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Results 301 - 350 of 1469
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Lanatà Antonio - - 2010
The purpose of this study is to comparatively evaluate the performance of different wearable systems based on indirect breathing monitoring in terms of susceptibility to motion artifacts. These performances are compared with direct respiratory measurements using a spirometer, which is accurate, reliable, and less sensitive to movement artifacts, but cannot ...
Narazaki T - - 2009
Air-breathing marine animals, including sea turtles, utilise two fundamentally different environments (i.e. sea surface and underwater) during migration. Many satellite telemetry studies have shown travel paths at relatively large spatio-temporal scales, discussing the orientation and navigation mechanisms that guide turtles. However, as travel paths obtained by satellite telemetry only reflect ...
Plank Michael J - - 2009
A large number of empirical studies have attributed L?vy search patterns to the foraging movements of animals. Typically, this is done by fitting a power-law distribution with an exponent of 1 < mu < or = 3 to the observed step lengths. Most studies record the animal's location at equally ...
Amano Tatsuya - - 2009
Animal movements in heterogeneous environments play a crucial role in a variety of ecological processes. Although a hierarchical structure to the scale of movements has been observed in many animal species, few studies to date have revealed what causes such multi-spatial scale movements within the framework of optimal theories. Using ...
Tijtgat Pieter P Department of Movement and Sports Sciences, Faculty of Medicine and Health Sciences, Ghent University, Watersportlaan 2, 9000, Ghent, Belgium. - - 2010
The purpose of this experiment was to examine the effects of advance knowledge on the kinematics of one-handed catching. Balls were launched from a distance of 8.4 m by a ball-projection machine with adjustable launching speed. Fifteen skilled ball catchers caught 160 balls with their preferred hand under blocked-order (4 ...
Sing Gary C - - 2009
The motor commands required to control voluntary movements under various environmental conditions may be formed by adaptively combining a fixed set of motor primitives. Since this motor output must contend with state-dependent physical dynamics during movement, these primitives are thought to depend on the position and velocity of motion. Using ...
van der Wel Robrecht P R D - - 2009
Qualitative and quantitative changes characterize locomotion and rhythmic interlimb coordination at different speeds. Legs and hands do not move more or less quickly; they also adopt different relative coordination patterns. In the present article, the authors asked whether similar transitions occur for unimanual hand movements when speed is slowed below ...
Allen David P - - 2010
During dynamic voluntary movements, power in the alpha- and beta-bands resulting from synchronized neuronal activity is modulated in a manner that is time-locked to movement onset. These signals can be readily recorded from the scalp surface using electroencephalography. Abnormalities in the magnitude and timing of these oscillations are present in ...
Sülzenbrück Sandra S IfADo, Leibniz Research Centre for Working Environment and Human Factors, Ardeystrasse 67, 44139, Dortmund, Germany. - - 2010
We studied adaptation to the visuo-motor transformation of a virtual and a real two-sided sliding lever. In a previous study (Sülzenbrück and Heuer in Exp Brain Res 195:153-165, 2009) we had found essentially no differences. However, adaptation had been restricted to a simplified symmetry approximation of the transformation. In the ...
Wisbey Ben - - 2010
Global positioning system (GPS) monitoring of movement patterns is widespread in elite football including the Australian Football League (AFL). However documented analysis of this activity is lacking. We quantified the movement patterns of AFL football and differences between nomadic (midfield), forward and defender playing positions, and determined whether the physical ...
Amrhein Valentin - - 2010
1. In territorial contests, not only acoustic or other signals, but also the movements of a territorial intruder are likely to influence the response of a resident. 2. We tested this movement hypothesis by simulating moving vs. stationary intruders into the territories of winter wrens Troglodytes troglodytes, using the same ...
Page Alvaro - - 2010
This paper presents a model for determining the path of the instantaneous helical axis (IHA) that optimally represents human planar motions with one functional degree of freedom (fDOF). A human movement is said to have one fDOF when all degrees of freedom (DOFs) are coordinated such that all the kinematic ...
Jastorff Jan - - 2009
Recognition of actions and complex movements is fundamental for social interactions and action understanding. While the relationship between motor expertise and visual recognition of body movements has received a vast amount of interest, the role of visual learning remains largely unexplored. Combining psychophysics and functional magnetic resonance imaging (fMRI) experiments, ...
