Relative Phase

We investigate the group velocity of the probe light pulse in an open V-type system with spontaneously generated coherence. We find that, not only varying the relative phase between the probe and driving pulses can but varying the atomic exit rate or incoherent pumping rate also can manipulate dramatically the group velocity, even make the pulse propagation switching from subluminal to superluminal; the subliminal propagation can be companied with gain or absorption, but the superluminal propagation is always companied with absorption.

The behaviour of the Ã-system has been studied theoretically in the context of atom localization. In addition to the probe field and the standing wave driving field, a microwave field is introduced to couple the two lower states, and as a result our Ã-system forms a closed loop. Therefore phase-sensitive atom localization is expected. Indeed by appropriate choice of the relative phase between three fields, an improvement by a factor of 2 has been found in the detection probability of atoms within the sub-wavelength domain of the standing wave. The effect of other parameters is also investigated.

Todo proceso hacia el logro de una habilidad motora comporta un aprendizaje, un control y una coordinación motora. La coordinación motora es generalmente definida como las relaciones espacio-temporales que existen entre diferentes segmentos corporales. El objetivo de este artículo fue dar a conocer una metodología para el estudio de la coordinación motora. Los ángulos de fase y la fase relativa continua son dos técnicas que posibilitan conocer la relación desplazamiento/velocidad angular de uno o varios segmentos durante todo el movimiento. Dichas técnicas generan unos gráficos cuyas trayectorias nos indicaron cómo los diferentes segmentos se coordinaban (en fase o fuera de fase). Con ello, pudimos conocer las estrategias coordinativas a las que los individuos recurrían al realizar una tarea nueva. A pesar de los resultados obtenidos, los ángulos de fase y la fase relativa continua no representaron el movimiento en su totalidad y se fundamentan en un análisis cualitativo. Por lo tanto, recomendamos al investigador tener en cuenta: (1) complementar el análisis con variables cuantitativas que reflejen la dinámica de los diferentes segmentos; y (2) seleccionar la normalización en función de las variables a analizar.

Relative phase was recently suggested as a key variable for the dynamical modeling of coordination in both quadruped locomotion and undulation swimming in ®sh. Relative phase analysis has not yet been applied, however, to the behavior of intact, freely moving animals, but only to simpli®ed situations involving restrained animals and humans. In order to investigate relative phase under free movement conditions, we ®lmed free locomotion of ferrets (Mustella putorius) from below (through a glass ¯oor) and measured the lateral bending along the head, torso, and tail, and the location of the four paws. We introduced an algorithm which extracts the phase (and thus also the relative phase) even when the movements were neither periodic nor symmetric. Our results show that relative phases between segments have preferred values, which are relatively independent of the amplitude, duration, and asymmetry of the movement. In particular, both walking and turning can be explained as modulations of a single pattern: a cephalo-caudal, traveling wave of lateral movement with a wavelength of approximately one length of the body. The relative phase between movements of adjacent segments is similar when the body is in S shape (i.e., when walking forward), or C shape (i.e., when turning). The movements of the paws in the horizontal plane can also be considered as part of this traveling wave. Our ®ndings suggest that the concept of traveling waves of lateral bending, as found in the locomotion of undulating ®sh, can be generalized in two ways: (i) by considering the axis around which the movement is centered, it applies not only to forward locomotion, but also to turning; (ii) by incorporating the position of the paws, it applies also to the movement of quadrupeds. Our ®ndings suggest that the relative phase, once it is generalized to asymmetric and quasi-periodic movement, is suitable for modeling coordination patterns under free movement conditions.

This study aims to test the hypothesis that handwriting is governed by the dynamics of non-linear coupled oscillators. Accordingly, its first goal is to identify preferred, basic graphic shapes corresponding to spontaneously stable combinations of the two frequency-locked oscillatory x-y components of the trajectories. Six participants were required to produce 26 ellipsoids of varying eccentricities and orientations presented consecutively on a graphic tablet. These shapes corresponded to a systematic manipulation of the relative phase and the relative amplitude of the oscillators by a constant step. Results showed that among those, only eight ellipsoids were produced in a spontaneous and stable fashion. They were characterized by attraction of nearby shapes, and by a higher accuracy and velocity. Alike all periodic motion, graphic skills, hence handwriting, exhibit preferred coordination patterns, which can be ascribed to the non-linear coupling of two oscillators.

