Lattice gas automaton scheme with stochastic particle movement for a rotated fluid flow

International Nuclear Information System (INIS)

Ishiguro, Misako

2002-01-01

Lattice gas automaton (LGA) models developed so far are just for Cartesian geometries, and no direct approach to rotated fluid flows is found. In this paper, LGA method is applied to model a two-dimensional rotated flow. Several problems specific to the rotated flow are to be solved: hexagonal lattice geometry to effectively identify the neighbors, boundary condition for irregular walls, multi-speed scheme to represent angular-oriented fluid velocity υ θ ≅γω, shape of macroscopic domain for statistics, formula to obtain macroscopic quantities such as density and mean fluid velocities, application method of Fermi-Dirac function to the initial particle arrangement. For this purpose, FHP-I type hexagonal lattice model is revised and a new LGA model with stochastic particle movement is proposed. The results of the trial calculation are shown. It is also investigated whether or not the underlying microscopic Boolean equations newly introduced leads to Navier-Stokes equation. (author)

Visual perception of axes of head rotation

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Arnoldussen, D. M.; Goossens, J.; van den Berg, A. V.

2013-01-01

Registration of ego-motion is important to accurately navigate through space. Movements of the head and eye relative to space are registered through the vestibular system and optical flow, respectively. Here, we address three questions concerning the visual registration of self-rotation. (1) Eye-in-head movements provide a link between the motion signals received by sensors in the moving eye and sensors in the moving head. How are these signals combined into an ego-rotation percept? We combined optic flow of simulated forward and rotational motion of the eye with different levels of eye-in-head rotation for a stationary head. We dissociated simulated gaze rotation and head rotation by different levels of eye-in-head pursuit. We found that perceived rotation matches simulated head- not gaze-rotation. This rejects a model for perceived self-rotation that relies on the rotation of the gaze line. Rather, eye-in-head signals serve to transform the optic flow's rotation information, that specifies rotation of the scene relative to the eye, into a rotation relative to the head. This suggests that transformed visual self-rotation signals may combine with vestibular signals. (2) Do transformed visual self-rotation signals reflect the arrangement of the semi-circular canals (SCC)? Previously, we found sub-regions within MST and V6+ that respond to the speed of the simulated head rotation. Here, we re-analyzed those Blood oxygenated level-dependent (BOLD) signals for the presence of a spatial dissociation related to the axes of visually simulated head rotation, such as have been found in sub-cortical regions of various animals. Contrary, we found a rather uniform BOLD response to simulated rotation along the three SCC axes. (3) We investigated if subject's sensitivity to the direction of the head rotation axis shows SCC axes specifcity. We found that sensitivity to head rotation is rather uniformly distributed, suggesting that in human cortex, visuo-vestibular integration is

Visual perception of axes of head rotation

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David Mattijs Arnoldussen

2013-02-01

Full Text Available Registration of ego-motion is important to accurately navigate through space. Movements of the head and eye relative to space are registered through the vestibular system and optical flow, respectively. Here, we address three questions concerning the visual registration of self-rotation. 1. Eye-in-head movements provide a link between the motion signals received by sensors in the moving eye and sensors in the moving head. How are these signals combined into an ego-rotation percept? We combined optic flow of simulated forward and rotational motion of the eye with different levels of eye-in-head rotation for a stationary head. We dissociated simulated gaze rotation and head rotation by different levels of eye-in-head pursuit.We found that perceived rotation matches simulated head- not gaze-rotation. This rejects a model for perceived self-rotation that relies on the rotation of the gaze line. Rather, eye-in-head signals serve to transform the optic flow’s rotation information, that specifies rotation of the scene relative to the eye, into a rotation relative to the head. This suggests that transformed visual self-rotation signals may combine with vestibular signals.2. Do transformed visual self-rotation signals reflect the arrangement of the semicircular canals (SCC? Previously, we found sub-regions within MST and V6+ that respond to the speed of the simulated head rotation. Here, we re-analyzed those BOLD signals for the presence of a spatial dissociation related to the axes of visually simulated head rotation, such as have been found in sub-cortical regions of various animals. Contrary, we found a rather uniform BOLD response to simulated rotation along the three SCC axes.3. We investigated if subject’s sensitivity to the direction of the head rotation axis shows SCC axes specifcity. We found that sensitivity to head rotation is rather uniformly distributed, suggesting that in human cortex, visuo-vestibular integration is not arranged into

Slow movement execution in event-related potentials (P300).

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Naruse, Kumi; Sakuma, Haruo; Hirai, Takane

2002-02-01

We examined whether slow movement execution has an effect on cognitive and information processing by measuring the P300 component. 8 subjects performed a continuous slow forearm rotational movement using 2 task speeds. Slow (a 30-50% decrease from the subject's Preferred speed) and Very Slow (a 60-80% decrease). The mean coefficient of variation for rotation speed under Very Slow was higher than that under Slow, showing that the subjects found it difficult to perform the Very Slow task smoothly. The EEG score of alpha-1 (8-10 Hz) under Slow Condition was increased significantly more than under the Preferred Condition; however, the increase under Very Slow was small when compared with Preferred. After performing the task. P300 latency under Very Slow increased significantly as compared to that at pretask. Further, P300 amplitude decreased tinder both speed conditions when compared to that at pretask, and a significant decrease was seen under the Slow Condition at Fz, whereas the decrease under the Very Slow Condition was small. These differences indicated that a more complicated neural composition and an increase in subjects' attention might have been involved when the task was performed under the Very Slow Condition. We concluded that slow movement execution may have an influence on cognitive function and may depend on the percentage of decrease from the Preferred speed of the individual.

Preschool children adapt grasping movements to upcoming object manipulations: Evidence from a dial rotation task.

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Herbort, Oliver; Büschelberger, Juliane; Janczyk, Markus

2018-03-01

In adults, the motor plans for object-directed grasping movements reflects the anticipated requirements of intended future object manipulations. This prospective mode of planning has been termed second-order planning. Surprisingly, second-order planning is thought to be fully developed only by 10 years of age, when children master seemingly more complex motor skills. In this study, we tested the hypothesis that already 5- and 6-year-old children consistently use second-order planning but that this ability does not become apparent in tasks that are traditionally used to probe it. We asked 5- and 6-year-olds and adults to grasp and rotate a circular dial in a clockwise or counterclockwise direction. Although children's grasp selections were less consistent on an intra- and inter-individual level than adults' grasp selections, all children adjusted their grasps to the upcoming dial rotations. By contrast, in an also administered bar rotation task, only a subset of children adjusted their grasps to different bar rotations, thereby replicating previous results. The results indicate that 5- and 6-year-olds consistently use second-order planning in a dial rotation task, although this ability does not become apparent in bar rotation tasks. Copyright © 2017 Elsevier Inc. All rights reserved.

Vection is the main contributor to motion sickness induced by visual yaw rotation: Implications for conflict and eye movement theories.

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Suzanne A E Nooij

Full Text Available This study investigated the role of vection (i.e., a visually induced sense of self-motion, optokinetic nystagmus (OKN, and inadvertent head movements in visually induced motion sickness (VIMS, evoked by yaw rotation of the visual surround. These three elements have all been proposed as contributing factors in VIMS, as they can be linked to different motion sickness theories. However, a full understanding of the role of each factor is still lacking because independent manipulation has proven difficult in the past. We adopted an integrative approach to the problem by obtaining measures of potentially relevant parameters in four experimental conditions and subsequently combining them in a linear mixed regression model. To that end, participants were exposed to visual yaw rotation in four separate sessions. Using a full factorial design, the OKN was manipulated by a fixation target (present/absent, and vection strength by introducing a conflict in the motion direction of the central and peripheral field of view (present/absent. In all conditions, head movements were minimized as much as possible. Measured parameters included vection strength, vection variability, OKN slow phase velocity, OKN frequency, the number of inadvertent head movements, and inadvertent head tilt. Results show that VIMS increases with vection strength, but that this relation varies among participants (R2 = 0.48. Regression parameters for vection variability, head and eye movement parameters were not significant. These results may seem to be in line with the Sensory Conflict theory on motion sickness, but we argue that a more detailed definition of the exact nature of the conflict is required to fully appreciate the relationship between vection and VIMS.

Preliminary discussion on possible genesis of crustal rotation, its impact on geotectonic evolution and its relation to large-scale metallogeny in Hunan province and adjacent regions

International Nuclear Information System (INIS)

Shu Xiaojing

2005-01-01

Hunan province and adjacent regions show ring-form distribution features both on surface geologic structure and geophysical field. Such features might result from the rotation movement of the earth crust and exert serious impact on the geotectonic evolution and large-scale metallogeny in Hunan province and adjacent regions. This paper makes a preliminary discussion on the possible genesis of such rotation movement, as well as the associated series of geologic processes and its relation to large-scale metallogeny in Hunan province and adjacent regions. (authors)

Laser scanning-based recognition of rotational movements on a deep seated gravitational instability: The Cinque Torri case (North-Eastern Italian Alps)

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Viero, Alessia; Teza, Giordano; Massironi, Matteo; Jaboyedoff, Michel; Galgaro, Antonio

2010-10-01

The Cinque Torri group (Cortina d'Ampezzo, Italy) is an articulated system of unstable carbonatic rock monoliths located in a very important tourism area and therefore characterized by a significant risk. The instability phenomena involved represent an example of lateral spreading developed over a larger deep seated gravitational slope deformation (DSGSD) area. After the recent fall of a monolith of more than 10 000 m 3, a scientific study was initiated to monitor the more unstable sectors and to characterize the past movements as a fundamental tool for predicting future movements and hazard assessment. To achieve greater insight on the ongoing lateral spreading process, a method for a quantitative analysis of rotational movements associated with the lateral spreading has been developed, applied and validated. The method is based on: i) detailed geometrical characterization of the area by means of laser scanner techniques; ii) recognition of the discontinuity sets and definition of a reference frame for each set, iii) correlation between the obtained reference frames related to a specific sector and a stable external reference frame, and iv) determination of the 3D rotations in terms of Euler angles to describe the present settlement of the Cinque Torri system with respect to the surrounding stable areas. In this way, significant information on the processes involved in the fragmentation and spreading of a former dolomitic plateau into different rock cliffs has been gained. The method is suitable to be applied to similar case studies.

Rotating Quark Stars in General Relativity

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Enping Zhou

2018-03-01

Full Text Available We have built quasi-equilibrium models for uniformly rotating quark stars in general relativity. The conformal flatness approximation is employed and the Compact Object CALculator (cocal code is extended to treat rotating stars with surface density discontinuity. In addition to the widely used MIT bag model, we have considered a strangeon star equation of state (EoS, suggested by Lai and Xu, that is based on quark clustering and results in a stiff EoS. We have investigated the maximum mass of uniformly rotating axisymmetric quark stars. We have also built triaxially deformed solutions for extremely fast rotating quark stars and studied the possible gravitational wave emission from such configurations.

Analysis of Movement, Orientation and Rotation-Based Sensing for Phone Placement Recognition

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Ozlem Durmaz Incel

2015-10-01

Full Text Available Phone placement, i.e., where the phone is carried/stored, is an important source of information for context-aware applications. Extracting information from the integrated smart phone sensors, such as motion, light and proximity, is a common technique for phone placement detection. In this paper, the efficiency of an accelerometer-only solution is explored, and it is investigated whether the phone position can be detected with high accuracy by analyzing the movement, orientation and rotation changes. The impact of these changes on the performance is analyzed individually and both in combination to explore which features are more efficient, whether they should be fused and, if yes, how they should be fused. Using three different datasets, collected from 35 people from eight different positions, the performance of different classification algorithms is explored. It is shown that while utilizing only motion information can achieve accuracies around 70%, this ratio increases up to 85% by utilizing information also from orientation and rotation changes. The performance of an accelerometer-only solution is compared to solutions where linear acceleration, gyroscope and magnetic field sensors are used, and it is shown that the accelerometer-only solution performs as well as utilizing other sensing information. Hence, it is not necessary to use extra sensing information where battery power consumption may increase. Additionally, I explore the impact of the performed activities on position recognition and show that the accelerometer-only solution can achieve 80% recognition accuracy with stationary activities where movement data are very limited. Finally, other phone placement problems, such as in-pocket and on-body detections, are also investigated, and higher accuracies, ranging from 88% to 93%, are reported, with an accelerometer-only solution.

Rotations in a Vertebrate Setting

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McCollum, Gin

2003-05-01

Rotational movements of the head are often considered to be measured in a single three dimensional coordinate system implemented by the semicircular canals of the vestibular system of the inner ear. However, the vertebrate body -- including the nervous system -- obeys rectangular symmetries alien to rotation groups. At best, nervous systems mimic the physical rotation group in a fragmented way, only partially reintegrating physical movements in whole organism responses. The vestibular canal reference frame is widely used in nervous systems, for example by eye movements. It is used to some extent even in the cerebrum, as evidenced by the remission of hemineglect -- in which half of space is ignored -- when the vestibular system is stimulated. However, reintegration of space by the organism remains incomplete. For example, compensatory eye movements (which in most cases aid visual fixation) may disagree with conscious self-motion perception. In addition, movement-induced nausea, illusions, and cue-free perceptions demonstrate symmetry breaking or incomplete spatial symmetries. As part of a long-term project to investigate rotation groups in nervous systems, we have analyzed the symmetry group of a primary vestibulo-spinal projection.

Gender differences in rotation of the shank during single-legged drop landing and its relation to rotational muscle strength of the knee.

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Kiriyama, Shinya; Sato, Haruhiko; Takahira, Naonobu

2009-01-01

Increased shank rotation during landing has been considered to be one of the factors for noncontact anterior cruciate ligament injuries in female athletes. There have been no known gender differences in rotational knee muscle strength, which is expected to inhibit exaggerated shank rotation. Women have less knee external rotator strength than do men. Lower external rotator strength is associated with increased internal shank rotation at the time of landing. Controlled laboratory study. One hundred sixty-nine healthy young subjects (81 female and 88 male; age, 17.0 +/- 1.0 years) volunteered to participate in this study. The subjects performed single-legged drop landings from a 20-cm height. Femoral and shank kinematics were measured using a 3D optoelectronic tracking system during the drop landings, and then the joint angles around the knee (flexion/extension, valgus/varus, and internal/external rotation) were calculated. The maximal isometric rotational muscle strength of the knee was measured at 30 degrees of knee flexion in a supine position using a dynamometer. The female subjects had significantly less external shank rotation strength than did the male subjects (P external rotation strength and the peak shank internal rotation angle during landing (r = -0.322, P external rotator strength. This may lead to large shank internal rotation movement during the single-legged drop landing. Improving strength training of the external rotator muscle may help decrease the rates of anterior cruciate ligament injury in female athletes.

Detection of movement intention from single-trial movement-related cortical potentials

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Niazi, Imran Khan; Jiang, Ning; Tiberghien, Olivier; Feldbæk Nielsen, Jørgen; Dremstrup, Kim; Farina, Dario

2011-10-01

Detection of movement intention from neural signals combined with assistive technologies may be used for effective neurofeedback in rehabilitation. In order to promote plasticity, a causal relation between intended actions (detected for example from the EEG) and the corresponding feedback should be established. This requires reliable detection of motor intentions. In this study, we propose a method to detect movements from EEG with limited latency. In a self-paced asynchronous BCI paradigm, the initial negative phase of the movement-related cortical potentials (MRCPs), extracted from multi-channel scalp EEG was used to detect motor execution/imagination in healthy subjects and stroke patients. For MRCP detection, it was demonstrated that a new optimized spatial filtering technique led to better accuracy than a large Laplacian spatial filter and common spatial pattern. With the optimized spatial filter, the true positive rate (TPR) for detection of movement execution in healthy subjects (n = 15) was 82.5 ± 7.8%, with latency of -66.6 ± 121 ms. Although TPR decreased with motor imagination in healthy subject (n = 10, 64.5 ± 5.33%) and with attempted movements in stroke patients (n = 5, 55.01 ± 12.01%), the results are promising for the application of this approach to provide patient-driven real-time neurofeedback.

Quantification of the 3D relative movement of external marker sets vs. bones based on magnetic resonance imaging.

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Sangeux, M; Marin, F; Charleux, F; Dürselen, L; Ho Ba Tho, M C

2006-11-01

Most in vivo knee kinematic analyses are based on external markers attached to the shank and the thigh. Literature data show that markers positioning and soft tissues artifacts affect the kinematic parameters of the bones true movement. Most of the techniques of quantification used were invasive. The aim of the present study was to develop and apply a non-invasive methodology to compute the relative movement between the bones and the markers. Magnetic resonance imaging acquisitions were performed on the right knee of eleven volunteers without knee injury. The subjects were equipped with external magnetic resonance imaging-compatible marker sets. A foot drive device allowed the subjects to perform an actively loaded knee extension. The whole volume of the subject's knee was processed for four sequentially held knee flexion positions during the knee movement. The bones and external marker sets geometry were reconstructed from magnetic resonance imaging images. Then a registration algorithm was applied to the bones and the relative movement of the thigh and shank marker sets with respect to their underlying bones was computed. The protocol resulted in a good geometrical accuracy and reproducibility. Marker sets movement differ from that of the bones with a maximum of 22 mm in translation and 15 degrees in rotation and it affects the knee kinematics. Marker sets relative movement modify the knee movement finite helical axes direction (range 10-35 degrees ) and localization (range 0-40 mm). The methodology developed can evaluate external marker set system to be used for kinematic analysis in a clinical environment.

Determination of a sagittal plane axis of rotation for a dynamic office chair.

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Bauer, C M; Rast, F M; Böck, C; Kuster, R P; Baumgartner, D

2018-10-01

This study investigated the location of the axis of rotation in sagittal plane movement of the spine in a free sitting condition to adjust the kinematics of a mobile seat for a dynamic chair. Dynamic office chairs are designed to avoid continuous isometric muscle activity, and to facilitate increased mobility of the back during sitting. However, these chairs incorporate increased upper body movement which could distract office workers from the performance of their tasks. A chair with an axis of rotation above the seat would facilitate a stable upper back during movements of the lower back. The selection of a natural kinematic pattern is of high importance in order to match the properties of the spine. Twenty-one participants performed four cycles of flexion and extension of the spine during an upper arm hang on parallel bars. The location of the axis of rotation relative to the seat was estimated using infrared cameras and reflective skin markers. The median axis of rotation across all participants was located 36 cm above the seat for the complete movement and 39 cm for both the flexion and extension phases, each with an interquartile range of 20 cm. There was no significant effect of the movement direction on the location of the axis of rotation and only a weak, non-significant correlation between body height and the location of the axis of rotation. Individual movement patterns explained the majority of the variance. The axis of rotation for a spinal flexion/extension movement is located above the seat. The recommended radius for a guide rail of a mobile seat is between 36 cm and 39 cm. Copyright © 2018 Elsevier Ltd. All rights reserved.

Movement-related neuromagnetic fields in preschool age children.

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Cheyne, Douglas; Jobst, Cecilia; Tesan, Graciela; Crain, Stephen; Johnson, Blake

2014-09-01

We examined sensorimotor brain activity associated with voluntary movements in preschool children using a customized pediatric magnetoencephalographic system. A videogame-like task was used to generate self-initiated right or left index finger movements in 17 healthy right-handed subjects (8 females, ages 3.2-4.8 years). We successfully identified spatiotemporal patterns of movement-related brain activity in 15/17 children using beamformer source analysis and surrogate MRI spatial normalization. Readiness fields in the contralateral sensorimotor cortex began ∼0.5 s prior to movement onset (motor field, MF), followed by transient movement-evoked fields (MEFs), similar to that observed during self-paced movements in adults, but slightly delayed and with inverted source polarities. We also observed modulation of mu (8-12 Hz) and beta (15-30 Hz) oscillations in sensorimotor cortex with movement, but with different timing and a stronger frequency band coupling compared to that observed in adults. Adult-like high-frequency (70-80 Hz) gamma bursts were detected at movement onset. All children showed activation of the right superior temporal gyrus that was independent of the side of movement, a response that has not been reported in adults. These results provide new insights into the development of movement-related brain function, for an age group in which no previous data exist. The results show that children under 5 years of age have markedly different patterns of movement-related brain activity in comparison to older children and adults, and indicate that significant maturational changes occur in the sensorimotor system between the preschool years and later childhood. Copyright © 2014 Wiley Periodicals, Inc.

Clinical identification of the simple sleep-related movement disorders.

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Walters, Arthur S

2007-04-01

Simple sleep-related movement disorders must be distinguished from daytime movement disorders that persist during sleep, sleep-related epilepsy, and parasomnias, which are generally characterized by activity that appears to be simultaneously complex, goal-directed, and purposeful but is outside the conscious awareness of the patient and, therefore, inappropriate. Once it is determined that the patient has a simple sleep-related movement disorder, the part of the body affected by the movement and the age of the patient give clues as to which sleep-related movement disorder is present. In some cases, all-night polysomnography with accompanying video may be necessary to make the diagnosis. Hypnic jerks (ie, sleep starts), bruxism, rhythmic movement disorder (ie, head banging/body rocking), and nocturnal leg cramps are discussed in addition to less well-appreciated disorders such as benign sleep myoclonus of infancy, excessive fragmentary myoclonus, and hypnagogic foot tremor/alternating leg muscle activation.

Unsteady flow field in a mini VAWT with relative rotation blades: analysis of temporal results

International Nuclear Information System (INIS)

Bayeul-Lainé, A C; Simonet, S; Bois, G

2013-01-01

The present wind turbine is a small one which can be used on roofs or in gardens. This turbine has a vertical axis. Each turbine blade combines a rotating movement around its own axis and around the main rotor axis. Due to this combination of movements, flow around this turbine is highly unsteady and needs to be modelled by unsteady calculation. The present work is an extended study starting in 2009. The benefits of combined rotating blades have been shown. The performance coefficient of this kind of turbine is very good for some blade stagger angles. Spectral analysis of unsteady results on specific points in the domain and temporal forces on blades was already presented for elliptic blades. The main aim here is to compare two kinds of blades in case of the best performances

Multivariate spectral-analysis of movement-related EEG data

International Nuclear Information System (INIS)

Andrew, C. M.

1997-01-01

The univariate method of event-related desynchronization (ERD) analysis, which quantifies the temporal evolution of power within specific frequency bands from electroencephalographic (EEG) data recorded during a task or event, is extended to an event related multivariate spectral analysis method. With this method, time courses of cross-spectra, phase spectra, coherence spectra, band-averaged coherence values (event-related coherence, ERCoh), partial power spectra and partial coherence spectra are estimated from an ensemble of multivariate event-related EEG trials. This provides a means of investigating relationships between EEG signals recorded over different scalp areas during the performance of a task or the occurrence of an event. The multivariate spectral analysis method is applied to EEG data recorded during three different movement-related studies involving discrete right index finger movements. The first study investigates the impact of the EEG derivation type on the temporal evolution of interhemispheric coherence between activity recorded at electrodes overlying the left and right sensorimotor hand areas during cued finger movement. The question results whether changes in coherence necessarily reflect changes in functional coupling of the cortical structures underlying the recording electrodes. The method is applied to data recorded during voluntary finger movement and a hypothesis, based on an existing global/local model of neocortical dynamics, is formulated to explain the coherence results. The third study applies partial spectral analysis too, and investigates phase relationships of, movement-related data recorded from a full head montage, thereby providing further results strengthening the global/local hypothesis. (author)

Saccadic Movement Strategy in Common Cuttlefish (Sepia officinalis).

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Helmer, Desiree; Geurten, Bart R H; Dehnhardt, Guido; Hanke, Frederike D

2016-01-01

Most moving animals segregate their locomotion trajectories in short burst like rotations and prolonged translations, to enhance distance information from optic flow, as only translational, but not rotational optic flow holds distance information. Underwater, optic flow is a valuable source of information as it is in the terrestrial habitat, however, so far, it has gained only little attention. To extend the knowledge on underwater optic flow perception and use, we filmed the movement pattern of six common cuttlefish (Sepia officinalis) with a high speed camera in this study. In the subsequent analysis, the center of mass of the cuttlefish body was manually traced to gain thrust, slip, and yaw of the cuttlefish movements over time. Cuttlefish indeed performed short rotations, saccades, with rotational velocities up to 343°/s. They clearly separated rotations from translations in line with the saccadic movement strategy documented for animals inhabiting the terrestrial habitat as well as for the semiaquatic harbor seals before. However, this separation only occurred during fin motion. In contrast, during jet propelled swimming, the separation between rotational and translational movements and thus probably distance estimation on the basis of the optic flow field is abolished in favor of high movement velocities. In conclusion, this study provides first evidence that an aquatic invertebrate, the cuttlefish, adopts a saccadic movement strategy depending on the behavioral context that could enhance the information gained from optic flow.

Low torque hydrodynamic lip geometry for bi-directional rotation seals

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Dietle, Lannie L [Houston, TX; Schroeder, John E [Richmond, TX

2009-07-21

A hydrodynamically lubricating geometry for the generally circular dynamic sealing lip of rotary seals that are employed to partition a lubricant from an environment. The dynamic sealing lip is provided for establishing compressed sealing engagement with a relatively rotatable surface, and for wedging a film of lubricating fluid into the interface between the dynamic sealing lip and the relatively rotatable surface in response to relative rotation that may occur in the clockwise or the counter-clockwise direction. A wave form incorporating an elongated dimple provides the gradual convergence, efficient impingement angle, and gradual interfacial contact pressure rise that are conducive to efficient hydrodynamic wedging. Skewed elevated contact pressure zones produced by compression edge effects provide for controlled lubricant movement within the dynamic sealing interface between the seal and the relatively rotatable surface, producing enhanced lubrication and low running torque.

Rotational motion in nuclei

International Nuclear Information System (INIS)

Bohr, A.

1976-01-01

Nuclear structure theories are reviewed concerned with nuclei rotational motion. The development of the deformed nucleus model facilitated a discovery of rotational spectra of nuclei. Comprehensive verification of the rotational scheme and a successful classification of corresponding spectra stimulated investigations of the rotational movement dynamics. Values of nuclear moments of inertia proved to fall between two marginal values corresponding to rotation of a solid and hydrodynamic pattern of an unrotating flow, respectively. The discovery of governing role of the deformation and a degree of a symmetry violence for determining rotational degrees of freedon is pointed out to pave the way for generalization of the rotational spectra

Distinct eye movement patterns enhance dynamic visual acuity

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Palidis, Dimitrios J.; Wyder-Hodge, Pearson A.; Fooken, Jolande; Spering, Miriam

2017-01-01

Dynamic visual acuity (DVA) is the ability to resolve fine spatial detail in dynamic objects during head fixation, or in static objects during head or body rotation. This ability is important for many activities such as ball sports, and a close relation has been shown between DVA and sports expertise. DVA tasks involve eye movements, yet, it is unclear which aspects of eye movements contribute to successful performance. Here we examined the relation between DVA and the kinematics of smooth pursuit and saccadic eye movements in a cohort of 23 varsity baseball players. In a computerized dynamic-object DVA test, observers reported the location of the gap in a small Landolt-C ring moving at various speeds while eye movements were recorded. Smooth pursuit kinematics—eye latency, acceleration, velocity gain, position error—and the direction and amplitude of saccadic eye movements were linked to perceptual performance. Results reveal that distinct eye movement patterns—minimizing eye position error, tracking smoothly, and inhibiting reverse saccades—were related to dynamic visual acuity. The close link between eye movement quality and DVA performance has important implications for the development of perceptual training programs to improve DVA. PMID:28187157

Distinct eye movement patterns enhance dynamic visual acuity.

Science.gov (United States)

Palidis, Dimitrios J; Wyder-Hodge, Pearson A; Fooken, Jolande; Spering, Miriam

2017-01-01

Dynamic visual acuity (DVA) is the ability to resolve fine spatial detail in dynamic objects during head fixation, or in static objects during head or body rotation. This ability is important for many activities such as ball sports, and a close relation has been shown between DVA and sports expertise. DVA tasks involve eye movements, yet, it is unclear which aspects of eye movements contribute to successful performance. Here we examined the relation between DVA and the kinematics of smooth pursuit and saccadic eye movements in a cohort of 23 varsity baseball players. In a computerized dynamic-object DVA test, observers reported the location of the gap in a small Landolt-C ring moving at various speeds while eye movements were recorded. Smooth pursuit kinematics-eye latency, acceleration, velocity gain, position error-and the direction and amplitude of saccadic eye movements were linked to perceptual performance. Results reveal that distinct eye movement patterns-minimizing eye position error, tracking smoothly, and inhibiting reverse saccades-were related to dynamic visual acuity. The close link between eye movement quality and DVA performance has important implications for the development of perceptual training programs to improve DVA.

Effect of slow, small movement on the vibration-evoked kinesthetic illusion.

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Cordo, P J; Gurfinkel, V S; Brumagne, S; Flores-Vieira, C

2005-12-01

The study reported in this paper investigated how vibration-evoked illusions of joint rotation are influenced by slow (0.3 degrees /s), small (2-4 degrees ) passive rotation of the joint. Normal human adults (n=15) matched the perceived position of the left ("reference") arm with the right ("matching") arm while vibration (50 pps, 0.5 mm) was applied for 30 s to the relaxed triceps brachii of the reference arm. Both arms were constrained to rotate horizontally at the elbow. Three experimental conditions were investigated: (1) vibration of the stationary reference arm, (2) slow, small passive extension or flexion of the reference arm during vibration, and (3) slow, small passive extension or flexion of the reference arm without vibration. Triceps brachii vibration at 50 pps induced an illusion of elbow flexion. The movement illusion began after several seconds, relatively fast to begin with and gradually slowing down to a stop. On average, triceps vibration produced illusory motion at an average latency of 6.3 s, amplitude of 9.7 degrees , velocity of 0.6 degrees /s, and duration of 16.4 s. During vibration, slow, small ( approximately 0.3 degrees /s, 1.3 degrees ) passive rotations of the joint dramatically enhanced, stopped, or reversed the direction of illusory movement, depending on the direction of the passive joint rotation. However, the subjects' perceptions of these passive elbow rotations were exaggerated: 2-3 times the size of the actual movement. In the absence of vibration, the subjects accurately reproduced these passive joint rotations. We discuss whether the exaggerated perception of slow, small movement during vibration is better explained by contributions of non muscle spindle Ia afferents or by changes in the mechanical transmission of vibration to the receptor.

THE RADIO ACTIVITY-ROTATION RELATION OF ULTRACOOL DWARFS

International Nuclear Information System (INIS)

McLean, M.; Berger, E.; Reiners, A.

2012-01-01

We present a new radio survey of about 100 late-M and L dwarfs undertaken with the Very Large Array. The sample was chosen to explore the role of rotation in the radio activity of ultracool dwarfs. As part of the survey we discovered radio emission from three new objects, 2MASS J 0518113 – 310153 (M6.5), 2MASS J 0952219 – 192431 (M7), and 2MASS J 1314203 + 132001 (M7), and made an additional detection of LP 349-25 (M8). Combining the new sample with results from our previous studies and from the literature, we compile the largest sample to date of ultracool dwarfs with radio observations and measured rotation velocities (167 objects). In the spectral type range M0-M6 we find a radio activity-rotation relation, with saturation at L rad /L bol ≈ 10 –7.5 above vsin i ≈ 5 km s –1 , similar to the relation in Hα and X-rays. However, at spectral types ∼> M7 the ratio of radio to bolometric luminosity increases significantly regardless of rotation velocity, and the scatter in radio luminosity increases. In particular, while the most rapid rotators (vsin i ∼> 20 km s –1 ) exhibit 'super-saturation' in X-rays and Hα, this effect is not seen in the radio. We also find that ultracool dwarfs with vsin i ∼> 20 km s –1 have a higher radio detection fraction by about a factor of three compared to objects with vsin i ∼ –1 . When measured in terms of the Rossby number (Ro), the radio activity-rotation relation follows a single trend and with no apparent saturation from G to L dwarfs and down to Ro ∼ 10 –3 ; in X-rays and Hα there is clear saturation at Ro ∼ rad /R 2 * ) as a function of Ro. The continued role of rotation in the overall level of radio activity and in the fraction of active sources, and the single trend of L rad /L bol and L rad /R 2 * as a function of Ro from G to L dwarfs, indicates that rotation effects are important in regulating the topology or strength of magnetic fields in at least some fully convective dwarfs. The fact that

Conjunct rotation: Codman's paradox revisited.

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Wolf, Sebastian I; Fradet, Laetitia; Rettig, Oliver

2009-05-01

This contribution mathematically formalizes Codman's idea of conjunct rotation, a term he used in 1934 to describe a paradoxical phenomenon arising from a closed-loop arm movement. Real (axial) rotation is distinguished from conjunct rotation. For characterizing the latter, the idea of reference vector fields is developed to define the neutral axial position of the humerus for any given orientation of its long axis. This concept largely avoids typical coordinate singularities arising from decomposition of 3D joint motion and therefore can be used for postural (axial) assessment of the shoulder joint both clinically and in sports science in almost the complete accessible range of motion. The concept, even though algebraic rather complex, might help to get an easier and more intuitive understanding of axial rotation of the shoulder in complex movements present in daily life and in sports.

Axial movements are relatively preserved with respect to limb movements in aphasic patients.

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Hanlon, R E; Mattson, D; Demery, J A; Dromerick, A W

1998-12-01

Apraxia is commonly manifested during the acute stage following left hemisphere cerebrovascular accident and typically co-occurs with aphasia. We examined 30 acute stroke patients with aphasia and apraxia in order to determine if such patients show evidence of preservation of selective subclasses of movements. Although Geschwind noted the preservation of axial movements to command in aphasic apraxic patients, his views were subsequently refuted. However, we found that aphasic apraxic patients of varying degrees of severity, including patients with global aphasia, showed relative preservation of axial movements to command and imitation. Theoretical interpretations and implications for acute neurologic rehabilitation are discussed.

Towards age/rotation/magnetic activity relation with seismology

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Mathur Savita

2015-01-01

Full Text Available The knowledge of stellar ages directly impacts the characterization of a planetary system as it puts strong constraints on the moment when the system was born. Unfortunately, the determination of precise stellar ages is a very difficult task. Different methods can be used to do so (based on isochrones or chemical element abundances but they usually provide large uncertainties. During its evolution a star goes through processes leading to loss of angular momentum but also changes in its magnetic activity. Building rotation, magnetic, age relations would be an asset to infer stellar ages model independently. Several attempts to build empirical relations between rotation and age (namely gyrochronology were made with a focus on cluster stars where the age determination is easier and for young stars on the main sequence. For field stars, we can now take advantage of high-precision photometric observations where we can perform asteroseismic analyses to improve the accuracy of stellar ages. Furthermore, the variability in the light curves allow us to put strong constraints on the stellar rotation and magnetic activity. By combining these precise measurements, we are on the way of understanding and improving relations between magnetic activity, rotation, and age, in particular at different stages of stellar evolution. I will review the status on gyrochronology relationships based on observations of young cluster stars. Then I will focus on solar-like stars and describe the inferences on stellar ages, rotation, and magnetism that can be provided by high-quality photometric observations such as the ones of the Kepler mission, in particular through asteroseismic analyses.

Elbow joint stability in relation to forced external rotation

DEFF Research Database (Denmark)

Deutch, S.R.; Jensen, S.L.; Olsen, B.S.

2003-01-01

The objective of this study was to evaluate the osseous constraint related to forced forearm external rotation as the initial stage in a posterior elbow dislocation. Six joint specimens without soft tissues were examined in a joint analysis system developed for simulation of dislocation. The osse......The objective of this study was to evaluate the osseous constraint related to forced forearm external rotation as the initial stage in a posterior elbow dislocation. Six joint specimens without soft tissues were examined in a joint analysis system developed for simulation of dislocation...... external forearm rotation until the point of maximal torque decreased from a maximum in full extension to a minimum at 30 degrees of elbow flexion (P =.03). The elbow in a slightly flexed position, varus stress, and forearm external rotation trauma might be the important biomechanical factors...

Rotation in relativity and the propagation of light

International Nuclear Information System (INIS)

Kajari, E.; Buser, M.; Feiler, C.; Schleich, W.P.

2009-01-01

We compare and contrast the different points of view of rotation in general relativity, put forward by March, Thirring and Lense, and Goedel. Our analysis relies on two tools: 1) the Sagnac effect which allows to measure rotations of a coordinate system or induced by the curvature of spacetime, and 2) computer visualizations which bring out the alien features of the Goedel Universe. In order to keep the paper self-contained, we summarize in several appendices crucial ingredients of the mathematical tools used in general relativity. In this way, ou lecture notes should be accessible to researchers familiar with the basic elements of tensor calculus and general relativity.

Extended I-Love relations for slowly rotating neutron stars

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Gagnon-Bischoff, Jérémie; Green, Stephen R.; Landry, Philippe; Ortiz, Néstor

2018-03-01

Observations of gravitational waves from inspiralling neutron star binaries—such as GW170817—can be used to constrain the nuclear equation of state by placing bounds on stellar tidal deformability. For slowly rotating neutron stars, the response to a weak quadrupolar tidal field is characterized by four internal-structure-dependent constants called "Love numbers." The tidal Love numbers k2el and k2mag measure the tides raised by the gravitoelectric and gravitomagnetic components of the applied field, and the rotational-tidal Love numbers fo and ko measure those raised by couplings between the applied field and the neutron star spin. In this work, we compute these four Love numbers for perfect fluid neutron stars with realistic equations of state. We discover (nearly) equation-of-state independent relations between the rotational-tidal Love numbers and the moment of inertia, thereby extending the scope of I-Love-Q universality. We find that similar relations hold among the tidal and rotational-tidal Love numbers. These relations extend the applications of I-Love universality in gravitational-wave astronomy. As our findings differ from those reported in the literature, we derive general formulas for the rotational-tidal Love numbers in post-Newtonian theory and confirm numerically that they agree with our general-relativistic computations in the weak-field limit.

Simultaneous search for symmetry-related molecules in cross-rotation functions

International Nuclear Information System (INIS)

Yeates, T.O.

1989-01-01

In a typical cross-rotation function, the Patterson function of a single search molecule is compared with an observed Patterson function, which contains a set of symmetry-related intramolecular vector sets. In principle, it is better to search for the symmetry-related molecules simultaneously, and Nordman has reported success with an algorithm of this type. In this paper, the differences between the ordinary search and a simultaneous search are investigated, and it is shown that the combined presence of crystallographic symmetry and approximate symmetry of a search model may lead to significant bias in conventional rotation functions. The nature and magnitude of this symmetry bias are discussed. An efficient algorithm is derived for generating a modified unbiased cross-rotation function map from conventional rotation functions. Two examples are described that demonstrate improvement in the quality of the rotation function maps and the ability to obtain physically meaningful correlation coefficients. (orig.)

A Review of Techniques for Detection of Movement Intention Using Movement-Related Cortical Potentials

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Aqsa Shakeel

2015-01-01

Full Text Available The movement-related cortical potential (MRCP is a low-frequency negative shift in the electroencephalography (EEG recording that takes place about 2 seconds prior to voluntary movement production. MRCP replicates the cortical processes employed in planning and preparation of movement. In this study, we recapitulate the features such as signal’s acquisition, processing, and enhancement and different electrode montages used for EEG data recoding from different studies that used MRCPs to predict the upcoming real or imaginary movement. An authentic identification of human movement intention, accompanying the knowledge of the limb engaged in the performance and its direction of movement, has a potential implication in the control of external devices. This information could be helpful in development of a proficient patient-driven rehabilitation tool based on brain-computer interfaces (BCIs. Such a BCI paradigm with shorter response time appears more natural to the amputees and can also induce plasticity in brain. Along with different training schedules, this can lead to restoration of motor control in stroke patients.

Motor Processes in Children's Mental Rotation

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Frick, Andrea; Daum, Moritz M.; Walser, Simone; Mast, Fred W.

2009-01-01

Previous studies with adult human participants revealed that motor activities can influence mental rotation of body parts and abstract shapes. In this study, we investigated the influence of a rotational hand movement on mental rotation performance from a developmental perspective. Children at the age of 5, 8, and 11 years and adults performed a…

Signalling properties of identified deep cerebellar nuclear neurons related to eye and head movements in the alert cat.

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Gruart, A; Delgado-García, J M

1994-07-01

1. The spike activity of deep cerebellar nuclear neurons was recorded in the alert cat during spontaneous and during vestibularly and visually induced eye movements. 2. Neurons were classified according to their location in the nuclei, their antidromic activation from projection sites, their sensitivity to eye position and velocity during spontaneous eye movements, and their responses to vestibular and optokinetic stimuli. 3. Type I EPV (eye position and velocity) neurons were located mainly in the posterior part of the fastigial nucleus and activated antidromically almost exclusively from the medial longitudinal fasciculus close to the oculomotor complex. These neurons, reported here for the first time, increased their firing rate during saccades and eye fixations towards the contralateral hemifield. Their position sensitivity to eye fixations in the horizontal plane was 5.3 +/- 2.6 spikes s-1 deg-1 (mean +/- S.D.). Eye velocity sensitivity during horizontal saccades was 0.71 +/- 0.52 spikes s-1 deg-1 s-1. Variability of their firing rate during a given eye fixation was higher than that shown by abducens motoneurons. 4. Type I EPV neurons increased their firing rate during ipsilateral head rotations at 0.5 Hz with a mean phase lead over eye position of 95.3 +/- 9.5 deg. They were also activated by contralateral optokinetic stimulation at 30 deg s-1. Their sensitivity to eye position and velocity in the horizontal plane during vestibular and optokinetic stimuli yielded values similar to those obtained for spontaneous eye movements. 5. Type II neurons were located in both fastigial and dentate nuclei and were activated antidromically from the restiform body, the medial longitudinal fasciculus close to the oculomotor complex, the red nucleus and the pontine nuclei. Type II neurons were not related to spontaneous eye movements. These neurons increased their firing rate in response to contralateral head rotation and during ipsilateral optokinetic stimulation, and

Building a Climate Movement Through Relational Organizing

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Bethany M Divakaran

2017-06-01

Full Text Available Community organizing is a process for achieving social change through the mobilization of resources and the formation of collective identity. Relational community organizing is a particular approach to developing new leaders and building organizational capacity for sustaining a powerful movement, and is especially relevant in the climate justice movement because relationships serve to bring actors from isolation and despair toward communal identity and hopeful action. Minnesota Interfaith Power & Light (MNIPL is a community organization that is using relational organizing to activate faith communities to take action on climate change. This paper describes the design and first phase of evaluation of MNIPL’s Movement Builder Program, a networked distributed leadership model that uses peer mentors to increase the efficacy of new organizers. Can a peer-to-peer network increase the leverage of organizers? Will supportive relationships move people to increased action and to develop the leadership of others? We provide an introduction to this inquiry as well as the foundational frameworks and historical context of this new approach.

Cybersickness in the presence of scene rotational movements along different axes.

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Lo, W T; So, R H

2001-02-01

Compelling scene movements in a virtual reality (VR) system can cause symptoms of motion sickness (i.e., cybersickness). A within-subject experiment has been conducted to investigate the effects of scene oscillations along different axes on the level of cybersickness. Sixteen male participants were exposed to four 20-min VR simulation sessions. The four sessions used the same virtual environment but with scene oscillations along different axes, i.e., pitch, yaw, roll, or no oscillation (speed: 30 degrees/s, range: +/- 60 degrees). Verbal ratings of the level of nausea were taken at 5-min intervals during the sessions and sickness symptoms were also measured before and after the sessions using the Simulator Sickness Questionnaire (SSQ). In the presence of scene oscillation, both nausea ratings and SSQ scores increased at significantly higher rates than with no oscillation. While individual participants exhibited different susceptibilities to nausea associated with VR simulation containing scene oscillations along different rotational axes, the overall effects of axis among our group of 16 randomly selected participants were not significant. The main effects of, and interactions among, scene oscillation, duration, and participants are discussed in the paper.

Goal-selection and movement-related conflict during bimanual reaching movements.

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Diedrichsen, Jörn; Grafton, Scott; Albert, Neil; Hazeltine, Eliot; Ivry, Richard B

2006-12-01

Conflict during bimanual movements can arise during the selection of movement goals or during movement planning and execution. We demonstrate a behavioral and neural dissociation of these 2 types of conflict. During functional magnetic resonance imaging scanning, participants performed bimanual reaching movements with symmetric (congruent) or orthogonal (incongruent) trajectories. The required movements were indicated either spatially, by illuminating the targets, or symbolically, using centrally presented letters. The processing of symbolic cues led to increased activation in a left hemisphere network including the intraparietal sulcus, premotor cortex, and inferior frontal gyrus. Reaction time cost for incongruent movements was substantially larger for symbolic than for spatial cues, indicating that the cost was primarily associated with the selection and assignment of movement goals, demands that are minimized when goals are directly specified by spatial cues. This goal-selection conflict increased activity in the pre-supplementary motor area and cingulate motor areas. Both cueing conditions led to larger activation for incongruent movements in the convexity of the superior parietal cortex, bilaterally, making this region a likely neural site for conflict that arises during the planning and execution of bimanual movements. These results suggest distinct neural loci for 2 forms of constraint on our ability to perform bimanual reaching movements.

Influence of spontaneous rhythm on movement-related cortical potential

DEFF Research Database (Denmark)

Yao, Lin; Chen, Mei Lin; Sheng, Xinjun

2017-01-01

We have recently developed an associative Brain-Computer Interface (BCI) for neuromodulation in chronic and acute stroke patients that leads to functional improvements. The control signal is the movement related cortical potential (MRCP) that develops prior to movement execution. The MRCP increases...

The functional role of dorso-lateral premotor cortex during mental rotation: an event-related fMRI study separating cognitive processing steps using a novel task paradigm.

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Lamm, Claus; Windischberger, Christian; Moser, Ewald; Bauer, Herbert

2007-07-15

Subjects deciding whether two objects presented at angular disparity are identical or mirror versions of each other usually show response times that linearly increase with the angle between objects. This phenomenon has been termed mental rotation. While there is widespread agreement that parietal cortex plays a dominant role in mental rotation, reports concerning the involvement of motor areas are less consistent. From a theoretical point of view, activation in motor areas suggests that mental rotation relies upon visuo-motor rather than visuo-spatial processing alone. However, the type of information that is processed by motor areas during mental rotation remains unclear. In this study we used event-related fMRI to assess whether activation in parietal and dorsolateral premotor areas (dPM) during mental rotation is distinctively related to processing spatial orientation information. Using a newly developed task paradigm we explicitly separated the processing steps (encoding, mental rotation proper and object matching) required by mental rotation tasks and additionally modulated the amount of spatial orientation information that had to be processed. Our results show that activation in dPM during mental rotation is not strongly modulated by the processing of spatial orientation information, and that activation in dPM areas is strongest during mental rotation proper. The latter finding suggests that dPM is involved in more generalized processes such as visuo-spatial attention and movement anticipation. We propose that solving mental rotation tasks is heavily dependent upon visuo-motor processes and evokes neural processing that may be considered as an implicit simulation of actual object rotation.

Quantification of vestibular-induced eye movements in zebrafish larvae

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Mo Weike

2010-09-01

Full Text Available Abstract Background Vestibular reflexes coordinate movements or sensory input with changes in body or head position. Vestibular-evoked responses that involve the extraocular muscles include the vestibulo-ocular reflex (VOR, a compensatory eye movement to stabilize retinal images. Although an angular VOR attributable to semicircular canal stimulation was reported to be absent in free-swimming zebrafish larvae, recent studies reveal that vestibular-induced eye movements can be evoked in zebrafish larvae by both static tilts and dynamic rotations that tilt the head with respect to gravity. Results We have determined herein the basis of sensitivity of the larval eye movements with respect to vestibular stimulus, developmental stage, and sensory receptors of the inner ear. For our experiments, video recordings of larvae rotated sinusoidally at 0.25 Hz were analyzed to quantitate eye movements under infrared illumination. We observed a robust response that appeared as early as 72 hours post fertilization (hpf, which increased in amplitude over time. Unlike rotation about an earth horizontal axis, rotation about an earth vertical axis at 0.25 Hz did not evoke eye movements. Moreover, vestibular-induced responses were absent in mutant cdh23 larvae and larvae lacking anterior otoliths. Conclusions Our results provide evidence for a functional vestibulo-oculomotor circuit in 72 hpf zebrafish larvae that relies upon sensory input from anterior/utricular otolith organs.

EEG Oscillations Are Modulated in Different Behavior-Related Networks during Rhythmic Finger Movements.

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Seeber, Martin; Scherer, Reinhold; Müller-Putz, Gernot R

2016-11-16

Sequencing and timing of body movements are essential to perform motoric tasks. In this study, we investigate the temporal relation between cortical oscillations and human motor behavior (i.e., rhythmic finger movements). High-density EEG recordings were used for source imaging based on individual anatomy. We separated sustained and movement phase-related EEG source amplitudes based on the actual finger movements recorded by a data glove. Sustained amplitude modulations in the contralateral hand area show decrease for α (10-12 Hz) and β (18-24 Hz), but increase for high γ (60-80 Hz) frequencies during the entire movement period. Additionally, we found movement phase-related amplitudes, which resembled the flexion and extension sequence of the fingers. Especially for faster movement cadences, movement phase-related amplitudes included high β (24-30 Hz) frequencies in prefrontal areas. Interestingly, the spectral profiles and source patterns of movement phase-related amplitudes differed from sustained activities, suggesting that they represent different frequency-specific large-scale networks. First, networks were signified by the sustained element, which statically modulate their synchrony levels during continuous movements. These networks may upregulate neuronal excitability in brain regions specific to the limb, in this study the right hand area. Second, movement phase-related networks, which modulate their synchrony in relation to the movement sequence. We suggest that these frequency-specific networks are associated with distinct functions, including top-down control, sensorimotor prediction, and integration. The separation of different large-scale networks, we applied in this work, improves the interpretation of EEG sources in relation to human motor behavior. EEG recordings provide high temporal resolution suitable to relate cortical oscillations to actual movements. Investigating EEG sources during rhythmic finger movements, we distinguish sustained from

A study of human performance in a rotating environment

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Green, J. A.; Peacock, J. L.; Holm, A. P.

1971-01-01

Consideration is given to the lack of sufficient data relative to the response of man to the attendant oculovestibular stimulations induced by multi-directional movement of an individual within the rotating environment to provide the required design criteria. This was done to determine the overall impact of artificial gravity simulations on potential design configurations and crew operational procedures. Gross locomotion and fine motor performance were evaluated. Results indicate that crew orientation, rotational rates, vehicle design configurations, and operational procedures may be used to reduce the severity of the adverse effects of the Coriolis and cross-coupled angular accelerations acting on masses moving within a rotating environment. Results further indicate that crew selection, motivation, and short-term exposures to the rotating environment may be important considerations for future crew indoctrination and training programs.

Numerical results in a vertical wind axis turbine with relative rotating blades

Energy Technology Data Exchange (ETDEWEB)

Bayeul-Laine, Annie-Claude; Dockter, Aurore; Simonet, Sophie; Bois, Gerard [Arts et Metiers PARISTECH (France)

2011-07-01

The use of wind energy to produce electricity through wind turbines has spread world-wide. The quantity of electricity produced is affected by numerous factors such as wind speed and direction and turbine design; the aim of this paper is to assess the influence of different blades on the performance of a turbine. This study was performed on a turbine in which the blades have a rotating movement, each around its own axis and around the turbine's axis. Unsteady simulations were carried out with several blade stagger angles and one wind speed and 2 different blade geometries were used for 4 rotational speeds. Results showed that the studied turbine gave better performance than vertical axis wind turbines and that blade sketch, blade speed ratios, and blade stagger angle were important influences on the performance. This study showed that this kind of turbine has the potential to achieve good performance but that further work needs to be done.

Contextual effects on motion perception and smooth pursuit eye movements.

Science.gov (United States)

Spering, Miriam; Gegenfurtner, Karl R

2008-08-15

Smooth pursuit eye movements are continuous, slow rotations of the eyes that allow us to follow the motion of a visual object of interest. These movements are closely related to sensory inputs from the visual motion processing system. To track a moving object in the natural environment, its motion first has to be segregated from the motion signals provided by surrounding stimuli. Here, we review experiments on the effect of the visual context on motion processing with a focus on the relationship between motion perception and smooth pursuit eye movements. While perception and pursuit are closely linked, we show that they can behave quite distinctly when required by the visual context.

Rotation of vertically oriented objects during earthquakes

Science.gov (United States)

Hinzen, Klaus-G.

2012-10-01

Vertically oriented objects, such as tombstones, monuments, columns, and stone lanterns, are often observed to shift and rotate during earthquake ground motion. Such observations are usually limited to the mesoseismal zone. Whether near-field rotational ground motion components are necessary in addition to pure translational movements to explain the observed rotations is an open question. We summarize rotation data from seven earthquakes between 1925 and 2009 and perform analog and numeric rotation testing with vertically oriented objects. The free-rocking motion of a marble block on a sliding table is disturbed by a pulse in the direction orthogonal to the rocking motion. When the impulse is sufficiently strong and occurs at the `right' moment, it induces significant rotation of the block. Numeric experiments of a free-rocking block show that the initiation of vertical block rotation by a cycloidal acceleration pulse applied orthogonal to the rocking axis depends on the amplitude of the pulse and its phase relation to the rocking cycle. Rotation occurs when the pulse acceleration exceeds the threshold necessary to provoke rocking of a resting block, and the rocking block approaches its equilibrium position. Experiments with blocks subjected to full 3D strong motion signals measured during the 2009 L'Aquila earthquake confirm the observations from the tests with analytic ground motions. Significant differences in the rotational behavior of a monolithic block and two stacked blocks exist.

Examining Age-Related Movement Representations for Sequential (Fine-Motor) Finger Movements

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Gabbard, Carl; Cacola, Priscila; Bobbio, Tatiana

2011-01-01

Theory suggests that imagined and executed movement planning relies on internal models for action. Using a chronometry paradigm to compare the movement duration of imagined and executed movements, we tested children aged 7-11 years and adults on their ability to perform sequential finger movements. Underscoring this tactic was our desire to gain a…

RELATION BETWEEN THE LATENT MOTOR DIMENSIONS RESPONSIBLE FOR MOVEMENTS OF STUDENTS IN ACQUIRING THE MOTOR TESTS

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Viktor Mitrevski

2012-09-01

Full Text Available The research has been carried out on a sample defined by the population of students who attended regularly their training classes in primary school in the Republic of Macedonia (from the region of Prespa and Pelagonia and the Republic of Serbia (from the region of Banat, municipality Kikinda. The total number of entities is 179, of which 124 are from Macedonia, and 55 – from Serbia who are eight-grade students, aged 14-15 (± 3 months. The aim of the study is to establish the relation between the results and obtained marks in motor tests with the latent motor dimensions responsible for the movements of students. By using factor analysis – varimax rotation, there is determined the effect and relation between the marks obtained in acquiring the motor tests for estimating the explosive power, start speed, and precisity of students.

Kinematics of fast cervical rotations in persons with chronic neck pain: a cross-sectional and reliability study.

