Search results for "Ultra"

Effects of prolonged walking on neural and mechanical components of stretch responses in the human soleus muscle

2009

After repeated passive stretching, tendinous tissue compliance increases in the human soleus (SOL) muscle–tendon unit. During movement, such changes would have important consequences for neural and mechanical stretch responses. This study examined the existence of such effects in response to a 75 min walking intervention. Eleven healthy subjects walked on a treadmill at 4 km h−1 with a robotic stretch device attached to the left leg. Ultrasonography was used to measure SOL fascicle lengths, and surface EMG activity was recorded in the SOL and tibialis anterior (TA) muscles. Perturbations of 6 deg were imposed at three different measurement intervals: Pre (immediately before the walking inte…

Application of solid-phase microextraction for determining phenylurea herbicides and their homologous anilines from vegetables.

2004

Abstract Residues of metobromuron, monolinuron and linuron herbicides and their aniline homologous were analyzed in carrots, onions and potatoes by solid-phase microextraction (SPME) performed with a polyacrylate fiber. A juice was obtained from food samples that were further diluted, and an aliquot was extracted after sodium chloride (14%) addition and pH control. At pH 4 only the phenylureas were extracted. A new extraction at pH 11 allowed the extraction of phenylureas plus homologous aniline metabolites. Determination was carried out by gas chromatography with nitrogen–phosporus detection (NPD) the identity of the determined compounds was studied by gas chromatography–mass spectrometry.…

Innenrücktitelbild: Ultrafast Solvent-Assisted Electronic Level Crossing in 1-Naphthol (Angew. Chem. 27/2013)

2013

Inside Back Cover: Ultrafast Solvent-Assisted Electronic Level Crossing in 1-Naphthol (Angew. Chem. Int. Ed. 27/2013)

2013

On the effectiveness of vocal imitations and verbal descriptions of sounds

2014

cote interne IRCAM: Lemaitre14b; None / None; International audience; Describing unidentified sounds with words is a frustrating task and vocally imitating them is often a convenient way to address the issue. This article reports on a study that compared the effectiveness of vocal imitations and verbalizations to communicate different referent sounds. The stimuli included mechanical and synthesized sounds and were selected on the basis of participants' confidence in identifying the cause of the sounds, ranging from easy-to-identify to unidentifiable sounds. The study used a selection of vocal imitations and verbalizations deemed adequate descriptions of the referent sounds. These descriptio…

Linearizing Auditory Distance Estimates by Means of Virtual Acoustics

2008

Auditory distance estimates are not linearly related to physical distances: people tend to overestimate close physical distances, and underestimate far distances [I]. We have modeled a virtual listening environment whose objective is to provide a linear relationship between perceived and physical distance. The simulated environment consists of a trapezoidal membrane with specific absorbing properties at the boundaries. A physics-based model simulates acoustic wave propagation in this virtual space and provides auditory distance cues, namely intensity and direct-to-reverberant energy ratio. Simulations predict the linearity of the psychophysical function relating physical distance to perceiv…

Cumulative-Sum-Based Localization of Sound Events in Low-Cost Wireless Acoustic Sensor Networks

2014

Wireless acoustic sensor networks (WASNs) are known for their potential applications in multiple areas, such as audio-based surveillance, binaural hearing aids or advanced acoustic monitoring. The knowledge of the spatial position of a source of interest is usually a requirement for many of these applications. Therefore, source localization is an important problem to be addressed in WASNs. Unfortunately, most localization algorithms need costly signal processing stages that prevent them from being implemented in low-cost sensor networks, requiring additional modules for signal acquisition and processing. This paper presents a low-complexity method for acoustic event detection and localizati…

Technical Note: Airborne Sound Insulation of Hollow Brickwork

2007

This paper reports on the uncertainty of in situ measurements of the airborne sound insulation of hollow-brick walls in different housing plans, with emphasis on the influence of expansion joints. The mean and standard deviation of multiple measurements are obtained, which show significant differences in insulation values despite the fact that the same construction was used in each case.

Assessment of image quality of intracoronary ultrasound systems with tissue-equivalent vessel phantoms

2002

Imaging of vascular structures by intracoronary ultrasound (ICUS) is finding more and more applications in coronary diagnosis and in the assessment of interventional access. The authors describe a method for easy and quick production of tissue-equivalent vessel phantoms from a special hydrocolloid. The mechanical tolerance is less than 3/100 mm. With these phantoms the authors tested the calibration and measured the resolution properties of the SONOS intravascular ultrasonic system (Hewlett Packard). The measurements revealed a slight space related underestimation of diameters up to 280 /spl mu/m. Using cross correlation and auto correlation functions the authors analyzed digitized ultrason…

On the convergent parts of high order spectral moments of stationary structural responses

1986

The paper deals with the evaluation of the convergent parts of the high spectral moments of linear systems subjected to stationary random input. An adequate physical meaning of these quantities in both the time and frequency domains is presented. Recurrence formulas to obtain the high convergent cross spectral moments of any order are given in the case of white noise input.