This study aimed to examine young swimmers' behavioral flexibility when facing different task constraints, such as swimming speed and stroke frequency. Eighteen (five boys and 13 girls) 13-to 15-year-old swimmers performed a 15 × 50-m front crawl with five trials, at 100%, 90%, and 70% each of their 50 m maximal swimming speed and randomly at 90%, 95%, 100%, 105%, and 110% of their preferred stroke frequency. Seven aerial and six underwater cameras were used to assess kinematics (one cycle), with upper-limb coordination computed through a continuous relative phase and index of coordination. A cluster analysis identified six patterns of coordination used by swimmers when facing various speed and stroke frequency constraints. The patterns' nature and the way the swimmers shifted between them are more important than getting the highest number of patterns (range of repertoire), that is, a change in the motor pattern in order to adapt correctly is more important than being able to execute a great number of patterns.

Using data from the E791 fixed-target hadroproduction experiment at Fermilab we have studied the Cabibbo-favored but phase-space suppressed decay, D 0 → K − K − K + π +. We find the decay rate for this mode to be (0.54 ± 0.16 ± 0.08) × 10 −2 times that for the normalization mode D 0 → K − π − π + π +. We observe a clear signal for D 0 → φK − π + which is consistent with producing 0.7 ± 0.3 of the D 0 → K − K − K + π + signal. In the context of simple models, we use our measurements to estimate the importance of decay amplitudes that produce extra quark-antiquark pairs from the vacuum relative to those that do not.

In rowing, perfect synchronisation is important for optimal performance of a crew. Remarkably, a recent study on ergometers demonstrated that antiphase crew coordination might be mechanically more efficient by reducing the power lost to within-cycle velocity fluctuations of the boat. However, coupled oscillator dynamics predict the stability of the coordination to decrease with increasing stroke rate, which in case of antiphase may eventually yield breakdowns to in-phase. Therefore, this study examined the effects of increasing stroke rate on in-and antiphase crew coordination in rowing dyads. Eleven experienced dyads rowed on two mechanically coupled ergometers on slides, which allowed the ergometer system to move back and forth as one 'boat'. The dyads performed a ramp trial in both inand antiphase pattern, in which stroke rates gradually increased from 30 strokes per minute (spm) to as fast as possible in steps of 2 spm. Kinematics of rowers, handles and ergometers were captured. Two dyads showed a breakdown of antiphase into in-phase coordination at the first stroke rate of the ramp trial. The other nine dyads reached between 34-42 spm in antiphase but achieved higher rates in in-phase. As expected, the coordinative accuracy in antiphase was worse than in in-phase crew coordination, while, somewhat surprisingly, the coordinative variability did not differ between the patterns. Whereas crew coordination did not substantially deteriorate with increasing stroke rate, stroke rate did affect the velocity fluctuations of the ergometers: fluctuations were clearly larger in the inphase pattern than in the antiphase pattern, and this difference significantly increased with stroke rate. Together, these results suggest that although antiphase rowing is less stable (i.e., less resistant to perturbation), potential on-water benefits of antiphase over in-phase rowing may actually increase with stroke rate.

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Chronic low back pain patients have been observed to show a reduced shift of thorax-pelvis relative phase towards out-of-phase movement with increasing speed compared to healthy controls. Here, we review the literature on this phase shift in patients with low back pain and we analyze the results presented in literature in view of the theoretical motivations to assess this phenomenon. Initially, based on the dynamical systems approach to movement coordination, the shift in thorax-pelvis relative phase with speed was studied as a self-organizing transition. However, the phase shift is gradual, which does not match a self-organizing transition. Subsequent emphasis in the literature therefore shifted to a motivation based on biomechanics. The change in relative phase with low back pain was specifically linked to expected changes in trunk stiffness due to 'guarded behavior'. We found that thorax-pelvis relative phase is affected by several interacting factors, including active drive of thorax rotation through trunk muscle activity, stride frequency and the magnitude of pelvis rotations. Large pelvis rotations and high stride frequency observed in low back pain patients may contribute to the difference between patients and controls. This makes thorax-pelvis relative phase a poor proxy of trunk stiffness. In conclusion, thorax-pelvis relative phase cannot be considered as a collective variable reflecting the orderly behaviour of a complex underlying system, nor is it a marker of specific changes in trunk biomechanics. The fact that it is affected by multiple factors may explain the considerable between-subject variance of this measure in low back pain patients and healthy controls alike.

