neuroimaging research (e.g., false discovery rate, FDR) suffer severe loss of power, because they fail to exploit complex dependence structure between hypotheses that vary in spectral, temporal and spatial dimension. Previously, we showed that a hierarchical FDR and optimal discovery procedures could be effectively applied for PLV analysis to provide better power than FDR. In this article, we revisit the multiple comparison problem from a new Empirical Bayes perspective and propose the application of the local FDR method (locFDR; Efron, 2001) for PLV synchrony analysis to compute FDR as a posterior probability that an observed statistic belongs to a null hypothesis. We demonstrate the application of Efron's Empirical Bayes approach for PLV synchrony analysis for the first time. We use simulations to validate the specificity and sensitivity of locFDR and a real EEG dataset from a visual search study for experimental validation. We also compare locFDR with hierarchical FDR and optimal discovery procedures in both simulation and experimental analyses. Our simulation results showed that the locFDR can effectively control false positives without compromising on the power of PLV synchrony inference. Our results from the application locFDR on experiment data detected more significant discoveries than our previously proposed methods whereas the standard FDR method failed to detect any significant discoveries.

  14. Measurement of phase synchrony of coupled segmentation clocks.

    Science.gov (United States)

    Alam, Md Jahoor; Bhayana, Latika; Devi, Gurumayum Reenaroy; Singh, Heisnam Dinachandra; Singh, R K Brojen; Sharma, B Indrajit

    2011-10-01

    The temporal behavior of segmentation clock oscillations shows phase synchrony via mean field like coupling of delta protein restricting to nearest neighbors only, in a configuration of cells arranged in a regular three dimensional array. We found the increase of amplitudes of oscillating dynamical variables of the cells as the activation rate of delta-notch signaling is increased, however, the frequencies of oscillations are decreased correspondingly. Our results show the phase transition from desynchronized to synchronized behavior by identifying three regimes, namely, desynchronized, transition and synchronized regimes supported by various qualitative and quantitative measurements.

  15. Nonverbal Synchrony in Psychotherapy: Coordinated Body Movement Reflects Relationship Quality and Outcome

    Science.gov (United States)

    Ramseyer, Fabian; Tschacher, Wolfgang

    2011-01-01

    Objective: The authors quantified nonverbal synchrony--the coordination of patient's and therapist's movement--in a random sample of same-sex psychotherapy dyads. The authors contrasted nonverbal synchrony in these dyads with a control condition and assessed its association with session-level and overall psychotherapy outcome. Method: Using an…

  16. Moderators of the synchrony of change between decreasing depression severity and disability

    NARCIS (Netherlands)

    Verboom, C. E.; Ormel, J.; Nolen, W. A.; Penninx, B. W. J. H.; Sijtsema, J. J.

    2012-01-01

    Verboom CE, Ormel J, Nolen WA, Penninx BWJH, Sijtsema JJ. Moderators of the synchrony of change between decreasing depression severity and disability. Objective: To identify moderators of synchrony of change between depression severity and disability. Method: From a large cohort study with 2 years o

  17. Moderators of the synchrony of change between decreasing depression severity and disability

    NARCIS (Netherlands)

    Verboom, C. E.; Ormel, J.; Nolen, W. A.; Penninx, B. W. J. H.; Sijtsema, J. J.

    2012-01-01

    Verboom CE, Ormel J, Nolen WA, Penninx BWJH, Sijtsema JJ. Moderators of the synchrony of change between decreasing depression severity and disability. Objective: To identify moderators of synchrony of change between depression severity and disability. Method: From a large cohort study with 2 years o

  18. One in the Dance: Musical Correlates of Group Synchrony in a Real-World Club Environment

    Science.gov (United States)

    Ellamil, Melissa; Berson, Joshua; Wong, Jen; Buckley, Louis; Margulies, Daniel S.

    2016-01-01

    Previous research on interpersonal synchrony has mainly investigated small groups in isolated laboratory settings, which may not fully reflect the complex and dynamic interactions of real-life social situations. The present study expands on this by examining group synchrony across a large number of individuals in a naturalistic environment. Smartphone acceleration measures were recorded from participants during a music set in a dance club and assessed to identify how group movement synchrony covaried with various features of the music. In an evaluation of different preprocessing and analysis methods, giving more weight to front-back movement provided the most sensitive and reliable measure of group synchrony. During the club music set, group synchrony of torso movement was most strongly associated with pulsations that approximate walking rhythm (100–150 beats per minute). Songs with higher real-world play counts were also correlated with greater group synchrony. Group synchrony thus appears to be constrained by familiarity of the movement (walking action and rhythm) and of the music (song popularity). These findings from a real-world, large-scale social and musical setting can guide the development of methods for capturing and examining collective experiences in the laboratory and for effectively linking them to synchrony across people in daily life. PMID:27764167

  19. Analyzing the Effects of Gap Junction Blockade on Neural Synchrony via a Motoneuron Network Computational Model

    Directory of Open Access Journals (Sweden)

    Heraldo Memelli

    2012-01-01

    Full Text Available In specific regions of the central nervous system (CNS, gap junctions have been shown to participate in neuronal synchrony. Amongst the CNS regions identified, some populations of brainstem motoneurons are known to be coupled by gap junctions. The application of various gap junction blockers to these motoneuron populations, however, has led to mixed results regarding their synchronous firing behavior, with some studies reporting a decrease in synchrony while others surprisingly find an increase in synchrony. To address this discrepancy, we employ a neuronal network model of Hodgkin-Huxley-style motoneurons connected by gap junctions. Using this model, we implement a series of simulations and rigorously analyze their outcome, including the calculation of a measure of neuronal synchrony. Our simulations demonstrate that under specific conditions, uncoupling of gap junctions is capable of producing either a decrease or an increase in neuronal synchrony. Subsequently, these simulations provide mechanistic insight into these different outcomes.

  20. Opportunities to enhance performance and efficiency through nutrient synchrony in forage-fed ruminants.

    Science.gov (United States)

    Hersom, M J

    2008-04-01

    Increasingly, the need for optimized nutrient utilization to address increasing production costs and environmental considerations will necessitate opportunities to improve nutrient synchrony. Historically, attempts at synchronizing nutrient supply in ruminants, particularly in cattle consuming high-forage diets, have met with variable results. The success of nutrient synchrony has been measured primarily in ruminants by increases in microbial yield, microbial efficiency, nutrient utilization, and to a lesser extent, animal performance. Successful synchrony of nutrient supply to cattle consuming forage-based diets faces several challenges. From a feed supply aspect, the challenges to nutrient synchrony include accurately measuring forage intake and consumed forage chemical composition. The issue of forage intake and chemical composition is perhaps the most daunting for producers grazing cattle. Indeed, for forage-fed cattle, the availability of forage protein and carbohydrate can be the most asynchronous aspect of the diet. In most grazed forages, digestion rates of the carbohydrate fractions are much slower than that of the corresponding protein fractions. Additionally, the forage-supplement interaction exerts a large impact on the synchrony of nutrients. The supplemental feedstuffs compose the component of the nutrient synchrony scenario that is most often manipulated to influence synchrony. The supplement type (e.g., starch vs. fiber, dry vs. liquid), nutrient profile, and degradation rates are often prime considerations associated with nutrient synchrony on high forage diets. Other considerations that warrant attention include temporal intake patterns of the forage and supplement, increased use and types of coproduct supplements, and an assessment of the success of nutrient synchrony. Synchronization of nutrient utilization by forage-fed ruminants has and will continue to encounter challenges for successful outcomes. Ultimately it is the improvement in animal

  1. You are in sync with me: neural correlates of interpersonal synchrony with a partner.

    Science.gov (United States)

    Cacioppo, S; Zhou, H; Monteleone, G; Majka, E A; Quinn, K A; Ball, A B; Norman, G J; Semin, G R; Cacioppo, J T

    2014-09-26

    Interpersonal synchrony is characterized by a temporary alignment of periodic behaviors with another person. This process requires that at least one of the two individuals monitors and adjusts his/her movements to maintain alignment with the other individual (the referent). Interestingly, recent research on interpersonal synchrony has found that people who are motivated to befriend an unfamiliar social referent tend to automatically synchronize with their social referents, raising the possibility that synchrony may be employed as an affiliation tool. It is unknown, however, whether the opposite is true; that is, whether the person serving as the referent of interpersonal synchrony perceives synchrony with his/her partner or experiences affiliative feelings toward the partner. To address this question, we performed a series of studies on interpersonal synchrony with a total of 100 participants. In all studies, participants served as the referent with no requirement to monitor or align their behavior with their partners. Unbeknown to the participants, the timings of their "partner's" movements were actually determined by a computer program based on the participant's (i.e., referent's) behavior. Overall, our behavioral results showed that the referent of a synchrony task expressed greater perceived synchrony and greater social affiliation toward a synchronous partner (i.e., one displaying low mean asynchrony and/or a narrow asynchrony range) than with an asynchronous partner (i.e., one displaying high mean asynchrony and/or high asynchrony range). Our neuroimaging study extended these results by demonstrating involvement of brain areas implicated in social cognition, embodied cognition, self-other expansion, and action observation as correlates of interpersonal synchrony (vs. asynchrony). These findings have practical implications for social interaction and theoretical implications for understanding interpersonal synchrony and social coordination.

  2. The spacing principle for unlearning abnormal neuronal synchrony.

    Science.gov (United States)

    Popovych, Oleksandr V; Xenakis, Markos N; Tass, Peter A

    2015-01-01

    Desynchronizing stimulation techniques were developed to specifically counteract abnormal neuronal synchronization relevant to several neurological and psychiatric disorders. The goal of our approach is to achieve an anti-kindling, where the affected neural networks unlearn abnormal synaptic connectivity and, hence, abnormal neuronal synchrony, by means of desynchronizing stimulation, in particular, Coordinated Reset (CR) stimulation. As known from neuroscience, psychology and education, learning effects can be enhanced by means of the spacing principle, i.e. by delivering repeated stimuli spaced by pauses as opposed to delivering a massed stimulus (in a single long stimulation session). To illustrate that the spacing principle may boost the anti-kindling effect of CR neuromodulation, in this computational study we carry this approach to extremes. To this end, we deliver spaced CR neuromodulation at particularly weak intensities which render permanently delivered CR neuromodulation ineffective. Intriguingly, spaced CR neuromodulation at these particularly weak intensities effectively induces an anti-kindling. In fact, the spacing principle enables the neuronal population to successively hop from one attractor to another one, finally approaching attractors characterized by down-regulated synaptic connectivity and synchrony. Our computational results might open up novel opportunities to effectively induce sustained desynchronization at particularly weak stimulation intensities, thereby avoiding side effects, e.g., in the case of deep brain stimulation.

  3. Local variations in spatial synchrony of influenza epidemics.

    Directory of Open Access Journals (Sweden)

    James H Stark

    Full Text Available BACKGROUND: Understanding the mechanism of influenza spread across multiple geographic scales is not complete. While the mechanism of dissemination across regions and states of the United States has been described, understanding the determinants of dissemination between counties has not been elucidated. The paucity of high resolution spatial-temporal influenza incidence data to evaluate disease structure is often not available. METHODOLOGY AND FINDINGS: We report on the underlying relationship between the spread of influenza and human movement between counties of one state. Significant synchrony in the timing of epidemics exists across the entire state and decay with distance (regional correlation=62%. Synchrony as a function of population size display evidence of hierarchical spread with more synchronized epidemics occurring among the most populated counties. A gravity model describing movement between two populations is a stronger predictor of influenza spread than adult movement to and from workplaces suggesting that non-routine and leisure travel drive local epidemics. CONCLUSIONS: These findings highlight the complex nature of influenza spread across multiple geographic scales.

  4. Meaningful auditory information enhances perception of visual biological motion.

    Science.gov (United States)

    Arrighi, Roberto; Marini, Francesco; Burr, David

    2009-04-30

    Robust perception requires efficient integration of information from our various senses. Much recent electrophysiology points to neural areas responsive to multisensory stimulation, particularly audiovisual stimulation. However, psychophysical evidence for functional integration of audiovisual motion has been ambiguous. In this study we measure perception of an audiovisual form of biological motion, tap dancing. The results show that the audio tap information interacts with visual motion information, but only when in synchrony, demonstrating a functional combination of audiovisual information in a natural task. The advantage of multimodal combination was better than the optimal maximum likelihood prediction.

  5. Field-driven domain wall motion under a bias current in the creep and flow regimes in Pt/[CoSiB/Pt]N nanowires.

    Science.gov (United States)

    Choi, Y H; Yoshimura, Y; Kim, K-J; Lee, K; Kim, T W; Ono, T; You, C-Y; Jung, M H

    2016-03-31

    The dynamics of magnetic domain wall (DW) in perpendicular magnetic anisotropy Pt/[CoSiB/Pt]N nanowires was studied by measuring the DW velocity under a magnetic field (H) and an electric current (J) in two extreme regimes of DW creep and flow. Two important findings are addressed. One is that the field-driven DW velocity increases with increasing N in the flow regime, whereas the trend is inverted in the creep regime. The other is that the sign of spin current-induced effective field is gradually reversed with increasing N in both DW creep and flow regimes. To reveal the underlying mechanism of new findings, we performed further experiment and micromagnetic simulation, from which we found that the observed phenomena can be explained by the combined effect of the DW anisotropy, Dzyaloshinskii-Moriya interaction, spin-Hall effect, and spin-transfer torques. Our results shed light on the mechanism of DW dynamics in novel amorphous PMA nanowires, so that this work may open a path to utilize the amorphous PMA in emerging DW-based spintronic devices.

  6. Avaliação quantitativa da movimentação parietal regional do ventrículo esquerdo na endomiocardiofibrose Quantitative assessment of left ventricular regional wall motion in endomyocardial fibrosis

    Directory of Open Access Journals (Sweden)

    Charles Mady

    2005-03-01

    motion in patients with endomyocardial fibrosis (EMF. METHODS: The study comprised 88 patients, 59 of the female sex, with a mean age of 39±13 years (range, 9 to 65 and with echocardiographic and angiographic evidence of left ventricular EMF. The intensity of fibrous tissue buildup on contrast cineventriculography was classified as mild, moderate, or severe. The overall left ventricular ejection fraction (LVEF was determined by using the area-length method on ventriculography. The motion was measured in 100 equidistant chords perpendicular to the centerline drawn in the middle of the final diastolic and systolic contours and normalized to cardiac size. Five left ventricular segments were analyzed: A - apical; AL - anterolateral; AB - anterobasal; IA - inferoapical; IB - inferobasal. Abnormality was expressed in units of standard deviation of the mean motion in a normal population of reference, comprised of 103 patients with normal LV according to clinical and electrocardiographic data, and angiographic standards. RESULTS: Mean LVEF was 0.47±0.12. Fibrous tissue buildup in the left ventricle was mild in 12 patients, moderate in 40, and severe in 36. The regions with the poorest ventricular wall motion were A (-1.4±1.6 standard deviation/chords and IA (-1.6±1.8 standard deviation/chords compared with that in AB (-0.3±1.9 standard deviation/chords, AL (-0.5±1.8 standard deviation/chords and IB (-0.9±1.3 standard deviation/chords. No relation was observed between the intensity of fibrous tissue buildup and regional ventricular wall motion. CONCLUSION: A change in LV regional wall motion exists in EMF, and it is independent of the intensity of fibrous tissue buildup qualitatively assessed. Nonuniform involvement of the LV should be considered when planning surgery for this disease.

  7. Rate-synchrony relationship between input and output of spike trains in neuronal networks

    Science.gov (United States)

    Wang, Sentao; Zhou, Changsong

    2010-01-01

    Neuronal networks interact via spike trains. How the spike trains are transformed by neuronal networks is critical for understanding the underlying mechanism of information processing in the nervous system. Both the rate and synchrony of the spikes can affect the transmission, while the relationship between them has not been fully understood. Here we investigate the mapping between input and output spike trains of a neuronal network in terms of firing rate and synchrony. With large enough input rate, the working mode of the neurons is gradually changed from temporal integrators into coincidence detectors when the synchrony degree of input spike trains increases. Since the membrane potentials of the neurons can be depolarized to near the firing threshold by uncorrelated input spikes, small input synchrony can cause great output synchrony. On the other hand, the synchrony in the output may be reduced when the input rate is too small. The case of the feedforward network can be regarded as iterative process of such an input-output relationship. The activity in deep layers of the feedforward network is in an all-or-none manner depending on the input rate and synchrony.

  8. Crowd Synchrony and Quorum Sensing in Delay-Coupled Lasers

    Science.gov (United States)

    Zamora-Munt, Jordi; Masoller, C.; Garcia-Ojalvo, Jordi; Roy, Rajarshi

    2010-12-01

    Crowd synchrony and quorum sensing arise when a large number of dynamical elements communicate with each other via a common information pool. Previous evidence has shown that this type of coupling leads to synchronization, when coupling is instantaneous and the number of coupled elements is large enough. Here we consider a situation in which the transmission of information between the system components and the coupling pool is not instantaneous. To that end, we model a system of semiconductor lasers optically coupled to a central laser with a delay. Our results show that, even though the lasers are nonidentical due to their distinct optical frequencies, zero-lag synchronization arises. By changing a system parameter, we can switch between two different types of synchronization transition. The dependence of the transition with respect to the delay-coupling parameters is studied.

  9. Timing intervals using population synchrony and spike timing dependent plasticity

    Directory of Open Access Journals (Sweden)

    Wei Xu

    2016-12-01

    Full Text Available We present a computational model by which ensembles of regularly spiking neurons can encode different time intervals through synchronous firing. We show that a neuron responding to a large population of convergent inputs has the potential to learn to produce an appropriately-timed output via spike-time dependent plasticity. We explain why temporal variability of this population synchrony increases with increasing time intervals. We also show that the scalar property of timing and its violation at short intervals can be explained by the spike-wise accumulation of jitter in the inter-spike intervals of timing neurons. We explore how the challenge of encoding longer time intervals can be overcome and conclude that this may involve a switch to a different population of neurons with lower firing rate, with the added effect of producing an earlier bias in response. Experimental data on human timing performance show features in agreement with the model’s output.

  10. SPIKY: A graphical user interface for monitoring spike train synchrony

    CERN Document Server

    Bozanic, Nebojsa

    2014-01-01

    Techniques for recording large-scale neuronal spiking activity are developing very fast. This leads to an increasing demand for algorithms capable of analyzing large amounts of experimental spike train data. One of the most crucial and demanding tasks is the identification of similarity patterns with a very high temporal resolution and across different spatial scales. To address this task, in recent years three time-resolved measures of spike train synchrony have been proposed, the ISI-distance, the SPIKE-distance, and event synchronization. The Matlab source codes for calculating and visualizing these measures have been made publicly available. However, due to the many different possible representations of the results the use of these codes is rather complicated and their application requires some basic knowledge of Matlab. Thus it became desirable to provide a more user-friendly and interactive interface. Here we address this need and present SPIKY, a graphical user interface which facilitates the applicati...

  11. Dispersal and noise: Various modes of synchrony in ecological oscillators

    KAUST Repository

    Bressloff, Paul C.

    2012-10-21

    We use the theory of noise-induced phase synchronization to analyze the effects of dispersal on the synchronization of a pair of predator-prey systems within a fluctuating environment (Moran effect). Assuming that each isolated local population acts as a limit cycle oscillator in the deterministic limit, we use phase reduction and averaging methods to derive a Fokker-Planck equation describing the evolution of the probability density for pairwise phase differences between the oscillators. In the case of common environmental noise, the oscillators ultimately synchronize. However the approach to synchrony depends on whether or not dispersal in the absence of noise supports any stable asynchronous states. We also show how the combination of partially correlated noise with dispersal can lead to a multistable steady-state probability density. © 2012 Springer-Verlag Berlin Heidelberg.

  12. Crowd synchrony and quorum sensing in delay-coupled lasers

    CERN Document Server

    Zamora-Munt, Jordi; Garcia-Ojalvo, Jordi; Roy, Rajarshi

    2010-01-01

    Crowd synchrony and quorum sensing arise when a large number of dynamical elements communicate with each other via a common information pool. Previous evidence in different fields, including chemistry, biology and civil engineering, has shown that this type of coupling leads to synchronization, when coupling is instantaneous and the number of coupled elements is large enough. Here we consider a situation in which the transmission of information between the system components and the coupling pool is not instantaneous. To that end, we model a system of semiconductor lasers optically coupled to a central laser with a delay. Our results show that, even though the lasers are non-identical due to their distinct optical frequencies, zero-lag synchronization arises. By changing a system parameter, we can switch between two different types of synchronization transition. The dependence of the transition with respect to the delay-coupling parameters is studied.

  13. Higher Order Spike Synchrony in Prefrontal Cortex during visual memory

    Directory of Open Access Journals (Sweden)

    Gordon ePipa

    2011-06-01

    Full Text Available Precise temporal synchrony of spike firing has been postulated as an important neuronal mechanism for signal integration and the induction of plasticity in neocortex. As prefrontal cortex plays an important role in organizing memory and executive functions, the convergence of multiple visual pathways onto PFC predicts that neurons should preferentially synchronize their spiking when stimulus information is processed. Furthermore, synchronous spike firing should intensify if memory processes require the induction of neuronal plasticity, even if this is only for short-term. Here we show with multiple simultaneously recorded units in ventral prefrontal cortex that neurons participate in 3 ms precise synchronous discharges distributed across multiple sites separated by at least 500 µm. The frequency of synchronous firing is modulated by behavioral performance and is specific for the memorized visual stimuli. In particular, during the memory period in which activity is not stimulus driven, larger groups of up to 7 sites exhibit performance dependent modulation of their spike synchronization.

  14. SPIKY: a graphical user interface for monitoring spike train synchrony.

    Science.gov (United States)

    Kreuz, Thomas; Mulansky, Mario; Bozanic, Nebojsa

    2015-05-01

    Techniques for recording large-scale neuronal spiking activity are developing very fast. This leads to an increasing demand for algorithms capable of analyzing large amounts of experimental spike train data. One of the most crucial and demanding tasks is the identification of similarity patterns with a very high temporal resolution and across different spatial scales. To address this task, in recent years three time-resolved measures of spike train synchrony have been proposed, the ISI-distance, the SPIKE-distance, and event synchronization. The Matlab source codes for calculating and visualizing these measures have been made publicly available. However, due to the many different possible representations of the results the use of these codes is rather complicated and their application requires some basic knowledge of Matlab. Thus it became desirable to provide a more user-friendly and interactive interface. Here we address this need and present SPIKY, a graphical user interface that facilitates the application of time-resolved measures of spike train synchrony to both simulated and real data. SPIKY includes implementations of the ISI-distance, the SPIKE-distance, and the SPIKE-synchronization (an improved and simplified extension of event synchronization) that have been optimized with respect to computation speed and memory demand. It also comprises a spike train generator and an event detector that makes it capable of analyzing continuous data. Finally, the SPIKY package includes additional complementary programs aimed at the analysis of large numbers of datasets and the estimation of significance levels. Copyright © 2015 the American Physiological Society.

  15. Classifying Motion.

    Science.gov (United States)

    Duzen, Carl; And Others

    1992-01-01

    Presents a series of activities that utilizes a leveling device to classify constant and accelerated motion. Applies this classification system to uniform circular motion and motion produced by gravitational force. (MDH)

  16. Cluster synchrony in systems of coupled phase oscillators with higher-order coupling.

    Science.gov (United States)

    Skardal, Per Sebastian; Ott, Edward; Restrepo, Juan G

    2011-09-01

    We study the phenomenon of cluster synchrony that occurs in ensembles of coupled phase oscillators when higher-order modes dominate the coupling between oscillators. For the first time, we develop a complete analytic description of the dynamics in the limit of a large number of oscillators and use it to quantify the degree of cluster synchrony, cluster asymmetry, and switching. We use a variation of the recent dimensionality-reduction technique of Ott and Antonsen [Chaos 18, 037113 (2008)] and find an analytic description of the degree of cluster synchrony valid on a globally attracting manifold. Shaped by this manifold, there is an infinite family of steady-state distributions of oscillators, resulting in a high degree of multistability in the cluster asymmetry. We also show how through external forcing the degree of asymmetry can be controlled, and suggest that systems displaying cluster synchrony can be used to encode and store data.

  17. Synchrony dynamics during initiation, failure, and rescue of the segmentation clock.

    Science.gov (United States)

    Riedel-Kruse, Ingmar H; Müller, Claudia; Oates, Andrew C

    2007-09-28

    The "segmentation clock" is thought to coordinate sequential segmentation of the body axis in vertebrate embryos. This clock comprises a multicellular genetic network of synchronized oscillators, coupled by intercellular Delta-Notch signaling. How this synchrony is established and how its loss determines the position of segmentation defects in Delta and Notch mutants are unknown. We analyzed the clock's synchrony dynamics by varying strength and timing of Notch coupling in zebra-fish embryos with techniques for quantitative perturbation of gene function. We developed a physical theory based on coupled phase oscillators explaining the observed onset and rescue of segmentation defects, the clock's robustness against developmental noise, and a critical point beyond which synchrony decays. We conclude that synchrony among these genetic oscillators can be established by simultaneous initiation and self-organization and that the segmentation defect position is determined by the difference between coupling strength and noise.

  18. Cluster Synchrony in Systems of Coupled Phase Oscillators with Higher-Order Coupling

    CERN Document Server

    Skardal, Per Sebastian; Restrepo, Juan G

    2011-01-01

    We study the phenomenon of cluster synchrony that occurs in ensembles of coupled phase oscillators when higher-order modes dominate the coupling between oscillators. For the first time, we develop a complete analytic description of the dynamics in the limit of a large number of oscillators and use it to quantify the degree of cluster synchrony, cluster asymmetry, and switching. We use a variation of the recent dimensionality-reduction technique of Ott and Antonsen \\cite{OA1} and find an analytic description of the degree of cluster synchrony valid on a globally attracting manifold. Shaped by this manifold, there is an infinite family of steady-state distributions of oscillators, resulting in a high degree of multi-stability in the cluster asymmetry. We also show how through external forcing the degree of asymmetry can be controlled, and suggest that systems displaying cluster synchrony can be used to encode and store data.

  19. Effects of flowering phenology and synchrony on the reproductive success of a long-flowering shrub

    OpenAIRE

    Rodríguez-Pérez, Javier; Traveset, Anna

    2016-01-01

    Flowering phenology and synchrony with biotic and abiotic resources are crucial traits determining the reproductive success in insect-pollinated plants. In seasonal climates, plants flowering for long periods should assure reproductive success when resources are more predictable. In this work, we evaluated the relationship between flowering phenology and synchrony and reproductive success in Hypericum balearicum, a shrub flowering all year round but mainly during spring and summer. We studied...

  20. Mosquito Species (Diptera: Culicidae) Persistence and Synchrony Across an Urban Altitudinal Gradient.

    Science.gov (United States)

    Chaves, Luis Fernando

    2017-03-01

    Patterns of mosquito spatial persistence and temporal presence, as well as synchrony, i.e., the degree of concerted fluctuations in abundance, have been scarcely studied at finely grained spatial scales and over altitudinal gradients. Here, we present a spatial persistence, temporal presence, and synchrony analysis of four common mosquito species across the altitudinal gradient of Mt. Konpira in Nagasaki, Japan. We found that Aedes albopictus (Skuse) was more frequently found at the mountain base. In contrast, Aedes japonicus (Theobald) and Aedes flavopictus Yamada were common higher in the mountain, while Armigeres subalbatus (Coquillet) was uniformly present across the mountain, yet less frequently than the other species during the studied period. Our analysis showed that these spatial heterogeneities were associated with differences in landscape and microclimatic elements of Mt. Konpira. Temporally we found that presence across sampling locations was mainly synchronous across the four species and positively associated with rainfall and temperature. With the exception of Ae albopictus, where no significant synchrony was observed, mosquito species mainly showed flat synchrony profiles in Mt. Konpira when looking at the geographic (2-D) distance between their sampling locations. By contrast, when synchrony was studied across altitude, it was observed that Ae. flavopictus tracked the temperature synchrony pattern, decreasing its synchrony with the separation in altitude between sampling locations. Finally, our results suggest that differences in mosquito species persistence, temporal presence, and synchrony might be useful to understand the entomological risk of vector-borne disease transmission in urban landscapes. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  1. Mate guarding and territorial aggression vary with breeding synchrony in golden whistlers ( Pachycephala pectoralis)

    Science.gov (United States)

    van Dongen, Wouter F. D.

    2008-06-01

    Male paternity assurance behaviour during the female fertile period has been widely documented amongst birds. In contrast, how sex-specific behavioural strategies vary with local breeding synchrony levels remains largely unknown. This is important because, in many species, intra-population patterns of extra-pair fertilisation rates, and hence cuckoldry risk, are known to vary with the number of simultaneously fertile females. Each sex may therefore differ in how they behave towards male conspecifics during different degrees of breeding synchrony. Here I provide evidence of such sex-specific differences in the golden whistler ( Pachycephala pectoralis), a species in which within-pair paternity assurance is negatively associated with breeding synchrony. Via simulated territorial intrusions using decoy males, I show that males, but not females, increase levels of aggression to male intruders during periods of low synchrony, possibly because cuckoldry risk is greatest during this period. In addition, males appear to invest more effort into mate guarding after, but not before, territorial intrusions during this period. These inter-sexual differences may reflect conflicts in interest between the sexes, with females consistently showing interest in males during the fertile period regardless of synchrony levels and males investing more resources into expelling intruders when the risk of paternity loss is greatest. This study thus provides evidence that males may be able to detect variation in breeding synchrony and cuckoldry risk and adjust their paternity assurance behaviour accordingly.

  2. Audiovisual Temporal Recalibration for Speech in Synchrony Perception and Speech Identification

    Science.gov (United States)

    Asakawa, Kaori; Tanaka, Akihiro; Imai, Hisato

    We investigated whether audiovisual synchrony perception for speech could change after observation of the audiovisual temporal mismatch. Previous studies have revealed that audiovisual synchrony perception is re-calibrated after exposure to a constant timing difference between auditory and visual signals in non-speech. In the present study, we examined whether this audiovisual temporal recalibration occurs at the perceptual level even for speech (monosyllables). In Experiment 1, participants performed an audiovisual simultaneity judgment task (i.e., a direct measurement of the audiovisual synchrony perception) in terms of the speech signal after observation of the speech stimuli which had a constant audiovisual lag. The results showed that the “simultaneous” responses (i.e., proportion of responses for which participants judged the auditory and visual stimuli to be synchronous) at least partly depended on exposure lag. In Experiment 2, we adopted the McGurk identification task (i.e., an indirect measurement of the audiovisual synchrony perception) to exclude the possibility that this modulation of synchrony perception was solely attributable to the response strategy using stimuli identical to those of Experiment 1. The characteristics of the McGurk effect reported by participants depended on exposure lag. Thus, it was shown that audiovisual synchrony perception for speech could be modulated following exposure to constant lag both in direct and indirect measurement. Our results suggest that temporal recalibration occurs not only in non-speech signals but also in monosyllabic speech at the perceptual level.

  3. Oxytocin enhances inter-brain synchrony during social coordination in male adults.

    Science.gov (United States)

    Mu, Yan; Guo, Chunyan; Han, Shihui

    2016-12-01

    Recent brain imaging research has revealed oxytocin (OT) effects on an individual's brain activity during social interaction but tells little about whether and how OT modulates the coherence of inter-brain activity related to two individuals' coordination behavior. We developed a new real-time coordination game that required two individuals of a dyad to synchronize with a partner (coordination task) or with a computer (control task) by counting in mind rhythmically. Electroencephalography (EEG) was recorded simultaneously from a dyad to examine OT effects on inter-brain synchrony of neural activity during interpersonal coordination. Experiment 1 found that dyads showed smaller interpersonal time lags of counting and greater inter-brain synchrony of alpha-band neural oscillations during the coordination (vs control) task and these effects were reliably observed in female but not male dyads. Moreover, the increased alpha-band inter-brain synchrony predicted better interpersonal behavioral synchrony across all participants. Experiment 2, using a double blind, placebo-controlled between-subjects design, revealed that intranasal OT vs placebo administration in male dyads improved interpersonal behavioral synchrony in both the coordination and control tasks but specifically enhanced alpha-band inter-brain neural oscillations during the coordination task. Our findings provide first evidence that OT enhances inter-brain synchrony in male adults to facilitate social coordination. © The Author (2016). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

  4. Measuring Group Synchrony: A Cluster-Phase Method for Analyzing Multivariate Movement Time-Series

    Directory of Open Access Journals (Sweden)

    Michael eRichardson

    2012-10-01

    Full Text Available A new method for assessing group synchrony is introduced as being potentially useful for objectively determining degree of group cohesiveness or entitativity. The cluster-phase method of Frank and Richardson (2010 was used to analyze movement data from the rocking chair movements of six-member groups who rocked their chairs while seated in a circle facing the center. In some trials group members had no information about others’ movements (their eyes were shut or they had their eyes open and gazed at a marker in the center of the group. As predicted, the group level synchrony measure was able to distinguish between situations where synchrony would have been possible and situations where it would be impossible. Moreover, other aspects of the analysis illustrated how the cluster phase measures can be used to determine the type of patterning of group synchrony, and, when integrated with multi-level modeling, can be used to examine individual-level differences in synchrony and dyadic level synchrony as well.

  5. Temporally increasing spatial synchrony of North American temperature and bird populations

    Science.gov (United States)

    Koenig, Walter D.; Liebhold, Andrew M.

    2016-06-01

    The ecological impacts of modern global climate change are detectable in a wide variety of phenomena, ranging from shifts in species ranges to changes in community composition and human disease dynamics. So far, however, little attention has been given to temporal changes in spatial synchrony--the coincident change in abundance or value across the landscape--despite the importance of environmental synchrony as a driver of population trends and the central role of environmental variability in population rescue and extinction. Here we demonstrate that across North America, spatial synchrony of a significant proportion of 49 widespread North American wintering bird species has increased over the past 50 years--the period encompassing particularly intense anthropogenic effects in climate--paralleling significant increases in spatial synchrony of mean maximum air temperature. These results suggest the potential for increased spatial synchrony in environmental factors to be affecting a wide range of ecological phenomena. These effects are likely to vary, but for North American wildlife species, increased spatial synchrony driven by environmental factors may be the basis for a previously unrecognized threat to their long-term persistence in the form of more synchronized population dynamics reducing the potential for demographic rescue among interacting subpopulations.