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Röijezon, Ulrik; Djupsjöbacka, Mats; Björklund, Martin; Häger-Ross, Charlotte; Grip, Helena; Liebermann, Dario G

2010-09-27

Assessment of sensorimotor function is useful for classification and treatment evaluation of neck pain disorders. Several studies have investigated various aspects of cervical motor functions. Most of these have involved slow or self-paced movements, while few have investigated fast cervical movements. Moreover, the reliability of assessment of fast cervical axial rotation has, to our knowledge, not been evaluated before. Cervical kinematics was assessed during fast axial head rotations in 118 women with chronic nonspecific neck pain (NS) and compared to 49 healthy controls (CON). The relationship between cervical kinematics and symptoms, self-rated functioning and fear of movement was evaluated in the NS group. A sub-sample of 16 NS and 16 CON was re-tested after one week to assess the reliability of kinematic variables. Six cervical kinematic variables were calculated: peak speed, range of movement, conjunct movements and three variables related to the shape of the speed profile. Together, peak speed and conjunct movements had a sensitivity of 76% and a specificity of 78% in discriminating between NS and CON, of which the major part could be attributed to peak speed (NS: 226 ± 88°/s and CON: 348 ± 92°/s, p conjunct movements was poor. Peak speed of fast cervical axial rotations is reduced in people with chronic neck pain, and even further reduced in subjects with concomitant low back pain. Fast cervical rotation test seems to be a reliable and valid tool for assessment of neck pain disorders on group level, while a rather large between subject variation and overlap between groups calls for caution in the interpretation of individual assessments.

Principal direction of inertia for 3D trajectories from patient-specific TMJ movement.

Science.gov (United States)

Kim, Dae-Seung; Choi, Soon-Chul; Lee, Sam-Sun; Heo, Min-Suk; Huh, Kyung-Hoe; Hwang, Soon-Jung; Kim, Seong-Ha; Yi, Won-Jin

2013-03-01

Accurate simulation and evaluation of mandibular movement is fundamental for the analysis of functional changes and effects of the mandible and maxilla before and after surgical treatments. We applied principal axes of inertia to the three-dimensional (3D) trajectories generated by patient-specific simulations of TMJ movements for the functional evaluations of mandible movement. Three-dimensional movements of the mandible and the maxilla were tracked based on a patient-specific splint and an optical tracking system. The dental occlusion recorded on the sprint provided synchronization for initial movement in the tracking and the simulation phases. The translation and rotation recorded during movement tracking was applied sequentially to the mandibular model in relation to a fixed maxilla model. The sequential 3D positions of selected landmarks on the mandible were calculated based on the reference coordinate system. The landmarks selected for analysis were bilateral condyles and pogonion points. The moment of inertia tensor was calculated with respect to the 3D trajectory points. Using the unit vectors along the principal axes derived from the tensor matrix, α, β and γ rotations around z-, y- and x-axes were determined to represent the principal directions as principal rotations respectively. The γ direction showed the higher standard deviation, variation of directions, than other directions at all the landmarks. The mandible movement has larger kinematic redundancy in the γ direction than α and β during mouth opening and closing. Principal directions of inertia would be applied to analyzing the changes in angular motion of trajectories introduced by mandibular shape changes from surgical treatments and also to the analysis of the influence of skeletal deformities on mandibular movement asymmetry. Copyright © 2012 Elsevier Ltd. All rights reserved.

Adaptive panoramic tomography with a circular rotational movement for the formation of multifocal image layers

Energy Technology Data Exchange (ETDEWEB)

Kim, D. S.; Cho, H. S.; Park, Y. O.; Je, U. K.; Hong, D. K.; Choi, S. I.; Koo, Y. S. [Yonsei University, Wonju (Korea, Republic of)

2012-02-15

Panoramic radiography with which only structures within a certain image layer are in focus and others out of focus on the panoramic image has become a popular imaging technique especially in dentistry. However, the major drawback to the technique is a mismatch between the structures to be focused and the predefined image layer mainly due to the various shapes and sizes of dental arches and/or to malpositioning of the patient. These result in image quality typically inferior to that obtained using intraoral radiographic techniques. In this paper, to overcome these difficulties, we suggest a new panoramic reconstruction algorithm, the so-called adaptive panoramic tomography (APT), capable of reconstructing multifocal image layers with no additional exposure. In order to verify the effectiveness of the proposed algorithm, we performed systematic simulation studies with a circular rotational movement and investigated the image performance.

Rotational synkineses of occiput and atlas on lateral inclination

Energy Technology Data Exchange (ETDEWEB)

Jirout, J.

1981-02-01

An X-ray analysis was performed with regard to the question of synkinetic rotational movements of occiput and atlas on lateral inclination of the head and neck. It was found that the frequent synkinetic rotation of the head from the side of inclination can be taken for a stereotype that is ten times more frequent than the rotation towards the side of inclination. However, it does not represent an essential or indispensable feature of the synkinetic reaction. The associated rotation of the atlas from the side of inclination cannot be looked upon as a normal and constant element of the synkinetic response on lateral inclination, as it does not occur in nearly one-half of cases. Moreover, these studies have shown that the rotational movement between occiput and atlas is possible not only in the final stage of maximum forced rotation of the head, but that it belongs to normal dynamic features of the synkinetic response on lateral inclination of the head and neck.

Rotational synkineses of occiput and atlas on lateral inclination

International Nuclear Information System (INIS)

Jirout, J.

1981-01-01

An X-ray analysis was performed with regard to the question of synkinetic rotational movements of occiput and atlas on lateral inclination of the head and neck. It was found that the frequent synkinetic rotation of the head from the side of inclination can be taken for a stereotype that is ten times more frequent than the rotation towards the side of inclination. However, it does not represent an essential or indispensable feature of the synkinetic reaction. The associated rotation of the atlas from the side of inclination cannot be looked upon as a normal and constant element of the synkinetic response on lateral inclination, as it does not occur in nearly one-half of cases. Moreover, these studies have shown that the rotational movement between occiput and atlas is possible not only in the final stage of maximum forced rotation of the head, but that it belongs to normal dynamic features of the synkinetic response on lateral inclination of the head and neck. (orig.)

Analysis of EEG Related Saccadic Eye Movement

Science.gov (United States)

Funase, Arao; Kuno, Yoshiaki; Okuma, Shigeru; Yagi, Tohru

Our final goal is to establish the model for saccadic eye movement that connects the saccade and the electroencephalogram(EEG). As the first step toward this goal, we recorded and analyzed the saccade-related EEG. In the study recorded in this paper, we tried detecting a certain EEG that is peculiar to the eye movement. In these experiments, each subject was instructed to point their eyes toward visual targets (LEDs) or the direction of the sound sources (buzzers). In the control cases, the EEG was recorded in the case of no eye movemens. As results, in the visual experiments, we found that the potential of EEG changed sharply on the occipital lobe just before eye movement. Furthermore, in the case of the auditory experiments, similar results were observed. In the case of the visual experiments and auditory experiments without eye movement, we could not observed the EEG changed sharply. Moreover, when the subject moved his/her eyes toward a right-side target, a change in EEG potential was found on the right occipital lobe. On the contrary, when the subject moved his/her eyes toward a left-side target, a sharp change in EEG potential was found on the left occipital lobe.

Visualization of Spatio-Temporal Relations in Movement Event Using Multi-View

Science.gov (United States)

Zheng, K.; Gu, D.; Fang, F.; Wang, Y.; Liu, H.; Zhao, W.; Zhang, M.; Li, Q.

2017-09-01

Spatio-temporal relations among movement events extracted from temporally varying trajectory data can provide useful information about the evolution of individual or collective movers, as well as their interactions with their spatial and temporal contexts. However, the pure statistical tools commonly used by analysts pose many difficulties, due to the large number of attributes embedded in multi-scale and multi-semantic trajectory data. The need for models that operate at multiple scales to search for relations at different locations within time and space, as well as intuitively interpret what these relations mean, also presents challenges. Since analysts do not know where or when these relevant spatio-temporal relations might emerge, these models must compute statistical summaries of multiple attributes at different granularities. In this paper, we propose a multi-view approach to visualize the spatio-temporal relations among movement events. We describe a method for visualizing movement events and spatio-temporal relations that uses multiple displays. A visual interface is presented, and the user can interactively select or filter spatial and temporal extents to guide the knowledge discovery process. We also demonstrate how this approach can help analysts to derive and explain the spatio-temporal relations of movement events from taxi trajectory data.

VISUALIZATION OF SPATIO-TEMPORAL RELATIONS IN MOVEMENT EVENT USING MULTI-VIEW

Directory of Open Access Journals (Sweden)

K. Zheng

2017-09-01

Full Text Available Spatio-temporal relations among movement events extracted from temporally varying trajectory data can provide useful information about the evolution of individual or collective movers, as well as their interactions with their spatial and temporal contexts. However, the pure statistical tools commonly used by analysts pose many difficulties, due to the large number of attributes embedded in multi-scale and multi-semantic trajectory data. The need for models that operate at multiple scales to search for relations at different locations within time and space, as well as intuitively interpret what these relations mean, also presents challenges. Since analysts do not know where or when these relevant spatio-temporal relations might emerge, these models must compute statistical summaries of multiple attributes at different granularities. In this paper, we propose a multi-view approach to visualize the spatio-temporal relations among movement events. We describe a method for visualizing movement events and spatio-temporal relations that uses multiple displays. A visual interface is presented, and the user can interactively select or filter spatial and temporal extents to guide the knowledge discovery process. We also demonstrate how this approach can help analysts to derive and explain the spatio-temporal relations of movement events from taxi trajectory data.

Identification and risk estimation of movement strategies during cutting maneuvers.

Science.gov (United States)

David, Sina; Komnik, Igor; Peters, Markus; Funken, Johannes; Potthast, Wolfgang

2017-12-01

Approximately 70% of anterior cruciate ligament (ACL) injuries occur in non-contact situations during cutting and landing maneuvers. Parameters such as footstrike patterns and trunk orientation were found to influence ACL relevant knee loading, however, the relationship between the whole body movement and injury risk is debated. This study identifies whole body movement strategies that increase injury risk, and provides training recommendations to reduce this risk or enable a save return to sports after injury. Experimental cross-sectional study design. Three dimensional movement analysis was carried out to investigate 50 participants performing anticipated 90° cutting maneuvers. To identify and characterize movement strategies, footstrike pattern, knee valgus moment, knee internal rotation moment, angle of attack, shoulder and pelvis axis were analyzed using statistical parametric mapping. Three different movement strategies were identified. One strategy included rearfoot striking in combination with a relatively upright body position which generated higher knee joint loads than the second strategy, forefoot striking in combination with more backwards leaning and pre-rotation of the trunk towards the new movement direction. A third strategy combined forefoot striking with less preorientation which increased the ACL relevant knee joint load compared to the second strategy. The identified movement strategies clearly pre-determine the injury risk during non-contact situations with the third strategy as the most unfavorable one. Compared to the study of isolated parameters, the analysis of the whole body movement allowed for detailed separation of more risky from less risky cutting strategies. These results give practical recommendations for the prevention of ACL injury. Copyright © 2017 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Lateralization of event-related potential effects during mental rotation of polygons.

Science.gov (United States)

Pellkofer, Julia; Jansen, Petra; Heil, Martin

2012-07-11

Numerous studies have shown that there is an amplitude modulation of the late positivity depending on the angular disparity during mental rotation performance. However, almost all of these studies used characters as stimulus material, whereas studies with different stimuli are rare. In the present experiment, 35 participants were instructed to rotate polygons mentally. Most importantly, with this stimulus material, the well-known event-related potential effects were also present at posterior electrode leads. Interestingly, the amplitude modulation were found to be larger and more reliable over left than over right posterior electrode leads, a finding reported previously for characters as stimuli, although not consistently. Thus, the present data suggest that the left lateralization of event-related potential effects during mental rotation of characters might not be because of their 'verbal nature', but might suggest a stronger involvement of the left parietal cortex during mental rotation per se, a suggestion that needs to be addressed with methods providing a higher spatial resolution.

Validity of eyeball estimation for range of motion during the cervical flexion rotation test compared to an ultrasound-based movement analysis system.

Science.gov (United States)

Schäfer, Axel; Lüdtke, Kerstin; Breuel, Franziska; Gerloff, Nikolas; Knust, Maren; Kollitsch, Christian; Laukart, Alex; Matej, Laura; Müller, Antje; Schöttker-Königer, Thomas; Hall, Toby

2018-08-01

Headache is a common and costly health problem. Although pathogenesis of headache is heterogeneous, one reported contributing factor is dysfunction of the upper cervical spine. The flexion rotation test (FRT) is a commonly used diagnostic test to detect upper cervical movement impairment. The aim of this cross-sectional study was to investigate concurrent validity of detecting high cervical ROM impairment during the FRT by comparing measurements established by an ultrasound-based system (gold standard) with eyeball estimation. Secondary aim was to investigate intra-rater reliability of FRT ROM eyeball estimation. The examiner (6 years experience) was blinded to the data from the ultrasound-based device and to the symptoms of the patients. FRT test result (positive or negative) was based on visual estimation of range of rotation less than 34° to either side. Concurrently, range of rotation was evaluated using the ultrasound-based device. A total of 43 subjects with headache (79% female), mean age of 35.05 years (SD 13.26) were included. According to the International Headache Society Classification 23 subjects had migraine, 4 tension type headache, and 16 multiple headache forms. Sensitivity and specificity were 0.96 and 0.89 for combined rotation, indicating good concurrent reliability. The area under the ROC curve was 0.95 (95% CI 0.91-0.98) for rotation to both sides. Intra-rater reliability for eyeball estimation was excellent with Fleiss Kappa 0.79 for right rotation and left rotation. The results of this study indicate that the FRT is a valid and reliable test to detect impairment of upper cervical ROM in patients with headache.

Relation between radio luminosity and rotation for late-type stars

International Nuclear Information System (INIS)

Stewart, R.T.; Innis, J.L.; Slee, O.B.; Nelson, G.J.; Wright, A.E.

1988-01-01

A relation is found between peak radio luminosities measured at 8 GHz and the rotational velocity of 51 late-type F, G, and K stars (including the sun). The sample includes both single stars and active components of close binary systems, with equatorial surface velocities ranging from 1 to 100 km/s. A gyrosynchrotron source model originally developed to explain solar microwave bursts could explain the relation. The main parameter depending on rotation rate is the filling factor, i.e., the fraction of the stellar surface and corona occupied by intense magnetic fields. As the rotation speed increases, the scale size of the coronal structures emitting microwave gyrosynchrotron radiation increases, and there is a corresponding increase in the area of the surface covered by intense starspot magnetic fields. However, the peak magnetic field of the starspots probably does not increase significantly above observed sunspot values. 47 references

Level of movement skills and dexterity in relation to movement activities of pre-school children in their ordinary lives

OpenAIRE

Kubátová, Šárka

2014-01-01

and keywords The level of movement skills and dexterity in relation to movement activities of pre- school children in their ordinary lives. The diploma thesis deals with the issue of movement activity of pre-school children. Movement activities are vital part of healthy life, especially for children. It should be an essential part of every activity, no matter if it is sport, game, relaxation or just a walk to school. It should be a common part of every pre-school child daily programme. The ac...

An immediate effect of axial neck rotation training with real time visual feedback using a smartphone inclinometer on improvement in axial neck rotation function.

Science.gov (United States)

Park, Kyue-Nam; Kwon, Oh-Yun; Kim, Si-Hyun; Jeon, In-Cheol

2017-03-01

The purpose of this study was to compare the immediate effects of axial neck rotation training (Axi-NRT) with and without real-time visual feedback (VF) using a smartphone inclinometer on the range of motion (ROM) for axial neck rotation and the onset of compensatory neck lateral bending and extension during active neck rotation. Twenty participants with restricted ROM for neck rotation but no neck pain (21.1 ± 1.6 years and 8 males, 12 females) were recruited for Axi-NRT with VF, and twenty age- and gender-matched participants with restricted ROM for neck rotation were recruited for Axi-NRT without VF. Changes in ROM for neck rotation and the onset time of compensatory neck movement during active neck rotation were measured using an electromagnetic tracking system. Axi-NRT with VF was more effective in increasing ROM for neck rotation and decreasing and delaying the onset of compensatory neck movements during active neck rotation compared with Axi-NRT without VF. Repeated Axi-NRT using VF is useful to educate participants in maintaining the axis of the cervical spine and to increase ROM for axial neck rotation with less compensatory neck motion in participants with a restricted range of neck rotations.

Structure and stability of rapidly rotating fluid bodies in general relativity. II. The structure of uniformly rotating pseudopolytropes

International Nuclear Information System (INIS)

Butterworth, E.M.

1976-01-01

A method is described for obtaining numerical solutions to the exact Einstein field equations that represent uniformly rotating perfect fluid bodies which are stationary and obey equations of state of the form (pressure) proportional (energy density) 1+1 //subn/. Sequences parametrized by the rate of rotation are generated for polytropic indices n between 0.5 and 3 and for varying strengths of relativity. All are found to terminate at surface velocities which are approximately 10 percent or more of the velocity of light. The configurations considered here are probably at least as relativistic as any stable astrophysical object in uniform rotation now thought to exist, but the phenomenon of an ergoregion appears in none of them and probably is absent in actual stars if magnetic viscosity or some other mechanism can induce rigid rotation

Power and momentum relations in rotating magnetic field current drive

Energy Technology Data Exchange (ETDEWEB)

Hugrass, W N [Flinders Univ. of South Australia, Bedford Park. School of Physical Sciences

1984-01-01

The use of rotating magnetic fields (RMF) to drive steady currents in plasmas involves a transfer of energy and angular momentum from the radio frequency source feeding the rotating field coils to the plasma. The power-torque relationships in RMF systems are discussed and the analogy between RMF current drive and the polyphase induction motor is explained. The general relationship between the energy and angular momentum transfer is utilized to calculate the efficiency of the RMF plasma current drive. It is found that relatively high efficiencies can be achieved in RMF current drive because of the low phase velocity and small slip between the rotating field and the electron fluid.

Effect of chaotic movements of nanoparticles for nanofluid heat transfer augmentation by molecular dynamics simulation

International Nuclear Information System (INIS)

Cui, Wenzheng; Shen, Zhaojie; Yang, Jianguo; Wu, Shaohua

2015-01-01

Through Molecular Dynamics simulation, the chaotic movements of nanoparticles in base fluid are investigated. Based on the simulated results of translational and rotational velocities of nanoparticles, the effect of nanoparticle movements for heat transfer in nanofluids is discussed. Furthermore, the influence of nanoparticle movements for the base fluid is studied. The fluid near a nanoparticle is divided into three levels: (1) absorption layer, (2) rotating fluid, and (3) spherical existential space, or called rotating fluid element. And the microscopic structure of nanofluid which is composed of countless rotating fluid elements is proposed. - Highlights: • The orders of magnitude of translational and rotational motions for nanoparticles are given. • The microscopic structure around a nanoparticle is proposed. • Mechanisms of heat transfer enhancement in nanofluids are discussed

A new relation of parameters of Bohr-Mottelson rotational spectra formula

International Nuclear Information System (INIS)

Li Mingliang; Xu Fuxin

2003-01-01

With the first three terms of Harris formula included and Mottelson's method followed, a new relation of the parameters of Bohr-Mottelson rotational spectra formula is brought forward. Superdeformed bands of even-even nuclei and normal deformed bands of nuclei in actinide and rare-earth are fitted with four-parameter Bohr-Mottelson rotational spectra formula. The relations of the parameters A, B, C, D are studied. The result show, for normal deformed bands, the new relation approach the experiment value in the same degree as the relation deduced from ab formula, but for superdeformed bands, the new relation is closer to the experiment than the relation deduced from ab formula. Three-parameter Harris formula may have better convergence than two-parameter Harris formula

NEW TYPE OF ELASTIC ROTATIONAL WAVES IN GEO-MEDIUM AND VORTEX GEODYNAMICS

Directory of Open Access Journals (Sweden)

Alexander V. Vikulin

2010-01-01

Full Text Available Natural-science concepts of rotational movements and the ‘lumpy’ structure of medium are reviewed with a focus on key aspects. Through using torsional traps for hunting and «implementing» mechanical torque for ignition, Homo sapiens developed to man. Vortex movements «impregnated» in spiral structures of shells and torsional movements of toothy whales and fish were intuitively perceived by man as major stable movements of the environment. Based on the above, the ancient philosophy established the concept of the uniform world represented by atomic («noncuttable» structure of medium and vortex movements of ether. Based on conclusive arguments stated by R. Dekart, H. Helmgolz, Lord Kelvin and others within the framework of classical physics and in the first half of the 20th century by scientists in quantum physics and cosmogony, both «quantum structure» («lumpiness» and rotation («vorticity» are integral features of matter – space – time throughout the whole range from elementary particles to galaxies and galactic clusters.Nowadays researchers in natural sciences, particularly in the Earth sciences, call attention again to the problem of structure of matter and its movements. In the 1920s, Chinese geologist Li Siguang established fundamentals of vortex geodynamics. In the second half of the 20th century, Li Siguan’s concepts were developed by geologists O.I. Slenzak and I.V. Melekestsev. Geologist A.V. Peive, mechanic L.I. Sedov and physicist M.A. Sadovsky put forward a concept of block structure of the geo-medium (geological and geophysical medium and proposed a justified assumption that such blocks can move by own torque. This method of movement is confirmed by results of geological and tectonophysical studies, as well as instrumental geophysical measurements obtained from a variety of stations and focal zones of strong earthquakes. Many researchers, including W. Elsasser and V.N. Nikolaevsky, develop fundamentals of

Effects of Sustained Otolith-Only Stimulation on Post-Rotational Nystagmus.

Science.gov (United States)

Shaikh, Aasef G; Solomon, David

2017-06-01

Constant velocity rotations in darkness evoke vestibulo-ocular reflex in form of pre- and post-rotational nystagmus under cerebellar supervision. Reorientation of the head with respect to gravity, stimulating otolith and semicircular canal, during post-rotational phase rapidly suppresses the post-rotational nystagmus. We asked if pure otolith stimulation without semicircular canal signal is sufficient for the suppression of post-rotational nystagmus. The experimental paradigm comprised of on-axis rotations in the horizontal plane when the subject was sitting upright, followed by a novel stimulus that combined off-axis centrifugation in the horizontal plane with amplitude matched, yet out-of-phase, on-axis horizontal rotation-double centrifugation. The resultant effect of double centrifugation was pure otolith stimulation that constantly changed direction, yet completely canceled out angular velocity (no horizontal semicircular canal stimulation). Double centrifugation without pre-existing on-axis rotations evoked mixture of horizontal and vertical eye movements, latter reflected the known uncertainty of the vestibular system to differentiate whether the sensory signal is related to low-frequency translations in horizontal plane or head tilts relative to the gravity. Double centrifugation during post-rotational phase suppressed the peak slow phase eye velocity of the post-rotational nystagmus, hence affecting the vestibular ocular reflex gain (eye velocity/head velocity) matrix. The decay time constant, however, was unchanged. Amount of suppression of the peak slow phase eye velocity of the post-rotational nystagmus during double centrifugation correlated with the peak vertical eye velocity evoked by the pure otolith stimuli in the absence of pre-existing on axis rotations. In post-rotational phase, the pure otolith signal affects vestibular ocular reflex gain matrix but does not affect the time constant.

Rotation of the Sacrum During Bellyboard Pelvic Radiotherapy

International Nuclear Information System (INIS)

Kasabasic, Mladen; Faj, Dario; Ivkovic, Ana; Jurkovic, Slaven; Belaj, Nenad

2010-01-01

Patients with cervical, uterine, and rectal carcinomas are usually treated in the prone position using the bellyboard positioning device. Specific and uncomfortable prone position gives rise to uncertainties in the daily set-up of patients during the treatment. During investigation of translational movements, rotational movements of the pelvis are observed and investigated. The film portal imaging is used to discover patient positioning errors during treatment. We defined the rotational set-up errors by angle deviations of the sacrum. Thirty-six patients were included in the study; 15 patients were followed during the whole treatment and 21 during the first 5 consecutive treatment days. The image acquisitions were completed in 84%. Systematic and random positioning errors were analyzed in 725 images. Approximately half of the patients had adjusted to the bellyboard in the first few fractions, with sacrum angles remaining the same for the rest of the treatment. The other half had drifts of the sacrum angle during the whole treatment. The rotation of the sacrum during treatment ranged up to 14 deg., causing the usual set-up verification and correction procedure to result in errors up to 15 mm. Rotational movements of the patient pelvis during bellyboard pelvis radiotherapy can introduce considerable patient position error.

The interactions between pain, pain-related fear of movement and productivity

DEFF Research Database (Denmark)

Sell, L; Lund, H L; Holtermann, A

2014-01-01

BACKGROUND: Employees with physically heavy work have an increased risk of musculoskeletal disorders leading to reduced work ability. AIMS: To investigate if a high level of musculoskeletal pain or pain-related fear of movement was associated with low productivity among employees with physically....... CONCLUSIONS: Despite the fact that musculoskeletal pain increases the risk of reduced work ability significantly, musculoskeletal pain and pain-related fear of movement were associated with low productivity only among employees with good work ability....... heavy work and differing work ability levels. METHODS: The study was conducted at a Danish production site and employees with physically heavy work in the production line were included in the study. Work ability was assessed with the Work Ability Index (WAI), pain-related fear of movement with the Tampa...

Rotating frames in special relativity

International Nuclear Information System (INIS)

Strauss, M.

1979-01-01

The transformation theory for rotating frames presented in a previous paper is generalized by replacing the usual condition r = R for ωR < c (invariance of radius) by r = Rg(βsub(R)) so that r is now defined for all values of R, 0 <= R <= infinity. This generalization does not affect the kinematic transformation bracetheta, T → bracethetasup(r), bracesup(r) and the result group structure required by the theoretical constraints previously established, provided the old parameter 'r' (=R) is now identified throughout with either r or R; for physical reasons it must be identified with R. The function g, which cannot be fixed by theoretical constraints, determines the degree of geometrical anisotropy in the rotating plane z = const. More specifically, since g enters the expression for the ratio C/D (circumference/diameter) its choice corresponds to the choice of a congruence definition for lengths in radial and tangential directions. While on this (purely geometrical) level g remains undetermined, it can be uniquely determined experimentally on the kinematic level, e.g. by observing in Σsup(ω) the motion of a free particle. Thus the supremacy of kinematics over geometry is explicated by a further instance. At the same time, special relativity theory (SRT) is shown to belong to the class of theories with theoretically unsolvable problems. (author)

Methodological considerations for the 3D measurement of the X-factor and lower trunk movement in golf.

Science.gov (United States)

Joyce, Christopher; Burnett, Angus; Ball, Kevin

2010-09-01

It is believed that increasing the X-factor (movement of the shoulders relative to the hips) during the golf swing can increase ball velocity at impact. Increasing the X-factor may also increase the risk of low back pain. The aim of this study was to provide recommendations for the three-dimensional (3D) measurement of the X-factor and lower trunk movement during the golf swing. This three-part validation study involved; (1) developing and validating models and related algorithms (2) comparing 3D data obtained during static positions representative of the golf swing to visual estimates and (3) comparing 3D data obtained during dynamic golf swings to images gained from high-speed video. Of particular interest were issues related to sequence dependency. After models and algorithms were validated, results from parts two and three of the study supported the conclusion that a lateral bending/flexion-extension/axial rotation (ZYX) order of rotation was deemed to be the most suitable Cardanic sequence to use in the assessment of the X-factor and lower trunk movement in the golf swing. The findings of this study have relevance for further research examining the X-factor its relationship to club head speed and lower trunk movement and low back pain in golf.

Cerebral Activations Related to Ballistic, Stepwise Interrupted and Gradually Modulated Movements in Parkinson Patients

Science.gov (United States)

Toxopeus, Carolien M.; Maurits, Natasha M.; Valsan, Gopal; Conway, Bernard A.; Leenders, Klaus L.; de Jong, Bauke M.

2012-01-01

Patients with Parkinson’s disease (PD) experience impaired initiation and inhibition of movements such as difficulty to start/stop walking. At single-joint level this is accompanied by reduced inhibition of antagonist muscle activity. While normal basal ganglia (BG) contributions to motor control include selecting appropriate muscles by inhibiting others, it is unclear how PD-related changes in BG function cause impaired movement initiation and inhibition at single-joint level. To further elucidate these changes we studied 4 right-hand movement tasks with fMRI, by dissociating activations related to abrupt movement initiation, inhibition and gradual movement modulation. Initiation and inhibition were inferred from ballistic and stepwise interrupted movement, respectively, while smooth wrist circumduction enabled the assessment of gradually modulated movement. Task-related activations were compared between PD patients (N = 12) and healthy subjects (N = 18). In healthy subjects, movement initiation was characterized by antero-ventral striatum, substantia nigra (SN) and premotor activations while inhibition was dominated by subthalamic nucleus (STN) and pallidal activations, in line with the known role of these areas in simple movement. Gradual movement mainly involved antero-dorsal putamen and pallidum. Compared to healthy subjects, patients showed reduced striatal/SN and increased pallidal activation for initiation, whereas for inhibition STN activation was reduced and striatal-thalamo-cortical activation increased. For gradual movement patients showed reduced pallidal and increased thalamo-cortical activation. We conclude that PD-related changes during movement initiation fit the (rather static) model of alterations in direct and indirect BG pathways. Reduced STN activation and regional cortical increased activation in PD during inhibition and gradual movement modulation are better explained by a dynamic model that also takes into account enhanced

Cerebral activations related to ballistic, stepwise interrupted and gradually modulated movements in Parkinson patients.

Directory of Open Access Journals (Sweden)

Carolien M Toxopeus

Full Text Available Patients with Parkinson's disease (PD experience impaired initiation and inhibition of movements such as difficulty to start/stop walking. At single-joint level this is accompanied by reduced inhibition of antagonist muscle activity. While normal basal ganglia (BG contributions to motor control include selecting appropriate muscles by inhibiting others, it is unclear how PD-related changes in BG function cause impaired movement initiation and inhibition at single-joint level. To further elucidate these changes we studied 4 right-hand movement tasks with fMRI, by dissociating activations related to abrupt movement initiation, inhibition and gradual movement modulation. Initiation and inhibition were inferred from ballistic and stepwise interrupted movement, respectively, while smooth wrist circumduction enabled the assessment of gradually modulated movement. Task-related activations were compared between PD patients (N = 12 and healthy subjects (N = 18. In healthy subjects, movement initiation was characterized by antero-ventral striatum, substantia nigra (SN and premotor activations while inhibition was dominated by subthalamic nucleus (STN and pallidal activations, in line with the known role of these areas in simple movement. Gradual movement mainly involved antero-dorsal putamen and pallidum. Compared to healthy subjects, patients showed reduced striatal/SN and increased pallidal activation for initiation, whereas for inhibition STN activation was reduced and striatal-thalamo-cortical activation increased. For gradual movement patients showed reduced pallidal and increased thalamo-cortical activation. We conclude that PD-related changes during movement initiation fit the (rather static model of alterations in direct and indirect BG pathways. Reduced STN activation and regional cortical increased activation in PD during inhibition and gradual movement modulation are better explained by a dynamic model that also takes into account

Generalization of stochastic visuomotor rotations.

Directory of Open Access Journals (Sweden)

Hugo L Fernandes

Full Text Available Generalization studies examine the influence of perturbations imposed on one movement onto other movements. The strength of generalization is traditionally interpreted as a reflection of the similarity of the underlying neural representations. Uncertainty fundamentally affects both sensory integration and learning and is at the heart of many theories of neural representation. However, little is known about how uncertainty, resulting from variability in the environment, affects generalization curves. Here we extend standard movement generalization experiments to ask how uncertainty affects the generalization of visuomotor rotations. We find that although uncertainty affects how fast subjects learn, the perturbation generalizes independently of uncertainty.

Friction, Free Axes of Rotation and Entropy

Directory of Open Access Journals (Sweden)

Alexander Kazachkov

2017-03-01

Full Text Available Friction forces acting on rotators may promote their alignment and therefore eliminate degrees of freedom in their movement. The alignment of rotators by friction force was shown by experiments performed with different spinners, demonstrating how friction generates negentropy in a system of rotators. A gas of rigid rotators influenced by friction force is considered. The orientational negentropy generated by a friction force was estimated with the Sackur-Tetrode equation. The minimal change in total entropy of a system of rotators, corresponding to their eventual alignment, decreases with temperature. The reported effect may be of primary importance for the phase equilibrium and motion of ubiquitous colloidal and granular systems.

The effect of orientation on prehension movement time

NARCIS (Netherlands)

van Bergen, E.; van Swieten, L.M.; Williams, J.H.G.; Mon-Williams, M.

2007-01-01

We explored the relationship between hand orientation and movement time. Three groups of participants (n = 8 per group) were asked to grasp an object rotated in one of the following planes: (1) coronal; (2) sagittal; (3) horizontal. In the coronal plane, the rotational requirements directly mapped

The effect of orientation on prehension movement time

NARCIS (Netherlands)

Van Bergen, Elsje; van Swieten, Lisa M.; Williams, Justin H G; Mon-Williams, Mark A.

We explored the relationship between hand orientation and movement time. Three groups of participants (n = 8 per group) were asked to grasp an object rotated in one of the following planes: (1) coronal; (2) sagittal; (3) horizontal. In the coronal plane, the rotational requirements directly mapped

The Age-Related Association of Movement in Irish Adolescent Youth

Directory of Open Access Journals (Sweden)

Diarmuid Lester

2017-10-01

Full Text Available (1 Background: Research has shown that post-primary Irish youth are insufficiently active and fail to reach a level of proficiency across basic movement skills. The purpose of the current research was to gather cross-sectional baseline data on Irish adolescent youth, specifically the prevalence of movement skills and patterns, in order to generate an overall perspective of movement within the first three years (Junior Certificate level of post-primary education. (2 Methods: Data were collected on adolescents (N = 181; mean age: 14.42 ± 0.98 years, attending two, mixed-gender schools. Data collection included 10 fundamental movement skills (FMS and the seven tests within the Functional Movement Screen (FMS™. The data set was analysed using the Statistical Package for Social Sciences (SPSS version 20.0 for Windows. (3 Results: Overall, levels of actual mastery within fundamental and functional movement were low. There were statistically significant age-related differences observed, with a progressive decline as age increased in both the object control (p = 0.002 FMS sub-domain, and the in-line lunge (p = 0.048 test of the FMS™. (4 Conclusion: In summary, we found emerging evidence that school year group is significantly associated with mastery of movement skills and patterns. Results from the current study suggest that developing a specifically tailored movement-oriented intervention would be a strategic step towards improving the low levels of adolescent fundamental and functional movement proficiency.

Adaptive Changes in the Perception of Fast and Slow Movement at Different Head Positions.

Science.gov (United States)

Panichi, Roberto; Occhigrossi, Chiara; Ferraresi, Aldo; Faralli, Mario; Lucertini, Marco; Pettorossi, Vito E

2017-05-01

This paper examines the subjective sense of orientation during asymmetric body rotations in normal subjects. Self-motion perception was investigated in 10 healthy individuals during asymmetric whole-body rotation with different head orientations. Both on-vertical axis and off-vertical axis rotations were employed. Subjects tracked a remembered earth-fixed visual target while rotating in the dark for four cycles of asymmetric rotation (two half-sinusoidal cycles of the same amplitude, but of different duration). The rotations induced a bias in the perception of velocity (more pronounced with fast than with slow motion). At the end of rotation, a marked target position error (TPE) was present. For the on-vertical axis rotations, the TPE was no different if the rotations were performed with a 30° nose-down, a 60° nose-up, or a 90° side-down head tilt. With off-vertical axis rotations, the simultaneous activation of the semicircular canals and otolithic receptors produced a significant increase of TPE for all head positions. This difference between on-vertical and off-vertical axis rotation was probably partly due to the vestibular transfer function and partly due to different adaptation to the speed of rotation. Such a phenomenon might be generated in different components of the vestibular system. The adaptive process enhancing the perception of dynamic movement around the vertical axis is not related to the specific semicircular canals that are activated; the addition of an otolithic component results in a significant increase of the TPE.Panichi R, Occhigrossi C, Ferraresi A, Faralli M, Lucertini M, Pettorossi VE. Adaptive changes in the perception of fast and slow movement at different head positions. Aerosp Med Hum Perform. 2017; 88(5):463-468.

Postoperative stability of 2-jaw surgery with clockwise rotation of the occlusal plane.

Science.gov (United States)

Bang, Sung-Moon; Kwon, Yong-Dae; Kim, Su-Jung; Lee, Baek-Soo; Choi, Byung-Joon; Ohe, Joo-Young; Suh, Joon-Ho

2012-03-01

The objective of this study was to investigate the skeletal stability after Le Fort I osteotomy with clockwise rotation and bilateral sagittal split osteotomy. The sample consisted of 31 young Korean patients who were treated with Le Fort I osteotomy with clockwise rotation and setback bilateral sagittal split osteotomy. The lateral cephalographs were obtained before surgery (T1), right after surgery (T2), and on an average of 6.23 months after the operation (T3). The horizontal and vertical relations of landmarks to the reference line and soft tissue changes were evaluated. During the T2 - T1 period, there was superior and anterior movement of the posterior part (PNS, UMD) and advancement and impaction of the anterior part (ANS, A point, UIE) of the maxilla. The mandible was moved superiorly and posteriorly. During the T3 - T2 period, maxillary segment showed counterclockwise rotational relapse. The posterior part was relatively stable especially in the vertical position and the anterior part moved in the posterior and superior directions. Mandibular landmarks showed forward relapse in the horizontal aspect and superior relapse in the vertical aspect. The posterior part (PNS and UMD) showed a significantly higher stability rate (>70%) in the vertical aspect and the anterior part of the maxilla (ANS, A point) demonstrated a significantly lower value (occlusal plane showed stable results especially in the maxillary posterior landmarks. The clockwise rotational movement can be beneficial to increase skeletal stability and facial aesthetics in Asians.

Two-phase strategy of neural control for planar reaching movements: II--relation to spatiotemporal characteristics of movement trajectory.

Science.gov (United States)

Rand, Miya K; Shimansky, Yury P

2013-09-01

In the companion paper utilizing a quantitative model of optimal motor coordination (Part I, Rand and Shimansky, in Exp Brain Res 225:55-73, 2013), we examined coordination between X and Y movement directions (XYC) during reaching movements performed under three prescribed speeds, two movement amplitudes, and two target sizes. The obtained results indicated that the central nervous system (CNS) utilizes a two-phase strategy, where the initial and the final phases correspond to lower and higher precision of information processing, respectively, for controlling goal-directed reach-type movements to optimize the total cost of task performance including the cost of neural computations. The present study investigates how two different well-known concepts used for describing movement performance relate to the concepts of optimal XYC and two-phase control strategy. First, it is examined to what extent XYC is equivalent to movement trajectory straightness. The data analysis results show that the variability, the movement trajectory's deviation from the straight line, increases with an increase in prescribed movement speed. In contrast, the dependence of XYC strength on movement speed is opposite (in total agreement with an assumption of task performance optimality), suggesting that XYC is a feature of much higher level of generality than trajectory straightness. Second, it is tested how well the ballistic and the corrective components described in the traditional concept of two-component model of movement performance match with the initial and the final phase of the two-phase control strategy, respectively. In fast reaching movements, the percentage of trials with secondary corrective submovement was smaller under larger-target shorter-distance conditions. In slower reaching movements, meaningful parsing was impossible due to massive fluctuations in the kinematic profile throughout the movement. Thus, the parsing points determined by the conventional submovement analysis

Universal relations for differentially rotating relativistic stars at the threshold to collapse

Science.gov (United States)

Bozzola, Gabriele; Stergioulas, Nikolaos; Bauswein, Andreas

2018-03-01

A binary neutron star merger produces a rapidly and differentially rotating compact remnant whose lifespan heavily affects the electromagnetic and gravitational emissions. Its stability depends on both the equation of state (EOS) and the rotation law and it is usually investigated through numerical simulations. Nevertheless, by means of a sufficient criterion for secular instability, equilibrium sequences can be used as a computational inexpensive way to estimate the onset of dynamical instability, which, in general, is close to the secular one. This method works well for uniform rotation and relies on the location of turning points: stellar models that are stationary points in a sequence of equilibrium solutions with constant rest mass or angular momentum. Here, we investigate differentially rotating models (using a large number of EOSs and different rotation laws) and find that several universal relations between properly scaled gravitational mass, rest mass and angular momentum of the turning-point models that are valid for uniform rotation are insensitive to the degree of differential rotation, to high accuracy.

Scaling relations for plasma production and acceleration of rotating plasma flows

International Nuclear Information System (INIS)

Ikehata, Takashi; Tanabe, Toshio; Mase, Hiroshi; Sekine, Ryusuke; Hasegawa, Kazuyuki.

1989-01-01

Scaling relations are investigated theoretically and experimentally of the plasma production and acceleration in the rotating plasma gun which has been developed as a new means of plasma centrifuge. Two operational modes: the gas-discharge mode for gaseous elements and the vacuum-discharge mode for solid elements are studied. Relations of the plasma density and velocities to the discharge current and the magnetic field are derived. The agreement between experiment and theory is quite well. It is found that fully-ionized rotating plasmas produced in the gas-discharge mode is most advantageous to realize efficient plasma centrifuge. (author)

NASA supporting studies for microgravity research on eye movements

Science.gov (United States)

Cohen, Bernard

1990-01-01

The purpose of the work on this project was to provide support for ground-based studies on the effects of gravity on eye movements. The effects of microgravity on the optokinetic eye movements of humans are investigated. OKN was induced by having subjects watch 3.3 deg stripes moving at 35 deg/s for 45 s in a binocular, head-fixed apparatus. The field (hor., 88 deg; vert., 72 deg), was rotated about axes that were upright or tilted 45 deg or 90 deg. The head was upright or tilted 45 deg on the body. Head-horizontal (yaw axis) and head-vertical (pitch axis) components of OKN were recorded with electro-oculography (EOG). Slow phase velocity vectors were determined relative to gravity. With the head upright, the axis of eye rotation during yaw axis OKN was coincident with the stimulus axis and the spatial vertical. With the head tilted 45 deg on the body, a persistent vertical component of eye velocity developed during yaw axis stimulation, and there was an average shift of the axis of eye rotation toward the spatial vertical of approximately 18 deg in six subjects. During oblique optokinetic stimulation with the head upright, the axis of eye rotation shifted 12 deg toward the spatial vertical. When the head was tilted, the axis of eye rotation rotated to the other side of the spatial vertical by 5.4 deg during the same oblique stimulation. This counter-rotation of the axis of eye rotation is similar to the 'Muller (E) effect', in which the perception of the upright counter-rotates to the opposite side of the spatial vertical when subjects are tilted in darkness. The data were simulated by a model of OKN. Despite the short OKAN time constants, strong horizontal to vertical cross-coupling was produced if the horizontal and vertical time constants were in proper ratio, and there was no suppression of nystagmus orthogonal to the stimulus direction. This shows that the spatial orientation of OKN can be due to a restructuring of the system matrix of velocity storage as a

Relative sensitivity of depth discrimination for ankle inversion and plantar flexion movements.

Science.gov (United States)

Black, Georgia; Waddington, Gordon; Adams, Roger

2014-02-01

25 participants (20 women, 5 men) were tested for sensitivity in discrimination between sets of six movements centered on 8 degrees, 11 degrees, and 14 degrees, and separated by 0.3 degrees. Both inversion and plantar flexion movements were tested. Discrimination of the extent of inversion movement was observed to decline linearly with increasing depth; however, for plantar flexion, the discrimination function for movement extent was found to be non-linear. The relatively better discrimination of plantar flexion movements than inversion movements at around 11 degrees from horizontal is interpreted as an effect arising from differential amounts of practice through use, because this position is associated with the plantar flexion movement made in normal walking. The fact that plantar flexion movements are discriminated better than inversion at one region but not others argues against accounts of superior proprioceptive sensitivity for plantar flexion compared to inversion that are based on general properties of plantar flexion such as the number of muscle fibres on stretch.

The dynamic behavior of bacterial macrofibers growing with one end prevented from rotating: variation in shaft rotation along the fiber's length, and supercoil movement on a solid surface toward the constrained end

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Chen Liling

2003-08-01

Full Text Available Abstract Background Bacterial macrofibers twist as they grow, writhe, supercoil and wind up into plectonemic structures (helical forms the individual filaments of which cannot be taken apart without unwinding that eventually carry loops at both of their ends. Terminal loops rotate about the axis of a fiber's shaft in contrary directions at increasing rate as the shaft elongates. Theory suggests that rotation rates should vary linearly along the length of a fiber ranging from maxima at the loop ends to zero at an intermediate point. Blocking rotation at one end of a fiber should lead to a single gradient: zero at the blocked end to maximum at the free end. We tested this conclusion by measuring directly the rotation at various distances along fiber length from the blocked end. The movement of supercoils over a solid surface was also measured in tethered macrofibers. Results Macrofibers that hung down from a floating wire inserted through a terminal loop grew vertically and produced small plectonemic structures by supercoiling along their length. Using these as markers for shaft rotation we observed a uniform gradient of initial rotation rates with slopes of 25.6°/min. mm. and 36.2°/min. mm. in two different fibers. Measurements of the distal tip rotation in a third fiber as a function of length showed increases proportional to increases in length with constant of proportionality 79.2 rad/mm. Another fiber tethered to the floor grew horizontally with a length-doubling time of 74 min, made contact periodically with the floor and supercoiled repeatedly. The supercoils moved over the floor toward the tether at approximately 0.06 mm/min, 4 times faster than the fiber growth rate. Over a period of 800 minutes the fiber grew to 23 mm in length and was entirely retracted back to the tether by a process involving 29 supercoils. Conclusions The rate at which growing bacterial macrofibers rotated about the axis of the fiber shaft measured at various

The punctum fixum-punctum mobile model: a neuromuscular principle for efficient movement generation?

Science.gov (United States)

von Laßberg, Christoph; Rapp, Walter

2015-01-01

According to the "punctum fixum-punctum mobile model" that was introduced in prior studies, for generation of the most effective intentional acceleration of a body part the intersegmental neuromuscular onset succession has to spread successively from the rotation axis (punctum fixum) toward the body part that shall be accelerated (punctum mobile). The aim of the present study was to investigate whether this principle is, indeed, fundamental for any kind of efficient rotational accelerations in general, independent of the kind of movements, type of rotational axis, the current body position, or movement direction. Neuromuscular onset succession was captured by surface electromyography of relevant muscles of the anterior and posterior muscle chain in 16 high-level gymnasts during intentional accelerating movement phases while performing 18 different gymnastics elements (in various body positions to forward and backward, performed on high bar, parallel bars, rings and trampoline), as well as during non-sport specific pivot movements around the longitudinal axis. The succession patterns to generate the acceleration phases during these movements were described and statistically evaluated based on the onset time difference between the muscles of the corresponding muscle chain. In all the analyzed movement phases, the results clearly support the hypothesized succession pattern from punctum fixum to punctum mobile. This principle was further underlined by the finding that the succession patterns do change their direction running through the body when the rotational axis (punctum fixum) has been changed (e.g., high bar or rings [hands] vs. floor or trampoline [feet]). The findings improve our understanding of intersegmental neuromuscular coordination patterns to generate intentional movements most efficiently. This could help to develop more specific methods to facilitate such patterns in particular contexts, thus allowing for shorter motor learning procedures of context

The punctum fixum-punctum mobile model: a neuromuscular principle for efficient movement generation?

Directory of Open Access Journals (Sweden)

Christoph von Laßberg

Full Text Available According to the "punctum fixum-punctum mobile model" that was introduced in prior studies, for generation of the most effective intentional acceleration of a body part the intersegmental neuromuscular onset succession has to spread successively from the rotation axis (punctum fixum toward the body part that shall be accelerated (punctum mobile. The aim of the present study was to investigate whether this principle is, indeed, fundamental for any kind of efficient rotational accelerations in general, independent of the kind of movements, type of rotational axis, the current body position, or movement direction. Neuromuscular onset succession was captured by surface electromyography of relevant muscles of the anterior and posterior muscle chain in 16 high-level gymnasts during intentional accelerating movement phases while performing 18 different gymnastics elements (in various body positions to forward and backward, performed on high bar, parallel bars, rings and trampoline, as well as during non-sport specific pivot movements around the longitudinal axis. The succession patterns to generate the acceleration phases during these movements were described and statistically evaluated based on the onset time difference between the muscles of the corresponding muscle chain. In all the analyzed movement phases, the results clearly support the hypothesized succession pattern from punctum fixum to punctum mobile. This principle was further underlined by the finding that the succession patterns do change their direction running through the body when the rotational axis (punctum fixum has been changed (e.g., high bar or rings [hands] vs. floor or trampoline [feet]. The findings improve our understanding of intersegmental neuromuscular coordination patterns to generate intentional movements most efficiently. This could help to develop more specific methods to facilitate such patterns in particular contexts, thus allowing for shorter motor learning

The Punctum Fixum-Punctum Mobile Model: A Neuromuscular Principle for Efficient Movement Generation?

Science.gov (United States)

von Laßberg, Christoph; Rapp, Walter

2015-01-01

According to the “punctum fixum–punctum mobile model” that was introduced in prior studies, for generation of the most effective intentional acceleration of a body part the intersegmental neuromuscular onset succession has to spread successively from the rotation axis (punctum fixum) toward the body part that shall be accelerated (punctum mobile). The aim of the present study was to investigate whether this principle is, indeed, fundamental for any kind of efficient rotational accelerations in general, independent of the kind of movements, type of rotational axis, the current body position, or movement direction. Neuromuscular onset succession was captured by surface electromyography of relevant muscles of the anterior and posterior muscle chain in 16 high-level gymnasts during intentional accelerating movement phases while performing 18 different gymnastics elements (in various body positions to forward and backward, performed on high bar, parallel bars, rings and trampoline), as well as during non-sport specific pivot movements around the longitudinal axis. The succession patterns to generate the acceleration phases during these movements were described and statistically evaluated based on the onset time difference between the muscles of the corresponding muscle chain. In all the analyzed movement phases, the results clearly support the hypothesized succession pattern from punctum fixum to punctum mobile. This principle was further underlined by the finding that the succession patterns do change their direction running through the body when the rotational axis (punctum fixum) has been changed (e.g., high bar or rings [hands] vs. floor or trampoline [feet]). The findings improve our understanding of intersegmental neuromuscular coordination patterns to generate intentional movements most efficiently. This could help to develop more specific methods to facilitate such patterns in particular contexts, thus allowing for shorter motor learning procedures of

A comparison between flexible electrogoniometers, inclinometers and three-dimensional video analysis system for recording neck movement.

Science.gov (United States)

Carnaz, Letícia; Moriguchi, Cristiane S; de Oliveira, Ana Beatriz; Santiago, Paulo R P; Caurin, Glauco A P; Hansson, Gert-Åke; Coury, Helenice J C Gil

2013-11-01

This study compared neck range of movement recording using three different methods goniometers (EGM), inclinometers (INC) and a three-dimensional video analysis system (IMG) in simultaneous and synchronized data collection. Twelve females performed neck flexion-extension, lateral flexion, rotation and circumduction. The differences between EGM, INC, and IMG were calculated sample by sample. For flexion-extension movement, IMG underestimated the amplitude by 13%; moreover, EGM showed a crosstalk of about 20% for lateral flexion and rotation axes. In lateral flexion movement, all systems showed similar amplitude and the inter-system differences were moderate (4-7%). For rotation movement, EGM showed a high crosstalk (13%) for flexion-extension axis. During the circumduction movement, IMG underestimated the amplitude of flexion-extension movements by about 11%, and the inter-system differences were high (about 17%) except for INC-IMG regarding lateral flexion (7%) and EGM-INC regarding flexion-extension (10%). For application in workplace, INC presents good results compared to IMG and EGM though INC cannot record rotation. EGM should be improved in order to reduce its crosstalk errors and allow recording of the full neck range of movement. Due to non-optimal positioning of the cameras for recording flexion-extension, IMG underestimated the amplitude of these movements. Copyright © 2013 IPEM. Published by Elsevier Ltd. All rights reserved.

Rapidly rotating neutron stars with a massive scalar field—structure and universal relations

International Nuclear Information System (INIS)

Doneva, Daniela D.; Yazadjiev, Stoytcho S.

2016-01-01

We construct rapidly rotating neutron star models in scalar-tensor theories with a massive scalar field. The fact that the scalar field has nonzero mass leads to very interesting results since the allowed range of values of the coupling parameters is significantly broadened. Deviations from pure general relativity can be very large for values of the parameters that are in agreement with the observations. We found that the rapid rotation can magnify the differences several times compared to the static case. The universal relations between the normalized moment of inertia and quadrupole moment are also investigated both for the slowly and rapidly rotating cases. The results show that these relations are still EOS independent up to a large extend and the deviations from pure general relativity can be large. This places the massive scalar-tensor theories amongst the few alternative theories of gravity that can be tested via the universal I -Love- Q relations.

Rapidly rotating neutron stars with a massive scalar field—structure and universal relations

Energy Technology Data Exchange (ETDEWEB)

Doneva, Daniela D.; Yazadjiev, Stoytcho S., E-mail: daniela.doneva@uni-tuebingen.de, E-mail: yazad@phys.uni-sofia.bg [Theoretical Astrophysics, Eberhard Karls University of Tübingen, Tübingen 72076 (Germany)

2016-11-01

We construct rapidly rotating neutron star models in scalar-tensor theories with a massive scalar field. The fact that the scalar field has nonzero mass leads to very interesting results since the allowed range of values of the coupling parameters is significantly broadened. Deviations from pure general relativity can be very large for values of the parameters that are in agreement with the observations. We found that the rapid rotation can magnify the differences several times compared to the static case. The universal relations between the normalized moment of inertia and quadrupole moment are also investigated both for the slowly and rapidly rotating cases. The results show that these relations are still EOS independent up to a large extend and the deviations from pure general relativity can be large. This places the massive scalar-tensor theories amongst the few alternative theories of gravity that can be tested via the universal I -Love- Q relations.

Relative Attitude Estimation for a Uniform Motion and Slowly Rotating Noncooperative Spacecraft

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Liu Zhang

2017-01-01

Full Text Available This paper presents a novel relative attitude estimation approach for a uniform motion and slowly rotating noncooperative spacecraft. It is assumed that the uniform motion and slowly rotating noncooperative chief spacecraft is in failure or out of control and there is no a priori rotation rate information. We utilize a very fast binary descriptor based on binary robust independent elementary features (BRIEF to obtain the features of the target, which are rotational invariance and resistance to noise. And then, we propose a novel combination of single candidate random sample consensus (RANSAC with extended Kalman filter (EKF that makes use of the available prior probabilistic information from the EKF in the RANSAC model hypothesis stage. The advantage of this combination obviously reduces the sample size to only one, which results in large computational savings without the loss of accuracy. Experimental results from real image sequence of a real model target show that the relative angular error is about 3.5% and the mean angular velocity error is about 0.1 deg/s.

Age-related cutoffs for cervical movement behaviour to distinguish chronic idiopathic neck pain patients from unimpaired subjects.