We investigate the effect of quantum interference in the phase-dependent spectra of a V-type three-level atom where both transitions from the upper states to the lower state are driven by a single coherent field. In addition, the atom is damped by a broadband squeezed field. We are particularly interested in the role of the vacuum induced coherence on the spectrum of quantum fluctuations in phase quadratures of resonance fluorescence. We find that in some circumstances, the combined effect of the squeezed field and the vacuum induced coherence (VIC) can significantly modify the nonclassical behavior of the system. In particular, it is possible to enhance the squeezing in marked contrast with the case where the atom is damped by the standard vacuum. The squeezing spectrum can be modified by changing the relative phase of the squeezed vacuum to the external coherent field.

A change in cadence during walking or running might be indicated for a variety of reasons, among which mobility improvement and injury prevention. In a within-subject study design, we examined whether walking or running cadences are modulated best by means of step-based or stride-based auditory pacing. Sixteen experienced runners walked and ran on a treadmill while synchronizing with step-based and stride-based pacing at slow, preferred and fast pacing frequencies in synchronization-perturbation and synchronization-continuation conditions. We quantified the variability of the relative phase between pacing cues and footfalls and the responses to perturbations in the pacing signal as measures of coordinative stability; the more stable the auditory-motor coordination, the stronger the modulating effect of pacing. Furthermore, we quantified the deviation from the prescribed cadence after removal of the pacing signal as a measure of internalization of this cadence. Synchronization was achieved less often in running, especially at slow pacing frequencies. If synchronization was achieved, coordinative stability was similar, and the paced cadence was well internalized for preferred and fast pacing frequencies. Step-based pacing led to more stable auditory-motor coordination than stride-based pacing in both walking and running. We therefore concluded that step-based auditory pacing deserves preference as a means to modulate cadence in walking and running.

We study the quantum Fisher information (QFI) of a system of several particles which is in a superposition of a GHZ and two W states with arbitrary relative phase. We show that as the number of particles increases from 3 to 4, the behavior of QFI drastically changes. We also show how the dependence of QFI on the relative phase weakens as the number of particles increases. We also analyze the QFI for the state for several instances of N due to the change of the relative phases.

The regeneration phase of K S relahve to K L has been redetermmed using new data for the total K + and Kcross sectwns. We now find cos qbf = 1.06 + 0.09. If this result is combined with measurements of the interference between regenerated K S and K L in the ~7+~ -decay, the phase of the CP wolatmg amphtude 7/+_ is ~P?7 +_ = (1.47~-0.30) sign Am.

We exploit the quantum coherence between pair-produced D 0 andD 0 in ψ(3770) decays to make a first determination of the relative strong phase differences between D 0 → K 0 S π + π − andD 0 → K 0 S π + π − , which are of great importance in determining the CKM angle γ/φ 3 in B − → D 0 (D 0)K − decays. Using 818 pb −1 of e + e − collision data collected with the CLEO-c detector at E cm = 3.77 GeV, we employ a binned Dalitz-plot analysis of K 0 S π + π − and K 0 L π + π − decays recoiling against flavor-tagged, CP-tagged and K 0 S π + π − tagged events to determine these strong phase differences.

Bimanual in-phase and anti-phase coordination modes represent two basic movement patterns with distinct characteristics-homologous muscle contraction and non-homologous muscle contraction, respectively. A method to understand the contribution of each limb to the overall coordination pattern involves detuning (Δω) the natural eigenfrequency of each limb. In the present experiment, we experimentally broke the symmetry between the two upper limbs by adding elastic and viscous force fields using a Kinarm robot exoskeleton. We measured the effect of this symmetry breaking on coordination stability as participants performed bimanual in-phase and anti-phase movements using their left and right hand in 1:1 frequency locking mode. Differences between uncoupled frequencies were manipulated via the application of viscous & elastic force fields and using fast and slow oscillation frequencies with a custom task developed using the Kinarm robotic exoskeleton. The effects of manipulating the asymmetry between the limbs were measured through the mean and variability of relative phase (ϕ) from the intended modes of 0 ° or 180 °. In general, participants deviated less from intended phase irrespective of coordination mode in all matched conditions, except for when elastic loads are applied to both arms in the anti-phase coordination. Second, we found that when force fields were mismatched participants exhibited a larger deviation from the intended phase. Overall, there was increased phase deviation during anti-phase coordination. Finally, participants exhibited higher variability in relative phase in mismatched force conditions compared to matched force conditions, with overall higher variability during anti-phase coordination mode. We extend previous research by demonstrating that symmetry breaking caused by force differences between the limbs disrupts stability in each coordination mode.