  6. Estrous synchrony in a group of African elephants (Loxodonta africana) under human care.

    Science.gov (United States)

    Weissenböck, Nicole M; Schwammer, Harald M; Ruf, Thomas

    2009-07-01

    Synchrony of estrous, and consequently of conception and birth of young, may be of adaptive significance for certain mammals. Among the species in which estrous synchrony has been suspected several times are elephants, but clear evidence is still missing. We determined estrous cycles of African elephants (Loxodonta africana) (n=4) at the Vienna Zoo, Austria, between June 2003 and January 2006 by measuring serum progesterone levels from weekly blood samples. Except for the dominant female when she was intensively lactating, all animals showed clear cycles or progesterone release with a mean period of 105.3+/-15.37 days. For most of the study period, estrous cycles were asynchronous between females. However, after re-occurrence of the progesterone cycle in the dominant female following the first period of lactation, all four females showed high synchrony of progesterone release over the two subsequent cycles. Large changes in individual period lengths indicated that synchronization was due to the adjustment of cycle length in subdominants to that of the dominant female. We used a bootstrap procedure, based on resampling measured times of progesterone peaks, to determine if this apparent synchrony could have been caused by chance alone. This statistical analysis indicated that between-individual variances of the timing of progesterone peaks were much smaller that to be expected by chance (P=0.009). This finding represents the first evidence for estrous synchrony between elephants. We discuss various hypotheses to explain the biological function of cycle synchrony in elephants.

  7. Rectangular Blocks vs Polygonal Walls in Archaeoseismology

    Directory of Open Access Journals (Sweden)

    Klaus-G. Hinzen

    2017-07-01

    Full Text Available Collapsed or deformed walls in ancient structures constitute important evidence in archaeoseismology, where damage is interpreted in terms of earthquake ground motion. A large variety of wall types have been developed during the millennia in different cultural backgrounds. Often walls with polygonal-shaped building blocks are regarded as more earthquake-resistant than a wall consisting of rectangular elements and, as is sometimes speculated, that the irregular wall types were intentionally developed for that purpose. We use simply structured discrete element models of four walls with different block geometries, perfect rectangular, an Inka-type structure and two polygonal designs, to test their dynamic behavior. In addition to an analytic calculation of ground motion, we use measured strong motion signals as boundary conditions for the 3D wall models with varying height to width ratios. At peak ground accelerations between 1.0 and 9.0 m/s2 and major frequencies of 0.5 to 3 Hz, numeric experiments with the horizontally applied analytic ground motions result in clear differences in the resistance of the four wall types with the rectangular block wall being most vulnerable. For more complex measured 3D motions the Inka-type wall proves more stable than the rectangular block wall; however, height to width ratio still has equally strong influence on the stability. Internal deformation of non-collapsed walls shows some correlation with the parameters of the driving motion. For simple impulsive ground motions, a peak ground displacement threshold exists between toppling and remaining upright for all four models but peak acceleration cannot be reliably back calculated.

  8. Brain-to-Brain Synchrony Tracks Real-World Dynamic Group Interactions in the Classroom.

    Science.gov (United States)

    Dikker, Suzanne; Wan, Lu; Davidesco, Ido; Kaggen, Lisa; Oostrik, Matthias; McClintock, James; Rowland, Jess; Michalareas, Georgios; Van Bavel, Jay J; Ding, Mingzhou; Poeppel, David

    2017-05-08

    The human brain has evolved for group living [1]. Yet we know so little about how it supports dynamic group interactions that the study of real-world social exchanges has been dubbed the "dark matter of social neuroscience" [2]. Recently, various studies have begun to approach this question by comparing brain responses of multiple individuals during a variety of (semi-naturalistic) tasks [3-15]. These experiments reveal how stimulus properties [13], individual differences [14], and contextual factors [15] may underpin similarities and differences in neural activity across people. However, most studies to date suffer from various limitations: they often lack direct face-to-face interaction between participants, are typically limited to dyads, do not investigate social dynamics across time, and, crucially, they rarely study social behavior under naturalistic circumstances. Here we extend such experimentation drastically, beyond dyads and beyond laboratory walls, to identify neural markers of group engagement during dynamic real-world group interactions. We used portable electroencephalogram (EEG) to simultaneously record brain activity from a class of 12 high school students over the course of a semester (11 classes) during regular classroom activities (Figures 1A-1C; Supplemental Experimental Procedures, section S1). A novel analysis technique to assess group-based neural coherence demonstrates that the extent to which brain activity is synchronized across students predicts both student class engagement and social dynamics. This suggests that brain-to-brain synchrony is a possible neural marker for dynamic social interactions, likely driven by shared attention mechanisms. This study validates a promising new method to investigate the neuroscience of group interactions in ecologically natural settings. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  9. A Framework for Group Key Management Protocol Assessment Independent of View Synchrony

    Directory of Open Access Journals (Sweden)

    David Manz

    2010-01-01

    Full Text Available Problem statement: As group key management extended into the area of large dynamic networks, complex issues emerged involving the many operations that run over several network topologies. The issues that occurred due to multiple topologies were also compounded by differing views of the network, taken at different time slices or positions within the network. This was especially complex when figuring in mobile, ad-hoc networks. View synchrony is the current operational technique, or assumption, applied to group key exchange protocols. However, before this analysis view synchrony was just that, an assumption and the literature for group key exchange lacked an inquiry into what could happen when view synchrony was removed. Current group key management protocols rely on view synchrony and yet all protocols vary in requisite operational descriptions and performance measures. In this study, a framework for group key management protocol operations and performance measures was defined and examined how that framework could be used to compare and contrast existing protocols with and, more importantly, without view synchrony. Approach: Current literature lacked categories by which to quantify the performance metric of the protocols. This study first defined the dynamic key operations that all protocols share. By these definitions, group key management protocols were directly compared. Once definitions existed, this study assembled a list of costs that every protocol requires to establish and share keys across the dynamic group. These results provided an understanding of view synchrony's role and whether or not it should be solely relied on in these current protocols. Results: The prior conclusion that view synchrony was an integral part of all group key management protocols was shattered, when seen through the lens of communication costs and assumptions in wireless ad-hoc networks. View synchrony, as an assumed part of all group key management was

  10. Movement Synchrony Forges Social Bonds Across Group Divides

    Directory of Open Access Journals (Sweden)

    Bahar eTuncgenc

    2016-05-01

    Full Text Available Group dynamics play an important role in the social interactions of both children and adults. A large amount of research has shown that merely being allocated to arbitrarily defined groups can evoke disproportionately positive attitudes toward one’s in-group and negative attitudes toward out-groups, and that these biases emerge in early childhood. This prompts important empirical questions with far-reaching theoretical and applied significance. How robust are these inter-group biases? Can biases be mitigated by behaviors known to bond individuals and groups together? How can bonds be forged across existing group divides? To explore these questions, we examined the bonding effects of interpersonal synchrony on minimally constructed groups in a controlled experiment. In-group and out-group bonding were assessed using questionnaires administered before and after a task in which groups performed movements either synchronously or non-synchronously in a between-participants design. We also developed an implicit behavioral measure, the Island Game, in which physical proximity was used as an indirect measure of interpersonal closeness. Self-report and behavioral measures showed increased bonding between groups after synchronous movement. Bonding with the out-group was significantly higher in the condition in which movements were performed synchronously than when movements were performed non-synchronously between groups. The findings are discussed in terms of their importance for the developmental social psychology of group dynamics as well as their implications for applied intervention programs.

  11. Interaction between Olfaction and Gustation by Using Synchrony Perception Task

    Directory of Open Access Journals (Sweden)

    Tatsu Kobayakawa

    2011-10-01

    Full Text Available It seems that interaction between olfaction (smell sensation and gustation (taste sensation will stronger than other interactions among five senses, although no one has ever confirmed psychophysically. In this study, we utilized synchrony perception task to confirm this specificity comparing control condition, interaction between vision and olfaction and one between vision and gustation. We used NaCl as taste stimuli and flavor from bubbling chicken stock as olfactory stimuli. We used taste stimulator which was able to present pure gustation without tactile stimuli, and smell stimulator with original developed real time stimulus monitoring. We used LED for vision stimuli. Timing of both stimuli was shifted from −1000 ms to +1000ms with each other, and participants were instructed to judge synchronicity. Control conditions revealed that olfaction and gustation has almost equivalent temporal resolution to other sensations. And probability distribution between olfaction and gustation was quite different from other interactions including vision. These results shows interaction between olfaction and gustation is more specific.

  12. Ising-like patterns of spatial synchrony in population biology

    Science.gov (United States)

    Noble, Andrew; Hastings, Alan; Machta, Jon

    2014-03-01

    Systems of coupled dynamical oscillators can undergo a phase transition between synchronous and asynchronous phases. In the case of coupled map lattices, the spontaneous symmetry breaking of a temporal-phase order parameter is known to exhibit Ising-like critical behavior. Here, we investigate a noisy coupled map motivated by the study of spatial synchrony in ecological populations far from the extinction threshold. Ising-like patterns of criticality, as well as spinodal decomposition and homogeneous nucleation, emerge from the nonlinear interactions of environmental fluctuations in habitat quality, local density-dependence in reproduction, and dispersal. In the mean-field limit, the correspondence to the Ising model is exact: the fixed points of our dynamical system are given by the equation of state for Weiss mean-field theory under an appropriate mapping of parameters. We have strong evidence that a quantitative correspondence persists, both near and far from the critical point, in the presence of fluctuations. Our results provide a formal connection between equilibrium statistical physics and population biology. This work is supported by the National Science Foundation under Grant No. 1344187.

  13. Multisensory Interactions across Spatial Location and Temporal Synchrony

    Directory of Open Access Journals (Sweden)

    Ryan A Stevenson

    2011-10-01

    Full Text Available The process of integrating information across sensory modalities is highly dependent upon a number of stimulus characteristics, including spatial and temporal coincidence, as well as effectiveness. Typically, these properties have been studied in isolation, but recent evidence suggests that they are interactive. This study focuses on interactions between the spatial location and temporal synchrony of stimuli. Participants were presented with simple audiovisual in parametrically varied locations, and with parametrically varied stimulus onset asynchronies (SOAs. Participants performed spatial location and perceived simultaneity tasks (PSS. Accuracies and response times were measured. Accuracies of spatial localization were dependent upon spatial location, with no effect of SOA and interaction seen, however, RT analysis showed an effect of SOA and an interaction; more peripheral presentations showed greater slowing of RT in asynchronous conditions, and fewer violations of the race model. With the PSS tasks, effects of SOA and spatial location were found in the responses, as well as an interaction between the two. Peripheral stimuli were more likely to be judged as synchronous, a difference seen particularly with long SOAs. These results suggest that the commonly studied principles of integration are indeed interactive, and that these interactions have measureable behavioral implications.

  14. Structure of axionic domain walls

    Science.gov (United States)

    Huang, M. C.; Sikivie, P.

    1985-09-01

    The structure of axionic domain walls is investigated using the low-energy effective theory of axions and pions. We derive the spatial dependence of the phases of the Peccei-Quinn scalar field and the QCD quark-antiquark condensates inside an axionic domain wall. Thence an accurate estimate of the wall surface energy density is obtained. The equations of motion for axions, photons, leptons, and baryons in the neighborhood of axionic domain walls are written down and estimates are given for the wall reflection and transmission coefficients of these particles. Finally, we discuss the energy dissipation by axionic domain walls oscillating in the early universe due to the reflection of particles in the primordial soup.

  15. Structure of axionic domain walls

    Energy Technology Data Exchange (ETDEWEB)

    Huang, M.C.; Sikivie, P.

    1985-09-15

    The structure of axionic domain walls is investigated using the low-energy effective theory of axions and pions. We derive the spatial dependence of the phases of the Peccei-Quinn scalar field and the QCD quark-antiquark condensates inside an axionic domain wall. Thence an accurate estimate of the wall surface energy density is obtained. The equations of motion for axions, photons, leptons, and baryons in the neighborhood of axionic domain walls are written down and estimates are given for the wall reflection and transmission coefficients of these particles. Finally, we discuss the energy dissipation by axionic domain walls oscillating in the early universe due to the reflection of particles in the primordial soup.

  16. Infanticide and within-clutch competition select for reproductive synchrony in a cooperative bird.

    Science.gov (United States)

    Riehl, Christina

    2016-08-01

    Reproduction among members of social animal groups is often highly synchronized, but neither the selective advantages nor the proximate causes of synchrony are fully understood. Here I investigate the evolution of hatching synchrony in the Greater Ani (Crotophaga major), a communally nesting bird in which several unrelated females contribute eggs to a large, shared clutch. Hatching synchrony is variable, ranging from complete synchrony to moderate asynchrony, and is determined by the onset of incubation of the communal clutch. Data from a 10-year field study indicate that individual reproductive success is highest in synchronous groups, and that nestlings that hatch in the middle of the hatching sequence are most likely to survive. Nestling mortality is high in asynchronous clutches because early-hatching nestlings are more likely to be killed by adult group members, whereas late-hatching nestlings are more likely to starve due competition with their older nest-mates. Therefore, the timing of hatching appears to be under stabilizing selection from infanticide and resource competition acting in concert. These results provide empirical support for models predicting that synchrony may evolve as an adaptive counter-strategy to infanticide, and they highlight the importance of competition in shaping the timing of reproduction in social groups.

  17. Temporal Synchrony Detection and Associations with Language in Young Children with ASD

    Directory of Open Access Journals (Sweden)

    Elena Patten

    2014-01-01

    Full Text Available Temporally synchronous audio-visual stimuli serve to recruit attention and enhance learning, including language learning in infants. Although few studies have examined this effect on children with autism, it appears that the ability to detect temporal synchrony between auditory and visual stimuli may be impaired, particularly given social-linguistic stimuli delivered via oral movement and spoken language pairings. However, children with autism can detect audio-visual synchrony given nonsocial stimuli (objects dropping and their corresponding sounds. We tested whether preschool children with autism could detect audio-visual synchrony given video recordings of linguistic stimuli paired with movement of related toys in the absence of faces. As a group, children with autism demonstrated the ability to detect audio-visual synchrony. Further, the amount of time they attended to the synchronous condition was positively correlated with receptive language. Findings suggest that object manipulations may enhance multisensory processing in linguistic contexts. Moreover, associations between synchrony detection and language development suggest that better processing of multisensory stimuli may guide and direct attention to communicative events thus enhancing linguistic development.

  18. Audio-visual synchrony and feature-selective attention co-amplify early visual processing.

    Science.gov (United States)

    Keitel, Christian; Müller, Matthias M

    2016-05-01

    Our brain relies on neural mechanisms of selective attention and converging sensory processing to efficiently cope with rich and unceasing multisensory inputs. One prominent assumption holds that audio-visual synchrony can act as a strong attractor for spatial attention. Here, we tested for a similar effect of audio-visual synchrony on feature-selective attention. We presented two superimposed Gabor patches that differed in colour and orientation. On each trial, participants were cued to selectively attend to one of the two patches. Over time, spatial frequencies of both patches varied sinusoidally at distinct rates (3.14 and 3.63 Hz), giving rise to pulse-like percepts. A simultaneously presented pure tone carried a frequency modulation at the pulse rate of one of the two visual stimuli to introduce audio-visual synchrony. Pulsed stimulation elicited distinct time-locked oscillatory electrophysiological brain responses. These steady-state responses were quantified in the spectral domain to examine individual stimulus processing under conditions of synchronous versus asynchronous tone presentation and when respective stimuli were attended versus unattended. We found that both, attending to the colour of a stimulus and its synchrony with the tone, enhanced its processing. Moreover, both gain effects combined linearly for attended in-sync stimuli. Our results suggest that audio-visual synchrony can attract attention to specific stimulus features when stimuli overlap in space.

  19. Making children laugh: parent-child dyadic synchrony and preschool attachment.

    Science.gov (United States)

    Bureau, Jean-FrançOis; Yurkowski, Kim; Schmiedel, Sabrina; Martin, Jodi; Moss, Ellen; Pallanca, Dominique

    2014-01-01

    The current study examined whether dyadic synchrony of father-child and mother-child interactions in a playful context were associated with attachment organization in preschool children. One hundred seven children (48 boys, Mage = 46.67 months, SD = 8.57) and their mothers and fathers (counterbalanced order of lab visits) participated in a playful interaction without toys (Laughing Task procedure). Playful interactions were coded based on the degree to which the dyads demonstrated a variety of behavior representing dyadic synchrony and task management. Children's attachment behavior toward fathers and mothers was observed in a modified separation-reunion procedure adapted for the preschool period. Results demonstrate that mothers and fathers are similar in their effort to arouse and engage their child in a playful context, but mothers achieved a greater synchrony with their child. Disorganized attachment to either mother or father is linked with a lack of synchrony in dyadic interaction. Findings are in contrast with prevailing theory, suggesting that despite gender-related differences in parental playful behaviors, dyadic synchrony is equally important in both mother- and father-child relationships for the development of organized social and affectional bonds.

  20. Population synchrony of a native fish across three Laurentian Great Lakes: Evaluating the effects of dispersal and climate

    Science.gov (United States)

    Bunnell, D.B.; Adams, J.V.; Gorman, O.T.; Madenjian, C.P.; Riley, S.C.; Roseman, E.F.; Schaeffer, J.S.

    2010-01-01

    Climate and dispersal are the two most commonly cited mechanisms to explain spatial synchrony among time series of animal populations, and climate is typically most important for fishes. Using data from 1978-2006, we quantified the spatial synchrony in recruitment and population catch-per-unit-effort (CPUE) for bloater (Coregonus hoyi) populations across lakes Superior, Michigan, and Huron. In this natural field experiment, climate was highly synchronous across lakes but the likelihood of dispersal between lakes differed. When data from all lakes were pooled, modified correlograms revealed spatial synchrony to occur up to 800 km for long-term (data not detrended) trends and up to 600 km for short-term (data detrended by the annual rate of change) trends. This large spatial synchrony more than doubles the scale previously observed in freshwater fish populations, and exceeds the scale found in most marine or estuarine populations. When analyzing the data separately for within- and between-lake pairs, spatial synchrony was always observed within lakes, up to 400 or 600 km. Conversely, between-lake synchrony did not occur among short-term trends, and for long-term trends, the scale of synchrony was highly variable. For recruit CPUE, synchrony occurred up to 600 km between both lakes Michigan and Huron (where dispersal was most likely) and lakes Michigan and Superior (where dispersal was least likely), but failed to occur between lakes Huron and Superior (where dispersal likelihood was intermediate). When considering the scale of putative bloater dispersal and genetic information from previous studies, we concluded that dispersal was likely underlying within-lake synchrony but climate was more likely underlying between-lake synchrony. The broad scale of synchrony in Great Lakes bloater populations increases their probability of extirpation, a timely message for fishery managers given current low levels of bloater abundance. ?? Springer-Verlag 2009.

  1. Out-of-synchrony speech entrainment in developmental dyslexia.

    Science.gov (United States)

    Molinaro, Nicola; Lizarazu, Mikel; Lallier, Marie; Bourguignon, Mathieu; Carreiras, Manuel

    2016-08-01

    Developmental dyslexia is a reading disorder often characterized by reduced awareness of speech units. Whether the neural source of this phonological disorder in dyslexic readers results from the malfunctioning of the primary auditory system or damaged feedback communication between higher-order phonological regions (i.e., left inferior frontal regions) and the auditory cortex is still under dispute. Here we recorded magnetoencephalographic (MEG) signals from 20 dyslexic readers and 20 age-matched controls while they were listening to ∼10-s-long spoken sentences. Compared to controls, dyslexic readers had (1) an impaired neural entrainment to speech in the delta band (0.5-1 Hz); (2) a reduced delta synchronization in both the right auditory cortex and the left inferior frontal gyrus; and (3) an impaired feedforward functional coupling between neural oscillations in the right auditory cortex and the left inferior frontal regions. This shows that during speech listening, individuals with developmental dyslexia present reduced neural synchrony to low-frequency speech oscillations in primary auditory regions that hinders higher-order speech processing steps. The present findings, thus, strengthen proposals assuming that improper low-frequency acoustic entrainment affects speech sampling. This low speech-brain synchronization has the strong potential to cause severe consequences for both phonological and reading skills. Interestingly, the reduced speech-brain synchronization in dyslexic readers compared to normal readers (and its higher-order consequences across the speech processing network) appears preserved through the development from childhood to adulthood. Thus, the evaluation of speech-brain synchronization could possibly serve as a diagnostic tool for early detection of children at risk of dyslexia. Hum Brain Mapp 37:2767-2783, 2016. © 2016 Wiley Periodicals, Inc.

  2. Perceived synchrony for realistic and dynamic audiovisual events.

    Science.gov (United States)

    Eg, Ragnhild; Behne, Dawn M

    2015-01-01

    In well-controlled laboratory experiments, researchers have found that humans can perceive delays between auditory and visual signals as short as 20 ms. Conversely, other experiments have shown that humans can tolerate audiovisual asynchrony that exceeds 200 ms. This seeming contradiction in human temporal sensitivity can be attributed to a number of factors such as experimental approaches and precedence of the asynchronous signals, along with the nature, duration, location, complexity and repetitiveness of the audiovisual stimuli, and even individual differences. In order to better understand how temporal integration of audiovisual events occurs in the real world, we need to close the gap between the experimental setting and the complex setting of everyday life. With this work, we aimed to contribute one brick to the bridge that will close this gap. We compared perceived synchrony for long-running and eventful audiovisual sequences to shorter sequences that contain a single audiovisual event, for three types of content: action, music, and speech. The resulting windows of temporal integration showed that participants were better at detecting asynchrony for the longer stimuli, possibly because the long-running sequences contain multiple corresponding events that offer audiovisual timing cues. Moreover, the points of subjective simultaneity differ between content types, suggesting that the nature of a visual scene could influence the temporal perception of events. An expected outcome from this type of experiment was the rich variation among participants' distributions and the derived points of subjective simultaneity. Hence, the designs of similar experiments call for more participants than traditional psychophysical studies. Heeding this caution, we conclude that existing theories on multisensory perception are ready to be tested on more natural and representative stimuli.

  3. EFFECT OF DIFFERENT TYPES OF NEAR-FAULT PULSE GROUND MOTION ON FRAME-SHEAR WALL STRUCTURE%不同类型近断层脉冲型地震动对框架-剪力墙结构的影响

    Institute of Scientific and Technical Information of China (English)

    李明; 刘勇; 孙哲哲; 袁赫

    2015-01-01

    近断层脉冲型地震动对结构有很大的潜在破坏作用.为分析不同类型该类地震动对框架剪力墙结构地震反应的影响,搜集了近断层双脉冲和多脉冲型地震动,计算了这些地震动的加速度反应谱,及其引起的一个22层钢筋混凝土框架-剪力墙结构的时程反应.对比了双脉冲和多脉冲型地震动的平均弹性加速度反应谱,及其引起框架-剪力墙结构的平均基底剪力、平均最大层间位移角、平均顶层位移和平均结构整体破坏指数.结果表明:近断层双脉冲型地震动的平均弹性加速度反应谱谱值均接近或大于近断层多脉冲型地震动;近断层双脉冲型地震动引起的框架-剪力墙结构平均基底剪力、平均最大层间位移角、平均顶层位移和平均结构整体破坏指数均不小于近断层多脉冲型地震动.由此说明,在统计意义上,当分析近断层脉冲型地震动对框架-剪力墙结构破坏作用的影响时,输入地震动可近似仅考虑双脉冲型地震动.%Near-fault pulse ground motion has large potential damage effect on structure.In order to analyze the effect of this kind of ground motion on frame-shear wall structures,near-fault double-pulse-type and multi-pulse-type ground motion are collected.Their elastic acceleration response spectra and the time history response of a 22-floor concrete reinforced frame-shear wall structure induced by them are calculated.The average elastic acceleration response spectra of the near-fault double-pulse-type ground motion is compared with that of the multi-pulse-type ground motion.The average base shear,the average maximum storey-drift-angle,the average top floor displacement,and the average whole structure damage index induced by the near-fault double-pulse-type ground motion are also compared with those induced by the multi-pulse-type ground motion.The results show:the average elastic acceleration response spectra of the near-fault double

  4. Phase synchrony facilitates binding and segmentation of natural images in a coupled neural oscillator network.

    Science.gov (United States)

    Finger, Holger; König, Peter

    2013-01-01

    Synchronization has been suggested as a mechanism of binding distributed feature representations facilitating segmentation of visual stimuli. Here we investigate this concept based on unsupervised learning using natural visual stimuli. We simulate dual-variable neural oscillators with separate activation and phase variables. The binding of a set of neurons is coded by synchronized phase variables. The network of tangential synchronizing connections learned from the induced activations exhibits small-world properties and allows binding even over larger distances. We evaluate the resulting dynamic phase maps using segmentation masks labeled by human experts. Our simulation results show a continuously increasing phase synchrony between neurons within the labeled segmentation masks. The evaluation of the network dynamics shows that the synchrony between network nodes establishes a relational coding of the natural image inputs. This demonstrates that the concept of binding by synchrony is applicable in the context of unsupervised learning using natural visual stimuli.

  5. Phase synchrony facilitates binding and segmentation of natural images in a coupled neural oscillator network

    Directory of Open Access Journals (Sweden)

    Holger eFinger

    2014-01-01

    Full Text Available Synchronization has been suggested as a mechanism of binding distributed feature representations facilitating segmentation of visual stimuli. Here we investigate this concept based on unsupervised learning using natural visual stimuli. We simulate dual-variable neural oscillators with separate activation and phase variables. The binding of a set of neurons is coded by synchronized phase variables. The network of tangential synchronizing connections learned from the induced activations exhibits small-world properties and allows binding even over larger distances. We evaluate the resulting dynamic phase maps using segmentation masks labeled by human experts. Our simulation results show a continuously increasing phase synchrony between neurons within the labeled segmentation masks. The evaluation of the network dynamics shows that the synchrony between network nodes establishes a relational coding of the natural image inputs. This demonstrates that the concept of binding by synchrony is applicable in the context of unsupervised learning using natural visual stimuli.

  6. Prefrontally driven downregulation of neural synchrony mediates goal-directed forgetting.

    Science.gov (United States)

    Hanslmayr, Simon; Volberg, Gregor; Wimber, Maria; Oehler, Nora; Staudigl, Tobias; Hartmann, Thomas; Raabe, Markus; Greenlee, Mark W; Bäuml, Karl-Heinz T

    2012-10-17

    Neural synchronization between distant cell assemblies is crucial for the formation of new memories. To date, however, it remains unclear whether higher-order brain regions can adaptively regulate neural synchrony to control memory processing in humans. We explored this question in two experiments using a voluntary forgetting task. In the first experiment, we simultaneously recorded electroencephalography along with fMRI. The results show that a reduction in neural synchrony goes hand-in-hand with a BOLD signal increase in the left dorsolateral prefrontal cortex (dlPFC) when participants are cued to forget previously studied information. In the second experiment, we directly stimulated the left dlPFC with repetitive transcranial magnetic stimulation during the same task, and show that such stimulation specifically boosts the behavioral forgetting effect and induces a reduction in neural synchrony. These results suggest that prefrontally driven downregulation of long-range neural synchronization mediates goal-directed forgetting of long-term memories.

  7. More than reflections: empathy in motivational interviewing includes language style synchrony between therapist and client.

    Science.gov (United States)

    Lord, Sarah Peregrine; Sheng, Elisa; Imel, Zac E; Baer, John; Atkins, David C

    2015-05-01

    Empathy is a basic psychological process that involves the development of synchrony in dyads. It is also a foundational ingredient in specific, evidence-based behavioral treatments like motivational interviewing (MI). Ratings of therapist empathy typically rely on a gestalt, "felt sense" of therapist understanding and the presence of specific verbal behaviors like reflective listening. These ratings do not provide a direct test of psychological processes like behavioral synchrony that are theorized to be an important component of empathy in psychotherapy. To explore a new objective indicator of empathy, we hypothesized that synchrony in language style (i.e., matching how statements are phrased) between client and therapists would predict gestalt ratings of empathy over and above the contribution of reflections. We analyzed 122 MI transcripts with high and low empathy ratings based on the Motivational Interviewing Treatment Integrity global rating scale. Linguistic inquiry and word count was used to estimate language style synchrony (LSS) of adjacent client and therapist talk turns. High-empathy sessions showed greater LSS across 11 language style categories compared with low-empathy sessions (pempathy versus low-empathy sessions (d=0.62). Regression analyses showed that LSS was predictive of empathy ratings over and above reflection counts; a 1 SD increase in LSS is associated with a 2.4 times increase in the odds of a high-empathy rating, controlling for therapist reflections (odds ratio=2.4; 95% CI: 1.36; 4.24, pempathy ratings are related to synchrony in language style, over and above synchrony of content as measured by therapist reflections. Novel indicators of therapist empathy may have implications for the study of MI process as well as the training of therapists. Copyright © 2014. Published by Elsevier Ltd.

  8. Long-range synchrony in the gamma band: role in music perception.

    Science.gov (United States)

    Bhattacharya, J; Petsche, H; Pereda, E

    2001-08-15

    Synchronization seems to be a central mechanism for neuronal information processing within and between multiple brain areas. Furthermore, synchronization in the gamma band has been shown to play an important role in higher cognitive functions, especially by binding the necessary spatial and temporal information in different cortical areas to build a coherent perception. Specific task-induced (evoked) gamma oscillations have often been taken as an indication of synchrony, but the presence of long-range synchrony cannot be inferred from spectral power in the gamma range. We studied the usefulness of a relatively new measure, called similarity index to detect asymmetric interdependency between two brain regions. Spontaneous EEG from two groups-musicians and non-musicians-were recorded during several states: listening to music, listening to text, and at rest (eyes closed and eyes open). While listening to music, degrees of the gamma band synchrony over distributed cortical areas were found to be significantly higher in musicians than non-musicians. Yet no differences between these two groups were found at resting conditions and while listening to a neutral text. In contrast to the degree of long-range synchrony, spectral power in the gamma band was higher in non-musicians. The degree of spatial synchrony, a measure of signal complexity based on eigen-decomposition method, was also significantly increased in musicians while listening to music. As compared with non-musicians, the finding of increased long-range synchrony in musicians independent of spectral power is interpreted as a manifestation of a more advanced musical memory of musicians in binding together several features of the intrinsic complexity of music in a dynamical way.

  9. Nested synchrony – a novel cross-scale interaction among neuronal oscillations

    Directory of Open Access Journals (Sweden)

    Simo eMonto

    2012-09-01

    Full Text Available Neuronal interactions form the basis for our brain function, and oscillations and synchrony are the principal candidates for mediating them in the cortical networks. Phase synchrony, where oscillatory neuronal ensembles directly synchronize their phases, enables precise integration between separated brain regions. However, it is unclear how neuronal interactions are dynamically coordinated in space and over time. Cross-scale effects have been proposed to be responsible for linking levels of processing hierarchy and to regulate neuronal dynamics. Most notably, nested oscillations, where the phase of a neuronal oscillation modulates the amplitude of a faster one, may locally integrate neuronal activities in distinct frequency bands. Yet, hierarchical control of inter-areal synchrony could provide a more comprehensive view to the dynamical structure of oscillatory interdependencies in the human brain.In this study, the notion of nested oscillations is extended to a cross-frequency and inter-areal model of oscillatory interactions. In this model, the phase of a slower oscillation modulates inter-areal synchrony in a higher frequency band. This would allow cross-scale integration of global interactions and, thus, offers a mechanism for binding distributed neuronal activities.We show that inter-areal phase synchrony can be modulated by the phase of a slower neuronal oscillation using magnetoencephalography. This effect is the most pronounced at frequencies below 35 Hz. Importantly, changes in oscillation amplitudes did not explain the findings. We expect that the novel cross-frequency interaction could offer new ways to understand the flexible but accurate dynamic organization of ongoing neuronal oscillations and synchrony.

  10. Fractional motions

    Energy Technology Data Exchange (ETDEWEB)

    Eliazar, Iddo I., E-mail: eliazar@post.tau.ac.il [Holon Institute of Technology, P.O. Box 305, Holon 58102 (Israel); Shlesinger, Michael F., E-mail: mike.shlesinger@navy.mil [Office of Naval Research, Code 30, 875 N. Randolph St., Arlington, VA 22203 (United States)

    2013-06-10

    Brownian motion is the archetypal model for random transport processes in science and engineering. Brownian motion displays neither wild fluctuations (the “Noah effect”), nor long-range correlations (the “Joseph effect”). The quintessential model for processes displaying the Noah effect is Lévy motion, the quintessential model for processes displaying the Joseph effect is fractional Brownian motion, and the prototypical model for processes displaying both the Noah and Joseph effects is fractional Lévy motion. In this paper we review these four random-motion models–henceforth termed “fractional motions” –via a unified physical setting that is based on Langevin’s equation, the Einstein–Smoluchowski paradigm, and stochastic scaling limits. The unified setting explains the universal macroscopic emergence of fractional motions, and predicts–according to microscopic-level details–which of the four fractional motions will emerge on the macroscopic level. The statistical properties of fractional motions are classified and parametrized by two exponents—a “Noah exponent” governing their fluctuations, and a “Joseph exponent” governing their dispersions and correlations. This self-contained review provides a concise and cohesive introduction to fractional motions.

  11. Wonderful Walls

    Science.gov (United States)

    Greenman, Jim

    2006-01-01

    In this article, the author emphasizes the importance of "working" walls in children's programs. Children's programs need "working" walls (and ceilings and floors) which can be put to use for communication, display, storage, and activity space. The furnishings also work, or don't work, for the program in another sense: in aggregate, they serve as…

  12. Ambiguous walls

    DEFF Research Database (Denmark)

    Mody, Astrid

    2012-01-01

    The introduction of Light Emitting Diodes (LEDs) in the built environment has encouraged myriad applications, often embedded in surfaces as an integrated part of the architecture. Thus the wall as responsive luminous skin is becoming, if not common, at least familiar. Taking into account how wall...

  13. Detection of the short-term preseizure changes in EEG recordings using complexity and synchrony analysis

    Institute of Scientific and Technical Information of China (English)

    JIA Wenyan; KONG Na; MA Jun; LIU Hesheng; GAO Xiaorong; GAO Shangkai; YANG Fusheng

    2006-01-01

    An important consideration in epileptic seizure prediction is proving the existence of a pre-seizure state that can be detected using various signal processing algorithms. In the analyses of intracranial electroencephalographic (EEG)recordings of four epilepsy patients, the short-term changes in the measures of complexity and synchrony were detected before the majority of seizure events across the sample patient population. A decrease in complexity and increase in phase synchrony appeared several minutes before seizure onset and the changes were more pronounced in the focal region than in the remote region. This result was also validated statistically using a surrogate data method.

