bluuebunny/crossref_metadata_2025 huggingface dataset:
Nonlinear electroacoustic equations for piezoelectric powders
Authors: Pouget J. , Maugin G. A.
Published: October 2005

A nonlinear theory based on the notion of oriented continuum is presented with a view to describing piezoelectric powders. The generalized kinematics comprehends the macroscopic motion of grains as well as the internal deformation (rotation, stretch) of grains (via a so-called director field) in connection with local electromechanical interactions. A complete set of coupled dynamical electroacoustic equations is deduced from first principles for this class of granular media. Thermodynamical arguments then allow one to construct general constitutive equations that exhibit both thermodynamically reversible and irreversible processes. Of necessity, the theory is first constructed in a fully nonlinear framework. In a second stage, the nonlinear equations are perturbed, by means of a Lagrangian variation, about a free finite initial state in which the directors are randomly oriented. These initial privileged directions provoke a local breaking of the ideal symmetry of the material and there results a nonhomogeneous medium. In addition, in the perturbed equations thus obtained, nonlinear terms related to ponderomotive couples and orientational electromechanical couplings are involved. Among the equations obtained, one governs the internal deformations of grains, which materialize in a microgyration of grains about their center of mass and a microstretch in the direction along which the local electromechanical interactions take place. This work collects all the essential ingredients which are required in a study of physically interesting phenomena such as memory echoes in resonant piezoelectric powders.
Scattering of focused ultrasound by spherical microparticles
Authors: Edwards P. L. , Jarzynski J.
Published: October 2005

The scattering of focused ultrasound in water by three different types of microspheres (25–55 μm diameter), with ka<1, was studied. The three scatterers were a spherical glass bubble, solid polystyrene spheres, and hydrogen bubbles. The measurement arrangement consisted of two transducers (transmitter and receiver) of 1.27-cm diameter with focusing lenses mounted on their faces. They were positioned so that their focal regions overlapped and their axes were 60° apart. A swept frequency ultrasonic signal was used, of 30-μs duration, in which the frequency increased linearly from 3.5–6.8 MHz. The glass bubble was mounted on a nylon filament and positioned in the overlapping focal regions. The polystyrene spheres were in solution, and reflections were obtained as they drifted through the focal regions. The hydrogen bubbles were generated by electrolysis and reflections obtained as they rose through the focal regions. From the shape of the echo envelope the frequency dependence of the scattered-pressure amplitude was determined for each scatterer, and significant differences were observed between the echoes from the solid scatterers and the gas bubbles. The experimental results are compared with theoretical predictions.
Supersaturation of complex-amplitude fluctuations of waves propagating in a random medium
Authors: Wenzel Alan R.
Published: October 2005

A theoretical analysis of the wave field radiated by a point source in a one-dimensional random medium is presented. The analysis is based on the quasi-Rytov method, and includes both multiple forward scatter and multiple backscatter effects. An approximate expression for the mean square of the modulus of the fluctuating part of the complex wave amplitude is derived under conditions of a weakly dissipative medium. For the high-frequency case, this expression shows that the complex-amplitude fluctuations increase relatively rapidly with propagation range until a maximum value (the supersaturation value) is reached, after which they decrease relatively slowly with further increase in range. These results are in qualitative agreement with observations of intensity fluctuations of optical waves propagating in the lower atmosphere.
Experimental observations of magneto-acoustic fields
Authors: Moose Paul H. , Klaus Robert F.
Published: October 2005

Experimental observations of electric fields induced in salt water by acoustic waves in a resonant cavity interacting with a strong constant magnetic field are described. The fields are found to behave linearly with the constant magnetic field strength as well as with the acoustic field strength as predicted theoretically. However, the measured electric fields are an order of magnitude greater than predicted by the theory. A similar result has been obtained recently by independent investigators in an open ocean experiment. The discrepancy may be related to the similarity between electromagnetic and acoustic phase velocities in salt water at low frequencies.
Compact sound scatterers with constraints
Authors: Tolstoy I.
Published: October 2005