Science.gov (United States)

Niederer, Daniel; Vogt, Lutz; Wilke, Jan; Rickert, Marcus; Banzer, Winfried

2015-03-01

The present study aims to develop age-dependent cutoff values in a quasi-experimental, cross-sectional diagnostic test study. One hundred and twenty (120) asymptomatic subjects (n = 100, 36♀, 18 75 years, for normative values; n = 20, 23-75 years, 15♀, for selectivity analyses) and 20 patients suffering from idiopathic neck pain (selectivity analyses, 22-71 years, 15♀) were included. Subjects performed five repetitive maximal cervical flexion/extension movements in an upright sitting position. Cervical kinematic characteristics (maximal range of motion (ROM), coefficient of variation (CV) and mean conjunct movements in rotation and flexion (CM)) were calculated from raw 3D ultrasonic data. Regression analyses were conducted to reveal associations between kinematic characteristics and age and gender and thus to determine normative values for healthy subjects. Age explains 53 % of the variance in ROM (decrease 10.2° per decade), 13 % in CV (increase 0.003 per decade) and 9 % in CM (increase 0.57° per decade). Receivers operating characteristic (ROC) analyses were conducted for differences between individual values of the kinematic characteristics and normative values to optimise cutoff values for distinguishing patients from unimpaired subjects (20 patients and 20 healthy). Cutoff values distinguished asymptomatic subjects' and chronic nonspecific neck patient's movement characteristics with sufficient quality (sensitivity 70-80 %, specificity 65-70 %). By including such classifications, the present findings expand actual research stating an age-related decrease in kinematic behaviour only using categorising span widths across decades. Future study is warranted to reveal our results' potential applicability for intervention onset decision making for idiopathic neck pain patients.

Case Report of Acute Traumatic Rotator Cuff Tear Treatment in Traditional Korean Medicine

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Jeong-Hwan Lee

2011-12-01

Full Text Available Objectives: There is no report on treatment of acute traumatic rotator cuff tear in Traditional Korean Medicine. We reported Traditional Korean Treatment for pain relief and better movement of acute traumatic rotator cuff tear. Methods: Shoulder MRI was used to confirm the diagnosis of tear of rotator cuff. The patient was treated with Traditional Korean Methods (Acupuncture, Herbal medicine, Pharmacopuncture for 6 months. We evaluated the patient through VAS (Visual Analogue Scale, UCLA shoulder scale, ROM (Range of motion and Shoulder MRI. Results: After 6 months of treatment, the patient's VAS was decreased whereas UCLA score and Shoulder ROM were increased. Rotator cuff tear was repaired on Shoulder MRI images. Conclusions: In acute traumatic rotator cuff tear, Korean Traditional Treatment is good method for pain relief and better movement.

Movement coordination patterns between the foot joints during walking

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John B. Arnold

2017-10-01

Full Text Available Abstract Background In 3D gait analysis, kinematics of the foot joints are usually reported via isolated time histories of joint rotations and no information is provided on the relationship between rotations at different joints. The aim of this study was to identify movement coordination patterns in the foot during walking by expanding an existing vector coding technique according to an established multi-segment foot and ankle model. A graphical representation is also described to summarise the coordination patterns of joint rotations across multiple patients. Methods Three-dimensional multi-segment foot kinematics were recorded in 13 adults during walking. A modified vector coding technique was used to identify coordination patterns between foot joints involving calcaneus, midfoot, metatarsus and hallux segments. According to the type and direction of joints rotations, these were classified as in-phase (same direction, anti-phase (opposite directions, proximal or distal joint dominant. Results In early stance, 51 to 75% of walking trials showed proximal-phase coordination between foot joints comprising the calcaneus, midfoot and metatarsus. In-phase coordination was more prominent in late stance, reflecting synergy in the simultaneous inversion occurring at multiple foot joints. Conversely, a distal-phase coordination pattern was identified for sagittal plane motion of the ankle relative to the midtarsal joint, highlighting the critical role of arch shortening to locomotor function in push-off. Conclusions This study has identified coordination patterns between movement of the calcaneus, midfoot, metatarsus and hallux by expanding an existing vector cording technique for assessing and classifying coordination patterns of foot joints rotations during walking. This approach provides a different perspective in the analysis of multi-segment foot kinematics, and may be used for the objective quantification of the alterations in foot joint

Influences of rhythm- and timbre-related musical features on characteristics of music-induced movement.

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Burger, Birgitta; Thompson, Marc R; Luck, Geoff; Saarikallio, Suvi; Toiviainen, Petri

2013-01-01

Music makes us move. Several factors can affect the characteristics of such movements, including individual factors or musical features. For this study, we investigated the effect of rhythm- and timbre-related musical features as well as tempo on movement characteristics. Sixty participants were presented with 30 musical stimuli representing different styles of popular music, and instructed to move along with the music. Optical motion capture was used to record participants' movements. Subsequently, eight movement features and four rhythm- and timbre-related musical features were computationally extracted from the data, while the tempo was assessed in a perceptual experiment. A subsequent correlational analysis revealed that, for instance, clear pulses seemed to be embodied with the whole body, i.e., by using various movement types of different body parts, whereas spectral flux and percussiveness were found to be more distinctly related to certain body parts, such as head and hand movement. A series of ANOVAs with the stimuli being divided into three groups of five stimuli each based on the tempo revealed no significant differences between the groups, suggesting that the tempo of our stimuli set failed to have an effect on the movement features. In general, the results can be linked to the framework of embodied music cognition, as they show that body movements are used to reflect, imitate, and predict musical characteristics.

Influences of rhythm- and timbre-related musical features on characteristics of music-induced movement

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Birgitta eBurger

2013-04-01

Full Text Available Music makes us move. Several factors can affect the characteristics of such movements, including individual factors or musical features. For this study, we investigated the effect of rhythm- and timbre-related musical features as well as tempo on movement characteristics. Sixty participants were presented with 30 musical stimuli representing different styles of popular music, and instructed to move along with the music. Optical motion capture was used to record participants’ movements. Subsequently, eight movement features and four rhythm- and timbre-related musical features were computationally extracted from the data, while the tempo was assessed in a perceptual experiment. A subsequent correlational analysis revealed that, for instance, clear pulses seemed to be embodied with the whole body, i.e., by using various movement types of different body parts, whereas spectral flux and percussiveness were found to be more distinctly related to certain body parts, such as head and hand movement. A series of ANOVAs with the stimuli being divided into three groups of five stimuli each based on the tempo revealed no significant differences between the groups, suggesting that the tempo of our stimuli set failed to have an effect on the movement features. In general, the results can be linked to the framework of embodied music cognition, as they show that body movements are used to reflect, imitate, and predict musical characteristics.

Mental rotation and working memory in musicians' dystonia.

Science.gov (United States)

Erro, Roberto; Hirschbichler, Stephanie T; Ricciardi, Lucia; Ryterska, Agata; Antelmi, Elena; Ganos, Christos; Cordivari, Carla; Tinazzi, Michele; Edwards, Mark J; Bhatia, Kailash P

2016-11-01

Mental rotation of body parts engages cortical-subcortical areas that are actually involved in the execution of a movement. Musicians' dystonia is a type of focal hand dystonia that is grouped together with writer's cramp under the rubric of "occupational dystonia", but it is unclear to which extent these two disorders share common pathophysiological mechanisms. Previous research has demonstrated patients with writer's cramp to have deficits in mental rotation of body parts. It is unknown whether patients with musicians' dystonia would display similar deficits, reinforcing the concept of shared pathophysiology. Eight patients with musicians' dystonia and eight healthy musicians matched for age, gender and musical education, performed a number of tasks assessing mental rotation of body parts and objects as well as verbal and spatial working memories abilities. There were no differences between patients and healthy musicians as to accuracy and reaction times in any of the tasks. Patients with musicians' dystonia have intact abilities in mentally rotating body parts, suggesting that this disorder relies on a highly selective disruption of movement planning and execution that manifests only upon playing a specific instrument. We further demonstrated that mental rotation of body parts and objects engages, at least partially, different cognitive networks. Copyright © 2016 Elsevier Inc. All rights reserved.

Numerical comparisons of the performance of a hydraulic coupling with different pump rotational speeds

International Nuclear Information System (INIS)

Luo, Y; Feng, L H; Liu, S H; Chen, T J; Fan, H G

2013-01-01

A hydraulic coupling is a hydrodynamic device for transmitting rotating mechanical power. It is widely used in the machinery industry because of its advantages of high energy transmission efficiency, shock absorption and good adaptability, etc. In this paper, SIMPLEC algorithm and SST k-ω turbulence model were employed to simulate the steady state flows at operating conditions of two different rotational speeds (3000r/min and 7500 r/min) of the pump of a specified hydraulic coupling model. The results indicate the existence of similarity in the distributions of the flow fields between the two speeds, but the efficiency at the optimum condition is larger with higher rotational speed. It is concluded that the similarity principle of the efficiency of the hydraulic couplings does not apply in this case due to the relatively high rotating speed and small geometric specifications. It is also shown that the radially stratified pressure distribution on the torus section becomes more obvious with larger speed ratios, since the centrifugal movement plays more dominant roles over the circulating movement in these situations. When the speed ratio is small, with the completion of the circulating flow, the pressure distribution presents in a more circular pattern around the neutral zone of the torus section

Imaging movement-related activity in medicated Parkin-associated and sporadic Parkinson's disease

DEFF Research Database (Denmark)

van Eimeren, Thilo; Binkofski, Ferdinand; Buhmann, Carsten

2010-01-01

Treatment-related motor complications such as dyskinesias are a major problem in the long-term management of Parkinson's disease (PD). In sporadic PD, a relatively early onset of the disease is known to be associated with an early development of dyskinesias. Although linked with early onset...... selected movements. Patients with Parkin-associated and sporadic PD showed no difference in movement-related activation patterns. Moreover, the covariates 'age' and 'disease duration' similarly influenced brain activation in both patient groups. The present finding suggests that a stable long-term motor...

Coordinated Control of Three-Dimensional Components of Smooth Pursuit to Rotating and Translating Textures.

Science.gov (United States)

Edinger, Janick; Pai, Dinesh K; Spering, Miriam

2017-01-01

The neural control of pursuit eye movements to visual textures that simultaneously translate and rotate has largely been neglected. Here we propose that pursuit of such targets-texture pursuit-is a fully three-dimensional task that utilizes all three degrees of freedom of the eye, including torsion. Head-fixed healthy human adults (n = 8) tracked a translating and rotating random dot pattern, shown on a computer monitor, with their eyes. Horizontal, vertical, and torsional eye positions were recorded with a head-mounted eye tracker. The torsional component of pursuit is a function of the rotation of the texture, aligned with its visual properties. We observed distinct behaviors between those trials in which stimulus rotation was in the same direction as that of a rolling ball ("natural") in comparison to those with the opposite rotation ("unnatural"): Natural rotation enhanced and unnatural rotation reversed torsional velocity during pursuit, as compared to torsion triggered by a nonrotating random dot pattern. Natural rotation also triggered pursuit with a higher horizontal velocity gain and fewer and smaller corrective saccades. Furthermore, we show that horizontal corrective saccades are synchronized with torsional corrective saccades, indicating temporal coupling of horizontal and torsional saccade control. Pursuit eye movements have a torsional component that depends on the visual stimulus. Horizontal and torsional eye movements are separated in the motor periphery. Our findings suggest that translational and rotational motion signals might be coordinated in descending pursuit pathways.

Movimentos oculares e padrões de busca visual em tarefas de rotação mental Eye movements and scan patterns in mental rotation tasks

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Priscila Covre

2005-06-01

Full Text Available O objetivo deste estudo é identificar as estratégias utilizadas nas tarefas de rotação mental pela análise dos traçados dos movimentos oculares. Foi analisado o desempenho de 40 participantes na comparação de pares de objetos tridimensionais rotacionados no eixo y, com diferenças de angulação de 0o a 180o. Foi utilizado um sistema computacional de rastreamento dos movimentos oculares (eyetracking durante a visualização de figuras. Os resultados mostram que tempo de julgamento, duração média das fixações do olho, número de fixações nos objetos e número de alternâncias entre os dois objetos aumentam em função da diferença de angulação. Análise dos traçados oculares, com base na inspeção visual, indica o uso de dois tipos de estratégias: rotação mental em torno dos eixos padrões e comparação independente da orientação. O uso dessas estratégias é discutido com relação ao desempenho dos participantes e à memória de trabalho.The purpose of this paper is to identify the strategies used on mental rotation tasks by analyzing ocular movements. The performance of 40 participants on comparison of pairs of three-dimensional objects, rotated on the y-axis, from 0o to 180o was analyzed. An eye-tracking computerized system was used to track eye movements during scene visualization. Results showed that judgment time, fixation duration, number of fixations and number of switches between the objects increased with rotation angle. Analysis by visual inspection indicates the use of two kinds of strategies: Mental rotation around the standard axis and comparison of orientation-free descriptions. The use of the strategies is discussed with regard to performance and working memory.

Evaluation of muscular activity duration in shoulders with rotator cuff tears using inertial sensors and electromyography

International Nuclear Information System (INIS)

Duc, Cyntia; Aminian, Kamiar; Pichonnaz, Claude; Farron, Alain; Jolles, Brigitte M; Bassin, Jean-Philippe

2014-01-01

Shoulder disorders, including rotator cuff tears, affect the shoulder function and result in adapted muscle activation. Although these adaptations have been studied in controlled conditions, free-living activities have not been investigated. Based on the kinematics measured with inertial sensors and portable electromyography, the objectives of this study were to quantify the duration of the muscular activation in the upper trapezius (UT), medial deltoid (MD) and biceps brachii (BB) during motion and to investigate the effect of rotator cuff tear in laboratory settings and daily conditions. The duration of movements and muscular activations were analysed separately and together using the relative time of activation (T EMG/mov ). Laboratory measurements showed the parameter’s reliability through movement repetitions (ICC > 0.74) and differences in painful shoulders compared with healthy ones (p < 0.05): longer activation for UT; longer activation for MD during abduction and tendency to shorter activation in other movements; shorter activation for BB. In daily conditions, T EMG/mov for UT was longer, whereas it was shorter for MD and BB (p < 0.05). Moreover, significant correlations were observed between these parameters and clinical scores. This study thus provides new insights into the rotator cuff tear effect on duration of muscular activation in daily activity. (paper)

Tully-Fisher relation, galactic rotation curves and dissipative mirror dark matter

Energy Technology Data Exchange (ETDEWEB)

Foot, R., E-mail: rfoot@unimelb.edu.au [ARC Centre of Excellence for Particle Physics at the Terascale, School of Physics, University of Melbourne, Victoria 3010 Australia (Australia)

2014-12-01

If dark matter is dissipative then the distribution of dark matter within galactic halos can be governed by dissipation, heating and hydrostatic equilibrium. Previous work has shown that a specific model, in the framework of mirror dark matter, can explain several empirical galactic scaling relations. It is shown here that this dynamical halo model implies a quasi-isothermal dark matter density, ρ(r) ≅ ρ{sub 0}r{sub 0}{sup 2}/(r{sup 2}+r{sub 0}{sup 2}), where the core radius, r{sub 0}, scales with disk scale length, r{sub D}, via r{sub 0}/kpc ≈ 1.4(r{sub D}/kpc). Additionally, the product ρ{sub 0}r{sub 0} is roughly constant, i.e. independent of galaxy size (the constant is set by the parameters of the model). The derived dark matter density profile implies that the galactic rotation velocity satisfies the Tully-Fisher relation, L{sub B}∝v{sup 3}{sub max}, where v{sub max} is the maximal rotational velocity. Examples of rotation curves resulting from this dynamics are given.

How to test the special theory of relativity on rotating earth

International Nuclear Information System (INIS)

Abolghasem, H.; Khadjehpoor, M.R.; Mansouri, R.

1988-02-01

In the framework of a one parameter test theory of special relativity, the difference between Transport- and Einstein synchronization on the rotating earth is calculated. For the special theory of relativity this difference vanishes. Therefore, experiments in which these synchronization procedures are compared, test the special theory of relativity. (author). 8 refs

Calibrated Tully-Fisher relations for improved estimates of disc rotation velocities

NARCIS (Netherlands)

Reyes, R.; Mandelbaum, R.; Gunn, J. E.; Pizagno II, Jim; Lackner, C. N.

2011-01-01

In this paper, we derive scaling relations between photometric observable quantities and disc galaxy rotation velocity V-rot or Tully-Fisher relations (TFRs). Our methodology is dictated by our purpose of obtaining purely photometric, minimal-scatter estimators of V-rot applicable to large galaxy

Observations and Measurements of Wing Parameters of the Selected Beetle Species and the Design of a Mechanism Structure Implementing a Complex Wing Movement

Directory of Open Access Journals (Sweden)

Geisler T.

2016-12-01

Full Text Available Beetle wings perform a flapping movement, consisting of the rotation relative to the two axes. This paper presents the results of observations and measurements of wings operating parameters in different planes of some beetle species. High speed photos and videos were used. The concept of the mechanism performing a complex wing movement was proposed and developed.

Observations and Measurements of Wing Parameters of the Selected Beetle Species and the Design of a Mechanism Structure Implementing a Complex Wing Movement

Science.gov (United States)

Geisler, T.

2016-12-01

Beetle wings perform a flapping movement, consisting of the rotation relative to the two axes. This paper presents the results of observations and measurements of wings operating parameters in different planes of some beetle species. High speed photos and videos were used. The concept of the mechanism performing a complex wing movement was proposed and developed.

Designing safer composite helmets to reduce rotational accelerations during oblique impacts.

Science.gov (United States)

Mosleh, Yasmine; Cajka, Martin; Depreitere, Bart; Vander Sloten, Jos; Ivens, Jan

2018-05-01

Oblique impact is the most common accident situation that occupants in traffic accidents or athletes in professional sports experience. During oblique impact, the human head is subjected to a combination of linear and rotational accelerations. Rotational movement is known to be responsible for traumatic brain injuries. In this article, composite foam with a column/matrix composite configuration is proposed for head protection applications to replace single-layer uniform foam, to better attenuate rotational movement of the head during oblique impacts. The ability of composite foam in the mitigation of rotational head movement is studied by performing finite element (FE) simulations of oblique impact on flat and helmet shape specimens. The performance of composite foam with respect to parameters such as compliance of the matrix foam and the number, size and cross-sectional shape of the foam columns is explored in detail, and subsequently an optimized structure is proposed. The simulation results show that using composite foam instead of single-layer foam, the rotational acceleration and velocity of the headform can be significantly reduced. The parametric study indicates that using a more compliant matrix foam and by increasing the number of columns in the composite foam configuration, the rotation can be further mitigated. This was confirmed by experimental results. The simulation results were also analyzed based on global head injury criteria such as head injury criterion, rotational injury criterion, brain injury criterion and generalized acceleration model for brain injury threshold which further confirmed the superior performance of composite foam versus single-layer homogeneous expanded polystyrene foam. The findings of simulations give invaluable information for design of protective helmets or, for instance, headliners for the automotive industry.

Measurements of Drag Coefficients and Rotation Rates of Free-Falling Helixes

KAUST Repository

Al-Omari, Abdulrhaman A.

2016-01-01

in water, glycerol and a mixture of 30% glycerol in water. That generated rotation due to helical angle in water. However, we observe the rotation disappear in glycerol. The movement of the solid helical shapes is imaged using a high-speed video camera

Composite body movements modulate numerical cognition: Evidence from the motion–numerical compatibility effect

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Xiaorong eCheng

2015-11-01

Full Text Available A recent hierarchical model of numerical processing, initiated by Fischer and Brugger (2011 and Fisher (2012, suggested that situated factors, such as different body postures and body movements, can influence the magnitude representation and bias numerical processing. Indeed, Loetscher and colleagues (2008 found that participants’ behavior in a random number generation (RNG task was biased by head rotations. More small numbers were reported after leftward than rightward head turns, i.e. a motion–numerical compatibility effect. Here, by carrying out two experiments, we explored whether similar motion–numerical compatibility effects exist for movements of other important body components, e.g. arms, and for composite body movements as well, which are basis for complex human activities in many ecologically meaningful situations. In Experiment 1, a motion-numerical compatibility effect was observed for lateral rotations of two body components, i.e., the head and arms. Relatively large numbers were reported after making rightward compared to leftward movements for both lateral head and arm turns. The motion-numerical compatibility effect was observed again in Experiment 2 when participants were asked to perform composite body movements of congruent movement directions, e.g., simultaneous head left turns and arm left turns. However, it disappeared when the movement directions were incongruent, e.g., simultaneous head left turns and arm right turns. Taken together, our results extended Loetscher et al.'s (2008 finding by demonstrating that their effect is effector-general and exists for arm movements. Moreover, our study reveals for the first time that the impact of spatial information on numerical processing induced by each of the two sensorimotor-based situated factors, e.g., a lateral head turn and a lateral arm turn, can cancel each other out.

Three-hair relations for rotating stars: Nonrelativistic limit

Energy Technology Data Exchange (ETDEWEB)

Stein, Leo C. [Center for Radiophysics and Space Research, Cornell University, Ithaca, NY 14853 (United States); Yagi, Kent; Yunes, Nicolás, E-mail: leostein@astro.cornell.edu [Department of Physics, Montana State University, Bozeman, MT 59717 (United States)

2014-06-10

The gravitational field outside of astrophysical black holes is completely described by their mass and spin frequency, as expressed by the no-hair theorems. These theorems assume vacuum spacetimes, and thus they apply only to black holes and not to stars. Despite this, we analytically find that the gravitational potential of arbitrarily rapid, rigidly rotating stars can still be described completely by only their mass, spin angular momentum, and quadrupole moment. Although these results are obtained in the nonrelativistic limit (to leading order in a weak-field expansion of general relativity, GR), they are also consistent with fully relativistic numerical calculations of rotating neutron stars. This description of the gravitational potential outside the source in terms of just three quantities is approximately universal (independent of equation of state). Such universality may be used to break degeneracies in pulsar and future gravitational wave observations to extract more physics and test GR in the strong-field regime.

Misalignment Effect Function Measurement for Oblique Rotation Axes: Counterintuitive Predictions and Theoretical Extensions

Science.gov (United States)

Ellis, Stephen R.; Adelstein, Bernard D.; Yeom, Kiwon

2013-01-01

The Misalignment Effect Function (MEF) describes the decrement in manual performance associated with a rotation between operators' visual display frame of reference and that of their manual control. It now has been empirically determined for rotation axes oblique to canonical body axes and is compared with the MEF previously measured for rotations about canonical axes. A targeting rule, called the Secant Rule, based on these earlier measurements is derived from a hypothetical process and shown to describe some of the data from three previous experiments. It explains the motion trajectories determined for rotations less than 65deg in purely kinematic terms without the need to appeal to a mental rotation process. Further analysis of this rule in three dimensions applied to oblique rotation axes leads to a somewhat surprising expectation that the difficulty posed by rotational misalignment should get harder as the required movement is shorter. This prediction is confirmed. Geometry underlying this rule also suggests analytic extensions for predicting more generally the difficulty of making movements in arbitrary directions subject to arbitrary misalignments.

Human cortical activity related to unilateral movements. A high resolution EEG study.

Science.gov (United States)

Urbano, A; Babiloni, C; Onorati, P; Babiloni, F

1996-12-20

In the present study a modern high resolution electroencephalography (EEG) technique was used to investigate the dynamic functional topography of human cortical activity related to simple unilateral internally triggered finger movements. The sensorimotor area (M1-S1) contralateral to the movement as well as the supplementary motor area (SMA) and to a lesser extent the ipsilateral M1-S1 were active during the preparation and execution of these movements. These findings suggest that both hemispheres may cooperate in both planning and production of simple unilateral volitional acts.

Movement-related theta rhythm in humans: coordinating self-directed hippocampal learning.

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Raphael Kaplan

Full Text Available The hippocampus is crucial for episodic or declarative memory and the theta rhythm has been implicated in mnemonic processing, but the functional contribution of theta to memory remains the subject of intense speculation. Recent evidence suggests that the hippocampus might function as a network hub for volitional learning. In contrast to human experiments, electrophysiological recordings in the hippocampus of behaving rodents are dominated by theta oscillations reflecting volitional movement, which has been linked to spatial exploration and encoding. This literature makes the surprising cross-species prediction that the human hippocampal theta rhythm supports memory by coordinating exploratory movements in the service of self-directed learning. We examined the links between theta, spatial exploration, and memory encoding by designing an interactive human spatial navigation paradigm combined with multimodal neuroimaging. We used both non-invasive whole-head Magnetoencephalography (MEG to look at theta oscillations and Functional Magnetic Resonance Imaging (fMRI to look at brain regions associated with volitional movement and learning. We found that theta power increases during the self-initiation of virtual movement, additionally correlating with subsequent memory performance and environmental familiarity. Performance-related hippocampal theta increases were observed during a static pre-navigation retrieval phase, where planning for subsequent navigation occurred. Furthermore, periods of the task showing movement-related theta increases showed decreased fMRI activity in the parahippocampus and increased activity in the hippocampus and other brain regions that strikingly overlap with the previously observed volitional learning network (the reverse pattern was seen for stationary periods. These fMRI changes also correlated with participant's performance. Our findings suggest that the human hippocampal theta rhythm supports memory by coordinating

Rotator cuff tendon connections with the rotator cable.

Science.gov (United States)

Rahu, Madis; Kolts, Ivo; Põldoja, Elle; Kask, Kristo

2017-07-01

The literature currently contains no descriptions of the rotator cuff tendons, which also describes in relation to the presence and characteristics of the rotator cable (anatomically known as the ligamentum semicirculare humeri). The aim of the current study was to elucidate the detailed anatomy of the rotator cuff tendons in association with the rotator cable. Anatomic dissection was performed on 21 fresh-frozen shoulder specimens with an average age of 68 years. The rotator cuff tendons were dissected from each other and from the glenohumeral joint capsule, and the superior glenohumeral, coracohumeral, coracoglenoidal and semicircular (rotator cable) ligaments were dissected. Dissection was performed layer by layer and from the bursal side to the joint. All ligaments and tendons were dissected in fine detail. The rotator cable was found in all specimens. It was tightly connected to the supraspinatus (SSP) tendon, which was partly covered by the infraspinatus (ISP) tendon. The posterior insertion area of the rotator cable was located in the region between the middle and inferior facets of the greater tubercle of the humerus insertion areas for the teres minor (TM), and ISP tendons were also present and fibres from the SSP extended through the rotator cable to those areas. The connection between the rotator cable and rotator cuff tendons is tight and confirms the suspension bridge theory for rotator cuff tears in most areas between the SSP tendons and rotator cable. In its posterior insertion area, the rotator cable is a connecting structure between the TM, ISP and SSP tendons. These findings might explain why some patients with relatively large rotator cuff tears can maintain seamless shoulder function.

Intermittent θ burst stimulation over primary motor cortex enhances movement-related β synchronisation.

Science.gov (United States)

Hsu, Ya-Fang; Liao, Kwong-Kum; Lee, Po-Lei; Tsai, Yun-An; Yeh, Chia-Lung; Lai, Kuan-Lin; Huang, Ying-Zu; Lin, Yung-Yang; Lee, I-Hui

2011-11-01

The objective of this study is to investigate how transcranial magnetic intermittent theta burst stimulation (iTBS) with a prolonged protocol affects human cortical excitability and movement-related oscillations. Using motor-evoked potentials (MEPs) and movement-related magnetoencephalography (MEG), we assessed the changes of corticospinal excitability and cortical oscillations after iTBS with double the conventional stimulation time (1200 pulses, iTBS1200) over the primary motor cortex (M1) in 10 healthy subjects. Continuous TBS (cTBS1200) and sham stimulation served as controls. iTBS1200 facilitated MEPs evoked from the conditioned M1, while inhibiting MEPs from the contralateral M1 for 30 min. By contrast, cTBS1200 inhibited MEPs from the conditioned M1. Importantly, empirical mode decomposition-based MEG analysis showed that the amplitude of post-movement beta synchronisation (16-26 Hz) was significantly increased by iTBS1200 at the conditioned M1, but was suppressed at the nonconditioned M1. Alpha (8-13 Hz) and low gamma-ranged (35-45 Hz) rhythms were not notably affected. Movement kinetics remained consistent throughout. TBS1200 modulated corticospinal excitability in parallel with the direction of conventional paradigms with modestly prolonged efficacy. Moreover, iTBS1200 increased post-movement beta synchronisation of the stimulated M1, and decreased that of the contralateral M1, probably through interhemispheric interaction. Our results provide insight into the underlying mechanism of TBS and reinforce the connection between movement-related beta synchronisation and corticospinal output. Copyright © 2011 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

A direct comparison of spine rotational stiffness and dynamic spine stability during repetitive lifting tasks.

Science.gov (United States)

Graham, Ryan B; Brown, Stephen H M

2012-06-01

Stability of the spinal column is critical to bear loads, allow movement, and at the same time avoid injury and pain. However, there has been a debate in recent years as to how best to define and quantify spine stability, with the outcome being that different methods are used without a clear understanding of how they relate to one another. Therefore, the goal of the present study was to directly compare lumbar spine rotational stiffness, calculated with an EMG-driven biomechanical model, to local dynamic spine stability calculated using Lyapunov analyses of kinematic data, during a series of continuous dynamic lifting challenges. Twelve healthy male subjects performed 30 repetitive lifts under three varying load and three varying rate conditions. With an increase in the load lifted (constant rate) there was a significant increase in mean, maximum, and minimum spine rotational stiffness (pstiffness (pstiffness and a non-significant decrease in local dynamic stability (p>0.05). Weak linear relationships were found for the varying rate conditions (r=-0.02 to -0.27). The results suggest that spine rotational stiffness and local dynamic stability are closely related to one another, as they provided similar information when movement rate was controlled. However, based on the results from the changing lifting rate conditions, it is evident that both models provide unique information and that future research is required to completely understand the relationship between the two models. Using both techniques concurrently may provide the best information regarding the true effects of (in) stability under different loading and movement scenarios, and in comparing healthy and clinical populations. Copyright © 2012 Elsevier Ltd. All rights reserved.

Rotating collapse of stellar iron cores in general relativity

International Nuclear Information System (INIS)

Ott, C D; Dimmelmeier, H; Marek, A; Janka, H-T; Zink, B; Hawke, I; Schnetter, E

2007-01-01

We present results from the first 2 + 1 and 3 + 1 simulations of the collapse of rotating stellar iron cores in general relativity employing a finite-temperature equation of state and an approximate treatment of deleptonization during collapse. We compare full 3 + 1 and conformally-flat spacetime evolution methods and find that the conformally-flat treatment is sufficiently accurate for the core-collapse supernova problem. We focus on the gravitational wave (GW) emission from rotating collapse, core bounce and early postbounce phases. Our results indicate that the GW signature of these phases is much more generic than previously estimated. In addition, we track the growth of a nonaxisymmetric instability of dominant m = 1 character in two of our models that leads to prolonged narrow-band GW emission at ∼920-930 Hz over several tens of milliseconds

Movement of the sacroiliac joint during the Active Straight Leg Raise test in patients with long-lasting severe sacroiliac joint pain.

Science.gov (United States)

Kibsgård, Thomas J; Röhrl, Stephan M; Røise, Olav; Sturesson, Bengt; Stuge, Britt

2017-08-01

The Active Straight Leg Raise is a functional test used in the assessment of pelvic girdle pain, and has shown to have good validity, reliability and responsiveness. The Active Straight Leg Raise is considered to examine the patients' ability to transfer load through the pelvis. It has been hypothesized that patients with pelvic girdle pain lack the ability to stabilize the pelvic girdle, probably due to instability or increased movement of the sacroiliac joint. This study examines the movement of the sacroiliac joints during the Active Straight Leg Raise in patients with pelvic girdle pain. Tantalum markers were inserted in the dorsal sacrum and ilium of 12 patients with long-lasting pelvic girdle pain scheduled for sacroiliac joint fusion surgery. Two to three weeks later movement of the sacroiliac joints during the Active Straight Leg Raise was measured with radiostereometric analysis. Small movements were detected. There was larger movement of the sacroiliac joint of the rested leg's sacroiliac joint compared to the lifted leg's side. A mean backward rotation of 0.8° and inward tilt of 0.3° were seen in the rested leg's sacroiliac joint. The movements of the sacroiliac joints during the Active Straight Leg Raise are small. There was a small backward rotation of the innominate bone relative to sacrum on the rested leg's side. Our findings contradict an earlier understanding that a forward rotation of the lifted leg's innominate occur while performing the Active Straight Leg Raise. Copyright © 2017. Published by Elsevier Ltd.

[A new kinematics method of determing elbow rotation axis and evaluation of its feasibility].

Science.gov (United States)

Han, W; Song, J; Wang, G Z; Ding, H; Li, G S; Gong, M Q; Jiang, X Y; Wang, M Y

2016-04-18

To study a new positioning method of elbow external fixation rotation axis, and to evaluate its feasibility. Four normal adult volunteers and six Sawbone elbow models were brought into this experiment. The kinematic data of five elbow flexion were collected respectively by optical positioning system. The rotation axes of the elbow joints were fitted by the least square method. The kinematic data and fitting results were visually displayed. According to the fitting results, the average moving planes and rotation axes were calculated. Thus, the rotation axes of new kinematic methods were obtained. By using standard clinical methods, the entrance and exit points of rotation axes of six Sawbone elbow models were located under X-ray. And The kirschner wires were placed as the representatives of rotation axes using traditional positioning methods. Then, the entrance point deviation, the exit point deviation and the angle deviation of two kinds of located rotation axes were compared. As to the four volunteers, the indicators represented circular degree and coplanarity of elbow flexion movement trajectory of each volunteer were both about 1 mm. All the distance deviations of the moving axes to the average moving rotation axes of the five volunteers were less than 3 mm. All the angle deviations of the moving axes to the average moving rotation axes of the five volunteers were less than 5°. As to the six Sawbone models, the average entrance point deviations, the average exit point deviations and the average angle deviations of two different rotation axes determined by two kinds of located methods were respectively 1.697 2 mm, 1.838 3 mm and 1.321 7°. All the deviations were very small. They were all in an acceptable range of clinical practice. The values that represent circular degree and coplanarity of volunteer's elbow single curvature movement trajectory are very small. The result shows that the elbow single curvature movement can be regarded as the approximate fixed

Realization of masticatory movement by 3-dimensional simulation of the temporomandibular joint and the masticatory muscles.

Science.gov (United States)

Park, Jong-Tae; Lee, Jae-Gi; Won, Sung-Yoon; Lee, Sang-Hee; Cha, Jung-Yul; Kim, Hee-Jin

2013-07-01

Masticatory muscles are closely involved in mastication, pronunciation, and swallowing, and it is therefore important to study the specific functions and dynamics of the mandibular and masticatory muscles. However, the shortness of muscle fibers and the diversity of movement directions make it difficult to study and simplify the dynamics of mastication. The purpose of this study was to use 3-dimensional (3D) simulation to observe the functions and movements of each of the masticatory muscles and the mandible while chewing. To simulate the masticatory movement, computed tomographic images were taken from a single Korean volunteer (30-year-old man), and skull image data were reconstructed in 3D (Mimics; Materialise, Leuven, Belgium). The 3D-reconstructed masticatory muscles were then attached to the 3D skull model. The masticatory movements were animated using Maya (Autodesk, San Rafael, CA) based on the mandibular motion path. During unilateral chewing, the mandible was found to move laterally toward the functional side by contracting the contralateral lateral pterygoid and ipsilateral temporalis muscles. During the initial mouth opening, only hinge movement was observed at the temporomandibular joint. During this period, the entire mandible rotated approximately 13 degrees toward the bicondylar horizontal plane. Continued movement of the mandible to full mouth opening occurred simultaneously with sliding and hinge movements, and the mandible rotated approximately 17 degrees toward the center of the mandibular ramus. The described approach can yield data for use in face animation and other simulation systems and for elucidating the functional components related to contraction and relaxation of muscles during mastication.

Sleep staging with movement-related signals.

Science.gov (United States)

Jansen, B H; Shankar, K

1993-05-01

Body movement related signals (i.e., activity due to postural changes and the ballistocardiac effort) were recorded from six normal volunteers using the static-charge-sensitive bed (SCSB). Visual sleep staging was performed on the basis of simultaneously recorded EEG, EMG and EOG signals. A statistical classification technique was used to determine if reliable sleep staging could be performed using only the SCSB signal. A classification rate of between 52% and 75% was obtained for sleep staging in the five conventional sleep stages and the awake state. These rates improved from 78% to 89% for classification between awake, REM and non-REM sleep and from 86% to 98% for awake versus asleep classification.

The Hα Emission of Nearby M Dwarfs and its Relation to Stellar Rotation

Science.gov (United States)

Newton, Elisabeth R.; Irwin, Jonathan; Charbonneau, David; Berlind, Perry; Calkins, Michael L.; Mink, Jessica

2017-01-01

The high-energy emission from low-mass stars is mediated by the magnetic dynamo. Although the mechanisms by which fully convective stars generate large-scale magnetic fields are not well understood, it is clear that, as for solar-type stars, stellar rotation plays a pivotal role. We present 270 new optical spectra of low-mass stars in the Solar Neighborhood. Combining our observations with those from the literature, our sample comprises 2202 measurements or non-detections of Hα emission in nearby M dwarfs. This includes 466 with photometric rotation periods. Stars with masses between 0.1 and 0.6 M⊙ are well-represented in our sample, with fast and slow rotators of all masses. We observe a threshold in the mass-period plane that separates active and inactive M dwarfs. The threshold coincides with the fast-period edge of the slowly rotating population, at approximately the rotation period at which an era of rapid rotational evolution appears to cease. The well-defined active/inactive boundary indicates that Hα activity is a useful diagnostic for stellar rotation period, e.g., for target selection for exoplanet surveys, and we present a mass-period relation for inactive M dwarfs. We also find a significant, moderate correlation between LHα/Lbol and variability amplitude: more active stars display higher levels of photometric variability. Consistent with previous work, our data show that rapid rotators maintain a saturated value of LHα/Lbol. Our data also show a clear power-law decay in LHα/Lbol with Rossby number for slow rotators, with an index of -1.7 ± 0.1.

Do Activity Level Outcome Measures Commonly Used in Neurological Practice Assess Upper-Limb Movement Quality?

Science.gov (United States)

Demers, Marika; Levin, Mindy F

2017-07-01

Movement is described in terms of task-related end point characteristics in external space and movement quality (joint rotations in body space). Assessment of upper-limb (UL) movement quality can assist therapists in designing effective treatment approaches for retraining lost motor elements and provide more detailed measurements of UL motor improvements over time. To determine the extent to which current activity level outcome measures used in neurological practice assess UL movement quality. Outcome measures assessing arm/hand function at the International Classification of Function activity level recommended by neurological clinical practice guidelines were reviewed. Measures assessing the UL as part of a general mobility assessment, those strictly evaluating body function/structure or participation, and paediatric measures were excluded. In all, 15 activity level outcome measures were identified; 9 measures assess how movement is performed by measuring either end point characteristics or movement quality. However, except for the Reaching Performance Scale for Stroke and the Motor Evaluation Scale for Upper Extremity in Stroke Patients, these measures only account for deficits indirectly by giving a partial score if movements are slower or if the person experiences difficulties. Six outcome measures neither assess any parameters related to movement quality, nor distinguish between improvements resulting from motor compensation or recovery of desired movement strategies. Current activity measures may not distinguish recovery from compensation and adequately track changes in movement quality over time. Movement quality may be incorporated into clinical assessment using observational kinematics with or without low-cost motion tracking technology.

Calibrated Tully-fisher Relations For Improved Photometric Estimates Of Disk Rotation Velocities

NARCIS (Netherlands)

Reyes, Reinabelle; Mandelbaum, R.; Gunn, J. E.; Pizagno II, Jim

We present calibrated scaling relations (also referred to as Tully-Fisher relations or TFRs) between rotation velocity and photometric quantities-- absolute magnitude, stellar mass, and synthetic magnitude (a linear combination of absolute magnitude and color)-- of disk galaxies at z 0.1. First, we

Breakdown of the Stokes-Einstein Relation for the Rotational Diffusivity of Polymer Grafted Nanoparticles in Polymer Melts.

Science.gov (United States)

Maldonado-Camargo, Lorena; Rinaldi, Carlos

2016-11-09

We report observations of breakdown of the Stokes-Einstein relation for the rotational diffusivity of polymer-grafted spherical nanoparticles in polymer melts. The rotational diffusivity of magnetic nanoparticles coated with poly(ethylene glycol) dispersed in poly(ethylene glycol) melts was determined through dynamic magnetic susceptibility measurements of the collective rotation of the magnetic nanoparticles due to imposed time-varying magnetic torques. These measurements clearly demonstrate the existence of a critical molecular weight for the melt polymer, below which the Stokes-Einstein relation accurately describes the rotational diffusivity of the polymer-grafted nanoparticles and above which the Stokes-Einstein relation ceases to apply. This critical molecular weight was found to correspond to a chain contour length that approximates the hydrodynamic diameter of the nanoparticles.

Vestibular-related frontal cortical areas and their roles in smooth-pursuit eye movements: representation of neck velocity, neck-vestibular interactions and memory-based smooth-pursuit

Directory of Open Access Journals (Sweden)

Kikuro eFukushima

2011-12-01

Full Text Available Smooth-pursuit eye movements are voluntary responses to small slow-moving objects in the fronto-parallel plane. They evolved in primates, who possess high-acuity foveae, to ensure clear vision about the moving target. The primate frontal cortex contains two smooth-pursuit related areas; the caudal part of the frontal eye fields (FEF and the supplementary eye fields (SEF. Both areas receive vestibular inputs. We review functional differences between the two areas in smooth-pursuit. Most FEF pursuit neurons signal pursuit parameters such as eye velocity and gaze-velocity, and are involved in cancelling the vestibulo-ocular reflex by linear addition of vestibular and smooth-pursuit responses. In contrast, gaze-velocity signals are rarely represented in the SEF. Most FEF pursuit neurons receive neck velocity inputs, while discharge modulation during pursuit and trunk-on-head rotation adds linearly. Linear addition also occurs between neck velocity responses and vestibular responses during head-on-trunk rotation in a task-dependent manner. During cross-axis pursuit-vestibular interactions, vestibular signals effectively initiate predictive pursuit eye movements. Most FEF pursuit neurons discharge during the interaction training after the onset of pursuit eye velocity, making their involvement unlikely in the initial stages of generating predictive pursuit. Comparison of representative signals in the two areas and the results of chemical inactivation during a memory-based smooth-pursuit task indicate they have different roles; the SEF plans smooth-pursuit including working memory of motion-direction, whereas the caudal FEF generates motor commands for pursuit eye movements. Patients with idiopathic Parkinson’s disease were asked to perform this task, since impaired smooth-pursuit and visual working memory deficit during cognitive tasks have been reported in most patients. Preliminary results suggested specific roles of the basal ganglia in memory

Maxillary movement in distraction osteogenesis using internal devices in cleft palate patients.

Science.gov (United States)

Tomita, Daisuke; Omura, Susumu; Ozaki, Shusaku; Shimazaki, Kazuo; Fukuyama, Eiji; Tohnai, Iwai; Torikai, Katsuyuki

2011-03-01

The purpose of this cephalometric study was to compare the actual movement with the planned movement of the maxilla by using internal maxillary distraction in cleft lip and palate patients. Twelve patients, including eight with unilateral and four with bilateral cleft lip and palate, underwent maxillary advancement with internal maxillary distractors. Lateral cephalometric radiographs obtained preoperatively, predistraction, and postdistraction were used for analysis. The movement of the maxilla, angular change of the internal devices and rotation of the mandible were measured at each stage, and the planned vector of advancement predicted from the placement vector of the distractors was compared with the actual vector. Internal maxillary distractors were rotated in a clockwise direction during the distraction period. The angular change of the distractors was 7.7°. The amount of actual advancement at anterior nasal spine with distraction was 6.3 mm, which represented about 70% of the distance of activation of distraction. The actual advanced vector at anterior nasal spine was 9.7° smaller than the planned vector. The mandible underwent a clockwise rotation of 3.5°. In the internal distraction technique, the maxilla was advanced inferiorly to the planned vector and with a slight clockwise rotation. These results are useful for surgical planning when using internal distractors.

Attentional Modulation of Somatosensory Processing During the Anticipation of Movements Accompanying Pain: An Event-Related Potential Study.

Science.gov (United States)

Clauwaert, Amanda; Torta, Diana M; Danneels, Lieven; Van Damme, Stefaan

2018-02-01

Attending to pain-relevant information is crucial to protect us from physical harm. Behavioral studies have already suggested that during anticipation of pain somatosensory input at the body location under threat is prioritized. However, research using daily life cues for pain, especially movements, is lacking. Furthermore, to our knowledge, no studies have investigated cortical processing associated with somatosensory processing during threatened movements. The current study aims to investigate whether movements accompanying pain automatically steer attention toward somatosensory input at the threatened location, affecting somatosensory evoked potentials (SEPs). Healthy volunteers were cued to perform movements with the left or the right hand, and one of these movements could be accompanied by pain on the moving hand. During movement anticipation, a task-irrelevant tactile stimulus was presented to the threatened or pain-free hand to evoke SEPs. During anticipation of movements accompanying pain, the N120 component was increased for tactile stimuli at the threatened relative to the hand without pain. Moreover, the P200 SEP was enhanced during anticipation of movements accompanying pain relative to movements without pain, irrespective of which hand was stimulated. These findings show that the anticipation of pain-accompanying movements may affect the processing of somatosensory input, and that this is likely to be driven by attentional processes. This study shows that the anticipation of pain-related movements automatically biases attention toward stimuli at a pain-related location, measured according to SEPs. The present study provides important new insights in the interplay between pain and attention, and its consequences at the cortical level. Copyright © 2017 The American Pain Society. Published by Elsevier Inc. All rights reserved.

Primary Motor Cortex Excitability Is Modulated During the Mental Simulation of Hand Movement.

Science.gov (United States)

Hyde, Christian; Fuelscher, Ian; Lum, Jarrad A G; Williams, Jacqueline; He, Jason; Enticott, Peter G

2017-02-01

It is unclear whether the primary motor cortex (PMC) is involved in the mental simulation of movement [i.e., motor imagery (MI)]. The present study aimed to clarify PMC involvement using a highly novel adaptation of the hand laterality task (HLT). Participants were administered single-pulse transcranial magnetic stimulation (TMS) to the hand area of the left PMC (hPMC) at either 50 ms, 400 ms, or 650 ms post stimulus presentation. Motor-evoked potentials (MEPs) were recorded from the right first dorsal interosseous via electromyography. To avoid the confound of gross motor response, participant response (indicating left or right hand) was recorded via eye tracking. Participants were 22 healthy adults (18 to 36 years), 16 whose behavioral profile on the HLT was consistent with the use of a MI strategy (MI users). hPMC excitability increased significantly during HLT performance for MI users, evidenced by significantly larger right hand MEPs following single-pulse TMS 50 ms, 400 ms, and 650 ms post stimulus presentation relative to baseline. Subsequent analysis showed that hPMC excitability was greater for more complex simulated hand movements, where hand MEPs at 50 ms were larger for biomechanically awkward movements (i.e., hands requiring lateral rotation) compared to simpler movements (i.e., hands requiring medial rotation). These findings provide support for the modulation of PMC excitability during the HLT attributable to MI, and may indicate a role for the PMC during MI. (JINS, 2017, 23, 185-193).

The effects of elevated endogenous GABA levels on movement-related network oscillations.

Science.gov (United States)

Muthukumaraswamy, S D; Myers, J F M; Wilson, S J; Nutt, D J; Lingford-Hughes, A; Singh, K D; Hamandi, K

2013-02-01

The EEG/MEG signal is generated primarily by the summation of the post-synaptic potentials of cortical principal cells. At a microcircuit level, these glutamatergic principal cells are reciprocally connected to GABAergic interneurons and cortical oscillations are thought to be dependent on the balance of excitation and inhibition between these cell types. To investigate the dependence of movement-related cortical oscillations on excitation-inhibition balance, we pharmacologically manipulated the GABA system using tiagabine, which blocks GABA Transporter 1(GAT-1), the GABA uptake transporter and increases endogenous GABA activity. In a blinded, placebo-controlled, crossover design, in 15 healthy participants we administered either 15mg of tiagabine or a placebo. We recorded whole-head magnetoencephalograms, while the participants performed a movement task, prior to, one hour post, three hour post and five hour post tiagabine ingestion. Using time-frequency analysis of beamformer source reconstructions, we quantified the baseline level of beta activity (15-30Hz), the post-movement beta rebound (PMBR), beta event-related desynchronisation (beta-ERD) and movement-related gamma synchronisation (MRGS) (60-90Hz). Our results demonstrated that tiagabine, and hence elevated endogenous GABA levels causes, an elevation of baseline beta power, enhanced beta-ERD and reduced PMBR, but no modulation of MRGS. Comparing our results to recent literature (Hall et al., 2011) we suggest that beta-ERD may be a GABAA receptor mediated process while PMBR may be GABAB receptor mediated. Copyright © 2012 Elsevier Inc. All rights reserved.

How well does Invisalign work? A prospective clinical study evaluating the efficacy of tooth movement with Invisalign.

Science.gov (United States)

Kravitz, Neal D; Kusnoto, Budi; BeGole, Ellen; Obrez, Ales; Agran, Brent

2009-01-01

The purpose of this prospective clinical study was to evaluate the efficacy of tooth movement with removable polyurethane aligners (Invisalign, Align Technology, Santa Clara, Calif). The study sample included 37 patients treated with Anterior Invisalign. Four hundred one anterior teeth (198 maxillary and 203 mandibular) were measured on the virtual Treat models. The virtual model of the predicted tooth position was superimposed over the virtual model of the achieved tooth position, created from the posttreatment impression, and the 2 models were superimposed over their stationary posterior teeth by using ToothMeasure, Invisalign's proprietary superimposition software. The amount of tooth movement predicted was compared with the amount achieved after treatment. The types of movements studied were expansion, constriction, intrusion, extrusion, mesiodistal tip, labiolingual tip, and rotation. The mean accuracy of tooth movement with Invisalign was 41%. The most accurate movement was lingual constriction (47.1%), and the least accurate movement was extrusion (29.6%)- specifically, extrusion of the maxillary (18.3%) and mandibular (24.5%) central incisors, followed by mesiodistal tipping of the mandibular canines (26.9%). The accuracy of canine rotation was significantly lower than that of all other teeth, with the exception of the maxillary lateral incisors. At rotational movements greater than 15 degrees, the accuracy of rotation for the maxillary canines fell significantly. Lingual crown tip was significantly more accurate than labial crown tip, particularly for the maxillary incisors. There was no statistical difference in accuracy between maxillary and mandibular teeth of the same tooth type for any movements studied. We still have much to learn regarding the biomechanics and efficacy of the Invisalign system. A better understanding of Invisalign's ability to move teeth might help the clinician select suitable patients for treatment, guide the proper sequencing of

HEAD MOVEMENT DURING WALKING IN THE CAT

Science.gov (United States)

ZUBAIR, HUMZA N.; BELOOZEROVA, IRINA N.; SUN, HAI; MARLINSKI, VLADIMIR

2016-01-01

Knowledge of how the head moves during locomotion is essential for understanding how locomotion is controlled by sensory systems of the head. We have analyzed head movements of the cat walking along a straight flat pathway in the darkness and light. We found that cats' head left-right translations, and roll and yaw rotations oscillated once per stride, while fore-aft and vertical translations, and pitch rotations oscillated twice. The head reached its highest vertical positions during second half of each forelimb swing, following maxima of the shoulder/trunk by 20–90°. Nose-up rotation followed head upward translation by another 40–90° delay. The peak-to-peak amplitude of vertical translation was ~1.5 cm and amplitude of pitch rotation was ~3°. Amplitudes of lateral translation and roll rotation were ~1 cm and 1.5–3°, respectively. Overall, cats' heads were neutral in roll and 10–30° nose-down, maintaining horizontal semicircular canals and utriculi within 10° of the earth horizontal. The head longitudinal velocity was 0.5–1 m/s, maximal upward and downward linear velocities were ~0.05 and ~0.1 m/s, respectively, and maximal lateral velocity was ~0.05 m/s. Maximal velocities of head pitch rotation were 20–50 °/s. During walking in light, cats stood 0.3–0.5 cm taller and held their head 0.5–2 cm higher than in darkness. Forward acceleration was 25–100% higher and peak-to-peak amplitude of head pitch oscillations was ~20 °/s larger. We concluded that, during walking, the head of the cat is held actively. Reflexes appear to play only a partial role in determining head movement, and vision might further diminish their role. PMID:27339731

A note on relative equilibria in a rotating shallow water layer

KAUST Repository

Ait Abderrahmane, Hamid

2013-05-08

Relative equilibria of two and three satellite vortices in a rotating shallow water layer have been recorded via particle image velocimetry (PIV) and their autorotation speed was estimated. This study shows that these equilibria retain the fundamental characteristics of Kelvin\\'s equilibria, and could be adequately described by the classical idealized point vortex theory. The same conclusion can also be inferred using the experimental dataset of Bergmann et al. (J. Fluid Mech., vol. 679, 2011, pp. 415-431; J. Fluid Mech., vol. 691, 2012, pp. 605-606) if the assigned field\\'s contribution to pattern rotation is included. © 2013 Cambridge University Press.

Three-dimensional analysis of otolith-ocular reflex during eccentric rotation in humans.

Science.gov (United States)

Takimoto, Yasumitsu; Imai, Takao; Okumura, Tomoko; Takeda, Noriaki; Inohara, Hidenori

2016-10-01

When a participant is rotated while displaced from the axis of rotation (eccentric rotation, ER), both rotational stimulation and linear acceleration are applied to the participant. As linear acceleration stimulates the otolith, the vestibulo-ocular reflex (VOR) caused by the otolith (linear VOR; lVOR) would be induced during ER. Ten participants were rotated sinusoidally at a maximum angular velocity of 50°/s and at frequencies of 0.1, 0.3, 0.5, and 0.7Hz. The radius of rotation during ER was 90cm. The participants sat on a chair at three different positions: on the axis (center rotation, CR), at 90cm backward from the axis (nose-in ER, NI-ER) and at 90cm forward from the axis (nose-out ER, NO-ER). Their eye movements during rotation were recorded and analyzed three-dimensionally. The VOR gain during NI-ER was lower at 0.5 and 0.7Hz, and that during NO-ER was higher at 0.3, 0.5, and 0.7Hz than during CR. These results indicate that lVOR actually worked at 0.5 and 0.7Hz during ER and that the enhancement and decline of the VOR gain relative to the VOR gain during CR was seen in humans. Thus, we suggest that otolith function can be assessed via rotational testing of NI-ER and NO-ER. Copyright © 2016 Elsevier Ireland Ltd and Japan Neuroscience Society. All rights reserved.

Random motion and Brownian rotation

International Nuclear Information System (INIS)

Wyllie, G.

1980-01-01

The course is centred on the Brownian motion - the random movement of molecules arising from thermal fluctuations of the surrounding medium - and starts with the classical theory of A. Einstein, M.v. Smoluchowski and P. Langevin. The first part of this article is quite elementary, and several of the questions raised in it have been instructively treated in a much more sophisticated way in recent reviews by Pomeau and Resibois and by Fox. This simple material may nevertheless be helpful to some readers whose main interest lies in approaching the work on Brownian rotation reviewed in the latter part of the present article. The simplest, and most brutally idealised, problem in our field of interest is that of the random walk in one dimension of space. Its solution leads on, through the diffusivity-mobility relation of Einstein, to Langevin's treatment of the Brownian motion. The application of these ideas to the movement of a molecule in a medium of similar molecules is clearly unrealistic, and much energy has been devoted to finding a suitable generalisation. We shall discuss in particular ideas due to Green, Zwanzig and Mori. (orig./WL)

Efficacy of clear aligners in controlling orthodontic tooth movement: a systematic review.