  14. Domain Wall Evolution in Phase Transforming Oxides

    Science.gov (United States)

    2015-01-14

    PERFORMING ORGANIZATION NAMES AND ADDRESSES 8. PERFORMI:N’G ORGANIZATION REPORT University ofFioridaOffice ofEngineering NUMBER 339 Wei I Hall ...surveillance, navigation, tlrreat identification, target acquisition, and missile guidance. Domain wall motion, or the planar defects separating regions of...surveillance, navigation, threat identification, target acquisition, and missile guidance. Domain wall motion, or the planar defects separating regions of

  15. Evaluation of Real-time Measurement Liver Tumor's Movement and SynchronyTM System's Accuracy of Radiosurgery using a Robot CyberKnife

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Gha Jung; Shim, Su Jung; Kim, Jeong Ho; Min, Chul Kee; Chung, Weon Kuu [Konyang University College of Medicine, Daejeon (Korea, Republic of)

    2008-12-15

    This study aimed to quantitatively measure the movement of tumors in real-time and evaluate the treatment accuracy, during the treatment of a liver tumor patient, who underwent radiosurgery with a Synchrony Respiratory motion tracking system of a robot CyberKnife. Materials and Methods: The study subjects included 24 liver tumor patients who underwent CyberKnife treatment, which included 64 times of treatment with the Synchrony Respiratory motion tracking system (SynchronyTM). The treatment involved inserting 4 to 6 acupuncture needles into the vicinity of the liver tumor in all the patients using ultrasonography as a guide. A treatment plan was set up using the CT images for treatment planning uses. The position of the acupuncture needle was identified for every treatment time by Digitally Reconstructed Radiography (DRR) prepared at the time of treatment planning and X-ray images photographed in real-time. Subsequent results were stored through a Motion Tracking System (MTS) using the Mtsmain.log treatment file. In this way, movement of the tumor was measured. Besides, the accuracy of radiosurgery using CyberKnife was evaluated by the correlation errors between the real-time positions of the acupuncture needles and the predicted coordinates. Results: The maximum and the average translational movement of the liver tumor were measured 23.5 mm and 13.9{+-}5.5 mm, respectively from the superior to the inferior direction, 3.9 mm and 1.9{+-}0.9 mm, respectively from left to right, and 8.3 mm and 4.9{+-}1.9 mm, respectively from the anterior to the posterior direction. The maximum and the average rotational movement of the liver tumor were measured to be 3.3o and 2.6{+-}1.3o, respectively for X (Left-Right) axis rotation, 4.8o and 2.3{+-}1.0o, respectively for Y (Cranio-Caudal) axis rotation, 3.9o and 2.8{+-}1.1o, respectively for Z (Anterior-Posterior) axis rotation. In addition, the average correlation error, which represents the treatment's accuracy was 1

  16. Hydrodynamics of ultra-relativistic bubble walls

    Directory of Open Access Journals (Sweden)

    Leonardo Leitao

    2016-04-01

    Full Text Available In cosmological first-order phase transitions, gravitational waves are generated by the collisions of bubble walls and by the bulk motions caused in the fluid. A sizeable signal may result from fast-moving walls. In this work we study the hydrodynamics associated to the fastest propagation modes, namely, ultra-relativistic detonations and runaway solutions. We compute the energy injected by the phase transition into the fluid and the energy which accumulates in the bubble walls. We provide analytic approximations and fits as functions of the net force acting on the wall, which can be readily evaluated for specific models. We also study the back-reaction of hydrodynamics on the wall motion, and we discuss the extrapolation of the friction force away from the ultra-relativistic limit. We use these results to estimate the gravitational wave signal from detonations and runaway walls.

  17. Domain Wall Propagation through Spin Wave Emission

    NARCIS (Netherlands)

    Wang, X.S.; Yan, P.; Shen, Y.H.; Bauer, G.E.W.; Wang, X.R.

    2012-01-01

    We theoretically study field-induced domain wall motion in an electrically insulating ferromagnet with hard- and easy-axis anisotropies. Domain walls can propagate along a dissipationless wire through spin wave emission locked into the known soliton velocity at low fields. In the presence of damping

  18. Wall Turbulence.

    Science.gov (United States)

    Hanratty, Thomas J.

    1980-01-01

    This paper gives an account of research on the structure of turbulence close to a solid boundary. Included is a method to study the flow close to the wall of a pipe without interferring with it. (Author/JN)

  19. Speaker detection for conversational robots using synchrony between audio and video

    NARCIS (Netherlands)

    A. Noulas; G. Englebienne; B. Terwijn; B. Kröse

    2010-01-01

    This paper compares different methods for detecting the speaking person when multiple persons are interacting with a robot. We evaluate the state-of-the-art speaker detection methods on the iCat robot. These methods use the synchrony between audio and video to locate the most probable speaker. We co

  20. An Association between Auditory-Visual Synchrony Processing and Reading Comprehension: Behavioral and Electrophysiological Evidence.

    Science.gov (United States)

    Mossbridge, Julia; Zweig, Jacob; Grabowecky, Marcia; Suzuki, Satoru

    2017-03-01

    The perceptual system integrates synchronized auditory-visual signals in part to promote individuation of objects in cluttered environments. The processing of auditory-visual synchrony may more generally contribute to cognition by synchronizing internally generated multimodal signals. Reading is a prime example because the ability to synchronize internal phonological and/or lexical processing with visual orthographic processing may facilitate encoding of words and meanings. Consistent with this possibility, developmental and clinical research has suggested a link between reading performance and the ability to compare visual spatial/temporal patterns with auditory temporal patterns. Here, we provide converging behavioral and electrophysiological evidence suggesting that greater behavioral ability to judge auditory-visual synchrony (Experiment 1) and greater sensitivity of an electrophysiological marker of auditory-visual synchrony processing (Experiment 2) both predict superior reading comprehension performance, accounting for 16% and 25% of the variance, respectively. These results support the idea that the mechanisms that detect auditory-visual synchrony contribute to reading comprehension.

  1. Functioning within a relationship : Mother-infant synchrony and infant sleep

    NARCIS (Netherlands)

    de Graag, Jolien A.; Cox, Ralf F. A.; Hasselman, Fred; Jansen, Jarno; de Weerth, Carolina

    2012-01-01

    The aim of this study was to investigate the coupling of the biological system of infant sleep and the social system of mother-infant synchrony. Before birth and shortly after birth the systems appear to be connected, but it is unclear whether this remains the case over time. This study therefore ex

  2. Phenology of forest caterpillars and their host trees: The importance of synchrony

    NARCIS (Netherlands)

    Van Asch, M.; Visser, M.E.

    2007-01-01

    For many leaf-feeding herbivores, synchrony in phenology with their host plant is crucial as development outside a narrow phenological time window has severe fitness consequences. In this review, we link mechanisms, adaptation, and population dynamics within a single conceptual framework, needed for

  3. Timing and synchrony of births in bighorn sheep: implications for reintroduction and conservation

    Science.gov (United States)

    Whiting, Jericho C.; Olson, Daniel D.; Shannon, Justin M.; Bowyer, R. Terry; Klaver, Robert W.; Flinders, Jerran T.

    2012-01-01

    Context: Timing (mean birthdate) and synchrony (variance around that date) of births can influence survival of young and growth in ungulate populations. Some restored populations of ungulates may not adjust these life-history characteristics to environments of release sites until several years after release, which may influence success of reintroductions.

  4. Sharing the Now in the Social Present: Duration of Nonverbal Synchrony Is Linked With Personality.

    Science.gov (United States)

    Tschacher, Wolfgang; Ramseyer, Fabian; Koole, Sander L

    2016-12-15

    The social present is a novel descriptor of dyadic nowness and social sharing, extending research on individual nowness (James's [1890] specious present) to the interpersonal and intersubjective domain. We wished to connect this descriptor to personality attributes. We define the social present by the duration of significant nonverbal synchrony, based on the phenomenon of movement synchrony that generally emerges in social interactions. It is thus an implicit and objective measure that can be implemented by automated video analyses. In this study, 168 healthy participants were invited to verbal conversations in same-sex dyads. We analyzed the associations of the social present with personality attributes and interaction types (competition, cooperation, fun task). The average duration of the social present was 6.0 seconds, highest in competitive interactions and in male-male dyads. People with higher Openness to Experience, higher avoidant attachment, and lower narcissistic interpersonal styles showed extended social present in their interactions. The concept of the social present extends personality attributes to the interpersonal domain and to intersubjectivity. The social present may be computed based on movement synchrony but also prosodic or physiological synchronies. We foresee implications for health-related interactions such as psychotherapy, where therapeutic presence is an essential property of alliance. © 2016 Wiley Periodicals, Inc.

  5. Physical and Relational Aggression in Young Children: The Role of Mother-Child Interactional Synchrony

    Science.gov (United States)

    Ambrose, Holly N.; Menna, Rosanne

    2013-01-01

    This study examined the relationships between the quality of parent-child interactions, specifically interactional synchrony (IS), and physical and relational aggression in young children. Seventy-three children (3-6 years; 44 males, 29 females) and their mothers participated in this study. The children's level of aggression was assessed through…

  6. Selective Attention to a Talker's Mouth in Infancy: Role of Audiovisual Temporal Synchrony and Linguistic Experience

    Science.gov (United States)

    Hillairet de Boisferon, Anne; Tift, Amy H.; Minar, Nicholas J.; Lewkowicz, David J.

    2017-01-01

    Previous studies have found that infants shift their attention from the eyes to the mouth of a talker when they enter the canonical babbling phase after 6 months of age. Here, we investigated whether this increased attentional focus on the mouth is mediated by audio-visual synchrony and linguistic experience. To do so, we tracked eye gaze in 4-,…

  7. Interpersonal synchrony enhanced through 20 Hz phase-coupled dual brain stimulation.

    Science.gov (United States)

    Novembre, Giacomo; Knoblich, Günther; Dunne, Laura; Keller, Peter E

    2017-01-24

    Synchronous movement is a key component of social behaviour in several species including humans. Recent theories have suggested a link between interpersonal synchrony of brain oscillations and interpersonal movement synchrony. The present study investigated this link. Using transcranial alternating current stimulation (tACS) applied over the left motor cortex, we induced beta band (20 Hz) oscillations in pairs of individuals who both performed a finger-tapping task with the right hand. In-phase or anti-phase oscillations were delivered during a preparatory period prior to movement and while the tapping task was performed. In-phase 20 Hz stimulation enhanced interpersonal movement synchrony, compared to anti-phase or sham stimulation, particularly for the initial taps following the preparatory period. This was confirmed in an analysis comparing real vs. pseudo pair surrogate data. No enhancement was observed for stimulation frequencies of 2 Hz (matching the target movement frequency) or 10 Hz (alpha band). Thus, phase-coupling of beta band neural oscillations across two individuals' (resting) motor cortices supports the interpersonal alignment of sensorimotor processes that regulate rhythmic action initiation, thereby facilitating the establishment of synchronous movement. Phase-locked dual brain stimulation provides a promising method to study causal effects of interpersonal brain synchrony on social, sensorimotor and cognitive processes.

  8. Phenology of forest caterpillars and their host trees: The importance of synchrony

    NARCIS (Netherlands)

    Van Asch, M.; Visser, M.E.

    2007-01-01

    For many leaf-feeding herbivores, synchrony in phenology with their host plant is crucial as development outside a narrow phenological time window has severe fitness consequences. In this review, we link mechanisms, adaptation, and population dynamics within a single conceptual framework, needed for

  9. Synchrony and Specificity in the Maternal and the Paternal Brain: Relations to Oxytocin and Vasopressin

    Science.gov (United States)

    Atzil, Shir; Hendler, Talma; Zagoory-Sharon, Orna; Winetraub, Yonatan; Feldman, Ruth

    2012-01-01

    Objective: Research on the neurobiology of parenting has defined "biobehavioral synchrony," the coordination of biological and behavioral responses between parent and child, as a central process underpinning mammalian bond formation. Bi-parental rearing, typically observed in monogamous species, is similarly thought to draw on mechanisms of…

  10. Synchrony in the snowshoe hare cycle in Northwestern North America, 1970-2012

    Science.gov (United States)

    C.J. Krebs; K. Kielland; J.P Bryant; M. O' Donoghue; F. Doyle; C. McIntyre; D. DiFolco; N. Berg; S. Carriere; R. Boonstra; S. Boutin; A. J. Kenney; D. G. Reid; K. Bodony; J. Putera; H. K. Timm; T. Burke.

    2013-01-01

    Snowshoe hares (Lepus americanus Erxleben, 1777) fluctuate in 9–10 year cycles throughout much of their North American range. Regional synchrony has been assumed to be the rule for these cycles, so that hare populations in virtually all of northwestern North America have been assumed to be in phase. We gathered qualitative and quantitative data on...

  11. Don't worry, be (moderately) happy: Mothers' anxiety and positivity during pregnancy independently predict lower mother-infant synchrony.

    Science.gov (United States)

    Moore, Ginger A; Quigley, Kelsey M; Voegtline, Kristin M; DiPietro, Janet A

    2016-02-01

    Maternal positivity and mother-infant synchrony have been linked, independently, to beneficial infant outcomes; however, research that has examined relations between the two has found that higher positivity is associated with lower synchrony. Methodological issues may inform this counter-intuitive association and clinical theory supports its validity. This study examined the theory that heightened positivity associated with anxiety is a way of avoiding negative emotion and contributes to lower synchrony because it interferes with appropriate responding to infant cues. We examined mothers' (N=75) self-reported anxiety and verbal expression of positivity during pregnancy in relation to mother-infant synchrony at 6 months post-partum. Verbal positivity was assessed using linguistic analysis of interviews about pregnancy experiences. Mother and infant affect and gaze were coded during interaction and synchrony was computed as the correlation between mother and infant behaviors. Higher verbal positivity and anxiety during pregnancy independently predicted lower mother-infant synchrony, suggesting distinct pathways to the same degree of synchrony with potentially different consequences for infant development.

  12. Oscillatory synchrony between head direction cells recorded bilaterally in the anterodorsal thalamic nuclei.

    Science.gov (United States)

    Butler, William N; Taube, Jeffrey Steven

    2017-03-01

    The head direction (HD) circuit is a complex, interconnected network of brain regions ranging from the brainstem to the cortex. Recent work found that HD cells co-recorded ipsilaterally in the anterodorsal nucleus (ADN) of the thalamus displayed coordinated firing patterns. A high frequency oscillation pattern (130-160 Hz) was visible in the cross-correlograms of these HD cell pairs. Spectral analysis further found that the power of this oscillation was greatest at 0 ms and decreased at greater lags, and demonstrated that there was greater synchrony between HD cells with similar tunings. Here, we demonstrate that the same high frequency synchrony exists in HD cell pairs recorded contralaterally from one another in the bilateral ADN. When we examined the cross-correlograms of HD cells that were co-recorded bilaterally we observed the same high frequency (~150-200 Hz) oscillatory relationship. The strength of this synchrony was similar to the synchrony seen in ipsilateral HD cell pairs, and the degree of synchrony in each cross-correlogram was dependent on the difference in tuning between the two cells. Additionally, the frequency rate of this oscillation appeared to be independent of the firing rates of the two cross-correlated cells. Taken together, these results imply that the left and right thalamic HD network are functionally related, despite an absence of direct anatomical projections. However, anatomical tracing has found that each of the lateral mammillary nuclei (LMN) project bilaterally to both of the ADN, suggesting the LMN may be responsible for the functional connectivity observed between the two ADN.

  13. Role of across‐muscle motor unit synchrony for the coordination of forces

    Science.gov (United States)

    Santello, Marco; Fuglevand, Andrew J.

    2007-01-01

    Evidence from five‐digit grasping studies indicates that grip forces exerted by pairs of digits tend to be synchronized. It has been suggested that motor unit synchronization might be a mechanism responsible for constraining the temporal relationships between grip forces. To evaluate this possibility and quantify the effect of motor unit synchrony on force relationships, we used a motor unit model to simulate force produced by two muscles using three physiological levels of motor unit synchrony across the two muscles. In one condition, motor units in the two muscles discharged independently of one another. In the other two conditions, the timing of randomly selected motor unit discharges in one muscle was adjusted to impose low or high levels of synchrony with motor units in the other muscle. Fast Fourier transform analysis was performed to compute the phase differences between forces from 0.5 to 17 Hz. We used circular statistics to assess whether the phase differences at each frequency were randomly or non‐randomly distributed (Rayleigh test). The mean phase difference was then computed on the non‐random distributions. We found that the number of significant phase‐difference distributions increased markedly with increasing synchronization strength from 18% for no synchrony to 65% and 82% for modest and strong synchrony conditions, respectively. Importantly, most of the mean angles clustered at very small phase difference values (∼0 to 10°), indicating a strong tendency for forces to be exerted in a synchronous fashion. These results suggest that motor unit synchronization could play a significant functional role in the coordination of grip forces. PMID:15558252

  14. Dissociable effects of dopamine on neuronal firing rate and synchrony in the dorsal striatum

    Directory of Open Access Journals (Sweden)

    John M Burkhardt

    2009-10-01

    Full Text Available Previous studies showed that dopamine depletion leads to both changes in firing rate and in neuronal synchrony in the basal ganglia. Since dopamine D1 and D2 receptors are preferentially expressed in striatonigral and striatopallidal medium spiny neurons, respectively, we investigated the relative contribution of lack of D1 and/or D2-type receptor activation to the changes in striatal firing rate and synchrony observed after dopamine depletion. Similar to what was observed after dopamine depletion, co-administration of D1 and D2 antagonists to mice chronically implanted with multielectrode arrays in the striatum caused significant changes in firing rate, power of the local field potential (LFP oscillations, and synchrony measured by the entrainment of neurons to striatal local field potentials. However, although blockade of either D1 or D2 type receptors produced similarly severe akinesia, the effects on neural activity differed. Blockade of D2 receptors affected the firing rate of medium spiny neurons and the power of the LFP oscillations substantially, but it did not affect synchrony to the same extent. In contrast, D1 blockade affected synchrony dramatically, but had less substantial effects on firing rate and LFP power. Furthermore, there was no consistent relation between neurons changing firing rate and changing LFP entrainment after dopamine blockade. Our results suggest that the changes in rate and entrainment to the LFP observed in medium spiny neurons after dopamine depletion are somewhat dissociable, and that lack of D1- or D2-type receptor activation can exert independent yet interactive pathological effects during the progression of Parkinson’s disease.

  15. 瓜蒌薤白半夏汤对不稳定性心绞痛心脏室壁运动的影响%The effects of gualouxiebaibanxia decoction on the cardiac ventricular wall motion abnormalities in unstable angina pectoris

    Institute of Scientific and Technical Information of China (English)

    林培森

    2012-01-01

    目的观察瓜蒌薤白半夏汤对不稳定性心绞痛(UAP)心脏室壁运动异常的疗效.方法将120例经心彩超证实有心脏室壁运动异常的UAP患者随机分为治疗组与对照组,每组各60例.对照组采用常规的西药治疗,治疗组在西药治疗基础上加用瓜蒌薤白半夏汤,疗程均为1个月.结果与对照组比较,治疗组在缓解心绞痛发作方面的有效率优于对照组(93.3% VS 83.3%),治疗组在胸痹证候改善方面的有效率也优于对照组(86.6% VS 73.3%),治疗组在改善心电图方面的有效率也优于对照组(81.6% VS 63.3%),治疗组在改善心脏室壁运动异常的有效率也优于对照组(78.3% VS 65%),差异均有显著性意义(P<0.05).结论应用瓜蒌薤白半夏汤治疗UAP疗效确切,可明显改善心电图及心脏室壁运动异常.%Objective: To observe the curative effects of gualouxiebaibanxia decoction on the cardiac ventricular wall motion abnormalities in unstable angina pectoris. Methods: 120 cases of patients with ustable angina pectoris and cardiac ventricular wall motion abnormalities were randomly divided into two groups, treatment group and control group, 60 cases in each group. Control group was treated with western medicine and treatment group with gualouxiebaibanxia decoction and western medicine for one month. Results: Compared with the control group, the efficacy of treatment group was better in relieving angina pectoris(81.6% VS 63.3%), improving chest syndrome(86.6% VS 73.3%), improving electrocardiograph (81.6% VS 63.3%), and improving cardiac ventricular wall motion abnormalities(78.3% VS 65%). The differences were significant (P <0.05). Conclusion: It is effective that treating unstable angina pectoris with gualouxiebaibanxia decoction, which can significantly improve electrocardiograph and cardiac ventricular wall motion abnormalities.

  16. Influence of Visual Motion on Tactile Motion Perception

    Science.gov (United States)

    Bensmaïa, S. J.; Killebrew, J. H.; Craig, J. C.

    2007-01-01

    Subjects were presented with pairs of tactile drifting sinusoids and made speed discrimination judgments. On some trials, a visual drifting sinusoid, which subjects were instructed to ignore, was presented simultaneously with one of the two tactile stimuli. When the visual and tactile gratings drifted in the same direction (i.e., from left to right), the visual distractors were found to increase the perceived speed of the tactile gratings. The effect of the visual distractors was proportional to their temporal frequency but not to their perceived speed. When the visual and tactile gratings drifted in opposite directions, the distracting effect of the visual distractors was either substantially reduced or, in some cases, reversed (i.e., the distractors slowed the perceived speed of the tactile gratings). This result suggests that the observed visual-tactile interaction is dependent on motion and not simply on the oscillations inherent in drifting sinusoids. Finally, we find that disrupting the temporal synchrony between the visual and tactile stimuli eliminates the distracting effect of the visual stimulus. We interpret this latter finding as evidence that the observed visual-tactile interaction operates at the sensory level and does not simply reflect a response bias. PMID:16723415

  17. Wall Art

    Science.gov (United States)

    McGinley, Connie Q.

    2004-01-01

    The author of this article, an art teacher at Monarch High School in Louisville, Colorado, describes how her experience teaching in a new school presented an exciting visual challenge for an art teacher--monotonous brick walls just waiting for decoration. This school experienced only minimal instances of graffiti, but as an art teacher, she did…

  18. A joint behavioral and emotive analysis of synchrony in music therapy of children with autism spectrum disorders

    Directory of Open Access Journals (Sweden)

    Paola Venuti

    2016-12-01

    Full Text Available Background Synchrony is an essential component of interactive exchanges. In mother-infant interaction, synchrony underlies reciprocity and emotive regulation. A severe lack of synchrony is indeed a core issue within the communication and interaction deficit that characterizes autism spectrum disorders (ASD in accordance with the DSM-5 classification. Based on emerging evidence that music therapy can improve the communication and regulation ability in children with ASD, we aim to verify quantitatively whether: 1 children with ASD improve synchrony with their therapist during music therapy sessions, and 2 this ability persists in different structured contexts. Participants and procedure Twenty-five children, aged from 4 to 6 years (M = 57.80, SD = 16.70, with an autistic disorder diagnosis based on DSM IV-TR and the Autism Diagnostic Observation Schedule (ADOS, participated in the study. An observational tool for coding behaviors and emotive states of synchrony (Child Behavioral and Emotional status Code [CBEC] and Adult Behavioral and Emotional status Code [ABEC] was applied in video recorded sessions of improvisational music therapy (IMT for the subject-therapist pair. For each subject, we considered the 20 central minutes of the first, tenth and twentieth session of IMT. To verify the persistence of effect in a different context with a different adult, we administered and coded the interactive ADOS section (anticipation of a routine with objects applied after session 20 of therapy. Results During the IMT cycle, the amount of synchronic activity increases, with a significant difference from Session 1 to Session 20 in behavioral synchrony and emotional attunement. Also, the increase of synchrony is confirmed at the end of the therapy cycle as measured by an interactive ADOS section. Conclusions Synchrony is an effective indicator of efficacy for music therapy in children with ASD, in particular to evaluate the expansion of positive emotive

  19. Infant negative reactivity defines the effects of parent-child synchrony on physiological and behavioral regulation of social stress.

    Science.gov (United States)

    Pratt, Maayan; Singer, Magi; Kanat-Maymon, Yaniv; Feldman, Ruth

    2015-11-01

    How infants shape their own development has puzzled developmentalists for decades. Recent models suggest that infant dispositions, particularly negative reactivity and regulation, affect outcome by determining the extent of parental effects. Here, we used a microanalytic experimental approach and proposed that infants with varying levels of negative reactivity will be differentially impacted by parent-infant synchrony in predicting physiological and behavioral regulation of increasing social stress during an experimental paradigm. One hundred and twenty-two mother-infant dyads (4-6 months) were observed in the face-to-face still face (SF) paradigm and randomly assigned to three experimental conditions: SF with touch, standard SF, and SF with arms' restraint. Mother-infant synchrony and infant negative reactivity were observed at baseline, and three mechanisms of behavior regulation were microcoded; distress, disengagement, and social regulation. Respiratory sinus arrhythmia baseline, reactivity, and recovery were quantified. Structural equation modeling provided support for our hypothesis. For physiological regulation, infants high in negative reactivity receiving high mother-infant synchrony showed greater vagal withdrawal, which in turn predicted comparable levels of vagal recovery to that of nonreactive infants. In behavioral regulation, only infants low in negative reactivity who received high synchrony were able to regulate stress by employing social engagement cues during the SF phase. Distress was reduced only among calm infants to highly synchronous mothers, and disengagement was lowest among highly reactive infants experiencing high mother-infant synchrony. Findings chart two pathways by which synchrony may bolster regulation in infants of high and low reactivity. Among low reactive infants, synchrony builds a social repertoire for handling interpersonal stress, whereas in highly reactive infants, it constructs a platform for repeated reparation of

  20. ON WALL SHEAR STRESS OF ARTERY

    Institute of Scientific and Technical Information of China (English)

    Liu Zhao-rong; Liu Bao-yu; Qin Kai-rong

    2003-01-01

    In this paper, a method was proposed that the wall shear stress of artery could be determined by measuring the centerline axial velocity and radial motion of arterial wall simultaneously.The method is simple in application and can get higher precision when it is used to determine the shear stress of arterial wall in vivo.As an example, the shear stress distribution in periodic oscillatory flow of human carotid was calculated and discussed.The computed results show that the shear stress distribution at any given instant is almost uniform and will be zero at the centerline and tends to maximum at the vessel wall.

  1. Great attractor really a great wall

    Energy Technology Data Exchange (ETDEWEB)

    Stebbins, A.; Turner, M.S.

    1988-11-01

    Some of the cosmological consequences are discussed of a late time phase transition which produces light domain walls. The observed peculiar velocity field of the Universe and the observed isotropy of the microwave background radiation severely constrain the wall surface density in such a scenario. The most interesting consequence of such a phase transition is the possibility that the local, coherent streaming motion reported by the Seven Samurai could be explained by the repulsive effect of a relic domain wall with the Hubble volume (the Great Wall).

  2. Characterising intra- and inter-intrinsic network synchrony in combat-related post-traumatic stress disorder.

    Science.gov (United States)

    Dunkley, Benjamin T; Doesburg, Sam M; Jetly, Rakesh; Sedge, Paul A; Pang, Elizabeth W; Taylor, Margot J

    2015-11-30

    Soldiers with post-traumatic stress disorder (PTSD) exhibit elevated gamma-band synchrony in left fronto-temporal cortex, and connectivity measures in these regions correlate with comorbidities and PTSD severity, which suggests increased gamma synchrony is related to symptomology. However, little is known about the role of intrinsic, phase-synchronised networks in the disorder. Using magnetoencephalography (MEG), we characterised spectral connectivity in the default-mode, salience, visual, and attention networks during resting-state in a PTSD population and a trauma-exposed control group. Intrinsic network connectivity was examined in canonical frequency bands. We observed increased inter-network synchronisation in the PTSD group compared with controls in the gamma (30-80 Hz) and high-gamma range (80-150 Hz). Analyses of connectivity and symptomology revealed that PTSD severity was positively associated with beta synchrony in the ventral-attention-to-salience networks, and gamma synchrony within the salience network, but also negatively correlated with beta synchrony within the visual network. These novel results show that frequency-specific, network-level atypicalities may reflect trauma-related alterations of ongoing functional connectivity, and correlations of beta synchrony in attentional-to-salience and visual networks with PTSD severity suggest complicated network interactions mediate symptoms. These results contribute to accumulating evidence that PTSD is a complicated network-based disorder expressed as altered neural interactions.

  3. An eight month randomized controlled exercise intervention alters resting state synchrony in overweight children.

    Science.gov (United States)

    Krafft, C E; Pierce, J E; Schwarz, N F; Chi, L; Weinberger, A L; Schaeffer, D J; Rodrigue, A L; Camchong, J; Allison, J D; Yanasak, N E; Liu, T; Davis, C L; McDowell, J E

    2014-01-03

    Children with low aerobic fitness have altered brain function compared to higher-fit children. This study examined the effect of an 8-month exercise intervention on resting state synchrony. Twenty-two sedentary, overweight (body mass index ≥85th percentile) children 8-11 years old were randomly assigned to one of two after-school programs: aerobic exercise (n=13) or sedentary attention control (n=9). Before and after the 8-month programs, all subjects participated in resting state functional magnetic resonance imaging scans. Independent components analysis identified several networks, with four chosen for between-group analysis: salience, default mode, cognitive control, and motor networks. The default mode, cognitive control, and motor networks showed more spatial refinement over time in the exercise group compared to controls. The motor network showed increased synchrony in the exercise group with the right medial frontal gyrus compared to controls. Exercise behavior may enhance brain development in children.

  4. The "conscious pilot"-dendritic synchrony moves through the brain to mediate consciousness.

    Science.gov (United States)

    Hameroff, Stuart

    2010-01-01

    Cognitive brain functions including sensory processing and control of behavior are understood as "neurocomputation" in axonal-dendritic synaptic networks of "integrate-and-fire" neurons. Cognitive neurocomputation with consciousness is accompanied by 30- to 90-Hz gamma synchrony electroencephalography (EEG), and non-conscious neurocomputation is not. Gamma synchrony EEG derives largely from neuronal groups linked by dendritic-dendritic gap junctions, forming transient syncytia ("dendritic webs") in input/integration layers oriented sideways to axonal-dendritic neurocomputational flow. As gap junctions open and close, a gamma-synchronized dendritic web can rapidly change topology and move through the brain as a spatiotemporal envelope performing collective integration and volitional choices correlating with consciousness. The "conscious pilot" is a metaphorical description for a mobile gamma-synchronized dendritic web as vehicle for a conscious agent/pilot which experiences and assumes control of otherwise non-conscious auto-pilot neurocomputation.

  5. High reproductive synchrony of Acropora (Anthozoa: Scleractinia) in the Gulf of Aqaba, Red Sea.

    Science.gov (United States)

    Bouwmeester, Jessica; Berumen, Michael L

    2015-01-01

    Coral spawning in the northern Gulf of Aqaba has been reported to be asynchronous, making it almost unique when compared to other regions in the world. Here, we document the reproductive condition of Acropora corals in early June 2014 in Dahab, in the Gulf of Aqaba, 125 km south of previous studies conducted in Eilat, Israel. Seventy-eight percent of Acropora colonies from 14 species had mature eggs, indicating that most colonies will spawn on or around the June full moon, with a very high probability of multi-species synchronous spawning. Given the proximity to Eilat, we predict that a comparable sampling protocol would detect similar levels of reproductive synchrony throughout the Gulf of Aqaba consistent with the hypothesis that high levels of spawning synchrony are a feature of all speciose coral assemblages.

  6. Incorporating oximeter analyses to investigate synchronies in heart rate while teaching and learning about race

    Science.gov (United States)

    Amat, Arnau; Zapata, Corinna; Alexakos, Konstantinos; Pride, Leah D.; Paylor-Smith, Christian; Hernandez, Matthew

    2016-09-01

    In this paper, we look closely at two events selected through event-oriented inquiry that were part of a classroom presentation on race. The first event was a provocative discussion about Mark Twain's ( Pudd'nhead Wilson, Harper, New York, 1899) and passing for being White. The other was a discussion on the use of the N-word. Grounded in authentic inquiry, we use ethnographic narrative, cogenerative dialogues, and video and oximeter data analyses as part of a multi-ontological approach for studying emotions. Statistical analysis of oximeter data shows statistically significant heart rate synchrony among two of the coteachers during their presentations, providing evidence of emotional synchrony, resonance, and social and emotional contagion.

  7. A universal order parameter for synchrony in networks of limit cycle oscillators

    Science.gov (United States)

    Schröder, Malte; Timme, Marc; Witthaut, Dirk

    2017-07-01

    We analyze the properties of order parameters measuring synchronization and phase locking in complex oscillator networks. First, we review network order parameters previously introduced and reveal several shortcomings: none of the introduced order parameters capture all transitions from incoherence over phase locking to full synchrony for arbitrary, finite networks. We then introduce an alternative, universal order parameter that accurately tracks the degree of partial phase locking and synchronization, adapting the traditional definition to account for the network topology and its influence on the phase coherence of the oscillators. We rigorously prove that this order parameter is strictly monotonously increasing with the coupling strength in the phase locked state, directly reflecting the dynamic stability of the network. Furthermore, it indicates the onset of full phase locking by a diverging slope at the critical coupling strength. The order parameter may find applications across systems where different types of synchrony are possible, including biological networks and power grids.

  8. Detecting dynamical interdependence and generalized synchrony through mutual prediction in a neural ensemble

    Science.gov (United States)

    Schiff, Steven J.; So, Paul; Chang, Taeun; Burke, Robert E.; Sauer, Tim

    1996-12-01

    A method to characterize dynamical interdependence among nonlinear systems is derived based on mutual nonlinear prediction. Systems with nonlinear correlation will show mutual nonlinear prediction when standard analysis with linear cross correlation might fail. Mutual nonlinear prediction also provides information on the directionality of the coupling between systems. Furthermore, the existence of bidirectional mutual nonlinear prediction in unidirectionally coupled systems implies generalized synchrony. Numerical examples studied include three classes of unidirectionally coupled systems: systems with identical parameters, nonidentical parameters, and stochastic driving of a nonlinear system. This technique is then applied to the activity of motoneurons within a spinal cord motoneuron pool. The interrelationships examined include single neuron unit firing, the total number of neurons discharging at one time as measured by the integrated monosynaptic reflex, and intracellular measurements of integrated excitatory postsynaptic potentials (EPSP's). Dynamical interdependence, perhaps generalized synchrony, was identified in this neuronal network between simultaneous single unit firings, between units and the population, and between units and intracellular EPSP's.

  9. High reproductive synchrony of Acropora (Anthozoa: Scleractinia) in the Gulf of Aqaba, Red Sea

    KAUST Repository

    Bouwmeester, Jessica

    2015-01-05

    Coral spawning in the northern Gulf of Aqaba has been reported to be asynchronous, making it almost unique when compared to other regions in the world. Here, we document the reproductive condition of Acropora corals in early June 2014 in Dahab, in the Gulf of Aqaba, 125 km south of previous studies conducted in Eilat, Israel. Seventy-eight percent of Acropora colonies from 14 species had mature eggs, indicating that most colonies will spawn on or around the June full moon, with a very high probability of multi-species synchronous spawning. Given the proximity to Eilat, we predict that a comparable sampling protocol would detect similar levels of reproductive synchrony throughout the Gulf of Aqaba consistent with the hypothesis that high levels of spawning synchrony are a feature of all speciose coral assemblages.

