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Results 301 - 350 of 1413
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Yu Na - - 2011
We study the response of two generic neuron models, the leaky integrate-and-fire (LIF) model and the leaky integrate-and-fire model with dynamic threshold (LIFDT) (i.e., with memory) to a stimulus consisting of two sinusoidal drives with incommensurate frequency, an amplitude modulation ("envelope") noise and a relatively weak additive noise. Spectral and ...
Jung Peter - - 2011
In this paper, we discuss the motion of a Brownian particle in a double-well potential driven by a periodic force in terms of energies delivered by the periodic and the noise forces and energy dissipated into the viscous environment. It is shown that, while the power delivered by the periodic ...
Ballart C - - 2011
During July 2007 sand fly captures were carried out in Andorra using sticky castor oil traps set in sand fly resting places for four consecutive nights. The sampling stations were located between 800 and 2400m above sea level. The specimens captured belong to two species of the genus Phlebotomus subgenus ...
Mansfield Neil J - - 2011
Real-world whole-body vibration exposures comprise motion in fore-aft, lateral, and vertical directions simultaneously. There can also be components of roll, pitch, and yaw. If evaluating vibration with respect to human response, most investigators will use methods defined in ISO 2631-1. This uses frequency weightings that were originally derived from laboratory ...
Gavrilov Alexander N - - 2011
Vocal characteristics of pygmy blue whales of the eastern Indian Ocean population were analyzed using data from a hydroacoustic station deployed off Cape Leeuwin in Western Australia as part of the Comprehensive Nuclear-Test-Ban Treaty monitoring network, from two acoustic observatories of the Australian Integrated Marine Observing System, and from individual ...
Thuong Olivier - - 2011
The discomfort of standing people experiencing steady-state vibration can be predicted from the root-mean-square (rms) of the frequency-weighted acceleration, but alternative methods are advocated for evaluating motions containing transients. Using the method of magnitude estimation, 20 standing subjects estimated the discomfort caused by octave-bandwidth random vibrations at two centre frequencies ...
Traer James - - 2011
The passive fathometer algorithm was applied to data from two drifting array experiments in the Mediterranean, Boundary 2003 and 2004. The passive fathometer response was computed with correlation times from 0.34 to 90 s and, for correlation times less than a few seconds, the observed signal-to-noise ratio (SNR) agrees with a ...
Basri Bazil - - 2011
This study determined how backrest inclination and the frequency of vibration influence the perception and discomfort of vibration applied parallel to the back (vertical vibration when sitting upright, horizontal vibration when recumbent). Subjects experienced backrest vibration at frequencies in the range 2.5 to 25 Hz at vibration magnitudes up to 24 dB ...
Konecky Soren D - - 2011
Optical imaging techniques based on multiple light scattering generally have poor sensitivity to the orientation and direction of microscopic light scattering structures. In order to address this limitation, we introduce a spatial frequency domain method for imaging contrast from oriented scattering structures by measuring the angular-dependence of structured light reflectance. ...
Vanderelst Dieter - - 2011
Rhinolophidae or Horseshoe bats emit long and narrowband calls. Fluttering insect prey generates echoes in which amplitude and frequency shifts are present, i.e. glints. These glints are reliable cues about the presence of prey and also encode certain properties of the prey. In this paper, we propose that these glints, ...
Neiman Alexander B - - 2011
Coherence and information theoretic analyses were applied to quantitate the response properties and the encoding of time-varying stimuli in paddlefish electroreceptors (ERs), studied in vivo. External electrical stimuli were Gaussian noise waveforms of varied frequency band and strength, including naturalistic waveforms derived from zooplankton prey. Our coherence analyses elucidated the ...
Zhu Meimei - - 2011
Pitch, timbre, and/or timing cues may be used to stream and segregate competing musical melodies and instruments. In this study, melodic contour identification was measured in cochlear implant (CI) and normal-hearing (NH) listeners, with and without a competing masker; timing, pitch, and timbre cues were varied between the masker and ...