Bimanual in-phase and anti-phase coordination modes represent two basic movement patterns with distinct characteristics—homologous muscle contraction and non-homologous muscle contraction, respectively. A method to understand the contribution of each limb to the overall coordination pattern involves detuning (Δω) the natural eigenfrequency of each limb. In the present experiment, we experimentally broke the symmetry between the two upper limbs by adding elastic and viscous force fields using a Kinarm robot exoskeleton. We measured the effect of this symmetry breaking on coordination stability as participants performed bimanual in-phase and anti-phase movements using their left and right hand in 1:1 frequency locking mode. Differences between uncoupled frequencies were manipulated via the application of viscous & elastic force fields and using fast and slow oscillation frequencies with a custom task developed using the Kinarm robotic exoskeleton. The effects of manipulating the asymm...

In earlier work [1] a dynamic theory of behavioral and neural patterns was developed, that was based on collective variables (or order parameters) and their (intrinsic) dynamics. Observed patterns were mapped onto attractors of the stochastic order parameter dynamics, with stability, fluctuations and time scales as central concepts. The influences of environmental information and of learned behavioral patterns were understood as additional contributions to the order parameter dynamics, leading to modifications of the stable behavioral patterns [2]. Here we ask how the processes of learning a behavioral pattern and activation of a learned pattern (variously termed recall or recognition) can be understood within our approach.

In our recent reports motor coordination of human lower limbs has been investigated during pedaling a special kind of ergometer which allows its left and right pedals to rotate independently. In particular, relative phase between left and right rotational-velocity waveforms of the pedals and their amplitude modulation have been analyzed for patients with Parkinson's disease (PD). Several patients showed peculiar interlimb coordination different from the regular anti-phase pattern of normal subjects. We have reported that these disordered patterns could be classified into four groups. Moreover, it has been demonstrated that a mathematical model could reproduce most of the disordered patterns. Such a model includes a schematization of the central pattern generator with two identical half-centers mutually coupled and two tonic control signals from higher motor centers, each of which inputs to one of the half-centers. Depending on the intensities of the tonic signals and on the differences between them, the model could generate a range of dynamics comparable to the clinically observed disordered patterns. In this paper, we explore the dynamics of the model by varying the intensities of the tonic signals in the model. Using the same method used for classifying the clinical data, the dynamics of the model are classified into several groups. The classified groups for the simulated data are compared with those for the clinical data to look at qualitative correspondence. Our systematic exploration of the model's dynamics in a wide range of the parameter space has revealed global organization of the bifurcations including Hopf bifurcations and cascades of period-doubling bifurcations among others, suggesting that the bifurcations, induced by instability of stable dynamics of the human motor control system, are responsible for the emergence of the disordered coordination in PD patients.

The accuracy of an atomic clock depends in part on the bandwidth of the relevant atomic transitions. Here we consider an ensemble of atoms whose transition frequencies have been independently perturbed by environmental effects or other factors. We consider the possibility of using the quantum Zeno effect to lock the relative phase of the atoms, which would decrease their effective bandwidth by a factor of \(1/\sqrt N .\) We analyze an example in which the quantum Zeno effect can be used to lock the relative phase of a pair of atoms, after which the elapsed time can be determined. Practical applications may require \(N>>1\) in order to achieve a good signal-to-noise ratio.

As one of the hallmarks of human activity and cultural achievement, bimanual coordination has been the focus of research efforts in multiple fields of inquiry. Since the seminal work of Cohen (1971) and Kelso and colleagues (Haken, Kelso, & Bunz, 1985; Kelso, Southard, & Goodman, 1979), bimanual action has served as a model system used to investigate the role of cortical, perceptual, cognitive, and situational underpinnings of coordinated movement sequences (e.g., Bingham, 2004; Oliveira & Ivry, 2008). This work has been guided primarily by dynamical systems theory in general, and by the formal Haken–Kelso–Bunz (HKB; 1985) model of bimanual coordination, in particular. The HKB model describes the self‐organizing relationship between a coordinated movement pattern and the underlying parameters that support that pattern, and can also be used to conceptualize and test predictions of how changes in coordination occur.Much of the work investigating bimanual control under the HKB model ha...

Visual information plays an adaptive role in the relation between bimanual force coupling and error corrective processes of isometric force control. In the present study, the evolving distribution of the relative phase properties of bimanual isometric force coupling was examined by scaling within a trial the temporal feedback rate of visual intermittency (short to long presentation intervals and vice versa). The force error (RMSE) was reduced, and time-dependent irregularity (SampEn) of the force output was increased with greater amounts of visual information (shorter intermittency). Multi-stable coordination patterns of bimanual isometric force control were differentially shifted toward and away from the intrinsic dynamics by the changing the intermittency of visual information. The distribution of Hilbert transformed relative phase values showed progressively a predominantly anti-phase mode under less intermittent visual information to predominantly an in-phase mode with limited (...