Science.gov (United States)

Rossini, Gabriele; Parrini, Simone; Castroflorio, Tommaso; Deregibus, Andrea; Debernardi, Cesare L

2015-09-01

To assess the scientific evidence related to the efficacy of clear aligner treatment (CAT) in controlling orthodontic tooth movement. PubMed, PMC, NLM, Embase, Cochrane Central Register of Controlled Clinical Trials, Web of Knowledge, Scopus, Google Scholar, and LILACs were searched from January 2000 to June 2014 to identify all peer-reviewed articles potentially relevant to the review. Methodological shortcomings were highlighted and the quality of the studies was ranked using the Cochrane Tool for Risk of Bias Assessment. Eleven relevant articles were selected (two Randomized Clinical Trials (RCT), five prospective non-randomized, four retrospective non-randomized), and the risk of bias was moderate for six studies and unclear for the others. The amount of mean intrusion reported was 0.72 mm. Extrusion was the most difficult movement to control (30% of accuracy), followed by rotation. Upper molar distalization revealed the highest predictability (88%) when a bodily movement of at least 1.5 mm was prescribed. A decrease of the Little's Index (mandibular arch: 5 mm; maxillary arch: 4 mm) was observed in aligning arches. CAT aligns and levels the arches; it is effective in controlling anterior intrusion but not anterior extrusion; it is effective in controlling posterior buccolingual inclination but not anterior buccolingual inclination; it is effective in controlling upper molar bodily movements of about 1.5 mm; and it is not effective in controlling rotation of rounded teeth in particular. However, the results of this review should be interpreted with caution because of the number, quality, and heterogeneity of the studies.

Rotating shift work, sleep, and accidents related to sleepiness in hospital nurses

Science.gov (United States)

Gold, D. R.; Rogacz, S.; Bock, N.; Tosteson, T. D.; Baum, T. M.; Speizer, F. E.; Czeisler, C. A.

1992-01-01

A hospital-based survey on shift work, sleep, and accidents was carried out among 635 Massachusetts nurses. In comparison to nurses who worked only day/evening shifts, rotators had more sleep/wake cycle disruption and nodded off more at work. Rotators had twice the odds of nodding off while driving to or from work and twice the odds of a reported accident or error related to sleepiness. Application of circadian principles to the design of hospital work schedules may result in improved health and safety for nurses and patients.

Classification of Hand Grasp Kinetics and Types Using Movement-Related Cortical Potentials and EEG Rhythms

Directory of Open Access Journals (Sweden)

Mads Jochumsen

2017-01-01

Full Text Available Detection of single-trial movement intentions from EEG is paramount for brain-computer interfacing in neurorehabilitation. These movement intentions contain task-related information and if this is decoded, the neurorehabilitation could potentially be optimized. The aim of this study was to classify single-trial movement intentions associated with two levels of force and speed and three different grasp types using EEG rhythms and components of the movement-related cortical potential (MRCP as features. The feature importance was used to estimate encoding of discriminative information. Two data sets were used. 29 healthy subjects executed and imagined different hand movements, while EEG was recorded over the contralateral sensorimotor cortex. The following features were extracted: delta, theta, mu/alpha, beta, and gamma rhythms, readiness potential, negative slope, and motor potential of the MRCP. Sequential forward selection was performed, and classification was performed using linear discriminant analysis and support vector machines. Limited classification accuracies were obtained from the EEG rhythms and MRCP-components: 0.48±0.05 (grasp types, 0.41±0.07 (kinetic profiles, motor execution, and 0.39±0.08 (kinetic profiles, motor imagination. Delta activity contributed the most but all features provided discriminative information. These findings suggest that information from the entire EEG spectrum is needed to discriminate between task-related parameters from single-trial movement intentions.

Dynamic characteristics of otolith ocular response during counter rotation about dual yaw axes in mice.

Science.gov (United States)

Shimizu, N; Wood, S; Kushiro, K; Yanai, S; Perachio, A; Makishima, T

2015-01-29

The central vestibular system plays an important role in higher neural functions such as self-motion perception and spatial orientation. Its ability to store head angular velocity is called velocity storage mechanism (VSM), which has been thoroughly investigated across a wide range of species. However, little is known about the mouse VSM, because the mouse lacks typical ocular responses such as optokinetic after nystagmus or a dominant time constant of vestibulo-ocular reflex for which the VSM is critical. Experiments were conducted to examine the otolith-driven eye movements related to the VSM and verify its characteristics in mice. We used a novel approach to generate a similar rotating vector as a traditional off-vertical axis rotation (OVAR) but with a larger resultant gravito-inertial force (>1g) by using counter rotation centrifugation. Similar to results previously described in other animals during OVAR, two components of eye movements were induced, i.e. a sinusoidal modulatory eye movement (modulation component) on which a unidirectional nystagmus (bias component) was superimposed. Each response is considered to derive from different mechanisms; modulations arise predominantly through linear vestibulo-ocular reflex, whereas for the bias, the VSM is responsible. Data indicate that the mouse also has a well-developed vestibular system through otoliths inputs, showing its highly conserved nature across mammalian species. On the other hand, to reach a plateau state of bias, a higher frequency rotation or a larger gravito-inertial force was considered to be necessary than other larger animals. Compared with modulation, the bias had a more variable profile, suggesting an inherent complexity of higher-order neural processes in the brain. Our data provide the basis for further study of the central vestibular system in mice, however, the underlying individual variability should be taken into consideration. Copyright © 2014 IBRO. Published by Elsevier Ltd. All

Artificial gravity: head movements during short-radius centrifugation

NARCIS (Netherlands)

Young, L. R.; Hecht, H.; Lyne, L. E.; Sienko, K. H.; Cheung, C. C.; Kavelaars, J.

2001-01-01

Short-radius centrifugation is a potential countermeasure to long-term weightlessness. Unfortunately, head movements in a rotating environment induce serious discomfort, non-compensatory vestibulo-ocular reflexes, and subjective illusions of body tilt. In two experiments we investigated the effects

Analysis of rotation-vibration relative equilibria on the example of a tetrahedral four atom molecule

NARCIS (Netherlands)

Efstathiou, K; Sadovskii, DA; Zhilinskii, BI

2004-01-01

We study relative equilibria ( RE) of a nonrigid molecule, which vibrates about a well-defined equilibrium configuration and rotates as a whole. Our analysis unifies the theory of rotational and vibrational RE. We rely on the detailed study of the symmetry group action on the initial and reduced

Contribution of eye position to movement perception.

Science.gov (United States)

Pettorossi, V E; Panichi, R; Bambagioni, D; Grassi, S; Botti, F M

2004-05-01

To investigate the influence of gaze eccentricity on movement perception during asymmetric vestibular stimulation. Subjects (n = 10) were placed on a rotating platform and oscillated asymmetrically in the dark. Subjects were asked to reproduce with a pointer the location in space of a light spot that was turned off at the beginning of the oscillation. The target was presented in centric and eccentric (0 degrees, 20 degrees and 40 degrees) positions. In the centric position a large shift from the real position of the target was observed in the opposite direction to that of the faster vestibular stimulation. The shift increased when the target was placed eccentrically toward the slower vestibular stimulation side and decreased when it was placed in the opposite direction. The dependence of rotation perception on the target position suggests that the eye deviation, imposed by the eccentricity of the target, is able to influence the perception of body movement and may modulate the internal reference frame.

Rotational seismology

Science.gov (United States)

Lee, William H K.

2016-01-01

Rotational seismology is an emerging study of all aspects of rotational motions induced by earthquakes, explosions, and ambient vibrations. It is of interest to several disciplines, including seismology, earthquake engineering, geodesy, and earth-based detection of Einstein’s gravitation waves.Rotational effects of seismic waves, together with rotations caused by soil–structure interaction, have been observed for centuries (e.g., rotated chimneys, monuments, and tombstones). Figure 1a shows the rotated monument to George Inglis observed after the 1897 Great Shillong earthquake. This monument had the form of an obelisk rising over 19 metres high from a 4 metre base. During the earthquake, the top part broke off and the remnant of some 6 metres rotated about 15° relative to the base. The study of rotational seismology began only recently when sensitive rotational sensors became available due to advances in aeronautical and astronomical instrumentations.

On the relative rotational motion between rigid fibers and fluid in turbulent channel flow

Energy Technology Data Exchange (ETDEWEB)

Marchioli, C. [Department of Electrical, Management and Mechanical Engineering, University of Udine, 33100 Udine (Italy); Zhao, L., E-mail: lihao.zhao@ntnu.no [Department of Energy and Process Engineering, Norwegian University of Science and Technology, 7491 Trondheim (Norway); Andersson, H. I. [Department of Electrical, Management and Mechanical Engineering, University of Udine, 33100 Udine (Italy); Department of Energy and Process Engineering, Norwegian University of Science and Technology, 7491 Trondheim (Norway)

2016-01-15

In this study, the rotation of small rigid fibers relative to the surrounding fluid in wall-bounded turbulence is examined by means of direct numerical simulations coupled with Lagrangian tracking. Statistics of the relative (fiber-to-fluid) angular velocity, referred to as slip spin in the present study, are evaluated by modelling fibers as prolate spheroidal particles with Stokes number, St, ranging from 1 to 100 and aspect ratio, λ, ranging from 3 to 50. Results are compared one-to-one with those obtained for spherical particles (λ = 1) to highlight effects due to fiber length. The statistical moments of the slip spin show that differences in the rotation rate of fibers and fluid are influenced by inertia, but depend strongly also on fiber length: Departures from the spherical shape, even when small, are associated with an increase of rotational inertia and prevent fibers from passively following the surrounding fluid. An increase of fiber length, in addition, decouples the rotational dynamics of a fiber from its translational dynamics suggesting that the two motions can be modelled independently only for long enough fibers (e.g., for aspect ratios of order ten or higher in the present simulations)

The Effect of Rotation Stirring on Macrosegregation in Bi-Sn Alloy

Directory of Open Access Journals (Sweden)

Zulaida Yeni Muriani

2017-01-01

Full Text Available Macrosegregation is a defect that difficult to avoid in a metal alloy made by casting method. Macrosegregation can cause decreasing in mechanical properties of casting products. It will reduce their performance in industrial application. Macrosegregation is convinced occur during solidification time in liquid alloy. In the early solidified, The solids move upward/downward in liquid alloy during solidification are considered to contribute on macrosegregation formation. This movement occur due to the density differences between the solid and the surrounding liquid. This research want to observe the effect of stirring on macrosegregation formation for interfering on the movement of initial solidified solid. Stiring with rotation method is applied in this experiment at certain temperature. The temperature and the rotation speed of stirring are varied to observe the effect of rotation stirring on macrosegregation formation. The mold is covered by insulation jacket and kept the bottom part opened in order to obtain the directionally solidification. The result shows that the rotation stirring can change the macrostructure of casting but in case of composition distribution, the macrosegregation still appear. Increasing the rotation stirring will rise solid crystals up and the macrosegregation become more uniform and the treatment is better if conducting at lower temperature.

Actuator assembly including a single axis of rotation locking member

Science.gov (United States)

Quitmeyer, James N.; Benson, Dwayne M.; Geck, Kellan P.

2009-12-08

An actuator assembly including an actuator housing assembly and a single axis of rotation locking member fixedly attached to a portion of the actuator housing assembly and an external mounting structure. The single axis of rotation locking member restricting rotational movement of the actuator housing assembly about at least one axis. The single axis of rotation locking member is coupled at a first end to the actuator housing assembly about a Y axis and at a 90.degree. angle to an X and Z axis providing rotation of the actuator housing assembly about the Y axis. The single axis of rotation locking member is coupled at a second end to a mounting structure, and more particularly a mounting pin, about an X axis and at a 90.degree. angle to a Y and Z axis providing rotation of the actuator housing assembly about the X axis. The actuator assembly is thereby restricted from rotation about the Z axis.

Mental rotation of anthropoid hands: a chronometric study

Directory of Open Access Journals (Sweden)

L.G. Gawryszewski

2007-03-01

Full Text Available It has been shown that mental rotation of objects and human body parts is processed differently in the human brain. But what about body parts belonging to other primates? Does our brain process this information like any other object or does it instead maximize the structural similarities with our homologous body parts? We tried to answer this question by measuring the manual reaction time (MRT of human participants discriminating the handedness of drawings representing the hands of four anthropoid primates (orangutan, chimpanzee, gorilla, and human. Twenty-four right-handed volunteers (13 males and 11 females were instructed to judge the handedness of a hand drawing in palm view by pressing a left/right key. The orientation of hand drawings varied from 0º (fingers upwards to 90º lateral (fingers pointing away from the midline, 180º (fingers downwards and 90º medial (finger towards the midline. The results showed an effect of rotation angle (F(3, 69 = 19.57, P < 0.001, but not of hand identity, on MRTs. Moreover, for all hand drawings, a medial rotation elicited shorter MRTs than a lateral rotation (960 and 1169 ms, respectively, P < 0.05. This result has been previously observed for drawings of the human hand and related to biomechanical constraints of movement performance. Our findings indicate that anthropoid hands are essentially equivalent stimuli for handedness recognition. Since the task involves mentally simulating the posture and rotation of the hands, we wondered if "mirror neurons" could be involved in establishing the motor equivalence between the stimuli and the participants' own hands.

Utilization of optical tracking to validate a software-driven isocentric approach to robotic couch movements for proton radiotherapy

International Nuclear Information System (INIS)

Hsi, Wen C.; Zeidan, Omar A.; Law, Aaron; Schreuder, Andreas N.

2014-01-01

Purpose: An optical tracking and positioning system (OTPS) was developed to validate the software-driven isocentric (SDI) approach to control the six-degrees-of-freedom movement of a robotic couch. Methods: The SDI approach to movements rotating around a predefined isocenter, referred to as a GeoIso, instead of a mechanical pivot point was developed by the robot automation industry. With robotic couch-sag corrections for weight load in a traditional SDI approach, movements could be accurately executed for a GeoIso located within a 500 mm cubic volume on the couch for treatments. The accuracy of SDI movement was investigated using the OTPS. The GeoIso was assumed to align with the proton beam isocenter (RadIso) for gantry at the reference angle. However, the misalignment between GeoIso and RadIso was quantitatively investigated by measuring the displacements at various couch angles for a target placed at the RadIso at an initial couch angle. When circular target displacements occur on a plane, a relative isocenter shift (RIS) correction could be applied in the SDI movement to minimize target displacements. Target displacements at a fixed gantry angle without and with RIS correction were measured for 12 robotic couches. Target displacements for various gantry angles were performed on three couches in gantry rooms to study the gantry-induced RadIso shift. The RIS correction can also be applied for the RadIso shift. A new SDI approach incorporating the RIS correction with the couch sag is described in this study. In parallel, the accuracy of SDI translation movements for various weight loads of patients on the couch was investigated during positioning of patients for proton prostate treatments. Results: For a fixed gantry angle, measured target displacements without RIS correction for couch rotations in the horizontal plane varied from 4 to 20 mm. However, measured displacements perpendicular to couch rotation plane were about 2 mm for all couches. Extracted

Utilization of optical tracking to validate a software-driven isocentric approach to robotic couch movements for proton radiotherapy

Energy Technology Data Exchange (ETDEWEB)

Hsi, Wen C., E-mail: Wen.Hsi@Mclaren.org, E-mail: Wenchien.hsi@sphic.org.cn; Zeidan, Omar A., E-mail: omar.zeidan@orlandohealth.com [ProCure Proton Therapy Center, Oklahoma City, Oklahoma 73142 (United States); Law, Aaron; Schreuder, Andreas N., E-mail: niek.schreuder@provisionhp.com [ProCure Training and Development Center, Bloomington, Indiana 47404 (United States)

2014-08-15

Purpose: An optical tracking and positioning system (OTPS) was developed to validate the software-driven isocentric (SDI) approach to control the six-degrees-of-freedom movement of a robotic couch. Methods: The SDI approach to movements rotating around a predefined isocenter, referred to as a GeoIso, instead of a mechanical pivot point was developed by the robot automation industry. With robotic couch-sag corrections for weight load in a traditional SDI approach, movements could be accurately executed for a GeoIso located within a 500 mm cubic volume on the couch for treatments. The accuracy of SDI movement was investigated using the OTPS. The GeoIso was assumed to align with the proton beam isocenter (RadIso) for gantry at the reference angle. However, the misalignment between GeoIso and RadIso was quantitatively investigated by measuring the displacements at various couch angles for a target placed at the RadIso at an initial couch angle. When circular target displacements occur on a plane, a relative isocenter shift (RIS) correction could be applied in the SDI movement to minimize target displacements. Target displacements at a fixed gantry angle without and with RIS correction were measured for 12 robotic couches. Target displacements for various gantry angles were performed on three couches in gantry rooms to study the gantry-induced RadIso shift. The RIS correction can also be applied for the RadIso shift. A new SDI approach incorporating the RIS correction with the couch sag is described in this study. In parallel, the accuracy of SDI translation movements for various weight loads of patients on the couch was investigated during positioning of patients for proton prostate treatments. Results: For a fixed gantry angle, measured target displacements without RIS correction for couch rotations in the horizontal plane varied from 4 to 20 mm. However, measured displacements perpendicular to couch rotation plane were about 2 mm for all couches. Extracted

Utilization of optical tracking to validate a software-driven isocentric approach to robotic couch movements for proton radiotherapy.

Science.gov (United States)

Hsi, Wen C; Law, Aaron; Schreuder, Andreas N; Zeidan, Omar A

2014-08-01

An optical tracking and positioning system (OTPS) was developed to validate the software-driven isocentric (SDI) approach to control the six-degrees-of-freedom movement of a robotic couch. The SDI approach to movements rotating around a predefined isocenter, referred to as a GeoIso, instead of a mechanical pivot point was developed by the robot automation industry. With robotic couch-sag corrections for weight load in a traditional SDI approach, movements could be accurately executed for a GeoIso located within a 500 mm cubic volume on the couch for treatments. The accuracy of SDI movement was investigated using the OTPS. The GeoIso was assumed to align with the proton beam isocenter (RadIso) for gantry at the reference angle. However, the misalignment between GeoIso and RadIso was quantitatively investigated by measuring the displacements at various couch angles for a target placed at the RadIso at an initial couch angle. When circular target displacements occur on a plane, a relative isocenter shift (RIS) correction could be applied in the SDI movement to minimize target displacements. Target displacements at a fixed gantry angle without and with RIS correction were measured for 12 robotic couches. Target displacements for various gantry angles were performed on three couches in gantry rooms to study the gantry-induced RadIso shift. The RIS correction can also be applied for the RadIso shift. A new SDI approach incorporating the RIS correction with the couch sag is described in this study. In parallel, the accuracy of SDI translation movements for various weight loads of patients on the couch was investigated during positioning of patients for proton prostate treatments. For a fixed gantry angle, measured target displacements without RIS correction for couch rotations in the horizontal plane varied from 4 to 20 mm. However, measured displacements perpendicular to couch rotation plane were about 2 mm for all couches. Extracted misalignments of GeoIso and RadIso in

Detection and correction of patient movement in prostate brachytherapy seed reconstruction

Science.gov (United States)

Lam, Steve T.; Cho, Paul S.; Marks, Robert J., II; Narayanan, Sreeram

2005-05-01

Intraoperative dosimetry of prostate brachytherapy can help optimize the dose distribution and potentially improve clinical outcome. Evaluation of dose distribution during the seed implant procedure requires the knowledge of 3D seed coordinates. Fluoroscopy-based seed localization is a viable option. From three x-ray projections obtained at different gantry angles, 3D seed positions can be determined. However, when local anaesthesia is used for prostate brachytherapy, the patient movement during fluoroscopy image capture becomes a practical problem. If uncorrected, the errors introduced by patient motion between image captures would cause seed mismatches. Subsequently, the seed reconstruction algorithm would either fail to reconstruct or yield erroneous results. We have developed an algorithm that permits detection and correction of patient movement that may occur between fluoroscopy image captures. The patient movement is decomposed into translational shifts along the tabletop and rotation about an axis perpendicular to the tabletop. The property of spatial invariance of the co-planar imaging geometry is used for lateral movement correction. Cranio-caudal movement is corrected by analysing the perspective invariance along the x-ray axis. Rotation is estimated by an iterative method. The method can detect and correct for the range of patient movement commonly seen in the clinical environment. The algorithm has been implemented for routine clinical use as the preprocessing step for seed reconstruction.

Dynamic Torque and Vertical Force Analysis during Nickel-titanium Rotary Root Canal Preparation with Different Modes of Reciprocal Rotation.

Science.gov (United States)

Tokita, Daisuke; Ebihara, Arata; Nishijo, Miki; Miyara, Kana; Okiji, Takashi

2017-10-01

The purpose of the present study was to compare 2 modes of reciprocal movement (torque-sensitive and time-dependent reciprocal rotation) with continuous rotation in terms of torque and apical force generation during nickel-titanium rotary root canal instrumentation. A custom-made automated root canal instrumentation and torque/force analyzing device was used to prepare simulated canals in resin blocks and monitor the torque and apical force generated in the blocks during preparation. Experimental groups (n = 7, each) consisted of (1) torque-sensitive reciprocal rotation with torque-sensitive vertical movement (group TqR), (2) time-dependent reciprocal rotation with time-dependent vertical movement (group TmR), and (3) continuous rotation with time-dependent vertical movement (group CR). The canals were instrumented with TF Adaptive SM1 and SM2 rotary files (SybronEndo, Orange, CA), and the torque and apical force were measured during instrumentation with SM2. The mean and maximum torque and apical force values were statistically analyzed using 1-way analysis of variance and the Tukey test (α = 0.05). The recordings showed intermittent increases of upward apical force and clockwise torque, indicating the generation and release of screw-in forces. The maximum upward apical force values in group TmR were significantly smaller than those in group CR (P forces when compared with continuous rotation. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Calibrated Tully-fisher Relations For Improved Photometric Estimates Of Disk Rotation Velocities

Science.gov (United States)

Reyes, Reinabelle; Mandelbaum, R.; Gunn, J. E.; Pizagno, J.

2011-01-01

We present calibrated scaling relations (also referred to as Tully-Fisher relations or TFRs) between rotation velocity and photometric quantities-- absolute magnitude, stellar mass, and synthetic magnitude (a linear combination of absolute magnitude and color)-- of disk galaxies at z 0.1. First, we selected a parent disk sample of 170,000 galaxies from SDSS DR7, with redshifts between 0.02 and 0.10 and r band absolute magnitudes between -18.0 and -22.5. Then, we constructed a child disk sample of 189 galaxies that span the parameter space-- in absolute magnitude, color, and disk size-- covered by the parent sample, and for which we have obtained kinematic data. Long-slit spectroscopy were obtained from the Dual Imaging Spectrograph (DIS) at the Apache Point Observatory 3.5 m for 99 galaxies, and from Pizagno et al. (2007) for 95 galaxies (five have repeat observations). We find the best photometric estimator of disk rotation velocity to be a synthetic magnitude with a color correction that is consistent with the Bell et al. (2003) color-based stellar mass ratio. The improved rotation velocity estimates have a wide range of scientific applications, and in particular, in combination with weak lensing measurements, they enable us to constrain the ratio of optical-to-virial velocity in disk galaxies.

Ampleness of head movements of children and adolescents with sensorineural hearing loss.

Science.gov (United States)

de Souza Melo, Renato

2017-02-01

Head movements are controlled by the vestibular system. Children with sensorineural hearing loss can present restrictions in ampleness of head movements due to damage in the vestibule-cochlear systems, resulting from injury in the inner ear. To evaluate the ampleness of head movements of children with normal hearing and children with sensorineural hearing loss and compare data between groups. Cross-sectional study that evaluated the ampleness of head movements of 96 students, being 48 with normal hearing and 48 with sensorineural hearing loss, of both sexes, with aged between 7 and 18 years old. The performance of ampleness of head movements was analyzed by a manual goniometric evaluation, according the references proposed by Marques. To the statistical analysis we used the t-Student test in case of normality of the data or the Mann-Whitney test when did not applied the suppositions of normality. Hearing loss children showed less mean in ampleness of all movements of head compared to normal hearing children, pointing difference to movements of flexion (p = 0,001), lateral inclination to the right (p = 0,025) and lateral rotation to the left (p = 0,021). Hearing loss children showed reduction in the ampleness of these head movements: flexion, lateral inclination to the right and lateral rotation to the left compared to normal hearing children. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Dynamic Effects of the Earth's Rotation Caused by the Annual and Semi-Annual Cyclic Mass Redistribution of the Planet

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M. Yu. Barkin

2016-01-01

Full Text Available The paper deals with development of the theory of perturbed rotational motion of a celestial body with variable geometry of the masses. Its main task is to study the impact of annual and semi-annual variations of the Earth's mass geometry (a component of its inertia tensor, as well as a component of its relative angular momentum, on the movement of the Earth's poles and its axial rotation. The body is considered to be a free (isolated, and the problem formulation corresponds to the classical Liouville problem on rotation of a variable body. Euler conical movement of the axially symmetric body with an arbitrary constant half-angle  is assumed as the unperturbed motion. In the classical theory of the Earth's rotation this angle is usually assumed to be zero.In the last 20 years, accuracy to determine the Earth rotation parameters owing to using methods of space geodesy and method of Very Long Baseline Interferometry (VLBI has increased by about three orders of magnitude and has made about  i.e., in angle measure it is about 10 - 20 arc-microseconds. According to experts, the theory of the Earth's rotation with such precision is not created yet. The paper is focused just on the new dynamic studies of the Earth rotation at a higher level of accuracy than has been done in previous studies, using a new approach to the problem, based on the new forms of the equations of motion (in the Andoyer variables and the analytical methods of perturbation theory (small parameter method.The problem of perturbed rotational motion with variable geometry and variable mass relative angular momentum in the first approximation is solved in Andoyer variables and projections of the angular velocity of the planet rotation. The analytical solution allows us to run applications to study dynamic effects from above factors for various bodies in the solar system, including the Earth. The solution allowed us to obtain the following parameters of the fundamental effects in the

Controlling of carrier movement on gamma irradiator ISG-500

International Nuclear Information System (INIS)

Achmad Suntoro

2010-01-01

Gamma irradiator ISG-500 is being designed. One of the design objects in the gamma irradiator is carrier movement and its controlling. Many possibilities of carrier movements can be implemented in the set-up design, such as using discrete or continuous mode. In this paper, selected discrete carriers movement and their controlling for the basic-design of the ISG-500 will be discussed. Nine stopper locations for nineteen carriers in operation will be controlled their carriers movement so that the movements have maximum positive transient load (increasing load) two carriers only. The controlling of the movement uses a train of pulses counting system as a one-dimension coordinate reference of a point on the rotated chain pulling the carrier. Every stopper location has a specific counting number in which will be used by the controlling system to let the carrier in the stopper location moving. By this movement, it is expected to prolong the life-time of the in use carrier mover motor. (author)

Nocturnal agitation in Huntington disease is caused by arousal-related abnormal movements rather than by rapid eye movement sleep behavior disorder.

Science.gov (United States)

Neutel, Dulce; Tchikviladzé, Maya; Charles, Perrine; Leu-Semenescu, Smaranda; Roze, Emmanuel; Durr, Alexandra; Arnulf, Isabelle

2015-06-01

Patients with Huntington disease (HD) and their spouses often complain of agitation during sleep, but the causes are mostly unknown. To evaluate sleep and nocturnal movements in patients with various HD stages and CAG repeats length. The clinical features and sleep studies of 29 patients with HD were retrospectively collected (11 referred for genotype-phenotype correlations and 18 for agitation during sleep) and compared with those of 29 age- and sex-matched healthy controls. All patients had videopolysomnography, but the movements during arousals were re-analyzed in six patients with HD with stored video. The patients had a longer total sleep period and REM sleep onset latency, but no other differences in sleep than controls. There was no correlation between CAG repeat length and sleep measures, but total sleep time and sleep efficiency were lower in the subgroup with moderate than milder form of HD. Periodic limb movements and REM sleep behavior disorders were excluded, although 2/29 patients had abnormal REM sleep without atonia. In contrast, they had clumsy and opisthotonos-like movements during arousals from non-REM or REM sleep. Some movements were violent and harmful. They might consist of voluntary movements inappropriately involving the proximal part of the limbs on a background of exaggerated hypotonia. Giant (>65 mcV) sleep spindles were observed in seven (24%) patients with HD and one control. The nocturnal agitation in patients with HD seems related to anosognostic voluntary movements on arousals, rather than to REM sleep behavior disorder and other sleep problems. Copyright © 2014 Elsevier B.V. All rights reserved.

THE H α EMISSION OF NEARBY M DWARFS AND ITS RELATION TO STELLAR ROTATION

International Nuclear Information System (INIS)

Newton, Elisabeth R.; Irwin, Jonathan; Charbonneau, David; Berlind, Perry; Calkins, Michael L.; Mink, Jessica

2017-01-01

The high-energy emission from low-mass stars is mediated by the magnetic dynamo. Although the mechanisms by which fully convective stars generate large-scale magnetic fields are not well understood, it is clear that, as for solar-type stars, stellar rotation plays a pivotal role. We present 270 new optical spectra of low-mass stars in the Solar Neighborhood. Combining our observations with those from the literature, our sample comprises 2202 measurements or non-detections of H α emission in nearby M dwarfs. This includes 466 with photometric rotation periods. Stars with masses between 0.1 and 0.6 M ⊙ are well-represented in our sample, with fast and slow rotators of all masses. We observe a threshold in the mass–period plane that separates active and inactive M dwarfs. The threshold coincides with the fast-period edge of the slowly rotating population, at approximately the rotation period at which an era of rapid rotational evolution appears to cease. The well-defined active/inactive boundary indicates that H α activity is a useful diagnostic for stellar rotation period, e.g., for target selection for exoplanet surveys, and we present a mass-period relation for inactive M dwarfs. We also find a significant, moderate correlation between L Hα / L bol and variability amplitude: more active stars display higher levels of photometric variability. Consistent with previous work, our data show that rapid rotators maintain a saturated value of L Hα / L bol . Our data also show a clear power-law decay in L Hα / L bol with Rossby number for slow rotators, with an index of −1.7 ± 0.1.

Induction of poloidal rotation by mean of a ponderomotive force

International Nuclear Information System (INIS)

Gutierrez T, C.; Martinell, J.

1999-01-01

When a plasma is radiated with a radiofrequency wave (RF) with fluxes of energy at hundred megawatts order (MW) the effect the of ponderomotive force (PM) is very important. This force applied to the plasma column can generate a rotation movement by a non-resonant mechanism. Particularly, it is known that the poloidal rotation can be induced by direct action of the PM force poloidal moment. This poloidal rotation of the plasma column can to explain the appearance of high confinement regime (H) in Tokamaks. In this work, it is analysed this mechanism, showing that if it is operated efficiently with the poloidal and parallel components of PM force then could be intensified the poloidal rotation moreover it is showed the form in which the asymptotic value of this rotation is established. (Author)

Effects of capture-related injury on postcapture movement of white-tailed deer.

Science.gov (United States)

Dechen Quinn, Amy C; Williams, David M; Porter, William F; Fitzgerald, Scott D; Hynes, Kevin

2014-04-01

Capture-related injuries or deaths of wildlife study subjects pose concerns to researchers, from considerations for animal welfare to inflated project costs and biased data. Capture myopathy (CM) is an injury that can affect an animal's survival ≤ 30 days postrelease, but is often difficult to detect without close monitoring and immediate necropsy. We evaluated the influence of capture and handling on postcapture movement in an attempt to characterize movement rates of animals suffering from CM. We captured and global positioning system-collared 95 white-tailed deer (Odocoileus virginianus) in central and northern New York during 2006-2008. Six juveniles died within 30 days postrelease, and necropsy reports indicated that two suffered CM (2%). We compared postcapture movement rates for juveniles that survived >30 days with those that died ≤ 30 days postcapture. Survivor movement rates (43.74 m/hr, SD = 3.53, n = 28) were significantly higher than rates for deer that died within 30 days (17.70 m/hr, SD = 1.57, n = 6) (Pheart rate, respiration rate) during handling between survivors and juveniles that died within 30 days postcapture but observed that survivors were in better body condition at capture. These results suggest that deer likely to die within the 30-day CM window can be identified soon after capture, provided that intensive movement data are collected. Further, even if necropsy reports are unavailable, these animals should be censored from analysis because their behavior is not representative of movements of surviving animals.

Effect of Putting Grip on Eye and Head Movements During the Golf Putting Stroke

Directory of Open Access Journals (Sweden)

George K. Hung

2003-01-01

Full Text Available The objective of this article is to determine the effect of three different putting grips (conventional, cross-hand, and one-handed on variations in eye and head movements during the putting stroke. Seven volunteer novice players, ranging in age from 21 to 22 years, participated in the study. During each experimental session, the subject stood on a specially designed platform covered with artificial turf and putted golf balls towards a standard golf hole. The three different types of grips were tested at two distances: 3 and 9 ft. For each condition, 20 putts were attempted. For each putt, data were recorded over a 3-s interval at a sampling rate of 100 Hz. Eye movements were recorded using a helmet-mounted eye movement monitor. Head rotation about an imaginary axis through the top of the head and its center-of-rotation was measured by means of a potentiometer mounted on a fixed frame and coupled to the helmet. Putter-head motion was measured using a linear array of infrared phototransistors embedded in the platform. The standard deviation (STD, relative to the initial level was calculated for eye and head movements over the duration of the putt (i.e., from the beginning of the backstroke, through the forward stroke, to impact. The averaged STD for the attempted putts was calculated for each subject. Then, the averaged STDs and other data for the seven subjects were statistically compared across the three grip conditions. The STD of eye movements were greater (p < 0.1 for conventional than cross-hand (9 ft and one-handed (3 and 9 ft grips. Also, the STD of head movements were greater (p < 0.1; 3 ft for conventional than cross-hand and one-handed grips. Vestibulo-ocular responses associated with head rotations could be observed in many 9 ft and some 3 ft putts. The duration of the putt was significantly longer (p < 0.05; 3 and 9 ft for the one-handed than conventional and cross-hand grips. Finally, performance, or percentage putts made, was

Postural Effects on the Mental Rotation of Body-Related Pictures: An fMRI Study

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Fangbing Qu

2018-05-01

Full Text Available This study investigated the embodied effects involved in the mental rotation of pictures of body parts (hands and feet. Blood oxygen level-dependent (BOLD signals were collected from 18 healthy volunteers who performed mental rotation tasks of rotated drawings of hands under different arm postures. Congruent drawings of hands (those congruent with left-hand posture evoked stronger activation in the left supplementary motor area (SMA, left precentral gyrus, and left superior parietal lobule (SPL than did incongruent drawings of hands. Congruent drawings of hands (those congruent with right-hand posture evoked significant activation in the left inferior parietal lobule (IPL, right SMA, bilateral middle frontal gyrus (MFG, left inferior frontal gyrus (IFG, and bilateral superior frontal gyrus (SFG compared to that evoked by the incongruent drawings of hands. Similar methodology was implemented with drawings of feet. However, no significant differences in brain activation were observed between congruent and incongruent drawings of feet. This finding suggests that body posture influences body part-related mental rotation in an effector-specific manner. A direct comparison between the medially and laterally rotated drawings revealed activation in the right IPL, left precentral gyrus, bilateral IFG, and bilateral SFG. These results suggest that biomechanical constraints affect the cognitive process of mental rotation.

Perceptual strategies of pigeons to detect a rotational centre--a hint for star compass learning?

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Bianca Alert

Full Text Available Birds can rely on a variety of cues for orientation during migration and homing. Celestial rotation provides the key information for the development of a functioning star and/or sun compass. This celestial compass seems to be the primary reference for calibrating the other orientation systems including the magnetic compass. Thus, detection of the celestial rotational axis is crucial for bird orientation. Here, we use operant conditioning to demonstrate that homing pigeons can principally learn to detect a rotational centre in a rotating dot pattern and we examine their behavioural response strategies in a series of experiments. Initially, most pigeons applied a strategy based on local stimulus information such as movement characteristics of single dots. One pigeon seemed to immediately ignore eccentric stationary dots. After special training, all pigeons could shift their attention to more global cues, which implies that pigeons can learn the concept of a rotational axis. In our experiments, the ability to precisely locate the rotational centre was strongly dependent on the rotational velocity of the dot pattern and it crashed at velocities that were still much faster than natural celestial rotation. We therefore suggest that the axis of the very slow, natural, celestial rotation could be perceived by birds through the movement itself, but that a time-delayed pattern comparison should also be considered as a very likely alternative strategy.

Rotation driven translational diffusion of polyatomic ions in water: A novel mechanism for breakdown of Stokes-Einstein relation

Science.gov (United States)

Banerjee, Puja; Yashonath, Subramanian; Bagchi, Biman

2017-04-01

While most of the existing theoretical and simulation studies have focused on simple, spherical, halide and alkali ions, many chemically, biologically, and industrially relevant electrolytes involve complex non-spherical polyatomic ions like nitrate, chlorate, and sulfate to name only a few. Interestingly, some polyatomic ions in spite of being larger in size show anomalously high diffusivity and therefore cause a breakdown of the venerable Stokes-Einstein (S-E) relation between the size and diffusivity. Here we report a detailed analysis of the dynamics of anions in aqueous potassium nitrate (KNO3) and aqueous potassium acetate (CH3COOK) solutions. The two ions, nitrate (-NO3) and acetate (CH3-CO2 ), with their similar size show a large difference in diffusivity values. We present evidence that the translational motion of these polyatomic ions is coupled to the rotational motion of the ion. We show that unlike the acetate ion, nitrate ion with a symmetric charge distribution among all periphery oxygen atoms shows a faster rotational motion with large amplitude rotational jumps which enhances its translational motion due to translational-rotational coupling. By creating a family of modified-charge model systems, we have analysed the rotational motion of asymmetric polyatomic ions and the contribution of it to the translational motion. These model systems help clarifying and establishing the relative contribution of rotational motion in enhancing the diffusivity of the nitrate ion over the value predicted by the S-E relation and also over the other polyatomic ions having asymmetric charge distribution like the acetate ion. In the latter case, reduced rotational motion results in lower diffusivity values than those with symmetric charge distribution. We propose translational-rotational coupling as a general mechanism of the breakdown of the S-E relation in the case of polyatomic ions.

Constraining eye movement in individuals with Parkinson's disease during walking turns.

Science.gov (United States)

Ambati, V N Pradeep; Saucedo, Fabricio; Murray, Nicholas G; Powell, Douglas W; Reed-Jones, Rebecca J

2016-10-01

Walking and turning is a movement that places individuals with Parkinson's disease (PD) at increased risk for fall-related injury. However, turning is an essential movement in activities of daily living, making up to 45 % of the total steps taken in a given day. Hypotheses regarding how turning is controlled suggest an essential role of anticipatory eye movements to provide feedforward information for body coordination. However, little research has investigated control of turning in individuals with PD with specific consideration for eye movements. The purpose of this study was to examine eye movement behavior and body segment coordination in individuals with PD during walking turns. Three experimental groups, a group of individuals with PD, a group of healthy young adults (YAC), and a group of healthy older adults (OAC), performed walking and turning tasks under two visual conditions: free gaze and fixed gaze. Whole-body motion capture and eye tracking characterized body segment coordination and eye movement behavior during walking trials. Statistical analysis revealed significant main effects of group (PD, YAC, and OAC) and visual condition (free and fixed gaze) on timing of segment rotation and horizontal eye movement. Within group comparisons, revealed timing of eye and head movement was significantly different between the free and fixed gaze conditions for YAC (p  0.05). In addition, while intersegment timings (reflecting segment coordination) were significantly different for YAC and OAC during free gaze (p training programs for those with PD, possibly promoting better coordination during turning and potentially reducing the risk of falls.

THE H α EMISSION OF NEARBY M DWARFS AND ITS RELATION TO STELLAR ROTATION

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Newton, Elisabeth R.; Irwin, Jonathan; Charbonneau, David; Berlind, Perry; Calkins, Michael L.; Mink, Jessica [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

2017-01-01

The high-energy emission from low-mass stars is mediated by the magnetic dynamo. Although the mechanisms by which fully convective stars generate large-scale magnetic fields are not well understood, it is clear that, as for solar-type stars, stellar rotation plays a pivotal role. We present 270 new optical spectra of low-mass stars in the Solar Neighborhood. Combining our observations with those from the literature, our sample comprises 2202 measurements or non-detections of H α emission in nearby M dwarfs. This includes 466 with photometric rotation periods. Stars with masses between 0.1 and 0.6 M {sub ⊙} are well-represented in our sample, with fast and slow rotators of all masses. We observe a threshold in the mass–period plane that separates active and inactive M dwarfs. The threshold coincides with the fast-period edge of the slowly rotating population, at approximately the rotation period at which an era of rapid rotational evolution appears to cease. The well-defined active/inactive boundary indicates that H α activity is a useful diagnostic for stellar rotation period, e.g., for target selection for exoplanet surveys, and we present a mass-period relation for inactive M dwarfs. We also find a significant, moderate correlation between L{sub Hα} / L{sub bol} and variability amplitude: more active stars display higher levels of photometric variability. Consistent with previous work, our data show that rapid rotators maintain a saturated value of L{sub Hα} / L {sub bol}. Our data also show a clear power-law decay in L{sub Hα} / L{sub bol} with Rossby number for slow rotators, with an index of −1.7 ± 0.1.

Kinematic relationship between rotation of lumbar spine and hip joints during golf swing in professional golfers.

Science.gov (United States)

Mun, Frederick; Suh, Seung Woo; Park, Hyun-Joon; Choi, Ahnryul

2015-05-14

Understanding the kinematics of the lumbar spine and hip joints during a golf swing is a basic step for identifying swing-specific factors associated with low back pain. The objective of this study was to examine the kinematic relationship between rotational movement of the lumbar spine and hip joints during a golf swing. Fifteen professional golfers participated in this study with employment of six infrared cameras to record their golf swings. Anatomical reference system of the upper torso, pelvis and thigh segments, and the location of each hip and knee joint were defined by the protocols of the kinematic model of previous studies. Lumbar spine and hip joint rotational angle was calculated utilizing the Euler angle method. Cross-correlation and angle-angle plot was used to examine the degree of kinematic relationship between joints. A fairly strong coupling relationship was shown between the lumbar spine and hip rotational movements with an average correlation of 0.81. Leading hip contribution to overall rotation was markedly high in the early stage of the downswing, while the lumbar spine contributed greater towards the end of the downswing; however, the relative contributions of the trailing hip and lumbar spine were nearly equal during the entire downswing. Most of the professional golfers participated in this study used a similar coordination strategy when moving their hips and lumbar spine during golf swings. The rotation of hips was observed to be more efficient in producing the overall rotation during the downswing when compared to the backswing. These results provide quantitative information to better understand the lumbar spine and hip joint kinematic characteristics of professional golfers. This study will have great potential to be used as a normal control data for the comparison with kinematic information among golfers with low back pain and for further investigation of golf swing-specific factors associated with injury.

The relationship between general measures of fitness, passive range of motion and whole-body movement quality.

Science.gov (United States)

Frost, David; Andersen, Jordan; Lam, Thomas; Finlay, Tim; Darby, Kevin; McGill, Stuart

2013-01-01

The goal of this study was to establish relationships between fitness (torso endurance, grip strength and pull-ups), hip range of motion (ROM) (extension, flexion, internal and external rotation) and movement quality in an occupational group with physical work demands. Fifty-three men from the emergency task force of a major city police force were investigated. The movement screen comprised standing and seated posture, gait, segmental spine motion and 14 tasks designed to challenge whole-body coordination. Relationships were established between each whole-body movement task, the measures of strength, endurance and ROM. In general, fitness and ROM were not strongly related to the movement quality of any task. This has implications for worker training, in that strategies developed to improve ROM or strength about a joint may not enhance movement quality. Worker-centered injury prevention can be described as fitting workers to tasks by improving fitness and modifying movement patterns; however, the current results show weak correlations between strength, endurance and ROM, and the way individuals move. Therefore, the development of occupation-specific injury prevention strategies may require both fitness and movement-oriented objectives.

Using visuo-kinetic virtual reality to induce illusory spinal movement: the MoOVi Illusion.

Science.gov (United States)

Harvie, Daniel S; Smith, Ross T; Hunter, Estin V; Davis, Miles G; Sterling, Michele; Moseley, G Lorimer

2017-01-01

Illusions that alter perception of the body provide novel opportunities to target brain-based contributions to problems such as persistent pain. One example of this, mirror therapy, uses vision to augment perceived movement of a painful limb to treat pain. Since mirrors can't be used to induce augmented neck or other spinal movement, we aimed to test whether such an illusion could be achieved using virtual reality, in advance of testing its potential therapeutic benefit. We hypothesised that perceived head rotation would depend on visually suggested movement. In a within-subjects repeated measures experiment, 24 healthy volunteers performed neck movements to 50 o of rotation, while a virtual reality system delivered corresponding visual feedback that was offset by a factor of 50%-200%-the Motor Offset Visual Illusion (MoOVi)-thus simulating more or less movement than that actually occurring. At 50 o of real-world head rotation, participants pointed in the direction that they perceived they were facing. The discrepancy between actual and perceived direction was measured and compared between conditions. The impact of including multisensory (auditory and visual) feedback, the presence of a virtual body reference, and the use of 360 o immersive virtual reality with and without three-dimensional properties, was also investigated. Perception of head movement was dependent on visual-kinaesthetic feedback ( p  = 0.001, partial eta squared = 0.17). That is, altered visual feedback caused a kinaesthetic drift in the direction of the visually suggested movement. The magnitude of the drift was not moderated by secondary variables such as the addition of illusory auditory feedback, the presence of a virtual body reference, or three-dimensionality of the scene. Virtual reality can be used to augment perceived movement and body position, such that one can perform a small movement, yet perceive a large one. The MoOVi technique tested here has clear potential for assessment and

Using visuo-kinetic virtual reality to induce illusory spinal movement: the MoOVi Illusion

Directory of Open Access Journals (Sweden)

Daniel S. Harvie

2017-02-01

Full Text Available Background Illusions that alter perception of the body provide novel opportunities to target brain-based contributions to problems such as persistent pain. One example of this, mirror therapy, uses vision to augment perceived movement of a painful limb to treat pain. Since mirrors can’t be used to induce augmented neck or other spinal movement, we aimed to test whether such an illusion could be achieved using virtual reality, in advance of testing its potential therapeutic benefit. We hypothesised that perceived head rotation would depend on visually suggested movement. Method In a within-subjects repeated measures experiment, 24 healthy volunteers performed neck movements to 50o of rotation, while a virtual reality system delivered corresponding visual feedback that was offset by a factor of 50%–200%—the Motor Offset Visual Illusion (MoOVi—thus simulating more or less movement than that actually occurring. At 50o of real-world head rotation, participants pointed in the direction that they perceived they were facing. The discrepancy between actual and perceived direction was measured and compared between conditions. The impact of including multisensory (auditory and visual feedback, the presence of a virtual body reference, and the use of 360o immersive virtual reality with and without three-dimensional properties, was also investigated. Results Perception of head movement was dependent on visual-kinaesthetic feedback (p = 0.001, partial eta squared = 0.17. That is, altered visual feedback caused a kinaesthetic drift in the direction of the visually suggested movement. The magnitude of the drift was not moderated by secondary variables such as the addition of illusory auditory feedback, the presence of a virtual body reference, or three-dimensionality of the scene. Discussion Virtual reality can be used to augment perceived movement and body position, such that one can perform a small movement, yet perceive a large one. The Mo

Droplet rotation model apply in steam uniform flow and gravitational field

International Nuclear Information System (INIS)

Zhang Jinyi; Bo Hanliang; Sun Yuliang; Wang Dazhong

2012-01-01

The mechanism droplet movement behavior and the qualitative description of droplet trajectory in the steam uniform flow field in the gravitational field were researched with droplet rotation model. According to the mechanism of gravitational field and uniform flow fields, the effects on droplets movement were analyzed and the importance of lift forces was also discussed. Finally, a general trajectory and mechanism of the droplets movement was derived which lays the groundwork for the qualitative analysis of the single-drop model and could be general enough to be used in many applications. (authors)

Monitoring current rates of salt dome movement

International Nuclear Information System (INIS)

Thoms, R.L.; Manning, T.A.

1977-01-01

The tectonic stability of salt domes is a major concern for long-term domal storage of noxious wastes. A necessary phase of the many faceted dome storage study includes obtaining a measure of current vertical movement of any potential storage dome. This information then can be combined with data obtained from studies involving geologic time scales so as to provide a history of dome movement that includes present time. A system of instrumentation for monitoring current rates of dome movement is described. Complimentary finite element modelling of plausible dome movement also is presented. The proposed instrumentation system includes tiltmeters, precise levelling, laser ranging, and monitoring of microseisms. Thus, components of rotation and vertical and horizontal movements at the ground surface over a dome can be monitored. In addition, a measure of dome movement also may be obtained acoustically. The finite element modelling furnishes an aid for: (1) locating instrument sites over a dome so as to maximize instrument sensitivity, and (2) interpreting data obtained from the instrumentation system. An example of tiltmeter installation and operation over a dome in northwest Louisiana is included. Typical tiltmeter output is presented and discussed

Six-strut arrangements for cartesian movements of mirrors

International Nuclear Information System (INIS)

Noll, T.; Zeschke, Th.; Reichardt, G.; Lammert, H.; Gudat, W.

2001-01-01

At BESSY a new six-strut arrangement for general small travel mirror adjustment mechanisms has been developed. This patented (Patent DE 10042802.5) arrangement allows very simple movements in all six linear and rotational degrees of freedom. The movements of the mirror are simply determined by moving either one drive, or up to three drives by the same amount. The first mirror adjustment systems of this design is successfully in operation since the start of BESSY II. Their performance and reliability is very satisfactory. This contribution will present the concepts

Functional Movement Disorder

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... Publications Patient Organizations International Parkinson and Movement Disorder Society National Institute of Mental Health (NIMH) See all related organizations Publications Order NINDS Publications Definition Psychogenic movement is an unwanted muscle movement such ...

[Study on spectrum analysis of X-ray based on rotational mass effect in special relativity].

Science.gov (United States)

Yu, Zhi-Qiang; Xie, Quan; Xiao, Qing-Quan

2010-04-01

Based on special relativity, the formation mechanism of characteristic X-ray has been studied, and the influence of rotational mass effect on X-ray spectrum has been given. A calculation formula of the X-ray wavelength based upon special relativity was derived. Error analysis was carried out systematically for the calculation values of characteristic wavelength, and the rules of relative error were obtained. It is shown that the values of the calculation are very close to the experimental values, and the effect of rotational mass effect on the characteristic wavelength becomes more evident as the atomic number increases. The result of the study has some reference meaning for the spectrum analysis of characteristic X-ray in application.

Dynamic visual acuity during transient and sinusoidal yaw rotation in normal and unilaterally vestibulopathic humans.

Science.gov (United States)

Tian, J R; Shubayev, I; Demer, J L

2001-03-01

The vestibulo-ocular reflex (VOR) stabilizes gaze to permit clear vision during head movements. It has been supposed that VOR function might be inferred from dynamic visual acuity (DVA), the acuity during imposed head motion. We sought to determine effectiveness of DVA for detection and lateralization of unilateral vestibulopathy, using rigorous psychophysical methods. Seventeen normal and 11 unilaterally vestibulopathic subjects underwent measurement of optically best corrected DVA during head motion. A variable size letter "E" 6 m distant was displayed in oblique random orientations to determine binocular DVA by a computer controlled, forced choice method. Three types of whole-body yaw rotation were delivered by a servo-controlled chair synchronized with optotype presentation. Two types of motion were predictable: (1) steady-state 2.0-Hz rotation at 10-130 degrees/s peak velocity with repetitive optotype presentation only during head velocity exceeding 80% of peak; and (2) directionally predictable transients at peak accelerations of 1000, 1600 and 2800 degrees/s2 with optotype presentation for 300 ms. For neither of these predictable motions did DVA in vestibulopathic subjects significantly differ from normal, with suggestions from search coil recordings that this was due to predictive slow and saccadic eye movements. Unilaterally vestibulopathic subjects experienced a significant decrease in DVA from the static condition during ipsilesional rotation for all three peak head accelerations. Only during directionally unpredictable transients with 75 ms or 300 ms optotype presentation was the sensitivity of DVA in unilaterally vestibulopathic subjects significantly abnormal during ipsilesional rotation. The ipsilesional decrease in DVA with head motion was greater for 75 ms than 300 ms optotype presentation. Search coil recordings confirmed hypometric compensatory eye movements during DVA testing with unpredictable, ipsilesional rotation. Receiver

Effect of spaceflight on the spatial orientation of the vestibulo-ocular reflex during eccentric roll rotation: A case report.

Science.gov (United States)

Reschke, Millard F; Wood, Scott J; Clément, Gilles

2018-01-01

Ground-based studies have reported shifts of the vestibulo-ocular reflex (VOR) slow phase velocity (SPV) axis toward the resultant gravito-inertial force vector. The VOR was examined during eccentric roll rotation before, during and after an 8-day orbital mission. On orbit this vector is aligned with the head z-axis. Our hypothesis was that eccentric roll rotation on orbit would generate horizontal eye movements. Two subjects were rotated in a semi-supine position with the head nasal-occipital axis parallel to the axis of rotation and 0.5 m off-center. The chair accelerated at 120 deg/s2 to 120 deg/s, rotated at constant velocity for one minute, and then decelerated to a stop in similar fashion. On Earth, the stimulation primarily generated torsional VOR. During spaceflight, in one subject torsional VOR became horizontal VOR, and then decayed very slowly. In the other subject, torsional VOR was reduced on orbit relative to pre- and post-flight, but the SPV axis did not rotate. We attribute the shift from torsional to horizontal VOR on orbit to a spatial orientation of velocity storage toward alignment with the gravito-inertial force vector, and the inter-individual difference to cognitive factors related to the subjective straight-ahead.

Effects of kinesthetic versus visual imagery practice on two technical dance movements: a pilot study.

Science.gov (United States)

Girón, Elizabeth Coker; McIsaac, Tara; Nilsen, Dawn

2012-03-01

Motor imagery is a type of mental practice that involves imagining the body performing a movement in the absence of motor output. Dance training traditionally incorporates mental practice techniques, but quantitative effects of motor imagery on the performance of dance movements are largely unknown. This pilot study compared the effects of two different imagery modalities, external visual imagery and kinesthetic imagery, on pelvis and hip kinematics during two technical dance movements, plié and sauté. Each of three female dance students (mean age = 19.7 years, mean years of training = 10.7) was assigned to use a type of imagery practice: visual imagery, kinesthetic imagery, or no imagery. Effects of motor imagery on peak external hip rotation varied by both modality and task. Kinesthetic imagery increased peak external hip rotation for pliés, while visual imagery increased peak external hip rotation for sautés. Findings suggest that the success of motor imagery in improving performance may be task-specific. Dancers may benefit from matching imagery modality to technical tasks in order to improve alignment and thereby avoid chronic injury.

