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Results 351 - 400 of 1359
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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 ...
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 ...
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 ...
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 ...
Radonjić Ana A Department of Psychology, University of Pennsylvania, Philadelphia, PA 19104, USA. - - 2011
Natural viewing challenges the visual system with images that have a dynamic range of light intensity (luminance) that can approach 1,000,000:1 and that often exceeds 10,000:1 [1, 2]. The range of perceived surface reflectance (lightness), however, can be well approximated by the Munsell matte neutral scale (N 2.0/ to N ...
Llorente-Guillemot Almudena - - 2011
Purpose:  The aim was to assess visual performance after PureVision high addition multifocal contact lens (PM) fitting through contrast sensitivity measured under different illumination levels for both distance and near. Methods:  In a cross-over study, 20 presbyopic patients were randomly assigned to PM or spectacles. Near contrast sensitivity was measured ...
Haburcakova Csilla - - 2012
How the brain processes signals in the presence of noise impacts much of behavioral neuroscience. Thresholds provide one way to assay noise. While perceptual thresholds have been widely investigated, vestibuloocular reflex (VOR) thresholds have seldom been studied and VOR threshold dynamics have never, to our knowledge, been reported. Therefore, we ...
Baranauskas Gytis - - 2011
Extracellular metal microelectrodes are widely used to record single neuron activity in vivo. However, their signal-to-noise ratio (SNR) is often far from optimal due to their high impedance value. It has been recently reported that carbon nanotube (CNT) coatings may decrease microelectrode impedance, thus improving their performance. To tease out ...
Lindner M - - 2011
Handball is one of the top four athletic games with highest injury risks. The jump shot is the most accomplished goal shot technique and the lower extremities are mostly injured. As a basis for ankle sprain simulation, the aim of this study was to extend the ankle region of an ...
Jannati Ali - - 2011
Identification of the second of two targets (T2) is impaired when presented shortly after the first (T1). This attentional blink (AB) is thought to arise from a delay in T2 processing during which T2 is vulnerable to masking. Conventional studies have measured T2 accuracy which is constrained by the 100% ...
Gotoh S - - 2011
We have developed a non-contact stress monitoring system which measures respiratory V(T)/T(I) (tidal volume/inspiration time) alterations using a 10 GHz microwave radar. The measurable distance of the system is 50 cm, which is 10 times longer than our previously developed stress monitoring system which measures heart rate variability using a 24-GHz ...
Pegna R - - 2011
Mechanical oscillators can be sensitive to very small forces. Low frequency effects are up-converted to higher frequency by rotating the oscillator. We show that for 2-dimensional oscillators rotating at frequency much higher than the signal the thermal noise force due to internal losses and competing with it is abated as ...
Chandran R Sriram - - 2011
We demonstrate a method to recover the Young's modulus (E) of a tissue-mimicking phantom from measurements of ultrasound modulated optical tomography (UMOT). The object is insonified by a dual-beam, confocal ultrasound transducer (US) oscillating at frequencies f<sub>0</sub> and f<sub>0</sub> + Δf and the variation of modulation depth (M) in the ...
Killgore J P - - 2011
We demonstrate the accurate nanoscale mapping of near-surface loss and storage moduli on a polystyrene-polypropylene blend with contact resonance force microscopy (CR-FM). These viscoelastic properties are extracted from spatially resolved maps of the contact resonance frequency and quality factor of the AFM cantilever. We consider two methods of data acquisition: ...
Finneran James J - - 2011
Loudness level measurements in human listeners are straightforward; however, it is difficult to convey the concepts of loudness matching or loudness comparison to (non-human) animals. For this reason, prior studies have relied upon objective measurements, such as response latency, to estimate equal loudness contours in animals. In this study, a ...
Kolomietz V M - - 2011
The diffusive non-Markovian motion over a single-well potential barrier in the presence of a weak sinusoidal time modulation is studied. We found nonmonotonic dependence of the mean escape time from the barrier on a frequency of the periodic modulation that is analogous to the stochastic resonance phenomenon. The resonant increase ...
Lemonds D W - - 2011
The auditory filter shape of delphinid odontocetes was previously considered to be typically mammalian constant-quality in which filter bandwidths increase proportionally with frequency. Recent studies with porpoises demonstrate constant-bandwidth portions of the auditory filter. The critical ratios for a bottlenose dolphin were measured between 40 and 120 kHz by behaviorally determining ...
Zhu Ruoyu - - 2011
We report experimental evidence of correlation-induced spectral changes in biological tissues. The overall spectral shift in our transmission measurements is to the red and the mean wavelength of the original spectrum is up 10% larger. These results indicate that the spectral changes due to elastic scattering are significant and likely ...