  10. True and Perceived Synchrony are Preferentially Associated With Particular Sensory Pairings

    Science.gov (United States)

    Noel, Jean-Paul; Wallace, Mark T.; Orchard-Mills, Emily; Alais, David; Van der Burg, Erik

    2015-01-01

    Perception and behavior are fundamentally shaped by the integration of different sensory modalities into unique multisensory representations, a process governed by spatio-temporal correspondence. Prior work has characterized temporal perception using the point in time at which subjects are most likely to judge multisensory stimuli to be simultaneous (PSS) and the temporal binding window (TBW) over which participants are likely to do so. Here we examine the relationship between the PSS and the TBW within and between individuals, and within and between three sensory combinations: audiovisual, audiotactile and visuotactile. We demonstrate that TBWs correlate within individuals and across multisensory pairings, but PSSs do not. Further, we reveal that while the audiotactile and audiovisual pairings show tightly related TBWs, they also exhibit a differential relationship with respect to true and perceived multisensory synchrony. Thus, audiotactile and audiovisual temporal processing share mechanistic features yet are respectively functionally linked to objective and subjective synchrony. PMID:26621493

  11. Time-resolved and time-scale adaptive measures of spike train synchrony

    CERN Document Server

    Kreuz, Thomas; Greschner, Martin; Andrzejak, Ralph G

    2010-01-01

    A wide variety of approaches to estimate the degree of synchrony between two or more spike trains have been proposed. One of the most recent methods is the ISI-distance which extracts information from the interspike intervals (ISIs) by evaluating the ratio of the instantaneous firing rates. In contrast to most previously proposed measures it is parameter free and time-scale independent. However, it is not well suited to track changes in synchrony that are based on spike coincidences. Here we propose the SPIKE-distance, a complementary measure which is sensitive to spike coincidences but still shares the fundamental advantages of the ISI-distance. In particular, it is easy to visualize in a time-resolved manner and can be extended to a method that is also applicable to larger sets of spike trains. We show the merit of the SPIKE-distance using both simulated and real data.

  12. Time-resolved and time-scale adaptive measures of spike train synchrony.

    Science.gov (United States)

    Kreuz, Thomas; Chicharro, Daniel; Greschner, Martin; Andrzejak, Ralph G

    2011-01-30

    A wide variety of approaches to estimate the degree of synchrony between two or more spike trains have been proposed. One of the most recent methods is the ISI-distance which extracts information from the interspike intervals (ISIs) by evaluating the ratio of the instantaneous firing rates. In contrast to most previously proposed measures it is parameter free and time-scale independent. However, it is not well suited to track changes in synchrony that are based on spike coincidences. Here we propose the SPIKE-distance, a complementary measure which is sensitive to spike coincidences but still shares the fundamental advantages of the ISI-distance. In particular, it is easy to visualize in a time-resolved manner and can be extended to a method that is also applicable to larger sets of spike trains. We show the merit of the SPIKE-distance using both simulated and real data. Copyright © 2010 Elsevier B.V. All rights reserved.

  13. Reduction in Cortical Gamma Synchrony during Depolarized State of Slow Wave Activity in Mice

    Directory of Open Access Journals (Sweden)

    EUNJIN eHWANG

    2013-12-01

    Full Text Available EEG gamma band oscillations have been proposed to account for the neural synchronization crucial for perceptual integration. While increased gamma power and synchronization is generally observed during cognitive tasks performed during wake, several studies have additionally reported increased gamma power during sleep or anesthesia, raising questions about the characteristics of gamma oscillation during impaired consciousness and its role in conscious processing. Phase-amplitude modulation has been observed between slow wave activity (SWA, 0.5–4 Hz and gamma oscillations during ketamine/xylazine anesthesia or sleep, showing increased gamma activity corresponding to the depolarized (ON state of SWA. Here we divided gamma activity into its ON and OFF (hyperpolarized state components based on the phase of SWA induced by ketamine/xylazine anesthesia and compared their power and synchrony with wake state levels in mice. We further investigated the state-dependent changes in both gamma power and synchrony across primary motor and primary somatosensory cortical regions and their interconnected thalamic regions throughout anesthesia and recovery. As observed previously, gamma power was as high as during wake specifically during the ON state of SWA. However, the synchrony of this gamma activity between somatosensory-motor cortical regions was significantly reduced compared to the baseline wake state. In addition, the somatosensory-motor cortical synchrony of gamma oscillations was reduced and restored in an anesthetic state-dependent manner, reflecting the changing depth of anesthesia. Our results provide evidence that during anesthesia changes in long-range information integration between cortical regions might be more critical for changes in consciousness than changes in local gamma oscillatory power.

  14. Role of across‐muscle motor unit synchrony for the coordination of forces

    OpenAIRE

    Santello, Marco; Fuglevand, Andrew J.

    2004-01-01

    Evidence from five‐digit grasping studies indicates that grip forces exerted by pairs of digits tend to be synchronized. It has been suggested that motor unit synchronization might be a mechanism responsible for constraining the temporal relationships between grip forces. To evaluate this possibility and quantify the effect of motor unit synchrony on force relationships, we used a motor unit model to simulate force produced by two muscles using three physiological levels of motor unit synchro...

  15. Temporally increasing spatial synchrony of North American temperature and bird populations

    Science.gov (United States)

    Walter D. Koenig; Andrew M. Liebhold

    2016-01-01

    The ecological impacts of modern global climate change are detectable in a wide variety of phenomena, ranging from shifts in species ranges to changes in community composition and human disease dynamics. So far, however, little attention has been given to temporal changes in spatial synchrony—the coincident change in abundance or value across the landscape—despite the...

  16. CLIMBING WALL

    CERN Multimedia

    1999-01-01

    The FIRE AND RESCUE Group of TIS Commission informs that the climbing wall in the yard of the Fire-fighters Station, is intended for the sole use of the members of that service, and recalls that access to this installation is forbidden for safety reasons to all persons not belonging to the Service.CERN accepts no liability for damage or injury suffered as a result of failure to comply with this interdiction.TIS/DI

  17. Synchrony-desynchrony in the tripartite model of fear: Predicting treatment outcome in clinically phobic children.

    Science.gov (United States)

    Benoit Allen, Kristy; Allen, Ben; Austin, Kristin E; Waldron, Jonathan C; Ollendick, Thomas H

    2015-08-01

    The tripartite model of fear posits that the fear response entails three loosely coupled components: subjective distress, behavioral avoidance, and physiological arousal. The concept of synchrony vs. desynchrony describes the degree to which changes in the activation of these components vary together (synchrony), independently, or inversely (both forms of desynchrony) over time. The present study assessed synchrony-desynchrony and its relationship to treatment outcome in a sample of 98 children with specific phobias both prior to and 1 week after receiving one-session treatment, a 3 h cognitive-behavioral intervention. The results suggest an overall pattern of desynchronous change whereby youth improved on behavioral avoidance and subjective distress following treatment, but their level of cardiovascular reactivity remained stable. However, we found evidence that synchronous change on the behavioral avoidance and subjective distress components was related to better treatment outcome, whereas desynchronous change on these components was related to poorer treatment outcome. These findings suggest that a fuller understanding of the three response systems and their interrelations in phobic youth may assist us in the assessment and treatment of these disorders, potentially leading to a more person-centered approach and eventually to enhanced treatment outcomes. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Optimizing rTMS treatment of a balance disorder with EEG neural synchrony and functional connectivity.

    Science.gov (United States)

    Guofa Shou; Han Yuan; Urbano, Diamond; Yoon-Hee Cha; Lei Ding

    2016-08-01

    Repetitive transcranial magnetic stimulation (rTMS) has been increasingly used for its potential treatment effects across diverse mental disorders. However, the treatment effect is elusive and the rate of positive responders is not high, which make it in great demand of optimizing rTMS protocols to improve the treatment effects and the rate. In this regard, neural activity guided optimization has indicated great potential in several neuroimaging studies. In this paper, we present our ongoing work on optimizing rTMS treatment of a balance disorder, i.e., Mal de Debarquement syndrome (MdDS), by investigating treatment-related EEG neural synchrony and functional connectivity changes. Motivated by our previous pilot study of rTMS on MdDS, we firstly applied a bilateral dorsolateral prefrontal cortex (DLPFC) rTMS protocol to evaluate its efficacy and the treatment-related neural responses via an independent component analysis (ICA)-based framework. Thereafter, guided by identified EEG neural synchrony and functional connectivity patterns, we proposed three potential stimulation targets covering posterior nodes of the default mode network (DMN), and implemented a new rTMS protocol by stimulating the target with the great symptoms relief. The preliminary clinical response data has indicated that the new rTMS protocol significantly increase the rate of positive responders and the degrees of the improvement. The present study demonstrates that it is promising to integrate EEG neural synchrony and functional connectivity into the optimization of rTMS protocols for different mental disorders.

  19. Body Movement Synchrony in Psychotherapeutic Counseling: A Study Using the Video-Based Quantification Method

    Science.gov (United States)

    Nagaoka, Chika; Komori, Masashi

    Body movement synchrony (i. e. rhythmic synchronization between the body movements of interacting partners) has been described by subjective impressions of skilled counselors and has been considered to reflect the depth of the client-counselor relationship. This study analyzed temporal changes in body movement synchrony through a video analysis of client-counselor dialogues in counseling sessions. Four 50-minute psychotherapeutic counseling sessions were analyzed, including two negatively evaluated sessions (low evaluation groups) and two positively evaluated sessions (high evaluation groups). In addition, two 50-minute ordinary advice sessions between two high school teachers and the clients in the high rating group were analyzed. All sessions represent role-playing. The intensity of the participants' body movement was measured using a video-based system. Temporal change of body movement synchrony was analyzed using moving correlations of the intensity between the two time series. The results revealed (1) A consistent temporal pattern among the four counseling cases, though the moving correlation coefficients were higher for the high evaluation group than the low evaluation group and (2) Different temporal patterns for the counseling and advice sessions even when the clients were the same. These results were discussed from the perspective of the quality of client-counselor relationship.

  20. Temporal dynamics of musical emotions examined through intersubject synchrony of brain activity.

    Science.gov (United States)

    Trost, Wiebke; Frühholz, Sascha; Cochrane, Tom; Cojan, Yann; Vuilleumier, Patrik

    2015-12-01

    To study emotional reactions to music, it is important to consider the temporal dynamics of both affective responses and underlying brain activity. Here, we investigated emotions induced by music using functional magnetic resonance imaging (fMRI) with a data-driven approach based on intersubject correlations (ISC). This method allowed us to identify moments in the music that produced similar brain activity (i.e. synchrony) among listeners under relatively natural listening conditions. Continuous ratings of subjective pleasantness and arousal elicited by the music were also obtained for the music outside of the scanner. Our results reveal synchronous activations in left amygdala, left insula and right caudate nucleus that were associated with higher arousal, whereas positive valence ratings correlated with decreases in amygdala and caudate activity. Additional analyses showed that synchronous amygdala responses were driven by energy-related features in the music such as root mean square and dissonance, while synchrony in insula was additionally sensitive to acoustic event density. Intersubject synchrony also occurred in the left nucleus accumbens, a region critically implicated in reward processing. Our study demonstrates the feasibility and usefulness of an approach based on ISC to explore the temporal dynamics of music perception and emotion in naturalistic conditions.

  1. Rigid patterns of synchrony for equilibria and periodic cycles in network dynamics

    Science.gov (United States)

    Golubitsky, Martin; Stewart, Ian

    2016-09-01

    We survey general results relating patterns of synchrony to network topology, applying the formalism of coupled cell systems. We also discuss patterns of phase-locking for periodic states, where cells have identical waveforms but regularly spaced phases. We focus on rigid patterns, which are not changed by small perturbations of the differential equation. Symmetry is one mechanism that creates patterns of synchrony and phase-locking. In general networks, there is another: balanced colorings of the cells. A symmetric network may have anomalous patterns of synchrony and phase-locking that are not consequences of symmetry. We introduce basic notions on coupled cell networks and their associated systems of admissible differential equations. Periodic states also possess spatio-temporal symmetries, leading to phase relations; these are classified by the H/K theorem and its analog for general networks. Systematic general methods for computing the stability of synchronous states exist for symmetric networks, but stability in general networks requires methods adapted to special classes of model equations.

  2. Patterns of synchrony for feed-forward and auto-regulation feed-forward neural networks.

    Science.gov (United States)

    Aguiar, Manuela A D; Dias, Ana Paula S; Ferreira, Flora

    2017-01-01

    We consider feed-forward and auto-regulation feed-forward neural (weighted) coupled cell networks. In feed-forward neural networks, cells are arranged in layers such that the cells of the first layer have empty input set and cells of each other layer receive only inputs from cells of the previous layer. An auto-regulation feed-forward neural coupled cell network is a feed-forward neural network where additionally some cells of the first layer have auto-regulation, that is, they have a self-loop. Given a network structure, a robust pattern of synchrony is a space defined in terms of equalities of cell coordinates that is flow-invariant for any coupled cell system (with additive input structure) associated with the network. In this paper, we describe the robust patterns of synchrony for feed-forward and auto-regulation feed-forward neural networks. Regarding feed-forward neural networks, we show that only cells in the same layer can synchronize. On the other hand, in the presence of auto-regulation, we prove that cells in different layers can synchronize in a robust way and we give a characterization of the possible patterns of synchrony that can occur for auto-regulation feed-forward neural networks.

  3. Regional-scale climate-variability synchrony of cholera epidemics in West Africa

    Directory of Open Access Journals (Sweden)

    Petit Michel

    2007-03-01

    Full Text Available Abstract Background The relationship between cholera and climate was explored in Africa, the continent with the most reported cases, by analyzing monthly 20-year cholera time series for five coastal adjoining West African countries: Côte d'Ivoire, Ghana, Togo, Benin and Nigeria. Methods We used wavelet analyses and derived methods because these are useful mathematical tools to provide information on the evolution of the periodic component over time and allow quantification of non-stationary associations between time series. Results The temporal variability of cholera incidence exhibits an interannual component, and a significant synchrony in cholera epidemics is highlighted at the end of the 1980's. This observed synchrony across countries, even if transient through time, is also coherent with both the local variability of rainfall and the global climate variability quantified by the Indian Oscillation Index. Conclusion Results of this study suggest that large and regional scale climate variability influence both the temporal dynamics and the spatial synchrony of cholera epidemics in human populations in the Gulf of Guinea, as has been described for two other tropical regions of the world, western South America and Bangladesh.

  4. Midazolam sedation increases fluctuation and synchrony of the resting brain BOLD signal.

    Science.gov (United States)

    Kiviniemi, Vesa J; Haanpää, Hannu; Kantola, Juha-Heikki; Jauhiainen, Jukka; Vainionpää, Vilho; Alahuhta, Seppo; Tervonen, Osmo

    2005-05-01

    The blood oxygen level-dependent (BOLD) magnetic resonance signal of functional brain cortices is dominated by very low frequency (VLF) fluctuations in anesthetized child patients. The temporal synchrony of the BOLD signal is also higher in anesthetized children compared with awake adults. The origin of the synchronous fluctuations can be related to maturation, pathological status or the anesthesia used in the imaging. Two of the three confounding variables (maturation and pathology) were controlled in this study. The effect of midazolam (4+/-0.8 mg) sedation on the BOLD signal was assessed in 12 healthy adults (aged 24+/-1.5 years) at 1.5 T. The VLF fluctuation power and temporal synchrony of the BOLD signal increased significantly after the sedation in the auditory and visual cortices. The fast Fourier transformation power spectral baseline fit parameters of the BOLD signal were also found to change significantly after sedation. It is concluded that the VLF fluctuation and temporal synchrony of the BOLD signal become increased after sedation in functional brain regions.

  5. Rhythms and blues: modulation of oscillatory synchrony and the mechanism of action of antidepressant treatments.

    Science.gov (United States)

    Leuchter, Andrew F; Hunter, Aimee M; Krantz, David E; Cook, Ian A

    2015-05-01

    Treatments for major depressive disorder (MDD) act at different hierarchical levels of biological complexity, ranging from the individual synapse to the brain as a whole. Theories of antidepressant medication action traditionally have focused on the level of cell-to-cell interaction and synaptic neurotransmission. However, recent evidence suggests that modulation of synchronized electrical activity in neuronal networks is a common effect of antidepressant treatments, including not only medications, but also neuromodulatory treatments such as repetitive transcranial magnetic stimulation. Synchronization of oscillatory network activity in particular frequency bands has been proposed to underlie neurodevelopmental and learning processes, and also may be important in the mechanism of action of antidepressant treatments. Here, we review current research on the relationship between neuroplasticity and oscillatory synchrony, which suggests that oscillatory synchrony may help mediate neuroplastic changes related to neurodevelopment, learning, and memory, as well as medication and neuromodulatory treatment for MDD. We hypothesize that medication and neuromodulation treatments may have related effects on the rate and pattern of neuronal firing, and that these effects underlie antidepressant efficacy. Elucidating the mechanisms through which oscillatory synchrony may be related to neuroplasticity could lead to enhanced treatment strategies for MDD.

  6. Role of myelin plasticity in oscillations and synchrony of neuronal activity.

    Science.gov (United States)

    Pajevic, S; Basser, P J; Fields, R D

    2014-09-12

    Conduction time is typically ignored in computational models of neural network function. Here we consider the effects of conduction delays on the synchrony of neuronal activity and neural oscillators, and evaluate the consequences of allowing conduction velocity (CV) to be regulated adaptively. We propose that CV variation, mediated by myelin, could provide an important mechanism of activity-dependent nervous system plasticity. Even small changes in CV, resulting from small changes in myelin thickness or nodal structure, could have profound effects on neuronal network function in terms of spike-time arrival, oscillation frequency, oscillator coupling, and propagation of brain waves. For example, a conduction delay of 5ms could change interactions of two coupled oscillators at the upper end of the gamma frequency range (∼100Hz) from constructive to destructive interference; delays smaller than 1ms could change the phase by 30°, significantly affecting signal amplitude. Myelin plasticity, as another form of activity-dependent plasticity, is relevant not only to nervous system development but also to complex information processing tasks that involve coupling and synchrony among different brain rhythms. We use coupled oscillator models with time delays to explore the importance of adaptive time delays and adaptive synaptic strengths. The impairment of activity-dependent myelination and the loss of adaptive time delays may contribute to disorders where hyper- and hypo-synchrony of neuronal firing leads to dysfunction (e.g., dyslexia, schizophrenia, epilepsy). Published by Elsevier Ltd.

  7. Rhythms and blues: modulation of oscillatory synchrony and the mechanism of action of antidepressant treatments

    Science.gov (United States)

    Leuchter, Andrew F.; Hunter, Aimee M.; Krantz, David E.; Cook, Ian A.

    2015-01-01

    Treatments for major depressive disorder (MDD) act at different hierarchical levels of biological complexity, ranging from the individual synapse to the brain as a whole. Theories of antidepressant medication action traditionally have focused on the level of cell-to-cell interaction and synaptic neurotransmission. However, recent evidence suggests that modulation of synchronized electrical activity in neuronal networks is a common effect of antidepressant treatments, including not only medications, but also neuromodulatory treatments such as repetitive transcranial magnetic stimulation. Synchronization of oscillatory network activity in particular frequency bands has been proposed to underlie neurodevelopmental and learning processes, and also may be important in the mechanism of action of antidepressant treatments. Here, we review current research on the relationship between neuroplasticity and oscillatory synchrony, which suggests that oscillatory synchrony may help mediate neuroplastic changes related to neurodevelopment, learning, and memory, as well as medication and neuromodulatory treatment for MDD. We hypothesize that medication and neuromodulation treatments may have related effects on the rate and pattern of neuronal firing, and that these effects underlie antidepressant efficacy. Elucidating the mechanisms through which oscillatory synchrony may be related to neuroplasticity could lead to enhanced treatment strategies for MDD. PMID:25809789

  8. Scaling analysis on filtered near wall turbulence

    Science.gov (United States)

    Mohan, Prakash; Moser, Robert

    2016-11-01

    Large Eddy Simulations (LES) directly represent larger scale turbulent motions and model the effects of small scale motions. However in the near wall region the large dynamically important eddies scale in viscous wall units, which makes resolving them in a high Reynolds number LES very expensive. This motivates the use of wall-modeled LES, in which these near-wall eddies are modeled. To aid in the development of new wall models, we pursue an asymptotic analysis of the filtered Navier-Stokes equations, in the limit in which the horizontal filter scale is large compared to the thickness of the wall layer. It will be shown that in this limit the filtered velocities u and subgrid stresses τ in the near-wall layer are determined to zeroth order by filtered velocities at the boundary of the wall layer. Further the asymptotics suggest that there is a scaled universal velocity profile f and subgrid stress profile g in the near-wall region. The validity of this result will be tested and the profiles f and g will be evaluated through analysis of DNS data from channel flow at Reτ = 5200 .

  9. Proportional assist ventilation decreases thoracoabdominal asynchrony and chest wall distortion in preterm infants.

    Science.gov (United States)

    Musante, G; Schulze, A; Gerhardt, T; Everett, R; Claure, N; Schaller, P; Bancalari, E

    2001-02-01

    Thoracoabdominal asynchrony (TAA) and chest wall distortion (CWD) are commonly seen in preterm infants secondary to a highly compliant rib cage and poor compensation of distorting forces by inspiratory rib cage muscles. Continuous positive airway pressure (CPAP) reduces TAA and CWD by stenting the chest wall. We hypothesized that application of positive airway pressure only during inspiration and in proportion to an infant's inspiratory effort should have a similar but more pronounced effect than CPAP alone. A ventilator providing airway pressure changes in proportion to flow and volume generated by an infant (proportional assist ventilation) was used to unload the respiratory pump during inspiration. Ten preterm infants were studied [birth weight, 745 (635-1175) g; gestational age, 26.5 (24-31) wk; postnatal age 3 (1-7) d; medium (range)]. TAA and CWD were determined by respiratory inductive plethysmography. TAA was expressed as the phase angle between the rib cage and abdominal motion and CWD as the total compartmental displacement ratio. In addition, we measured tidal volume with a pneumotachograph and esophageal and airway pressure deflections with pressure transducers. Measurements were obtained during alternating periods of CPAP and two different degrees of support (Gain 1 = 1.09 +/- 0.68, Gain 2 = 1.84 +/- 0.84 cm H(2)O/mL) that were provided by a proportional assist ventilator. Phase angle and the total compartmental displacement ratio decreased with increasing gain compared with CPAP alone. Peak airway pressure increased from 0.6 to 3.8 to 7.6 cm H(2)O above positive end-expiratory pressure (PEEP) with CPAP, Gain 1, and Gain 2, respectively, as tidal volume increased from 2.8 to 4.1 to 4.7 mL/kg. Esophageal pressure changes decreased only little with increasing gain. Chest wall excursion increased and abdominal movement decreased, indicating a redistribution of tidal volume between chest and abdomen. We conclude that proportional assist ventilation reduces

  10. Assessment of vascular contrast and wall motion of the aortic root and ascending aorta on MDCT angiography: dual-source high-pitch vs non-gated single-source acquisition schemes

    Energy Technology Data Exchange (ETDEWEB)

    Christensen, Jared D.; Seaman, Danielle M.; Lungren, Matthew P.; Hurwitz, Lynne M.; Boll, Daniel T. [Duke University Medical Center, Department of Radiology, Durham, NC (United States)

    2014-05-15

    This retrospective study assessed whether dual-source high-pitch computed tomographic angiography (CTA) offered advantages over single-source standard-pitch techniques in the evaluation of the ascending aorta. Twenty patients who received both thoracic dual-source high-pitch and single-source standard-pitch CTAs within 1 year were assessed. Dual-source CTAs were performed; standard-pitch imaging used dose-modulated 120 kVp/150 mAs and 0.8 pitch compared with high-pitch protocols employing dose-modulated 120 kVp/250 mAs and 2.4 target pitch. Radiation dose was documented. Contrast-to-noise ratios (CNRs) at sinuses of the Valsalva (CNR{sub Valsalva}) and ascending aorta (CNR{sub Aorta}) were calculated. Dose/CNR for each technique was compared with paired t-tests. Motion at aortic valve, aortic root and ascending aorta were assessed with four-point scales and Mann-Whitney U tests; longitudinal extension of motion was compared with paired t-tests. Significantly lower motion scores for high-pitch, compared with standard-pitch acquisitions for aortic annulus, 0 vs. 2, aortic root, 0 vs. 3, and ascending aorta, 0 vs. 2, were achieved. Significantly reduced longitudinal extension of motion at aortic root, 4.9 mm vs 15.7 mm, and ascending aorta, 4.9 mm vs 21.6 mm, was observed. Contrast was not impacted: CNR{sub Valsalva}, 45.6 vs 46.3, and CNR{sub Aorta}, 45.3 vs 47.1. CTDI{sub vol} was significantly decreased for high-pitch acquisitions, 13.9 mGy vs 15.8 mGy. Dual-source high-pitch CTAs significantly decreased motion artefact without negatively impacting vascular contrast and radiation dose. circle Dual-source high-pitch CTA significantly decreased motion artefact of the ascending aorta. circle Dual-source high-pitch CTA did not negatively impact on vascular contrast. circle Dual-source high-pitch CTA significantly decreased radiation dose compared with single-source standard-pitch acquisitions. (orig.)

  11. Coast-wide recruitment dynamics of Olympia oysters reveal limited synchrony and multiple predictors of failure.

    Science.gov (United States)

    Wasson, Kerstin; Hughes, Brent B; Berriman, John S; Chang, Andrew L; Deck, Anna K; Dinnel, Paul A; Endris, Charlie; Espinoza, Michael; Dudas, Sarah; Ferner, Matthew C; Grosholz, Edwin D; Kimbro, David; Ruesink, Jennifer L; Trimble, Alan C; Vander Schaaf, Dick; Zabin, Chela J; Zacherl, Danielle C

    2016-12-01

    Recruitment of new propagules into a population can be a critical determinant of adult density. We examined recruitment dynamics in the Olympia oyster (Ostrea lurida), a species occurring almost entirely in estuaries. We investigated spatial scales of interannual synchrony across 37 sites in eight estuaries along 2,500 km of Pacific North American coastline, predicting that high vs. low recruitment years would coincide among neighboring estuaries due to shared exposure to regional oceanographic factors. Such synchrony in recruitment has been found for many marine species and some migratory estuarine species, but has never been examined across estuaries in a species that can complete its entire life cycle within the same estuary. To inform ongoing restoration efforts for Olympia oysters, which have declined in abundance in many estuaries, we also investigated predictors of recruitment failure. We found striking contrasts in absolute recruitment rate and frequency of recruitment failure among sites, estuaries, and years. Although we found a positive relationship between upwelling and recruitment, there was little evidence of synchrony in recruitment among estuaries along the coast, and only limited synchrony of sites within estuaries, suggesting recruitment rates are affected more strongly by local dynamics within estuaries than by regional oceanographic factors operating at scales encompassing multiple estuaries. This highlights the importance of local wetland and watershed management for the demography of oysters, and perhaps other species that can complete their entire life cycle within estuaries. Estuaries with more homogeneous environmental conditions had greater synchrony among sites, and this led to the potential for estuary-wide failure when all sites had no recruitment in the same year. Environmental heterogeneity within estuaries may thus buffer against estuary-wide recruitment failure, analogous to the portfolio effect for diversity. Recruitment failure

  12. Seismic displacement of gravity retaining walls

    Directory of Open Access Journals (Sweden)

    Kamal Mohamed Hafez Ismail Ibrahim

    2015-08-01

    Full Text Available Seismic displacement of gravity walls had been studied using conventional static methods for controlled displacement design. In this study plain strain numerical analysis is performed using Plaxis dynamic program where prescribed displacement is applied at the bottom boundary of the soil to simulate the applied seismic load. Constrained absorbent side boundaries are introduced to prevent any wave reflection. The studied soil is chosen dense granular sand and modeled as elasto-plastic material according to Mohr–Column criteria while the gravity wall is assumed elastic. By comparing the resulted seismic wall displacements calculated by numerical analysis for six historical ground motions with that calculated by the pseudo-static method, it is found that numerical seismic displacements are either equal to or greater than corresponding pseudo-static values. Permissible seismic wall displacement calculated by AASHTO can be used for empirical estimation of seismic displacement. It is also found that seismic wall displacement is directly proportional with the positive angle of inclination of the back surface of the wall, soil flexibility and with the earthquake maximum ground acceleration. Seismic wall sliding is dominant and rotation is negligible for rigid walls when the ratio between the wall height and the foundation width is less than 1.4, while for greater ratios the wall becomes more flexible and rotation (rocking increases till the ratio reaches 1.8 where overturning is susceptible to take place. Cumulative seismic wall rotation increases with dynamic time and tends to be constant at the end of earthquake.

  13. Neuromolecular Imaging Shows Temporal Synchrony Patterns between Serotonin and Movement within Neuronal Motor Circuits in the Brain

    Directory of Open Access Journals (Sweden)

    Patricia A. Broderick

    2013-06-01

    Full Text Available The present discourse links the electrical and chemical properties of the brain with neurotransmitters and movement behaviors to further elucidate strategies to diagnose and treat brain disease. Neuromolecular imaging (NMI, based on electrochemical principles, is used to detect serotonin in nerve terminals (dorsal and ventral striata and somatodendrites (ventral tegmentum of reward/motor mesocorticolimbic and nigrostriatal brain circuits. Neuronal release of serotonin is detected at the same time and in the same animal, freely moving and unrestrained, while open-field behaviors are monitored via infrared photobeams. The purpose is to emphasize the unique ability of NMI and the BRODERICK PROBE® biosensors to empirically image a pattern of temporal synchrony, previously reported, for example, in Aplysia using central pattern generators (CPGs, serotonin and cerebral peptide-2. Temporal synchrony is reviewed within the context of the literature on central pattern generators, neurotransmitters and movement disorders. Specifically, temporal synchrony data are derived from studies on psychostimulant behavior with and without cocaine while at the same time and continuously, serotonin release in motor neurons within basal ganglia, is detected. The results show that temporal synchrony between the neurotransmitter, serotonin and natural movement occurs when the brain is NOT injured via, e.g., trauma, addictive drugs or psychiatric illness. In striking contrast, in the case of serotonin and cocaine-induced psychostimulant behavior, a different form of synchrony and also asynchrony can occur. Thus, the known dysfunctional movement behavior produced by cocaine may well be related to the loss of temporal synchrony, the loss of the ability to match serotonin in brain with motor activity. The empirical study of temporal synchrony patterns in humans and animals may be more relevant to the dynamics of motor circuits and movement behaviors than are studies of

  14. Two-dimensional speckle-tracking echocardiographic assessment of left ventricular mechanical synchrony in clinically normal cats

    Directory of Open Access Journals (Sweden)

    Hsu YL

    2016-03-01

    Full Text Available Yueh-Lun Hsu, Hui-Pi Huang Institute of Veterinary Clinical Science, Veterinary School, National Taiwan University, Taipei, Taiwan Abstract: Ventricular heterogeneity and synchrony are associated with hypertrophic cardiomyopathy in humans. Hypertrophic cardiomyopathy is commonly observed in cats. The aim of this study was to determine the presence and normal range of left ventricular mechanical heterogeneity and synchrony in clinically healthy cats using two-dimensional speckle-tracking echocardiography. Thirty-four clinically healthy cats were included in this prospective study. Two-dimensional echocardiography and two-dimensional speckle-tracking echocardiography were performed on all cats. Echocardiographic parameters, including circumferential, radial, and longitudinal strain and strain rate, heterogeneity, and synchrony, were measured. Segmental heterogeneity values in the circumferential, radial, and longitudinal directions were 13.1%±5.9%, 19.1%±10.3%, and 15.4%±6.8%, respectively. Transmural heterogeneity was -14.3%±4.6% in the circumferential direction. Left ventricular synchrony values in the circumferential, radial, and longitudinal directions were 11.7±4.2, 16.5±13.4, and 19.4±8.5 ms, respectively. Interventricular synchrony was -3.9±13.2 ms. Left ventricular heterogeneity and synchrony were noted in clinically healthy cats; segmental heterogeneity, which is characterized as longitudinal, progressively increased from the apical to the basal segments, while transmural heterogeneity, which is characterized as circumferential, progressively decreased from the endocardium to the epicardium. Keywords: feline, ventricular heterogeneity, synchrony

  15. Domain wall motion and electromechanical strain in lead-free piezoelectrics: Insight from the model system (1 − x)Ba(Zr{sub 0.2}Ti{sub 0.8})O{sub 3}–x(Ba{sub 0.7}Ca{sub 0.3})TiO{sub 3} using in situ high-energy X-ray diffraction during application of electric fields

    Energy Technology Data Exchange (ETDEWEB)

    Tutuncu, Goknur [Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611 (United States); Li, Binzhi [Department of Chemical Engineering and Materials Science, University of California, Davis, Davis, California 95616 (United States); Bowman, Keith [Illinois Institute of Technology, Armour College of Engineering, Chicago, Illinois 60616 (United States); School of Materials Engineering, Purdue University, West Lafayette, Indiana 47907 (United States); Jones, Jacob L., E-mail: JacobJones@ncsu.edu [Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States)

    2014-04-14

    The piezoelectric compositions (1 − x)Ba(Zr{sub 0.2}Ti{sub 0.8})O{sub 3}–x(Ba{sub 0.7}Ca{sub 0.3})TiO{sub 3} (BZT-xBCT) span a model lead-free morphotropic phase boundary (MPB) between room temperature rhombohedral and tetragonal phases at approximately x = 0.5. In the present work, in situ X-ray diffraction measurements during electric field application are used to elucidate the origin of electromechanical strain in several compositions spanning the tetragonal compositional range 0.6 ≤ x ≤ 0.9. As BCT concentration decreases towards the MPB, the tetragonal distortion (given by c/a-1) decreases concomitantly with an increase in 90° domain wall motion. The increase in observed macroscopic strain is predominantly attributed to the increased contribution from 90° domain wall motion. The results demonstrate that domain wall motion is a significant factor in achieving high strain and piezoelectric coefficients in lead-free polycrystalline piezoelectrics.

  16. Century-scale Changes in Environmental Synchrony and Variability and their Effects on Populations of Birds and Reproduction of Trees

    Science.gov (United States)

    Koenig, W.