Paper presents the quantified assessment of stroke-affected upper extremity (UE) coordination via continuous relative phase (CRP) analysis. 14 post-stroke patients were divided into 3 groups based on the severity of impairment according to Wolf Motor Function Test (WMFT). CRP was determined based on UE kinematics parameters measured using inertial measurement units fixed on arm, forearm and hand while subjects performed designated movement. UE movement cycles were analysed based on the metrics derived from phase planes, the phase angle and CRP plots, as well as the calculated range of motions and CRP variability rates. It was found that CRP variability is associated with impairment level, i.e. it is decreasing with a higher level of dysfunction. Therefore, the CRP might serve as measurable quantity and could be valuable for supporting clinical assessment and quantifying impairment severity of UE motor functions.

We study the propagation of two weak light pulses with the same temporal shape, symmetrically detuned from a stronger cw pump, in a two-level system which decays via a shelving state. We show that the group velocity of the weak pulses can be controlled, with small distortion, by modifying either the relative amplitude of the weak pulses or the total phase Φ. The changes in the local group velocity on propagation are due to pump absorption, and to changes in the total phase on propagation which occur for all cases apart from the case where the amplitudes of the weak fields are equal and Φ = 0 or π. Slow light occurs when the initial total phase Φ = 0; π = 2 but not when Φ = π; when one pulse is less intense than the other, it experiences the greater slowing down, and the effect is greater than in the case of equal intensities.

We study the dynamical effects induced by a squeezed vacuum field interacting with the atoms of a standard single mode optical bistable system. We show that by varying the relative phase between the squeezed vacuum field and the coherent input light one can force the system to switch from a low to a high transmission state and vice versa. This effect is caused by the variation of the atomic relaxation rates induced by the squeezed vacuum.

In this paper, we are presenting an alternative approach to the investigation of lower extremity coupling referred to as a dynamical systems approach. In this approach, we calculate the phase angle of each segment and joint angle. Pairing the key segment/ joint motions, we use phase angles to determine the continuous relative phase and the variability of the continuous relative phase. Data from two studies illustrate the ecacy of the dynamical systems approach. Individuals who were asymptomatic, even though they may have anatomical aberrant structural problems (i.e. high Q-angle vs low Q-angle) showed no dierences in the pattern of the continuous relative phase or in the variability of the continuous phase. However, dierences in the variability of the continuous relative phase were apparent in comparing individuals who were symptomatic with patellofemoral pain with non-injured individuals. Patellofemoral pain individuals showed less variability in the continuous relative phase of the lower extremity couplings than did the healthy subjects. We hypothesize that the lower variability of the couplings in the symptomatic individuals indicates repeatable joint actions within a very narrow range. Relevance We claim that the traditional view of the variability of disordered movement is not tenable and suggest that there is a functional role for variability in lower extremity segment coupling during locomotion. While the methods described in this paper cannot determine a cause of the injury, they may be useful in the detection and treatment of running injuries.

early work will be used as the standard definition. Sherrington defined proprioception as the culmination of all neural inputs originating from joints, tendons, muscles, and associated deep tissue proprioceptors. These inputs are projected to the central nervous system for processing and ultimately result in the regulation of reflexes and motor control. This definition views proprioception primarily as a sensory activity, occurring along the afferent pathway. More recently, the definition of the proprioceptive system has been expanded to include the complex interaction between the sensory pathways and the motor pathway (efferent system). This system has come to be known as the sensorimotor system. 33 Neurophysiology of Proprioception and Neuromuscular Control of the Joint When a proprioceptive stimulus is presented to the body, input occurs at three separate locations, including the visual system, the vestibular system, and the peripheral mechanoreceptors (Fig 1). These peripheral mechanoreceptors are Fig 1. A flow chart of lower limb dynamic neuromuscular response to sensory receptor input is shown.

Superheterodyned NMR spectrometers which are useful over a wide frequency range and have four rf pulses with phases differing by 90" and quadrature detection require a number of circuits which split an incoming signal into two outputs differing in phase by 90 or 180". Such a circuit which is very inexpensive to construct is described. This particular circuit allows the relative phases of the two outputs to be adjusted to within 0.1" and the long-term stability is such that the relative phase does not vary by more than 0.5". The amplitudes of the output signals can also be adjusted separately.