Volkov Alexander G - - 2010
Thigmonastic movements in the sensitive plant Mimosa pudica L., associated with fast responses to environmental stimuli, appear to be regulated through electrical and chemical signal transductions. The thigmonastic responses of M. pudica can be considered in three stages: stimulus perception, electrical signal transmission and induction of mechanical, hydrodynamical and biochemical ...
Hogan Neville - - 2009
Studies of sensory-motor performance, including those concerned with changes because of age, disease, or therapeutic intervention, often use measures based on jerk, the time derivative of acceleration, to quantify smoothness and coordination. However, results have been mixed: some researchers report sensitive discrimination of subtle differences, whereas others fail to find ...
Fiebig Lena - - 2009
Ongoing economic losses by and exposure of humans to highly pathogenic avian influenza (HPAI) in poultry flocks across Asia and parts of Africa and Europe motivate also outbreak-free countries such as Switzerland to invest in preparedness planning. Country-specific population data on between-farm contacts are required to anticipate probable patterns of ...
Buckingham Gavin G Department of Psychology, University of Western Ontario, London, ON, N6A-5C2, Canada. - - 2010
It is far more difficult to detect a small tactile stimulation on a finger that is moving compared to when it is static. This suppression of tactile information during motion, known as tactile gating, has been examined in some detail during single-joint movements. However, the existence and time course of ...
Duffield Rob - - 2010
The aim of this study was to assess the accuracy and reliability of global positioning system (GPS) measures of distance and speed, compared to a high-resolution motion analysis system, for confined movement patterns used in many court-based sports. A single male participant performed 10 repetitions of four respective drills replicating ...
Shimada Sotaro S Department of Electronics and Bioinformatics, School of Science and Technology, Meiji University, 1-1-1 Higashi-Mita, Tama-ku, Kawasaki, 214-8571, Japan. - - 2010
Temporal congruency between the efference copy of a motor command and the reafferent sensory feedback is crucial for identifying self-generated body movements. We investigated how temporal discrepancy between the efference copy and visual feedback affects the self-body movement recognition process. Subjects experienced active and passive hand movements under conditions of ...
Cressman Erin K - - 2009
Goal-directed reaches are rapidly adapted following exposure to misaligned visual feedback of the hand. It has been suggested that these changes in reaches result in sensory recalibration (i.e., realigning proprioceptive estimates of hand position to match the visual estimates). In the current study we tested whether visuomotor adaptation results in ...
Wild Kelly S KS Faculty of Life Sciences, University of Manchester, PO Box 88, Sackville St, Manchester, M60 1QD, UK. - - 2010
This study took a quantitative approach to investigate movement kinematics during the imitation of goal-directed and non-goal directed movements. Motion tracking equipment was used to record the hand movements of 15 healthy participants during an imitation task involving aiming movements that varied in speed. We predicted that movement kinematics would ...
Pitetti Kenneth H - - 2009
Pedometer accuracy for steps and activity time during dynamic movement for youth with intellectual disabilities (ID) were examined. Twenty-four youth with ID (13 girls, 13.1 +/- 3.2 yrs; 11 boys, 14.7 +/- 2.7 yrs) were videotaped during adapted physical education class while wearing a Walk4Life 2505 pedometer in five locations ...
Jackson Heather Bird - - 2009
The ability to disperse among patches is central to population dynamics in fragmented landscapes. Although saproxylic (=dead wood dependent) insects live in extremely fragmented forest ecosystems and comprise a significant proportion of the biodiversity therein, few studies have focused on dispersal of members in this group. We quantified the terrestrial ...
Boukari Hacène - - 2009
Time-resolved confocal microscopy and fluorescence correlation spectroscopy were used to examine the movements of fluorescently labeled HIV-virions (approximately 100 nm) added to samples of human cervical mucus. Particle-tracking analysis indicates that the motion of most virions is decreased 200-fold compared to that in aqueous solution and is not driven by ...
Pham Quang-Cuong - - 2009
We investigated the nature of the control mechanisms at work during goal-oriented locomotion. In particular, we tested the effects of vision, locomotor speed, and the presence of via points on the geometric and kinematic properties of locomotor trajectories. We first observed that the average trajectories recorded in visual and nonvisual ...