    2016-12-01

    The ecological impacts of modern global climate change are detectable in a wide variety of phenomena ranging from shifts in species ranges to changes in community composition and human disease dynamics. Thus far, however, little attention has been given to temporal changes in environmental spatial synchrony-the coincident change in abundance or value across the landscape-or environmental variability, despite the importance of these factors as drivers of population rescue and extinction and reproductive dynamics of both animal and plant populations. We quantified spatial synchrony of widespread North American wintering birds species using Audubon Christmas Bird Counts over the past 50 years and seed set variability (mast fruiting) among trees over the past century and found that both spatial synchrony of the birds and seed set variability have significantly increased over these time periods. The first of these results was mirrored by significant increases in spatial synchrony of mean maximum air temperature across North America, primarily during the summer, while the second is consistent with the hypothesis that climate change is resulting in greater seed set variability. These findings suggest the potential for temporal changes in envioronmental synchrony and variability to be affecting a wide range of ecological phenomena by influencing the probability of population rescue and extinction and by affecting ecosystem processes that rely on the resource pulses provided by mast fruiting plants.

  17. In-situ observation of domain wall motion in Pb(In{sub 1/2}Nb{sub 1/2})O{sub 3}-Pb(Mg{sub 1/3}Nb{sub 2/3})O{sub 3}-PbTiO{sub 3} crystals

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Dabin; Cai, Changlong [Laboratory of Thin Film Techniques and Optical Test, Xi' an Technological University, Xi' an 710032 (China); Li, Zhenrong, E-mail: zhrli@mail.xjtu.edu.cn; Li, Fei; Xu, Zhuo [Electronic Materials Research Laboratory, Key Laboratory of Education Ministry and International Center for Dielectric Research, Xi' an Jiaotong University, Xi' an 710049 (China); Zhang, Shujun, E-mail: soz1@psu.edu [Materials Research Institute, Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Cheng, Yaojin [Science and Technology on Low-Light-Level Night Vision Laboratory, Xi' an 710065 (China)

    2014-07-21

    Various domain structures, including wave-like domains, mixed needle-like and laminar domains, typical embedded 90° and 180° domains, have been observed in unpoled rhombohedral, monoclinic, and tetragonal Pb(In{sub 1/2}Nb{sub 1/2})O{sub 3}-Pb(Mg{sub 1/3}Nb{sub 2/3})O{sub 3}-PbTiO{sub 3} (PIN-PMN-PT) crystals by polarizing light microscope; while in poled tetragonal crystals, the parallel 180° domains were reversed and only vertical 90° domain walls were observed. For 0.24PIN-0.42PMN-0.34PT crystals with morphotropic phase boundary composition, the domain wall motion was in-situ observed as a function of applied electric field along crystallographic [100] direction. With increasing the electric field from 0 to 12 kV/cm, the rhombohedral (R) domains were found to change to monoclinic (M) domains and then to tetragonal (T) domains. The electric field-induced phase transition was also confirmed by X-ray diffraction and the temperature-dependent dielectric behavior.

  18. The interaction of intrinsic dynamics and network topology in determining network burst synchrony.

    Science.gov (United States)

    Gaiteri, Chris; Rubin, Jonathan E

    2011-01-01

    The pre-Bötzinger complex (pre-BötC), within the mammalian respiratory brainstem, represents an ideal system for investigating the synchronization properties of complex neuronal circuits via the interaction of cell-type heterogeneity and network connectivity. In isolation, individual respiratory neurons from the pre-BötC may be tonically active, rhythmically bursting, or quiescent. Despite this intrinsic heterogeneity, coupled networks of pre-BötC neurons en bloc engage in synchronized bursting that can drive inspiratory motor neuron activation. The region's connection topology has been recently characterized and features dense clusters of cells with occasional connections between clusters. We investigate how the dynamics of individual neurons (quiescent/bursting/tonic) and the betweenness centrality of neurons' positions within the network connectivity graph interact to govern network burst synchrony, by simulating heterogeneous networks of computational model pre-BötC neurons. Furthermore, we compare the prevalence and synchrony of bursting across networks constructed with a variety of connection topologies, analyzing the same collection of heterogeneous neurons in small-world, scale-free, random, and regularly structured networks. We find that several measures of network burst synchronization are determined by interactions of network topology with the intrinsic dynamics of neurons at central network positions and by the strengths of synaptic connections between neurons. Surprisingly, despite the functional role of synchronized bursting within the pre-BötC, we find that synchronized network bursting is generally weakest when we use its specific connection topology, which leads to synchrony within clusters but poor coordination across clusters. Overall, our results highlight the relevance of interactions between topology and intrinsic dynamics in shaping the activity of networks and the concerted effects of connectivity patterns and dynamic heterogeneities.

  19. Modulation of Purkinje cell complex spike waveform by synchrony levels in the olivocerebellar system.

    Science.gov (United States)

    Lang, Eric J; Tang, Tianyu; Suh, Colleen Y; Xiao, Jianqiang; Kotsurovskyy, Yuriy; Blenkinsop, Timothy A; Marshall, Sarah P; Sugihara, Izumi

    2014-01-01

    Purkinje cells (PCs) generate complex spikes (CSs) when activated by the olivocerebellar system. Unlike most spikes, the CS waveform is highly variable, with the number, amplitude, and timing of the spikelets that comprise it varying with each occurrence. This variability suggests that CS waveform could be an important control parameter of olivocerebellar activity. The origin of this variation is not well known. Thus, we obtained extracellular recordings of CSs to investigate the possibility that the electrical coupling state of the inferior olive (IO) affects the CS waveform. Using multielectrode recordings from arrays of PCs we showed that the variance in the recording signal during the period when the spikelets occur is correlated with CS synchrony levels in local groups of PCs. The correlation was demonstrated under both ketamine and urethane, indicating that it is robust. Moreover, climbing fiber reflex evoked CSs showed an analogous positive correlation between spikelet-related variance and the number of cells that responded to a stimulus. Intra-IO injections of GABA-A receptor antagonists or the gap junction blocker carbenoxolone produced correlated changes in the variance and synchrony levels, indicating the presence of a causal relationship. Control experiments showed that changes in variance with synchrony were primarily due to changes in the CS waveform, as opposed to changes in the strength of field potentials from surrounding cells. Direct counts of spikelets showed that their number increased with synchronization of CS activity. In sum, these results provide evidence of a causal link between two of the distinguishing characteristics of the olivocerebellar system, its ability to generate synchronous activity and the waveform of the CS.

  20. Effects of right atrial and ventricular DDD pacing on cardiac function and ventricular contraction synchrony

    Institute of Scientific and Technical Information of China (English)

    支力大; 华伟; 张澍; 史蓉芳; 王方正; 陈新

    2004-01-01

    Background Right ventricular apical pacing has been reported to reduce cardiac performance. But there are few reports on the effects of dual chamber (DDD) pacing on cardiac function compared to sinus rhythm. In this study, we evaluated the effects of right atrial and ventricular DDD pacing on cardiac function and ventricular contraction synchrony using equilibrium radionuclide angiography.Methods Ten patients implanted with a right atrial and ventricular DDD pacemaker underwent equilibrium radionuclide angiography. The scintigraphic data were obtained during sinus rhythm and pacing rhythm. Cardiac function parameters were obtained semimanually. Phase analysis was used to study the ventricular activation sequence and ventricular synchrony.Results The left ventricular 1/3 ejection fraction decreased significantly during pacing compared with that during sinus rhythm[(23.4 ±6.1)% vs(27.7 ±4.5)%, P =0.01]. Regional ejection fraction also decreased during pacing, although the difference was not statistically significant. Phase analysis showed that the right ventricle was activated earlier than the left ventricle during pacing, and that the phase shift was significantly greater during pacing than that during sinus rhythm[64.13°±16.80° vs 52.88°± 9.26°, P =0.007]. The activation of both ventricles occurred simultaneously during sinus rhythm, with the activation sequence from proximal septum or base of left ventricle to apex. The earliest activation during pacing occurred at the right ventricular apex, and subsequently spread to the base and left ventricle.Conclusion Right atrial and ventricular DDD pacing impairs left ventricular systolic function and ventricular synchrony.

  1. PySpike - A Python library for analyzing spike train synchrony

    CERN Document Server

    Mulansky, Mario

    2016-01-01

    Understanding how the brain functions is one of the biggest challenges of our time. The analysis of experimentally recorded neural firing patterns (spike trains) plays a crucial role in addressing this problem. Here, the PySpike library is introduced, a Python package for spike train analysis providing parameter-free and time-scale independent measures of spike train synchrony. It allows to compute bi- and multivariate dissimilarity profiles, averaged values and bivariate matrices. Although mainly focusing on neuroscience, PySpike can also be applied in other contexts like climate research or social sciences. The package is available as Open Source on Github and PyPI.

  2. Pacemaker repetitive nonreentrant ventriculoatrial synchrony. Why did automatic mode switching occur?

    Science.gov (United States)

    Barold, S Serge; Stroobandt, Roland X; Van Heuverswyn, Frederic

    2012-01-01

    Repetitive nonreentrant ventriculoatrial synchrony during dual-chamber pacing is characterized by long intervals alternating with short intervals. This arrangement activated automatic mode switching in a St Jude dual-chamber pacemaker in which the algorithm requires an atrial sensed event for automatic mode switching initiation. Automatic mode switching activation by an atrial sensed event (retrograde P wave) was puzzling because the programmed postventricular atrial period was longer than the retrograde ventriculoatrial conduction time. The explanation is presented in the form of questions and answers to facilitate the understanding of pacemaker function and complex timing cycles.

  3. Isochronal synchrony and bidirectional communication with delay-coupled nonlinear oscillators

    Science.gov (United States)

    Zhou, Brian B.; Roy, Rajarshi

    2007-02-01

    We propose a basic mechanism for isochronal synchrony and communication with mutually delay-coupled chaotic systems. We show that two Ikeda ring oscillators, mutually coupled with a propagation delay, synchronize isochronally when both are symmetrically driven by a third Ikeda oscillator. This synchronous operation, unstable in the two delay-coupled oscillators alone, facilitates simultaneous, bidirectional communication of messages with chaotic carrier wave forms. This approach to combine both bidirectional and unidirectional coupling represents an application of generalized synchronization using a mediating drive signal for a spatially distributed and internally synchronized multicomponent system.

  4. [Development of an automatic pneumatic tourniquet system that determines pressures in synchrony with systolic blood pressure].

    Science.gov (United States)

    Liu, Hongyun; Li, Kaiyuan; Zhang, Zhengbo; Guo, Junyan; Wang, Weidong

    2012-11-01

    The correlation coefficients between arterial occlusion pressure and systolic blood pressure, diastolic blood pressure, limb circumference, body mass etc were obtained through healthy volunteer experiments, in which tourniquet were applied on upper/lower extremities. The prediction equations were derived from the data of experiments by multiple regression analysis. Based on the microprocessor C8051F340, a new pneumatic tourniquet system that can determine tourniquet pressure in synchrony with systolic blood pressure was developed and verified the function and stability of designed system. Results showed that the pneumatic tourniquet which automatically adjusts occlusion pressure in accordance with systolic blood pressure could stop the flow of blood to get a bloodless field.

  5. PySpike—A Python library for analyzing spike train synchrony

    Directory of Open Access Journals (Sweden)

    Mario Mulansky

    2016-01-01

    Full Text Available Understanding how the brain functions is one of the biggest challenges of our time. The analysis of experimentally recorded neural firing patterns (spike trains plays a crucial role in addressing this problem. Here, the PySpike library is introduced, a Python package for spike train analysis providing parameter-free and time-scale independent measures of spike train synchrony. It allows to compute similarity and dissimilarity profiles, averaged values and distance matrices. Although mainly focusing on neuroscience, PySpike can also be applied in other contexts like climate research or social sciences. The package is available as Open Source on Github and PyPI.

  6. Judged and Remembered Trustworthiness of Faces Is Enhanced by Experiencing Multisensory Synchrony and Asynchrony in the Right Order.

    Science.gov (United States)

    Toscano, Hugo; Schubert, Thomas W

    2015-01-01

    This work builds on the enfacement effect. This effect occurs when experiencing a rhythmic stimulation on one's cheek while seeing someone else's face being touched in a synchronous way. This typically leads to cognitive and social-cognitive effects similar to self-other merging. In two studies, we demonstrate that this multisensory stimulation can change the evaluation of the other's face. In the first study, participants judged the stranger's face and similar faces as being more trustworthy after synchrony, but not after asynchrony. Synchrony interacted with the order of the stroking; hence trustworthiness only changed when the synchronous stimulation occurred before the asynchronous one. In the second study, a synchronous stimulation caused participants to remember the stranger's face as more trustworthy, but again only when the synchronous stimulation came before the asynchronous one. The results of both studies show that order of stroking creates a context in which multisensory synchrony can affect the trustworthiness of faces.

  7. Nonlinear dynamics of domain walls with cross-ties

    Energy Technology Data Exchange (ETDEWEB)

    Dubovik, M. N., E-mail: dubovik@imp.uran.ru [Russian Academy of Sciences, Institute of Metal Physics, Ural Branch (Russian Federation); Zverev, V. V. [Ural Federal University (Russian Federation); Filippov, B. N. [Russian Academy of Sciences, Institute of Metal Physics, Ural Branch (Russian Federation)

    2016-07-15

    The dynamic behavior of a domain wall with cross-ties is analyzed on the basis of micromagnetic simulation with exact allowance for all main (exchange, magnetoanisotropic, and magnetostatic) interactions in thin magnetically uniaxial ferromagnetic films with planar anisotropy. It is found that the peculiarities of motion of such domain walls are closely related to the behavior of topological defects in the magnetization distribution (generation, motion, and annihilation of vortex–antivortex pairs on the film surface and Bloch points). We observe three different regimes of motion (stationary, periodic, and turbulent regimes), each of which is realized in a certain range of fields oriented along the easy magnetization axis. It is shown that the experimentally observed dynamic bends of the walls with cross-ties are determined by the type of motion of vortices and antivortices. The velocities of domain walls in different regimes are calculated, and the dynamic configurations of the magnetization and existing dynamic transitions between them are investigated.

  8. Nonlinear dynamics of domain walls with cross-ties

    Science.gov (United States)

    Dubovik, M. N.; Zverev, V. V.; Filippov, B. N.

    2016-07-01

    The dynamic behavior of a domain wall with cross-ties is analyzed on the basis of micromagnetic simulation with exact allowance for all main (exchange, magnetoanisotropic, and magnetostatic) interactions in thin magnetically uniaxial ferromagnetic films with planar anisotropy. It is found that the peculiarities of motion of such domain walls are closely related to the behavior of topological defects in the magnetization distribution (generation, motion, and annihilation of vortex-antivortex pairs on the film surface and Bloch points). We observe three different regimes of motion (stationary, periodic, and turbulent regimes), each of which is realized in a certain range of fields oriented along the easy magnetization axis. It is shown that the experimentally observed dynamic bends of the walls with cross-ties are determined by the type of motion of vortices and antivortices. The velocities of domain walls in different regimes are calculated, and the dynamic configurations of the magnetization and existing dynamic transitions between them are investigated.

  9. Do Stops Slow Down Electroweak Bubble Walls?

    CERN Document Server

    John, P

    2001-01-01

    We compute the wall velocity in the MSSM. We therefore generalize the SMequations of motion for bubble walls moving through a hot plasma at theelectroweak phase transition and calculate the friction terms which describethe viscosity of the plasma. We give the general expressions and apply them toa simple model where stops, tops and W bosons contribute to the friction. In awide range of parameters including those which fulfil the requirements ofbaryogenesis we find a wall velocity of order v = 0.001-0.01 much below the SMvalue.

  10. 运动幅度曲线直观评价心肌梗死患者左心室局域舒张功能%Evaluation of regional left ventricular diastolic function in patients with myocardial infarction by the curve of ventricular wall motion

    Institute of Scientific and Technical Information of China (English)

    王世宏

    2008-01-01

    Objective To detect the curve of ventricular wall motion features of regional wall abnor-malities in patients with coronary artery disease during each diastolic period, and its possibility to evaluate re-gional left ventricular diastolic function. Methods Fifty-four patients with anterior myocardial infarction (MI group) and 78 normal subjects (NOR group) underwent Doppler tissue imaging, which were performed in 2-chamber-view by the tracing technology of ventrieular wall motion synchronously. Isovolumic relax-ation period, rapid flow period, slow filling phase, atrial systole period were measured. Results In NOR group, distant value of 76 patients (97.44%) showed a gradually decreasing positive value from the apex to middle and from middle to base of left ventricle. While in MI group, such rules disappeared, 52 patients (96.30%) were negative in infarction area. In isevolumic relaxation period in NOR group, 76 patients (97.44%) showed palliative downward wave, but in MI group, 27 patients (50.00%) showed palliative downward wave(P<0.05). In rapid flow period, both NOR and MI group showed downward and steep waves,but in MI group, the gradient rule disappeared and distance of ventricular wall motion was negative in infarc-tion area. In slow filling phase, compared with NOR group, which had horizontal wave, MI group had no obvi-ously horizontal waves. Conclusion Regional myocardial ischemia and infarction can cause significant ab-normalities of regional ventricular wall motion in active diastolic phase, and it can be evaluated quantitatively and synchronously with high sensitivity by the curve of ventricular wall motion which has the potential value in regional left ventricular diastolic function.%目的 探讨冠心病患者左心室舒张各期局部心肌运动幅度曲线特点及其评价左心室局域舒张功能的可能性.方法 对54例前壁心肌梗死患者(MI组)和78例健康对照者(NOR组)左心室心肌进行组织多普勒成像检查.记录心

  11. Falling walls

    CERN Multimedia

    It was 20 years ago this week that the Berlin wall was opened for the first time since its construction began in 1961. Although the signs of a thaw had been in the air for some time, few predicted the speed of the change that would ensue. As members of the scientific community, we can take a moment to reflect on the role our field played in bringing East and West together. CERN’s collaboration with the East, primarily through links with the Joint Institute for Nuclear Research, JINR, in Dubna, Russia, is well documented. Less well known, however, is the role CERN played in bringing the scientists of East and West Germany together. As the Iron curtain was going up, particle physicists on both sides were already creating the conditions that would allow it to be torn down. Cold war historian Thomas Stange tells the story in his 2002 CERN Courier article. It was my privilege to be in Berlin on Monday, the anniversary of the wall’s opening, to take part in a conference entitled &lsquo...

  12. Motion Simulator

    Science.gov (United States)

    1993-01-01

    MOOG, Inc. supplies hydraulic actuators for the Space Shuttle. When MOOG learned NASA was interested in electric actuators for possible future use, the company designed them with assistance from Marshall Space Flight Center. They also decided to pursue the system's commercial potential. This led to partnership with InterActive Simulation, Inc. for production of cabin flight simulators for museums, expositions, etc. The resulting products, the Magic Motion Simulator 30 Series, are the first electric powered simulators. Movements are computer-guided, including free fall to heighten the sense of moving through space. A projection system provides visual effects, and the 11 speakers of a digital laser based sound system add to the realism. The electric actuators are easier to install, have lower operating costs, noise, heat and staff requirements. The U.S. Space & Rocket Center and several other organizations have purchased the simulators.

  13. Effect of urapidil on heart function and ventricular systolic synchrony in acute myocardial infarction patients with no-reflow phenomenon after percutaneous coronary intervention%乌拉地尔对急性前壁心肌梗死介入治疗后心肌无复流患者心室功能和收缩同步性的影响

    Institute of Scientific and Technical Information of China (English)

    陈金良; 傅向华; 姜云发; 范卫泽; 谷新顺; 刘津军; 耿巍

    2008-01-01

    Objective To evaluate the influence of intracoronary administration of urapidil on myocardial blush grade (MBG) and left ventricular systolic function and synchrony in the acute myocardial infarction (AMI) patients with no-reflow phenomenon after percutaneous coronary intervention (PCI)identified by MBG. Methods Forty-three patients with AMI, in whom primary PCI was successfully performed (6.252.37) hours after the onset of angina pectoris ,were found to have no-reflow phenomenon.They were randomized into two groups: urapidil group (n= 22) and no-fellow control group (n= 21).Nitroglycerin (200 μg) was injected into coronary artery. Urapidil (5 mg) was injected into coronary artery after 10 minutes in the urapidil group, and 0. 9 % NaCl (5 ml, weight percentage) was injected into coronary artery in the no-fellow control group. All the patients received same standard therapy afterwards. The left ventriculography (LVG) was performed immediately and 6 months after PCI to measure the ventrieular volume, left ventricular end-diastolic pressure (LVEDP), and wall motion score (WMS). Equilibrium radionuclide angiography (ERNA) was performed 1 week and 6 months after PCI to determine theparameters of left ventricutar systolic function and systolic synchrony. Results The MBG of urapidil group and control group was grade 0. 775±0.31 and grade 0. 77±0.28 after PCI, respectively. The MBG remained unchanged in control group and significantly increased from grade 0.77 ±0.31 to grade 2.37± 0.2710 minutes in urapidil group (P<0.05). Follow-up at 6 months after AMI-PCI, left ventricular end-systolic volume index (LVESVI), left ventricular end-diastolic volume index (LVEDVI), WMS and LVEDP were significantly lower in urapidil group compared with those in control group respectively (all P<0.05). The values of left ventricular ejection fraction (LVEF), peak ejection rate (PER), peak filling rate (PFR) of the ERNA as measured by ERNA were significantly increased in urapidil

  14. Abnormal synchrony and effective connectivity in patients with schizophrenia and auditory hallucinations

    Science.gov (United States)

    de la Iglesia-Vaya, Maria; Escartí, Maria José; Molina-Mateo, Jose; Martí-Bonmatí, Luis; Gadea, Marien; Castellanos, Francisco Xavier; Aguilar García-Iturrospe, Eduardo J.; Robles, Montserrat; Biswal, Bharat B.; Sanjuan, Julio

    2014-01-01

    Auditory hallucinations (AH) are the most frequent positive symptoms in patients with schizophrenia. Hallucinations have been related to emotional processing disturbances, altered functional connectivity and effective connectivity deficits. Previously, we observed that, compared to healthy controls, the limbic network responses of patients with auditory hallucinations differed when the subjects were listening to emotionally charged words. We aimed to compare the synchrony patterns and effective connectivity of task-related networks between schizophrenia patients with and without AH and healthy controls. Schizophrenia patients with AH (n = 27) and without AH (n = 14) were compared with healthy participants (n = 31). We examined functional connectivity by analyzing correlations and cross-correlations among previously detected independent component analysis time courses. Granger causality was used to infer the information flow direction in the brain regions. The results demonstrate that the patterns of cortico-cortical functional synchrony differentiated the patients with AH from the patients without AH and from the healthy participants. Additionally, Granger-causal relationships between the networks clearly differentiated the groups. In the patients with AH, the principal causal source was an occipital–cerebellar component, versus a temporal component in the patients without AH and the healthy controls. These data indicate that an anomalous process of neural connectivity exists when patients with AH process emotional auditory stimuli. Additionally, a central role is suggested for the cerebellum in processing emotional stimuli in patients with persistent AH. PMID:25379429

  15. Repetitive nonreentrant ventriculoatrial synchrony: An underrecognized cause of pacemaker-related arrhythmia.

    Science.gov (United States)

    Sharma, Parikshit S; Kaszala, Karoly; Tan, Alex Y; Koneru, Jayanthi N; Shepard, Richard; Ellenbogen, Kenneth A; Huizar, Jose F

    2016-08-01

    Similar to endless loop tachycardia (ELT), repetitive nonreentrant ventriculoatrial synchrony (RNRVAS) is a ventriculoatrial (VA) synchrony pacemaker-mediated arrhythmia. RNRVAS was first described in 1990 and can only occur in the presence of retrograde VA conduction and dual-chamber or cardiac resynchronization devices with tracking (P-synchronous ventricular pacing such as DDD, DDDR) or nontracking pacing modes that allow AV-sequential pacing (DDI, DDIR). RNRVAS is promoted by (1) high lower rate limit or any feature that allows rapid pacing, (2) long AV intervals, or (3) long postventricular atrial refractory period (PVARP). In contrast to ELT, RNRVAS is a less well-recognized form of pacemaker-mediated arrhythmia; thus, unlike ELT, there are no specific device algorithms to prevent, recognize, and terminate RNRVAS. However, RNRVAS has been recently shown to occur frequently. We present a series of cases, some of which were found fortuitously. Owing to its clinical implications, we propose that algorithms should be developed to prevent, identify, and terminate RNRVAS.

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

    Science.gov (United States)

    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.

  17. Regional synchrony of temperature variation and internal wave forcing along the Florida Keys reef tract

    Science.gov (United States)

    Leichter, James J.; Stokes, M. Dale; Vilchis, L. Ignacio; Fiechter, Jerome

    2014-01-01

    Analysis of 10 year temperature records collected along the Florida Keys reef tract (FLKRT) reveals strong, regional-scale synchrony in high-frequency temperature variation suggestive of internal wave forcing at predominately semidiurnal frequencies. In each year and at all sites, the amplitude of semidiurnal temperature variation was greatest from March to September, and markedly lower from October to February. Comparisons of the semidiurnal component of the temperature variation among sites suggest complex patterns in the arrival of internal waves, with highest cross correlation among closely spaced sites and synchrony in periods of enhanced internal wave activity across the length of the FLKRT, particularly in summer. The periods of enhanced semidiurnal temperature variation at the 20 and 30 m isobaths on the reef slopes appear to be associated with the dynamics of the Florida Current and the onshore movement of warm fronts preceding the passage of Florida Current frontal eddies. Regional-scale satellite altimetry observations suggest temporal linkages to sea surface height anomalies in the Loop Current (upstream of the Florida Current) and setup of the Tortugas Gyre. The synchronized forcing of cool water onto the reef slope sites across the FLKRT is likely to affect physiological responses to temperature variation in corals and other ectothermic organisms, as well as larval transport and nutrient dynamics with the potential for regionally coherent pulses of larvae and nutrients arriving on reef slopes across the FLKRT.

  18. Children's synchrony and rhythmicity in imitation of peers: toward a developmental model of empathy.

    Science.gov (United States)

    Xavier, Jean; Tilmont, Elodie; Bonnot, Olivier

    2013-09-01

    The main mechanisms of children's imitative exchanges with peers are highlighted here through a developmental approach taking into account the importance of rhythmicity and synchrony. We focused on spontaneous motor imitation to describe a playful dynamic that is paradoxical: in the experience of play in which roles are not clearly distributed, mutual discovery of the self and others gradually arises. From an integrative perspective, this form of interaction, produced by positional reversal and turn taking, is apprehended through two axis. On the temporal plan, it can be considered as a rhythmic pattern with repetition and synchrony. Moreover, these mutual exchanges between the self and others challenge visuo-spatial abilities in children who must be able to change their reference point through an operation of mental rotation. Based on this description of the intersubjective experience produced through a succession of spatial and symbolic viewpoint changes, a developmental model of empathy is offered and discussed. According to this model, the capacity of empathy has two dimensions, emotional and cognitive, and is understood as a process involved in child development. In this article, we propose that empathy is more than the "mere" capacity of decentration corresponding to the acquisition of a theory of mind. It involves an individual in relationship with others and who has the ability to integrate perspectives.

  19. Phase-amplitude coupling and interlaminar synchrony are correlated in human neocortex.

    Science.gov (United States)

    McGinn, Ryan J; Valiante, Taufik A

    2014-11-26

    One of the striking manifestations of neuronal population activity is that of rhythmic oscillations in the local field potential. It is thought that such oscillatory patterns, including phase-amplitude coupling (PAC) and inter-regional synchrony, may represent forms of local and long-range cortical computations, respectively. Although it has been speculated that these two oscillatory patterns are functionally related, and bind disparate cortical assemblies to one another at different timescales, there is little direct evidence to support this hypothesis. We have demonstrated recently that theta to high-gamma PAC and interlaminar phase coherence at theta frequencies can be generated in human cortical slices maintained in vitro. Here we show that not only do such oscillatory patterns exist within human temporal neocortex, but that the strength of one is related to the strength of the other. We demonstrate that at theta frequencies, metrics of temporal synchrony between superficial and deep cortical laminae (phase-dependent power correlations, and phase coherence) are correlated to the magnitude of intralaminar PAC between theta and high-gamma. Specifically, our results suggest that interlaminar communication within human temporal neocortex and local laminar excitability are linked to one another through a dependence mediated by theta oscillations. More generally, our results provide evidence for the hypothesis that theta oscillations may coordinate inter-areal excitability in the human brain.

  20. Testing for synchrony in recruitment among four Lake Michigan fish species

    Science.gov (United States)

    Bunnell, David; Höök, Tomas O.; Troy, Cary D.; Liu, Wentao; Madenjian, Charles P.; Adams, Jean V.

    2017-01-01

    In the Great Lakes region, multiple fish species display intra-specific spatial synchrony in 28 recruitment success, with inter-annual climate variation hypothesized as the most likely driver. 29 In Lake Michigan, we evaluated whether climatic or other physical variables could also induce 30 spatial synchrony across multiple species, including bloater (Coregonus hoyi), rainbow smelt 31 (Osmerus mordax), yellow perch (Perca flavescens), and alewife (Alosa pseudoharengus). The 32 residuals from stock-recruitment relationships revealed yellow perch recruitment to be correlated 33 with recruitment of both rainbow smelt (r = 0.37) and alewife (r = 0.36). Across all four species, 34 higher than expected recruitment occurred in 5 years between 1978 and 1987 and then switched 35 to lower than expected recruitment in 5 years between 1996 and 2004. Generalized additive 36 models revealed warmer spring and summer water temperatures and lower wind speeds 37 corresponded to higher than expected recruitment for the nearshore-spawning species, and 38 overall variance explained ranged from 14% (yellow perch) to 61% (alewife). For all species 39 but rainbow smelt, higher recruitment also occurred in extremely high or low years of the North 40 Atlantic Oscillation index. Future development of indices that describe the physical Great Lakes 41 environment could improve understanding of how climate can synchronize fish populations 42 within and across species.

  1. Structural (operational) synchrony of EEG alpha activity during an auditory memory task.

    Science.gov (United States)

    Fingelkurts, Andrew; Fingelkurts, Alexander; Krause, Christina; Kaplan, Alexander; Borisov, Sergei; Sams, Mikko

    2003-09-01

    Memory paradigms are often used in psycho-physiological experiments in order to understand the neural basis underlying cognitive processes. One of the fundamental problems encountered in memory research is how specific and complementary cortical structures interact with each other during episodic encoding and retrieval. A key aspect of the research described below was estimating the coupling of rapid transition processes (in terms of EEG description) which occur in separate cortical areas rather than estimating the routine phase-frequency synchrony in terms of correlation and coherency. It is assumed that these rapid transition processes in the EEG amplitude correspond to the "switching on/off" of brain elemental operations. By making a quantitative estimate of the EEG structural synchrony of alpha-band power between different EEG channels, it was shown that short-term memory has the emergent property of a multiregional neuronal network, and is not the product of strictly hierarchical processing based on convergence through association regions. Moreover, it was demonstrated that the dynamic temporal structure of alpha activity is strongly correlated to the dynamic structure of working memory.

  2. An Outer Arm Dynein Conformational Switch Is Required for Metachronal Synchrony of Motile Cilia in Planaria

    Science.gov (United States)

    Rompolas, Panteleimon; Patel-King, Ramila S.

    2010-01-01

    Motile cilia mediate the flow of mucus and other fluids across the surface of specialized epithelia in metazoans. Efficient clearance of peri-ciliary fluids depends on the precise coordination of ciliary beating to produce metachronal waves. The role of individual dynein motors and the mechanical feedback mechanisms required for this process are not well understood. Here we used the ciliated epithelium of the planarian Schmidtea mediterranea to dissect the role of outer arm dynein motors in the metachronal synchrony of motile cilia. We demonstrate that animals that completely lack outer dynein arms display a significant decline in beat frequency and an inability of cilia to coordinate their oscillations and form metachronal waves. Furthermore, lack of a key mechanosensitive regulatory component (LC1) yields a similar phenotype even though outer arms still assemble in the axoneme. The lack of metachrony was not due simply to a decrease in ciliary beat frequency, as reducing this parameter by altering medium viscosity did not affect ciliary coordination. In addition, we did not observe a significant temporal variability in the beat cycle of impaired cilia. We propose that this conformational switch provides a mechanical feedback system within outer arm dynein that is necessary to entrain metachronal synchrony. PMID:20844081

  3. Egg-hatching synchrony and larval cannibalism in the dock leaf beetle Gastrophysa viridula (Coleoptera: Chrysomelidae).

    Science.gov (United States)

    Kutcherov, Dmitry

    2015-12-01

    Females of leaf beetles and many other herbivorous insects lay eggs in coherent batches. Hatchlings emerge more or less simultaneously and often prey on their late-hatching clutchmates. It is not certain, however, whether this synchrony of hatching is a mere by-product of cannibalism or whether an additional synchronizing factor exists. The following simple experiment was aimed at determining the causal relationship between cannibalism and simultaneous larval emergence. Egg clutches of the dock leaf beetle Gastrophysa viridula were split into two halves. These halves were either kept as coherent groups in two separate dishes or, alternatively, only one half remained whole, whereas the other one was divided into single eggs, each of which was incubated in a separate dish. Halving of a clutch into coherent groups only slightly disrupted the synchrony of emergence. The consequence of individual isolation was more dramatic. Half-clutches consisting of disconnected solitary eggs required almost twice as much time for complete emergence of all larvae, which was significantly more than cannibalism as a sole synchronizing factor might explain. Moreover, survival rates were the same in coherent half-clutches (in the presence of cannibalism) and among isolated individuals. This group effect and the small contribution of cannibalism suggest the existence of an additional synchronizing factor. Possible mechanisms underpinning this phenomenon are discussed. Copyright © 2015 Elsevier GmbH. All rights reserved.

  4. Wall to Wall Optimal Transport

    CERN Document Server

    Hassanzadeh, Pedram; Doering, Charles R

    2013-01-01

    The calculus of variations is employed to find steady divergence-free velocity fields that maximize transport of a tracer between two parallel walls held at fixed concentration for one of two constraints on flow strength: a fixed value of the kinetic energy or a fixed value of the enstrophy. The optimizing flows consist of an array of (convection) cells of a particular aspect ratio Gamma. We solve the nonlinear Euler-Lagrange equations analytically for weak flows and numerically (and via matched asymptotic analysis in the fixed energy case) for strong flows. We report the results in terms of the Nusselt number Nu, a dimensionless measure of the tracer transport, as a function of the Peclet number Pe, a dimensionless measure of the energy or enstrophy of the flow. For both constraints the maximum transport Nu_{MAX}(Pe) is realized in cells of decreasing aspect ratio Gamma_{opt}(Pe) as Pe increases. For the fixed energy problem, Nu_{MAX} \\sim Pe and Gamma_{opt} \\sim Pe^{-1/2}, while for the fixed enstrophy scen...