We detail a method for the preparation of atomic coherence in a high density atomic medium, utilising a coherent preparation scheme of gigahertz bandwidth pulses. A numerical simulation of the preparation scheme is developed, and its efficiency in preparing coherent states is found to be close to unity at the entrance to the medium. The coherence is then measured non-invasively with a probe field.

College of the Holy Cross Perception of relative phase and phase variability may play a fundamental role in interlimb coordination. This study was designed to investigate the perception of relative phase and of phase variability and the stability of perception in each case. Observers judged the relative phasing of two circles rhythmically moving on a computer display. The circles moved from side to side, simulating movement in the frontoparallel plane, or increased and decreased in size, simulating movement in depth. Under each viewing condition, participants observed the same displays but were to judge either mean relative phase or phase variability. Phase variability interfered with the mean-relative-phase judgments, in particular when the mean relative phase was 0°. Judgments of phase variability varied as a function of mean relative phase. Furthermore, the stability of the judgments followed an asymmetric inverted U-shaped relation with mean relative phase, as predicted by the Haken-Kelso-Bunz model.

The objectives of this communication are to present the methods used to calculate mean absolute relative phase (MARP), deviation phase (DP) and point estimate relative phase (PRP) and compare their utility in measuring postural coordination during the performance of a serial reaching task. MARP and DP are derived from continuous relative phase time series representing the relationship between two body segments or joints during movements. MARP is a single measure used to quantify the coordination pattern and DP measures the stability of the coordination pattern. PRP also quantifies coordination patterns by measuring the relationship between the timing of maximal or minimal angular displacements of two segments within cycles of movement. Seven young adults practiced a bilateral serial reaching task 300 times over 3 days. Relative phase measures were used to evaluate inter-joint relationships for shoulder-hip (proximal) and hip-ankle (distal) postural coordination at early and late lea...

The aim of the present study was to investigate the influence of a modification of an intrinsic capacity (plantar flexor strength) on the implementation of in-phase and anti-phase mode of coordination. Analysis of hip and ankle relative phases during fore-aft tracking task was done before and after an electromyostimulation fatigue protocol on the soleus muscles. Results showed participants used exclusively in-phase and anti-phase modes of coordination, with a sudden switch from one to the other with target frequency increase. Regarding tracking tasks, fatigue induces a decrease of performance for lower frequencies, and a significant decrease of switch frequency (−0.08 Hz) for each subject. In conclusion, changes in mode of coordination implementation suggest that the in-phase mode implementation is highly linked to the strength production capacity at the ankle joint.

Introduction: The purpose of present research was the study of the effect of sensory feedback on speed of the relative phase transition in anti-phase bimanual coordination pattern across old adults. Materials and Methods: Therefore 15 intact male old adults selected in available with age range 60-70 years that were all of them hand-right. Participants started their movement on bimanual coordination device with anti-phase at frequency 0.75 Hz and was increased to it 0.25 Hz by step 5 seconds and final frequency was 5 Hz. Present task performed under 8 sensory conditions. For investigating data used repeated measures analysis of variance 2 × 2 × 2 and paired-samples t-test with Bonferroni correction for pair comparisons of the interaction effects. Results: The findings revealed that main effects of proprioception (P = 0.001), audition (P = 0.001) and two-way interaction (P = 0.022) were significant. These results implied to positive effects of audition and proprioception feedback and ...

The present study addressed the role of head movements in the coordination of the homologous upper or lower limbs in supine normal subjects. Consistent with previous research, in-phase mirror symmetrical movements were performed more accurately and consistently than anti-phase movements. However, inclusion of head movements destabilized in-phase but not anti-phase homologous limb coordination, in contrast to previous work demonstrating a higher vulnerability of anti-phase than in-phase coordination to various experimental perturbations. It was observed that the head moved in the same direction as the limbs during anti-but not during in-phase coordination. Furthermore, the interlimb patterns also affected the head rotations that were lower in spatiotemporal consistency and less consistently coupled with the limbs during in-phase than during anti-phase coordination. These findings provide new insights into the coalition of egocentric and allocentric constraints during interlimb coordination.

Optical bistability and multistability behaviors are investigated in a tripod four-level atomic configuration, including a unidirectional ring cavity. We find that optical bistability and multistability can be obtained by changing the relative phase of the driven fields and the intensity of the microwave field. In addition, we can switch optical bistability to optical multistability by adjusting the relative phase of the driven fields or vice versa, and the threshold can be controlled via changing the parameters of the scheme.