Wojtczak Magdalena - - 2011
The effect of carrier level on tuning in modulation masking was investigated for noise and tonal carriers. Bandwidths of the modulation filters, estimated from the masked detection thresholds using an envelope power spectrum model, were independent of level for the noise carrier but seemed to decrease with increasing level for ...
van Hoesel Richard J M - - 2011
The comparison of measured binaural performance with the better of two monaural measures (one from each ear) may lead to underestimated binaural benefit due to statistical sampling bias that favors the monaural condition. The mathematical basis of such bias is reviewed and applied to speech reception thresholds measured in 32 ...
Grandin Ulf - - 2011
The aims of this study were to investigate spatial patterns and temporal changes in understorey vegetation at four forest catchments forming a depositional gradient. Inventories of the bottom and field layers were carried out in the 1990s and repeated after 5-14 years, depending on catchment. It was hypothesized that changes ...
- - 2011
Climate change is already beginning to affect New York State, and these impacts are projected to grow. At the same time, the state has the ability to develop adaptation strategies to prepare for and respond to climate risks now and in the future. The ClimAID assessment provides information on climate ...
Pataky Todd C - - 2012
Radial force (F(r)) distributions describe grip force coordination about a cylindrical object. Recent studies have employed only explicit F(r) tasks, and have not normalized for anatomical variance when considering F(r) distributions. The goals of the present study were (i) to explore F(r) during tangential force production tasks, and (ii) to ...
Varley Matthew C - - 2011
Abstract In this study, we assessed the validity and reliability of 5 and 10 Hz global positioning systems (GPS) for measuring instantaneous velocity during acceleration, deceleration, and constant velocity while straight-line running. Three participants performed 80 running trials while wearing two GPS units each (5 Hz, V2.0 and 10 Hz, ...
Cai Shi-Duan - - 2011
Simplified phosphorescent organic light-emitting diodes (OLEDs) using only two kinds of hosts and comprising either a neat MoOx hole-injecting layer (HIL) or a MoOx-doped 4,4'-Bis(carbazol-9-yl)biphenyl (CBP) HIL were studied. The devices having the MoOx-doped CBP HIL are superior to the device having the neat MoOx HIL in terms of power ...
Planetta Peggy J PJ Department of Kinesiology and Nutrition, University of Illinois at Chicago, 1919 West Taylor Street, 650 AHSB (M/C 994), Chicago, IL 60612, USA. - - 2012
The tactile motion aftereffect (tMAE) is a perceptual illusion in which a stationary stimulus feels as though it is moving when presented following adaptation to a unidirectionally moving tactile stimulus. Using functional magnetic resonance imaging (fMRI), we localized the brain areas responsive to tactile motion and then investigated whether these ...
Motoyoshi Isamu - - 2011
In contrast to the classical findings of lightness constancy, recent psychophysical studies show the strong dependency of the perceived reflectance of a surface on the structure of the natural illumination. The present study examined this inconstancy for systematic variations in the light field and an image-based explanation for it. Observers ...
Gu Cheng - - 2011
Studies of vibration perception in the glabrous skin of the human hand have identified four mechanoreceptor channels, with each channel showing characteristic variations in thresholds with variations in the frequency of vibration and the area of vibration excitation. To advance understanding of the channels mediating vibration perception on the sole ...
Cheng Hsin-Yi Kathy - - 2012
Plantar fascia stretch plays an important role in the treatment of plantar fasciitis. Existing stretch splints mostly provide stretch to Achilles tendon but not to the plantar fascia. The ones that do are inefficient and uncomfortable because of their static nature. In this paper a dynamic stretch splint featured both ...
Nowroozi B N - - 2011
The vertebral column of fishes has traditionally been divided into just two distinct regions, abdominal and caudal. Recently, however, developmental, morphological, and mechanical investigations have brought this traditional regionalization scheme into question. Alternative regionalization schema advocate the division of the abdominal vertebrae into cervical, abdominal, and in some cases, transitional ...
Lorentzen Jakob - - 2011
OBJECTIVE: Spasticity is a common complication with neurological diseases and CNS lesions. Instrumented systems to evaluate spasticity often cannot provide an immediate result, thus limiting their clinical usefulness. In this study we investigated the accuracy and reliability of the portable Neurokinetics RA1 Ridgidity Analyzer to measure stiffness of the ankle ...