  5. Auditory Motion Elicits a Visual Motion Aftereffect

    Directory of Open Access Journals (Sweden)

    Christopher C. Berger

    2016-12-01

    Full Text Available The visual motion aftereffect is a visual illusion in which exposure to continuous motion in one direction leads to a subsequent illusion of visual motion in the opposite direction. Previous findings have been mixed with regard to whether this visual illusion can be induced cross-modally by auditory stimuli. Based on research on multisensory perception demonstrating the profound influence auditory perception can have on the interpretation and perceived motion of visual stimuli, we hypothesized that exposure to auditory stimuli with strong directional motion cues should induce a visual motion aftereffect. Here, we demonstrate that horizontally moving auditory stimuli induced a significant visual motion aftereffect—an effect that was driven primarily by a change in visual motion perception following exposure to leftward moving auditory stimuli. This finding is consistent with the notion that visual and auditory motion perception rely on at least partially overlapping neural substrates.

  6. Collective motion

    Science.gov (United States)

    Vicsek, Tamás; Zafeiris, Anna

    2012-08-01

    We review the observations and the basic laws describing the essential aspects of collective motion - being one of the most common and spectacular manifestation of coordinated behavior. Our aim is to provide a balanced discussion of the various facets of this highly multidisciplinary field, including experiments, mathematical methods and models for simulations, so that readers with a variety of background could get both the basics and a broader, more detailed picture of the field. The observations we report on include systems consisting of units ranging from macromolecules through metallic rods and robots to groups of animals and people. Some emphasis is put on models that are simple and realistic enough to reproduce the numerous related observations and are useful for developing concepts for a better understanding of the complexity of systems consisting of many simultaneously moving entities. As such, these models allow the establishing of a few fundamental principles of flocking. In particular, it is demonstrated, that in spite of considerable differences, a number of deep analogies exist between equilibrium statistical physics systems and those made of self-propelled (in most cases living) units. In both cases only a few well defined macroscopic/collective states occur and the transitions between these states follow a similar scenario, involving discontinuity and algebraic divergences.

  7. Perception of Audio-Visual Speech Synchrony in Spanish-Speaking Children with and without Specific Language Impairment

    Science.gov (United States)

    Pons, Ferran; Andreu, Llorenc; Sanz-Torrent, Monica; Buil-Legaz, Lucia; Lewkowicz, David J.

    2013-01-01

    Speech perception involves the integration of auditory and visual articulatory information, and thus requires the perception of temporal synchrony between this information. There is evidence that children with specific language impairment (SLI) have difficulty with auditory speech perception but it is not known if this is also true for the…

  8. Synchrony, compensatory dynamics, and the functional trait basis of phenological diversity in a tropical dry forest tree community

    DEFF Research Database (Denmark)

    Lasky, Jesse R.; Uriarte, Maria; Muscarella, Robert

    2016-01-01

    among species), while biotic interactions can favor synchrony or compensatory dynamics (negative covariance). We used wavelet analyses to examine phenology of community flower and seed production for 45 tree species across multiple temporal scales in a tropical dry forest in Puerto Rico with marked...

  9. Perception of Audio-Visual Speech Synchrony in Spanish-Speaking Children with and without Specific Language Impairment

    Science.gov (United States)

    Pons, Ferran; Andreu, Llorenc; Sanz-Torrent, Monica; Buil-Legaz, Lucia; Lewkowicz, David J.

    2013-01-01

    Speech perception involves the integration of auditory and visual articulatory information, and thus requires the perception of temporal synchrony between this information. There is evidence that children with specific language impairment (SLI) have difficulty with auditory speech perception but it is not known if this is also true for the…

  10. Motion control report

    CERN Document Server

    2013-01-01

    Please note this is a short discount publication. In today's manufacturing environment, Motion Control plays a major role in virtually every project.The Motion Control Report provides a comprehensive overview of the technology of Motion Control:* Design Considerations* Technologies* Methods to Control Motion* Examples of Motion Control in Systems* A Detailed Vendors List

  11. Dynamic response of flexible retaining walls

    Energy Technology Data Exchange (ETDEWEB)

    Younan, A.H.; Veletsos, A.S.; Bandyopadhyay, K.

    1997-01-01

    Making use of an extension of a recently proposed, relatively simple, approximate method of analysis, a critical evaluation is made of the response to horizontal ground shaking of flexible walls retaining a uniform, linear, viscoelastic stratum of constant thickness and semiinfinite extent in the horizontal direction. Both cantilever and top-supported walls are examined. Following a detailed description of the method and of its rate of convergence, comprehensive numerical solutions are presented that elucidate the action of the system and the effects of the various parameters involved. The parameters varied include the flexibility of the wall, the condition of top support, and the characteristics of the ground motion. The effects of both harmonic base motions and an actual earthquake record are examined. Special attention is paid to the effects of long-period, effectively static excitations. A maximum dynamic response is then expressed as the product of the corresponding static response and an appropriate amplification or deamplification factor. The response quantities examined include the displacements of the wall relative to the moving base, the dynamic wall pressures, and the total wall force, base shear and base moment.

  12. Cochlear Responses and Auditory Brainstem Response Functions in Adults with Auditory Neuropathy/ Dys-Synchrony and Individuals with Normal Hearing

    Directory of Open Access Journals (Sweden)

    Zahra Jafari

    2007-06-01

    Full Text Available Background and Aim: Physiologic measures of cochlear and auditory nerve function may be of assis¬tance in distinguishing between hearing disorders due primarily to auditory nerve impairment from those due primarily to cochlear hair cells dysfunction. The goal of present study was to measure of co-chlear responses (otoacoustic emissions and cochlear microphonics and auditory brainstem response in some adults with auditory neuropathy/ dys-synchrony and subjects with normal hearing. Materials and Methods: Patients were 16 adults (32 ears in age range of 14-30 years with auditory neu¬ropathy/ dys-synchrony and 16 individuals in age range of 16-30 years from both sexes. The results of transient otoacoustic emissions, cochlear microphonics and auditory brainstem response measures were compared in both groups and the effects of age, sex, ear and degree of hearing loss were studied. Results: The pure-tone average was 48.1 dB HL in auditory neuropathy/dys-synchrony group and the fre¬quency of low tone loss and flat audiograms were higher among other audiogram's shapes. Transient oto¬acoustic emissions were shown in all auditory neuropathy/dys-synchrony people except two cases and its average was near in both studied groups. The latency and amplitude of the biggest reversed co-chlear microphonics response were higher in auditory neuropathy/dys-synchrony patients than control peo¬ple significantly. The correlation between cochlear microphonics amplitude and degree of hearing loss was not significant, and age had significant effect in some cochlear microphonics measures. Audi-tory brainstem response had no response in auditory neuropathy/dys-synchrony patients even with low stim¬uli rates. Conclusion: In adults with speech understanding worsen than predicted from the degree of hearing loss that suspect to auditory neuropathy/ dys-synchrony, the frequency of low tone loss and flat audiograms are higher. Usually auditory brainstem response is absent in

  13. Quantitative assessment of regional left ventricular motion using endocardial landmarks

    NARCIS (Netherlands)

    C.J. Slager (Cornelis); T.E.H. Hooghoudt (Ton); P.W.J.C. Serruys (Patrick); J.C.H. Schuurbiers (Johan); J.H.C. Reiber (Johan); G.T. Meester (Geert); P.D. Verdouw (Pieter); P.G. Hugenholtz (Paul)

    1986-01-01

    textabstractIn this study the hypothesis is tested that the motion pattern of small anatomic landmarks, recognizable at the left ventricular endocardial border in the contrast angiocardiogram, reflects the motion of the endocardial wall. To verify this, minute metal markers were inserted in the endo

  14. Quantitative assessment of regional left ventricular motion using endocardial landmarks

    NARCIS (Netherlands)

    C.J. Slager (Cornelis); T.E.H. Hooghoudt (Ton); P.W.J.C. Serruys (Patrick); J.C.H. Schuurbiers (Johan); J.H.C. Reiber (Johan); G.T. Meester (Geert); P.D. Verdouw (Pieter); P.G. Hugenholtz (Paul)

    1986-01-01

    textabstractIn this study the hypothesis is tested that the motion pattern of small anatomic landmarks, recognizable at the left ventricular endocardial border in the contrast angiocardiogram, reflects the motion of the endocardial wall. To verify this, minute metal markers were inserted in the endo

  15. Quantitative assessment of regional left ventricular motion using endocardial landmarks

    NARCIS (Netherlands)

    C.J. Slager (Cornelis); T.E.H. Hooghoudt (Ton); P.W.J.C. Serruys (Patrick); J.C.H. Schuurbiers (Johan); J.H.C. Reiber (Johan); G.T. Meester (Geert); P.D. Verdouw (Pieter); P.G. Hugenholtz (Paul)

    1986-01-01

    textabstractIn this study the hypothesis is tested that the motion pattern of small anatomic landmarks, recognizable at the left ventricular endocardial border in the contrast angiocardiogram, reflects the motion of the endocardial wall. To verify this, minute metal markers were inserted in the

  16. Multi-species spawning synchrony within scleractinian coral assemblages in the Red Sea

    Science.gov (United States)

    Bouwmeester, J.; Baird, A. H.; Chen, C. J.; Guest, J. R.; Vicentuan, K. C.; Berumen, M. L.

    2015-03-01

    Early work on coral reproduction in the far northern Red Sea suggested that the spawning times of ecologically abundant species did not overlap, unlike on the Great Barrier Reef where many species spawn with high synchrony. In contrast, recent work in the northern and central Red Sea indicates a high degree of synchrony in the reproductive condition of Acropora species: over 90 % of species sampled in April/May contain mature gametes. However, it has yet to be determined when most Acropora release their gametes. In addition, there is a lack of data for other ecologically important scleractinian species such as merulinids and poritids. Here, we document the date and time of spawning for 51 species in the central Red Sea over three consecutive years, and the month of spawning for an additional 17 species inferred from the presence of mature gametes. Spawning occurs on nights around the full moon, the spawning season lasts at least 4 months from April until July, and observations are consistent with the few other records from the Red Sea. The number of Acropora species spawning was highest in April with 13 species spawning two nights before the full moon in 2011, 13 species spawning on the night of the full moon in 2012, and eight species spawning four nights after the full moon in 2013. The total number of species spawning was high in April, May, and June and involved 15-19 species per month in 2012. Only four species spawned in July 2012. Few regions worldwide have been similarly sampled and include the Philippines, Okinawa in Japan, and Palau, where spawning patterns are very similar to those in the central Red Sea and where corals spawn on nights around the full moon over a period of 3-4 months. In particular, in all four locations, Acropora are among the first species to spawn. Our results add to a growing body of evidence indicating that multi-species spawning synchrony is a feature of all speciose coral assemblages.

  17. Multi-species spawning synchrony within scleractinian coral assemblages in the Red Sea

    KAUST Repository

    Bouwmeester, Jessica

    2014-09-21

    Early work on coral reproduction in the far northern Red Sea suggested that the spawning times of ecologically abundant species did not overlap, unlike on the Great Barrier Reef where many species spawn with high synchrony. In contrast, recent work in the northern and central Red Sea indicates a high degree of synchrony in the reproductive condition of Acropora species: over 90 % of species sampled in April/May contain mature gametes. However, it has yet to be determined when most Acropora release their gametes. In addition, there is a lack of data for other ecologically important scleractinian species such as merulinids and poritids. Here, we document the date and time of spawning for 51 species in the central Red Sea over three consecutive years, and the month of spawning for an additional 17 species inferred from the presence of mature gametes. Spawning occurs on nights around the full moon, the spawning season lasts at least 4 months from April until July, and observations are consistent with the few other records from the Red Sea. The number of Acropora species spawning was highest in April with 13 species spawning two nights before the full moon in 2011, 13 species spawning on the night of the full moon in 2012, and eight species spawning four nights after the full moon in 2013. The total number of species spawning was high in April, May, and June and involved 15–19 species per month in 2012. Only four species spawned in July 2012. Few regions worldwide have been similarly sampled and include the Philippines, Okinawa in Japan, and Palau, where spawning patterns are very similar to those in the central Red Sea and where corals spawn on nights around the full moon over a period of 3–4 months. In particular, in all four locations, Acropora are among the first species to spawn. Our results add to a growing body of evidence indicating that multi-species spawning synchrony is a feature of all speciose coral assemblages.

  18. Sub-millisecond firing synchrony of closely neighboring pyramidal neurons in hippocampal CA1 of rats during delayed non-matching to sample task

    Directory of Open Access Journals (Sweden)

    Susumu Takahashi

    2009-09-01

    Full Text Available Firing synchrony among neurons is thought to play functional roles in several brain regions. In theoretical analyses, firing synchrony among neurons within sub-millisecond precision is feasible to convey information. However, little is known about the occurrence and the functional significance of the sub-millisecond synchrony among closely neighboring neurons in the brain of behaving animals because of a technical issue: spikes simultaneously generated from closely neighboring neurons are overlapped in the extracellular space and are not easily separated. As described herein, using a unique spike sorting technique based on independent component analysis together with extracellular 12-channel multi-electrodes (dodecatrodes, we separated such overlapping spikes and investigated the firing synchrony among closely neighboring pyramidal neurons in the hippocampal CA1 of rats during a delayed non-matching to sample task. Results showed that closely neighboring pyramidal neurons in the hippocampal CA1 can co-fire with sub-millisecond precision. The synchrony generally co-occurred with the firing rate modulation in relation to both internal (retention and comparison and external (stimulus input and motor output events during the task. However, the synchrony occasionally occurred in relation to stimulus inputs even when rate modulation was clearly absent, suggesting that the synchrony is not simply accompanied with firing rate modulation and that the synchrony and the rate modulation might code similar information independently. We therefore conclude that the sub-millisecond firing synchrony in the hippocampus is an effective carrier for propagating information—as represented by the firing rate modulations—to downstream neurons.

  19. Difficulty-related changes in inter-regional neural synchrony are dissociated between target and non-target processing.

    Science.gov (United States)

    Choi, Jeong Woo; Cha, Kwang Su; Choi, Jong Doo; Jung, Ki-Young; Kim, Kyung Hwan

    2015-04-01

    The major purpose of this study was to explore the changes in the local/global gamma-band neural synchronies during target/non-target processing due to task difficulty under an auditory three-stimulus oddball paradigm. Multichannel event-related potentials (ERPs) were recorded from fifteen healthy participants during the oddball task. In addition to the conventional ERP analysis, we investigated the modulations in gamma-band activity (GBA) and inter-regional gamma-band phase synchrony (GBPS) for infrequent target and non-target processing due to task difficulty. The most notable finding was that the difficulty-related changes in inter-regional GBPS (33-35 Hz) at P300 epoch (350-600 ms) completely differed for target and non-target processing. As task difficulty increased, the GBPS significantly reduced for target processing but increased for non-target processing. This result contrasts with the local neural synchrony in gamma-bands, which was not affected by task difficulty. Another major finding was that the spatial patterns of functional connectivity were dissociated for target and non-target processing with regard to the difficult task. The spatial pattern for target processing was compatible with the top-down attention network, whereas that for the non-target corresponded to the bottom-up attention network. Overall, we found that the inter-regional gamma-band neural synchronies during target/non-target processing change significantly with task difficulty and that this change is dissociated between target and non-target processing. Our results indicate that large-scale neural synchrony is more relevant for the difference in information processing between target and non-target stimuli.

  20. Mean-field dispersion-induced spatial synchrony, oscillation and amplitude death, and temporal stability in an ecological model.

    Science.gov (United States)

    Banerjee, Tanmoy; Dutta, Partha Sharathi; Gupta, Anubhav

    2015-05-01

    One of the most important issues in spatial ecology is to understand how spatial synchrony and dispersal-induced stability interact. In the existing studies it is shown that dispersion among identical patches results in spatial synchrony; on the other hand, the combination of spatial heterogeneity and dispersion is necessary for dispersal-induced stability (or temporal stability). Population synchrony and temporal stability are thus often thought of as conflicting outcomes of dispersion. In contrast to the general belief, in this present study we show that mean-field dispersion is conducive to both spatial synchrony and dispersal-induced stability even in identical patches. This simultaneous occurrence of rather conflicting phenomena is governed by the suppression of oscillation states, namely amplitude death (AD) and oscillation death (OD). These states emerge through spatial synchrony of the oscillating patches in the strong-coupling strength. We present an interpretation of the mean-field diffusive coupling in the context of ecology and identify that, with increasing mean-field density, an open ecosystem transforms into a closed ecosystem. We report on the occurrence of OD in an ecological model and explain its significance. Using a detailed bifurcation analysis we show that, depending on the mortality rate and carrying capacity, the system shows either AD or both AD and OD. We also show that the results remain qualitatively the same for a network of oscillators. We identify a new transition scenario between the same type of oscillation suppression states whose geneses differ. In the parameter-mismatched case, we further report on the direct transition from OD to AD through a transcritical bifurcation. We believe that this study will lead to a proper interpretation of AD and OD in ecology, which may be important for the conservation and management of several communities in ecosystems.

  1. Midbrain Synchrony to Envelope Structure Supports Behavioral Sensitivity to Single-Formant Vowel-Like Sounds in Noise.

    Science.gov (United States)

    Henry, Kenneth S; Abrams, Kristina S; Forst, Johanna; Mender, Matthew J; Neilans, Erikson G; Idrobo, Fabio; Carney, Laurel H

    2017-02-01

    Vowels make a strong contribution to speech perception under natural conditions. Vowels are encoded in the auditory nerve primarily through neural synchrony to temporal fine structure and to envelope fluctuations rather than through average discharge rate. Neural synchrony is thought to contribute less to vowel coding in central auditory nuclei, consistent with more limited synchronization to fine structure and the emergence of average-rate coding of envelope fluctuations. However, this hypothesis is largely unexplored, especially in background noise. The present study examined coding mechanisms at the level of the midbrain that support behavioral sensitivity to simple vowel-like sounds using neurophysiological recordings and matched behavioral experiments in the budgerigar. Stimuli were harmonic tone complexes with energy concentrated at one spectral peak, or formant frequency, presented in quiet and in noise. Behavioral thresholds for formant-frequency discrimination decreased with increasing amplitude of stimulus envelope fluctuations, increased in noise, and were similar between budgerigars and humans. Multiunit recordings in awake birds showed that the midbrain encodes vowel-like sounds both through response synchrony to envelope structure and through average rate. Whereas neural discrimination thresholds based on either coding scheme were sufficient to support behavioral thresholds in quiet, only synchrony-based neural thresholds could account for behavioral thresholds in background noise. These results reveal an incomplete transformation to average-rate coding of vowel-like sounds in the midbrain. Model simulations suggest that this transformation emerges due to modulation tuning, which is shared between birds and mammals. Furthermore, the results underscore the behavioral relevance of envelope synchrony in the midbrain for detection of small differences in vowel formant frequency under real-world listening conditions.

  2. DMN Operational Synchrony Relates to Self-Consciousness: Evidence from Patients in Vegetative and Minimally Conscious States.

    Science.gov (United States)

    Fingelkurts, Andrew A; Fingelkurts, Alexander A; Bagnato, Sergio; Boccagni, Cristina; Galardi, Giuseppe

    2012-01-01

    The default mode network (DMN) has been consistently activated across a wide variety of self-related tasks, leading to a proposal of the DMN's role in self-related processing. Indeed, there is limited fMRI evidence that the functional connectivity within the DMN may underlie a phenomenon referred to as self-awareness. At the same time, none of the known studies have explicitly investigated neuronal functional interactions among brain areas that comprise the DMN as a function of self-consciousness loss. To fill this gap, EEG operational synchrony analysis [1, 2] was performed in patients with severe brain injuries in vegetative and minimally conscious states to study the strength of DMN operational synchrony as a function of self-consciousness expression. We demonstrated that the strength of DMN EEG operational synchrony was smallest or even absent in patients in vegetative state, intermediate in patients in minimally conscious state and highest in healthy fully self-conscious subjects. At the same time the process of ecoupling of operations performed by neuronal assemblies that comprise the DMN was highest in patients in vegetative state, intermediate in patients in minimally conscious state and minimal in healthy fully self-conscious subjects. The DMN's frontal EEG operational module had the strongest decrease in operational synchrony strength as a function of selfconsciousness loss, when compared with the DMN's posterior modules. Based on these results it is suggested that the strength of DMN functional connectivity could mediate the strength of self-consciousness expression. The observed alterations similarly occurred across EEG alpha, beta1 and beta2 frequency oscillations. Presented results suggest that the EEG operational synchrony within DMN may provide an objective and accurate measure for the assessment of signs of self-(un)consciousness in these challenging patient populations. This method therefore, may complement the current diagnostic procedures for

  3. Volitional enhancement of firing synchrony and oscillation by neuronal operant conditioning: interaction with neurorehabilitation and brain-machine interface

    Directory of Open Access Journals (Sweden)

    Yoshio eSakurai

    2014-02-01

    Full Text Available In this review, we focus on neuronal operant conditioning in which increments in neuronal activities are directly rewarded without behaviors. We discuss the potential of this approach to elucidate neuronal plasticity for enhancing specific brain functions and its interaction with the progress in neurorehabilitation and brain–machine interfaces. The key to-be-conditioned activities that this paper emphasizes are synchronous and oscillatory firings of multiple neurons that reflect activities of cell assemblies. First, we introduce certain well-known studies on neuronal operant conditioning in which conditioned enhancements of neuronal firing were reported in animals and humans. These studies demonstrated the feasibility of volitional control over neuronal activity. Second, we refer to the recent studies on operant conditioning of synchrony and oscillation of neuronal activities. In particular, we introduce a recent study showing volitional enhancement of oscillatory activity in monkey motor cortex and our study showing selective enhancement of firing synchrony of neighboring neurons in rat hippocampus. Third, we discuss the reasons for emphasizing firing synchrony and oscillation in neuronal operant conditioning, the main reason being that they reflect the activities of cell assemblies, which have been suggested to be basic neuronal codes representing information in the brain. Finally, we discuss the interaction of neuronal operant conditioning with neurorehabilitation and brain–machine interface (BMI. We argue that synchrony and oscillation of neuronal firing are the key activities required for developing both reliable neurorehabilitation and high-performance BMI. Further, we conclude that research of neuronal operant conditioning, neurorehabilitation, BMI, and system neuroscience will produce findings applicable to these interrelated fields, and neuronal synchrony and oscillation can be a common important bridge among all of them.

  4. Direct observation of massless domain wall dynamics in nanostripes with perpendicular magnetic anisotropy.

    Science.gov (United States)

    Vogel, J; Bonfim, M; Rougemaille, N; Boulle, O; Miron, I M; Auffret, S; Rodmacq, B; Gaudin, G; Cezar, J C; Sirotti, F; Pizzini, S

    2012-06-15

    Domain wall motion induced by nanosecond current pulses in nanostripes with perpendicular magnetic anisotropy (Pt/Co/AlO(x)) is shown to exhibit negligible inertia. Time-resolved magnetic microscopy during current pulses reveals that the domain walls start moving, with a constant speed, as soon as the current reaches a constant amplitude, and no or little motion takes place after the end of the pulse. The very low "mass" of these domain walls is attributed to the combination of their narrow width and high damping parameter α. Such a small inertia should allow accurate control of domain wall motion by tuning the duration and amplitude of the current pulses.

  5. Channel Wall Landslides

    Science.gov (United States)

    2005-01-01

    [figure removed for brevity, see original site] The multiple landslides in this VIS image occur along a steep channel wall. Note the large impact crater in the context image. The formation of the crater may have initially weakened that area of the surface prior to channel formation. Image information: VIS instrument. Latitude -2.7, Longitude 324.8 East (35.2 West). 19 meter/pixel resolution. Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time. NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  6. Detection of phase and lag synchrony as an adaptive measure of asymmetric neuronal interactions

    Science.gov (United States)

    Zochowski, Michal

    2006-03-01

    Asymmetric temporal interdependencies between individual neurons and their populations are though to underlie learning and memory formation and can provide information about direction of information transfer in neural systems. We have developed an adaptive measure that detects asymmetries in phase and lag synchrony between activities of individual neurons of synchronized networks. In the first part of the talk I will discuss the properties of the measure on network models of coupled non-linear oscillators and show progression of rapid transitions in temporal patterning in such networks as a function of their topology. In the second part of the talk I will present its application in analysis of normal and pathological neural activity: detection of evolving asymmetry in interactions of hippocampal neurons in freely behaving rats, and characterization of dynamical progression of synchronous seizure-like activity recorded from intact rat hippocampus.

  7. The change in perceptual synchrony between auditory and visual speech after exposure to asynchronous speech.

    Science.gov (United States)

    Tanaka, Akihiro; Asakawa, Kaori; Imai, Hisato

    2011-10-05

    Recent studies have shown that audiovisual synchrony is recalibrated after exposure to asynchronous auditory and visual signals. This temporal recalibration has been shown only under a dual-task situation for speech signals. Here we examined whether the temporal recalibration occurs for audiovisual speech in a single-task situation using an offline adaptation method. In the experiment, participants were exposed to synchronous or asynchronous audiovisual syllables (either congruent or incongruent) for 3 min. The adaptation phase was followed by test trials, in which participants judged whether the auditory or visual stimulus was presented first. Results showed shifts in the point of subjective simultaneity and the sensitivity. Our results suggest that attention to adaptation stimuli is necessary to induce temporal recalibration for speech.

  8. Small rodent population synchrony in western Sweden. Effects of landscape structure

    Directory of Open Access Journals (Sweden)

    J. Loman

    2008-04-01

    Full Text Available Small rodents were captured in two regions in western Sweden. One represents an agricultural landscape were captures were made in 19 small habitat islands and in two small forests. The other represents a forest region were captures were made in four sites in a continuous forest. The captures were made for seven years. There were no clear indications of cyclicity. Within both regions, wood mice captures were in synchrony among sites. For bank voles, this was only true in the forest region and for field voles in the agricultural region. Captures of field voles were too few for analysis in the forest region. Among species, captures were not synchronous in the agricultural region but captures of wood mice and bank voles were synchronous in the forest region. These results suggest a role of landscape structure for the population dynamics of these species, rather than differences in predator function.

  9. Enhanced phase synchrony in the electroencephalograph γ band for musicians while listening to music

    Science.gov (United States)

    Bhattacharya, Joydeep; Petsche, Hellmuth

    2001-07-01

    Multichannel electroencephalograph signals from two broad groups, 10 musicians and 10 nonmusicians, recorded in different states (in resting states or no task condition, with eyes opened and eyes closed, and with two musical tasks, listening to two different pieces of music) were studied. Degrees of phase synchrony in various frequency bands were assessed. No differences in the degree of synchronization in any frequency band were found between the two groups in resting conditions. Yet, while listening to music, significant increases of synchronization were found only in the γ-frequency range (>30 Hz) over large cortical areas for the group of musicians. This high degree of synchronization elicited by music in the group of musicians might be due to their ability to host long-term memory representations of music and mediate access to these stored representations.

  10. Controlling synchrony in oscillatory networks via an act-and-wait algorithm.

    Science.gov (United States)

    Ratas, Irmantas; Pyragas, Kestutis

    2014-09-01

    The act-and-wait control algorithm is proposed to suppress synchrony in globally coupled oscillatory networks in the situation when the simultaneous registration and stimulation of the system is not possible. The algorithm involves the periodic repetition of the registration (wait) and stimulation (act) stages, such that in the first stage the mean field of the free system is recorded in a memory and in the second stage the system is stimulated with the recorded signal. A modified version of the algorithm that takes into account the charge-balanced requirement is considered as well. The efficiency of our algorithm is demonstrated analytically and numerically for globally coupled Landau-Stuart oscillators and synaptically all-to-all coupled FitzHugh-Nagumo as well as Hodgkin-Huxley neurons.

  11. combined spatially and temporally structured walls

    Directory of Open Access Journals (Sweden)

    D. N. Riahi

    1999-01-01

    Full Text Available Benney's theory of evolution of disturbances in shear flows over smooth and flat boundary is extended to study for shear flows over combined spatially and temporally corrugated walls. Perturbation and multiple-scales analyses are employed for the case where both amplitude of the corrugations and the amplitude of wave motion are small. Analyses for instability of modulated mean shear flows with respect to spanwise-periodic disturbance rolls and for the subsequent vortex formation and vortex stability are presented, and the effects of the corrugated walls on the resulting flow and vortices are determined. It is found that particular corrugated walls can originate and control the longitudinal vortices, while some other types of corrugated walls can enhance instability of such vortices.

  12. Additional brain functional network in adults with attention-deficit/hyperactivity disorder: a phase synchrony analysis.

    Directory of Open Access Journals (Sweden)

    Dongchuan Yu

    Full Text Available We develop a method to construct a new type of functional networks by the usage of phase synchrony degree that is different from the widely used Pearson's correlation approach. By a series of very strict statistical tests, we found that there is an additional network in attention-deficit/hyperactivity disorder (ADHD subjects, superimposing the original (normal brain functional network corresponding to healthy controls. The additional network leads to the increase in clustering coefficient, cost, local efficiency, and global efficiency. Our findings are inconsistent with many previous researches (using the Pearson's correlation approach revealing both increased and decreased functional connections between brain regions and many reports revealing that the brain functional networks of ADHD patients have slow information flow and low global efficiency. We also confirm that the additional network in ADHD subjects contains 6 communities, and three of them are associated with emotional control, sensory information integration, and motor control, respectively. Furthermore, we find that there is a pathway connecting the left insula and left anterior cingular gyrus via the frontal gyrus and putamen in the additional network in ADHD subjects. This implies that due to the pathway connecting brain regions in the salience network, the ADHD patients are more sensitive to external stimuli or internal thoughts and are easier to switch to the executive network and hence harder to inhibit. For clinical diagnostic purposes, we apply the k-means clustering method to distinguish ADHD patients with healthy controls at the individual subject level, and obtain a meaningful diagnostic result. More interestingly, we find that the suggested technique using phase synchrony degree to construct functional networks may obtain higher classification accuracy than the method using the Pearson's correlation coefficient.

  13. Content congruency and its interplay with temporal synchrony modulate integration between rhythmic audiovisual streams.

    Science.gov (United States)

    Su, Yi-Huang

    2014-01-01

    Both lower-level stimulus factors (e.g., temporal proximity) and higher-level cognitive factors (e.g., content congruency) are known to influence multisensory integration. The former can direct attention in a converging manner, and the latter can indicate whether information from the two modalities belongs together. The present research investigated whether and how these two factors interacted in the perception of rhythmic, audiovisual (AV) streams derived from a human movement scenario. Congruency here was based on sensorimotor correspondence pertaining to rhythm perception. Participants attended to bimodal stimuli consisting of a humanlike figure moving regularly to a sequence of auditory beat, and detected a possible auditory temporal deviant. The figure moved either downwards (congruently) or upwards (incongruently) to the downbeat, while in both situations the movement was either synchronous with the beat, or lagging behind it. Greater cross-modal binding was expected to hinder deviant detection. Results revealed poorer detection for congruent than for incongruent streams, suggesting stronger integration in the former. False alarms increased in asynchronous stimuli only for congruent streams, indicating greater tendency for deviant report due to visual capture of asynchronous auditory events. In addition, a greater increase in perceived synchrony was associated with a greater reduction in false alarms for congruent streams, while the pattern was reversed for incongruent ones. These results demonstrate that content congruency as a top-down factor not only promotes integration, but also modulates bottom-up effects of synchrony. Results are also discussed regarding how theories of integration and attentional entrainment may be combined in the context of rhythmic multisensory stimuli.

  14. Content congruency and its interplay with temporal synchrony modulate integration between rhythmic audiovisual streams

    Directory of Open Access Journals (Sweden)

    Yi-Huang eSu

    2014-12-01

    Full Text Available Both lower-level stimulus factors (e.g., temporal proximity and higher-level cognitive factors (e.g., content congruency are known to influence multisensory integration. The former can direct attention in a converging manner, and the latter can indicate whether information from the two modalities belongs together. The present research investigated whether and how these two factors interacted in the perception of rhythmic, audiovisual streams derived from a human movement scenario. Congruency here was based on sensorimotor correspondence pertaining to rhythm perception. Participants attended to bimodal stimuli consisting of a humanlike figure moving regularly to a sequence of auditory beat, and detected a possible auditory temporal deviant. The figure moved either downwards (congruently or upwards (incongruently to the downbeat, while in both situations the movement was either synchronous with the beat, or lagging behind it. Greater cross-modal binding was expected to hinder deviant detection. Results revealed poorer detection for congruent than for incongruent streams, suggesting stronger integration in the former. False alarms increased in asynchronous stimuli only for congruent streams, indicating greater tendency for deviant report due to visual capture of asynchronous auditory events. In addition, a greater increase in perceived synchrony was associated with a greater reduction in false alarms for congruent streams, while the pattern was reversed for incongruent ones. These results demonstrate that content congruency as a top-down factor not only promotes integration, but also modulates bottom-up effects of synchrony. Results are also discussed regarding how theories of integration and attentional entrainment may be combined in the context of rhythmic multisensory stimuli.

  15. Phenological synchrony and seasonality of understory Rubiaceae in the Atlantic Forest, Bahia, Brazil

    Directory of Open Access Journals (Sweden)

    Heitor Scarpati Liuth

    2013-03-01

    Full Text Available In tropical forests with low seasonality, climatic variables generally exert a weak influence on the phenology of species. The seasonality of phenophases in closely related taxa can be controlled by phylogenetic constraints in such environments. In this study, our aim was to describe the phenology of Rubiaceae in the understory of the Atlantic Forest in the southern part of Bahia, Brazil, as well as to evaluate the seasonality and phenological synchrony of this family. For two years, we observed 90 individuals belonging to 13 species, in an area of 0.2 ha. Leaf flushing and leaf fall did not demonstrate any seasonality, were continuous for most species and correlated with few of the climatic variables. Flowering was seasonal and correlated positively with all climatic variables. Species exhibited seasonality for this phenophase with high flowering overlap among species of Psychotria, indicating an aggregated pattern for this genus. Fruiting was also seasonal and correlated with all the climatic variables, unripe fruit development peaking at the beginning of the season during which humidity is highest and fruit ripening peaking in the season during which humidity is slightly lower. The vegetative and flowering patterns observed in the study area are commonly seen in other tropical forests. The reproductive seasonality of this family can facilitate the attraction of biotic agents, as postulated in the facilitation hypothesis. Our results demonstrate that climatic variables influenced the phenological patterns observed here, although the high reproductive seasonality and interspecific synchrony, especially in congeneric species, raises the possibility that phylogenetic proximity plays a role in the pattern of the family Rubiaceae.