Katiyar Amit - - 2011
Six models of contrast microbubbles are investigated to determine the excitation threshold for subharmonic generation. The models are applied to a commercial contrast agent; its characteristic parameters according to each model are determined using experimentally measured ultrasound attenuation. In contrast to the classical perturbative result, the minimum threshold for subharmonic ...
Tsai Ming-Ling - - 2011
To evaluate visual function after emergent acceleration stress. Sixteen subjects were enrolled in this study. Human ejection seat trainer was used to induce six times gravitational force in the head-to-toe (z-axis) direction (+6 Gz). Visual performance was evaluated using the visual chart and contrast sensitivity (CS) at indicated times. Ocular ...
Wahlberg Magnus - - 2011
The biosonar pulses from free-ranging northern bottlenose whales (Hyperoodon ampullatus) were recorded with a linear hydrophone array. Signals fulfilling criteria for being recorded close to the acoustic axis of the animal (a total of 10 clicks) had a frequency upsweep from 20 to 55 kHz and durations of 207 to ...
Millot Sandie - - 2011
Piranhas are known to be sound-producing animals. Nevertheless, the biological significance of piranha calls remains unclear because sounds have been recorded only when specimens were held by hand or trapped in a gill net. These sounds are generated by rapid contractions of sonic muscles that insert on a broad tendon ...
Jalilpiran Saber - - 2011
In this Letter, we have introduced a technique, new to our knowledge, to fabricate gratings on a waveguide of azo-functionalized polymeric films using a slit mask and a fast, direct-writing method. To prevent the destruction of the waveguide by the grating formation on the waveguide, we placed a slit mask ...
Hieu Hoang Chi - - 2011
Sum frequency generation (SFG) microscopy images of cotton cellulose fibers were observed at the infrared wavenumber of ∼ 2945 cm(-1) and with a spatial resolution of 2 μm. Domains of different cellulose microfibril bunches were observed and they showed different second-order nonlinear responses. The intensity of the peak of the ...
Martín Helena - - 2011
The brain of migraineurs is hyperexcitable, particularly the occipital cortex, which is probably hypersensitive to light. Photophobia or hypersensitivity to light may be accounted for by an increased excitability of trigeminal, the visual pathways, and the occipital cortex. To study light sensitivity and photophobia by assessing the response to light ...
Nia Hadi Tavakoli - - 2011
Atomic-force-microscopy-based oscillatory loading was used in conjunction with finite element modeling to quantify and predict the frequency-dependent mechanical properties of the superficial zone of young bovine articular cartilage at deformation amplitudes, δ, of ~15 nm; i.e., at macromolecular length scales. Using a spherical probe tip (R ~ 12.5 μm), the ...
Chua Tiffany Elise H TE Department of Biomedical Engineering, University of California, Irvine, California 92697, - - 2011
Current cochlear implants typically stimulate the auditory nerve with biphasic pulses and monopolar electrode configurations. Tripolar stimulation can increase spatial selectivity and potentially improve place pitch related perception but requires higher current levels to elicit the same loudness as monopolar stimulation. The present study combined delayed pseudomonophonasic pulses, which produce ...
Duan Fabing - - 2011
Various situations where a signal is enhanced by noise through stochastic resonance are now known. This paper contributes to determining general conditions under which improvement by noise can be a priori decided as feasible or not. We focus on the detection of a known signal in additive white noise. Under ...
Melton Christopher - - 2011
Dynamic shoulder motion can be captured using video capture systems, but reliability has not yet been established. To compare the reliability of 2 systems in measuring dynamic shoulder kinematics during forward-elevation movements and to determine differences in these kinematics between healthy and injured subjects. Reliability and cohort. Research laboratory. 11 ...
Stoelinga Christophe N J CN Auditory Behavioral Research Lab, University of Wisconsin, Madison, Wisconsin 53706, USA. - - 2011
Spectral density (D), defined as the number of partials comprising a sound divided by its bandwidth, has been suggested as cue for the identification of the size and shape of sound sources. Few data are available, however, on the ability of listeners to discriminate differences in spectral density. In a ...
Verheijen Edwin - - 2011
The Dutch government aims at an increase of wind energy up to 6 000 MW in 2020 by placing new wind turbines on land or offshore. At the same time, the existing noise legislation for wind turbines is being reconsidered. For the purpose of establishing a new noise reception limit ...
Barata Ricardo Andrade - - 2011
Montes Claros in Minas Gerais State, Brazil, was considered an intense transmission area for visceral leishmaniasis. This study evaluated sand fly fauna after insecticide application. Captures were performed in 10 districts from September 2005 to August 2006 with CDC light traps inside and outside each residence. Cypermethrin was sprayed in ...