Simultaneous Detection of Displacement, Rotation Angle, and Contact Pressure Using Sandpaper Molded Elastomer Based Triple Electrode Sensor.

Science.gov (United States)

Choi, Eunsuk; Sul, Onejae; Lee, Seung-Beck

2017-09-06

In this article, we report on a flexible sensor based on a sandpaper molded elastomer that simultaneously detects planar displacement, rotation angle, and vertical contact pressure. When displacement, rotation, and contact pressure are applied, the contact area between the translating top elastomer electrode and the stationary three bottom electrodes change characteristically depending on the movement, making it possible to distinguish between them. The sandpaper molded undulating surface of the elastomer reduces friction at the contact allowing the sensor not to affect the movement during measurement. The sensor showed a 0.25 mm −1 displacement sensitivity with a ±33 μm accuracy, a 0.027 degree −1 of rotation sensitivity with ~0.95 degree accuracy, and a 4.96 kP −1 of pressure sensitivity. For possible application to joint movement detection, we demonstrated that our sensor effectively detected the up-and-down motion of a human forefinger and the bending and straightening motion of a human arm.

Ground-penetrating radar observations for estimating the vertical displacement of rotational landslides

OpenAIRE

C. Lissak; O. Maquaire; J.-P. Malet; F. Lavigne; C. Virmoux; C. Gomez; R. Davidson

2014-01-01

The objective of this paper is to demonstrate the applicability of Ground Penetrating Radar (GPR) for monitoring the displacement of slow-moving landslides. GPR data is used to estimate the vertical movement of rotational slides in combination with other surveying techniques. The experimental site is located along the Normandy coast (North East France) here several rotational landslides are continuously affected by a seasonal kinematic pattern (low displacem...

Rotational and frictional dynamics of the slamming of a door

Science.gov (United States)

Klein, Pascal; Müller, Andreas; Gröber, Sebastian; Molz, Alexander; Kuhn, Jochen

2017-01-01

A theoretical and experimental investigation of the rotational dynamics, including friction, of a slamming door is presented. Based on existing work regarding different damping models for rotational and oscillatory motions, we examine different forms for the (angular) velocity dependence (ωn, n = 0, 1, 2) of the frictional force. An analytic solution is given when all three friction terms are present and several solutions for specific cases known from the literature are reproduced. The motion of a door is investigated experimentally using a smartphone, and the data are compared with the theoretical results. A laboratory experiment under more controlled conditions is conducted to gain a deeper understanding of the movement of a slammed door. Our findings provide quantitative evidence that damping models involving quadratic air drag are most appropriate for the slamming of a door. Examining this everyday example of a physical phenomenon increases student motivation, because they can relate it to their own personal experience.

Vestibular feedback maintains reaching accuracy during body movement

Science.gov (United States)

Reynolds, Raymond F.

2016-01-01

Key points Reaching movements can be perturbed by vestibular input, but the function of this response is unclear.Here, we applied galvanic vestibular stimulation concurrently with real body movement while subjects maintained arm position either fixed in space or fixed with respect to their body.During the fixed‐in‐space conditions, galvanic vestibular stimulation caused large changes in arm trajectory consistent with a compensatory response to maintain upper‐limb accuracy in the face of body movement.Galvanic vestibular stimulation responses were absent during the body‐fixed task, demonstrating task dependency in vestibular control of the upper limb.The results suggest that the function of vestibular‐evoked arm movements is to maintain the accuracy of the upper limb during unpredictable body movement, but only when reaching in an earth‐fixed reference frame. Abstract When using our arms to interact with the world, unintended body motion can introduce movement error. A mechanism that could detect and compensate for such motion would be beneficial. Observations of arm movements evoked by vestibular stimulation provide some support for this mechanism. However, the physiological function underlying these artificially evoked movements is unclear from previous research. For such a mechanism to be functional, it should operate only when the arm is being controlled in an earth‐fixed rather than a body‐fixed reference frame. In the latter case, compensation would be unnecessary and even deleterious. To test this hypothesis, subjects were gently rotated in a chair while being asked to maintain their outstretched arm pointing towards either earth‐fixed or body‐fixed memorized targets. Galvanic vestibular stimulation was applied concurrently during rotation to isolate the influence of vestibular input, uncontaminated by inertial factors. During the earth‐fixed task, galvanic vestibular stimulation produced large polarity‐dependent corrections in arm

The Sense of Agency Is More Sensitive to Manipulations of Outcome than Movement-Related Feedback Irrespective of Sensory Modality.

Directory of Open Access Journals (Sweden)

Nicole David

Full Text Available The sense of agency describes the ability to experience oneself as the agent of one's own actions. Previous studies of the sense of agency manipulated the predicted sensory feedback related either to movement execution or to the movement's outcome, for example by delaying the movement of a virtual hand or the onset of a tone that resulted from a button press. Such temporal sensorimotor discrepancies reduce the sense of agency. It remains unclear whether movement-related feedback is processed differently than outcome-related feedback in terms of agency experience, especially if these types of feedback differ with respect to sensory modality. We employed a mixed-reality setup, in which participants tracked their finger movements by means of a virtual hand. They performed a single tap, which elicited a sound. The temporal contingency between the participants' finger movements and (i the movement of the virtual hand or (ii the expected auditory outcome was systematically varied. In a visual control experiment, the tap elicited a visual outcome. For each feedback type and participant, changes in the sense of agency were quantified using a forced-choice paradigm and the Method of Constant Stimuli. Participants were more sensitive to delays of outcome than to delays of movement execution. This effect was very similar for visual or auditory outcome delays. Our results indicate different contributions of movement- versus outcome-related sensory feedback to the sense of agency, irrespective of the modality of the outcome. We propose that this differential sensitivity reflects the behavioral importance of assessing authorship of the outcome of an action.

Head movement during CT brain perfusion acquisition of patients with suspected acute ischemic stroke

International Nuclear Information System (INIS)

Fahmi, F.; Beenen, L.F.M.; Streekstra, G.J.; Janssen, N.Y.; Jong, H.W. de; Riordan, A.; Roos, Y.B.; Majoie, C.B.; Bavel, E. van; Marquering, H.A.

2013-01-01

Objective: Computed Tomography Perfusion (CTP) is a promising tool to support treatment decision for acute ischemic stroke patients. However, head movement during acquisition may limit its applicability. Information of the extent of head motion is currently lacking. Our purpose is to qualitatively and quantitatively assess the extent of head movement during acquisition. Methods: From 103 consecutive patients admitted with suspicion of acute ischemic stroke, head movement in 220 CTP datasets was qualitatively categorized by experts as none, minimal, moderate, or severe. The movement was quantified using 3D registration of CTP volume data with non-contrast CT of the same patient; yielding 6 movement parameters for each time frame. The movement categorization was correlated with National Institutes of Health Stroke Scale (NIHSS) score and baseline characteristic using multinomial logistic regression and student's t-test respectively. Results: Moderate and severe head movement occurred in almost 25% (25/103) of all patients with acute ischemic stroke. The registration technique quantified head movement with mean rotation angle up to 3.6° and 14°, and mean translation up to 9.1 mm and 22.6 mm for datasets classified as moderate and severe respectively. The rotation was predominantly in the axial plane (yaw) and the main translation was in the scan direction. There was no statistically significant association between movement classification and NIHSS score and baseline characteristics. Conclusions: Moderate or severe head movement during CTP acquisition of acute stroke patients is quite common. The presented registration technique can be used to automatically quantify the movement during acquisition, which can assist identification of CTP datasets with excessive head movement

Head movement during CT brain perfusion acquisition of patients with suspected acute ischemic stroke

Energy Technology Data Exchange (ETDEWEB)

Fahmi, F., E-mail: f.fahmi@amc.uva.nl [Department of Biomedical Engineering and Physics, AMC, Amsterdam (Netherlands); Beenen, L.F.M., E-mail: l.f.beenen@amc.uva.nl [Department of Radiology, AMC, Amsterdam (Netherlands); Streekstra, G.J., E-mail: g.j.streekstra@amc.uva.nl [Department of Biomedical Engineering and Physics, AMC, Amsterdam (Netherlands); Janssen, N.Y., E-mail: n.n.janssen@amc.uva.nl [Department of Biomedical Engineering and Physics, AMC, Amsterdam (Netherlands); Jong, H.W. de, E-mail: H.W.A.M.deJong@umcutrecht.nl [Department of Radiology, UMC Utrecht, 3584CX, Utrecht (Netherlands); Riordan, A., E-mail: alan.riordan@gmail.com [Department of Radiology, UMC Utrecht, 3584CX, Utrecht (Netherlands); Roos, Y.B., E-mail: y.b.roos@amc.uva.nl [Department of Neurology, AMC, Amsterdam (Netherlands); Majoie, C.B., E-mail: c.b.majoie@amc.uva.nl [Department of Radiology, AMC, Amsterdam (Netherlands); Bavel, E. van, E-mail: e.vanbavel@amc.uva.nl [Department of Biomedical Engineering and Physics, AMC, Amsterdam (Netherlands); Marquering, H.A., E-mail: h.a.marquering@amc.uva.nl [Department of Biomedical Engineering and Physics, AMC, Amsterdam (Netherlands); Department of Radiology, AMC, Amsterdam (Netherlands)

2013-12-01

Objective: Computed Tomography Perfusion (CTP) is a promising tool to support treatment decision for acute ischemic stroke patients. However, head movement during acquisition may limit its applicability. Information of the extent of head motion is currently lacking. Our purpose is to qualitatively and quantitatively assess the extent of head movement during acquisition. Methods: From 103 consecutive patients admitted with suspicion of acute ischemic stroke, head movement in 220 CTP datasets was qualitatively categorized by experts as none, minimal, moderate, or severe. The movement was quantified using 3D registration of CTP volume data with non-contrast CT of the same patient; yielding 6 movement parameters for each time frame. The movement categorization was correlated with National Institutes of Health Stroke Scale (NIHSS) score and baseline characteristic using multinomial logistic regression and student's t-test respectively. Results: Moderate and severe head movement occurred in almost 25% (25/103) of all patients with acute ischemic stroke. The registration technique quantified head movement with mean rotation angle up to 3.6° and 14°, and mean translation up to 9.1 mm and 22.6 mm for datasets classified as moderate and severe respectively. The rotation was predominantly in the axial plane (yaw) and the main translation was in the scan direction. There was no statistically significant association between movement classification and NIHSS score and baseline characteristics. Conclusions: Moderate or severe head movement during CTP acquisition of acute stroke patients is quite common. The presented registration technique can be used to automatically quantify the movement during acquisition, which can assist identification of CTP datasets with excessive head movement.

Possible relation between pulsar rotation and evolution of magnetic inclination

Science.gov (United States)

Tian, Jun

2018-05-01

The pulsar timing is observed to be different from predicted by a simple magnetic dipole radiation. We choose eight pulsars whose braking index was reliably determined. Assuming the smaller values of braking index are dominated by the secular evolution of the magnetic inclination, we calculate the increasing rate of the magnetic inclination for each pulsar. We find a possible relation between the rotation frequency of each pulsar and the inferred evolution of the magnetic inclination. Due to the model-dependent fit of the magnetic inclination and other effects, more observational indicators for the change rate of magnetic inclination are needed to test the relation.

Chunk concatenation evolves with practice and sleep-related enhancement consolidation in a complex arm movement sequence

Directory of Open Access Journals (Sweden)

Blischke Klaus

2016-06-01

Full Text Available This paper addresses the notion of chunk concatenation being associated with sleep-related enhancement consolidation of motor sequence memory, thereby essentially contributing to improvements in sequence execution speed. To this end, element movement times of a multi-joint arm movement sequence incorporated in a recent study by Malangré et al. (2014 were reanalyzed. As sequence elements differed with respect to movement distance, element movement times had to be purged from differences solely due to varying trajectory lengths. This was done by dividing each element movement time per subject and trial block by the respective “reference movement time” collected from subjects who had extensively practiced each sequence element in isolation. Any differences in these “relative element movement times” were supposed to reflect element-specific “production costs” imposed solely by the sequence context. Across all subjects non-idiosyncratic, lasting sequence segmentation was shown, and four possible concatenation points (i.e. transition points between successive chunks within the original arm movement sequence were identified. Based on theoretical suppositions derived from previous work with the discrete sequence production task and the dual processor model (Abrahamse et al., 2013, significantly larger improvements in transition speed occurring at these four concatenation points as compared to the five fastest transition positions within the sequence (associated with mere element execution were assumed to indicate increased chunk concatenation. As a result, chunk concatenation was shown to proceed during acquisition with physical practice, and, most importantly, to significantly progress some more during retention following a night of sleep, but not during a waking interval.

Athletic groin pain (part 2): a prospective cohort study on the biomechanical evaluation of change of direction identifies three clusters of movement patterns

Science.gov (United States)

Franklyn-Miller, A; Richter, C; King, E; Gore, S; Moran, K; Strike, S; Falvey, E C

2017-01-01

Background Athletic groin pain (AGP) is prevalent in sports involving repeated accelerations, decelerations, kicking and change-of-direction movements. Clinical and radiological examinations lack the ability to assess pathomechanics of AGP, but three-dimensional biomechanical movement analysis may be an important innovation. Aim The primary aim was to describe and analyse movements used by patients with AGP during a maximum effort change-of-direction task. The secondary aim was to determine if specific anatomical diagnoses were related to a distinct movement strategy. Methods 322 athletes with a current symptom of chronic AGP participated. Structured and standardised clinical assessments and radiological examinations were performed on all participants. Additionally, each participant performed multiple repetitions of a planned maximum effort change-of-direction task during which whole body kinematics were recorded. Kinematic and kinetic data were examined using continuous waveform analysis techniques in combination with a subgroup design that used gap statistic and hierarchical clustering. Results Three subgroups (clusters) were identified. Kinematic and kinetic measures of the clusters differed strongly in patterns observed in thorax, pelvis, hip, knee and ankle. Cluster 1 (40%) was characterised by increased ankle eversion, external rotation and knee internal rotation and greater knee work. Cluster 2 (15%) was characterised by increased hip flexion, pelvis contralateral drop, thorax tilt and increased hip work. Cluster 3 (45%) was characterised by high ankle dorsiflexion, thorax contralateral drop, ankle work and prolonged ground contact time. No correlation was observed between movement clusters and clinically palpated location of the participant's pain. Conclusions We identified three distinct movement strategies among athletes with long-standing groin pain during a maximum effort change-of-direction task These movement strategies were not related to clinical

Adaptive autoregressive identification with spectral power decomposition for studying movement-related activity in scalp EEG signals and basal ganglia local field potentials

Science.gov (United States)

Foffani, Guglielmo; Bianchi, Anna M.; Priori, Alberto; Baselli, Giuseppe

2004-09-01

We propose a method that combines adaptive autoregressive (AAR) identification and spectral power decomposition for the study of movement-related spectral changes in scalp EEG signals and basal ganglia local field potentials (LFPs). This approach introduces the concept of movement-related poles, allowing one to study not only the classical event-related desynchronizations (ERD) and synchronizations (ERS), which correspond to modulations of power, but also event-related modulations of frequency. We applied the method to analyze movement-related EEG signals and LFPs contemporarily recorded from the sensorimotor cortex, the globus pallidus internus (GPi) and the subthalamic nucleus (STN) in a patient with Parkinson's disease who underwent stereotactic neurosurgery for the implant of deep brain stimulation (DBS) electrodes. In the AAR identification we compared the whale and the exponential forgetting factors, showing that the whale forgetting provides a better disturbance rejection and it is therefore more suitable to investigate movement-related brain activity. Movement-related power modulations were consistent with previous studies. In addition, movement-related frequency modulations were observed from both scalp EEG signals and basal ganglia LFPs. The method therefore represents an effective approach to the study of movement-related brain activity.

Objective classification of scapular kinematics in participants with movement faults of the scapula on clinical assessment.

Science.gov (United States)

Warner, Martin B; Whatling, Gemma; Worsley, Peter R; Mottram, Sarah; Chappell, Paul H; Holt, Catherine A; Stokes, Maria J

2015-01-01

The aim of this study was to assess the potential of employing a classification tool to objectively classify participants with clinically assessed movement faults (MFs) of the scapula. Six participants with a history of shoulder pain with MFs of the scapula and 12 healthy participants with no movement faults (NMFs) performed a flexion movement control test of the scapula, while scapular kinematic data were collected. Principal component scores and discrete kinematic variables were used as input into a classifier. Five out of the six participants with a history of pain were successfully classified as having scapular MFs with an accuracy of 72%. Variables related to the upward rotation of the scapula had the most influence on the classification. The results of the study demonstrate the potential of adopting a multivariate approach in objective classification of participants with altered scapular kinematics in pathological groups.

Magnetometer and Gyroscope Calibration Method with Level Rotation

Directory of Open Access Journals (Sweden)

Zongkai Wu

2018-03-01

Full Text Available Micro electro mechanical system (MEMS gyroscopes and magnetometers are usually integrated into a sensor module or chip and widely used in a variety of applications. In existing integrated gyroscope and magnetometer calibration methods, rotation in all possible orientations is a necessary condition for a good calibration result. However, rotation around two or more axes is difficult to attain, as it is limited by the range of movement of vehicles such as cars, ships, or planes. To solve this problem, this paper proposes an integrated magnetometer and gyroscope calibration method with level rotation. The proposed method presents a redefined magnetometer output model using level attitude. New gyroscope and magnetometer calibration models are then deduced. In addition, a simplified cubature Kalman filter (CKF is established to estimate calibration parameters. This method possesses important value for application in actual systems, as it only needs level rotation for real-time calibration of gyroscopes and magnetometers. Theoretical analysis and test results verify the validity and feasibility of this method.

Gravitational wave content and stability of uniformly, rotating, triaxial neutron stars in general relativity.

Science.gov (United States)

Tsokaros, Antonios; Ruiz, Milton; Paschalidis, Vasileios; Shapiro, Stuart L; Baiotti, Luca; Uryū, Kōji

2017-06-15

Targets for ground-based gravitational wave interferometers include continuous, quasiperiodic sources of gravitational radiation, such as isolated, spinning neutron stars. In this work, we perform evolution simulations of uniformly rotating, triaxially deformed stars, the compressible analogs in general relativity of incompressible, Newtonian Jacobi ellipsoids. We investigate their stability and gravitational wave emission. We employ five models, both normal and supramassive, and track their evolution with different grid setups and resolutions, as well as with two different evolution codes. We find that all models are dynamically stable and produce a strain that is approximately one-tenth the average value of a merging binary system. We track their secular evolution and find that all our stars evolve toward axisymmetry, maintaining their uniform rotation, rotational kinetic energy, and angular momentum profiles while losing their triaxiality.

Rotation sequence to report humerothoracic kinematics during 3D motion involving large horizontal component: application to the tennis forehand drive.

Science.gov (United States)

Creveaux, Thomas; Sevrez, Violaine; Dumas, Raphaël; Chèze, Laurence; Rogowski, Isabelle

2018-03-01

The aim of this study was to examine the respective aptitudes of three rotation sequences (Y t X f 'Y h '', Z t X f 'Y h '', and X t Z f 'Y h '') to effectively describe the orientation of the humerus relative to the thorax during a movement involving a large horizontal abduction/adduction component: the tennis forehand drive. An optoelectronic system was used to record the movements of eight elite male players, each performing ten forehand drives. The occurrences of gimbal lock, phase angle discontinuity and incoherency in the time course of the three angles defining humerothoracic rotation were examined for each rotation sequence. Our results demonstrated that no single sequence effectively describes humerothoracic motion without discontinuities throughout the forehand motion. The humerothoracic joint angles can nevertheless be described without singularities when considering the backswing/forward-swing and the follow-through phases separately. Our findings stress that the sequence choice may have implications for the report and interpretation of 3D joint kinematics during large shoulder range of motion. Consequently, the use of Euler/Cardan angles to represent 3D orientation of the humerothoracic joint in sport tasks requires the evaluation of the rotation sequence regarding singularity occurrence before analysing the kinematic data, especially when the task involves a large shoulder range of motion in the horizontal plane.

Ultrahigh enhancement in absolute and relative rotation sensing using fast and slow light

International Nuclear Information System (INIS)

Shahriar, M. S.; Pati, G. S.; Tripathi, R.; Gopal, V.; Messall, M.; Salit, K.

2007-01-01

We describe a resonator-based optical gyroscope whose sensitivity for measuring absolute rotation is enhanced via use of the anomalous dispersion characteristic of superluminal light propagation. The enhancement is given by the inverse of the group index, saturating to a bound determined by the group velocity dispersion. We also show how the offsetting effect of the concomitant broadening of the resonator linewidth may be circumvented by using an active cavity. For realistic conditions, the enhancement factor is as high as 10 6 . We also show how normal dispersion used for slow light can enhance relative rotation sensing in a specially designed Sagnac interferometer, with the enhancement given by the slowing factor

Rotational motion in nuclei

International Nuclear Information System (INIS)

Bohr, A.

1977-01-01

History is surveyed of the development of the theory of rotational states in nuclei. The situation in the 40's when ideas formed of the collective states of a nucleus is evoked. The general rotation theory and the relation between the single-particle and rotational motion are briefly discussed. Future prospects of the rotation theory development are indicated. (I.W.)

Comparison of the Event-Related Desynchronization during Self-Paced Movement and when playing a Nintendo Wii Game

Directory of Open Access Journals (Sweden)

Nikola Šobajić

2011-06-01

Full Text Available We compared pre-movement event-related desynchronization (ERD of μ rhythm over the primary motor cortex using surface electrodes in a group of five healthy subjects during self-paced wrist movement and the wrist movement when playing a Nintendo Wii. We present a method that uses ERD to detect the onset of movement in single-trial electroencephalographic (EEG data. This algorithm produced a mean detection accuracy of 83% for the self-paced movement and 75% for the Wii-included sessions, without requiring subject training. This technique can be employed in an EEG-based brain–computer interface due to its high recognition rate and simplicity in computation.

Movements in the sacroiliac joints demonstrated with roentgen stereophotogrammetry

International Nuclear Information System (INIS)

Egund, N.; Olsson, T.H.; Schmid, H.; Selvik, G.

1978-01-01

Using a roentgen stereophotogrammetric method, the three-dimensional movements in the sacroiliac joints were quantified in 4 patients. To provoke motion of the sacrum, changes between body positions and a test with manual pressure were used. In tests with symmetric forces on the sacrum, it in most cases rotated mainly about a transverse axis and at most approximately 2 0 . The axis of rotation passed through the iliac bones mainly in the lower part of the iliac tuberosity. The rotations between the iliac bones and the sacrum about any of the three main axes were determined with a precision in the mean of 0.2 0 . The distance between the two superior posterior iliac spines varied at most 0.4 mm between seven different body positions. (Auth.)

Self-motion perception and vestibulo-ocular reflex during whole body yaw rotation in standing subjects: the role of head position and neck proprioception.

Science.gov (United States)

Panichi, Roberto; Botti, Fabio Massimo; Ferraresi, Aldo; Faralli, Mario; Kyriakareli, Artemis; Schieppati, Marco; Pettorossi, Vito Enrico

2011-04-01

Self-motion perception and vestibulo-ocular reflex (VOR) were studied during whole body yaw rotation in the dark at different static head positions. Rotations consisted of four cycles of symmetric sinusoidal and asymmetric oscillations. Self-motion perception was evaluated by measuring the ability of subjects to manually track a static remembered target. VOR was recorded separately and the slow phase eye position (SPEP) was computed. Three different head static yaw deviations (active and passive) relative to the trunk (0°, 45° to right and 45° to left) were examined. Active head deviations had a significant effect during asymmetric oscillation: the movement perception was enhanced when the head was kept turned toward the side of body rotation and decreased in the opposite direction. Conversely, passive head deviations had no effect on movement perception. Further, vibration (100 Hz) of the neck muscles splenius capitis and sternocleidomastoideus remarkably influenced perceived rotation during asymmetric oscillation. On the other hand, SPEP of VOR was modulated by active head deviation, but was not influenced by neck muscle vibration. Through its effects on motion perception and reflex gain, head position improved gaze stability and enhanced self-motion perception in the direction of the head deviation. Copyright © 2010 Elsevier B.V. All rights reserved.

Testing of the line element of special relativity with rotating systems

Science.gov (United States)

Vargas, Jose G.; Torr, Douglas G.

1989-01-01

Experiments with rotating systems are examined from the point of view of a test theory of the Lorentz transformations (LTs), permitting, in principle, the verification of the simultaneity relation. The significance of the experiments involved in the testing of the LTs can be determined using Robertson's test theory (RTT). A revised RTT is discussed, and attention is given to the Ehrenfest paradox in connection with the testing of the LTs.

Humeral retroversion and shoulder rotational mobility in young handball practitioners.

Science.gov (United States)

Quadros, Gustavo Aguiar; Döhnert, Marcelo Baptista

2015-01-01

: To evaluate the prevalence of humeral retroversion and rotational mobility (RHH) in young handball practitioners and non-practitioners. : This is a cross-sectional study performed with two groups: the handball group, with 14 female students practicing handball and the control group, with 13 young participants non-practicing pitch sports. : The handball group presented full rotational movement (FRM) hi-gher than the control group in both the dominant shoulder (p=0.001) and the non-dominant shoulder (p=0.0001). The mobility of active and passive internal rotation was significantly higher in handball players in both shoulders. The handball group presented lower internal rotation range of motion for the dominant shoulder as compared to the non-dominant shoul-der (p=0.001). : Young handball practitioners, des-pite skeletally immature, showed a higher MRT than the control group. The handball group showed loss of internal rotation (medial) on the dominant shoulder as compared to the non--dominant shoulder. Level of Evidence II, Prospective Study.

Six-degree-of-freedom near-source seismic motions I: rotation-to-translation relations and synthetic examples

Czech Academy of Sciences Publication Activity Database

Brokešová, J.; Málek, Jiří

2015-01-01

Roč. 19, č. 2 (2015), s. 491-509 ISSN 1383-4649 R&D Projects: GA ČR GAP210/10/0925; GA MŠk LM2010008; GA ČR GA15-02363S Institutional support: RVO:67985891 Keywords : seismic rotation * near-source region * rotation-to-translation relations * numerical simulations * S-wave velocity Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 1.550, year: 2015

Higher plantar pressure on the medial side in four soccer-related movements.

Science.gov (United States)

Wong, Pui-lam; Chamari, Karim; Mao, De Wei; Wisløff, Ulrik; Hong, Youlian

2007-02-01

To measure the plantar pressure in four soccer-related movements in 15 male soccer players (mean (SD) age 20.9 (1.3) years, height 173 (4) cm, weight 61.7 (3.6) kg). To record plantar pressure distribution, the players wore soccer boots with 12 circular studs and with an insole pressure recorder device equipped with 99 sensors. Plantar pressure was recorded in five successful trials in each of the four soccer-related movements: running, sideward cutting, 45 degrees cutting and landing from a vertical jump. Each footprint was divided into 10 recorded areas for analysis. Compared with running at 3.3 m/s, maximal speed sideward cutting and 45 degrees cutting induced higher peak pressure (pplantar surface as compared with the lateral side. These data suggest that the medial side of the plantar surface may be more prone to injuries, and that foot orthosis adoption, improved soccer boot design and specific muscle training could be considered to reduce pressure and the subsequent risk of injury.

Relative mobility of the pelvis and spine during trunk axial rotation in chronic low back pain patients: A case-control study.

Directory of Open Access Journals (Sweden)

Masashi Taniguchi

Full Text Available Trunk axial rotation is a risk factor for chronic low back pain (CLBP. The characteristics of rotational mobility in the pelvis and spine among CLBP patients are not fully understood.The purpose of this study was to examine three-dimensional kinematic changes, and to compare the differences of rotational mobility and coupled motion, in patients with and without CLBP.Fifteen patients with CLBP and 15 age and sex matched healthy subjects participated in this study. Each subject performed trunk rotation to maximum range of motion (ROM in a standing position. The kinematics data was collected using a three-dimensional motion analysis system. The outcomes measured were the rotational ROM and the spine/pelvis ratio (SPR in transvers plane at both maximum and 50% rotation position. The coupled angles in sagittal and frontal planes were also measured.No significant differences in rotational ROM of the thorax, pelvis, and spine were observed between two groups at maximum rotation position. However, there was a significant interaction between groups and rotational ROM of pelvis and spine (F = 4.57, p = 0.04, and the SPR in CLBP patients was significantly greater than that of the healthy subjects (CLBP; 0.50 ± 0.10 Control; 0.41 ± 0.12, p = 0.04. The results at 50% rotation position were similar to that at maximum rotation. This indicates a relative increase in spinal rotation in the CLBP patients during trunk rotation. Moreover, the CLBP patients exhibited a significantly higher anterior tilt of the pelvis and extension of the spine in the sagittal plane coupled with rotation.CLBP patients had relative hyper rotational mobility of the spine as well as excessive spinal extension coupled with trunk rotation. These results suggest that uncoordinated trunk rotation might be a functional failure associated with CLBP.

LINKING MOTOR-RELATED BRAIN POTENTIALS AND VELOCITY PROFILES IN MULTI-JOINT ARM REACHING MOVEMENTS

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Julià L Amengual

2014-04-01

Full Text Available The study of the movement related brain potentials (MRPBs needs accurate technical approaches to disentangle the specific patterns of bran activity during the preparation and execution of movements. During the last forty years, synchronizing the electromiographic activation (EMG of the muscle with the electrophysiological recordings (EEG has been commonly ussed for these purposes. However, new clinical approaches in the study of motor diseases and rehabilitation suggest the demand of new paradigms that might go further into the study of the brain activity associated with the kinematics of movement. As a response to this call, we have used a 3-D hand tracking system with the aim to record continuously the position of an ultrasonic sender located on the hand during the performance of multi-joint self-pace movements. We synchronized the time-series of position of velocity of the sender with the EEG recordings, obtaining specific patterns of brain activity as a function of the fluctuations of the kinematics during the natural movement performance. Additionally, the distribution of the brain activity during the preparation and execution phases of movement was similar that reported previously using the EMG, suggesting the validity of our technique. We claim that this paradigm could be usable in patients because of its simplicity and the potential knowledge that can be extracted from clinical protocols.

Quasi-stationary gravitational collapse of slowly rotating bodies in general relativity

Energy Technology Data Exchange (ETDEWEB)

Miller, J C [Oxford Univ. (UK). Dept. of Astrophysics

1977-05-01

This paper presents results of quasi-stationary collapse calculations for a class of slowly rotating non-homogeneous bodies in general relativity. The results are qualitatively similar to those obtained previously for homogeneous models indicating that the effects described for the homogeneous models are likely to have some relevance for the gravitational collapse of real stars towards the black hole state. There is also a discussion of some basic questions associated with such calculations.

An Eye-Movement Study of relational Memory in Adults with Autism Spectrum Disorder.

Science.gov (United States)

Ring, Melanie; Bowler, Dermot M; Gaigg, Sebastian B

2017-10-01

Persons with Autism Spectrum Disorder (ASD) demonstrate good memory for single items but difficulties remembering contextual information related to these items. Recently, we found compromised explicit but intact implicit retrieval of object-location information in ASD (Ring et al. Autism Res 8(5):609-619, 2015). Eye-movement data collected from a sub-sample of the participants are the focus of the current paper. At encoding, trial-by-trial viewing durations predicted subsequent retrieval success only in typically developing (TD) participants. During retrieval, TD compared to ASD participants looked significantly longer at previously studied object-locations compared to alternative locations. These findings extend similar observations recently reported by Cooper et al. (Cognition 159:127-138, 2017a) and demonstrate that eye-movement data can shed important light on the source and nature of relational memory difficulties in ASD.

Age-related changes of dental pulp tissue after experimental tooth movement in rats

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Martina Von Böhl

2016-01-01

Full Text Available It is generally accepted that the effect of orthodontic tooth movement on the dental pulp in adolescents is reversible and that it has no long-lasting effect on pulpal physiology. However, it is not clear yet if the same conclusion is also valid for adult subjects. Thus, in two groups of rats, aged 6 and 40 weeks respectively, 3 molars at one side of the maxilla were moved together in a mesial direction with a standardized orthodontic appliance delivering a force of 10 cN. The contralateral side served as a control. Parasagittal histological sections were prepared after tooth movement for 1, 2, 4, 8, and 12 weeks. The pulp tissue was characterized for the different groups, with special emphasis on cell density, inflammatory cells, vascularity, and odontoblasts. Dimensions of dentin and the pulpal horns was determined and related with the duration of orthodontic force application and age ware evaluated. We found that neither in young nor in adult rats, force application led to long-lasting or irreversible changes in pulpal tissues. Dimensional variables showed significant age-related changes. In conclusion, orthodontic tooth movement per se has no long-lasting or irreversible effect on pulpal tissues, neither in the young nor in the adult animals.

Evolution of magnetized, differentially rotating neutron stars: Simulations in full general relativity

International Nuclear Information System (INIS)

Duez, Matthew D.; Liu, Yuk Tung; Shapiro, Stuart L.; Stephens, Branson C.; Shibata, Masaru

2006-01-01

We study the effects of magnetic fields on the evolution of differentially rotating neutron stars, which can be formed in stellar core collapse or binary neutron star coalescence. Magnetic braking and the magnetorotational instability (MRI) both act on differentially rotating stars to redistribute angular momentum. Simulations of these stars are carried out in axisymmetry using our recently developed codes which integrate the coupled Einstein-Maxwell-MHD equations. We consider stars with two different equations of state (EOS), a gamma-law EOS with Γ=2, and a more realistic hybrid EOS, and we evolve them adiabatically. Our simulations show that the fate of the star depends on its mass and spin. For initial data, we consider three categories of differentially rotating, equilibrium configurations, which we label normal, hypermassive and ultraspinning. Normal configurations have rest masses below the maximum achievable with uniform rotation, and angular momentum below the maximum for uniform rotation at the same rest mass. Hypermassive stars have rest masses exceeding the mass limit for uniform rotation. Ultraspinning stars are not hypermassive, but have angular momentum exceeding the maximum for uniform rotation at the same rest mass. We show that a normal star will evolve to a uniformly rotating equilibrium configuration. An ultraspinning star evolves to an equilibrium state consisting of a nearly uniformly rotating central core, surrounded by a differentially rotating torus with constant angular velocity along magnetic field lines, so that differential rotation ceases to wind the magnetic field. In addition, the final state is stable against the MRI, although it has differential rotation. For a hypermassive neutron star, the MHD-driven angular momentum transport leads to catastrophic collapse of the core. The resulting rotating black hole is surrounded by a hot, massive, magnetized torus undergoing quasistationary accretion, and a magnetic field collimated along

Movement patterns of limb coordination in infant rolling.

Science.gov (United States)

Kobayashi, Yoshio; Watanabe, Hama; Taga, Gentaro

2016-12-01

Infants must perform dynamic whole-body movements to initiate rolling, a key motor skill. However, little is known regarding limb coordination and postural control in infant rolling. To address this lack of knowledge, we examined movement patterns and limb coordination during rolling in younger infants (aged 5-7 months) that had just begun to roll and in older infants (aged 8-10 months) with greater rolling experience. Due to anticipated difficulty in obtaining measurements over the second half of the rolling sequence, we limited our analysis to the first half. Ipsilateral and contralateral limbs were identified on the basis of rolling direction and were classified as either a stationary limb used for postural stability or a moving limb used for controlled movement. We classified the observed movement patterns by identifying the number of stationary limbs and the serial order of combinational limb movement patterns. Notably, older infants performed more movement patterns that involved a lower number of stationary limbs than younger infants. Despite the wide range of possible movement patterns, a small group of basic patterns dominated in both age groups. Our results suggest that the fundamental structure of limb coordination during rolling in the early acquisition stages remains unchanged until at least 8-10 months of age. However, compared to younger infants, older infants exhibited a greater ability to select an effective rotational movement by positioning themselves with fewer stationary limbs and performing faster limb movements.

Effect of Relative Marker Movement on the Calculation of the Foot Torsion Axis Using a Combined Cardan Angle and Helical Axis Approach

Science.gov (United States)

Graf, Eveline S.; Wright, Ian C.; Stefanyshyn, Darren J.

2012-01-01

The two main movements occurring between the forefoot and rearfoot segment of a human foot are flexion at the metatarsophalangeal joints and torsion in the midfoot. The location of the torsion axis within the foot is currently unknown. The purpose of this study was to develop a method based on Cardan angles and the finite helical axis approach to calculate the torsion axis without the effect of flexion. As the finite helical axis method is susceptible to error due to noise with small helical rotations, a minimal amount of rotation was defined in order to accurately determine the torsion axis location. Using simulation, the location of the axis based on data containing noise was compared to the axis location of data without noise with a one-sample t-test and Fisher's combined probability score. When using only data with helical rotation of seven degrees or more, the location of the torsion axis based on the data with noise was within 0.2 mm of the reference location. Therefore, the proposed method allowed an accurate calculation of the foot torsion axis location. PMID:22666303

Effect of Relative Marker Movement on the Calculation of the Foot Torsion Axis Using a Combined Cardan Angle and Helical Axis Approach

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Eveline S. Graf

2012-01-01

Full Text Available The two main movements occurring between the forefoot and rearfoot segment of a human foot are flexion at the metatarsophalangeal joints and torsion in the midfoot. The location of the torsion axis within the foot is currently unknown. The purpose of this study was to develop a method based on Cardan angles and the finite helical axis approach to calculate the torsion axis without the effect of flexion. As the finite helical axis method is susceptible to error due to noise with small helical rotations, a minimal amount of rotation was defined in order to accurately determine the torsion axis location. Using simulation, the location of the axis based on data containing noise was compared to the axis location of data without noise with a one-sample t-test and Fisher's combined probability score. When using only data with helical rotation of seven degrees or more, the location of the torsion axis based on the data with noise was within 0.2 mm of the reference location. Therefore, the proposed method allowed an accurate calculation of the foot torsion axis location.

Generalisation, decision making, and embodiment effects in mental rotation: A neurorobotic architecture tested with a humanoid robot.

Science.gov (United States)

Seepanomwan, Kristsana; Caligiore, Daniele; Cangelosi, Angelo; Baldassarre, Gianluca

2015-12-01

Mental rotation, a classic experimental paradigm of cognitive psychology, tests the capacity of humans to mentally rotate a seen object to decide if it matches a target object. In recent years, mental rotation has been investigated with brain imaging techniques to identify the brain areas involved. Mental rotation has also been investigated through the development of neural-network models, used to identify the specific mechanisms that underlie its process, and with neurorobotics models to investigate its embodied nature. Current models, however, have limited capacities to relate to neuro-scientific evidence, to generalise mental rotation to new objects, to suitably represent decision making mechanisms, and to allow the study of the effects of overt gestures on mental rotation. The work presented in this study overcomes these limitations by proposing a novel neurorobotic model that has a macro-architecture constrained by knowledge held on brain, encompasses a rather general mental rotation mechanism, and incorporates a biologically plausible decision making mechanism. The model was tested using the humanoid robot iCub in tasks requiring the robot to mentally rotate 2D geometrical images appearing on a computer screen. The results show that the robot gained an enhanced capacity to generalise mental rotation to new objects and to express the possible effects of overt movements of the wrist on mental rotation. The model also represents a further step in the identification of the embodied neural mechanisms that may underlie mental rotation in humans and might also give hints to enhance robots' planning capabilities. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Transducers for providing an electrical signal representative of physical movement

International Nuclear Information System (INIS)

Duncombe, E.; Roach, P.F.

1985-01-01

A transducer for use in hostile environments has an externally threaded rod slidable in an internally threaded tube. The threads of rod and tube are of two-start form and define slots in which inductively coupled mineral insulated conductors are located, the conductors being of hairpin form secured at the ends of the rod and tube at the hairpin bend with the hairpin tails in the slots. End diaphragms make a sealed transducer in which the rod can move axially relative to the tube by one half of one pitch of the threads without straining the diaphragms. In a modification rod and tube are arranged to rotate relative to each other up to +-180 0 which effectively also causes a one half pitch movement of the conductors. (author)

Animal perception of seasonal thresholds: changes in elephant movement in relation to rainfall patterns.

Science.gov (United States)

Birkett, Patricia J; Vanak, Abi T; Muggeo, Vito M R; Ferreira, Salamon M; Slotow, Rob

2012-01-01

The identification of temporal thresholds or shifts in animal movement informs ecologists of changes in an animal's behaviour, which contributes to an understanding of species' responses in different environments. In African savannas, rainfall, temperature and primary productivity influence the movements of large herbivores and drive changes at different scales. Here, we developed a novel approach to define seasonal shifts in movement behaviour by examining the movements of a highly mobile herbivore (elephant; Loxodonta africana), in relation to local and regional rainfall patterns. We used speed to determine movement changes of between 8 and 14 GPS-collared elephant cows, grouped into five spatial clusters, in Kruger National Park, South Africa. To detect broad-scale patterns of movement, we ran a three-year daily time-series model for each individual (2007-2009). Piecewise regression models provided the best fit for elephant movement, which exhibited a segmented, waveform pattern over time. Major breakpoints in speed occurred at the end of the dry and wet seasons of each year. During the dry season, female elephant are constrained by limited forage and thus the distances they cover are shorter and less variable. Despite the inter-annual variability of rainfall, speed breakpoints were strongly correlated with both local and regional rainfall breakpoints across all three years. Thus, at a multi-year scale, rainfall patterns significantly affect the movements of elephant. The variability of both speed and rainfall breakpoints across different years highlights the need for an objective definition of seasonal boundaries. By using objective criteria to determine behavioural shifts, we identified a biologically meaningful indicator of major changes in animal behaviour in different years. We recommend the use of such criteria, from an animal's perspective, for delineating seasons or other extrinsic shifts in ecological studies, rather than arbitrarily fixed definitions

Animal perception of seasonal thresholds: changes in elephant movement in relation to rainfall patterns.

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Patricia J Birkett

Full Text Available BACKGROUND: The identification of temporal thresholds or shifts in animal movement informs ecologists of changes in an animal's behaviour, which contributes to an understanding of species' responses in different environments. In African savannas, rainfall, temperature and primary productivity influence the movements of large herbivores and drive changes at different scales. Here, we developed a novel approach to define seasonal shifts in movement behaviour by examining the movements of a highly mobile herbivore (elephant; Loxodonta africana, in relation to local and regional rainfall patterns. METHODOLOGY/PRINCIPAL FINDINGS: We used speed to determine movement changes of between 8 and 14 GPS-collared elephant cows, grouped into five spatial clusters, in Kruger National Park, South Africa. To detect broad-scale patterns of movement, we ran a three-year daily time-series model for each individual (2007-2009. Piecewise regression models provided the best fit for elephant movement, which exhibited a segmented, waveform pattern over time. Major breakpoints in speed occurred at the end of the dry and wet seasons of each year. During the dry season, female elephant are constrained by limited forage and thus the distances they cover are shorter and less variable. Despite the inter-annual variability of rainfall, speed breakpoints were strongly correlated with both local and regional rainfall breakpoints across all three years. Thus, at a multi-year scale, rainfall patterns significantly affect the movements of elephant. The variability of both speed and rainfall breakpoints across different years highlights the need for an objective definition of seasonal boundaries. CONCLUSIONS/SIGNIFICANCE: By using objective criteria to determine behavioural shifts, we identified a biologically meaningful indicator of major changes in animal behaviour in different years. We recommend the use of such criteria, from an animal's perspective, for delineating seasons or

A comparative study of the identification of rotator cuff calcifications ...

African Journals Online (AJOL)

A deposit of calcium in the rotator cuff tendons, also known as calcifying tendinopathy, is a common condition. Calcifications are often associated with significant pain and restriction of shoulder movement. The hypothesis of this retrospective, descriptive study is that ultrasound is more sensitive to detect calcifications in the ...

Relation of chromospheric activity to convection, rotation, and pre-main-sequence evolution

International Nuclear Information System (INIS)

Gilliland, R.L.

1986-01-01

Pre-main-sequence, or T Tauri, stars are characterized by much larger fluxes of nonradiative origin than their main-sequence counterparts. As a class, the T Tauri stars have only moderate rotation rates, making an explanation of their chromospheric properties based on rapid rotation problematic. The recent success of correlating nonradiative fluxes to the Rossby number, Ro = P/sub rot//tau/sub conv/, a central parameter of simple dynamo theories of magnetic field generation, has led to the suggestion that the same relation might be of use in explaining the pre-main-sequence (PMS) stars if tau/sub conv/ is very large. We show that tau/sub conv/ does depend strongly on evolutionary effects above the main sequence (MS), but that this dependence alone cannot account for the high observed nonradiative fluxes. The acoustic flux is also strongly dependent on PMS evolutionary state, and when coupled to the parameterization of magnetic activity based on Ro, these two mechanisms seem capable of explaining the high observed level of chromospheric activity in T Tauri stars. The moment of inertia decreases by two to three order of magnitude during PMS evolution. Since young MS stars do not rotate two to three orders of magnitude faster than PMS stars, rapid loss or redistribution of angular momentum must occur

Analysis of failed rotator cuff repair – Retrospective survey of revisions after open rotator cuff repair

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Rupert Schupfner

2017-07-01

Full Text Available Background Rotator cuff defects are frequently occurring shoulder pathologies associated with pain and movement impairment. Aims The aim of the study was to analyse the pathologies that lead to operative revisions after primary open rotator cuff repair. Methods In 216 patients who underwent primary rotator cuff repair and later required operative revision between 1996 to 2005, pathologies found intraoperatively during the primary operation and during revision surgery were collected, analysed and compared. Results The average age at the time of revision surgery was 54.3 years. The right shoulder (61.6 per cent was more often affected than the left, males (63.4 per cent more often than females. At primary operation – apart from rotator cuff repair – there were the following surgical procedures performed: 190 acromioplasty, 86 Acromiclavicular joint resections, 68 tenodesis, 40 adhesiolysis and 1 tenotomy. If an ACJ-resection had been performed in the primary operation, ACJ-problems were rare in revision surgery (p<0.01. Primary gleno-humeral adhesions were associated with a significant rise in re-tearing rate (p=0.049. Primary absence of adhesions went along with a significant lower rate of adhesions found at revision (p=0.018. Primary performed acromioplasty had no influence on re-tearing rate (p=0.408 or on the rate of subacromial impingement at revision surgery (p=0.709. Conclusion To avoid operative revision after rotator cuff repair relevant copathologies of the shoulder have to be identified before or during operation and treated accordingly. Therefore, even during open rotator cuff repair, the surgeon should initially start with arthroscopy of the shoulder joint and subacromial space to recognise co-pathologies.

InternatIonalIzatIon or natIonalIzatIon by CommunICatIon? the InternatIonal CommunICatIon relatIons of the German suffraGe movement

OpenAIRE

Kinnebrock, Susanne

2011-01-01

The women’s movements of the late nineteenth and early twentieth century were closely connected by a network of manifold communication relations. To analyze the development of social movements and their transnational communication in a systematic way this article presents an analytical framework and then applies it to the German suffrage movement. Considering different stages of domestic social movements (initial phase, organizational phase, phase of establishment) and different types of medi...

The rotating universe

International Nuclear Information System (INIS)

Ruben, G.; Treder, H.J.

1987-01-01

For a long time the question whether the universe rotates or not is discussed. Aspects of Huygens, Newton, Mach and other important historical scientists in this field are reported. The investigations of the mathematician Kurt Groedel in order to prove the rotation of the universe are illustrated. Kurt Groedel has shown that Einstein's gravitational equations of general relativity theory and the cosmological postulate of global homogeneity of cosmic matter (that is the Copernical principle) are not contradictionary to a rotating universe. Abberation measurements, position determination by means of radiointerferometry and methods for the determination of the rotation of the universe from the isotropy of the background radiation are presented. From these experiments it can be concluded that the universe seems not to rotate as already Einstein expected

Evaluation of apical force distribution for orthodontic tooth movements -A flnite element analysis

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S Rex

2010-01-01

Full Text Available FEM is defined as a technique of discrediting a continuum into simple geometric shapes elements, enforcing material properties and governing relationships on these elements giving due consideration to loading and boundary conditions which results in a set of equation, solution which gives the approximate behaviour of the continuum.This study was undertaken to determine the types of orthodontic forces that cause high stress at the root apex. A 3-dimensional finite clement model of a maxillary central incisor, its periodontal ligament (POL,and alveolar bone was constructed on the basis of average anatomic morphology.The maxillary centralincisor was chosen for study because it is one of the teeth at greatest risk for apical root resorption. The material properties of enamel dentin, POL, and bone and 5 different load systems (tipping, intrusion,extrusion,bodily movement,and rotational force were tested. The finite element analysis showed that purely intrusive, extrusive, and rotational forces had stresses concentrated at the apex of the root. The principal stress from a tipping force was located at the alveolar crest. For bodily movement,stress was distributed throughout the PDL;however,it was concentrated more at the alveolar crest. We conclude that intrusive,extrusive, and rotational forces produce more stress at the apex. Bodily movement and tipping forces concentrate forces at the alveolar crest, not at the apex.

Mixed movements/performance-based drawing

DEFF Research Database (Denmark)

Brabrand, Helle

2011-01-01

Mixed Movements is a research project engaged in performance-based architectural drawing. As one in a series working with architectonic implementation in relation to body and movements, the actual project relates body-movement and dynamic drawing and presents the material as interactive ‘space-time-tables’....

Variables affecting orthodontic tooth movement with clear aligners.

Science.gov (United States)

Chisari, Justin R; McGorray, Susan P; Nair, Madhu; Wheeler, Timothy T

2014-04-01

In this study, we examined the impacts of age, sex, root length, bone levels, and bone quality on orthodontic tooth movement. Clear aligners were programmed to move 1 central incisor 1 mm over the course of 8 weeks. Thirty subjects, ages 19 to 64, were enrolled, and measurements were made on digital models (percentage of tooth movement goal achieved). Morphometric features and bone quality were assessed with cone-beam computed tomography. Data from this study were combined with data from 2 similar studies to increase the power for some analyses. The mean percentage of tooth movement goal achieved was 57% overall. Linear regression modeling indicated a cubic relationship between age and tooth movement, with a decreasing rate of movement from ages 18 to 35 years, a slightly increasing rate from ages 35 to 50, and a decreasing rate from ages 50 to 70. The final decreasing trend was not apparent for women. As would be expected, the correlation was significant between the percentage of the goal achieved and the cone-beam computed tomography superimposed linear measures of tooth movement. A significant negative correlation was found between tooth movement and the measurement apex to the center of rotation, but bone quality, as measured by fractal dimension, was not correlated with movement. The relationship between age and tooth movement is complex and might differ for male and female patients. Limited correlations with cone-beam computed tomography morphology and rate of tooth movement were detected. Copyright © 2014 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

P1-20: The Relation of Eye and Hand Movement during Multimodal Recall Memory

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Eun-Sol Kim

2012-10-01

Full Text Available Eye and hand movement tracking has been proven to be a successful tool and is widely used to figure out characteristics of human cognition in language or visual processing (Just & Carpenter, 1976 Cognitive Psychology 8441–480. Eye movement has proven to be a successful measure to figure out characteristics of human language and visual processing (Rayner, 1998 Psychological Bulletin 124(3 372–422. Recently, mouse tracking was used for social-cognition-like categorization of sex-atypical faces and studying spoken-language processes (Magnuson, 2005 PNAS 102(28 9995–9996; Spivey et al., 2005 PNAS 102 10393–10398. Here, we present a framework that uses both eye gaze and hand movement simultaneously for analyzing the relation of them during memory retrieval. We tracked eye and mouse movements when the subject was watching a drama and playing a multimodal memory game (MMG, a cognitive task designed to investigate the recall memory mechanisms in watching video dramas (Zhang, 2009 AAAI 2009 Spring Symposium: Agents that Learn from Human Teachers 144–149. Experimental results show that eye tracking and mouse tracking provide complementary information about underlying cognitive processes. Also, we found some interesting patterns in eye-hand movement during multimodal memory recall.

Capture of fixation by rotational flow; a deterministic hypothesis regarding scaling and stochasticity in fixational eye movements

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Nicholas Mansel Wilkinson

2014-02-01

Full Text Available Visual scan paths exhibit complex, stochastic dynamics. Even during visual fixation, the eye is in constant motion. Fixational drift and tremor are thought to reflect fluctuations in the persistent neural activity of neural integrators in the oculomotor brainstem, which integrate sequences of transient saccadic velocity signals into a short term memory of eye position. Despite intensive research and much progress, the precise mechanisms by which oculomotor posture is maintained remain elusive. Drift exhibits a stochastic statistical profile which has been modelled using random walk formalisms. Tremor is widely dismissed as noise. Here we focus on the dynamical profile of fixational tremor, and argue that tremor may be a signal which usefully reflects the workings of the oculomotor postural control. We identify signatures reminiscent of a certain flavour of transient neurodynamics; toric travelling waves which rotate around a central phase singularity. Spiral waves play an organisational role in dynamical systems at many scales throughout nature, though their potential functional role in brain activity remains a matter of educated speculation. Spiral waves have a repertoire of functionally interesting dynamical properties, including persistence, which suggest that they could in theory contribute to persistent neural activity in the oculomotor postural control system. Whilst speculative, the singularity hypothesis of oculomotor postural control implies testable predictions, and could provide the beginnings of an integrated dynamical framework for eye movements across scales.

Dynamic functional coupling of high resolution EEG potentials related to unilateral internally triggered one-digit movements.

Science.gov (United States)

Urbano, A; Babiloni, C; Onorati, P; Babiloni, F

1998-06-01

Between-electrode cross-covariances of delta (0-3 Hz)- and theta (4-7 Hz)-filtered high resolution EEG potentials related to preparation, initiation. and execution of human unilateral internally triggered one-digit movements were computed to investigate statistical dynamic coupling between these potentials. Significant (P planning, starting, and performance of unilateral movement. The involvement of these cortical areas is supported by the observation that averaged spatially enhanced delta- and theta-bandpassed potentials were computed from the scalp regions where task-related electrical activation of primary sensorimotor areas and supplementary motor area was roughly represented.

Head movements encode emotions during speech and song.

Science.gov (United States)

Livingstone, Steven R; Palmer, Caroline

2016-04-01

When speaking or singing, vocalists often move their heads in an expressive fashion, yet the influence of emotion on vocalists' head motion is unknown. Using a comparative speech/song task, we examined whether vocalists' intended emotions influence head movements and whether those movements influence the perceived emotion. In Experiment 1, vocalists were recorded with motion capture while speaking and singing each statement with different emotional intentions (very happy, happy, neutral, sad, very sad). Functional data analyses showed that head movements differed in translational and rotational displacement across emotional intentions, yet were similar across speech and song, transcending differences in F0 (varied freely in speech, fixed in song) and lexical variability. Head motion specific to emotional state occurred before and after vocalizations, as well as during sound production, confirming that some aspects of movement were not simply a by-product of sound production. In Experiment 2, observers accurately identified vocalists' intended emotion on the basis of silent, face-occluded videos of head movements during speech and song. These results provide the first evidence that head movements encode a vocalist's emotional intent and that observers decode emotional information from these movements. We discuss implications for models of head motion during vocalizations and applied outcomes in social robotics and automated emotion recognition. (c) 2016 APA, all rights reserved).

Rotational and translational Brownian motion

International Nuclear Information System (INIS)

Coffey, W.T.; Salford Univ.