  16. Synchrony suppression in complex stimulus responses of a biophysical model of the cochlea.

    Science.gov (United States)

    Shamma, S A; Morrish, K A

    1987-05-01

    A minimal biophysical model of the cochlea is used to investigate the validity of the hypothesis that a single compressive nonlinearity at the hair cell level can explain some of the suppression phenomena in cochlear responses to complex stimuli. The dependencies of the model responses on the amplitudes and frequencies of two-tone stimuli resemble in many respects the behavior of the experimental data, and can be traced to explicit biophysical parameters in the model. Most discrepancies between theory and experiment stem from simplifications in parameters of the minimal model that play no direct role in the hypothesis. The analysis and simulations predict further results which, pending experimental verification, may provide a more direct test of the influence of the compressive nonlinearity on the relative amplitudes of the synchronous response components, and hence of its role in synchrony suppression. For instance, regardless of the overall absolute levels of a two-tone stimulus applied to this type of model, the ratio of the amplitudes at the input and the ratio of the corresponding responses at the output remain approximately constant and equal (the output ratio changes by at most 6 dB in favor of the stronger tone). Other nonlinear responses to multitonal stimuli can also be reproduced, such as "spectral edge enhancement" [Horst et al., Peripheral Auditory Mechanisms (Springer, Berlin, 1985)] and some aspects of three-tone suppression [Javel et al., Mechanisms of Hearing (Monash U.P., Australia, 1983)]. In contrast to the complex behavior of suppression with increasing sound intensity and the drastic influence of the compressive nonlinearity on the absolute response measures on the auditory nerve (e.g., average rate and synchrony profiles), the percepts of complex sounds are relatively stable. This suggests that the invariant relative response measures are more likely used in the encoding and CNS extraction of the spectrum of complex stimuli such as speech.

  17. Region-wide synchrony and traveling waves of dengue across eight countries in Southeast Asia.

    Science.gov (United States)

    van Panhuis, Willem G; Choisy, Marc; Xiong, Xin; Chok, Nian Shong; Akarasewi, Pasakorn; Iamsirithaworn, Sopon; Lam, Sai K; Chong, Chee K; Lam, Fook C; Phommasak, Bounlay; Vongphrachanh, Phengta; Bouaphanh, Khamphaphongphane; Rekol, Huy; Hien, Nguyen Tran; Thai, Pham Quang; Duong, Tran Nhu; Chuang, Jen-Hsiang; Liu, Yu-Lun; Ng, Lee-Ching; Shi, Yuan; Tayag, Enrique A; Roque, Vito G; Lee Suy, Lyndon L; Jarman, Richard G; Gibbons, Robert V; Velasco, John Mark S; Yoon, In-Kyu; Burke, Donald S; Cummings, Derek A T

    2015-10-20

    Dengue is a mosquito-transmitted virus infection that causes epidemics of febrile illness and hemorrhagic fever across the tropics and subtropics worldwide. Annual epidemics are commonly observed, but there is substantial spatiotemporal heterogeneity in intensity. A better understanding of this heterogeneity in dengue transmission could lead to improved epidemic prediction and disease control. Time series decomposition methods enable the isolation and study of temporal epidemic dynamics with a specific periodicity (e.g., annual cycles related to climatic drivers and multiannual cycles caused by dynamics in population immunity). We collected and analyzed up to 18 y of monthly dengue surveillance reports on a total of 3.5 million reported dengue cases from 273 provinces in eight countries in Southeast Asia, covering ∼ 10(7) km(2). We detected strong patterns of synchronous dengue transmission across the entire region, most markedly during a period of high incidence in 1997-1998, which was followed by a period of extremely low incidence in 2001-2002. This synchrony in dengue incidence coincided with elevated temperatures throughout the region in 1997-1998 and the strongest El Niño episode of the century. Multiannual dengue cycles (2-5 y) were highly coherent with the Oceanic Niño Index, and synchrony of these cycles increased with temperature. We also detected localized traveling waves of multiannual dengue epidemic cycles in Thailand, Laos, and the Philippines that were dependent on temperature. This study reveals forcing mechanisms that drive synchronization of dengue epidemics on a continental scale across Southeast Asia.

  18. Transcriptional regulation: effects of promoter proximal pausing on speed, synchrony and reliability.

    Directory of Open Access Journals (Sweden)

    Alistair N Boettiger

    2011-05-01

    Full Text Available Recent whole genome polymerase binding assays in the Drosophila embryo have shown that a substantial proportion of uninduced genes have pre-assembled RNA polymerase-II transcription initiation complex (PIC bound to their promoters. These constitute a subset of promoter proximally paused genes for which mRNA elongation instead of promoter access is regulated. This difference can be described as a rearrangement of the regulatory topology to control the downstream transcriptional process of elongation rather than the upstream transcriptional initiation event. It has been shown experimentally that genes with the former mode of regulation tend to induce faster and more synchronously, and that promoter-proximal pausing is observed mainly in metazoans, in accord with a posited impact on synchrony. However, it has not been shown whether or not it is the change in the regulated step per se that is causal. We investigate this question by proposing and analyzing a continuous-time Markov chain model of PIC assembly regulated at one of two steps: initial polymerase association with DNA, or release from a paused, transcribing state. Our analysis demonstrates that, over a wide range of physical parameters, increased speed and synchrony are functional consequences of elongation control. Further, we make new predictions about the effect of elongation regulation on the consistent control of total transcript number between cells. We also identify which elements in the transcription induction pathway are most sensitive to molecular noise and thus possibly the most evolutionarily constrained. Our methods produce symbolic expressions for quantities of interest with reasonable computational effort and they can be used to explore the interplay between interaction topology and molecular noise in a broader class of biochemical networks. We provide general-purpose code implementing these methods.

  19. Evidence for climate-driven synchrony of marine and terrestrial ecosystems in northwest Australia.

    Science.gov (United States)

    Ong, Joyce J L; Rountrey, Adam N; Zinke, Jens; Meeuwig, Jessica J; Grierson, Pauline F; O'Donnell, Alison J; Newman, Stephen J; Lough, Janice M; Trougan, Mélissa; Meekan, Mark G

    2016-08-01

    The effects of climate change are difficult to predict for many marine species because little is known of their response to climate variations in the past. However, long-term chronologies of growth, a variable that integrates multiple physical and biological factors, are now available for several marine taxa. These allow us to search for climate-driven synchrony in growth across multiple taxa and ecosystems, identifying the key processes driving biological responses at very large spatial scales. We hypothesized that in northwest (NW) Australia, a region that is predicted to be strongly influenced by climate change, the El Niño Southern Oscillation (ENSO) phenomenon would be an important factor influencing the growth patterns of organisms in both marine and terrestrial environments. To test this idea, we analyzed existing growth chronologies of the marine fish Lutjanus argentimaculatus, the coral Porites spp. and the tree Callitris columellaris and developed a new chronology for another marine fish, Lethrinus nebulosus. Principal components analysis and linear model selection showed evidence of ENSO-driven synchrony in growth among all four taxa at interannual time scales, the first such result for the Southern Hemisphere. Rainfall, sea surface temperatures, and sea surface salinities, which are linked to the ENSO system, influenced the annual growth of fishes, trees, and corals. All four taxa had negative relationships with the Niño-4 index (a measure of ENSO status), with positive growth patterns occurring during strong La Niña years. This finding implies that future changes in the strength and frequency of ENSO events are likely to have major consequences for both marine and terrestrial taxa. Strong similarities in the growth patterns of fish and trees offer the possibility of using tree-ring chronologies, which span longer time periods than those of fish, to aid understanding of both historical and future responses of fish populations to climate variation.

  20. EARLY LIFE-HISTORY OF MELAMPUS AND THE SIGNIFICANCE OF SEMILUNAR SYNCHRONY.

    Science.gov (United States)

    Russell-Hunter, W D; Apley, Martyn L; Hunter, R Douglas

    1972-12-01

    1. The salt-marsh pulmonate snail, Melampus bidentatus, is placed in the Ellobiidae which family encompasses the most primitive of living Pulmonata and is regarded as not far removed from the ancestral stem-group of both modern land snails and freshwater pulmonates. Inhabiting the higher levels of salt marshes. Melampus is "amphibious": although an air-breather with a gill-less vascularized mantle-cavity functioning as a lung, if retains an archetypic pattern of reproduction with small eggs and a free-swimming veliger larva. 2. Field and laboratory studies over several years (based on natural populations at Little Sippewisset, Cape Cod, Massachusetts) have shown that egg-laying, hatching, and larval settlement are each confined to cycles of about four days in phase with the spring high tides. Adaptively such semilunar synchronies ensure that these processes occur only during the 2.3% to 4% of each month when the Melampus habitat in the upper 12% of the intertidal zone is bathed by seawater. 3. The annual reproductive period extends from late May or early June through early July. with either three or four cycles of egg-laying occurring at two-week intervals in phase with the tides of new and of full moon. Synchrony of egg-laying (and of the patterned aggregation and copulation which precede it) is obligate. Stocks of Melampus brought into the laboratory in spring will maintain the same semilunar rhythm of reproductive behavior during the summer period. 4. Eggs are small (about 109 ng organic carbon) and are laid in gelatinous egg-masses averaging 850 eggs. Mean numerical fecundity is 33,150 eggs per snail per year. For most freshwater pulmonates fecundity would lie in the range 8-800 eggs per snail per year. At 18° C, development to a well-differentiated and active veliger within the egg-shell takes 11 days. 5. Hatching shows semilunar synchrony in the field: enormous numbers of newly hatched veligers can be collected on the flood of appropriate spring tides. A

  1. Brownian motion as a new probe of wettability

    Science.gov (United States)

    Mo, Jianyong; Simha, Akarsh; Raizen, Mark G.

    2017-04-01

    Understanding wettability is crucial for optimizing oil recovery, semiconductor manufacturing, pharmaceutical industry, and electrowetting. In this letter, we study the effects of wettability on Brownian motion. We consider the cases of a sphere in an unbounded fluid medium, as well as a sphere placed in the vicinity of a plane wall. For the first case, we show the effects of wettability on the statistical properties of the particles' motion, such as velocity autocorrelation, velocity, and thermal force power spectra over a large range of time scales. We also propose a new method to measure wettability based on the particles' Brownian motion. In addition, we compare the boundary effects on Brownian motion imposed by both no-slip and perfect-slip flat walls. We emphasize the surprising boundary effects on Brownian motion imposed by a perfect-slip wall in the parallel direction, such as a higher particle mobility parallel to a perfect flat wall compared to that in the absence of the wall, as well as compared to a particle near a no-slip flat wall.

  2. Gravitational field of spherical domain wall in higher dimension

    Indian Academy of Sciences (India)

    Farook Rahaman; Mehedi Kalam

    2002-01-01

    An exact solution of Einstein’s equations is found describing the gravitational field of a spherical domain wall with nonvanishing stress component in the direction perpendicular to the plane of the wall. Also we have studied the motion of test particle around the domain wall.

  3. Existing Motor State Is Favored at the Expense of New Movement during 13-35 Hz Oscillatory Synchrony in the Human Corticospinal System

    National Research Council Canada - National Science Library

    Gilbertson, Thomas; Lalo, Elodie; Doyle, Louise; Di Lazzaro, Vincenzo; Cioni, Beatrice; Brown, Peter

    2005-01-01

    .... Three experiments were performed. First, healthy subjects were instructed to make reaction time movements of the outstretched index finger in response to imperative cues triggered by transient increases in corticospinal synchrony...

  4. Motion in radiotherapy

    DEFF Research Database (Denmark)

    Korreman, Stine Sofia

    2012-01-01

    This review considers the management of motion in photon radiation therapy. An overview is given of magnitudes and variability of motion of various structures and organs, and how the motion affects images by producing artifacts and blurring. Imaging of motion is described, including 4DCT and 4DPET...

  5. Neural dynamics in a model of the thalamocortical system. II. The role of neural synchrony tested through perturbations of spike timing.

    Science.gov (United States)

    Lumer, E D; Edelman, G M; Tononi, G

    1997-01-01

    Activity in the mammalian thalamocortical system is often accompanied by a synchronous discharge of cortical and thalamic neurons. Although many functions have been attributed to such synchronous firing, it is not known whether or how synchrony of firing per se affects thalamocortical operations. Direct experimental tests of the consequences of neuronal synchronization in vivo are hard to carry out, whereas theoretical studies based on single-neuron models cannot reveal the effects of synchrony at the system level. To overcome these limitations, we have used a perturbational approach to test the causal efficacy of synchrony per se in large-scale simulations of the thalamocortical system. The test consists of selectively disrupting firing synchrony by 'jittering' the timing of action potentials in the simulations and determining whether firing rates are modified by this perturbation. The simulations are based in detail on the known anatomy and physiology of the thalamocortical-visual system of the cat, and have been shown in a companion paper to produce episodes of fast synchronous activity at multiple levels. By carrying out the perturbation analysis, we established that neurons can have long membrane time constants (8-16 ms) and balanced synaptic activations, and yet function collectively in such a way that synchrony within a time window of 4 ms significantly affects the rates and selectivity of the responses to visual stimuli. The simulations also revealed a complex interplay, at the network level, between synchrony of firing and rate of firing. The dynamic consequences of firing synchrony were most evident when spike jittering was applied to specific polysynaptic loops involving corticocortical and corticothalamic connections. These results support the view that firing synchrony within thalamocortical and corticocortical loops plays a causal role in the cooperative and competitive neural interactions that produce pattern-selective responses in the cortex.

  6. Comparative study of Trombe wall, water wall and trans wall

    Energy Technology Data Exchange (ETDEWEB)

    Sodha, M.S.; Bansal, N.K.; Singh, S.; Ram, S.; Annamalai, M.; Iyer, M.V.; Nirmala, K.A.; Venkatesh, P.; Prasad, C.R.; Subramani, C.

    1982-01-01

    The thermal performances of three systems viz. Trombe wall: (1) without; and (2) with vents (forced air circulation), water wall and Transwall have been studied analytically interms of heat flux entering the living space (Maintained at 20/sup 0/C) corresponding to the meteriological data on January 19, 1981 at New Delhi (India), a typical cold winter day. Subsequent parametric studies using the simulation indicated that the Transwall system is the more efficient system for the passive heating of buildings.

  7. Detectability of motions in AAA with ECG-gated CTA: A quantitative study

    NARCIS (Netherlands)

    Klein, Almar; Oostveen, Luuk J.; Greuter, Marcel J.W.; Hoogeveen, Yvonne; Schultze Kool, Leo J.; Slump, Cornelis H.; Renema, W. Klaas Jan

    2009-01-01

    Purpose: ECG-gated CT enables the visualization of motions caused by the beating of the heart. Although ECG gating is frequently used in cardiac CT imaging, this technique is also very promising for evaluating vessel wall motion of the aortic artery and the motions of (stent grafts inside) abdominal

  8. Detectability of motions in AAA with ECG-gated CTA: a quantitative study.

    NARCIS (Netherlands)

    Klein, A.; Oostveen, L.J.; Greuter, M.J.; Hoogeveen, Y.L.; Kool, L.J.; Slump, C.H.; Renema, W.K.J.

    2009-01-01

    PURPOSE: ECG-gated CT enables the visualization of motions caused by the beating of the heart. Although ECG gating is frequently used in cardiac CT imaging, this technique is also very promising for evaluating vessel wall motion of the aortic artery and the motions of (stent grafts inside) abdominal

  9. Detectability of motions in AAA with ECG-gated CTA : A quantitative study

    NARCIS (Netherlands)

    Klein, Almar; Oostveen, Luuk J.; Greuter, Marcel J. W.; Hoogeveen, Yvonne; Kool, Leo J. Schultze; Slump, Cornelis H.; Renema, W. Klaas Jan

    2009-01-01

    Purpose: ECG-gated CT enables the visualization of motions caused by the beating of the heart. Although ECG gating is frequently used in cardiac CT imaging, this technique is also very promising for evaluating vessel wall motion of the aortic artery and the motions of (stent grafts inside) abdominal

  10. A new approach for the quantification of synchrony of multivariate non-stationary psychophysiological variables during emotion eliciting stimuli

    Directory of Open Access Journals (Sweden)

    Augustin eKelava

    2015-01-01

    Full Text Available Emotion eliciting situations are accompanied by reactions on multiple response variables on subjective, physiological, and behavioral levels. The quantification of the overall simultaneous synchrony of psychophysiological reactions, plays a major role in emotion theories and has received increasing attention in recent research. From a psychometric perspective, the reactions represent multivariate non-stationary intra-individual time series. In this paper, we present a new time-frequency based latent variable approach for the quantification of the synchrony of the responses. The approach is applied to empirical data collected during an emotion eliciting situation. The results are compared with a complementary inter-individual approach of Hsieh et al. (2011. Finally, the proposed approach is discussed in the context of emotion theories, and possible future applications and limitations are provided.

  11. Semantic congruency but not temporal synchrony enhances long-term memory performance for audio-visual scenes.

    Science.gov (United States)

    Meyerhoff, Hauke S; Huff, Markus

    2016-04-01

    Human long-term memory for visual objects and scenes is tremendous. Here, we test how auditory information contributes to long-term memory performance for realistic scenes. In a total of six experiments, we manipulated the presentation modality (auditory, visual, audio-visual) as well as semantic congruency and temporal synchrony between auditory and visual information of brief filmic clips. Our results show that audio-visual clips generally elicit more accurate memory performance than unimodal clips. This advantage even increases with congruent visual and auditory information. However, violations of audio-visual synchrony hardly have any influence on memory performance. Memory performance remained intact even with a sequential presentation of auditory and visual information, but finally declined when the matching tracks of one scene were presented separately with intervening tracks during learning. With respect to memory performance, our results therefore show that audio-visual integration is sensitive to semantic congruency but remarkably robust against asymmetries between different modalities.

  12. A new method for evaluating flowering synchrony to support the temporal isolation of genetically modified crops from their wild relatives.

    Science.gov (United States)

    Ohigashi, Kentaro; Mizuguti, Aki; Yoshimura, Yasuyuki; Matsuo, Kazuhito; Miwa, Tetsuhisa

    2014-01-01

    Hybridization between crops and their wild relatives potentially threatens the genetic identity of the wild plants, particularly in the case of genetically modified crops. Only a few studies have examined the use of temporal isolation to prevent hybridization, and the indices used in those studies, (e.g., the days of flowering overlap), are not precise to evaluate the degree of synchrony in flowering. Here we propose a flowering similarity index that can compare the degree of flowering synchrony between two relevant species and measure the efficiency of temporal isolation. The results showed that the flowering similarity index predicts the likelihood of hybridization much better than the number of flowering-overlap days, regardless of different flowering patterns among cultivars. Thus, temporal isolation of flowering or flowering asynchrony is the most effective means in preventing hybridization between crops and their wild relatives.

  13. Variation in Population Synchrony in a Multi-Species Seabird Community: Response to Changes in Predator Abundance.

    Directory of Open Access Journals (Sweden)

    Gail S Robertson

    Full Text Available Ecologically similar sympatric species, subject to typical environmental conditions, may be expected to exhibit synchronous temporal fluctuations in demographic parameters, while populations of dissimilar species might be expected to show less synchrony. Previous studies have tested for synchrony in different populations of single species, and those including data from more than one species have compared fluctuations in only one demographic parameter. We tested for synchrony in inter-annual changes in breeding population abundance and productivity among four tern species on Coquet Island, northeast England. We also examined how manipulation of one independent environmental variable (predator abundance influenced temporal changes in ecologically similar and dissimilar tern species. Changes in breeding abundance and productivity of ecologically similar species (Arctic Sterna paradisaea, Common S. hirundo and Roseate Terns S. dougallii were synchronous with one another over time, but not with a species with different foraging and breeding behaviour (Sandwich Terns Thalasseus sandvicensis. With respect to changes in predator abundance, there was no clear pattern. Roseate Tern abundance was negatively correlated with that of large gulls breeding on the island from 1975 to 2013, while Common Tern abundance was positively correlated with number of large gulls, and no significant correlations were found between large gull and Arctic and Sandwich Tern populations. Large gull abundance was negatively correlated with productivity of Arctic and Common Terns two years later, possibly due to predation risk after fledging, while no correlation with Roseate Tern productivity was found. The varying effect of predator abundance is most likely due to specific differences in the behaviour and ecology of even these closely-related species. Examining synchrony in multi-species assemblages improves our understanding of how whole communities react to long-term changes

  14. Variation in Population Synchrony in a Multi-Species Seabird Community: Response to Changes in Predator Abundance.

    Science.gov (United States)

    Robertson, Gail S; Bolton, Mark; Morrison, Paul; Monaghan, Pat

    2015-01-01

    Ecologically similar sympatric species, subject to typical environmental conditions, may be expected to exhibit synchronous temporal fluctuations in demographic parameters, while populations of dissimilar species might be expected to show less synchrony. Previous studies have tested for synchrony in different populations of single species, and those including data from more than one species have compared fluctuations in only one demographic parameter. We tested for synchrony in inter-annual changes in breeding population abundance and productivity among four tern species on Coquet Island, northeast England. We also examined how manipulation of one independent environmental variable (predator abundance) influenced temporal changes in ecologically similar and dissimilar tern species. Changes in breeding abundance and productivity of ecologically similar species (Arctic Sterna paradisaea, Common S. hirundo and Roseate Terns S. dougallii) were synchronous with one another over time, but not with a species with different foraging and breeding behaviour (Sandwich Terns Thalasseus sandvicensis). With respect to changes in predator abundance, there was no clear pattern. Roseate Tern abundance was negatively correlated with that of large gulls breeding on the island from 1975 to 2013, while Common Tern abundance was positively correlated with number of large gulls, and no significant correlations were found between large gull and Arctic and Sandwich Tern populations. Large gull abundance was negatively correlated with productivity of Arctic and Common Terns two years later, possibly due to predation risk after fledging, while no correlation with Roseate Tern productivity was found. The varying effect of predator abundance is most likely due to specific differences in the behaviour and ecology of even these closely-related species. Examining synchrony in multi-species assemblages improves our understanding of how whole communities react to long-term changes in the

  15. Effects of primary PCI and facilitated PCI on myocardial viability and ventricular systolic synchrony in acute myocardial infarction patients

    Institute of Scientific and Technical Information of China (English)

    谷新顺; 傅向华; 马宁

    2003-01-01

    Effects of primary PCI and facilitated PCI on myocardial viability and ventricular systolic synchrony in acute myocardial infarction patients!石家庄050000$河北医科大学第二医院@谷新顺 !石家庄050000$河北医科大学第二医院@傅向华 !石家庄050000$河北医科大学第二医院@马宁

  16. Influenza Epidemics in Iceland Over 9 Decades: Changes in Timing and Synchrony With the United States and Europe

    OpenAIRE

    Weinberger, Daniel M.; Krause, Tyra Grove; Mølbak, Kåre; Cliff, Andrew; Briem, Haraldur; Viboud, Cécile; Gottfredsson, Magnus

    2012-01-01

    Influenza epidemics exhibit a strongly seasonal pattern, with winter peaks that occur with similar timing across temperate areas of the Northern Hemisphere. This synchrony could be influenced by population movements, environmental factors, host immunity, and viral characteristics. The historical isolation of Iceland and subsequent increase in international contacts make it an ideal setting to study epidemic timing. The authors evaluated changes in the timing and regional syn...

  17. Scaling law for bubbles rising near vertical walls

    Science.gov (United States)

    Dabiri, Sadegh; Bhuvankar, Pramod

    2016-06-01

    This paper examines the rising motion of a layer of gas bubbles next to a vertical wall in a liquid in the presence of an upward flow parallel to the wall to help with the understanding of the fluid dynamics in a bubbly upflow in vertical channels. Only the region near the wall is simulated with an average pressure gradient applied to the domain that balances the weight of the liquid phase. The upward flow is created by the rising motion of the bubbles. The bubbles are kept near the wall by the lateral lift force acting on them as a result of rising in the shear layer near the wall. The rise velocity of the bubbles sliding on the wall and the average rise velocity of the liquid depend on three dimensionless parameters, Archimedes number, Ar, Eötvös number, Eo, and the average volume fraction of bubbles on the wall. In the limit of small Eo, bubbles are nearly spherical and the dependency on Eo becomes negligible. In this limit, the scaling of the liquid Reynolds number with Archimedes number and the void fraction is presented. A scaling argument is presented based on viscous dissipation analysis that matches the numerical findings. Viscous dissipation rates are found to be high in a thin film region between the bubble and the wall. A scaling of the viscous dissipation and steady state film thickness between the bubble and the wall with Archimedes number is presented.

  18. Wall-induced path variation of a large deformable rising bubble

    Science.gov (United States)

    Park, Hyungmin; Jeong, Hyeonju

    2014-11-01

    In the present study, we experimentally investigate the wall-induced path variation of a large deformable bubble (Re ~ O (103)) rising near a vertical wall in quiescent water. To change the wall effect, we consider different wall materials (acrylic, PTFE and sponge) and vary the initial distance between the bubble and the wall. Depending on the conditions, various motions like a periodic bouncing, sliding, migrating away, and non-periodic oscillation without collisions are captured. Analysis on the energy balance shows that, contrary to a low- Re bubble, the surface deformation plays a great role in bubble's rising behaviour. Especially, across the bubble-wall collision, the excessive surface energy compensates the deficit of kinetic energy, which enables the bubble to maintain a constant bouncing kinematics, despite the wall effect. The wall effect, appearing as a energy loss, decreases as the distance to the wall increases. Compared to the no-slip surface, the hydrophobic surface enhances or reduces the wall effect with the wall distance, whereas the porous surface reduces the energy loss due to the wall. The dependence of near-wall bubble motion on a wall configuration may give us an idea about how to predict or model the near-wall gas void-fraction. Supported by the NRF Programs (NRF-2012M2A8A4055647, NRF-2013R1A1A1008373) of Korean government.

  19. Domain Walls on Singularities

    CERN Document Server

    Halyo, Edi

    2009-01-01

    We describe domain walls that live on $A_2$ and $A_3$ singularities. The walls are BPS if the singularity is resolved and non--BPS if it is deformed and fibered. We show that these domain walls may interpolate between vacua that support monopoles and/or vortices.

  20. The Lamportian cell wall

    Energy Technology Data Exchange (ETDEWEB)

    Keiliszewski, M.; Lamport, D. (Michigan State Univ. Plant Research Lab., East Lansing (United States))

    1991-05-01

    The Lamportian Warp-Weft hypothesis suggests a cellulose-extensin interpenetrating network where extensin mechanically couples the load-bearing cellulose microfibrils in a wall matrix that is best described as a microcomposite. This model is based on data gathered from the extensin-rich walls of tomato and sycamore cell suspension culture, wherein extensin precursors are insolubilized into the wall by undefined crosslinks. The authors recent work with cell walls isolated from intact tissue as well as walls from suspension cultured cells of the graminaceous monocots maize and rice, the non-graminaceous monocot asparagus, the primitive herbaceous dicot sugar beet, and the gymnosperm Douglas Fir indicate that although extensins are ubiquitous to all plant species examined, they are not the major structural protein component of most walls examined. Amino acid analyses of intact and HF-treated walls shows a major component neither an HRGP, nor directly comparable to the glycine-rich wall proteins such as those associated with seed coat walls or the 67 mole% glycine-rich proteins cloned from petunia and soybean. Clearly, structural wall protein alternatives to extensin exist and any cell wall model must take that into account. If we assume that extracellular matrices are a priori network structures, then new Hypless' structural proteins in the maize cell wall raise questions about the sort of network these proteins create: the kinds of crosslinks involved; how they are formed; and the roles played by the small amounts of HRGPs.

  1. Halogenation of microcapsule walls

    Science.gov (United States)

    Davis, T. R.; Schaab, C. K.; Scott, J. C.

    1972-01-01

    Procedure for halogenation of confining walls of both gelatin and gelatin-phenolic resin capsules is similar to that used for microencapsulation. Ten percent halogen content renders capsule wall nonburning; any higher content enhances flame-retardant properties of selected internal phase material. Halogenation decreases permeability of wall material to encapsulated materials.

  2. Spin torque and interactions in ferromagnetic semiconductor domain walls

    Science.gov (United States)

    Golovatski, Elizabeth Ann

    The motion of domain walls due to the spin torque generated by coherent carrier transport is of considerable interest for the development of spintronic devices. We model the charge and spin transport through domain walls in ferromagnetic semiconductors for various systems. With an appropriate model Hamiltonian for the spin-dependent potential, we calculate wavefunctions inside the domain walls which are then used to calculate transmission and reflection coefficients, which are then in turn used to calculate current and spin torque. Starting with a simple approximation for the change in magnetization inside the domain wall, and ending with a sophisticated transfer matrix method, we model the common pi wall, the less-studied 2pi wall, and a system of two pi walls separated by a variable distance. We uncover an interesting width dependence on the transport properties of the domain wall. 2pi walls in particular, have definitive maximums in resistance and spin torque for certain domain wall widths that can be seen as a function of the spin mistracking in the system---when the spins are either passing straight through the domain wall (narrow walls) or adiabatically following the magnetization (wide walls), the resistance is low as transmission is high. In the intermediate region, there is room for the spins to rotate their magnetization, but not necessarily all the way through a 360 degree rotation, leading to reflection and resistance. We also calculate that there are widths for which the total velocity of a 2pi wall is greater than that of a same-sized pi wall. In the double-wall system, we model how the system reacts to changes in the separation of the domain walls. When the domain walls are far apart, they act as a spin-selective resonant double barrier, with sharp resonance peaks in the transmission profile. Brought closer and closer together, the number and sharpness of the peaks decrease, the spectrum smooths out, and the domain walls brought together have a

  3. Long-term meditation training induced changes in the operational synchrony of default mode network modules during a resting state.

    Science.gov (United States)

    Fingelkurts, Andrew A; Fingelkurts, Alexander A; Kallio-Tamminen, Tarja

    2016-02-01

    Using theoretical analysis of self-consciousness concept and experimental evidence on the brain default mode network (DMN) that constitutes the neural signature of self-referential processes, we hypothesized that the anterior and posterior subnets comprising the DMN should show differences in their integrity as a function of meditation training. Functional connectivity within DMN and its subnets (measured by operational synchrony) has been measured in ten novice meditators using an electroencephalogram (EEG) recording in a pre-/post-meditation intervention design. We have found that while the whole DMN was clearly suppressed, different subnets of DMN responded differently after 4 months of meditation training: The strength of EEG operational synchrony in the right and left posterior modules of the DMN decreased in resting post-meditation condition compared to a pre-meditation condition, whereas the frontal DMN module on the contrary exhibited an increase in the strength of EEG operational synchrony. These findings combined with published data on functional-anatomic heterogeneity within the DMN and on trait subjective experiences commonly found following meditation allow us to propose that the first-person perspective and the sense of agency (the witnessing observer) are presented by the frontal DMN module, while the posterior modules of the DMN are generally responsible for the experience of the continuity of 'I' as embodied and localized within bodily space. Significance of these findings is discussed.

  4. Influenza epidemics in Iceland over 9 decades: changes in timing and synchrony with the United States and Europe.

    Science.gov (United States)

    Weinberger, Daniel M; Krause, Tyra Grove; Mølbak, Kåre; Cliff, Andrew; Briem, Haraldur; Viboud, Cécile; Gottfredsson, Magnus

    2012-10-01

    Influenza epidemics exhibit a strongly seasonal pattern, with winter peaks that occur with similar timing across temperate areas of the Northern Hemisphere. This synchrony could be influenced by population movements, environmental factors, host immunity, and viral characteristics. The historical isolation of Iceland and subsequent increase in international contacts make it an ideal setting to study epidemic timing. The authors evaluated changes in the timing and regional synchrony of influenza epidemics using mortality and morbidity data from Iceland, North America, and Europe during the period from 1915 to 2007. Cross-correlations and wavelet analyses highlighted 2 major changes in influenza epidemic patterns in Iceland: first was a shift from nonseasonal epidemics prior to the 1930s to a regular winter-seasonal pattern, and second was a change in the early 1990s when a 1-month lag between Iceland and the United States and Europe was no longer detectable with monthly data. There was a moderate association between increased synchrony and the number of foreign visitors to Iceland, providing a plausible explanation for the second shift in epidemic timing. This suggests that transportation might have a minor effect on epidemic timing, but efforts to restrict air travel during influenza epidemics would likely have a limited impact, even for island populations.

  5. The spatial structure and temporal synchrony of water quality in stream networks

    Science.gov (United States)

    Abbott, Benjamin; Gruau, Gerard; Zarneske, Jay; Barbe, Lou; Gu, Sen; Kolbe, Tamara; Thomas, Zahra; Jaffrezic, Anne; Moatar, Florentina; Pinay, Gilles

    2017-04-01

    To feed nine billion people in 2050 while maintaining viable aquatic ecosystems will require an understanding of nutrient pollution dynamics throughout stream networks. Most regulatory frameworks such as the European Water Framework Directive and U.S. Clean Water Act, focus on nutrient concentrations in medium to large rivers. This strategy is appealing because large rivers integrate many small catchments and total nutrient loads drive eutrophication in estuarine and oceanic ecosystems. However, there is growing evidence that to understand and reduce downstream nutrient fluxes we need to look upstream. While headwater streams receive the bulk of nutrients in river networks, the relationship between land cover and nutrient flux often breaks down for small catchments, representing an important ecological unknown since 90% of global stream length occurs in catchments smaller than 15 km2. Though continuous monitoring of thousands of small streams is not feasible, what if we could learn what we needed about where and when to implement monitoring and conservation efforts with periodic sampling of headwater catchments? To address this question we performed repeat synoptic sampling of 56 nested catchments ranging in size from 1 to 370 km2 in western France. Spatial variability in carbon and nutrient concentrations decreased non-linearly as catchment size increased, with thresholds in variance for organic carbon and nutrients occurring between 36 and 68 km2. While it is widely held that temporal variance is higher in smaller streams, we observed consistent temporal variance across spatial scales and the ranking of catchments based on water quality showed strong synchrony in the water chemistry response to seasonal variation and hydrological events. We used these observations to develop two simple management frameworks. The subcatchment leverage concept proposes that mitigation and restoration efforts are more likely to succeed when implemented at spatial scales expressing

  6. Electric-field-driven dynamics of magnetic domain walls in magnetic nanowires patterned on ferroelectric domains

    OpenAIRE

    Van de Wiele, Ben; Leliaert, Jonathan; Franke, Kévin; van Dijken, Sebastiaan

    2016-01-01

    Strong coupling of magnetic domain walls onto straight ferroelastic boundaries of a ferroelectric layer enables full and reversible electric-field control of magnetic domain wall motion. In this paper, the dynamics of this new driving mechanism is analyzed using micromagnetic simulations. We show that transverse domain walls with a near-180° spin structure are stabilized in magnetic nanowires and that electric fields can move these walls with high velocities. Above a critical velocity, which ...

  7. The importance of synchrony and temporal order of visual and tactile input for illusory limb ownership experiences - an FMRI study applying virtual reality.