Lighthill’s method of formulating acoustic scatter allows the explicit introduction of constraints upon the motion of the (small) scatterer. Such constraints can be important in the modeling of rough surfaces by extensions of the Biot technique.
Frequency resolution and discrimination of constant and dynamic tones in normal and hearing-impaired listeners
Authors: Tyler Richard S. , Wood Elizabeth J. , Fernandes Mariano
Published: October 2005

Frequency resolution and three tasks of frequency discrimination were measured at 500 and 4000 Hz in 12 normal and 12 hearing-impaired listeners. A three-interval, two-alternative forced-choice procedure was used. Frequency resolution was measured with an abbreviated psychoacoustical tuning curve. Frequency discrimination was measured for (1) a fixed-frequency standard and target, (2) a fixed-frequency standard and a frequency-transition target, and (3) frequency-transition standard and a frequency-transition target. The 50-ms frequency transitions had the same final frequency as the standards, but the initial frequency was lowered to obtain about 79% discrimination performance. There was a strong relationship between poor frequency resolution and elevated pure-tone thresholds, but only a very weak relationship between poor frequency discrimination and elevated pure-tone thresholds. Several hearing-impaired listeners had normal discrimination performance together with pure-tone thresholds of 80–90 dB HL. A slight correlation was found between word recognition and frequency discrimination, but a detailed comparison of the phonetic errors and either the frequency-discrimination or frequency-resolution tasks failed to suggest any consistent interdependencies. These results are consistent with previous work that has suggested that frequency resolution and frequency discrimination are independent processes.
Propagation of plane waves in a pre-stressed elastic medium
Authors: Norris Andrew N.
Published: October 2005

A homogeneous, isotropic elastic medium having initial axial stresses in two orthogonal directions is considered. The dynamic equations for superimposed small deformations are stated. The propagation of plane waves in such a medium is discussed. It is shown that pure longitudinal and shear waves can propagate only in certain specific directions which are defined. The present analysis corrects a fundamental error in a recent paper in this Journal [J. Acoust. Soc. Am. 72, 255–263 (1982)].
On the use of focused horizontal arrays as mode separation and source location devices in ocean acoustics. Part I: Theory
Authors: Lynch James F.
Published: October 2005

It is shown that one can perform mode separation and source location using a focused horizontal array by utilizing the fact that the system response is greatest to a source located at or near the focal point. This mode separation/source location scheme is discussed for four different physical situations (1) a motionless point cw source in a range invariant environment, (2) a motionless point cw source in a range varying environment, (3) a motionless point broadband source in a range invariant environment, and (4) a moving cw source in a range invariant waveguide environment. Two types of (horizontal) arrays are treated, the line array and the convex circularly curved array. To illustrate the theory, preliminary numerical modeling results are displayed for a line array focused on a motionless point cw source in a range invariant environment.
A miniature electrode for surface electromyography during speech
Authors: Cole Kelly J. , Konopacki Richard A. , Abbs James H.
Published: October 2005

A miniature recessed (i.e., cup) surface EMG electrode intended for use in the perioral region during speech has been constructed and tested. In addition to its small size and low mass, a custom acrylic electrode housing features an extruded design to yield secure attachment to the skin with skin cement rather than with conventional double adhesive collars. A durable, commercially manufactured disk of homogeneous silver and silver chloride was utilized to optimize bioelectric characteristics and durability. In relation to the commonly used fine-wire intramuscular electrode composed of platinum–iridium, this surface electrode demonstrates comparable bioelectric performance in perioral applications including low, stable, and well-matched skin-electrode impedance, a low noise floor, a surprisingly wide bandwidth, and good signal-to-noise ratios.
Noise monitoring in the vicinity of general aviation airports
Authors: Schomer Paul D.
Published: October 2005