Higham Timothy E - - 2010
Many animals lose and regenerate appendages, and tail autotomy in lizards is an extremely well-studied example of this. Whereas the energetic, ecological and functional ramifications of tail loss for many lizards have been extensively documented, little is known about the behaviour and neuromuscular control of the autotomized tail. We used ...
Hajnal Alen - - 2009
The current study examined whether the amount and location of available movement information influenced the stability of visuomotor coordination. Participants coordinated a handheld pendulum with an oscillating visual stimulus in an inphase and antiphase manner. The effects of occluding different amounts of phase at different phase locations were examined. Occluding ...
David Fabian J FJ Department of Kinesiology and Nutrition, University of Illinois at Chicago, Chicago, USA. - - 2009
It has previously been found that in fast point-to-point arm movements, proprioceptive feedback is centrally suppressed at the beginning of movement and is facilitated at a time that is correlated with temporal parameters of the planned movement. Here, we show that this correlation holds when subjects are explicitly instructed to ...
Reichenbach Alexandra - - 2009
Goal-directed movements are executed under the permanent supervision of the central nervous system, which continuously processes sensory afferents and triggers on-line corrections if movement accuracy seems to be compromised. For arm reaching movements, visual information about the hand plays an important role in this supervision, notably improving reaching accuracy. Here, ...
Colombo Roberto - - 2010
The aim of this study was to describe in detail a new method, called normalized force control parameter (nFCP), to measure changes in movement dynamics obtained during robot-aided neurorehabilitation, and to evaluate its ability to estimate the clinical scales. The study was conducted in a group of 18 subjects after ...
Hajnal Alen A Department of Psychology, University of Southern Mississippi, 118 College Dr. #5025, Hattiesburg, MS, 39406, USA. - - 2009
The current study examined whether the amount and location of available movement information influenced the stability of visuo-motor coordination. Participants coordinated a hand-held pendulum with an oscillating visual stimulus in an inphase and antiphase manner. The effects of occluding different amounts of phase at different phase locations were examined. Occluding ...
Short Fay - - 2009
Hari and Jousmaki (1996) found that motor activity is initiated more efficiently in response to stimuli located on the responding limb as opposed to near the limb. Our research investigated the basis for this difference in spatial coding. We conducted 8 experiments using virtual reality to manipulate the visual feedback ...
Ashenfelter Kathleen T - - 2009
This study examined the influence of sex, social dominance, and context on motion-tracked head movements during dyadic conversations. Windowed cross-correlation analyses found high peak correlation between conversants' head movements over short ( approximately 2-s) intervals and a high degree of nonstationarity. Nonstationarity in head movements was found to be positively ...
Schweizer Andreas - - 2009
The aim of the study was to investigate the influence of a preceding flexion or extension movement on the static interaction of human finger flexor tendons and pulleys concerning flexion torque being generated. Six human fresh frozen cadaver long fingers were mounted in an isokinetic movement device for the proximal ...
Broderick Michael P MP Motor Control Laboratory, Department of Kinesiology, Arizona State University, P.O. Box 870404, Tempe, AZ, 85287-0404, USA. - - 2009
To address the hypothesis that Parkinson's disease (PD) patients have deficits in controlling acceleration, a drawing task was used in which target size, frequency, and weight of pen were manipulated. In accordance with previous results, it was found that, relative to controls, PD patients produced movements at the required frequency, ...
Stegemöller Elizabeth L - - 2009
In young healthy adults, syncopated finger movements (movements between consecutive beats) are characterized by a frequency-dependent change in phase at movement rates near 2 Hz. A similar frequency-dependent phase transition is observed during bimanual anti-phase (asymmetric) tasks in healthy young adults, but this transition frequency is significantly lowered in both ...
Fux Michal - - 2009
The present study focused on the movements that owls perform before they swoop down on their prey. The working hypothesis was that owl head movements reflect the capacity to efficiently follow visually and auditory a moving prey. To test this hypothesis, five tame barn owls (Tyto alba) were each exposed ...