In previous studies focusing on the bargaining between two players in one-on-one interpersonal competitions, the relative phase of the velocity shows a certain characteristic. Studies have shown that the phase switches depend on the slight difference in the distance between two players. However, no study has been conducted on the series of movements from the bargaining phase to the settlement of the game. Therefore, this study aimed to quantitatively examine the characteristics of kendo from the bargaining phase to the moment of the strike, focusing on the relative phase of velocity and interpersonal distance. Participants were asked to play a kendo match, with a few restrictions. There were 80 trials, and the experiment ended when one of the participants struck the other. Based on the pattern of change in the relative phase of velocity of the waists, and the interpersonal distance, it was determined that one pattern accounted for 35% of the total trials. The pattern is that at 1-2s before the strike, the two players were in anti-phase, moving in opposite directions with an interpersonal distance of approximately 2.71m between them. Furthermore, at the time of the strike, the two players were in in-phase, moving in the same direction at an interpersonal distance of about 2.38m.

This study aimed to develop insight into the lower extremity joint coupling motions used in the maximal velocity phase of sprint running. Two-dimensional coordinate data were used to derive sagittal plane joint angle profiles of sprint running trials. Intralimb joint coupling motions were examined using a continuous relative phase (CRP) analysis. The knee-ankle (KA) coupling was more out of phase compared with the hip-knee (HK) coupling across the step phase (mean CRP: KA 89.9°; HK 34.2°) and produced a lower within-athlete CRP variability (VCRP) in stance. Touchdown (TD) produced more out-of-phase motions and a larger VCRP than toe-off. A destabilization of the lower extremity coordination pattern was considered necessary at TD to allow for the swing-to-stance transition. The key role that the KA joint motion has in the movement patterns used by healthy athletes in the maximal velocity phase of sprint running was highlighted.

Optical bistability and multistability behaviors are investigated in a tripod four-level atomic configuration, including a unidirectional ring cavity. We find that optical bistability and multistability can be obtained by changing the relative phase of the driven fields and the intensity of the microwave field. In addition, we can switch optical bistability to optical multistability by adjusting the relative phase of the driven fields or vice versa, and the threshold can be controlled via changing the parameters of the scheme.

BACKGROUND AND OBJECTIVE: Reduced joint proprioception plays an important role in the initiation and progression of the knee osteoarthritis. The present study aims to evaluate postural sway in three different positions and analyze its trends using relative indices. METHODS: This cross-sectional study was conducted among 34 patients with knee osteoarthritis and 12 healthy people using selective sampling and convenience sampling. In order to evaluate the static equilibrium indices, patients were asked to sit on the force plate in three positions; Comfort Double Leg Standing (CDLS), Romberg Standing (RS) and Near Tandem Standing (NTS). The relative values of RS CDLS and NTS CDLS were used to determine the changes in postural sway in RS and NTS positions relative to CDLS. FINDINGS: In CDLS position, the range and the standard deviation of lateral position in patients (0.019±0.010 and 0.003±0.001, respectively) was lower than healthy people (0.051±0.039 and 0.012±0.010, respectively). In...

The current study investigated the influence of resistance to motion and trial duration on the stability of bimanual coordination patterns and attentional demands. Seven participants performed in-phase and antiphase coordination patterns at a frequency of 1.5 Hz for 300 s. Resistance opposed to pronation-supination movements was manipulated. Attentional demands associated with the bimanual coordination patterns performance were measured using a probe reaction-time task. Results showed that variations in the level of resistance to motion, which induced corresponding variations in the amount of muscle activation during both the in-phase and the antiphase pattern, were associated with longer reaction time. Relative phase variability and attentional demands were higher for the antiphase pattern than for the in-phase pattern. Moreover, the attentional demands did not covary with the increase in the antiphase pattern over the trial duration. The inphase pattern remained unaffected by resistance opposed to pronation-supination movement. The present findings and the time effect are discussed according to potential alterations localized in different sites at the cortical level.

We show experimentally and theoretically how the relative phase in a short, linearly polarized microwave pulse consisting of two phase-locked frequencies is effective for strong-field quantum control of He Rydberg atoms when the frequency ratio p:q is 3:1. It is also effective when p:q 2:1 but less effective for 3:2. Parameters in our experiment are similar to those investigating quantum control of tightly bound atoms or molecules with ultrashort pulsed lasers.

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The method of controlling a spacecraft formation using mean relative states as the inputs is an effective technique if control actuation is sought to be reduced. In this paper, we extend the efficacy of this method by including the linearized J2 terms in the system dynamics and derive the linear mapping between the actual and the mean relative states. The resultant control equation has J2 related gains that are shown to improve the tracking of the states and increase system performance for a phase planebased controller performing formation maneuvering.