In order to examine issues related to noise monitoring in the vicinity of moderate-sized airports, monitoring was performed for 5 months at three sites in the vicinity of the Decatur, Illinois Municipal Airport. The study issues included (1) comparison of predicted and measured day/night average sound levels (DNL), (2) comparison of individual aircraft levels with prediction, (3) temporal sampling requirements for monitoring, and (4) validation that the measured noise is aircraft noise and not other community noise. The measured DNL and the computer predictions compare quite favorably, and most individual aircraft levels compare favorably with data in the FAA computer models. In terms of temporal sampling requirements, it appears that one can use a strategy of choosing four random weeks throughout the year (one from each quarter) to achieve a +2 to −3-dB tolerance. It was not possible to differentiate ‘‘airport’’ noise from other ‘‘community’’ noise. The results show that it may be better (and far less complex) to choose quiet sites where the airport noise predominates and measure only the total daily DNL values.
Use of ‘‘corner microphones’’ for sound power measurements in a reverberation chamber
Authors: Bartel Thomas W. , Yaniv Simone L. , Flynn Daniel R.
Published: October 2005

A comparison was made between acoustic measurements conducted with microphones mounted in the trihedral corners of the 425-m3 NBS reverberation chamber and similar measurements using microphones located in the room interior, away from the room boundaries. Measurements of broadband and discrete-frequency sound pressure and of reverberation time were included. It was found that for frequency bands below the 200-Hz 1/3-octave band, the difference in sound pressure level between the corner and interior locations was, in general, more than 9 dB. In addition, the variations in the broadband steady-state sound pressure level and in the reverberation time were much less among the corners than among the interior locations for frequencies below 100 Hz. It is concluded that for the lower frequency bands, use of the corner locations may reduce systematic errors associated with the interference patterns and provide greater measurement precision because of the lower spatial variance.
Additivity of forward masking
Authors: Neff Donna L. , Jesteadt Walt
Published: October 2005

Masked thresholds for a 1000-Hz sinusoidal signal were measured as a function of masker level in both forward and simultaneous masking for two types of maskers: a 1000-Hz sinusoid and a narrowband noise, 60-Hz wide, centered at 1000 Hz. In forward masking, the noise masker produced much steeper growth-of-masking functions than the sinusoid. Presenting a contralateral broadband noise ‘‘cue’’ with the forward masker dramatically reduced the slope of masking for the noise masker but did not influence results for the sinusoidal masker. The noise remained the more effective masker. The amount of masking produced by combinations of equally effective narrowband-noise and sinusoidal maskers was compared to that produced by each masker individually with and without the contralateral cue. No additional masking beyond that predicted by energy summation was measured for forward masking. Additional masking beyond energy-sum predictions was measured for analogous conditions in simultaneous masking. Comparisons of results obtained with and without the contralateral cue suggest that signal thresholds in the presence of narrowband-noise forward maskers can reflect nonperipheral auditory processes.
Modeling time-delay measurement errors using a generalized beta density function
Authors: Perruzzi Joseph J. , Hilliard E. J.
Published: October 2005

A four-parameter beta density function is employed to model time-delay measurement errors associated with sensor data used in triangulation ranging. This generalized density function allows considerable flexibility in modeling the pertinent error statistics. Specifically, assigning appropriate values to the parameters lead to other symmetric beta, skewed beta, or uniform distributions, all of which can be biased or zero mean. Exploiting a variety of modeling possibilities through parameter selection imparts more realism to the modeling process. The triangulation range density function along with its mean and standard deviation are derived. Comparisons of the pertinent range statistics are made for different measurement error models. Finally, the range statistics associated with the symmetrical beta density function are compared in detail with those statistics obtained from the uniform density function for equivalent values of time-delay measurement error standard deviation.
Measurements on the origin of the wind-dependent ambient noise variability in shallow water
Authors: Wille Peter C. , Geyer Detlef
Published: October 2005