1980-01-01

In this review it is proposed to summarise the work on the theory of the translational and rotational Brownian movement which has been carried on over roughly the past 30 years. The review is intended to take the form of a tutorial paper rather than a list of the results obtained by the various investigators over the period in question. In this vein then it seems appropriate to firstly give a brief account of those parts of the theory of probability which are relevant to the problems under discussion. (orig.)

Frontal eye field sends delay activity related to movement, memory, and vision to the superior colliculus.

Science.gov (United States)

Sommer, M A; Wurtz, R H

2001-04-01

Many neurons within prefrontal cortex exhibit a tonic discharge between visual stimulation and motor response. This delay activity may contribute to movement, memory, and vision. We studied delay activity sent from the frontal eye field (FEF) in prefrontal cortex to the superior colliculus (SC). We evaluated whether this efferent delay activity was related to movement, memory, or vision, to establish its possible functions. Using antidromic stimulation, we identified 66 FEF neurons projecting to the SC and we recorded from them while monkeys performed a Go/Nogo task. Early in every trial, a monkey was instructed as to whether it would have to make a saccade (Go) or not (Nogo) to a target location, which permitted identification of delay activity related to movement. In half of the trials (memory trials), the target disappeared, which permitted identification of delay activity related to memory. In the remaining trials (visual trials), the target remained visible, which permitted identification of delay activity related to vision. We found that 77% (51/66) of the FEF output neurons had delay activity. In 53% (27/51) of these neurons, delay activity was modulated by Go/Nogo instructions. The modulation preceded saccades made into only part of the visual field, indicating that the modulation was movement-related. In some neurons, delay activity was modulated by Go/Nogo instructions in both memory and visual trials and seemed to represent where to move in general. In other neurons, delay activity was modulated by Go/Nogo instructions only in memory trials, which suggested that it was a correlate of working memory, or only in visual trials, which suggested that it was a correlate of visual attention. In 47% (24/51) of FEF output neurons, delay activity was unaffected by Go/Nogo instructions, which indicated that the activity was related to the visual stimulus. In some of these neurons, delay activity occurred in both memory and visual trials and seemed to represent a

EEG patterns in theta and gamma frequency range and their probable relation to human voluntary movement organization.

Science.gov (United States)

Popivanov, D; Mineva, A; Krekule, I

1999-05-21

In experiments with EEG accompanying continuous slow goal-directed voluntary movements we found abrupt short-term transients (STs) of the coefficients of EEG time-varying autoregressive (TVAR) model. The onset of STs indicated (i) a positive EEG wave related to an increase of 3-7 Hz oscillations in time period before the movement start, (ii) synchronization of 35-40 Hz prior to movement start and during the movement when the target is nearly reached. Both these phenomena are expressed predominantly over supplementary motor area, premotor and parietal cortices. These patterns were detected after averaging of EEG segments synchronized to the abrupt changes of the TVAR coefficients computed in the time course of EEG single records. The results are discussed regarding the cognitive aspect of organization of goal-directed movements.

Higher plantar pressure on the medial side in four soccer‐related movements

Science.gov (United States)

Wong, Pui‐lam; Chamari, Karim; De Wei Mao; Wisløff, Ulrik; Hong, Youlian

2007-01-01

Objective To measure the plantar pressure in four soccer‐related movements in 15 male soccer players (mean (SD) age 20.9 (1.3) years, height 173 (4) cm, weight 61.7 (3.6) kg). Design To record plantar pressure distribution, the players wore soccer boots with 12 circular studs and with an insole pressure recorder device equipped with 99 sensors. Plantar pressure was recorded in five successful trials in each of the four soccer‐related movements: running, sideward cutting, 45° cutting and landing from a vertical jump. Each footprint was divided into 10 recorded areas for analysis. Results Compared with running at 3.3 m/s, maximal speed sideward cutting and 45° cutting induced higher peak pressure (pplantar surface as compared with the lateral side. Conclusions These data suggest that the medial side of the plantar surface may be more prone to injuries, and that foot orthosis adoption, improved soccer boot design and specific muscle training could be considered to reduce pressure and the subsequent risk of injury. PMID:17178776

Expectancies Mediate the Relations Among Pain Catastrophizing, Fear of Movement, and Return to Work Outcomes After Whiplash Injury.

Science.gov (United States)

Carriere, Junie S; Thibault, Pascal; Milioto, Maria; Sullivan, Michael J L

2015-12-01

Pain catastrophizing and fear of movement have been identified as key predictors of prolonged work disability after whiplash injury. However, little is known about the processes by which pain catastrophizing and fear of movement affect return to work. This study investigated the mediating role of expectancies on the relations between pain catastrophizing and return to work, and between fear of movement and return to work after whiplash injury. The study sample consisted of 154 individuals with whiplash injury who were enrolled in a multidisciplinary pain rehabilitation program. Participants completed measures of pain catastrophizing, fear of movement, and return-to-work expectancies after admission to a rehabilitation program. A follow-up telephone interview was used to assess work status 1 year after discharge. Consistent with previous research, analyses revealed that expectancies, pain catastrophizing, and fear of movement were significant predictors of return to work at 1-year follow-up. Regression analyses (bootstrapping) revealed that expectancies partially mediated the relation between catastrophizing and return to work. Expectancies completely mediated the relation between fear of movement and return to work. The significant predictive and mediating role of expectancies on return to work argues for the inclusion of expectancies as a specific target of intervention for individuals with whiplash injury. The findings suggest that expectancies might be part of the pathways by which pain catastrophizing and fear of movement affect return-to-work outcomes after whiplash injury. The findings argue for greater attention to return-to-work expectancies as a risk factor for problematic recovery outcomes as well as a target of intervention. Copyright © 2015 American Pain Society. Published by Elsevier Inc. All rights reserved.

Experimental evaluation of the drag force and drag torque acting on a rotating spherical particle moving in fluid

Czech Academy of Sciences Publication Activity Database

Lukerchenko, Nikolay; Kvurt, Y.; Kharlamov, Alexander; Chára, Zdeněk; Vlasák, Pavel

2008-01-01

Roč. 56, č. 2 (2008), s. 88-94 ISSN 0042-790X R&D Projects: GA AV ČR IAA200600603 Institutional research plan: CEZ:AV0Z20600510 Keywords : drag force * drag torque * spherical particle * rotational movement * translational movement Subject RIV: DA - Hydrology ; Limnology

Interpreting Measures of Fundamental Movement Skills and Their Relationship with Health-Related Physical Activity and Self-Concept

Science.gov (United States)

Jarvis, Stuart; Williams, Morgan; Rainer, Paul; Jones, Eleri Sian; Saunders, John; Mullen, Richard

2018-01-01

The aims of this study were to determine proficiency levels of fundamental movement skills using cluster analysis in a cohort of U.K. primary school children; and to further examine the relationships between fundamental movement skills proficiency and other key aspects of health-related physical activity behavior. Participants were 553 primary…

Visual and Haptic Mental Rotation

Directory of Open Access Journals (Sweden)

Satoshi Shioiri

2011-10-01

Full Text Available It is well known that visual information can be retained in several types of memory systems. Haptic information can also be retained in a memory because we can repeat a hand movement. There may be a common memory system for vision and action. On the one hand, it may be convenient to have a common system for acting with visual information. On the other hand, different modalities may have their own memory and use retained information without transforming specific to the modality. We compared memory properties of visual and haptic information. There is a phenomenon known as mental rotation, which is possibly unique to visual representation. The mental rotation is a phenomenon where reaction time increases with the angle of visual target (eg,, a letter to identify. The phenomenon is explained by the difference in time to rotate the representation of the target in the visual sytem. In this study, we compared the effect of stimulus angle on visual and haptic shape identification (two-line shapes were used. We found that a typical effect of mental rotation for the visual stimulus. However, no such effect was found for the haptic stimulus. This difference cannot be explained by the modality differences in response because similar difference was found even when haptical response was used for visual representation and visual response was used for haptic representation. These results indicate that there are independent systems for visual and haptic representations.

Femoral component rotation in patellofemoral joint replacement.

Science.gov (United States)

van Jonbergen, Hans-Peter W; Westerbeek, Robin E

2018-06-01

Clinical outcomes in patellofemoral joint replacement may be related to femoral component rotation. Assessment of rotational alignment is however difficult as patients with isolated patellofemoral osteoarthritis often have trochlear dysplasia. The use of the medial malleolus as a landmark to guide rotation has been suggested. The purpose of our study was to evaluate this technique with regard to femoral component rotation, and to correlate rotation with clinical outcomes at one-year follow-up. Forty-one knees in 39 patients had patellofemoral joint replacement using the Zimmer Gender-Solutions patellofemoral prosthesis. Intraoperatively, we determined femoral component rotational alignment using an extramedullary rod aimed at the inferior tip of the medial malleolus. Postoperatively, we measured the angle between the femoral component and the anatomical transepicondylar axis using CT. The amount of rotation was correlated with clinical outcomes at one-year follow-up. Forty knees in 38 patients were available for one-year follow-up. Mean femoral component rotation relative to the anatomical transepicondylar axis was 1.4° external rotation (range, -3.8 to 5.7°). We found no statistically significant correlation between femoral component rotation and change from baseline KOOS subscales at one-year follow-up. Our findings show that when using the medial malleolus as a landmark to guide rotation, the femoral component of the patellofemoral prosthesis was oriented in external rotation relative to the anatomical transepicondylar axis in 80% of knees. Our study did not show a relation between the amount of external rotation and clinical outcomes. Level III. Copyright © 2018 Elsevier B.V. All rights reserved.

Some geometrical problems related to the rotation camera. Pt. 1

International Nuclear Information System (INIS)

Taupin, D.

1985-01-01

An algorithm for a safe generation of the table of expected reflections in the Arndt-Wonnacott rotation camera is given. It relies upon classic quadratic matrixalgebra. Some mathematical theorems are recalled. This algorithm is part of a series of programs developed at Orsay for the treatment of rotation-camera photographs. (orig.)

Postural reconfiguration and cycle-to-cycle variability in patients with work-related musculoskeletal disorders compared to healthy controls and in relation to pain emerging during a repetitive movement task.

Science.gov (United States)

Longo, Alessia; Meulenbroek, Ruud; Haid, Thomas; Federolf, Peter

2018-05-01

Movement variability in sustained repetitive tasks is an important factor in the context of work-related musculoskeletal disorders. While a popular hypothesis suggests that movement variability can prevent overuse injuries, pain evolving during task execution may also cause variability. The aim of the current study was to investigate, first, differences in movement behavior between volunteers with and without work-related pain and, second, the influence of emerging pain on movement variability. Upper-body 3D kinematics were collected as 22 subjects with musculoskeletal disorders and 19 healthy volunteers performed a bimanual repetitive tapping task with a self-chosen and a given rhythm. Three subgroups were formed within the patient group according to the level of pain the participants experienced during the task. Principal component analysis was applied to 30 joint angle coordinates to characterize in a combined analysis the movement variability associated with reconfigurations of the volunteers' postures and the cycle-to-cycle variability that occurred during the execution of the task. Patients with no task-related pain showed lower cycle-to-cycle variability compared to healthy controls. Findings also indicated an increase in movement variability as pain emerged, manifesting both as frequent postural changes and large cycle-to-cycle variability. The findings suggested a relationship between work-related musculoskeletal disorders and movement variability but further investigation is needed on this issue. Additionally, the findings provided clear evidence that pain increased motor variability. Postural reconfigurations and cycle-to-cycle variability should be considered jointly when investigating movement variability and musculoskeletal disorders. Copyright © 2018 Elsevier Ltd. All rights reserved.

Radial-rotation profile forming: A new processing technology of incremental sheet metal forming

Science.gov (United States)

Laue, Robert; Härtel, Sebastian; Awiszus, Birgit

2018-05-01

Incremental forming processes (i.e., spinning) of sheet metal blanks into cylindrical cups are suitable for lower lot sizes. The produced cups were frequently used as preforms to produce workpieces in further forming steps with additional functions like profiled hollow parts [1]. The incremental forming process radial-rotation profile forming has been developed to enable the production of profiled hollow parts with low sheet thinning and good geometrical accuracy. The two principal forming steps are the production of the preform by rotational swing-folding [2] and the subsequent radial profiling of the hollow part in one clamping position. The rotational swing-folding process is based on a combination of conventional spinning and swing-folding. Therefore, a round blank rotates on a profiled mandrel and due to the swinging of a cylindrical forming tool, the blank is formed to a cup with low sheet thinning. In addition, thickening results at the edge of the blank and wrinkling occurs. However, the wrinkles are formed into the indentation of the profiled mandrel and can be reshaped as an advantage in the second process step, the radial profiling. Due to the rotation and continuous radial feed of a profiled forming tool to the profiled mandrel, the axial profile is formed in the second process step. Because of the minor relative movement in axial direction between tool and blank, low sheet thinning occurs. This is an advantage of the principle of the process.

A rotating dust cloud in general relativity

International Nuclear Information System (INIS)

Bonnor, W.B.

1977-01-01

An axially symmetric, stationary exact solution of Einstein's equations for dust is studied. It is asymptotically flat, and represents a rotating dust cloud extending tenuously to infinity, containing a singularity at the centre. An explanation is given as to why there exists no corresponding solution in Newtonian theory. (author)

Independence of Movement Preparation and Movement Initiation.

Science.gov (United States)

Haith, Adrian M; Pakpoor, Jina; Krakauer, John W

2016-03-09

Initiating a movement in response to a visual stimulus takes significantly longer than might be expected on the basis of neural transmission delays, but it is unclear why. In a visually guided reaching task, we forced human participants to move at lower-than-normal reaction times to test whether normal reaction times are strictly necessary for accurate movement. We found that participants were, in fact, capable of moving accurately ∼80 ms earlier than their reaction times would suggest. Reaction times thus include a seemingly unnecessary delay that accounts for approximately one-third of their duration. Close examination of participants' behavior in conventional reaction-time conditions revealed that they generated occasional, spontaneous errors in trials in which their reaction time was unusually short. The pattern of these errors could be well accounted for by a simple model in which the timing of movement initiation is independent of the timing of movement preparation. This independence provides an explanation for why reaction times are usually so sluggish: delaying the mean time of movement initiation relative to preparation reduces the risk that a movement will be initiated before it has been appropriately prepared. Our results suggest that preparation and initiation of movement are mechanistically independent and may have a distinct neural basis. The results also demonstrate that, even in strongly stimulus-driven tasks, presentation of a stimulus does not directly trigger a movement. Rather, the stimulus appears to trigger an internal decision whether to make a movement, reflecting a volitional rather than reactive mode of control. Copyright © 2016 the authors 0270-6474/16/363007-10$15.00/0.

An investigation of head movement with a view to minimising motion artefact during SPECT and PET imaging of the brain

International Nuclear Information System (INIS)

Patterson, H.; Clarke, G.H.; Guy, R.; McKay, W.J.

1998-01-01

Full text: Motion artefact has long been recognised as a major cause of image degradation. Single Photon Emission Computerised Tomography (SPECT) and Positron Emission Tomography (PET) of the brain are playing an important role in the diagnosis and management of several neurological disorders. If these imaging modalities are to contribute fully to medical imaging it is essential that the improved spatial resolution of these systems is not compromised by patient movement. Thirty volunteer subjects have been examined using a simple video technique and the video images were used to classify and measure head movements which may occur during brain imaging. All subjects demonstrated angular movement within the transverse plane or rotation of the head. Angular movement within the sagittal plane or flexion/extension of the neck occurred in 69% of subjects and 72% of subjects exhibited translational movement of the sagittal plane. There was no movement of the coronal plane; nor was there any translational movement of the sagittal plane. These results suggest that when positioning the patient's head for brain imaging a system of head restraint which minimises rotation of the head should be used if image quality is to be maintained

Effect of rotation on convective mass transfer in rotating channels

International Nuclear Information System (INIS)

Pharoah, J.G.; Djilali, N.

2002-01-01

Laminar flow and mass transfer in rotating channels is investigated in the context of centrifugal membrane separation. The effect of orientation with respect to the rotational axis is examined for rectangular channels of aspect ratio 3 and the Rossby number is varied from 0.3 to 20.9. Both Ro and the channel orientation are found to have a significant effect on the flow. Mass transfer calculations corresponding to reverse osmosis desalination are carried out at various operating pressures and all rotating cases exhibit significant process enhancements at relatively low rotation rates. Finally, while it is common in the membrane literature to correlate mass transfer performance with membrane shear rates this is shown not to be valid in the cases presented herein. (author)

There and back again: putting the vectorial movement planning hypothesis to a critical test.

Science.gov (United States)

Kobak, Eva-Maria; Cardoso de Oliveira, Simone

2014-01-01

Based on psychophysical evidence about how learning of visuomotor transformation generalizes, it has been suggested that movements are planned on the basis of movement direction and magnitude, i.e., the vector connecting movement origin and targets. This notion is also known under the term "vectorial planning hypothesis". Previous psychophysical studies, however, have included separate areas of the workspace for training movements and testing the learning. This study eliminates this confounding factor by investigating the transfer of learning from forward to backward movements in a center-out-and-back task, in which the workspace for both movements is completely identical. Visual feedback allowed for learning only during movements towards the target (forward movements) and not while moving back to the origin (backward movements). When subjects learned the visuomotor rotation in forward movements, initial directional errors in backward movements also decreased to some degree. This learning effect in backward movements occurred predominantly when backward movements featured the same movement directions as the ones trained in forward movements (i.e., when opposite targets were presented). This suggests that learning was transferred in a direction specific way, supporting the notion that movement direction is the most prominent parameter used for motor planning.

Adaptive, Small-Rotation-Based, Corotational Technique for Analysis of 2D Nonlinear Elastic Frames

Directory of Open Access Journals (Sweden)

Jaroon Rungamornrat

2014-01-01

Full Text Available This paper presents an efficient and accurate numerical technique for analysis of two-dimensional frames accounted for both geometric nonlinearity and nonlinear elastic material behavior. An adaptive remeshing scheme is utilized to optimally discretize a structure into a set of elements where the total displacement can be decomposed into the rigid body movement and one possessing small rotations. This, therefore, allows the force-deformation relationship for the latter part to be established based on small-rotation-based kinematics. Nonlinear elastic material model is integrated into such relation via the prescribed nonlinear moment-curvature relationship. The global force-displacement relation for each element can be derived subsequently using corotational formulations. A final system of nonlinear algebraic equations along with its associated gradient matrix for the whole structure is obtained by a standard assembly procedure and then solved numerically by Newton-Raphson algorithm. A selected set of results is then reported to demonstrate and discuss the computational performance including the accuracy and convergence of the proposed technique.

THE OPTIMAL ROTATIONS OF GMELINA STAND ON TWO CARBON PROJECTS: LENGTHENING ROTATION AND AFFORESTATION

Directory of Open Access Journals (Sweden)

Yonky Indrajaya

2016-12-01

Full Text Available Forest plantation may contribute economically and socially as a provider of wood raw materials for industry and providing jobs for local people. In addition, forest plantation may also contribute as watershed protection and carbon sequestration. Projects on carbon sequestration from plantation forest can be conducted in two types: (1 afforestation and (2 lengthening forest rotation. One of the potential carbon markets operationalized in the field is voluntary market with Verified Carbon Standard mechanism. This study aimed to analyze the optimal rotations of gmelina forests on two carbon projects: lengthening rotation and afforestation. The method used in this study was by using Hartman model ( i.e. Faustmann by maximizing profit with the revenue source from timber and carbon sequestration project. The results of this study showed that carbon price will affect the optimal rotation for lengthening forest rotation of VCS project. Meanwhile, for VCS afforestation project, carbon price had no effect on the optimal rotation on gmelina forest. The NPV value of afforestation project was relatively higher than that of NPV value of lengthening forest rotation project, since the amount of carbon that can be credited relatively higher in afforestation project.

Sound localization with head movement: implications for 3-d audio displays.

Directory of Open Access Journals (Sweden)

Ken Ian McAnally

2014-08-01

Full Text Available Previous studies have shown that the accuracy of sound localization is improved if listeners are allowed to move their heads during signal presentation. This study describes the function relating localization accuracy to the extent of head movement in azimuth. Sounds that are difficult to localize were presented in the free field from sources at a wide range of azimuths and elevations. Sounds remained active until the participants’ heads had rotated through windows ranging in width of 2°, 4°, 8°, 16°, 32°, or 64° of azimuth. Error in determining sound-source elevation and the rate of front/back confusion were found to decrease with increases in azimuth window width. Error in determining sound-source lateral angle was not found to vary with azimuth window width. Implications for 3-d audio displays: The utility of a 3-d audio display for imparting spatial information is likely to be improved if operators are able to move their heads during signal presentation. Head movement may compensate in part for a paucity of spectral cues to sound-source location resulting from limitations in either the audio signals presented or the directional filters (i.e., head-related transfer functions used to generate a display. However, head movements of a moderate size (i.e., through around 32° of azimuth may be required to ensure that spatial information is conveyed with high accuracy.

Shear zones between rock units with no relative movement

DEFF Research Database (Denmark)

Koyi, Hemin; Schmeling, Harro; Burchardt, Steffi

2013-01-01

Shear zones are normally viewed as relatively narrow deformation zones that accommodate relative displacement between two "blocks" that have moved past each other in opposite directions. This study reports localized zones of shear between adjacent blocks that have not moved past each other. Such ...... given credit for and may be responsible for some reverse kinematics reported in shear zones....... or wakes, elongated bodies (vertical plates or horizontal rod-like bodies) produce tabular shear zones or wakes. Unlike conventional shear zones across which shear indicators usually display consistent symmetries, shear indicators on either side of the shear zone or wake reported here show reverse...... kinematics. Thus profiles exhibit shear zones with opposed senses of movement across their center-lines or -planes.We have used field observations and results from analytical and numerical models to suggest that examples of wakes are the transit paths that develop where denser blocks sink within salt...

Social movements and science

DEFF Research Database (Denmark)

Jamison, Andrew

2006-01-01

The article examines the role of social movements in the development of scientific knowledge. Interactions between social movements and science in broad, historical terms are discussed. The relations between the new social movements of the 1960s and 1970s and changes in the contemporary scientific...

Tooth movement characteristics in relation to root resorption in young and adult rats.

NARCIS (Netherlands)

Ren, Y.; Maltha, J.C.; Kuijpers-Jagtman, A.M.

2007-01-01

The aim of this study was to investigate tooth movement characteristics in relation to root resorption in young and adult rats. Two groups of 30 rats each (aged 6 wk and 9-12 months, respectively) were used. Standardized orthodontic appliances were placed to move the maxillary molars mesially.

Tooth movement characteristics in relation to root resorption in young and adult rats

NARCIS (Netherlands)

Ren, Yijin; Maltha, Jaap C.; Kuijpers-Jagtman, Anne Marie

2007-01-01

The aim of this study was to investigate tooth movement characteristics in relation to root resorption in young and adult rats. Two groups of 30 rats each (aged 6 wk and 9-12 months, respectively) were used. Standardized orthodontic appliances were placed to move the maxillary molars mesially.

Using diel movement behavior to infer foraging strategies related to ecological and social factors in elephants.

Science.gov (United States)

Polansky, Leo; Douglas-Hamilton, Iain; Wittemyer, George

2013-01-01

Adaptive movement behaviors allow individuals to respond to fluctuations in resource quality and distribution in order to maintain fitness. Classically, studies of the interaction between ecological conditions and movement behavior have focused on such metrics as travel distance, velocity, home range size or patch occupancy time as the salient metrics of behavior. Driven by the emergence of very regular high frequency data, more recently the importance of interpreting the autocorrelation structure of movement as a behavioral metric has become apparent. Studying movement of a free ranging African savannah elephant population, we evaluated how two movement metrics, diel displacement (DD) and movement predictability (MP - the degree of autocorrelated movement activity at diel time scales), changed in response to variation in resource availability as measured by the Normalized Difference Vegetation Index. We were able to capitalize on long term (multi-year) yet high resolution (hourly) global positioning system tracking datasets, the sample size of which allows robust analysis of complex models. We use optimal foraging theory predictions as a framework to interpret our results, in particular contrasting the behaviors across changes in social rank and resource availability to infer which movement behaviors at diel time scales may be optimal in this highly social species. Both DD and MP increased with increasing forage availability, irrespective of rank, reflecting increased energy expenditure and movement predictability during time periods of overall high resource availability. However, significant interactions between forage availability and social rank indicated a stronger response in DD, and a weaker response in MP, with increasing social status. Relative to high ranking individuals, low ranking individuals expended more energy and exhibited less behavioral movement autocorrelation during lower forage availability conditions, likely reflecting sub-optimal movement

Rotator cuff ruptures of the shoulder joint, sonography - arthrography

International Nuclear Information System (INIS)

Triebel, H.J.; Wening, V.; Witte, G.; Hamburg Univ.

1986-01-01

47 patients suspected of rutpure of the rotator cuff were sonographed and arthrographed. Rupture of the rotator cuff was diagnosed in 12 cases, both diagnostic methods yielding the same result. In 29 patients sonography and arthrography did not reveal any abnormal findings. Six ruptures evident in sonography were not confirmed by arthrography and were considered false positive. Direct pointers towards rupture of the cuff would be: echoless defects, cuff cannot be visualised fully or in part and irregularities of movement during dynamic examination. Echoless 'cystic' areas in the periarticular soft parts must be considered an indirect pointer. Echorich focal findings in the echopoor cuff represent a differential diagnostic problem and we cannot give a final assessment as yet. Shoulder sonography is justified as a screening method in suspicion of rotator cuff rupture before initiating arthrography. If sonography reveals no abnormal findings, shoulder arthrography need not be performed. (orig.) [de

Measuring the wobble of radiation field centers during gantry rotation and collimator movement on a linear accelerator

International Nuclear Information System (INIS)

Du, Weiliang; Gao, Song

2011-01-01

Purpose: The isocenter accuracy of a linear accelerator is often assessed with star-shot films. This approach is limited in its ability to quantify three dimensional wobble of radiation field centers (RFCs). The authors report a Winston-Lutz based method to measure the 3D wobble of RFCs during gantry rotation, collimator rotation, and collimator field size change. Methods: A stationary ball-bearing phantom was imaged using multileaf collimator-shaped radiation fields at various gantry angles, collimator angles, and field sizes. The center of the ball-bearing served as a reference point, to which all RFCs were localized using a computer algorithm with subpixel accuracy. Then, the gantry rotation isocenter and the collimator rotation axis were derived from the coordinates of these RFCs. Finally, the deviation or wobble of the individual RFC from the derived isocenter or rotation axis was quantified. Results: The results showed that the RFCs were stable as the field size of the multileaf collimator was varied. The wobble of RFCs depended on the gantry angle and the collimator angle and was reproducible, indicating that the mechanical imperfections of the linac were mostly systematic and quantifiable. It was found that the 3D wobble of RFCs during gantry rotation was reduced after compensating for a constant misalignment of the multileaf collimator. Conclusions: The 3D wobble of RFCs can be measured with submillimeter precision using the proposed method. This method provides a useful tool for checking and adjusting the radiation isocenter tightness of a linac.

Measuring the wobble of radiation field centers during gantry rotation and collimator movement on a linear accelerator

Energy Technology Data Exchange (ETDEWEB)

Du, Weiliang; Gao, Song [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas, 77030 (United States)

2011-08-15

Purpose: The isocenter accuracy of a linear accelerator is often assessed with star-shot films. This approach is limited in its ability to quantify three dimensional wobble of radiation field centers (RFCs). The authors report a Winston-Lutz based method to measure the 3D wobble of RFCs during gantry rotation, collimator rotation, and collimator field size change. Methods: A stationary ball-bearing phantom was imaged using multileaf collimator-shaped radiation fields at various gantry angles, collimator angles, and field sizes. The center of the ball-bearing served as a reference point, to which all RFCs were localized using a computer algorithm with subpixel accuracy. Then, the gantry rotation isocenter and the collimator rotation axis were derived from the coordinates of these RFCs. Finally, the deviation or wobble of the individual RFC from the derived isocenter or rotation axis was quantified. Results: The results showed that the RFCs were stable as the field size of the multileaf collimator was varied. The wobble of RFCs depended on the gantry angle and the collimator angle and was reproducible, indicating that the mechanical imperfections of the linac were mostly systematic and quantifiable. It was found that the 3D wobble of RFCs during gantry rotation was reduced after compensating for a constant misalignment of the multileaf collimator. Conclusions: The 3D wobble of RFCs can be measured with submillimeter precision using the proposed method. This method provides a useful tool for checking and adjusting the radiation isocenter tightness of a linac.

Differences between Perception and Eye Movements during Complex Motions

Science.gov (United States)

Holly, Jan E.; Davis, Saralin M.; Sullivan, Kelly E.

2013-01-01

During passive whole-body motion in the dark, the motion perceived by subjects may or may not be veridical. Either way, reflexive eye movements are typically compensatory for the perceived motion. However, studies are discovering that for certain motions, the perceived motion and eye movements are incompatible. The incompatibility has not been explained by basic differences in gain or time constants of decay. This paper uses three-dimensional modeling to investigate gondola centrifugation (with a tilting carriage) and off-vertical axis rotation. The first goal was to determine whether known differences between perceived motions and eye movements are true differences when all three-dimensional combinations of angular and linear components are considered. The second goal was to identify the likely areas of processing in which perceived motions match or differ from eye movements, whether in angular components, linear components and/or dynamics. The results were that perceived motions are more compatible with eye movements in three dimensions than the one-dimensional components indicate, and that they differ more in their linear than their angular components. In addition, while eye movements are consistent with linear filtering processes, perceived motion has dynamics that cannot be explained by basic differences in time constants, filtering, or standard GIF-resolution processes. PMID:21846952

Social-movement analysis of the American antinuclear movement

International Nuclear Information System (INIS)

Ladd, A.E.

1981-01-01

Utilizing data from a survey of participants at the May 6, 1979 antinuclear rally in Washington, DC (N = 420), this dissertation explored some of the major structural and ideological characteristics of the American Antinuclear Movement. By organizing the data around three of the key analytical concepts in the study of social movements - mobilization, recruitment, and ideology - the author was able to derive from the demonstration sample a descriptive and illustrative analysis of those individuals, organizations, and processes involved in the national antinuclear crusade. Given that few researchers have actively studied the antinuclear movement beyond the scope of local or regional protests, this work constitutes the only empirical study to date examining a cross section of the movement's participants from a sociological perspective. It is also one of the few attempts to use a national demonstration as a social laboratory for the study of a social movement in general. In terms of the mobilization variables examined in the study, it was found that organizational networks, past movement activism, and individual resources were important factors in the May 6 mobilization effort. While less than one-half of the demonstrators were part of the antinuclear organizational network per se, most of them had been active in the major protest movements of the 1960's and 1970's. The demonstrators were relatively high in socio-economic resources and had occupational or educational schedules conducive to creating the necessary discretionary time for movement participation

Human vertical eye movement responses to earth horizontal pitch

Science.gov (United States)

Wall, C. 3rd; Petropoulos, A. E.

1993-01-01

The vertical eye movements in humans produced in response to head-over-heels constant velocity pitch rotation about a horizontal axis resemble those from other species. At 60 degrees/s these are persistent and tend to have non-reversing slow components that are compensatory to the direction of rotation. In most, but not all subjects, the slow component velocity was well characterized by a rapid build-up followed by an exponential decay to a non-zero baseline. Super-imposed was a cyclic or modulation component whose frequency corresponded to the time for one revolution and whose maximum amplitude occurred during a specific head orientation. All response components (exponential decay, baseline and modulation) were larger during pitch backward compared to pitch forward runs. Decay time constants were shorter during the backward runs, thus, unlike left to right yaw axis rotation, pitch responses display significant asymmetries between paired forward and backward runs.

Galaxy luminosity function and Tully-Fisher relation: reconciled through rotation-curve studies

International Nuclear Information System (INIS)

Cattaneo, Andrea; Salucci, Paolo; Papastergis, Emmanouil

2014-01-01

The relation between galaxy luminosity L and halo virial velocity v vir required to fit the galaxy luminosity function differs from the observed Tully-Fisher relation between L and disk speed v rot . Because of this, the problem of reproducing the galaxy luminosity function and the Tully-Fisher relation simultaneously has plagued semianalytic models since their inception. Here we study the relation between v rot and v vir by fitting observational average rotation curves of disk galaxies binned in luminosity. We show that the v rot -v vir relation that we obtain in this way can fully account for this seeming inconsistency. Therefore, the reconciliation of the luminosity function with the Tully-Fisher relation rests on the complex dependence of v rot on v vir , which arises because the ratio of stellar mass to dark matter mass is a strong function of halo mass.

Finite element analysis of the effect of force directions on tooth movement in extraction space closure with miniscrew sliding mechanics.

Science.gov (United States)

Kojima, Yukio; Kawamura, Jun; Fukui, Hisao

2012-10-01

Miniscrews placed in bone have been used as orthodontic anchorage in extraction space closure with sliding mechanics. The movement patterns of the teeth depend on the force directions. To move the teeth in a desired pattern, the appropriate direction of force must be selected. The purpose of this article is to clarify the relationship between force directions and movement patterns. By using the finite element method, orthodontic movements were simulated based on the remodeling law of the alveolar bone. The power arm length and the miniscrew position were varied to change the force directions. When the power arm was lengthened, rotation of the entire maxillary dentition decreased. The posterior teeth were effective for preventing rotation of the anterior teeth through an archwire. In cases of a high position of a miniscrew, bodily tooth movement was almost achieved. The vertical component of the force produced intrusion or extrusion of the entire dentition. Within the limits of the method, the mechanical simulations demonstrated the effect of force direction on movement patterns. Copyright © 2012 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

Rotator cuff muscle degeneration and tear severity related to myogenic, adipogenic, and atrophy genes in human muscle.

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Shah, Shivam A; Kormpakis, Ioannis; Cavinatto, Leonardo; Killian, Megan L; Thomopoulos, Stavros; Galatz, Leesa M

2017-12-01

Large rotator cuff tear size and advanced muscle degeneration can affect reparability of tears and compromise tendon healing. Clinicians often rely on direct measures of rotator cuff tear size and muscle degeneration from magnetic resonance imaging (MRI) to determine whether the rotator cuff tear is repairable. The objective of this study was to identify the relationship between gene expression changes in rotator cuff muscle degeneration to standard data available to clinicians. Radiographic assessment of preoperative rotator cuff tear severity was completed for 25 patients with varying magnitudes of rotator cuff tears. Tear width and retraction were measured using MRI, and Goutallier grade, tangent (tan) sign, and Thomazeau grade were determined. Expression of myogenic-, adipogenic-, atrophy-, and metabolism-related genes in biopsied muscles were correlated with tear width, tear retraction, Goutallier grade, tan sign, and Thomazeau grade. Tear width positively correlated with Goutallier grade in both the supraspinatus (r = 0.73) and infraspinatus (r = 0.77), along with tan sign (r = 0.71) and Thomazeau grade (r = 0.68). Decreased myogenesis (Myf5), increased adipogenesis (CEBPα, Lep, Wnt10b), and decreased metabolism (PPARα) correlated with radiographic assessments. Gene expression changes suggest that rotator cuff tears lead to a dramatic molecular response in an attempt to maintain normal muscle tissue, increase adipogenesis, and decrease metabolism. Fat accumulation and muscle atrophy appear to stem from endogenous changes rather than from changes mediated by infiltrating cells. Results suggest that chronic unloading of muscle, induced by rotator cuff tear, disrupts muscle homeostasis. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2808-2814, 2017. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Cystic Lesions in the Greater Tuberosity of the Humerus: The Relation to Rotator Cuff Tears and Age

International Nuclear Information System (INIS)

Kim, Gang Deuk; Oh, Jung Taek

2008-01-01

This study was designed to investigate the location of cystic lesions in the greater tuberosity of the humerus and the relationship to rotator cuff tears and age. A total of 78 patients (age range, 19-82 years; mean age, 51 years) who underwent arthroscopy or open surgery after MR arthrography (MRA) for a painful shoulder were enrolled in the study. The location of the cystic lesions were classified as 'A' for a supraspinatus insertion site, as 'C' for an infraspinatus insertion site, as 'B' for both a supraspinatus and infraspinatus insertion site, as 'BG' for a site posterior to the bicipital groove and as 'P' for a site at the bare area of the humeral head. The location of cystic lesions and supraspinatus and infraspinatus tears were evaluated on MRA. Statistical analyses used the chi-squared test and logistic regression. 'BG' and 'A' cystic lesions were related to the presence of a supraspinatus tear, 'C' cystic lesions were related to the presence of an infraspinatus tear and 'B' cystic lesions were related to the presence of both supraspinatus and infraspinatus tears (p < 0.05). 'P' cystic lesions were not related to the presence of rotator cuff tears. The incidence of cystic lesions increased with age, but with no statistical correlation. Cystic lesions at the supraspinatus and infraspinatus insertion sites are useful to predict the presence of a rotator cuff tear, but cystic lesions were not age related

Predicting Functional Recovery in Chronic Stroke Rehabilitation Using Event-Related Desynchronization-Synchronization during Robot-Assisted Movement

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Gramigna, Cristina; Franceschetti, Silvana

2016-01-01

Although rehabilitation robotics seems to be a promising therapy in the rehabilitation of the upper limb in stroke patients, consensus is still lacking on its additive effects. Therefore, there is a need for determining the possible success of robotic interventions on selected patients, which in turn determine the necessity for new investigating instruments supporting the treatment decision-making process and customization. The objective of the work presented in this preliminary study was to verify that fully robot assistance would not affect the physiological oscillatory cortical activity related to a functional movement in healthy subjects. Further, the clinical results following the robotic treatment of a chronic stroke patient, who positively reacted to the robotic intervention, were analyzed and discussed. First results show that there is no difference in EEG activation pattern between assisted and no-assisted movement in healthy subjects. Even more importantly, the patient's pretreatment EEG activation pattern in no-assisted movement was completely altered, while it recovered to a quasi-physiological one in robot-assisted movement. The functional improvement following treatment was large. Using pretreatment EEG recording during robot-assisted movement might be a valid approach to assess the potential ability of the patient for recovering. PMID:27057546

Measurement of prostate movement over the course of routine radiotherapy using implanted markers

International Nuclear Information System (INIS)

Balter, James M.; Sandler, Howard M.; Lam, Kwok; Bree, Robert L.; Lichter, Allen S.; Haken, Randall K. ten

1995-01-01

Purpose: To measure the range and frequency of occurrence of intertreatment movement of the prostate gland over the course of radiotherapy, and to demonstrate that the prostate may move independently of the surrounding bones of the pelvis. Methods and Materials: Ten patients underwent implantation of radiopaque markers around the prostate. Orthogonal portal films were taken at multiple stages during the course of treatment and digitized. An image registration tool was used to solve for film detector placement and, subsequently, to determine positional changes between structures on a reference portal image pair and all subsequent pairs for each patient. Transformations describing prostate movement were measured independently of those describing setup variations of the pelvic girdle. Results: Translation and/or rotation of the prostate was detected in 70% of the treatments for which films were taken. The maximum measured displacement was 7.5 mm along a major axis. Typical translations of the prostate were between 0-4 mm. The translation and rotation had a predominant direction, suggesting a natural axis for prostate movement. Conclusion: Although significant prostate displacement can occur between treatments, the typical range of movement seen along a major axis was less than 5 mm. Proper treatment planning should consider the movement of the target independent of surrounding bony anatomy. Advances in online portal imaging, image registration, and dynamic field shaping may permit shaped fields that encompass the prostate gland in its position at the time of treatment, allowing for the use of smaller fields while ensuring proper target coverage

Influence of axial movement on fatigue of PROFILE* NI-TI rotary instruments: an in vitro evaluation

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Avoaka, Marie-Chantal; Haïkel, Youssef

2010-01-01

The aim of this study was to evaluate the influence of the axial movement and the angle of curve (in degrees) on fatigue of nickel-titanium (Ni-Ti) ProFile’ rotary endodontic instruments. Ni-Ti ProFile’ rotary instruments (Maillefer SA, Ballaigues, Switzerland), 25 mm long in the range of ISO size 15 to 40 with two tapers (0.4 and 0.6) were evaluated. They are divided in two groups: the instruments with axial movement and those without axial movement. The system used to test the fatigue is maintained in mechanical conditions as close as possible to the clinical situation. The axial movement is in the order of 2mm in corono-apical direction with a frequency of 1Hz. The concave radii incorporating a notched V-form for guiding the instruments were: 5; 7,5 and 10 mm. The rotary system is mounted on an electric handpiece and rotated at 350 rpm speed as recommended by the manufacturers. The instruments are rotated until their separation, and the time, in seconds, is recorded. Statístícal evaluation is undertaken using a two-way t-test to identify significant differences between variables in the study (p engine drive ProFile’ instruments incorporating an axial movement and the instruments without axial movement with the same radius of curvature, size and taper. The incorporation of the axial movement increases significantly the life-span of the ProFile’ rotary instruments. This should reduce the risk of the instrument separation during the endodontic treatment. PMID:20507289

Separating movement and gravity components in an acceleration signal and implications for the assessment of human daily physical activity.

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van Hees, Vincent T; Gorzelniak, Lukas; Dean León, Emmanuel Carlos; Eder, Martin; Pias, Marcelo; Taherian, Salman; Ekelund, Ulf; Renström, Frida; Franks, Paul W; Horsch, Alexander; Brage, Søren

2013-01-01

Human body acceleration is often used as an indicator of daily physical activity in epidemiological research. Raw acceleration signals contain three basic components: movement, gravity, and noise. Separation of these becomes increasingly difficult during rotational movements. We aimed to evaluate five different methods (metrics) of processing acceleration signals on their ability to remove the gravitational component of acceleration during standardised mechanical movements and the implications for human daily physical activity assessment. An industrial robot rotated accelerometers in the vertical plane. Radius, frequency, and angular range of motion were systematically varied. Three metrics (Euclidian norm minus one [ENMO], Euclidian norm of the high-pass filtered signals [HFEN], and HFEN plus Euclidean norm of low-pass filtered signals minus 1 g [HFEN+]) were derived for each experimental condition and compared against the reference acceleration (forward kinematics) of the robot arm. We then compared metrics derived from human acceleration signals from the wrist and hip in 97 adults (22-65 yr), and wrist in 63 women (20-35 yr) in whom daily activity-related energy expenditure (PAEE) was available. In the robot experiment, HFEN+ had lowest error during (vertical plane) rotations at an oscillating frequency higher than the filter cut-off frequency while for lower frequencies ENMO performed better. In the human experiments, metrics HFEN and ENMO on hip were most discrepant (within- and between-individual explained variance of 0.90 and 0.46, respectively). ENMO, HFEN and HFEN+ explained 34%, 30% and 36% of the variance in daily PAEE, respectively, compared to 26% for a metric which did not attempt to remove the gravitational component (metric EN). In conclusion, none of the metrics as evaluated systematically outperformed all other metrics across a wide range of standardised kinematic conditions. However, choice of metric explains different degrees of variance in

Separating movement and gravity components in an acceleration signal and implications for the assessment of human daily physical activity.

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Vincent T van Hees

Full Text Available INTRODUCTION: Human body acceleration is often used as an indicator of daily physical activity in epidemiological research. Raw acceleration signals contain three basic components: movement, gravity, and noise. Separation of these becomes increasingly difficult during rotational movements. We aimed to evaluate five different methods (metrics of processing acceleration signals on their ability to remove the gravitational component of acceleration during standardised mechanical movements and the implications for human daily physical activity assessment. METHODS: An industrial robot rotated accelerometers in the vertical plane. Radius, frequency, and angular range of motion were systematically varied. Three metrics (Euclidian norm minus one [ENMO], Euclidian norm of the high-pass filtered signals [HFEN], and HFEN plus Euclidean norm of low-pass filtered signals minus 1 g [HFEN+] were derived for each experimental condition and compared against the reference acceleration (forward kinematics of the robot arm. We then compared metrics derived from human acceleration signals from the wrist and hip in 97 adults (22-65 yr, and wrist in 63 women (20-35 yr in whom daily activity-related energy expenditure (PAEE was available. RESULTS: In the robot experiment, HFEN+ had lowest error during (vertical plane rotations at an oscillating frequency higher than the filter cut-off frequency while for lower frequencies ENMO performed better. In the human experiments, metrics HFEN and ENMO on hip were most discrepant (within- and between-individual explained variance of 0.90 and 0.46, respectively. ENMO, HFEN and HFEN+ explained 34%, 30% and 36% of the variance in daily PAEE, respectively, compared to 26% for a metric which did not attempt to remove the gravitational component (metric EN. CONCLUSION: In conclusion, none of the metrics as evaluated systematically outperformed all other metrics across a wide range of standardised kinematic conditions. However, choice

Rotational dynamics with Tracker

International Nuclear Information System (INIS)

Eadkhong, T; Danworaphong, S; Rajsadorn, R; Jannual, P

2012-01-01

We propose the use of Tracker, freeware for video analysis, to analyse the moment of inertia (I) of a cylindrical plate. Three experiments are performed to validate the proposed method. The first experiment is dedicated to find the linear coefficient of rotational friction (b) for our system. By omitting the effect of such friction, we derive I for a cylindrical plate rotated around its central axis from the other two experiments based on the relation between torque and angular acceleration of rotational motion and conservation of energy. Movies of the rotating plate and hung masses are recorded. As a result, we have the deviation of I from its theoretical value of 0.4% and 3.3%, respectively. Our setup is completely constructed from locally available inexpensive materials and the experimental results indicate that the system is highly reliable. This work should pave the way for those who prefer to build a similar setup from scratch at relatively low cost compared to commercial units. (paper)

Open-Ended Measurement of Whole-Body Movement: A Feasibility Study

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Finn, Michael T. M.

2018-02-01

Full Text Available As the importance of embodiment emerges for psychology, there is a need to advance methodology for measuring the dynamics of movement in an open-ended fashion. Such a tool should be versatile across contexts and track spontaneous and natural movement with minimal constraints. We test the feasibility of a method for measuring whole-body movement over time that attempts to meet this need. We use a motion capture system comprised of two Microsoft Kinect version 2.0 cameras and iPiSoft Motion Capture software, and compare its estimates of magnitude rotational velocity and whole-body movement complexity (multivariate multiscale sample entropy; MMSE to that of a gold standard motion capture system across a variety of movement sequences. The candidate system satisfactorily estimated the instantaneous velocity of 13 body segments in agreement with the gold standard system across movement sequences demonstrating initial feasibility of this process. Summary calculations of velocity by sequence and MMSE calculations were also in high agreement with the gold standard, crucially suggesting that the candidate system could pick up on the complex dynamics of movement over time. The candidate system was feasible and demonstrates preliminary validity for general use in the tracking of continuous human movement for clinical and experimental psychology. We also provide R code and sample data for the importing and processing of movement data exported from iPiSoft Motion Capture Studio.

The interference effects of non-rotated versus counter-rotated trials in visuomotor adaptation.

Science.gov (United States)

Hinder, Mark R; Walk, Laura; Woolley, Daniel G; Riek, Stephan; Carson, Richard G

2007-07-01

An isometric torque-production task was used to investigate interference and retention in adaptation to multiple visuomotor environments. Subjects produced isometric flexion-extension and pronation-supination elbow torques to move a cursor to acquire targets as quickly as possible. Adaptation to a 30 degrees counter-clockwise (CCW) rotation (task A), was followed by a period of rest (control), trials with no rotation (task B0), or trials with a 60 degrees clockwise (CW) rotation (task B60). For all groups, retention of task A was assessed 5 h later. With initial training, all groups reduced the angular deviation of cursor paths early in the movements, indicating feedforward adaptation. For the control group, performance at commencement of the retest was significantly better than that at the beginning of the initial learning. For the B0 group, performance in the retest of task A was not dissimilar to that at the start of the initial learning, while for the B60 group retest performance in task A was markedly worse than initially observed. Our results indicate that close juxtaposition of two visuomotor environments precludes improved retest performance in the initial environment. Data for the B60 group, specifically larger angular errors upon retest compared with initial exposures, are consistent with the presence of anterograde interference. Furthermore, full interference occurred even when the visuomotor environment encountered in the second task was not rotated (B0). This latter novel result differs from those obtained for force field learning, where interference does not occur when task B does not impose perturbing forces, i.e., when B consists of a null field (Brashers-Krug et al., Nature 382:252-255, 1996). The results are consistent with recent proposals suggesting different interference mechanisms for visuomotor (kinematic) compared to force field (dynamic) adaptations, and have implications for the use of washout trials when studying interference between

Prediction of movement intention using connectivity within motor-related network: An electrocorticography study.

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Kang, Byeong Keun; Kim, June Sic; Ryun, Seokyun; Chung, Chun Kee

2018-01-01

Most brain-machine interface (BMI) studies have focused only on the active state of which a BMI user performs specific movement tasks. Therefore, models developed for predicting movements were optimized only for the active state. The models may not be suitable in the idle state during resting. This potential maladaptation could lead to a sudden accident or unintended movement resulting from prediction error. Prediction of movement intention is important to develop a more efficient and reasonable BMI system which could be selectively operated depending on the user's intention. Physical movement is performed through the serial change of brain states: idle, planning, execution, and recovery. The motor networks in the primary motor cortex and the dorsolateral prefrontal cortex are involved in these movement states. Neuronal communication differs between the states. Therefore, connectivity may change depending on the states. In this study, we investigated the temporal dynamics of connectivity in dorsolateral prefrontal cortex and primary motor cortex to predict movement intention. Movement intention was successfully predicted by connectivity dynamics which may reflect changes in movement states. Furthermore, dorsolateral prefrontal cortex is crucial in predicting movement intention to which primary motor cortex contributes. These results suggest that brain connectivity is an excellent approach in predicting movement intention.

The Dependency Axiom and the Relation between Agreement and Movement

Science.gov (United States)

Linares Scarcerieau, Carlo Andrei

2012-01-01

Agreement and movement go hand in hand in a number of constructions across languages, and this correlation has played an important role in syntactic theory. The current standard approach to this "movement-agreement connection" is the Agree+EPP model, whose EPP component has often been questioned on conceptual grounds. The goal of this…

Magnetohydrodynamic equilibrium of axisymmetric systems with toroidal rotation

International Nuclear Information System (INIS)

Mansur, N.L.P.

1986-01-01

A model for studying magnetohydrodynamic equilibrium of axisymetrically confined plasma with toroidal rotation, extended to the Grad. Shafranov equation is presented. The expression used for the scalar pressure is modifiec, and the influence of toroidal magnetic field is included, The equation for general motion of axisymetrically confined plasma, particularizing for rotation movements is described. Two cases are compared: one supposes the entropy as a function of poloidal magnetic flux and other supposes the temperature as a function of flux. The equations for these two cases obtaining a simplified expression by others approximations are established. The proposed model is compared with Shibata model, which uses density as function of flux, and with the ideal spheromak model. A set of cases taking in account experimental data is studied. (M.C.K.) [pt

Are altered smooth pursuit eye movements related to chronic pain and disability following whiplash injuries? A prospective trial with one-year follow-up.

Science.gov (United States)

Kongsted, Alice; Jørgensen, Lars Vincents; Leboeuf-Yde, Charlotte; Qerama, Erisela; Korsholm, Lars; Bendix, Tom

2008-05-01

To evaluate the ability of early smooth pursuit testing to predict chronic whiplash-associated disorders, and to study whether the presence of abnormal smooth pursuit eye movements at one-year follow-up is associated with symptoms at that time. Prospective cohort study with one-year follow-up. The study was carried out at a university research centre and participants were recruited from emergency units and general practitioners. In all, 262 participants were recruited within 10 days from a whiplash injury. Smooth pursuit eye movements were tested with electrooculography (EOG) an average of 12 days after a whiplash trauma and again after one year. Analyses of EOG recordings were computerized. Associations between test results both from baseline and one-year tests and self-reported neck pain, headache, neck disability and working ability one year after the car collision were determined. Results of early eye movement tests were not associated with the prognosis. Reduced smooth pursuit performance when tested in static cervical rotation at the one-year follow-up was significantly associated with higher neck pain intensity at that time (regression coefficient 0.8, 95% confidence interval (CI) 0.04-1.5), but the association was too weak for the test to discriminate between recovered participants and those with lasting symptoms. Although reduced smooth pursuit performance at one-year follow-up was associated with persistent neck pain, smooth pursuit eye movement tests are not useful as predictive or diagnostic tests in whiplash-associated disorders.

The rotation of P/Halley

International Nuclear Information System (INIS)

Sagdeev, R.Z.; Szegoe, K.; Kondor, A.; Merenyi, E.; Smith, B.A.; Larson, S.; Toth, I.

1987-11-01

The nucleus of the comet Halley rotates as a slightly asymmetric top, the orientation of the rotation axis (the orientation of the angular momentum vector) is b=54 deg +-15 deg, l=219 deg +-15 deg in the ecliptic system. In the case of the rotation of an asymmetric top the rotation axis is not fixed rigidly to the body, which means that while the nucleus rotates around the axis with a period of 2.2+-0.05 d, its long axis 'nods' periodically with a period of 7.4+-0.05 d. The amplitude of the 'nodding' is about 15 deg +-3 deg in both directions relative to a plane perpendicular to the rotation axis. (author) 21 refs.; 6 figs.; 2 tabs

Arthroscopic suture bridge rotator cuff repair: functional outcome, repair integrity, and preoperative factors related to postoperative outcome.

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Rimmke, Nathan; Maerz, Tristan; Cooper, Ross; Yadavalli, Sailaja; Anderson, Kyle

2016-01-01

To assess the retear rate, retear size and location, the clinical impact of a retear, and preoperative patient factors related to postoperative outcome after arthroscopic suture bridge rotator cuff repair. Fifty six patients with an isolated, full-thickness supraspinatus tendon tear who underwent arthroscopic suture bridge rotator cuff repair were retrospectively identified. Patients were evaluated and rotator cuff integrity was assessed using ultrasonography. Visual analog score (VAS), the American Shoulder and Elbow Surgeon (ASES) score, shoulder range of motion and strength were used for clinical evaluation. Retears were assessed for size and location on ultrasonography. Forty two patients (75%) aged a mean 59.7 ± 8.6 years (range 41-79 years) were available for follow-up at a mean 13.5 months. Postoperative evaluation indicated significant improvements in ASES score (49.76 ± 18.2 to 86.57 ± 13.4, P rotation ROM (44.13° ± 12.0 to 52.09° ± 12.0, P = 0.003). The retear rate was 14.28% (6/42). Patients with retears were not older (P = 0.526) but had a larger preoperative tear size (3.25 cm ± 0.5 vs. 2.05 cm ± 0.48, P rotation ROM (P = 0.002), and internal rotation strength (P = 0.004). Arthroscopic suture bridge repair provides good clinical results with a low retear rate. The duration of preoperative symptoms was associated with postoperative outcome, indicating that delaying surgery may result in inferior outcomes. IV, Case Series.