D'Adamo Juan - - 2011
The wake of a circular cylinder performing rotary oscillations is studied using hydrodynamic tunnel experiments at Re=100. Two-dimensional particle image velocimetry on the midplane perpendicular to the axis of a cylinder is used to characterize the spatial development of the flow and its stability properties. The lock-in phenomenon that determines ...
Stone Michael A MA Department of Experimental Psychology, University of Cambridge, Downing Street, Cambridge CB2 3EB, England. - - 2011
Spectrally shaped steady noise is commonly used as a masker of speech. The effects of inherent random fluctuations in amplitude of such a noise are typically ignored. Here, the importance of these random fluctuations was assessed by comparing two cases. For one, speech was mixed with steady speech-shaped noise and ...
Rozenbaum V M - - 2011
We consider the directed motion of a Brownian particle in a two-well periodic potential with time-varying barriers and wells described by arbitrary periodic functions of time, v(t) and u(t), alternating with the period τ. In the framework of the low-temperature kinetic approach, we obtain explicit formulas for the probabilities of ...
Brown Christopher A - - 2011
Listeners' ability to discriminate interaural time difference (ITD) changes in low-frequency noise was determined as a function of differences in the noise spectra delivered to each ear. An ITD was applied to Gaussian noise, which was bandpass filtered using identical high-pass, but different low-pass cutoff frequencies across ears. Thus, one ...
Chang Natasha A - - 2011
Pairs of unequal strength, counter-rotating vortices were produced in order to examine the inception, dynamics, and acoustic emission of cavitation bubbles in rapidly stretching vortices. The acoustic signatures of these cavitation bubbles were characterized during their inception, growth, and collapse. Growing and collapsing bubbles often produced a sharp, broadband, pop ...
Webb J K - - 2011
We previously reported Keck telescope observations suggesting a smaller value of the fine structure constant α at high redshift. New Very Large Telescope (VLT) data, probing a different direction in the Universe, shows an inverse evolution; α increases at high redshift. Although the pattern could be due to as yet ...
Yokoyama Hidekatsu - - 2011
Direct irradiation of a sample using a quartz oscillator operating at 250MHz was performed for EPR measurements. Because a quartz oscillator is a frequency fixed oscillator, the operating frequency of an EPR resonator (loop-gap type) was tuned to that of the quartz oscillator by using a single-turn coil with a ...
Henninger Heath B - - 2011
BACKGROUND: Lateral offset center of rotation (COR) reduces the incidence of scapular notching and potentially increases external rotation range of motion (ROM) after reverse total shoulder arthroplasty (rTSA). The purpose of this study was to determine the biomechanical effects of changing COR on abduction and external rotation ROM, deltoid abduction ...
Montealegre-Z Fernando - - 2011
This paper describes the biomechanics of an unusual form of wing stridulation in katydids, termed here 'reverse stridulation'. Male crickets and katydids produced sound to attract females by rubbing their forewings together. One of the wings bears a vein ventrally modified with teeth (a file), while the other harbours a ...
Gilson Nicholas D - - 2012
This study assessed the use of standing 'hot' desks in an open plan office and their impact on sedentary work time. Australian employees (n=11; 46.9 [9.8] years; BMI 25.9 [3.5 kg/m(2)]) wore an armband accelerometer for two consecutive working weeks (November-December 2010). In the second week, employees were encouraged to ...
Niazi Imran Khan - - 2011
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. ...
Ammirante Paolo P Ryerson University, Toronto, ON, - - 2012
Common Coding theory predicts that perceived action should resonate in produced action to which it bears some resemblance. Here we show that the qualities of motion commonly attributed to melodies are instantiated in motor plans that control timed movements. Participants attempted to tap a steady beat. Each tap triggered a ...
Lim Soo-Chul SC Human Robot Interaction Research Center, KAIST, Daejeon, - - 2012
Two vibrations with slightly different frequencies induce the beats phenomenon. In tactile perception, when two pins of different frequencies stimulate the fingertips, an individual perceives a beats caused by a summation stimulus of the two vibrations. The present study demonstrates experimentally that humans can perceive another vibration based on the ...
Rodrigues Sharon P - - 2012
It is generally assumed that safety of tissue manipulations during (laparoscopic) surgery is related to the magnitude of force that is exerted on the tissue. To provide trainees with performance feedback about tissue-handling skills, it is essential to define objective criteria for judging the safety of applied forces. To be ...
Halvorsen Kjartan - - 2011
This work studies the immediate effects of altering the vertical displacement of CoM (VD) and step frequency (SF) on the metabolic cost of level treadmill running at 16 km·h on sixteen male runners. Alterations of VD, SF and the product VD SF was induced using a novel feedback system which ...
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