    Directory of Open Access Journals (Sweden)

    Robin Bekrater-Bodmann

    Full Text Available In the so-called rubber hand illusion, synchronous visuotactile stimulation of a visible rubber hand together with one's own hidden hand elicits ownership experiences for the artificial limb. Recently, advanced virtual reality setups were developed to induce a virtual hand illusion (VHI. Here, we present functional imaging data from a sample of 25 healthy participants using a new device to induce the VHI in the environment of a magnetic resonance imaging (MRI system. In order to evaluate the neuronal robustness of the illusion, we varied the degree of synchrony between visual and tactile events in five steps: in two conditions, the tactile stimulation was applied prior to visual stimulation (asynchrony of -300 ms or -600 ms, whereas in another two conditions, the tactile stimulation was applied after visual stimulation (asynchrony of +300 ms or +600 ms. In the fifth condition, tactile and visual stimulation was applied synchronously. On a subjective level, the VHI was successfully induced by synchronous visuotactile stimulation. Asynchronies between visual and tactile input of ±300 ms did not significantly diminish the vividness of illusion, whereas asynchronies of ±600 ms did. The temporal order of visual and tactile stimulation had no effect on VHI vividness. Conjunction analyses of functional MRI data across all conditions revealed significant activation in bilateral ventral premotor cortex (PMv. Further characteristic activation patterns included bilateral activity in the motion-sensitive medial superior temporal area as well as in the bilateral Rolandic operculum, suggesting their involvement in the processing of bodily awareness through the integration of visual and tactile events. A comparison of the VHI-inducing conditions with asynchronous control conditions of ±600 ms yielded significant PMv activity only contralateral to the stimulation site. These results underline the temporal limits of the induction of limb ownership related to

  8. A Wall of Funnels Concentrates Swimming Bacteria▿

    Science.gov (United States)

    Galajda, Peter; Keymer, Juan; Chaikin, Paul; Austin, Robert

    2007-01-01

    Randomly moving but self-propelled agents, such as Escherichia coli bacteria, are expected to fill a volume homogeneously. However, we show that when a population of bacteria is exposed to a microfabricated wall of funnel-shaped openings, the random motion of bacteria through the openings is rectified by tracking (trapping) of the swimming bacteria along the funnel wall. This leads to a buildup of the concentration of swimming cells on the narrow opening side of the funnel wall but no concentration of nonswimming cells. Similarly, we show that a series of such funnel walls functions as a multistage pump and can increase the concentration of motile bacteria exponentially with the number of walls. The funnel wall can be arranged along arbitrary shapes and cause the bacteria to form well-defined patterns. The funnel effect may also have implications on the transport and distribution of motile microorganisms in irregular confined environments, such as porous media, wet soil, or biological tissue, or act as a selection pressure in evolution experiments. PMID:17890308

  9. Prediction of left ventricular remodeling in patients with acute myocardial infarction by speckle tracking imaging with wall motion score index:a clinical follow-up study%斑点追踪成像联合室壁运动评分预测急性心肌梗死患者左心室重构的随访研究

    Institute of Scientific and Technical Information of China (English)

    胡波; 周青; 陈金玲; 姚雪; 宋宏宁; 谭团团; 郭瑞强

    2016-01-01

    Objective To explore the prognostic value of speckle tracking imaging (STI) for left ventricular remodeling(LVR) in acute myocardial infarction (AMI) patients with the analysis of the relation between regional wall motion abnormality after AMI and LVR by STI in association with wall motion score index (WMSI).Methods Eighty-three patients with first onset AMI were enrolled from January 2012 to May 2015 and underwent echocardiography within 24 h of the onset and at 6-month follow-up.LVR was defined as more than 20% of the percentage change of left ventricular end-diastolic volume (△LVEDV%) from baseline to 6-month follow-up (divided as LVR and non-LVR group).Standard long-axis and shortaxis views were stored and analyzed for longitudinal (LS),radial (RS) and circumferential (CS) strain of STI metrics as well as scores of WMSI.Segments of WMSI≥2 were selected and calculated for the mean values of LS (LS_WMSI),RS (RS_WMSI) and CS (CS_WMSI).Results LVR occurred in twenty-seven AMI patients at 6-month follow-up.No difference has shown for demographics,electrocardiogram,lab tests,coronary angiography as well as the measurements of two-dimensional echocardiography between the two groups from baseline,while all STI metrics had statistical difference when the comparisons (P <0.05,all),especially the WMSI selected STI metrics (P <0.001,all).Linear regression analysis demonstrated that CS_WMSI (r =0.716,P <0.001) was best correlated to △LVEDV% among all STI metrics and also the best predictor of LVR by receive operator curve analysis (sensitivity of 92.6%,specificity of 87.5 % and area under the curve of 0.9563).Conclusions Baseline STI metrics can precisely predict LVR at 6-month follow-up.Among the STI metrics,CS_WMSI has shown preferable predictive and diagnostic value,which indicates that the impairment of segmental circumferential wall motion is closely correlated to LVR after myocardial infarction.%目的 应用斑点追踪成像(STI)技术联合

  10. Origin of stationary domain wall enhanced ferroelectric susceptibility

    Science.gov (United States)

    Liu, Shi; Cohen, R. E.

    2017-03-01

    Ferroelectrics usually adopt a multidomain state with domain walls separating domains with polarization axes oriented differently. It has long been recognized that domain walls can dramatically impact the properties of ferroelectric materials. The enhancement of low-field susceptibility/permittivity under subswitching conditions is usually attributed to reversible domain wall vibration. Recent experiments highlight the stationary domain wall contribution to the dielectric susceptibility irrespective of any lateral displacements or deformations of the wall. We study the effects of domain walls on the low-field permittivity of PbTiO3 with density functional theory and molecular dynamics simulations. The static dielectric constant is calculated as a function of increasing domain wall density and temperature. We find an increase of dielectric permittivity with increasing domain wall density, which is expected to occur at a low driving field where the lateral motion of domain walls is forbidden. Real-space decomposition of the dielectric response reveals that frustrated dipoles within the finite width of the domain walls are responsible for the enhanced low-field permittivity. We explain the 100 % enhancement of the dielectric susceptibility form domain walls, which arises from the softer potential wells within them.

  11. Near-wall diffusion tensor of an axisymmetric colloidal particle

    CERN Document Server

    Lisicki, Maciej; Wajnryb, Eligiusz

    2016-01-01

    Hydrodynamic interactions with confining boundaries often lead to drastic changes in the diffusive behaviour of microparticles in suspensions. For axially symmetric particles, earlier numerical studies have suggested a simple form of the near-wall diffusion matrix which depends on the distance and orientation of the particle with respect to the wall, which is usually calculated numerically. In this work, we derive explicit analytical formulae for the dominant correction to the bulk diffusion tensor of an axially symmetric colloidal particle due to the presence of a nearby no-slip wall. The relative correction scales as powers of inverse wall-particle distance and its angular structure is represented by simple polynomials in sines and cosines of the particle's inclination angle to the wall. We analyse the correction for translational and rotational motion, as well as the translation-rotation coupling. Our findings provide a simple approximation to the anisotropic diffusion tensor near a wall, which completes a...

  12. 利用定量组织速度成像技术评价心肌梗死患者局部心肌不同时相的纵向运动%Assessing longitudinal wall motion characteristics at different phases in regional myocardial in patients with myocardial infarction by quantitative tissue velocity imaging

    Institute of Scientific and Technical Information of China (English)

    张涓; 杨新春; 曾定尹; 吴雅峰

    2005-01-01

    BACKGROUND: At present, Doppler tissue imaging can be used extensively to make a quantitative assessment of left ventricular regional myocardial function. Postsystolic shortening is a delayed relaxation in regional myocardium following acute ischemia.OBJECTIVE: To observe longitudinal wall motion characteristics in left ventricular regional myocardiun and evaluate the clinical significance of postsystolic shortening in isovolumic relaxation period.DESIGN: Case-control observation.SETTING: Heart Center of Beijing Chaoyang Hospital.PARTICIPANTS: We selected 30 myocardial infarction inpatients hospitalized in the Heart Center of Beijing Chaoyang Hospital between April 2003 and September 2003 as myocardial infarction group; another 30 patients with non-cardiac diseases were set as control group. Subjects of the two groups volunteered in the experiment.METHODS: Dynamic images were collected and information was analyzed off-line. Left ventricular myocardial velocity and time velocity integral profiles were acquired along long axis asynchronously in basal and mid- segments of different walls. Peak velocity of isovolumic contraction period (VIC), ejection period (Ye), isovolumie relaxation period (VIR), rapid filling period (VRF) and atrial systole (VAS) and maximum time velocity integral (TVIMAX) in regional myocardium were measured.Doppler in different segments at longitudinal wall of myocardium in the the two groups.RESULTS: Thirty patients were recruited in myocardial infarction group and control group separately and all of them entered the result analysis ocardium was lower in myocardial infarction group than in control group,especially in infarcted segments, suggesting that the function of cardiac contraction and relaxation in patients with myocardial infarction was demyocardial isovolumic relaxation in myocardial infarction group, indicating period and isovolumic relaxation period in TVIMAX in myocardial infarction group.mal movement at isovolumic relaxation phase

  13. General anesthetic conditions induce network synchrony and disrupt sensory processing in the cortex

    Directory of Open Access Journals (Sweden)

    Thomas eLissek

    2016-04-01

    Full Text Available General anesthetics are commonly used in animal models to study how sensory signals are represented in the brain. Here, we used two-photon (2P calcium activity imaging with cellular resolution to investigate how neuronal activity in layer 2/3 of the mouse barrel cortex is modified under the influence of different concentrations of chemically distinct general anesthetics. Our results show that a high isoflurane dose induces synchrony in local neuronal networks and these cortical activity patterns closely resemble those observed in EEG recordings under deep anesthesia. Moreover, ketamine and urethane also induced similar activity patterns. While investigating the effects of deep isoflurane anesthesia on whisker and auditory evoked responses in the barrel cortex, we found that dedicated spatial regions for sensory signal processing become disrupted. We propose that our isoflurane-2P imaging paradigm can serve as an attractive model system to dissect cellular and molecular mechanisms that induce the anesthetic state, and it might also provide important insight into sleep-like brain states and consciousness.

  14. General Anesthetic Conditions Induce Network Synchrony and Disrupt Sensory Processing in the Cortex.

    Science.gov (United States)

    Lissek, Thomas; Obenhaus, Horst A; Ditzel, Désirée A W; Nagai, Takeharu; Miyawaki, Atsushi; Sprengel, Rolf; Hasan, Mazahir T

    2016-01-01

    General anesthetics are commonly used in animal models to study how sensory signals are represented in the brain. Here, we used two-photon (2P) calcium activity imaging with cellular resolution to investigate how neuronal activity in layer 2/3 of the mouse barrel cortex is modified under the influence of different concentrations of chemically distinct general anesthetics. Our results show that a high isoflurane dose induces synchrony in local neuronal networks and these cortical activity patterns closely resemble those observed in EEG recordings under deep anesthesia. Moreover, ketamine and urethane also induced similar activity patterns. While investigating the effects of deep isoflurane anesthesia on whisker and auditory evoked responses in the barrel cortex, we found that dedicated spatial regions for sensory signal processing become disrupted. We propose that our isoflurane-2P imaging paradigm can serve as an attractive model system to dissect cellular and molecular mechanisms that induce the anesthetic state, and it might also provide important insight into sleep-like brain states and consciousness.

  15. Did terrestrial diversification of amoebas (amoebozoa occur in synchrony with land plants?

    Directory of Open Access Journals (Sweden)

    Omar Fiz-Palacios

    Full Text Available Evolution of lineage diversification through time is an active area of research where much progress has been made in the last decade. Contrary to the situation in animals and plants little is known about how diversification rates have evolved in most major groups of protist. This is mainly due to uncertainty about phylogenetic relationships, scarcity of the protist fossil record and the unknown diversity within these lineages. We have analyzed the evolutionary history of the supergroup Amoebozoa over the last 1000 million years using molecular dating and species number estimates. After an origin in the marine environment we have dated the colonization of terrestrial habitats by three distinct lineages of Amoebozoa: Dictyostelia, Myxogastria and Arcellinida. The common ancestor of the two sister taxa, Dictyostelia and Myxogastria, appears to have existed before the colonization of land by plants. In contrast Arcellinida seems to have diversify in synchrony with land plant radiation, and more specifically with that of mosses. Detection of acceleration of diversification rates in Myxogastria and Arcellinida points to a co-evolution within the terrestrial habitats, where land plants and the amoebozoans may have interacted during the evolution of these new ecosystems.

  16. The anti-predator role of within-nest emergence synchrony in sea turtle hatchlings

    Science.gov (United States)

    Pinheiro, Hudson Tercio; Martins, Agnaldo Silva; Riul, Pablo; Bruno, Soraya Christina; Janzen, Fredric J.

    2016-01-01

    Group formation is a common behaviour among prey species. In egg-laying animals, despite the various factors that promote intra-clutch variation leading to asynchronous hatching and emergence from nests, synchronous hatching and emergence occurs in many taxa. This synchrony may be adaptive by reducing predation risk, but few data are available in any natural system, even for iconic examples of the anti-predator function of group formation. Here, we show for the first time that increased group size (number of hatchlings emerging together from a nest) reduces green turtle (Chelonia mydas) hatchling predation. This effect was only observed earlier in the night when predation pressure was greatest, indicated by the greatest predator abundance and a small proportion of predators preoccupied with consuming captured prey. Further analysis revealed that the effect of time of day was due to the number of hatchlings already killed in an evening; this, along with the apparent lack of other anti-predatory mechanisms for grouping, suggests that synchronous emergence from a nest appears to swamp predators, resulting in an attack abatement effect. Using a system with relatively pristine conditions for turtle hatchlings and their predators provides a more realistic environmental context within which intra-nest synchronous emergence has evolved. PMID:27383817

  17. Can hyper-synchrony in meditation lead to seizures? Similarities in meditative and epileptic brain states.

    Science.gov (United States)

    Lindsay, Shane

    2014-10-01

    Meditation is used worldwide by millions of people for relaxation and stress relief. Given sufficient practice, meditators may also experience a variety of altered states of consciousness. These states can lead to a variety of unusual experiences, including physical, emotional and psychic disturbances. This paper highlights the correspondences between brain states associated with these experiences and the symptoms and neurophysiology of epileptic simple partial seizures. Seizures, like meditation practice, can result in both positive and negative experiences. The neurophysiology and chemistry underlying simple partial seizures are characterised by a high degree of excitability and high levels of neuronal synchrony in gamma-band brain activity. Following a survey of the literature that shows that meditation practice is also linked to high power gamma activity, an account of how meditation could cause such activity is provided. This paper discusses the diagnostic challenges for the claim that meditation practices lead to brain states similar to those found in epileptic seizures, and seeks to develop our understanding of the range of pathological and non-pathological states that result from a hyper-excited and hyper-synchronous brain.

  18. Spatial synchrony of malaria outbreaks in a highland region of Ethiopia.

    Science.gov (United States)

    Wimberly, Michael C; Midekisa, Alemayehu; Semuniguse, Paulos; Teka, Hiwot; Henebry, Geoffrey M; Chuang, Ting-Wu; Senay, Gabriel B

    2012-10-01

    To understand the drivers and consequences of malaria in epidemic-prone regions, it is important to know whether epidemics emerge independently in different areas as a consequence of local contingencies, or whether they are synchronised across larger regions as a result of climatic fluctuations and other broad-scale drivers. To address this question, we collected historical malaria surveillance data for the Amhara region of Ethiopia and analysed them to assess the consistency of various indicators of malaria risk and determine the dominant spatial and temporal patterns of malaria within the region. We collected data from a total of 49 districts from 1999-2010. Data availability was better for more recent years and more data were available for clinically diagnosed outpatient malaria cases than confirmed malaria cases. Temporal patterns of outpatient malaria case counts were correlated with the proportion of outpatients diagnosed with malaria and confirmed malaria case counts. The proportion of outpatients diagnosed with malaria was spatially clustered, and these cluster locations were generally consistent from year to year. Outpatient malaria cases exhibited spatial synchrony at distances up to 300 km, supporting the hypothesis that regional climatic variability is an important driver of epidemics. Our results suggest that decomposing malaria risk into separate spatial and temporal components may be an effective strategy for modelling and forecasting malaria risk across large areas. They also emphasise both the value and limitations of working with historical surveillance datasets and highlight the importance of enhancing existing surveillance efforts. © 2012 Blackwell Publishing Ltd.

  19. Comparative study of reproductive synchrony at various scales in deep-sea echinoderms

    Science.gov (United States)

    Baillon, Sandrine; Hamel, Jean-François; Mercier, Annie

    2011-03-01

    This study examined the influence of temporal and spatial factors on the determination of reproductive cycles in selected deep-water echinoderms. The prevalence of inter-individual synchrony in the gametogenesis of three ubiquitous species, Phormosoma placenta (Echinoidea), Hippasteria phrygiana (Asteroidea) and Mesothuria lactea (Holothuroidea) collected off the coast of Newfoundland and Labrador (eastern Canada), was determined. Analyses revealed diverse degrees of gametogenic asynchrony at the scales examined (within trawls, between trawls over similar or different periods, as well as among depths and locations over the same period). Taken as a whole, samples did not show any annual or seasonal patterns, whereas some sets of samples, taken over a particular time period in the same area and at the same depth, revealed well synchronized maturing and/or spawning periods in P. placenta and H. phrygiana. This study presents evidence that determination of reproductive cycles in many deep-sea species may be affected by low sampling resolution inherent to most deep-sea studies. More accurate assessments of reproductive patterns and periodicities may require much tighter collection designs as several species are likely to rely on long-term or transient pairing and aggregation to synchronize their breeding activities.

  20. Coherence in consciousness: paralimbic gamma synchrony of self-reference links conscious experiences.

    Science.gov (United States)

    Lou, Hans C; Gross, Joachim; Biermann-Ruben, Katja; Kjaer, Troels W; Schnitzler, Alfons

    2010-02-01

    A coherent and meaningful percept of the world is essential for human nature. Consequently, much speculation has focused on how this is achieved in the brain. It is thought that all conscious experiences have reference to the self. Self-reference may either be minimal or extended, i.e., autonoetic. In minimal self-reference subjective experiences are self-aware in the weak sense that there is something it feels like for the subject to experience something. In autonoetic consciousness, consciousness emerges, by definition, by retrieval of memories of personally experienced events (episodic memory). It has been shown with transcranial magnetic stimulation (TMS) that a medial paralimbic circuitry is critical for self-reference. This circuitry includes anterior cingulate/medial prefrontal and posterior cingulate/medial parietal cortices, connected directly and via thalamus. We here hypothesized that interaction in the circuitry may bind conscious experiences with widely different degrees of self-reference through synchrony of high frequency oscillations as a common neural event. This hypothesis was confirmed with magneto-encephalography (MEG). The observed coupling between the neural events in conscious experience may explain the sense of unity of consciousness and the severe symptoms associated with paralimbic dysfunction.

  1. Traces across the body: influence of music-dance synchrony on the observation of dance.

    Science.gov (United States)

    Woolhouse, Matthew Harold; Lai, Rosemary

    2014-01-01

    In previous studies investigating entrainment and person perception, synchronized movements were found to enhance memory for incidental person attributes. Although this effect is robust, including in dance, the process by which it is actuated are less well understood. In this study, two hypotheses are investigated: that enhanced memory for person attributes is the result of (1) increased gaze time between in-tempo dancers; and/or (2) greater attentional focus between in-tempo dancers. To explore these possible mechanisms in the context of observing dance, an eye-tracking study was conducted in which subjects watched videos of pairs of laterally positioned dancers; only one of the dancers was synchronized with the music, the other being asynchronous. The results were consistent with the first hypothesis-music-dance synchrony gives rise to increased visual inspection times. In addition, there was a preference for upper-body fixations over lower-body fixations across both synchronous and asynchronous conditions. A subsequent, single-dancer eye-tracking study investigated fixations across different body regions, including head, torso, legs and feet. Significantly greater dwell times were recorded for head than torso and legs; feet attracted significantly less dwell time than any other body region. Lastly, the study sought to identify dance gestures responsible for torso- and head-directed fixations. Specifically we asked whether there are features in dance that are specially designed to direct an observer's gaze towards the face-the main "communicative portal" with respect to the transmission of intent, affect and empathy.

  2. The consistency of crossmodal synchrony perception across the visual, auditory, and tactile senses.

    Science.gov (United States)

    Machulla, Tonja-Katrin; Di Luca, Massimiliano; Ernst, Marc O

    2016-07-01

    Crossmodal judgments of relative timing commonly yield a nonzero point of subjective simultaneity (PSS). Here, we test whether subjective simultaneity is coherent across all pairwise combinations of the visual, auditory, and tactile modalities. To this end, we examine PSS estimates for transitivity: If Stimulus A has to be presented x ms before Stimulus B to result in subjective simultaneity, and B y ms before C, then A and C should appear simultaneous when A precedes C by z ms, where z = x + y. We obtained PSS estimates via 2 different timing judgment tasks-temporal order judgments (TOJs) and synchrony judgments (SJs)-thus allowing us to examine the relationship between TOJ and SJ. We find that (a) SJ estimates do not violate transitivity, and that (b) TOJ and SJ data are linearly related. Together, these findings suggest that both TOJ and SJ access the same perceptual representation of simultaneity and that this representation is globally coherent across the tested modalities. Furthermore, we find that (b) TOJ estimates are intransitive. This is consistent with the proposal that while the perceptual representation of simultaneity is coherent, relative timing judgments that access this representation can at times be incoherent with each other because of postperceptual response biases. (PsycINFO Database Record

  3. Synchrony and Divergence in Stream Metabolism across the Continental United States

    Science.gov (United States)

    Appling, A.; Read, J. S.; Hall, R. O., Jr.; Stets, E.; Stanley, E. H.; Bernhardt, E. S.; Heffernan, J. B.; Arroita, M.; Griffiths, N.; Harvey, J. W.; Lorenz, D. L.; Winslow, L.; Yackulic, C. B.

    2015-12-01

    River and stream ecosystems experience highly variable inputs of water, nutrients, organic matter, heat, and light over the scales of hours to storms to seasons. Despite the unstable physical and chemical environments of such ecosystems, benthic and pelagic communities persist and even thrive. Whole-stream metabolism estimates allow us to quantify the overall activity of these diverse and responsive communities. They also provide a holistic way to assess how the temporal patterns of that activity are structured by streams' dynamic hydrology and resource availability. We synthesized continental-scale datasets of high-frequency dissolved oxygen, discharge, water temperature, and light to estimate metabolism in over 200 streams to answer the question, "What are the drivers of synchrony and divergence in the temporal patterns of metabolism among streams of North America?" We find that short-term disturbances in the form of storms and cloudy days have strong proximate, dampening effects on whole-ecosystem metabolism; however, despite these strong proximate effects, streams with similar resource and discharge regimes are largely synchronous in their overall seasonal patterns. The median date of peak gross primary productivity is close to the summer solstice in June, while ecosystem respiration has two most-common annual peaks, one in early spring and another in mid fall. These differences in peak timing point to systematic differences at the continental scale in the timing of light versus organic matter availability, with consequent seasonality in net ecosystem productivity.

  4. The effects of visual material and temporal synchrony on the processing of letters and speech sounds.

    Science.gov (United States)

    Mittag, Maria; Takegata, Rika; Kujala, Teija

    2011-06-01

    Associating letters with speech sounds is essential for reading skill acquisition. In the current study, we aimed at determining the effects of different types of visual material and temporal synchrony on the integration of letters and speech sounds. To this end, we recorded the mismatch negativity (MMN), an index of automatic change detection in the brain, from literate adults. Subjects were presented with auditory consonant-vowel syllable stimuli together with visual stimuli, which were either written syllables or scrambled pictures of the written syllables. The visual stimuli were presented in half of the blocks synchronously with the auditory stimuli and in the other half 200 ms before the auditory stimuli. The auditory stimuli were consonant, vowel or vowel length changes, or changes in syllable frequency or intensity presented by using the multi-feature paradigm. Changes in the auditory stimuli elicited MMNs in all conditions. MMN amplitudes for the consonant and frequency changes were generally larger for the sounds presented with written syllables than with scrambled syllables. Time delay diminished the MMN amplitude for all deviants. The results suggest that speech sound processing is modulated when the sounds are presented with letters versus non-linguistic visual stimuli, and further, that the integration of letters and speech sounds seems to be dependent on precise temporal alignment. Moreover, the results indicate that with our paradigm, a variety of parameters relevant and irrelevant for reading can be tested within one experiment.

  5. Synchrony between fruit maturation and effective dispersers' foraging activity increases seed protection against seed predators.

    Science.gov (United States)

    Boulay, Raphaël; Carro, Francisco; Soriguer, Ramón C; Cerdá, Xim

    2007-10-22

    The evolution of pollination and seed dispersal mutualisms is conditioned by the spatial and temporal co-occurrence of animals and plants. In the present study we explore the timing of seed release of a myrmecochorous plant (Helleborus foetidus) and ant activity in two populations in southern Spain during 2 consecutive years. The results indicate that fruit dehiscence and seed shedding occur mostly in the morning and correspond to the period of maximum foraging activity of the most effective ant dispersers. By contrast, ant species that do not transport seeds and/or that do not abound near the plants are active either before or after H. foetidus diaspores are released. Experimental analysis of diet preference for three kinds of food shows that effective ant dispersers are mostly scavengers that readily feed on insect corpses and sugars. Artificial seed depots suggest that seeds deposited on the ground out of the natural daily time window of diaspore releasing are not removed by ants and suffer strong predation by nocturnal rodents Apodemus sylvaticus. Nevertheless, important inter-annual variations in rodent populations cast doubts on their real importance as selection agents. We argue that traits allowing synchrony between seed presentation and effective partners may constitute a crucial pre-adaptation for the evolution of plant-animal mutualisms involving numerous animal partners.

  6. Electroencephalographic frontal synchrony and caudal asynchrony during painful hand immersion in cold water.

    Science.gov (United States)

    Levitt, Joshua; Choo, Hyunwoo J; Smith, Kelsey A; LeBlanc, Brian W; Saab, Carl Y

    2017-04-01

    Recent studies in our laboratory showed that cortical theta oscillations correlate with pain in rodent models. In this study, we sought to validate our pre-clinical data using EEG recordings in humans during immersion of the hand in ice cold water, a moderately noxious stimulus. Power spectral analysis shows that an increase in pain score is associated with an increase in power amplitude within a frequency range of 6-7Hz at the frontal (Fz) electrode. These results are consistent with our previous pre-clinical animal studies and the clinical literature. We also report a novel reduction in power at the caudal (O1) electrode within a broader 3-30Hz rand and decreased coherence between Fz and C3, C4 electrodes within the theta (4-8Hz) and low beta (13-21Hz) bands, while coherence (an indirect measure of functional connectivity) between Fz and O1 increased within the theta and alpha (8-12Hz) bands. We argue that pain is associated with EEG frontal synchrony and caudal asynchrony, leading to the disruption of cortico-cortical connectivity. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Dizziness and Motion Sickness

    Science.gov (United States)

    ... ENTCareers Marketplace Find an ENT Doctor Near You Dizziness and Motion Sickness Dizziness and Motion Sickness Patient ... vision or speech, or hearing loss. What is dizziness? Dizziness can be described in many ways, such ...

  8. Abdominal wall fat pad biopsy

    Science.gov (United States)

    Amyloidosis - abdominal wall fat pad biopsy; Abdominal wall biopsy; Biopsy - abdominal wall fat pad ... method of taking an abdominal wall fat pad biopsy . The health care provider cleans the skin on ...

  9. A model-based time-reversal of left ventricular motion improves cardiac motion analysis using tagged MRI data

    Directory of Open Access Journals (Sweden)

    Cook Larry T

    2008-05-01

    Full Text Available Abstract Background Myocardial motion is an important observable for the assessment of heart condition. Accurate estimates of ventricular (LV wall motion are required for quantifying myocardial deformation and assessing local tissue function and viability. Harmonic Phase (HARP analysis was developed for measuring regional LV motion using tagged magnetic resonance imaging (tMRI data. With current computer-aided postprocessing tools including HARP analysis, large motions experienced by myocardial tissue are, however, often intractable to measure. This paper addresses this issue and provides a solution to make such measurements possible. Methods To improve the estimation performance of large cardiac motions while analyzing tMRI data sets, we propose a two-step solution. The first step involves constructing a model to describe average systolic motion of the LV wall within a subject group. The second step involves time-reversal of the model applied as a spatial coordinate transformation to digitally relax the contracted LV wall in the experimental data of a single subject to the beginning of systole. Cardiac tMRI scans were performed on four healthy rats and used for developing the forward LV model. Algorithms were implemented for preprocessing the tMRI data, optimizing the model parameters and performing the HARP analysis. Slices from the midventricular level were then analyzed for all systolic phases. Results The time-reversal operation derived from the LV model accounted for the bulk portion of the myocardial motion, which was the average motion experienced within the overall subject population. In analyzing the individual tMRI data sets, removing this average with the time-reversal operation left small magnitude residual motion unique to the case. This remaining residual portion of the motion was estimated robustly using the HARP analysis. Conclusion Utilizing a combination of the forward LV model and its time reversal improves the performance of

  10. Objects in Motion

    Science.gov (United States)

    Damonte, Kathleen

    2004-01-01

    One thing scientists study is how objects move. A famous scientist named Sir Isaac Newton (1642-1727) spent a lot of time observing objects in motion and came up with three laws that describe how things move. This explanation only deals with the first of his three laws of motion. Newton's First Law of Motion says that moving objects will continue…

  11. Liquid Wall Chambers

    Energy Technology Data Exchange (ETDEWEB)

    Meier, W R

    2011-02-24

    The key feature of liquid wall chambers is the use of a renewable liquid layer to protect chamber structures from target emissions. Two primary options have been proposed and studied: wetted wall chambers and thick liquid wall (TLW) chambers. With wetted wall designs, a thin layer of liquid shields the structural first wall from short ranged target emissions (x-rays, ions and debris) but not neutrons. Various schemes have been proposed to establish and renew the liquid layer between shots including flow-guiding porous fabrics (e.g., Osiris, HIBALL), porous rigid structures (Prometheus) and thin film flows (KOYO). The thin liquid layer can be the tritium breeding material (e.g., flibe, PbLi, or Li) or another liquid metal such as Pb. TLWs use liquid jets injected by stationary or oscillating nozzles to form a neutronically thick layer (typically with an effective thickness of {approx}50 cm) of liquid between the target and first structural wall. In addition to absorbing short ranged emissions, the thick liquid layer degrades the neutron flux and energy reaching the first wall, typically by {approx}10 x x, so that steel walls can survive for the life of the plant ({approx}30-60 yrs). The thick liquid serves as the primary coolant and tritium breeding material (most recent designs use flibe, but the earliest concepts used Li). In essence, the TLW places the fusion blanket inside the first wall instead of behind the first wall.

  12. Analysis of particle-wall interactions during particle free fall.

    Science.gov (United States)

    Chein, Reiyu; Liao, Wenyuan

    2005-08-01

    In this study, the vertical motion of a particle in a quiescent fluid falling toward a horizontal plane wall is analyzed, based on simplified models. Using the distance between the particle and wall as a parameter, the effects of various forces acting on the particle and the particle motion are examined. Without the colloidal and Brownian forces being included, the velocity of small particles is found to be approximately equal to the inverse of the drag force correction function used in this study as the particle approaches the near-wall region. Colloidal force is added to the particle equation of motion as the particle moves a distance comparable to its size. It is found that the particle might become suspended above or deposited onto the wall, depending on the Hamaker constant, the surface potentials of the particle and wall, and the thickness of the electrical double layer (EDL). For strong EDL repulsive force and weaker van der Waals (VDW) attractive force, the particle will become suspended above the wall at a distance at which the particle velocity is zero. This location is referred to as the equilibrium distance. The equilibrium distance is found to increase with increased in EDL thickness when a repulsive force barrier appears in the colloidal force interaction. For the weak EDL repulsive force and strong VDW attractive force case, the particle can become deposited onto the wall without the Brownian motion effect. The Brownian jump length was found to be very small. Many Brownian jumps would be required in a direction toward the wall for a suspended particle to become deposited.

  13. Smoothing Motion Estimates for Radar Motion Compensation.

    Energy Technology Data Exchange (ETDEWEB)

    Doerry, Armin W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-07-01

    Simple motion models for complex motion environments are often not adequate for keeping radar data coherent. Eve n perfect motion samples appli ed to imperfect models may lead to interim calculations e xhibiting errors that lead to degraded processing results. Herein we discuss a specific i ssue involving calculating motion for groups of pulses, with measurements only available at pulse-group boundaries. - 4 - Acknowledgements This report was funded by General A tomics Aeronautical Systems, Inc. (GA-ASI) Mission Systems under Cooperative Re search and Development Agre ement (CRADA) SC08/01749 between Sandia National Laboratories and GA-ASI. General Atomics Aeronautical Systems, Inc. (GA-ASI), an affilia te of privately-held General Atomics, is a leading manufacturer of Remotely Piloted Aircraft (RPA) systems, radars, and electro-optic and rel ated mission systems, includin g the Predator(r)/Gray Eagle(r)-series and Lynx(r) Multi-mode Radar.

  14. Rolling Shutter Motion Deblurring

    KAUST Repository

    Su, Shuochen

    2015-06-07

    Although motion blur and rolling shutter deformations are closely coupled artifacts in images taken with CMOS image sensors, the two phenomena have so far mostly been treated separately, with deblurring algorithms being unable to handle rolling shutter wobble, and rolling shutter algorithms being incapable of dealing with motion blur. We propose an approach that delivers sharp and undis torted output given a single rolling shutter motion blurred image. The key to achieving this is a global modeling of the camera motion trajectory, which enables each scanline of the image to be deblurred with the corresponding motion segment. We show the results of the proposed framework through experiments on synthetic and real data.

  15. Solar heating wall

    Energy Technology Data Exchange (ETDEWEB)

    Schoenfelder, J.L.

    1983-08-16

    A solar heating wall is disclosed including a water pipe circulation system having a plurality of separate tubes, each formed as a loop, connected between a water supply and a return. The separate tubes are arranged in a single vertical plane at the approximate center of the wall. The wall is formed within a frame which is packed with a material suited for use as a thERMAL RESERVOIR, SUCH AS concrete. The frame provides extra support by having a series of horizontally disposed cross supports on one surface of the wall and a series of vertically disposed cross supports on the opposite surface A pressure relief valve may be provided between the water supply to the separate tubes and the water supply to the building or structure containing the solar wall, so that the solar wall can be adapted for use with a city water system.

  16. Structural