Cystic Lesions in the Greater Tuberosity of the Humerus: The Relation to Rotator Cuff Tears and Age

Energy Technology Data Exchange (ETDEWEB)

Kim, Gang Deuk; Oh, Jung Taek [Wonkwang University Hospital, Iksan (Korea, Republic of)

2008-12-15

This study was designed to investigate the location of cystic lesions in the greater tuberosity of the humerus and the relationship to rotator cuff tears and age. A total of 78 patients (age range, 19-82 years; mean age, 51 years) who underwent arthroscopy or open surgery after MR arthrography (MRA) for a painful shoulder were enrolled in the study. The location of the cystic lesions were classified as 'A' for a supraspinatus insertion site, as 'C' for an infraspinatus insertion site, as 'B' for both a supraspinatus and infraspinatus insertion site, as 'BG' for a site posterior to the bicipital groove and as 'P' for a site at the bare area of the humeral head. The location of cystic lesions and supraspinatus and infraspinatus tears were evaluated on MRA. Statistical analyses used the chi-squared test and logistic regression. 'BG' and 'A' cystic lesions were related to the presence of a supraspinatus tear, 'C' cystic lesions were related to the presence of an infraspinatus tear and 'B' cystic lesions were related to the presence of both supraspinatus and infraspinatus tears (p < 0.05). 'P' cystic lesions were not related to the presence of rotator cuff tears. The incidence of cystic lesions increased with age, but with no statistical correlation. Cystic lesions at the supraspinatus and infraspinatus insertion sites are useful to predict the presence of a rotator cuff tear, but cystic lesions were not age related

The Relation between Reading Skills and Eye Movement Patterns in Adolescent Readers: Evidence from a Regular Orthography.

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Magdalena Krieber

Full Text Available Over the past decades, the relation between reading skills and eye movement behavior has been well documented in English-speaking cohorts. As English and German differ substantially with regard to orthographic complexity (i.e. grapheme-phoneme correspondence, we aimed to delineate specific characteristics of how reading speed and reading comprehension interact with eye movements in typically developing German-speaking (Austrian adolescents. Eye movements of 22 participants (14 females; mean age = 13;6 years;months were tracked while they were performing three tasks, namely silently reading words, texts, and pseudowords. Their reading skills were determined by means of a standardized German reading speed and reading comprehension assessment (Lesegeschwindigkeits- und -verständnistest für Klassen 6-12. We found that (a reading skills were associated with various eye movement parameters in each of the three reading tasks; (b better reading skills were associated with an increased efficiency of eye movements, but were primarily linked to spatial reading parameters, such as the number of fixations per word, the total number of saccades and saccadic amplitudes; (c reading speed was a more reliable predictor for eye movement parameters than reading comprehension; (d eye movements were highly correlated across reading tasks, which indicates consistent reading performances. Contrary to findings in English-speaking cohorts, the reading skills neither consistently correlated with temporal eye movement parameters nor with the number or percentage of regressions made while performing any of the three reading tasks. These results indicate that, although reading skills are associated with eye movement patterns irrespective of language, the temporal and spatial characteristics of this association may vary with orthographic consistency.

Functional Movement Screen (FMS - kompleksowy system oceny funkcjonalnej pacjenta = Functional Movement Screen (FMS - a comprehensive system for the functional evaluation of the patient

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Bartosz Kochański

2015-04-01

4 Wydział Kultury Fizycznej, Zdrowia i Turystyki, Uniwersytet Kazimierza Wielkiego w Bydgoszczy, Polska   Streszczenie   System oceny funkcjonalnej - Functional Movement Screen (FMS został stworzony przez Graya Cooka oraz Lee Burtona w 1995 roku. FMS jest koncepcją, która umożliwia kompleksową analizę jakości podstawowych wzorców ruchowych, ocenę ryzyka kontuzji oraz stwierdzenie istnienia ograniczeń i asymetrii. Test FMS złożony jest z 7 prób (głęboki przysiad, przeniesienie kończyny dolnej nad płotkiem, przysiad w wykroku, ruchomość obręczy barkowej, aktywne uniesienie wyprostowanej kończyny dolnej, ugięcie ramion w podporze, stabilność rotacyjna tułowia. W pracy zaprezentowano test Functional Movement Screen, jako kompleksowy system oceny funkcjonalnej pacjenta.   Słowa kluczowe: Functional Movement Screen, FMS, ocena funkcjonalna, rehabilitacja.   Abstract   Functional Movement Screen (FMS was created by Gray Cook and Lee Burton in 1995. FMS is a concept that allows comprehensive analysis of the quality of basic movement patterns, risk assessment and finding of injury to the limitations and asymmetries. FMS test consists of 7 samples (deep squat, hurdle step, in-line lunge, shoulder mobility, active straight leg raise, trunk stability push up, rotational stability. The paper presents the Functional Movement Screen test, as a comprehensive system of functional assessment of the patient.   Key words: Functional Movement Screen, FMS, functional assessment, rehabilitation.

Nystagmus responses in a group of normal humans during earth-horizontal axis rotation

Science.gov (United States)

Wall, Conrad, III; Furman, Joseph M. R.

1989-01-01

Horizontal eye movement responses to earth-horizontal yaw axis rotation were evaluated in 50 normal human subjects who were uniformly distributed in age (20-69 years) and each age group was then divided by gender. Subjects were rotated with eyes open in the dark, using clockwise and counter-clockwise 60 deg velocity trapezoids. The nystagmus slow component velocity is analyzed. It is shown that, despite large intersubject variability, parameters which describe earth-horizontal yaw axis responses are loosely interrelated, and some of them vary significantly with gender and age.

Triaxial energy relation to describe rotational band in 98-112Ru nuclei

International Nuclear Information System (INIS)

Singh, Yuvraj; Gupta, K.K.; Bihari, Chhail; Varshney, A.K.; Varshney, Mani; Singh, M.; Gupta, D.K.

2010-01-01

In a broader perspective rotation vibration coupling parameter (b) is considered changing with the change in excitation energy (ε 1 ) and is evaluated on fitting experimental energy for 98-112 Ru isotopes in the frame work of general asymmetric rotor model. The moment of inertia parameter (a), common to yrast and quasi-γ band, is calculated from deformation parameter (β) using general empirical relation. The present work is undertaken to suggest some suitable equation for the trajectories which are similar in shape in 98-112 Ru nuclei

Rotational Angles and Velocities During Down the Line and Diagonal Across Court Volleyball Spikes

OpenAIRE

Justin R. Brown; Bader J. Alsarraf; Mike Waller; Patricia Eisenman; Charlie A. Hicks-Little

2014-01-01

The volleyball spike is an explosive movement that is frequently used to end a rally and earn a point. High velocity spikes are an important skill for a successful volleyball offense. Although the influence of vertical jump height and arm velocity on spiked ball velocity (SBV) have been investigated, little is known about the relationship of shoulder and hip angular kinematics with SBV. Other sport skills, like the baseball pitch share similar movement patterns and suggest trunk rotation is i...

Lifestyle and metabolic factors in relation to shoulder pain and rotator cuff tendinitis: a population-based study.

Science.gov (United States)

Rechardt, Martti; Shiri, Rahman; Karppinen, Jaro; Jula, Antti; Heliövaara, Markku; Viikari-Juntura, Eira

2010-07-20

Shoulder pain is a common health problem. The purpose of this study was to assess the associations of lifestyle factors, metabolic factors and carotid intima-media thickness with shoulder pain and chronic (> 3 months) rotator cuff tendinitis. In this cross-sectional study, the target population consisted of subjects aged 30 years or older participating in a national Finnish Health Survey during 2000-2001. Of the 7,977 eligible subjects, 6,237 (78.2%) participated in a structured interview and clinical examination. Chronic rotator cuff tendinitis was diagnosed clinically. Weight-related factors, C-reactive protein and carotid intima-media thickness were measured. The prevalence of shoulder joint pain during the preceding 30 days was 16% and that of chronic rotator cuff tendinitis 2.8%. Smoking, waist circumference and waist-to-hip ratio were related to an increased prevalence of shoulder pain in both genders. Metabolic syndrome, type 2 diabetes mellitus and carotid intima-media thickness were associated with shoulder pain in men, whereas high level of C-reactive protein was associated with shoulder pain in women. Increased waist circumference and type 1 diabetes mellitus were associated with chronic rotator cuff tendinitis in men. Our findings showed associations of abdominal obesity, some other metabolic factors and carotid intima-media thickness with shoulder pain. Disturbed glucose metabolism and atherosclerosis may be underlying mechanisms, although not fully supported by the findings of this study. Prospective studies are needed to further investigate the role of lifestyle and metabolic factors in shoulder disorders.

Corolla chirality does not contribute to directed pollen movement in Hypericum perforatum (Hypericaceae): mirror image pinwheel flowers function as radially symmetric flowers in pollination.

Science.gov (United States)

Diller, Carolina; Fenster, Charles B

2016-07-01

Corolla chirality, the pinwheel arrangement of petals within a flower, is found throughout the core eudicots. In 15 families, different chiral type flowers (i.e., right or left rotated corolla) exist on the same plant, and this condition is referred to as unfixed/enantiomorphic corolla chirality. There are no investigations on the significance of unfixed floral chirality on directed pollen movement even though analogous mirror image floral designs, for example, enantiostyly, has evolved in response to selection to direct pollinator and pollen movement. Here, we examine the role of corolla chirality on directing pollen transfer, pollinator behavior, and its potential influence on disassortative mating. We quantified pollen transfer and pollinator behavior and movement for both right and left rotated flowers in two populations of Hypericum perforatum. In addition, we quantified the number of right and left rotated flowers at the individual level. Pollinators were indifferent to corolla chirality resulting in no difference in pollen deposition between right and left flowers. Corolla chirality had no effect on pollinator and pollen movement between and within chiral morphs. Unlike other mirror image floral designs, corolla chirality appears to play no role in promoting disassortative mating in this species.

Development and performance of a new prosthesis system using ultrasonic sensor for wrist movements: a preliminary study

Science.gov (United States)

2014-01-01

Background The design and performance of a new development prosthesis system known as biomechatronics wrist prosthesis is presented in this paper. The prosthesis system was implemented by replacing the Bowden tension cable of body powered prosthesis system using two ultrasonic sensors, two servo motors and microcontroller inside the prosthesis hand for transradial user. Methods The system components and hand prototypes involve the anthropometry, CAD design and prototyping, biomechatronics engineering together with the prosthetics. The modeler construction of the system develop allows the ultrasonic sensors that are placed on the shoulder to generate the wrist movement of the prosthesis. The kinematics of wrist movement, which are the pronation/supination and flexion/extension were tested using the motion analysis and general motion of human hand were compared. The study also evaluated the require degree of detection for the input of the ultrasonic sensor to generate the wrist movements. Results The values collected by the vicon motion analysis for biomechatronics prosthesis system were reliable to do the common tasks in daily life. The degree of the head needed to bend to give the full input wave was about 45° - 55° of rotation or about 14 cm – 16 cm. The biomechatronics wrist prosthesis gave higher degree of rotation to do the daily tasks but did not achieve the maximum degree of rotation. Conclusion The new development of using sensor and actuator in generating the wrist movements will be interesting for used list in medicine, robotics technology, rehabilitations, prosthetics and orthotics. PMID:24755242

Predicting Functional Recovery in Chronic Stroke Rehabilitation Using Event-Related Desynchronization-Synchronization during Robot-Assisted Movement

Directory of Open Access Journals (Sweden)

Marco Caimmi

2016-01-01

Full Text Available Although rehabilitation robotics seems to be a promising therapy in the rehabilitation of the upper limb in stroke patients, consensus is still lacking on its additive effects. Therefore, there is a need for determining the possible success of robotic interventions on selected patients, which in turn determine the necessity for new investigating instruments supporting the treatment decision-making process and customization. The objective of the work presented in this preliminary study was to verify that fully robot assistance would not affect the physiological oscillatory cortical activity related to a functional movement in healthy subjects. Further, the clinical results following the robotic treatment of a chronic stroke patient, who positively reacted to the robotic intervention, were analyzed and discussed. First results show that there is no difference in EEG activation pattern between assisted and no-assisted movement in healthy subjects. Even more importantly, the patient’s pretreatment EEG activation pattern in no-assisted movement was completely altered, while it recovered to a quasi-physiological one in robot-assisted movement. The functional improvement following treatment was large. Using pretreatment EEG recording during robot-assisted movement might be a valid approach to assess the potential ability of the patient for recovering.

Influence of axial movement on fatigue of ProFile Ni-Ti rotary instruments: an in vitro evaluation.

Science.gov (United States)

Avoaka, Marie-Chantal; Haïkel, Youssef

2010-05-01

The aim of this study was to evaluate the influence of the axial movement and the angle of curve (in degrees) on fatigue of nickel-titanium (Ni-Ti) ProFile rotary endodontic instruments. Ni-Ti ProFile rotary instruments (Maillefer SA, Ballaigues, Switzerland), 25 mm long in the range of ISO size 15 to 40 with two tapers (0.4 and 0.6) were evaluated. They are divided in two groups: the instruments with axial movement and those without axial movement. The system used to test the fatigue is maintained in mechanical conditions as close as possible to the clinical situation. The axial movement is in the order of 2 mm in corono-apical direction with a frequency of 1 Hz. The concave radii incorporating a notched V-form for guiding the instruments were: 5; 7,5 and 10 mm. The rotary system is mounted on an electric handpiece and rotated at 350 rpm speed as recommended by the manufacturers. The instruments are rotated until their separation, and the time, in seconds, is recorded. Statistical evaluation is undertaken using a two-way t-test to identify significant differences between variables in the study (p engine drive ProFile instruments incorporating an axial movement and the instruments without axial movement with the same radius of curvature, size and taper.The incorporation of the axial movement increases significantly the life-span of the ProFile rotary instruments. This should reduce the risk of the instrument separation during the endodontic treatment.

Relativistic rotation and the anholonomic object

International Nuclear Information System (INIS)

Corum, J.F.

1977-01-01

The purpose of this communication is to call attention to the conceptual economy provided by the object of anholonomity for the theory of relativity. This geometric object expresses certain consequences of relativity theory and provides a single, simple framework for discussing a variety of phenomena. It particularly clarifies the description of relativistic rotation. The relativistic rotational transformation of the four coordinate differentials of flat space--time generates a set of anholonomic, or inexact differentials, whose duals are an orthogonal set of basis vectors. How should a rotating observer interpret physical events referred to such orthogonal, but anholonomic frames The answer to this question rests upon the origin and physical significance of the object of anholonomity. It is demonstrated that not only is the rotational Lorentz transformation an anholonomic transformation, but that the intrinsic anholonomic effects are essential to interpreting rotational phenomena. In particular, the Sagnac effect may be interpreted as the physical manifestation of temporal anholonomity under rotation. The Thomas precession of a reference axis may be interpreted as a consequence of the spatial anholonomity of the rotating frame. Further, the full four-dimensional covariance of Maxwellian electrodynamics, under a relativistic Lorentz rotation, is possible only with the inclusion of anholonomic effects. The anholonomic approach clarifies the distinction between the physically different operations of source rotation and observer rotation in a flat space--time. It is finally concluded that a consistant theory of relativistic rotation, satisfying the principle of general covariance, inherently requires the presence of the object of anholonomity

Precision grip responses to unexpected rotational perturbations scale with axis of rotation.

Science.gov (United States)

De Gregorio, Michael; Santos, Veronica J

2013-04-05

It has been established that rapid, pulse-like increases in precision grip forces ("catch-up responses") are elicited by unexpected translational perturbations and that response latency and strength scale according to the direction of linear slip relative to the hand as well as gravity. To determine if catch-up responses are elicited by unexpected rotational perturbations and are strength-, axis-, and/or direction-dependent, we imposed step torque loads about each of two axes which were defined relative to the subject's hand: the distal-proximal axis away from and towards the subject's palm, and the grip axis which connects the two fingertips. Precision grip responses were dominated initially by passive mechanics and then by active, unimodal catch-up responses. First dorsal interosseous activity, marking the start of the catch-up response, began 71-89 ms after the onset of perturbation. The onset latency, shape, and duration (217-231 ms) of the catch-up response were not affected by the axis, direction, or magnitude of the rotational perturbation, while strength was scaled by axis of rotation and slip conditions. Rotations about the grip axis that tilted the object away from the palm and induced rotational slip elicited stronger catch-up responses than rotations about the distal-proximal axis that twisted the object between the digits. To our knowledge, this study is the first to investigate grip responses to unexpected torque loads and to show characteristic, yet axis-dependent, catch-up responses for conditions other than pure linear slip. Copyright © 2013 Elsevier Ltd. All rights reserved.

Type Synthesis of Parallel Mechanisms with the First Class GF Sets and Two-Dimensional Rotations

Directory of Open Access Journals (Sweden)

Jialun Yang

2012-09-01

Full Text Available The novel design of parallel mechanisms plays a key role in the potential application of parallel mechanisms. In this paper, the type synthesis of parallel mechanisms with the first class GF sets and two-dimensional rotations is studied. The rule of two-dimensional rotations is given, which lays the theoretical foundation for the intersection operations of specific GF sets. Next, kinematic limbs with specific characteristics are designed according to the 2-D and 3-D axes movement theorems. Finally, several synthesized parallel mechanisms with the first class GF sets and two-dimensional rotations are illustrated to show the effectiveness of the proposed methodology.

Bidirectional optical rotation of cells

Directory of Open Access Journals (Sweden)

Jiyi Wu

2017-08-01

Full Text Available Precise and controlled rotation manipulation of cells is extremely important in biological applications and biomedical studies. Particularly, bidirectional rotation manipulation of a single or multiple cells is a challenge for cell tomography and analysis. In this paper, we report an optical method that is capable of bidirectional rotation manipulation of a single or multiple cells. By launching a laser beam at 980 nm into dual-beam tapered fibers, a single or multiple cells in solutions can be trapped and rotated bidirectionally under the action of optical forces. Moreover, the rotational behavior can be controlled by altering the relative distance between the two fibers and the input optical power. Experimental results were interpreted by numerical simulations.

Asteroseismology of Red-Giant Stars: Mixed Modes, Differential Rotation, and Eccentric Binaries

Science.gov (United States)

Beck, Paul G.

2013-12-01

Astronomers are aware of rotation in stars since Galileo Galilei attributed the movement of sunspots to rotation of the Sun in 1613. In contrast to the Sun, whose surface can be resolved by small telescopes or even the (protected) eye, we detect stars as point sources with no spatial information. Numerous techniques have been developed to derive information about stellar rotation. Unfortunately, most observational data allow only for the surface rotational rate to be inferred. The internal rotational profile, which has a great effect on the stellar structure and evolution, remains hidden below the top layers of the star - the essential is hidden to the eyes. Asteroseismology allows us to "sense" indirectly deep below the stellar surface. Oscillations that propagate through the star provide information about the deep stellar interiors while they also distort the stellar surface in characteristic patterns leading to detectable brightness or velocity variations. Also, certain oscillation modes are sensitive to internal rotation and carry information on how the star is spinning deep inside. Thanks to the unprecedented quality of NASA's space telescope Kepler, numerous detailed observations of stars in various evolutionary stages are available. Such high quality data allow that for many stars, rotation can not only be constrained from surface rotation, but also investigated through seismic studies. The work presented in this thesis focuses on the oscillations and internal rotational gradient of evolved single and binary stars. It is shown that the seismic analysis can reach the cores of oscillating red-giant stars and that these cores are rapidly rotating, while nested in a slowly rotating convective envelope.

Exact solutions for rotating charged dust

International Nuclear Information System (INIS)

Islam, J.N.

1984-01-01

Earlier work by the author on rotating charged dust is summarized. An incomplete class of exact solutions for differentially rotating charged dust in Newton-Maxwell theory for the equal mass and charge case that was found earlier is completed. A new global exact solution for cylindrically symmetric differentially rotating charged dust in Newton-Maxwell theory is presented. Lastly, a new exact solution for cylindrically symmetric rigidly rotating charged dust in general relativity is given. (author)

Involvement of the intrinsic/default system in movement-related self recognition.

Science.gov (United States)

Salomon, Roy; Malach, Rafael; Lamy, Dominique

2009-10-21

The question of how people recognize themselves and separate themselves from the environment and others has long intrigued philosophers and scientists. Recent findings have linked regions of the 'default brain' or 'intrinsic system' to self-related processing. We used a paradigm in which subjects had to rely on subtle sensory-motor synchronization differences to determine whether a viewed movement belonged to them or to another person, while stimuli and task demands associated with the "responded self" and "responded other" conditions were precisely matched. Self recognition was associated with enhanced brain activity in several ROIs of the intrinsic system, whereas no differences emerged within the extrinsic system. This self-related effect was found even in cases where the sensory-motor aspects were precisely matched. Control conditions ruled out task difficulty as the source of the differential self-related effects. The findings shed light on the neural systems underlying bodily self recognition.

Spatial Coding of Eye Movements Relative to Perceived Orientations During Roll Tilt with Different Gravitoinertial Loads

Science.gov (United States)

Wood, Scott; Clement, Gilles

2013-01-01

This purpose of this study was to examine the spatial coding of eye movements during roll tilt relative to perceived orientations while free-floating during the microgravity phase of parabolic flight or during head tilt in normal gravity. Binocular videographic recordings obtained in darkness from six subjects allowed us to quantify the mean deviations in gaze trajectories along both horizontal and vertical coordinates relative to the aircraft and head orientations. Both variability and curvature of gaze trajectories increased during roll tilt compared to the upright position. The saccades were less accurate during parabolic flight compared to measurements obtained in normal gravity. The trajectories of saccades along perceived horizontal orientations tended to deviate in the same direction as the head tilt, while the deviations in gaze trajectories along the perceived vertical orientations deviated in the opposite direction relative to the head tilt. Although subjects were instructed to look off in the distance while performing the eye movements, fixation distance varied with vertical gaze direction independent of whether the saccades were made along perceived aircraft or head orientations. This coupling of horizontal vergence with vertical gaze is in a consistent direction with the vertical slant of the horopter. The increased errors in gaze trajectories along both perceived orientations during microgravity can be attributed to the otolith's role in spatial coding of eye movements.

Effectively universal behavior of rotating neutron stars in general relativity makes them even simpler than their Newtonian counterparts.

Science.gov (United States)

Pappas, George; Apostolatos, Theocharis A

2014-03-28

Recently, it was shown that slowly rotating neutron stars exhibit an interesting correlation between their moment of inertia I, their quadrupole moment Q, and their tidal deformation Love number λ (the I-Love-Q relations), independently of the equation of state of the compact object. In the present Letter a similar, more general, universality is shown to hold true for all rotating neutron stars within general relativity; the first four multipole moments of the neutron star are related in a way independent of the nuclear matter equation of state we assume. By exploiting this relation, we can describe quite accurately the geometry around a neutron star with fewer parameters, even if we don't know precisely the equation of state. Furthermore, this universal behavior displayed by neutron stars could promote them to a more promising class of candidates (next to black holes) for testing theories of gravity.

Receptive Vocabulary Knowledge in Low-Functioning Autism as Assessed by Eye Movements, Pupillary Dilation, and Event-Related Potentials

Science.gov (United States)

2013-06-01

screening questionnaire for Asperger Syndrome and other high-functioning autism spectrum disorders in school age children. Journal of Autism ...Award Number: W81XWH-10-1-0404 TITLE: Receptive Vocabulary Knowledge in Low-Functioning Autism as Assessed by Eye Movements, Pupillary...Knowledge in Low-Functioning Autism as Assessed by Eye- Movements, Pupillary Dilation, and Event-Related Potentials 5b. GRANT NUMBER W81XWH-10-1-0404

A dissipative model of solar system and stability of stationary rotations

Science.gov (United States)

Vilke, V. G.

2009-04-01

In classical model of Solar system the planets are represented by the material points cooperating under the law of universal gravitation. This model remains fair if planet to consider as absolutely rigid spheres with spherical distribution of density. The gravitational potential of such body coincides with potential of a material point, and rotation of each sphere concerning his centre of mass occurs to constant angular velocity. The motion of the centers of mass of spherical planets identically to motion in the appropriate problem of points. Let's notice, that forms of planets of Solar system are close to spherical as dominant forces at formation of planets are gravitational forces to which forces of molecular interaction in substance of a planet counteract. The model of the isolated Solar system submitted in a not indignant condition by homogeneous viscoelastic spheres is considered. Under action of own rotation and tidal gravitational forces the spherical planet changes the shape: there is "flattening" of a planet in a direction of a vector of its angular velocity and formation of tidal bulgs on the lines connecting the centre of a planet with the centers of other planets. From a variational principle of Hamilton the full system of the equations describing movements of the centers of mass of planets, rotations of systems of coordinates, by integrated image connected with planets, and deformations of planets be relative these of systems of coordinates has been obtained. It is supposed, that tidal gravitational, centrifugal and elastic forces result in small change of the spherical form of a planet. In system there are small parameters - inversely proportional of the Young modules of materials of the planets, providing small deformations of planets at influence on them of the centrifugal forces produced by own rotation of planets, and the small tidal deformations arising under influence of gradients of gravitational forces. The method of division of movements

Two different motor learning mechanisms contribute to learning reaching movements in a rotated visual environment [version 2; referees: 2 approved, 1 approved with reservations

Directory of Open Access Journals (Sweden)

Virginia Way Tong Chu

2014-12-01

Full Text Available Practice of movement in virtual-reality and other artificially altered environments has been proposed as a method for rehabilitation following neurological injury and for training new skills in healthy humans.  For such training to be useful, there must be transfer of learning from the artificial environment to the performance of desired skills in the natural environment.  Therefore an important assumption of such methods is that practice in the altered environment engages the same learning and plasticity mechanisms that are required for skill performance in the natural environment.  We test the hypothesis that transfer of learning may fail because the learning and plasticity mechanism that adapts to the altered environment is different from the learning mechanism required for improvement of motor skill.  In this paper, we propose that a model that separates skill learning and environmental adaptation is necessary to explain the learning and aftereffects that are observed in virtual reality experiments.  In particular, we studied the condition where practice in the altered environment should lead to correct skill performance in the original environment. Our 2-mechanism model predicts that aftereffects will still be observed when returning to the original environment, indicating a lack of skill transfer from the artificial environment to the original environment. To illustrate the model prediction, we tested 10 healthy participants on the interaction between a simple overlearned motor skill (straight hand movements to targets in different directions and an artificially altered visuomotor environment (rotation of visual feedback of the results of movement.  As predicted by the models, participants show adaptation to the altered environment and after-effects on return to the baseline environment even when practice in the altered environment should have led to correct skill performance.  The presence of aftereffect under all conditions that

Eye-movement patterns during nonsymbolic and symbolic numerical magnitude comparison and their relation to math calculation skills.

Science.gov (United States)

Price, Gavin R; Wilkey, Eric D; Yeo, Darren J

2017-05-01

A growing body of research suggests that the processing of nonsymbolic (e.g. sets of dots) and symbolic (e.g. Arabic digits) numerical magnitudes serves as a foundation for the development of math competence. Performance on magnitude comparison tasks is thought to reflect the precision of a shared cognitive representation, as evidence by the presence of a numerical ratio effect for both formats. However, little is known regarding how visuo-perceptual processes are related to the numerical ratio effect, whether they are shared across numerical formats, and whether they relate to math competence independently of performance outcomes. The present study investigates these questions in a sample of typically developing adults. Our results reveal a pattern of associations between eye-movement measures, but not their ratio effects, across formats. This suggests that ratio-specific visuo-perceptual processing during magnitude processing is different across nonsymbolic and symbolic formats. Furthermore, eye movements are related to math performance only during symbolic comparison, supporting a growing body of literature suggesting symbolic number processing is more strongly related to math outcomes than nonsymbolic magnitude processing. Finally, eye-movement patterns, specifically fixation dwell time, continue to be negatively related to math performance after controlling for task performance (i.e. error rate and reaction time) and domain general cognitive abilities (IQ), suggesting that fluent visual processing of Arabic digits plays a unique and important role in linking symbolic number processing to formal math abilities. Copyright © 2017 Elsevier B.V. All rights reserved.

The influence of vessel movements on the energy expenditure of fishermen in relation to activities and occupational tasks on board

DEFF Research Database (Denmark)

Breidahl, Tomas; Christensen, Michael; Jepsen, Jørgen Riis

2015-01-01

the activities carried out on board. This continuation of the study goes further by exploring the relation between the exposure to the ship’s movements and the fishermen’s energy expenditure during various physical activities on board. Materials and methods: Four fishermen on 2 contemporary steel trawlers...... demonstrated that vessel’s movements in calm weather increase the energy expenditure during navigation, fishing, and machine handling and that the relation differs in between these activities on board and rest.......Background: Previous studies of professional fishing activities have indicated that vessel movements correlate to fishermen’s energy expenditure. We have previously demonstrated that even in calm weather, the heel and pitch significantly increase the fishermen’s energy expenditure, ignoring...

Rotational effects on turbine blade cooling

Energy Technology Data Exchange (ETDEWEB)

Govatzidakis, G.J.; Guenette, G.R.; Kerrebrock, J.L. [Massachusetts Institute of Technology, Cambridge, MA (United States)

1995-10-01

An experimental investigation of the influence of rotation on the heat transfer in a smooth, rectangular passage rotating in the orthogonal mode is presented. The passage simulates one of the cooling channels found in gas turbine blades. A constant heat flux is imposed on the model with either inward or outward flow. The effects of rotation and buoyancy on the Nusselt number were quantified by systematically varying the Rotation number, Density Ratio, Reynolds number, and Buoyancy parameter. The experiment utilizes a high resolution infrared temperature measurement technique in order to measure the wall temperature distribution. The experimental results show that the rotational effects on the Nusselt number are significant and proper turbine blade design must take into account the effects of rotation, buoyancy, and flow direction. The behavior of the Nusselt number distribution depends strongly on the particular side, axial position, flow direction, and the specific range of the scaling parameters. The results show a strong coupling between buoyancy and Corollas effects throughout the passage. For outward flow, the trailing side Nusselt numbers increase with Rotation number relative to stationary values. On the leading side, the Nusselt numbers tended to decrease with rotation near the inlet and subsequently increased farther downstream in the passage. The Nusselt numbers on the side walls generally increased with rotation. For inward flow, the Nusselt numbers generally improved relative to stationary results, but increases in the Nusselt number were relatively smaller than in the case of outward flow. For outward and inward flows, increasing the density ratio generally tended to decrease Nusselt numbers on the leading and trailing sides, but the exact behavior and magnitude depended on the local axial position and specific range of Buoyancy parameters.

Further Study of Λ-Related Quantum Interference of Π-State Diatomic on Collision-Induced Rotational Energy Transfer

International Nuclear Information System (INIS)

Li Yongqing; Song Peng; Chen Yuehui; Wang Weili; Ma Fengcai

2005-01-01

In our previous theoretical studies [Meng-Tao Sun, Yong-Qing Lee, and Feng-Cai Ma, Chem. Phys. Lett. 371 (2003) 342], we have reported the quantum interference on collision-induced rotational energy transfer on CO (A 1 Π, v = 3) with inert gases, which originates from the difference between the two Λ-related collision potential energy surfaces. The interference angle, which measures the degree of coherence, is presented in this paper. Based on the time-dependent first order Born approximation, taking into account the anisotropic Lennard-Jones interaction potentials, the relation of the interference angle with the factors, including experimental temperature, partner, and rotational quantum number, are obtained. The changing tendencies with them are discussed. This theoretical model is important to understanding and performing this kind of experiment.

Effect of Relative Movement between the Shroud and Blade on Tip Leakage Flow Characteristics

Directory of Open Access Journals (Sweden)

Xiaochun Wang

2017-10-01

Full Text Available An experimental and numerical investigation into the tip leakage flow of a turbine rotor is carried out using a particle image velocimetry (PIV system and the commercial software ANSYS CFX 14.0. The specimen used in this work is a typical GE-E3 model with a new squealer tip design. The experimental data are used to create a turbulence model and numerical strategy. Through the validated turbulence model and numerical strategy, simulations are carried out to compare the characteristics of the tip leakage flow in three cases: (1 the blade is rotating, but the shroud is stationary, which is the real status of turbine rotor operation; (2 the blade is stationary, but the shroud moves, to simulate their relative movement; (3 the blade is stationary, and the shroud is also stationary, this is a simplified case, but has been widely used in the experiments on rotor tip leakage flow. Detailed analysis of the flow phenomena shows that the second case is a reasonable alternative approach to simulate the real state. However, the flow patterns in the third case exhibit some evident differences from the real status. These differences are caused by the inaccurate viscous force arising from the stationary blade and shroud. In this work, a modification method for the experiments conducted in the third case is firstly proposed, which is realized through adding an imaginary roughness at the shroud wall to be close to the real viscous effect, and to thereby reduce the deviation of the experiment from the real case. According to the results calculated by ANSYS CFX, the flow structure in the modification case is very close to the real status. Besides, this modification case is an easy and cheap way to simulate the real tip leakage flow.

The line copy task for kinesthesia and internal movement representation: application in children.

NARCIS (Netherlands)

Smits-Engelsman, B.C.M.; Duysens, J.E.J.

2008-01-01

In the present study a new test is proposed and tested, which requires ability to use information both from kinesthesia and from mental rotation of previously produced cyclic movements over a distinct trajectory. This Line Copy Test (LICT) was performed by 58 children aged 7-11 years. For the

Postural reconfiguration and cycle-to-cycle variability in patients with work-related musculoskeletal disorders compared to healthy controls and in relation to pain emerging during a repetitive movement task

NARCIS (Netherlands)

Longo, A.; Meulenbroek, R.G.J.; Haid, T.; Federolf, P.A.

2018-01-01

Background: Movement variability in sustained repetitive tasks is an important factor in the context of work-related musculoskeletal disorders. While a popular hypothesis suggests that movement variability can prevent overuse injuries, pain evolving during task execution may also cause variability.

Measurements of Drag Coefficients and Rotation Rates of Free-Falling Helixes

KAUST Repository

Al-Omari, Abdulrhaman A.

2016-05-01

The motion of bacteria in the environment is relevant to several fields. At very small scales and with simple helical shapes, we are able to describe experimentally and mathematically the motion of solid spirals falling freely within a liquid pool. Using these shapes we intend to mimic the motion of bacteria called Spirochetes. We seek to experimentally investigate the linear and the rotational motion of such shapes. A better understanding of the dynamics of this process will be practical not only on engineering and physics, but the bioscience and environmental as well. In the following pages, we explore the role of the shape on the motion of passive solid helixes in different liquids. We fabricate three solid helical shapes and drop them under gravity in water, glycerol and a mixture of 30% glycerol in water. That generated rotation due to helical angle in water. However, we observe the rotation disappear in glycerol. The movement of the solid helical shapes is imaged using a high-speed video camera. Then, the images are analyzed using the supplied software and a computer. Using these simultaneous measurements, we examine the terminal velocity of solid helical shapes. Using this information we computed the drag coefficient and the drag force. We obtain the helical angular velocity and the torque applied to the solid. The results of this study will allow us to more accurately predict the motion of solid helical shape. This analysis will also shed light onto biological questions of bacteria movement.

A compact rotating dilution refrigerator

Science.gov (United States)

Fear, M. J.; Walmsley, P. M.; Chorlton, D. A.; Zmeev, D. E.; Gillott, S. J.; Sellers, M. C.; Richardson, P. P.; Agrawal, H.; Batey, G.; Golov, A. I.

2013-10-01

We describe the design and performance of a new rotating dilution refrigerator that will primarily be used for investigating the dynamics of quantized vortices in superfluid 4He. All equipment required to operate the refrigerator and perform experimental measurements is mounted on two synchronously driven, but mechanically decoupled, rotating carousels. The design allows for relative simplicity of operation and maintenance and occupies a minimal amount of space in the laboratory. Only two connections between the laboratory and rotating frames are required for the transmission of electrical power and helium gas recovery. Measurements on the stability of rotation show that rotation is smooth to around 10-3 rad s-1 up to angular velocities in excess of 2.5 rad s-1. The behavior of a high-Q mechanical resonator during rapid changes in rotation has also been investigated.

A relation between the rotational g-factor and the electric dipole moment of a diatomic molecule

DEFF Research Database (Denmark)

Sauer, Stephan P. A.

1998-01-01

The relation between the rotational g-factor and the electric dipole moment of a diatomic molecule is investigated. An explicit expression for the irreducible nonadiabatic contribution in terms of excited electronic states is derived. The importance of this expression for the analysis of vibration...

Sex-specific lateralization of event-related potential effects during mental rotation of polygons.

Science.gov (United States)

Pellkofer, Julia; Jansen, Petra; Heil, Martin

2014-08-06

Mental rotation performance has been found to produce one of the largest sex differences in cognition. Many theories suggest that this effect should be accompanied by a sex difference in functional cerebral asymmetry, but empirical data are more than equivocal probably because of (a) the use of inappropriate stimuli and (b) insufficient power of most neurophysiological studies. Therefore, sex differences in mental rotation of polygons were investigated in 122 adults. Men outperformed women on mental rotation speed (as well as on response time and accuracy). On the basis of the electrophysiological brain correlates of mental rotation, we observed a bilateral brain activity for men, whereas women's brain activity was clearly lateralized toward the left hemisphere if and only if mental rotation was involved. Thus, sex differences in functional cerebral asymmetry can indeed be observed if appropriate stimuli are used in a sufficiently large sample.

Lifestyle and metabolic factors in relation to shoulder pain and rotator cuff tendinitis: A population-based study

Directory of Open Access Journals (Sweden)

Jula Antti

2010-07-01

Full Text Available Abstract Background Shoulder pain is a common health problem. The purpose of this study was to assess the associations of lifestyle factors, metabolic factors and carotid intima-media thickness with shoulder pain and chronic (> 3 months rotator cuff tendinitis. Methods In this cross-sectional study, the target population consisted of subjects aged 30 years or older participating in a national Finnish Health Survey during 2000-2001. Of the 7,977 eligible subjects, 6,237 (78.2% participated in a structured interview and clinical examination. Chronic rotator cuff tendinitis was diagnosed clinically. Weight-related factors, C-reactive protein and carotid intima-media thickness were measured. Results The prevalence of shoulder joint pain during the preceding 30 days was 16% and that of chronic rotator cuff tendinitis 2.8%. Smoking, waist circumference and waist-to-hip ratio were related to an increased prevalence of shoulder pain in both genders. Metabolic syndrome, type 2 diabetes mellitus and carotid intima-media thickness were associated with shoulder pain in men, whereas high level of C-reactive protein was associated with shoulder pain in women. Increased waist circumference and type 1 diabetes mellitus were associated with chronic rotator cuff tendinitis in men. Conclusions Our findings showed associations of abdominal obesity, some other metabolic factors and carotid intima-media thickness with shoulder pain. Disturbed glucose metabolism and atherosclerosis may be underlying mechanisms, although not fully supported by the findings of this study. Prospective studies are needed to further investigate the role of lifestyle and metabolic factors in shoulder disorders.

The effect of pre-cure bracket movement on shear bond strength during placement of orthodontic brackets, an in vitro study.

Science.gov (United States)

Tam, Byron; Bollu, Prashanti; Chaudhry, Kishore; Subramani, Karthikeyan

2017-10-01

The purpose of this study was to determine the influence of linear and rotational pre-cure bracket displacement during the bonding procedure on shear bond strength (SBS) of orthodontic brackets. Stainless steel orthodontic premolar brackets were bonded to the buccal surfaces of 50 human pre-molars with a conventional two-step bonding protocol. Extracted human pre-molars were divided into 5 groups (n=10/group). In the Control Group, the brackets were bonded with no pre-cure bracket displacement or rotation. The Rotation Group was bonded with 45 degrees of pre-cure rotation. The Displacement Group was bonded with 2mm pre-cure linear displacement. The Rotation-Displacement Group was bonded with pre-cure movements of 45º counter-clockwise rotation and 2mm displacement. The Slippage Group was bonded with 2mm each of mesial and distal pre-cure linear displacement. Photo-activation was carried out on the lateral sides of the bracket. Shear debonding force was measured, 24 hours after initial bonding, with an Instron universal testing machine using a knife-edged chisel. Data was analyzed using one-way ANOVA test. Adhesive Remnant Index (ARI) was scored under 15x magnification. The ARI data was analyzed using the Chi-square test ( p -value bracket displacements do not appear to effect the shear bond strength of orthodontic brackets. Key words: Shear bond strength, orthodontic bracket, displacement, rotation, adhesive remnant index, pre-cure movement.

Movements of adult Atlantic salmon in relation to a hydroelectric dam and fish ladder

International Nuclear Information System (INIS)

Gowans, A.R.D.; Priede, I.G.

1999-01-01

The movements of adult Atlantic salmon were recorded as they approached, entered and ascended the pool-and-orifice fish ladder at Pitlochry Dam, Scotland. Thirty-nine returning salmon were captured in the River Tummel by rod-and-line angling, radio-tagged and released near where they were caught. The subsequent movements of each fish were then monitored. An electronic fish counter collected additional data on movements of untagged fish past a fixed point in the ladder. Of the 39 fish that were radio-tagged, 29 individuals were recorded approaching and ascending the ladder. The remaining fish either did not approach the dam (three fish), approached the dam after detailed tracking had ended (two fish), were recaptured by anglers (three fish), or the radio tags failed (two fish). Salmon released earlier in the year delayed longer before first approaching the dam. Delays between first approaching the dam and ascent of the ladder were greater for fish that approached the dam earlier. The majority of salmon visited the ladder entrance more than once (maximum 10 visits) before ascending. Having entered, all but four salmon ascended the fish ladder successfully on their first attempt. The four individuals that failed to do so succeeded on their second attempt. The rate at which salmon ascended the ladder was related directly to temperature. The shortest ascent time of a radio-tagged salmon was 5.25 h. Movements of eight of 11 tagged fish through the ladder ceased with the onset of darkness but continued on the following morning. No radio-tagged fish entered the ladder at temperatures below 9 o C. Similarly, few untagged fish were recorded ascending the ladder by the electronic fish counter at water temperatures below 8.5 o C. Records from the fish counter indicated that 92% of upstream movements were made during daylight. (author)

Do axes of rotation change during fast and slow motions of the dominant and non-dominate arms?

Directory of Open Access Journals (Sweden)

Pagano Christopher

2011-12-01

Full Text Available The velocity-dependent change in rotational axes observed in the control of unconstrained 3D arm rotations for the dominant limb seems to conform to a minimum inertia resistance (MIR principle [4]. This is an efficient biomechanical solution that allows for the reduction of torques. We tested whether the MIR principle governs rotating movement when subjects were instructed to maintain the shoulder-elbow joint axis close to horizontal for both dominant and non dominant limbs. Subjects (n=12 performed externalinternal rotations of their arms in two angular positions (90° versus 150°, two angular velocities (slow (S versus fast (F, and in two sensory conditions (kinaesthetic (K versus visuo- kinaesthetic (VK. We expected more scattered displacements of the rotation axis employed for rotating the non dominant limb compared to the dominant limb. The results showed that the rotational axis of a multiarticulated limb coincided with SH-EL at S & F velocity for both arms.

Eye-movements and ongoing task processing.

Science.gov (United States)

Burke, David T; Meleger, Alec; Schneider, Jeffrey C; Snyder, Jim; Dorvlo, Atsu S S; Al-Adawi, Samir

2003-06-01

This study tests the relation between eye-movements and thought processing. Subjects were given specific modality tasks (visual, gustatory, kinesthetic) and assessed on whether they responded with distinct eye-movements. Some subjects' eye-movements reflected ongoing thought processing. Instead of a universal pattern, as suggested by the neurolinguistic programming hypothesis, this study yielded subject-specific idiosyncratic eye-movements across all modalities. Included is a discussion of the neurolinguistic programming hypothesis regarding eye-movements and its implications for the eye-movement desensitization and reprocessing theory.

Earth Rotation

Science.gov (United States)

Dickey, Jean O.

1995-01-01

The study of the Earth's rotation in space (encompassing Universal Time (UT1), length of day, polar motion, and the phenomena of precession and nutation) addresses the complex nature of Earth orientation changes, the mechanisms of excitation of these changes and their geophysical implications in a broad variety of areas. In the absence of internal sources of energy or interactions with astronomical objects, the Earth would move as a rigid body with its various parts (the crust, mantle, inner and outer cores, atmosphere and oceans) rotating together at a constant fixed rate. In reality, the world is considerably more complicated, as is schematically illustrated. The rotation rate of the Earth's crust is not constant, but exhibits complicated fluctuations in speed amounting to several parts in 10(exp 8) [corresponding to a variation of several milliseconds (ms) in the Length Of the Day (LOD) and about one part in 10(exp 6) in the orientation of the rotation axis relative to the solid Earth's axis of figure (polar motion). These changes occur over a broad spectrum of time scales, ranging from hours to centuries and longer, reflecting the fact that they are produced by a wide variety of geophysical and astronomical processes. Geodetic observations of Earth rotation changes thus provide insights into the geophysical processes illustrated, which are often difficult to obtain by other means. In addition, these measurements are required for engineering purposes. Theoretical studies of Earth rotation variations are based on the application of Euler's dynamical equations to the problem of finding the response of slightly deformable solid Earth to variety of surface and internal stresses.

Internal rotation of the Sun

International Nuclear Information System (INIS)

Duvall, T.L. Jr.; Goode, P.R.; Gouch, D.O.

1984-01-01

The frequency difference between prograde and retrograde sectoral solar oscillations is analysed to determine the rotation rate of the solar interior, assuming no latitudinal dependence. Much of the solar interior rotates slightly less rapidly than the surface, while the innermost part apparently rotates more rapidly. The resulting solar gravitational quadrupole moment is J 2 = (1.7 +- 0.4) x 10 -7 and provides a negligible contribution to current planetary tests of Einstein's theory of general relativity. (author)

INTERNAL-CYCLE VARIATION OF SOLAR DIFFERENTIAL ROTATION

International Nuclear Information System (INIS)

Li, K. J.; Xie, J. L.; Shi, X. J.

2013-01-01

The latitudinal distributions of the yearly mean rotation rates measured by Suzuki in 1998 and 2012 and Pulkkinen and Tuominen in 1998 are utilized to investigate internal-cycle variation of solar differential rotation. The rotation rate at the solar equator seems to have decreased since cycle 10 onward. The coefficient B of solar differential rotation, which represents the latitudinal gradient of rotation, is found to be smaller in the several years after the minimum of a solar cycle than in the several years after the maximum time of the cycle, and it peaks several years after the maximum time of the solar cycle. The internal-cycle variation of the solar rotation rates looks similar in profile to that of the coefficient B. A new explanation is proposed to address such a solar-cycle-related variation of the solar rotation rates. Weak magnetic fields may more effectively reflect differentiation at low latitudes with high rotation rates than at high latitudes with low rotation rates, and strong magnetic fields may more effectively repress differentiation at relatively low latitudes than at high latitudes. The internal-cycle variation is inferred as the result of both the latitudinal migration of the surface torsional pattern and the repression of strong magnetic activity in differentiation.

Movement-related and steady-state electromyographic activity of human elbow flexors in slow transition movements between two equilibrium states.

Science.gov (United States)

Tal'nov, A N; Cherkassky, V L; Kostyukov, A I

1997-08-01

The electromyograms were recorded in healthy human subjects by surface electrodes from the mm. biceps brachii (caput longum et. brevis), brachioradialis, and triceps brachii (caput longum) during slow transition movements in elbow joint against a weak extending torque. The test movements (flexion transitions between two steady-states) were fulfilled under visual control through combining on a monitor screen a signal from a joint angle sensor with a corresponding command generated by a computer. Movement velocities ranged between 5 and 80 degrees/s, subjects were asked to move forearm without activation of elbow extensors. Surface electromyograms were full-wave rectified, filtered and averaged within sets of 10 identical tests. Amplitudes of dynamic and steady-state components of the electromyograms were determined in dependence on a final value of joint angle, slow and fast movements were compared. An exponential-like increase of dynamic component was observed in electromyograms recorded from m. biceps brachii, the component had been increased with movement velocity and with load increment. In many experiments a statistically significant decrease of static component could be noticed within middle range of joint angles (40-60 degrees) followed by a well expressed increment for larger movements. This pattern of the static component in electromyograms could vary in different experiments even in the same subjects. A steady discharge in m. brachioradialis at ramp phase has usually been recorded only under a notable load. Variable and quite often unpredictable character of the static components of the electromyograms recorded from elbow flexors in the transition movements makes it difficult to use the equilibrium point hypothesis to describe the central processes of movement. It has been assumed that during active muscle shortening the dynamic components in arriving efferent activity should play a predominant role. A simple scheme could be proposed for transition to a

Jellyfish movement data - Determining Movement Patterns of Jellyfish

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This project is to determine horizontal and vertical movement patterns of two jellyfish species in Hood Canal, in relation to environmental variables. It is being...

Exploring pedestrian movement patterns

NARCIS (Netherlands)

Orellana, D.A.

2012-01-01

The main objective of this thesis is to develop an approach for exploring, analysing and interpreting movement patterns of pedestrians interacting with the environment. This objective is broken down in sub-objectives related to four research questions. A case study of the movement of visitors in a

Biology of biomechanics: Finite element analysis of a statically determinate system to rotate the occlusal plane for correction of a skeletal Class III open-bite malocclusion.

Science.gov (United States)

Roberts, W Eugene; Viecilli, Rodrigo F; Chang, Chris; Katona, Thomas R; Paydar, Nasser H

2015-12-01

In the absence of adequate animal or in-vitro models, the biomechanics of human malocclusion must be studied indirectly. Finite element analysis (FEA) is emerging as a clinical technology to assist in diagnosis, treatment planning, and retrospective analysis. The hypothesis tested is that instantaneous FEA can retrospectively simulate long-term mandibular arch retraction and occlusal plane rotation for the correction of a skeletal Class III malocclusion. Seventeen published case reports were selected of patients treated with statically determinate mechanics using posterior mandible or infrazygomatic crest bone screw anchorage to retract the mandibular arch. Two-dimensional measurements were made for incisor and molar movements, mandibular arch rotation, and retraction relative to the maxillary arch. A patient with cone-beam computed tomography imaging was selected for a retrospective FEA. The mean age for the sample was 23.3 ± 3.3 years; there were 7 men and 10 women. Mean incisor movements were 3.35 ± 1.55 mm of retraction and 2.18 ± 2.51 mm of extrusion. Corresponding molar movements were retractions of 4.85 ± 1.78 mm and intrusions of 0.85 ± 2.22 mm. Retraction of the mandibular arch relative to the maxillary arch was 4.88 ± 1.41 mm. Mean posterior rotation of the mandibular arch was -5.76° ± 4.77° (counterclockwise). The mean treatment time (n = 16) was 36.2 ± 15.3 months. Bone screws in the posterior mandibular region were more efficient for intruding molars and decreasing the vertical dimension of the occlusion to close an open bite. The full-cusp, skeletal Class III patient selected for FEA was treated to an American Board of Orthodontics Cast-Radiograph Evaluation score of 24 points in about 36 months by en-masse retraction and posterior rotation of the mandibular arch: the bilateral load on the mandibular segment was about 200 cN. The mandibular arch was retracted by about 5 mm, posterior rotation was about 16.5°, and molar intrusion was about 3

Influence of Axial Movement on Fatigue of Profile® Ni-Ti Rotary Instruments: an in vitro evaluation

Directory of Open Access Journals (Sweden)

Marie-Chantal Avoaka

2010-05-01

Full Text Available The aim of this study was to evaluate the influence of the axial movement and the angle of curve (in degrees on fatigue of nickel-titanium (Ni-Ti ProFile’ rotary endodontic instruments.Ni-Ti ProFile’ rotary instruments (Maillefer SA, Ballaigues, Switzerland, 25 mm long in the range of ISO size 15 to 40 with two tapers (0.4 and 0.6 were evaluated. They are divided in two groups: the instruments with axial movement and those without axial movement. The system used to test the fatigue is maintained in mechanical conditions as close as possible to the clinical situation. The axial movement is in the order of 2mm in corono-apical direction with a frequency of 1Hz. The concave radii incorporating a notched V-form for guiding the instruments were: 5; 7,5 and 10 mm. The rotary system is mounted on an electric handpiece and rotated at 350 rpm speed as recommended by the manufacturers. The instruments are rotated until their separation, and the time, in seconds, is recorded. Statístícal evaluation is undertaken using a two-way t-test to identify significant differences between variables in the study (p <0,05.We found significant statistical difference (p<0,05 between Ni-Ti engine drive ProFile’ instruments incorporating an axial movement and the instruments without axial movement with the same radius of curvature, size and taper.The incorporation of the axial movement increases significantly the life-span of the ProFile’ rotary instruments. This should reduce the risk of the instrument separation during the endodontic treatment

Modelling group dynamic animal movement

DEFF Research Database (Denmark)

Langrock, Roland; Hopcraft, J. Grant C.; Blackwell, Paul G.

2014-01-01

makes its movement decisions relative to the group centroid. The basic idea is framed within the flexible class of hidden Markov models, extending previous work on modelling animal movement by means of multi-state random walks. While in simulation experiments parameter estimators exhibit some bias......, to date, practical statistical methods which can include group dynamics in animal movement models have been lacking. We consider a flexible modelling framework that distinguishes a group-level model, describing the movement of the group's centre, and an individual-level model, such that each individual......Group dynamic movement is a fundamental aspect of many species' movements. The need to adequately model individuals' interactions with other group members has been recognised, particularly in order to differentiate the role of social forces in individual movement from environmental factors. However...

PELVIC ROTATION AND LOWER EXTREMITY MOTION WITH TWO DIFFERENT FRONT FOOT DIRECTIONS IN THE TENNIS BACKHAND GROUNDSTROKE

Directory of Open Access Journals (Sweden)

Sayumi Iwamoto

2013-06-01

Full Text Available When a tennis player steps forward to hit a backhand groundstroke in closed stance, modifying the direction of the front foot relative to the net may reduce the risk of ankle injury and increase performance. This study evaluated the relationship between pelvic rotation and lower extremity movement during the backhand groundstroke when players stepped with toes parallel to the net (Level or with toes pointed towards the net (Net. High school competitive tennis players (eleven males and seven females, 16.8 ± 0.8 years, all right- handed performed tennis court tests comprising five maximum speed directional runs to the court intersection line to hit an imaginary ball with forehand or backhand swings. The final backhand groundstroke for each player at the backcourt baseline was analyzed. Pelvic rotation and lower extremity motion were quantified using 3D video analysis from frontal and sagittal plane camera views reconstructed to 3D using DLT methods. Plantar flexion of ankle and supination of the front foot were displayed for both Net and Level groups during the late phase of the front foot step. The timings of the peak pelvis rotational velocity and peak pelvis rotational acceleration showed different pattern for Net and Level groups. The peak timing of the pelvis rotational velocity of the Level group occurred during the late phase of the step, suggesting an increase in the risk of inversion ankle sprain and a decrease in stroke power compared to the Net group

Single-leg squats can predict leg alignment in dancers performing ballet movements in "turnout".

Science.gov (United States)

Hopper, Luke S; Sato, Nahoko; Weidemann, Andries L

2016-01-01

The physical assessments used in dance injury surveillance programs are often adapted from the sports and exercise domain. Bespoke physical assessments may be required for dance, particularly when ballet movements involve "turning out" or external rotation of the legs beyond that typically used in sports. This study evaluated the ability of the traditional single-leg squat to predict the leg alignment of dancers performing ballet movements with turnout. Three-dimensional kinematic data of dancers performing the single-leg squat and five ballet movements were recorded and analyzed. Reduction of the three-dimensional data into a one-dimensional variable incorporating the ankle, knee, and hip joint center positions provided the strongest predictive model between the single-leg squat and the ballet movements. The single-leg squat can predict leg alignment in dancers performing ballet movements, even in "turned out" postures. Clinicians should pay careful attention to observational positioning and rating criteria when assessing dancers performing the single-leg squat.