Chung King - - 2011
Abstract Objective: The objectives of this study were: (1) to examine the effect of wide dynamic range compression (WDRC) and modulation-based noise reduction (NR) algorithms on wind noise levels at the hearing aid output; and (2) to derive effective strategies for clinicians and engineers to reduce wind noise in hearing ...
Papadopoulou Konstantina - - 2011
The aim of the present work was to evaluate the biomechanical behaviour of the periodontal ligament (PDL) with respect to force development with different controlled loading velocities. For this purpose, an in vitro experimental study was performed on 18 minipig jaw segments. Displacements with variable increasing loading time were applied ...
Charaziak Karolina K - - 2012
The objective of this study was to compare two recently proposed methods for fast measurements of psychophysical tuning curves (fast-PTCs) in terms of resulting tuning curve features and training effects. Fast-PTCs with swept-noise (SN) and gated-noise (GN) maskers were measured at signal frequencies of 500, 1000, 2000, and 4000 Hz. ...
Wissmann Patrick - - 2011
We present a high-speed and low-cost approach for structured light pattern sequence projection. Using a fast rotating binary spatial light modulator, our method is potentially capable of projection frequencies in the kHz domain, while enabling pattern rasterization as low as 2 μm pixel size and inherently linear grayscale reproduction quantized ...
Tan Zhongwei - - 2011
We present an all-optical passive low-cost spectral filter that exhibits a high-resolution periodic sawtooth spectral pattern without the need for active optoelectronic components. The principle of the filter is the partial masking of a phased array of virtual light sources with multiply jammed diffraction orders. We utilize the filter's periodic ...
Bosten J M - - 2011
Kirschmann's Fourth Law states that the magnitude of simultaneous color contrast increases with the saturation of the inducing surround, but that the rate of increase reduces as saturation increases. Others since Kirschmann have agreed and disagreed. Here we show that the form of the relationship between simultaneous color contrast and ...
Anderson Andrew J - - 2011
Spatial frequency discrimination could simply reflect the ability to discriminate local differences in width when sinusoidal gratings are used. We introduced random fluctuations in the half-cycle widths of both extended 1c/° gratings and those restricted to 1.5 cycles (i.e. two bars of identical phase), as we hypothesised that discrimination for ...
Charalambous Laura - - 2011
Abstract Sprint push-off technique is fundamental to sprint performance and joint stiffness has been identified as a performance-related variable during dynamic movements. However, joint stiffness for the push-off and its relationship with performance (times and velocities) has not been reported. The aim of this study was to quantify and explain ...
Zanca Gisele G - - 2011
Abstract In this study, we evaluated the peak torque, functional torque ratios, and torque curve profile of the shoulder rotators in overhead athletes with impingement symptoms so as to examine possible alterations in response to sports training and shoulder pain. Twenty-one overhead athletes with impingement symptoms were compared with 25 ...
Wu Changwei W - - 2012
Previous studies suggest that spontaneous fluctuations in the resting-state fMRI (RS-fMRI) signal may reflect fluctuations in transverse relaxation time (T(2)(*)) rather than spin density (S(0)). However, such S(0) and T(2)(*) features have not been well characterized. In this study, spatial and spectral characteristics of functional connectivity on sensorimotor, default-mode, dorsal ...
Mastikhin Igor V - - 2011
We demonstrate the combination of oscillating gradient waveforms with single-point imaging techniques to perform measurements of rapidly oscillating and/or rotating fluid motion. Measurements of Fourier components of motion can be performed over a wide range of frequencies, while the immunity of single-point imaging to time-evolution artefacts allows applications to systems ...
Priess Heinz-Werner - - 2011
In three experiments, we tested whether sequentially coding two visual stimuli can create a spatial misperception of a visual moving stimulus. In Experiment 1, we showed that a spatial misperception, the flash-lag effect, is accompanied by a similar temporal misperception of first perceiving the flash and only then a change ...
van Beek Femke E - - 2011
Injuries of horses might be related to the force the rider exerts on the horse. To better understand the loading of the horse by a rider, a sensor was developed to measure the force exerted by the rider on the stirrups. In the study, five horses and 23 riders participated. ...