Contributions of environmental quantities related to the noise source field and the propagation path are derived from the comparison of measurements of the wind-dependent noise by omnidirectional receivers at a fixed North Sea station with shipborne measurements in the Baltic Sea. The influence of propagation loss on the wind-dependent shallow water noise appears to be only marginal, even at extremely different sea areas. The quantity governing the noise spectrum level under uncontaminated conditions is the wind speed at the sea surface for which the second power law relation has been verified between 50 Hz and 20 kHz and above a ‘‘threshold’’ wind speed of ≊5 kts. Neither the characteristic height of the sea waves nor the wind turbulence at the reference height are relevant to the noise production, but both may indicate wind profile changes which originate an essential portion of the noise variability for a given wind speed. Further deviations from the second power law are attributed to a bubble layer effect under storm conditions reducing or enhancing the high frequency noise level thus yielding a spread of the average spectrum level of more than 20 dB.
Scattering by a cylinder: A fast exact numerical solution
Authors: Bojarski Norbert N.
Published: October 2005

The known exact analytic solutions to the problem of (acoustic and electromagnetic) scattering by a two-dimensional infinite right circular cylinder are not in closed form, but consist of infinite series, each term of which contains Hankel and Bessel functions of increasing order, and the convergence rate of which decreases rapidly with increasing (ka) numbers. For a given numerical solution, it is thus necessary to compute many Hankel and Bessel functions in high order for each spatial datum point for which the scattered field need be calculated. Presented is an exact numerical method of solution, which is in closed form, and requires the computation of only one Hankel function of order unity per spatial datum point for which the fields need be calculated. The method consists of a closed form numerical deconvolution solution of the scattering integral equation, executed efficiently with the aid of the fast Fourier transform algorithm, thus requiring only ( (3)/(2)  N log2 N) complex arithmetic multiply–add operations, and the computation of only N Hankel functions of order unity, where N is the number of spatial datum points for which a solution is required. Because of the extreme simplicity of the method of solution, a computer program listing for the algorithm is presented. Numerico-experimental results verifying the speed and accuracy of the method are also presented.
Comment on ‘‘Algorithm for extraction of pitch and pitch salience from complex tonal signals’’ [J. Acoust. Soc. Am. 7
1, 679–688 (1982)]
Authors: Martens Jean-Pierre
Published: October 2005

In their paper ‘‘Algorithm for extraction of pitch and pitch salience from complex tonal signals’’ [J. Acoust. Soc. Am. 71, 679–688 (1982)], Terhardt et al. argue that virtual pitch theory can explain the competition between the so-called virtual and spectral pitch percepts evoked by a complex tonal stimulus. In this contribution we formulate some criticisms of essential features of their approach.
Optimal frequencies for meteorological sodar
Authors: Krasnenko N. P. , Odintsov S. L.
Published: October 2005

The expression for the signal-to-noise ratio at the input of a sodar receiver when sounding the boundary layer of the atmosphere has been obtained and investigations of the frequency dependence of this ratio have been made. It is shown that at an acoustic sounding of the atmosphere there are optimal frequencies, corresponding to a maximum of the signal-to-noise ratio, and equations for calculating these frequencies were obtained. Investigations of optimal frequencies of sounding have shown that their values are determined by the geometry of sounding, spectrum of the ambient background noise, and meteorological conditions at the place of sodar operation. The use of carrier frequencies being nonoptimal for the given conditions results in loss in the signal-to-noise ratio and to ineffective use of potential possibilities of sodars.
Measurements of calf liver ultrasonic differential and total scattering cross sections
Authors: Campbell James A. , Waag Robert C.
Published: October 2005