Low relative error in consumer-grade GPS units make them ideal for measuring small-scale animal movement patterns

Directory of Open Access Journals (Sweden)

Greg A. Breed

2015-08-01

Full Text Available Consumer-grade GPS units are a staple of modern field ecology, but the relatively large error radii reported by manufacturers (up to 10 m ostensibly precludes their utility in measuring fine-scale movement of small animals such as insects. Here we demonstrate that for data collected at fine spatio-temporal scales, these devices can produce exceptionally accurate data on step-length and movement patterns of small animals. With an understanding of the properties of GPS error and how it arises, it is possible, using a simple field protocol, to use consumer grade GPS units to collect step-length data for the movement of small animals that introduces a median error as small as 11 cm. These small error rates were measured in controlled observations of real butterfly movement. Similar conclusions were reached using a ground-truth test track prepared with a field tape and compass and subsequently measured 20 times using the same methodology as the butterfly tracking. Median error in the ground-truth track was slightly higher than the field data, mostly between 20 and 30 cm, but even for the smallest ground-truth step (70 cm, this is still a signal-to-noise ratio of 3:1, and for steps of 3 m or more, the ratio is greater than 10:1. Such small errors relative to the movements being measured make these inexpensive units useful for measuring insect and other small animal movements on small to intermediate scales with budgets orders of magnitude lower than survey-grade units used in past studies. As an additional advantage, these units are simpler to operate, and insect or other small animal trackways can be collected more quickly than either survey-grade units or more traditional ruler/gird approaches.

Galvanic vestibular stimulation combines with Earth-horizontal rotation in roll to induce the illusion of translation.

Science.gov (United States)

Schneider, Erich; Bartl, Klaus; Glasauer, Stefan

2009-05-01

Human head rotation in roll around an earth-horizontal axis constitutes a vestibular stimulus that, by its rotational component, acts on the semicircular canals (SCC) and that, by its tilt of the gravity vector, also acts on the otoliths. Galvanic vestibular stimulation (GVS) is thought to resemble mainly a rotation in roll. A superposition of sinusoidal GVS with a natural earth-horizontal roll movement was therefore applied in order to cancel the rotation effects and to isolate the otolith activation. By self-adjusting the amplitude and phase of GVS, subjects were able to minimize their sensation of rotation and to generate the perception of a linear translation. The final adjustments are in the range of a model that predicts SCC activation during natural rotations and GVS. This indicates that the tilt-translation ambiguity of the otoliths is resolved by SCC-otolith interaction. It is concluded that GVS might be able to cancel rotations in roll and that the residual tilt of the gravitoinertial force is possibly interpreted as a linear translation.

Dynamics of human movement

NARCIS (Netherlands)

Koopman, Hubertus F.J.M.

2010-01-01

The part of (bio)mechanics that studies the interaction of forces on the human skeletal system and its effect on the resulting movement is called rigid body dynamics. Some basic concepts are presented: A mathematical formulation to describe human movement and how this relates on the mechanical loads

Deriving movement properties and the effect of the environment from the Brownian bridge movement model in monkeys and birds.

Science.gov (United States)

Buchin, Kevin; Sijben, Stef; van Loon, E Emiel; Sapir, Nir; Mercier, Stéphanie; Marie Arseneau, T Jean; Willems, Erik P

2015-01-01

The Brownian bridge movement model (BBMM) provides a biologically sound approximation of the movement path of an animal based on discrete location data, and is a powerful method to quantify utilization distributions. Computing the utilization distribution based on the BBMM while calculating movement parameters directly from the location data, may result in inconsistent and misleading results. We show how the BBMM can be extended to also calculate derived movement parameters. Furthermore we demonstrate how to integrate environmental context into a BBMM-based analysis. We develop a computational framework to analyze animal movement based on the BBMM. In particular, we demonstrate how a derived movement parameter (relative speed) and its spatial distribution can be calculated in the BBMM. We show how to integrate our framework with the conceptual framework of the movement ecology paradigm in two related but acutely different ways, focusing on the influence that the environment has on animal movement. First, we demonstrate an a posteriori approach, in which the spatial distribution of average relative movement speed as obtained from a "contextually naïve" model is related to the local vegetation structure within the monthly ranging area of a group of wild vervet monkeys. Without a model like the BBMM it would not be possible to estimate such a spatial distribution of a parameter in a sound way. Second, we introduce an a priori approach in which atmospheric information is used to calculate a crucial parameter of the BBMM to investigate flight properties of migrating bee-eaters. This analysis shows significant differences in the characteristics of flight modes, which would have not been detected without using the BBMM. Our algorithm is the first of its kind to allow BBMM-based computation of movement parameters beyond the utilization distribution, and we present two case studies that demonstrate two fundamentally different ways in which our algorithm can be applied to

A cross-sectional survey assessing sources of movement-related fear among people with fibromyalgia syndrome.

Science.gov (United States)

Russek, Leslie; Gardner, Sarah; Maguire, Kelly; Stevens, Caitlin; Brown, Erica Z; Jayawardana, Veroni; Mondal, Sumona

2015-06-01

Fear of movement may contribute to functional limitations and loss of well-being among individuals with fibromyalgia (FM). The objectives of this study were to assess factors contributing to movement-related fear and to explore relationships among these factors, function and wellness, in a widespread population of people with FM. This was an internet survey of individuals with FM. Respondents completed a battery of surveys including the Fibromyalgia Impact Questionnaire--Revised (FIQR), Tampa Scale of Kinesiophobia (TSK), Activities-Specific Balance Confidence Scale (ABC), Primary Care Posttraumatic Stress Disorder screen (PC-PTSD), Vertigo Symptom Scale (VSS-SF), a joint hypermobility syndrome screen (JHS), and screening questions related to obsessive-compulsive personality disorder (OCPD), physical activity, work status, and demographics. Analysis included descriptive statistics, Pearson product-moment correlations, and linear regression. Over a 2-year period, 1,125 people (97.6 % female) completed the survey battery. Kinesiophobia was present in 72.9 % of the respondents, balance confidence was compromised in 74.8 %, PTSD likely in 60.4 %, joint hypermobility syndrome likely in 46.6 %, and OCPD tendencies in 26.8 %. The total FIQR and FIQR perceived function subscores were highly correlated (p  0.4) with pain, kinesiophobia, balance confidence, and vertigo. Reported activity level had poor correlation (r < 0.25) with all measured variables. Pain, ABC, VSS, and TSK predicted FIQR and FIQR-pf, explaining 65 and 48 % of the variance, respectively. Kinesiophobia, balance complaints, vertigo, PTSD, and joint hypermobility were common in this population of people with FM. Sources of movement-related fear correlated to overall wellness and perceived function as measured by the FIQR and FIQR-pf.

Influence of implant number on the movement of mandibular implant overdentures.

Science.gov (United States)

Oda, Ken; Kanazawa, Manabu; Takeshita, Shin; Minakuchi, Shunsuke

2017-03-01

The rotational movement of an implant overdenture (IOD) has a negative effect on the perceived masticatory ability of the denture wearer. However, the influence of implant number on the movement of IODs has not been investigated. The purpose of this in vitro study was to evaluate the denture movement of mandibular IODs anchored by different numbers of implants. An edentulous mandibular test model with artificial mucosa and 5 experimental overdentures (N=5) was fabricated. The locator attachment system with blue nylon inserts was chosen for this study. Three implant positions were prepared: anterior midline (1-IOD), bilateral lateral incisor regions (2-IOD), and anterior midline and bilateral canine regions (3-IOD). Vertical loads of 50 N were applied to the mid-anterior region, the left canine region, the left premolar region, and the left first molar region. The vertical and horizontal displacements at the right distal edge and the vertical displacements at the loading point were measured. The displacement values were statistically analyzed using a 1-way analysis of variance and the post hoc Tukey honest significant difference test with the implant number as a factor. In addition, the values of the vertical and horizontal displacements at the distal edge of the overdenture were statistically compared using a paired t test, and the values of the vertical displacement at the distal edge of the overdenture were statistically analyzed by a repeated measures analysis of variance and the post hoc Tukey honest significance difference test with the loading point as a factor (a=.05). Upon anterior loading, the 2-IOD showed significantly larger vertical displacements at the right distal edge than the 1-IOD or 3-IOD (P.05). Within the limitations of this in vitro study, the following conclusions were drawn: During mastication with the anterior teeth, the use of 2 implants for anchoring an IOD increased the rotation of the denture base more than the use of 1 or 3 implants

M-dwarf rapid rotators and the detection of relatively young multiple M-star systems

International Nuclear Information System (INIS)

Rappaport, S.; Joss, M.; Sanchis-Ojeda, R.

2014-01-01

We have searched the Kepler light curves of ∼3900 M-star targets for evidence of periodicities that indicate, by means of the effects of starspots, rapid stellar rotation. Several analysis techniques, including Fourier transforms, inspection of folded light curves, 'sonograms', and phase tracking of individual modulation cycles, were applied in order to distinguish the periodicities due to rapid rotation from those due to stellar pulsations, eclipsing binaries, or transiting planets. We find 178 Kepler M-star targets with rotation periods, P rot , of <2 days, and 110 with P rot < 1 day. Some 30 of the 178 systems exhibit two or more independent short periods within the same Kepler photometric aperture, while several have 3 or more short periods. Adaptive optics imaging and modeling of the Kepler pixel response function for a subset of our sample support the conclusion that the targets with multiple periods are highly likely to be relatively young physical binary, triple, and even quadruple M star systems. We explore in detail the one object with four incommensurate periods all less than 1.2 days, and show that two of the periods arise from one of a close pair of stars, while the other two arise from the second star, which itself is probably a visual binary. If most of these M-star systems with multiple periods turn out to be bound M stars, this could prove a valuable way discovering young hierarchical M-star systems; the same approach may also be applicable to G and K stars. The ∼5% occurrence rate of rapid rotation among the ∼3900 M star targets is consistent with spin evolution models that include an initial contraction phase followed by magnetic braking, wherein a typical M star can spend several hundred Myr before spinning down to periods longer than 2 days.

The need for rotational margins in intensity-modulated radiotherapy and a new method for planning target volume design

International Nuclear Information System (INIS)

Langer, Mark Peter; Papiez, Lech; Spirydovich, Siarhei; Thai, Van

2005-01-01

Purpose: The effect of rotational errors on the coverage of clinical target volumes (CTVs) is examined. A new planning target volume (PTV) construction that considers the individual paths traced by movements of the target boundary points is developed. Methods and Materials: A standard uniform margin expansion was compared with a PTV constructed from the space swept out by a concave moving target. A new method formed the PTV by aggregating the separate convex hulls taken of the positions of the individual target boundary points in a sampling of CTV displacements. Results: A 0.5-cm uniform margin adequate for translations was inadequate given CTV rotation about a fixed off-center axis. A PTV formed of the target's swept-out area was 22% smaller than needed for coverage by a uniform margin, but computationally is not readily extended to translations combined with rotations about a shifting axis. Forming instead the union of convex hulls of the boundary points in a sampling of CTV displacements represented these movements in the PTV design and retained the target's concave shape. Conclusions: Planning target volumes should accommodate target rotation. The union of convex hulls of the boundary point positions in a sampling of displacements can effectively represent multiple sources of deviations while preserving target concavities

Movement disorders

International Nuclear Information System (INIS)

Leenders, K.L.

1986-01-01

This thesis describes the measurement of brain-tissue functions in patients with movement disorders using positron emission tomography (PET). This scanning technique is a method for direct in vivo quantitation of the regional tissue content of positron emitting radionuclides in brain (or other organs) in an essentially non-invasive way. Ch. 2 outlines some general features of PET and describes the scanner which has been used for the studies in this thesis. Also the tracer methodology, as applied to data investigations of movement disorders, are discussed. Ch. 3 contains the results of the PET investigations which were performed in the study of movement disorders. The results are presented in the form of 12 papers. The main goals of these studies were the understanding of the pathophysiology of Parkinson's disease, Huntington's chorea, Steele-Richardson-Olzewski syndrome and special case reports. Ch. 4 summarizes the results of these publications and Ch. 5 concludes the main part of this thesis with a general discussion of movement disorders in relation to PET investigations. 697 refs.; 60 figs.; 31 tabs

Relaxation processes in rotational motion

International Nuclear Information System (INIS)

Broglia, R.A.

1986-01-01

At few MeV above the yrast line the normally strong correlations among γ-ray energies in a rotational sequence become weaker. This observation can be interpreted as evidence for the damping of rotational motion in hot nuclei. It seems possible to relate the spreading width of the E2-rotational decay strength to the spread in frequency Δω 0 of rotational bands. The origin of these fluctuations is found in: (1) fluctuations in the occupation of special single-particle orbits which contribute a significant part of the total angular momentum; and (2) fluctuations in the moment of inertia induced by vibrations of the nuclear shape. Estimates of Δω 0 done making use of the hundred-odd known discrete rotational bands in the rare-earth region lead, for moderate spin and excitation energies (I ≅ 30 and U ≅ 3 to 4 MeV), to rotational spreading widths of the order of 60 to 160 keV in overall agreement with the data. 24 refs

49 CFR 236.776 - Movement, trailing.

Science.gov (United States)

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Movement, trailing. 236.776 Section 236.776 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Movement, trailing. The movement of a train over the points of a switch which face in the direction in...

49 CFR 236.774 - Movement, facing.

Science.gov (United States)

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Movement, facing. 236.774 Section 236.774 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Movement, facing. The movement of a train over the points of a switch which face in a direction opposite to...

Clinical features of movement disorders.

Science.gov (United States)

Yung, C Y

1983-08-01

The descriptive aspects of all types of movement disorders and their related syndromes and terminologies used in the literature are reviewed and described. This comprises the features of (a) movement disorders secondary to neurological diseases affecting the extrapyramidal motor system, such as: athetosis, chorea, dystonia, hemiballismus, myoclonus, tremor, tics and spasm, (b) drug induced movement disorders, such as: akathisia, akinesia, hyperkinesia, dyskinesias, extrapyramidal syndrome, and tardive dyskinesia, and (c) abnormal movements in psychiatric disorders, such as: mannerism, stereotyped behaviour and psychomotor retardation. It is intended to bring about a more comprehensive overview of these movement disorders from a phenomenological perspective, so that clinicians can familiarize with these features for diagnosis. Some general statements are made in regard to some of the characteristics of movement disorders.

Rotating Wigner molecules and spin-related behaviors in quantum rings

International Nuclear Information System (INIS)

Yang Ning; Zhu Jialin; Dai Zhensheng

2008-01-01

The trial wavefunctions for few-electron quantum rings are presented to describe the spin-dependent rotating Wigner molecule states. The wavefunctions are constructed from the single-particle orbits which contain two variational parameters to describe the shape and size dependence of electron localization in the ring-like confinement. They can explicitly show the size dependence of single-particle orbital occupation to give an understanding of the spin rules of ground states without magnetic fields. They can also correctly describe the spin and angular momentum transitions in magnetic fields. By examining the von Neumann entropy, it is demonstrated that the wavefunctions can illustrate the entanglement between electrons in quantum rings, including the AB oscillations as well as the spin and size dependence of the entropy. Such trial wavefunctions will be useful in investigating spin-related quantum behaviors of a few electrons in quantum rings

Mass transfer behavior of rotating square cylinder electrochemical reactor in relation to wastewater treatment

International Nuclear Information System (INIS)

Abdel-Aziz, M.S.M.; El-Shazly, A.H.; Farag, H.A.; Sedahmed, G.H.

2011-01-01

Highlights: → The work explores a new electrochemical reactor by using square rotating cylinders. → The results show that it is superior to the traditional circular rotating cylinder. → A dimensionless design equation for the new reactor was correlated. → The oxalic acid removal by the new reactor was succeeded and found promising. → The energy consumption per kg oxalic acid removed by the unit was calculated. - Abstract: Rates of mass transfer at a rotating square cylinder were measured by an electrochemical technique which involved measuring the limiting current of the cathodic reduction of K 3 Fe(CN) 6 in a large excess of NaOH solution. Variables studied were: cylinder rotation speed, physical properties of the solution and cylinder equivalent diameter. The data for the condition 1577 0.33 Re 0.45 For a given set of conditions the rate of mass transfer at the square rotating cylinder was found to be higher than that at the traditional circular rotating cylinder by an amount ranging from 47% to 200% depending on Re. The use of the square rotating cylinder electrode in removing oxalic acid from wastewater by anodic oxidation on Pb/PbO anode was examined and found to be promising.

Rotation of small clusters in sheared metallic glasses

International Nuclear Information System (INIS)

Delogu, Francesco

2011-01-01

Graphical abstract: When a Cu 50 Ti 50 metallic glass is shear-deformed, the irreversible rearrangement of local structures allows the rigid body rotation of clusters. Highlights: → A shear-deformed Cu 50 Ti 50 metallic glass was studied by molecular dynamics. → Atomic displacements occur at irreversible rearrangements of local structures. → The dynamics of such events includes the rigid body rotation of clusters. → Relatively large clusters can undergo two or more complete rotations. - Abstract: Molecular dynamics methods were used to simulate the response of a Cu 50 Ti 50 metallic glass to shear deformation. Attention was focused on the atomic displacements taking place during the irreversible rearrangement of local atomic structures. It is shown that the apparently disordered dynamics of such events hides the rigid body rotation of small clusters. Cluster rotation was investigated by evaluating rotation angle, axis and lifetimes. This permitted to point out that relatively large clusters can undergo two or more complete rotations.

Differential rotation in magnetic stars

International Nuclear Information System (INIS)

Moss, D.

1981-01-01

The possibility that large-scale magnetic fields in stars are the product of a contemporary dynamo situated in the convective stellar core, rather than being a fossil from an earlier stage in the history of the star, is investigated. It is demonstrated that then the envelope will almost inevitably be in a state of differential rotation. Some simple models are constructed to illustrate the magnitude of the effects on the structure of the envelope and magnetic field. It is found that, for models which are relatively rapidly rotating, a modest differential rotation at the surface of the core may increase considerably the ratio of internal to surface field, but only give rise to a small surface differential rotation. (author)

Passive Stretch Versus Active Stretch on Intervertebral Movement in Non - Specific Neck Pain

International Nuclear Information System (INIS)

Abd El - Aziz, A.H.; Amin, D.I.; Moustafa, I.

2016-01-01

Neck pain is one of the most common and painful musculoskeletal conditions. Point prevalence ranges from 6% to 22% and up to 38% of the elderly population, while lifetime prevalence ranges from 14,2% to 71%. Up till now no randomized study showed the effect between controversy of active and passive stretch on intervertebral movement. The purpose: the current study was to investigate the effect of the passive and active stretch on intervertebral movement in non - specific neck pain. Material and methods: Forty five subjects from both sexes with age range between 18 and 30 years and assigned in three groups, group I (15) received active stretch, ultrasound and TENS. Group II (15) received passive stretch, ultrasound and TENS. Group III (15) received ultrasound and TENS. The radiological assessment was used to measure rotational and translational movement of intervertebral movement before and after treatment. Results: MANOVA test was used for radiological assessment before and after treatment there was significant increase in intervertebral movement in group I as p value =0.0001. Conclusion: active stretch had a effect in increasing the intervertebral movement compared to the passive stretch

FUNCTIONAL MOVEMENT SCREENING: THE USE OF FUNDAMENTAL MOVEMENTS AS AN ASSESSMENT OF FUNCTION ‐ PART 1

OpenAIRE

Cook, Gray; Burton, Lee; Hoogenboom, Barbara J.; Voight, Michael

2014-01-01

To prepare an athlete for the wide variety of activities needed to participate in or return to their sport, the analysis of fundamental movements should be incorporated into screening in order to determine who possesses, or lacks, the ability to perform certain essential movements. In a series of two articles, the background and rationale for the analysis of fundamental movement will be provided. The Functional Movement Screen (FMS™) will be described, and any evidence related to its use will...

Electrolocation of objects in fluids by means of active sensor movements based on discrete EEVs.

Science.gov (United States)

Wolf-Homeyer, Sabine; Engelmann, Jacob; Schneider, Axel

2016-08-17

Weakly electric fish use self-generated electric fields for communication and for active electrolocation. The sensor part of the biological system consists of a vast amount of electroreceptors which are distributed across the skin of the electric fish. Fish utilise changes of their position and body geometry to aid in the extraction of sensory information. Inspired by the biological model, this study looks for a fixed, minimal scanning strategy compiled of active receptor-system movements that allows unique identification of the positions of objects in the vicinity. The localisation method is based on the superposition of numerical extracted contour-rings of rotated and/or linearly shifted EEVs (Solberg et al 2008 Int. J. Rob. Res. 27 529-48), simulated by means of FEM. For the evaluation of a movement sequence, matrices of unique intersection points and respective contrast functions are introduced. The resultant optimal scanning strategy consists of a combination of a linear shift and a rotation of the original EEV.

Rotational discontinuities in anisotropic plasmas

International Nuclear Information System (INIS)

Omidi, N.

1992-01-01

The kinetic structure of rotational discontinuities (RDs) in anisotropic plasmas with T perpendicular /T parallel > 1 is investigated by using a one-dimensional electromagnetic hybrid code. To form the RD, a new approach is used where the plasma is injected from one boundary and reflected from the other, resulting in the generation of a traveling fast shock and an RD. Unlike the previously used methods, no a priori assumptions are made regarding the initial structure (i.e. width or sense of rotation) of the rotational discontinuity. The results show that across the RD both the magnetic field strength and direction, as well as the plasma density change. Given that such a change can also be associated with an intermediate shock, the Rankine-Hugoniot relations are used to confirm that the observed structures are indeed RDs. It is found that the thickness of RDs is a few ion inertial lengths and is independent of the rotation angle. Also, the preferred sense of rotation is in the electron sense; however, RDs with a rotation angle larger than 180 degree are found to be unstable, changing their rotation to a stable ion sense

Degeneration of rapid eye movement sleep circuitry underlies rapid eye movement sleep behavior disorder.

Science.gov (United States)

McKenna, Dillon; Peever, John

2017-05-01

During healthy rapid eye movement sleep, skeletal muscles are actively forced into a state of motor paralysis. However, in rapid eye movement sleep behavior disorder-a relatively common neurological disorder-this natural process is lost. A lack of motor paralysis (atonia) in rapid eye movement sleep behavior disorder allows individuals to actively move, which at times can be excessive and violent. At first glance this may sound harmless, but it is not because rapid eye movement sleep behavior disorder patients frequently injure themselves or the person they sleep with. It is hypothesized that the degeneration or dysfunction of the brain stem circuits that control rapid eye movement sleep paralysis is an underlying cause of rapid eye movement sleep behavior disorder. The link between brain stem degeneration and rapid eye movement sleep behavior disorder stems from the fact that rapid eye movement sleep behavior disorder precedes, in the majority (∼80%) of cases, the development of synucleinopathies such as Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy, which are known to initially cause degeneration in the caudal brain stem structures where rapid eye movement sleep circuits are located. Furthermore, basic science and clinical evidence demonstrate that lesions within the rapid eye movement sleep circuits can induce rapid eye movement sleep-specific motor deficits that are virtually identical to those observed in rapid eye movement sleep behavior disorder. This review examines the evidence that rapid eye movement sleep behavior disorder is caused by synucleinopathic neurodegeneration of the core brain stem circuits that control healthy rapid eye movement sleep and concludes that rapid eye movement sleep behavior disorder is not a separate clinical entity from synucleinopathies but, rather, it is the earliest symptom of these disorders. © 2017 International Parkinson and Movement Disorder Society. © 2017 International Parkinson and

Single-leg squats can predict leg alignment in dancers performing ballet movements in “turnout”

Science.gov (United States)

Hopper, Luke S; Sato, Nahoko; Weidemann, Andries L

2016-01-01

The physical assessments used in dance injury surveillance programs are often adapted from the sports and exercise domain. Bespoke physical assessments may be required for dance, particularly when ballet movements involve “turning out” or external rotation of the legs beyond that typically used in sports. This study evaluated the ability of the traditional single-leg squat to predict the leg alignment of dancers performing ballet movements with turnout. Three-dimensional kinematic data of dancers performing the single-leg squat and five ballet movements were recorded and analyzed. Reduction of the three-dimensional data into a one-dimensional variable incorporating the ankle, knee, and hip joint center positions provided the strongest predictive model between the single-leg squat and the ballet movements. The single-leg squat can predict leg alignment in dancers performing ballet movements, even in “turned out” postures. Clinicians should pay careful attention to observational positioning and rating criteria when assessing dancers performing the single-leg squat. PMID:27895518

Optimal Tempo for Groove: Its Relation to Directions of Body Movement and Japanese nori

Directory of Open Access Journals (Sweden)

Takahide Etani

2018-04-01

Full Text Available The tendency for groove-based music to induce body movements has been linked to multiple acoustical factors. However, it is unclear how or whether tempo affects groove, although tempo significantly affects other aspects of music perception. To address this issue, the present study investigated effects of tempo, specific rhythmic organizations of patterns, and syncopation on groove and the induction of the sensation of wanting to move. We focused on the directions of body movement in particular by taking into account nori, which is an indigenous Japanese musical term used not only synonymously with groove, but also as a spatial metaphor indicating vertical or horizontal movement directions. Thus, the present study explored how groove was felt and defined, as well as how musical factors induced the sensation of wanting to move in cross-cultural context. A listening experiment was conducted using drum breaks as stimuli. Stimuli consisted of various rhythm patterns at six tempi from 60 to 200 BPM. The main findings are that: (1 an optimal tempo for groove existed for drum breaks at around 100–120 BPM, (2 an optimal tempo existed for the sensation of wanting to move the body in specific directions (i.e., back-and-forth and side-to-side, (3 groove and nori shared a similar concept of wanting to move but differed on several points (i.e., association with sense of pulse and fast tempo. Overall, the present study suggests that there is an optimal tempo for body movement related to groove. This finding has implications for the use of music or rhythmic stimuli to induce smooth motion in rehabilitation, therapy, or dance.

Optimal Tempo for Groove: Its Relation to Directions of Body Movement and Japanese nori.

Science.gov (United States)

Etani, Takahide; Marui, Atsushi; Kawase, Satoshi; Keller, Peter E

2018-01-01

The tendency for groove-based music to induce body movements has been linked to multiple acoustical factors. However, it is unclear how or whether tempo affects groove, although tempo significantly affects other aspects of music perception. To address this issue, the present study investigated effects of tempo, specific rhythmic organizations of patterns, and syncopation on groove and the induction of the sensation of wanting to move. We focused on the directions of body movement in particular by taking into account nori , which is an indigenous Japanese musical term used not only synonymously with groove, but also as a spatial metaphor indicating vertical or horizontal movement directions. Thus, the present study explored how groove was felt and defined, as well as how musical factors induced the sensation of wanting to move in cross-cultural context. A listening experiment was conducted using drum breaks as stimuli. Stimuli consisted of various rhythm patterns at six tempi from 60 to 200 BPM. The main findings are that: (1) an optimal tempo for groove existed for drum breaks at around 100-120 BPM, (2) an optimal tempo existed for the sensation of wanting to move the body in specific directions (i.e., back-and-forth and side-to-side), (3) groove and nori shared a similar concept of wanting to move but differed on several points (i.e., association with sense of pulse and fast tempo). Overall, the present study suggests that there is an optimal tempo for body movement related to groove. This finding has implications for the use of music or rhythmic stimuli to induce smooth motion in rehabilitation, therapy, or dance.

Rotating neutron stars with exotic cores: masses, radii, stability

Energy Technology Data Exchange (ETDEWEB)

Haensel, P.; Bejger, M.; Fortin, M.; Zdunik, L. [Polish Academy of Sciences, N. Copernicus Astronomical Center, Warszawa (Poland)

2016-03-15

A set of theoretical mass-radius relations for rigidly rotating neutron stars with exotic cores, obtained in various theories of dense matter, is reviewed. Two basic observational constraints are used: the largest measured rotation frequency (716Hz) and the maximum measured mass (2M {sub CircleDot}). The present status of measuring the radii of neutron stars is described. The theory of rigidly rotating stars in general relativity is reviewed and limitations of the slow rotation approximation are pointed out. Mass-radius relations for rotating neutron stars with hyperon and quark cores are illustrated using several models. Problems related to the non-uniqueness of the crust-core matching are mentioned. Limits on rigid rotation resulting from the mass-shedding instability and the instability with respect to the axisymmetric perturbations are summarized. The problem of instabilities and of the back-bending phenomenon are discussed in detail. Metastability and instability of a neutron star core in the case of a first-order phase transition, both between pure phases, and into a mixed-phase state, are reviewed. The case of two disjoint families (branches) of rotating neutron stars is discussed and generic features of neutron-star families and of core-quakes triggered by the instabilities are considered. (orig.)

Independent component analysis of gait-related movement artifact recorded using EEG electrodes during treadmill walking.

Directory of Open Access Journals (Sweden)

Kristine Lynne Snyder

2015-12-01

Full Text Available There has been a recent surge in the use of electroencephalography (EEG as a tool for mobile brain imaging due to its portability and fine time resolution. When EEG is combined with independent component analysis (ICA and source localization techniques, it can model electrocortical activity as arising from temporally independent signals located in spatially distinct cortical areas. However, for mobile tasks, it is not clear how movement artifacts influence ICA and source localization. We devised a novel method to collect pure movement artifact data (devoid of any electrophysiological signals with a 256-channel EEG system. We first blocked true electrocortical activity using a silicone swim cap. Over the silicone layer, we placed a simulated scalp with electrical properties similar to real human scalp. We collected EEG movement artifact signals from ten healthy, young subjects wearing this setup as they walked on a treadmill at speeds from 0.4-1.6 m/s. We performed ICA and dipole fitting on the EEG movement artifact data to quantify how accurately these methods would identify the artifact signals as non-neural. ICA and dipole fitting accurately localized 99% of the independent components in non-neural locations or lacked dipolar characteristics. The remaining 1% of sources had locations within the brain volume and low residual variances, but had topographical maps, power spectra, time courses, and event related spectral perturbations typical of non-neural sources. Caution should be exercised when interpreting ICA for data that includes semi-periodic artifacts including artifact arising from human walking. Alternative methods are needed for the identification and separation of movement artifact in mobile EEG signals, especially methods that can be performed in real time. Separating true brain signals from motion artifact could clear the way for EEG brain computer interfaces for assistance during mobile activities, such as walking.

Compensatory eye movements in mice

NARCIS (Netherlands)

A.M. van Alphen (Arjan)

2002-01-01

textabstractThis thesis will address the generation of compensatory eye movements in naturally mutated or genetically modified mice. The reason for generating compensatory eye movements is solely related to the requirements for good vision. In a subject moving through its environment the projection

Vergence-mediated changes in the axis of eye rotation during the human vestibulo-ocular reflex can occur independent of eye position.

Science.gov (United States)

Migliaccio, Americo A; Cremer, Phillip D; Aw, Swee T; Halmagyi, G Michael; Curthoys, Ian S; Minor, Lloyd B; Todd, Michael J

2003-07-01

The aim of this study was to determine whether vergence-mediated changes in the axis of eye rotation in the human vestibulo-ocular reflex (VOR) would obey Listing's Law (normally associated with saccadic eye movements) independent of the initial eye position. We devised a paradigm for disassociating the saccadic velocity axis from eye position by presenting near and far targets that were centered with respect to one eye. We measured binocular 3-dimensional eye movements using search coils in ten normal subjects and 3-dimensional linear head acceleration using Optotrak in seven normal subjects. The stimuli consisted of passive, unpredictable, pitch head rotations with peak acceleration of approximately 2000 degrees /s(2 )and amplitude of approximately 20 degrees. During the pitch head rotation, each subject fixated straight ahead with one eye, whereas the other eye was adducted 4 degrees during far viewing (94 cm) and 25 degrees during near viewing (15 cm). Our data showed expected compensatory pitch rotations in both eyes, and a vergence-mediated horizontal rotation only in the adducting eye. In addition, during near viewing we observed torsional eye rotations not only in the adducting eye but also in the eye looking straight ahead. In the straight-ahead eye, the change in torsional eye velocity between near and far viewing, which began approximately 40 ms after the start of head rotation, was 10+/-6 degrees /s (mean +/- SD). This change in torsional eye velocity resulted in a 2.4+/-1.5 degrees axis tilt toward Listing's plane in that eye. In the adducting eye, the change in torsional eye velocity between near and far viewing was 16+/-6 degrees /s (mean +/- SD) and resulted in a 4.1+/-1.4 degrees axis tilt. The torsional eye velocities were conjugate and both eyes partially obeyed Listing's Law. The axis of eye rotation tilted in the direction of the line of sight by approximately one-third of the angle between the line of sight and a line orthogonal to Listing

30 CFR 250.602 - Equipment movement.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Equipment movement. 250.602 Section 250.602... OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Well-Workover Operations § 250.602 Equipment movement. The movement of well-workover rigs and related equipment on and off a platform or from well to well on...

30 CFR 250.502 - Equipment movement.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Equipment movement. 250.502 Section 250.502... OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Well-Completion Operations § 250.502 Equipment movement. The movement of well-completion rigs and related equipment on and off a platform or from well to well...

The effect of rotations on Michelson interferometers

Energy Technology Data Exchange (ETDEWEB)

Maraner, Paolo, E-mail: pmaraner@unibz.it

2014-11-15

In the contest of the special theory of relativity, it is shown that uniform rotations induce a phase shift in Michelson interferometers. The effect is second order in the ratio of the interferometer’s speed to the speed of light, further suppressed by the ratio of the interferometer’s arms length to the radius of rotation and depends on the interferometer’s position in the co-rotating frame. The magnitude of the phase shift is just beyond the sensitivity of turntable rotated optical resonators used in present tests of Lorentz invariance. It grows significantly large in Earth’s rotated kilometer-scale Fabry–Perot enhanced interferometric gravitational-wave detectors where it appears as a constant bias. The effect can provide the means of sensing center and radius of rotations. - Highlights: • Rotations induce a phase shift in Michelson interferometers. • Earth’s rotation induces a constant bias in Michelson interferometers. • Michelson interferometers can be used to sense center and radius of rotations.

The effect of rotations on Michelson interferometers

International Nuclear Information System (INIS)

Maraner, Paolo

2014-01-01

In the contest of the special theory of relativity, it is shown that uniform rotations induce a phase shift in Michelson interferometers. The effect is second order in the ratio of the interferometer’s speed to the speed of light, further suppressed by the ratio of the interferometer’s arms length to the radius of rotation and depends on the interferometer’s position in the co-rotating frame. The magnitude of the phase shift is just beyond the sensitivity of turntable rotated optical resonators used in present tests of Lorentz invariance. It grows significantly large in Earth’s rotated kilometer-scale Fabry–Perot enhanced interferometric gravitational-wave detectors where it appears as a constant bias. The effect can provide the means of sensing center and radius of rotations. - Highlights: • Rotations induce a phase shift in Michelson interferometers. • Earth’s rotation induces a constant bias in Michelson interferometers. • Michelson interferometers can be used to sense center and radius of rotations

Breakdown of I-Love-Q Universality in Rapidly Rotating Relativistic Stars

Science.gov (United States)

Doneva, Daniela D.; Yazadjiev, Stoytcho S.; Stergioulas, Nikolaos; Kokkotas, Kostas D.

2014-01-01

It was shown recently that normalized relations between the moment of inertia (I), the quadrupole moment (Q), and the tidal deformability (Love number) exist and for slowly rotating neutron stars they are almost independent of the equation of state (EOS). We extend the computation of the I-Q relation to models rotating up to the mass-shedding limit and show that the universality of the relations is lost. With increasing rotation rate, the normalized I-Q relation departs significantly from its slow-rotation limit, deviating up to 40% for neutron stars and up to 75% for strange stars. The deviation is also EOS dependent and for a broad set of hadronic and strange matter EOSs the spread due to rotation is comparable to the spread due to the EOS, if one considers sequences with fixed rotational frequency. Still, for a restricted sample of modern realistic EOSs one can parameterize the deviations from universality as a function of rotation only. The previously proposed I-Love-Q relations should thus be used with care, because they lose their universality in astrophysical situations involving compact objects rotating faster than a few hundred Hz.

BREAKDOWN OF I-LOVE-Q UNIVERSALITY IN RAPIDLY ROTATING RELATIVISTIC STARS

International Nuclear Information System (INIS)

Doneva, Daniela D.; Yazadjiev, Stoytcho S.; Kokkotas, Kostas D.; Stergioulas, Nikolaos

2014-01-01

It was shown recently that normalized relations between the moment of inertia (I), the quadrupole moment (Q), and the tidal deformability (Love number) exist and for slowly rotating neutron stars they are almost independent of the equation of state (EOS). We extend the computation of the I-Q relation to models rotating up to the mass-shedding limit and show that the universality of the relations is lost. With increasing rotation rate, the normalized I-Q relation departs significantly from its slow-rotation limit, deviating up to 40% for neutron stars and up to 75% for strange stars. The deviation is also EOS dependent and for a broad set of hadronic and strange matter EOSs the spread due to rotation is comparable to the spread due to the EOS, if one considers sequences with fixed rotational frequency. Still, for a restricted sample of modern realistic EOSs one can parameterize the deviations from universality as a function of rotation only. The previously proposed I-Love-Q relations should thus be used with care, because they lose their universality in astrophysical situations involving compact objects rotating faster than a few hundred Hz

Vestibulo-ocular reflex of the squirrel monkey during eccentric rotation with centripetal acceleration along the naso-occipital axis

Science.gov (United States)

Merfeld, D. M.; Paloski, W. H. (Principal Investigator)

1996-01-01

The vestibulo-ocular reflexes (VOR) are determined not only by angular acceleration, but also by the presence of gravity and linear acceleration. This phenomenon was studied by measuring three-dimensional nystagmic eye movements, with implanted search coils, in four male squirrel monkeys. Monkeys were rotated in the dark at 200 degrees/s, centrally or 79 cm off-axis, with the axis of rotation always aligned with gravity and the spinal axis of the upright monkeys. The monkey's position relative to the centripetal acceleration (facing center or back to center) had a dramatic influence on the VOR. These studies show that a torsional response was always elicited that acted to shift the axis of eye rotation toward alignment with gravito-inertial force. On the other hand, a slow phase downward vertical response usually existed, which shifted the axis of eye rotation away from the gravito-inertial force. These findings were consistent across all monkeys. In another set of tests, the same monkeys were rapidly tilted about their interaural (pitch) axis. Tilt orientations of 45 degrees and 90 degrees were maintained for 1 min. Other than a compensatory angular VOR during the rotation, no consistent eye velocity response was ever observed during or following the tilt. The absence of any response following tilt proves that the observed torsional and vertical responses were not a positional nystagmus. Model simulations qualitatively predict all components of these eccentric rotation and tilt responses. These simulations support the conclusion that the VOR during eccentric rotation may consist of two components: a linear VOR and a rotational VOR. The model predicts a slow phase downward, vertical, linear VOR during eccentric rotation even though there was never a change in the force aligned with monkey's spinal (Z) axis. The model also predicts the torsional components of the response that shift the rotation axis of the angular VOR toward alignment with gravito-inertial force.

On the stability of rotational discontinuities

International Nuclear Information System (INIS)

Richter, P.; Scholer, M.

1989-01-01

The stability of symmetric rotational discontinuities in which the magnetic field rotates by 180 degree is investigated by means of a one-dimensional self-consistent hybrid code. Rotational discontinuities with an angle Θ > 45 degree between the discontinuity normal direction and the upstream magnetic field are found to be relatively stable. The discontinuity normal is in the x direction and the initial magnetic field has finite y component only in the transition region. In the case of the ion (left-handed) sense of rotation of the tangential magnetic field, the transition region does not broaden with time. In the case of the electron (right-handed) sense of rotation, a damped wavetrain builds up in the B y component downstream of the rotational discontinuity and the discontinuity broadens with time. Rotational discontinuities with smaller angles, Θ, are unstable. Examples for a rotational discontinuity with Θ = 30 degree and the electron sense of rotation as well as a rotational discontinuity with Θ = 15 degree and the ion sense of rotation show that these discontinuities into waves. These waves travel approximately with Alfven velocity in the upstream direction and are therefore phase standing in the simulation system. The magnetic hodograms of these disintegrated discontinuities are S-shaped. The upstream portion of the hodogram is always right-handed; the downstream portion is always left-handed

Can shoulder range of movement be measured accurately using the Microsoft Kinect sensor plus Medical Interactive Recovery Assistant (MIRA) software?

Science.gov (United States)

Wilson, James D; Khan-Perez, Jennifer; Marley, Dominic; Buttress, Susan; Walton, Michael; Li, Baihua; Roy, Bibhas

2017-12-01

This study compared the accuracy of measuring shoulder range of movement (ROM) with a simple laptop-sensor combination vs. trained observers (shoulder physiotherapists and shoulder surgeons) using motion capture (MoCap) laboratory equipment as the gold standard. The Microsoft Kinect sensor (Microsoft Corp., Redmond, WA, USA) tracks 3-dimensional human motion. Ordinarily used with an Xbox (Microsoft Corp.) video game console, Medical Interactive Recovery Assistant (MIRA) software (MIRA Rehab Ltd., London, UK) allows this small sensor to measure shoulder movement with a standard computer. Shoulder movements of 49 healthy volunteers were simultaneously measured by trained observers, MoCap, and the MIRA device. Internal rotation was assessed with the shoulder abducted 90° and external rotation with the shoulder adducted. Visual estimation and MIRA measurements were compared with gold standard MoCap measurements for agreement using Bland-Altman methods. There were 1670 measurements analyzed. The MIRA evaluations of all 4 cardinal shoulder movements were significantly more precise, with narrower limits of agreement, than the measurements of trained observers. MIRA achieved ±11° (95% confidence interval [CI], 8.7°-12.6°) for forward flexion vs. ±16° (95% CI, 14.6°-17.6°) by trained observers. For abduction, MIRA showed ±11° (95% CI, 8.7°-12.8°) against ±15° (95% CI, 13.4°-16.2°) for trained observers. MIRA attained ±10° (95% CI, 8.1°-11.9°) during external rotation measurement, whereas trained observers only reached ±21° (95% CI, 18.7°-22.6°). For internal rotation, MIRA achieved ±9° (95% CI, 7.2°-10.4°), which was again better than TOs at ±18° (95% CI, 16.0°-19.3°). A laptop combined with a Microsoft Kinect sensor and the MIRA software can measure shoulder movements with acceptable levels of accuracy. This technology, which can be easily set up, may also allow precise shoulder ROM measurement outside the clinic setting. Copyright © 2017

Human movement is both diffusive and directed.

Directory of Open Access Journals (Sweden)

Mark Padgham

Full Text Available Understanding the influence of the built environment on human movement requires quantifying spatial structure in a general sense. Because of the difficulty of this task, studies of movement dynamics often ignore spatial heterogeneity and treat movement through journey lengths or distances alone. This study analyses public bicycle data from central London to reveal that, although journey distances, directions, and frequencies of occurrence are spatially variable, their relative spatial patterns remain largely constant, suggesting the influence of a fixed spatial template. A method is presented to describe this underlying space in terms of the relative orientation of movements toward, away from, and around locations of geographical or cultural significance. This produces two fields: one of convergence and one of divergence, which are able to accurately reconstruct the observed spatial variations in movement. These two fields also reveal categorical distinctions between shorter journeys merely serving diffusion away from significant locations, and longer journeys intentionally serving transport between spatially distinct centres of collective importance. Collective patterns of human movement are thus revealed to arise from a combination of both diffusive and directed movement, with aggregate statistics such as mean travel distances primarily determined by relative numbers of these two kinds of journeys.

Physiological modules for generating discrete and rhythmic movements: component analysis of EMG signals.

Science.gov (United States)

Bengoetxea, Ana; Leurs, Françoise; Hoellinger, Thomas; Cebolla, Ana Maria; Dan, Bernard; Cheron, Guy; McIntyre, Joseph

2014-01-01

A central question in Neuroscience is that of how the nervous system generates the spatiotemporal commands needed to realize complex gestures, such as handwriting. A key postulate is that the central nervous system (CNS) builds up complex movements from a set of simpler motor primitives or control modules. In this study we examined the control modules underlying the generation of muscle activations when performing different types of movement: discrete, point-to-point movements in eight different directions and continuous figure-eight movements in both the normal, upright orientation and rotated 90°. To test for the effects of biomechanical constraints, movements were performed in the frontal-parallel or sagittal planes, corresponding to two different nominal flexion/abduction postures of the shoulder. In all cases we measured limb kinematics and surface electromyographic activity (EMG) signals for seven different muscles acting around the shoulder. We first performed principal component analysis (PCA) of the EMG signals on a movement-by-movement basis. We found a surprisingly consistent pattern of muscle groupings across movement types and movement planes, although we could detect systematic differences between the PCs derived from movements performed in each shoulder posture and between the principal components associated with the different orientations of the figure. Unexpectedly we found no systematic differences between the figure eights and the point-to-point movements. The first three principal components could be associated with a general co-contraction of all seven muscles plus two patterns of reciprocal activation. From these results, we surmise that both "discrete-rhythmic movements" such as the figure eight, and discrete point-to-point movement may be constructed from three different fundamental modules, one regulating the impedance of the limb over the time span of the movement and two others operating to generate movement, one aligned with the

MaRGEE: Move and Rotate Google Earth Elements

Science.gov (United States)

Dordevic, Mladen M.; Whitmeyer, Steven J.

2015-12-01

Google Earth is recognized as a highly effective visualization tool for geospatial information. However, there remain serious limitations that have hindered its acceptance as a tool for research and education in the geosciences. One significant limitation is the inability to translate or rotate geometrical elements on the Google Earth virtual globe. Here we present a new JavaScript web application to "Move and Rotate Google Earth Elements" (MaRGEE). MaRGEE includes tools to simplify, translate, and rotate elements, add intermediate steps to a transposition, and batch process multiple transpositions. The transposition algorithm uses spherical geometry calculations, such as the haversine formula, to accurately reposition groups of points, paths, and polygons on the Google Earth globe without distortion. Due to the imminent deprecation of the Google Earth API and browser plugin, MaRGEE uses a Google Maps interface to facilitate and illustrate the transpositions. However, the inherent spatial distortions that result from the Google Maps Web Mercator projection are not apparent once the transposed elements are saved as a KML file and opened in Google Earth. Potential applications of the MaRGEE toolkit include tectonic reconstructions, the movements of glaciers or thrust sheets, and time-based animations of other large- and small-scale geologic processes.

Energy landscapes shape animal movement ecology.

Science.gov (United States)

Shepard, Emily L C; Wilson, Rory P; Rees, W Gareth; Grundy, Edward; Lambertucci, Sergio A; Vosper, Simon B

2013-09-01

The metabolic costs of animal movement have been studied extensively under laboratory conditions, although frequently these are a poor approximation of the costs of operating in the natural, heterogeneous environment. Construction of "energy landscapes," which relate animal locality to the cost of transport, can clarify whether, to what extent, and how movement properties are attributable to environmental heterogeneity. Although behavioral responses to aspects of the energy landscape are well documented in some fields (notably, the selection of tailwinds by aerial migrants) and scales (typically large), the principles of the energy landscape extend across habitat types and spatial scales. We provide a brief synthesis of the mechanisms by which environmentally driven changes in the cost of transport can modulate the behavioral ecology of animal movement in different media, develop example cost functions for movement in heterogeneous environments, present methods for visualizing these energy landscapes, and derive specific predictions of expected outcomes from individual- to population- and species-level processes. Animals modulate a suite of movement parameters (e.g., route, speed, timing of movement, and tortuosity) in relation to the energy landscape, with the nature of their response being related to the energy savings available. Overall, variation in movement costs influences the quality of habitat patches and causes nonrandom movement of individuals between them. This can provide spatial and/or temporal structure to a range of population- and species-level processes, ultimately including gene flow. Advances in animal-attached technology and geographic information systems are opening up new avenues for measuring and mapping energy landscapes that are likely to provide new insight into their influence in animal ecology.

Wave-driven Rotation in Supersonically Rotating Mirrors

Energy Technology Data Exchange (ETDEWEB)

A. Fetterman and N.J. Fisch

2010-02-15

Supersonic rotation in mirrors may be produced by radio frequency waves. The waves produce coupled diffusion in ion kinetic and potential energy. A population inversion along the diffusion path then produces rotation. Waves may be designed to exploit a natural kinetic energy source or may provide the rotation energy on their own. Centrifugal traps for fusion and isotope separation may benefit from this wave-driven rotation.

Wave-driven Rotation in Supersonically Rotating Mirrors

International Nuclear Information System (INIS)

Fetterman, A.; Fisch, N.J.

2010-01-01

Supersonic rotation in mirrors may be produced by radio frequency waves. The waves produce coupled diffusion in ion kinetic and potential energy. A population inversion along the diffusion path then produces rotation. Waves may be designed to exploit a natural kinetic energy source or may provide the rotation energy on their own. Centrifugal traps for fusion and isotope separation may benefit from this wave-driven rotation.

Boundary Layer Control of Rotating Convection Systems

Science.gov (United States)

King, E. M.; Stellmach, S.; Noir, J.; Hansen, U.; Aurnou, J. M.

2008-12-01

Rotating convection is ubiquitous in the natural universe, and is likely responsible for planetary processes such magnetic field generation. Rapidly rotating convection is typically organized by the Coriolis force into tall, thin, coherent convection columns which are aligned with the axis of rotation. This organizational effect of rotation is thought to be responsible for the strength and structure of magnetic fields generated by convecting planetary interiors. As thermal forcing is increased, the relative influence of rotation weakens, and fully three-dimensional convection can exist. It has long been assumed that rotational effects will dominate convection dynamics when the ratio of buoyancy to the Coriolis force, the convective Rossby number, Roc, is less than unity. We investigate the influence of rotation on turbulent Rayleigh-Benard convection via a suite of coupled laboratory and numerical experiments over a broad parameter range: Rayleigh number, 10310; Ekman number, 10-6≤ E ≤ ∞; and Prandtl number, 1≤ Pr ≤ 100. In particular, we measure heat transfer (as characterized by the Nusselt number, Nu) as a function of the Rayleigh number for several different Ekman and Prandtl numbers. Two distinct heat transfer scaling regimes are identified: non-rotating style heat transfer, Nu ~ Ra2/7, and quasigeostrophic style heat transfer, Nu~ Ra6/5. The transition between the non-rotating regime and the rotationally dominant regime is described as a function of the Ekman number, E. We show that the regime transition depends not on the global force balance Roc, but on the relative thicknesses of the thermal and Ekman boundary layers. The transition scaling provides a predictive criterion for the applicability of convection models to natural systems such as Earth's core.

Optimization of multi-slice helical respiration-correlated CT: the effects of table speed and rotation time

International Nuclear Information System (INIS)

Wink, Nicole M; McNitt-Gray, Michael F; Solberg, Timothy D

2005-01-01

While respiration-correlated CT is gaining acceptance in clinical radiotherapy, the effect of scanning parameters on the image quality has yet to be addressed. The intent of this study was to characterize the effects of gantry rotation and table speed on various image quality characteristics in multi-slice, helical, retrospectively-gated CT images. Images of stationary and moving phantoms were obtained in helical mode on a 20-slice CT scanner. Motion was generated by a computer-controlled platform capable of moving simultaneously in two dimensions. Motion was monitored using a pressure gauge inserted inside an adjustable belt. Selected scans were retrospectively gated into ten phases based on the monitored motion. Gantry rotation speeds of 0.5 s and 1.0 s were evaluated with pitches ranging from 0.1 to 0.45. Several parameters, including calculated object volumes, trajectory (movement from peak to trough), deformation (actual volume divided by volume created with the maximum diameter of contoured object) and z-axis resolution, were used to characterize image quality. These studies indicate that for objects in the peak phase of a movement pattern that simulates breathing, retrospectively gated scans using fast gantry rotation speeds produce volume, trajectory, deformation and z-axis resolution results comparable with those of a stationary object

Movement as utopia.

Science.gov (United States)

Couton, Philippe; López, José Julián

2009-10-01

Opposition to utopianism on ontological and political grounds has seemingly relegated it to a potentially dangerous form of antiquated idealism. This conclusion is based on a restrictive view of utopia as excessively ordered panoptic discursive constructions. This overlooks the fact that, from its inception, movement has been central to the utopian tradition. The power of utopianism indeed resides in its ability to instantiate the tension between movement and place that has marked social transformations in the modern era. This tension continues in contemporary discussions of movement-based social processes, particularly international migration and related identity formations, such as open borders transnationalism and cosmopolitanism. Understood as such, utopia remains an ongoing and powerful, albeit problematic instrument of social and political imagination.

Induction of poloidal rotation by mean of a ponderomotive force; Induccion de rotacion poloidal por medio de una fuerza ponderomotriz

Energy Technology Data Exchange (ETDEWEB)

Gutierrez T, C. [Instituto Nacional de Investigaciones Nucleares, Departamento de Fisica, Salazar, Estado de Mexico, C.P. 52045 (Mexico); Martinell, J. [Instituto de Ciencias Nucleares, UNAM, C.P. 04510, Mexico D.F. (Mexico)

1999-07-01

When a plasma is radiated with a radiofrequency wave (RF) with fluxes of energy at hundred megawatts order (MW) the effect the of ponderomotive force (PM) is very important. This force applied to the plasma column can generate a rotation movement by a non-resonant mechanism. Particularly, it is known that the poloidal rotation can be induced by direct action of the PM force poloidal moment. This poloidal rotation of the plasma column can to explain the appearance of high confinement regime (H) in Tokamaks. In this work, it is analysed this mechanism, showing that if it is operated efficiently with the poloidal and parallel components of PM force then could be intensified the poloidal rotation moreover it is showed the form in which the asymptotic value of this rotation is established. (Author)

Event-related mu-rhythm desynchronization during movement observation is impaired in Parkinson’s disease

NARCIS (Netherlands)

Heida, Tjitske; Poppe, N.R.; de Vos, Cecilia Cecilia Clementine; van Putten, Michel Johannes Antonius Maria; van Vugt, J.P.P.

2014-01-01

Objective: Patients with Parkinson’s disease often experience difficulties in adapting movements and learning alternative movements to compensate for symptoms. Since observation of movement has been demonstrated to lead to the formation of a lasting specific motor memory that resembled that elicited

A Finger Exoskeleton Robot for Finger Movement Rehabilitation

Directory of Open Access Journals (Sweden)

Tzu-Heng Hsu

2017-07-01

Full Text Available In this study, a finger exoskeleton robot has been designed and presented. The prototype device was designed to be worn on the dorsal side of the hand to assist in the movement and rehabilitation of the fingers. The finger exoskeleton is 3D-printed to be low-cost and has a transmission mechanism consisting of rigid serial links which is actuated by a stepper motor. The actuation of the robotic finger is by a sliding motion and mimics the movement of the human finger. To make it possible for the patient to use the rehabilitation device anywhere and anytime, an Arduino™ control board and a speech recognition board were used to allow voice control. As the robotic finger follows the patients voice commands the actual motion is analyzed by Tracker image analysis software. The finger exoskeleton is designed to flex and extend the fingers, and has a rotation range of motion (ROM of 44.2°.

Effect of Target Location on Dynamic Visual Acuity During Passive Horizontal Rotation