Blake R W - - 2011
A form of large-amplitude elongated-body theory appropriate for the analysis of undulatory fins attached to a rigid body of elliptical section suggests a benefit due to momentum enhancement relative to the fins on their own. This theoretical prediction is experimentally confirmed for the first time. Theoretical momentum enhancement factors for ...
McClelland Verity M - - 2011
Corticomuscular coherence (CMC) estimation is a frequency domain method used to detect a linear coupling between rhythmic activity recorded from sensorimotor cortex (EEG or MEG) and the electromyogram (EMG) of active muscles. In motor neuroscience, rectification of the surface EMG is a common pre-processing step prior to calculating CMC, intended ...
Pollock Ross D - - 2012
Whole body vibration (WBV) has been suggested to elicit reflex muscle contractions but this has never been verified. We recorded from 32 single motor units (MU) in the vastus lateralis of 7 healthy subjects (34 ± 15.4 yr) during five 1-min bouts of WBV (30 Hz, 3 mm peak to ...
Schneider E - - 2011
A behavioural gap detection paradigm was used to determine the temporal resolution for song patterns by female crickets, Gryllus bimaculatus. For stimuli with a modulation depth of 100% the critical gap duration was 6-8 ms. A reduction of the modulation depth of gaps to 50% led either to an increase or ...
Puts Nicolaas A J - - 2011
The neural mechanisms underlying variability in human sensory perception remain incompletely understood. In particular, few studies have attempted to investigate the relationship between in vivo measurements of neurochemistry and individuals' behavioral performance. Our previous work found a relationship between GABA concentration in the visual cortex and orientation discrimination thresholds (Edden ...
H Maulidiani - - 2011
The metabolites of three species of Apiaceae, also known as Pegaga, were analyzed utilizing 1H NMR spectroscopy and multivariate data analysis. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) resolved the species, Centella asiatica, Hydrocotyle bonariensis and H. sibthorpioides into three clusters. The saponins, asiaticoside and madecassoside, along with ...
Raburn Caroline E - - 2011
Elastic tissues in the human body can store and return mechanical energy passively, reducing the metabolic cost of cyclical movements. However, it is not clear whether humans prefer movement patterns that optimize this storage and return. We investigated the preferred movement pattern during a bouncing task for which non-invasive techniques ...
Koontz Alicia M - - 2011
Laboratory-based simulators afford many advantages for studying physiology and biomechanics however may not perfectly mimic wheelchair propulsion over natural surfaces. The goal of this study was to compare kinetic and temporal parameters between propulsion overground on a tile surface and on a dynamometer. Twenty-four experienced manual wheelchair users propelled at ...
Carr Lucas J - - 2012
Purpose. To examine the accuracy of intensity and inclinometer output of three physical activity monitors during various sedentary and light-intensity activities. Methods. Thirty-six participants wore three physical activity monitors (ActiGraph GT1M, ActiGraph GT3X+, and StepWatch) while completing sedentary (lying, sitting watching television, sitting using computer, and standing still) light (walking ...
Brecht Michael - - 2011
The Etruscan shrew, Suncus etruscus, is not only the smallest terrestrial mammal, but also one of the fastest and most tactile hunters described to date. The shrew's skeletal muscle consists entirely of fast-twitch types and lacks slow fibres. Etruscan shrews detect, overwhelm, and kill insect prey in large numbers in ...
Miersch L - - 2011
Beside their haptic function, vibrissae of harbour seals (Phocidae) and California sea lions (Otariidae) both represent highly sensitive hydrodynamic receptor systems, although their vibrissal hair shafts differ considerably in structure. To quantify the sensory performance of both hair types, isolated single whiskers were used to measure vortex shedding frequencies produced ...
Davies G A GA Joint Department of Physics, Institute of Cancer Research and Royal Marsden NHS Foundation Trust, Downs Road, Sutton, Surrey, SM2 5PT, UK. - - 2011
A model has been developed to simulate volumetric modulated arc therapy (VMAT) delivery for Elekta control systems. The model was experimentally validated for static-tumour VMAT delivery and has been applied to the investigation of motion compensation with dynamic multileaf collimator (dMLC) delivery tracking for a series of VMAT lung treatment ...
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