Ultrasonic scattering from calf liver has been measured and normalized to obtain the average differential scattering cross section per unit volume σ̄sd (ν) over scattering angles ν ranging in magnitude from 25 ° to 165 ° and frequencies between 3 and 7 MHz. The results indicate that, at each of the measured frequencies, calf liver is a weak scatterer with nearly one-half of the total scattered power directed between 25 ° and 45 °. The value of σ̄sd (165 °) , which is not expected to differ much from σ̄sd (180 °) , the backscattering coefficient, was found to be approximately 3.7 × 10−6f1.4 mm−1Ω−1, with f in MHz and Ω in steradians. By integrating σ̄sd over all the measured scattering angles to find the total scattering cross section σ̄st , the contribution of scattering loss to attenuation was found to be approximately 2% over the measured frequencies. Analysis of the shape of σ̄sd suggests that the correlation length of the liver was on the order of 1 mm. To assess the accuracy of the normalization method, experimental and theoretical results for σ̄st of a reference medium consisting of glass spheres in agar were compared and found to differ by less than 10%.
Intonation sensitivity for traditional and nontraditional chords
Authors: Roberts Linda A. , Mathews Max V.
Published: October 2005

We studied listeners’ intonation sensitivity to traditional (major and minor) and nontraditional chords. The nontraditional chords have frequency ratios of 3:5:7 and 5:7:9 and, like the major chord, have coincident upper partials and unambiguous fundamental basses. The center tone only of each of these four triads was varied from its just (integer ratio) value by −30, −15, 0, +15, and +30 cents. Each tone had ten partials whose amplitudes decreased with frequency relative to the fundamental (9 dB per octave). Subjects judged which chord (or chordal sequence) of a pair was more in tune, smooth and/or pleasant. Listeners’ intonation sensitivity curves exhibited regular patterns for both traditional and nontraditional chords. However, our subjects divided into two groups: One group preferred chords in just intonation and their preferences decreased monotonically as the intonation deviated from just intonation; the other group preferred intonations that deviated from just intonation by ±15 cents.
The Mid-Ocean Acoustic Transmission Experiment, MATE
Authors: Ewart Terry E. , Reynolds Stephen A.
Published: October 2005

An experiment to measure phase (travel time) and intensity fluctuations in sound pulses transmitted at 2, 4, 8, and 13 kHz over an 18.1 km wholly refracted Fermat path is discussed. Simultaneously with the acoustic monitoring the index of refraction fluctuations were measured in space and time with sufficient resolution to determine the correlation function of the medium. The site was the Cobb Seamount in the northeast Pacific (46°46′N, 130°47′ W), and the time period was 30 days in June–July, 1977. In terms of both the quality and quantity of acoustic and oceanographic measurements, this experiment represents a significant improvement over an earlier experiment in the same location [J. Acoust. Soc. Am. 60, 46–59 (1976)]. The acoustic measurements cover a wider range of acoustic frequencies and more closely represent measurements from a single Fermat path. Approximately 25% of the acoustic data are discussed here; the representations of the correlation function of the index of refraction are based on all of the oceanographic data. The physical processes responsible for the fluctuations in the index of refraction are those due to the tides, internal waves, and finestructure. The effects of internal waves are treated in detail. The moments of the observed intensity fluctuations are discussed, as are the spectral distributions of the second moments of phase and intensity. The observations are compared with theoretical predictions based on the Rytov approximation and on a multiple scatter formulation (approximate solution to the fourth moment equation).
Noise from Arctic Ocean earthquakes
Authors: Keenan Ruth E. , Dyer Ira
Published: October 2005

Earthquakes along the mid-Arctic ridge radiate earthborne compressional and shear waves, which in turn excite the Arctic acoustic channel. These waterborne arrivals, called T waves, have been observed about 300 km from the source and apparently enter the acoustic channel by scattering of vertical rays into nearly horizontal ones by the Arctic ice canopy above the source. The T waves are acoustically energetic (up to 400 kJ), are of surprisingly long duration (up to 72 s at its 8-dB down levels), have low-frequency content (peaks in the 5–15-Hz region), and have haystack spectra (4th power positive and negative dependence below and above the peak frequency, respectively). Characteristics of these sporadic noises are displayed for one event in a sonogram, in short time frequency spectra, in a time series, and in directional spectra. Directional analysis was accomplished with use of a large (∼1 km) two-dimensional horizontal array. Speculations on duration of the observed events suggest that source depth, water-column reverberation above the source, and source magnitude, including ‘‘rapid-fire’’ multiple source excitations, could be the primary causes.
The evaluation of PVF2 for underwater shock-wave sensor application
Authors: Meeks Steven W. , Ting Robert Y.
Published: October 2005