The existence of relative pitch perception in animals is difficult to demonstrate, since unlike humans, animals often attend to absolute rather than relative properties of sound elements. However, the results of the present study show that ferrets can be trained using relative pitch to discriminate two-tone sequences ͑rising vs. falling͒. Three ferrets were trained using a positive-reinforcement paradigm in which sequences of reference ͑one to five repeats͒ and target stimuli were presented, and animals were rewarded only when responding correctly to the target. The training procedure consisted of three training phases that successively shaped the ferrets to attend to relative pitch. In Phase-1 training, animals learned the basic task with sequences of invariant tone-pairs and could use absolute pitch information. During Phase-2 training, in order to emphasize relative cues, absolute pitch was varied each trial within a two-octave frequency range. In Phase-3 training, absolute pitch cues were removed, and only relative cue information was available to solve the task. Two ferrets successfully completed training on all three phases and achieved significant discriminative performance over the trained four-octave frequency range. These results suggest that ferrets can be trained to discern the relative pitch relationship of a sequence of tone-pairs independent of frequency.

We consider a duplicated two-level system where each two-level subsystem is driven by a strong resonant femtosecond pulse and a weak resonant femtosecond pulse connects cross transitions. Strong interference effects are induced in such a configuration leading to a modulation of the medium gain as a function of the relative phase between the pulses ͓J. C. Delagnes and M. A. Bouchene, Phys. Rev. Lett. 98, 053602 ͑2007͔͒. We study here the influence of the temporal overlap between the pulses on the dynamics of the system and the medium gain. We show that the dynamics is dominated by two competing phenomena: Light shifts ͑LS͒ induced by the driving pulse that prevails for small delays and free induction decay ͑FID͒ that prevails for large delays. LS enhance the medium gain for = / 2 and reduce it for = 0, whereas FID always leads to a decrease of the medium gain.

Paper presents the quantified assessment of stroke-affected upper extremity (UE) coordination via continuous relative phase (CRP) analysis. 14 post-stroke patients were divided into 3 groups based on the severity of impairment according to Wolf Motor Function Test (WMFT). CRP was determined based on UE kinematics parameters measured using inertial measurement units fixed on arm, forearm and hand while subjects performed designated movement. UE movement cycles were analysed based on the metrics derived from phase planes, the phase angle and CRP plots, as well as the calculated range of motions and CRP variability rates. It was found that CRP variability is associated with impairment level, i.e. it is decreasing with a higher level of dysfunction. Therefore, the CRP might serve as measurable quantity and could be valuable for supporting clinical assessment and quantifying impairment severity of UE motor functions.

Both intrapersonal and interpersonal coordination dynamics have traditionally been investigated using relative phase patterns of in-phase (ϕ = 0°) and/or anti-phase (ϕ = 180°). Numerous investigations have demonstrated that coordination tasks that require other relative phase patterns (e.g., 90°) are difficult or near impossible to perform without extended practice. Recent findings, however, have demonstrated that an individual can produce a wide range of intrapersonal bimanual patterns within a few minutes of practice when provided integrated feedback. The present experiment was designed to directly compare intraand interpersonal coordination performance and variability when provided Lissajous feedback or pacing metronome. Single participants (N = 12) and pairs of participants (N = 24, 12 pairs) were required to produce relative phase patterns between 0° and 180° in 30° increments using either pacing metronomes or Lissajous displays. The Lissajous displays involved a goal template and a cursor providing integrated feedback regarding the position of the two effectors. The results indicated both single and pairs of participants could effectively produce a large range of coordination patterns that typically act as repellers after only 6 min of practice when provided integrated feedback. However, single participants performed the in-phase coordination pattern more accurately and with less variability than paired participants, regardless of the feedback condition. These results suggest an advantage for intrapersonal coordination when performing in-phase coordination, possibly due to the stabilizing effect occurring via the neuro-muscular linkage between effectors.

Exit times for stochastic Ginzburg-Landau classical field theories with two or more coupled classical fields depend on the interval length on which the fields are defined, the potential in which the fields deterministically evolve, and the relative stiffness of the fields themselves. The latter is of particular importance in that physical applications will generally require different relative stiffnesses, but the effect of varying field stiffnesses has not heretofore been studied. In this paper, we explore the complete phase diagram of escape times as they depend on the various problem parameters. In addition to finding a transition in escape rates as the relative stiffness varies, we also observe a critical slowing down of the string method algorithm as criticality is approached.