Grierson Lawrence E M - - 2009
This study was designed to examine the importance of vision to corrective processes associated with a mechanical perturbation to the limb during goal-directed aiming. With a hand held stylus, under vision and no vision conditions, performers reached to a target represented by the intersection of perpendicular lines. The stylus was ...
Thyrion Chloé - - 2009
It is generally agreed that motor imagery involves kinesthetic sensations especially as far as first-person imagery is concerned. It was proposed to determine the extent to which motor imagery and vibration-induced illusory sensations of movement are integrated perceptually. Imagined and illusory hand movements were evoked both separately and in various ...
Kazennikov Oleg - - 2009
Music performance is based on demanding motor control with much practice from young age onward. We have chosen to investigate basic bimanual movements played by violin amateurs and professionals. We posed the question whether position and string changes, two frequent mechanisms, may influence the time interval bowing (right)-fingering (left) coordination. ...
Bennequin Daniel - - 2009
Human movements show several prominent features; movement duration is nearly independent of movement size (the isochrony principle), instantaneous speed depends on movement curvature (captured by the 2/3 power law), and complex movements are composed of simpler elements (movement compositionality). No existing theory can successfully account for all of these features, ...
Polyakov Felix F Department of Computer Science and Applied Mathematics, Weizmann Institute of Science, Rehovot, Israel. - - 2009
Some studies suggest that complex arm movements in humans and monkeys may optimize several objective functions, while others claim that arm movements satisfy geometric constraints and are composed of elementary components. However, the ability to unify different constraints has remained an open question. The criterion for a maximally smooth (minimizing ...
Harris Christopher M - - 2009
How should robotic or prosthetic arms be programmed to move? Copying human smooth movements is popular in synthetic systems, but what does this really achieve? We cannot address these biomimetic issues without a deep understanding of why natural movements are so stereotyped. In this article, we distinguish between 'functional' and ...
Pavely Stuart - - 2009
OBJECTIVES: To examine bilateral ball-passing skills whilst running amongst first-grade rugby union footballers. DESIGN: Within-group design SETTING: NSW Rugby Training facilities, Moore Park, Sydney. PARTICIPANTS: One international player used as a case study and twenty, first grade rugby union players. MAIN OUTCOME MEASURES: High-speed film was first used to capture ...
Marinovic Welber W Perception and Motor Systems Laboratory, School of Human Movement Studies, The University of Queensland, Blair Drive, St Lucia 4072, Brisbane, QLD, Australia. - - 2009
Two experiments aimed to provide an estimate of the last moment at which visual information needs to be obtained in order for it to be used to initiate execution of an interceptive movement or to withhold execution of such a movement. In experiment 1, we sought to estimate the minimum ...
Rauzi Matteo - - 2009
It remains largely unknown how large-scale tissue movements during development emerge from the interplay of different tensile forces associated with actomyosin networks. Solon et al. (2009) now report that a ratchet-like mechanism drives the movement of epithelial sheets during dorsal closure in embryos of the fruit fly Drosophila.
Dessing Joost C JC Research Institute MOVE, Faculty of Human Movement Sciences, VU University Amsterdam, Van der Boechorststraat 9, 1081 BT, Amsterdam, The Netherlands. - - 2009
Catching a ball involves a dynamic transformation of visual information about ball motion into motor commands for moving the hand to the right place at the right time. We previously formulated a neural model for this transformation to account for the consistent leftward movement biases observed in our catching experiments. ...
Bradberry Trent J - - 2009
During reaching or drawing, the primate cortex carries information about the current and upcoming position of the hand. Researchers have decoded hand position, velocity, and acceleration during center-out reaching or drawing tasks from neural recordings acquired invasively at the microscale and mesoscale levels. Here we report that we can continuously ...
Stegemöller Elizabeth L - - 2009
Performance of repetitive hand movements in patients with Parkinson's disease (PD) is characterized by slowness, reduced movement amplitude, and hesitation or arrests in ongoing movement. Currently, the factors and mechanisms contributing to impaired performance of these types of movement remain poorly understood. This study examined the effects of movement frequency ...
Moore James W - - 2009
We investigate the processes underlying the feeling of control over one's actions ("sense of agency"). Sense of agency may depend on internal motoric signals, and general inferences about external events. We used priming to modulate the sense of agency for voluntary and involuntary movements, by modifying the content of conscious ...
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