A thick-film polyvinylidene fluoride (PVF2) sample was used to evaluate this material for underwater shock-sensor applications. The free-field voltage sensitivity of the sensor showed a flat frequency response with a bandwidth of 2 MHz. The response of the PVF2 sample to a 1-ms pressure pulse was linear to within 0.6 dB at a peak pressure of 69 MPa. The PVF2 shock sensor also showed reduced high-frequency ringing in its response to a shock wave when compared with a similar device using a PZT element.
Vibratory patterns of the vocal folds during pulse register phonation
Authors: Whitehead Robert L. , Metz Dale E. , Whitehead Brenda H.
Published: October 2005

The purpose of the present study was to investigate the vibratory patterns of the vocal folds during pulse register phonation. Glottal area–time functions were calculated from three high speed laryngeal films (4000 frames/second) obtained during phonation of the schwa vowel in pulse register by a normally hearing and speaking adult female. The results for the first film indicated that each of 35 consecutive vibratory cycles of the vocal folds consisted of a single opening/closing gesture followed by a lengthy closed phase. The analysis of the second film revealed that each of 33 consecutive vibratory cycles consisted of a double opening/closing vocal fold pattern, followed by a long closed phase. For the third film, the results indicated that each of 26 consecutive vibratory cycles of the vocal folds consisted of either a double or triple opening/closing gesture followed by a lengthy closed period. From these data, it appears that one of the physiological descriptors of pulse phonation is multiple, as well as single, vocal fold vibratory patterning.
Interrelation of different oto-acoustic emissions
Authors: Zwicker Eberhard , Schloth Eberhard
Published: October 2005

Amplitude and phase of the sound pressure measured in the closed ear canal during stimulation with pure tones have been monitored as a function of frequency for subjects with and without measurable spontaneous emissions. The frequency spacing between neighboring maxima of the evoked emissions is closely related to that found between neighboring spontaneous emissions. Similar data are found with delayed evoked emissions. All three catagories, spontaneous, delayed, and synchronous evoked emissions are closely related to each other and to the fine structure of threshold in quiet.
Perception of voice-onset-time continua: A signal detection analysis
Authors: Rosner Burton S.
Published: October 2005

An absolute identification task and various discrimination tasks were performed on synthetic syllables initiated by alveolar stops varying in voice-onset-time (VOT). Signal detection analyses of the data yielded three main findings. First, discrimination d′s exceeded those for absolute identification. Greater instability of judgment in the latter than in the former task explained this difference. Second, stimuli within a phonetic category were discriminable, even in a delayed 2IAX paradigm with 4 s between stimuli. Third, a category boundary effect appeared: identification and discrimination d′s were largest around the voiced/voiceless boundary for alveolar stops. The relationship between discrimination and identification d′s varies with response constraints, the number of just noticeable differences in the stimulus array, and stability of judgments in the various tasks. Nearly equal performance in discrimination and identification tasks is not a sufficient condition for a category boundary effect to occur. Several arguments are advanced against a dual-coding model. A continuous model which invokes only a single decision process may account more gracefully for the relationship between identification and discrimination of both consonants and vowels.
Quantitative analysis of the pseudo-Rayleigh phenomenon
Authors: van der Hijden J. H. M. T.
Published: October 2005

Acoustic pseudo-waves (leaky waves) along a plane interface are studied in the space-time domain. Analysis of the Green’s function as derived by the Cagniard–de Hoop method allows a quantitative description of the propagation of a pseudo-Rayleigh pulse along a fluid/solid interface. This includes a condition which limits the range of existence and an equation for the travel speed. A pseudo-Rayleigh factor which determines the relative strength of the phenomenon is defined and the decay of pulsed wave motion along the interface is studied.
Resonant, nonplanar motion of a stretched string
Authors: Miles John
Published: October 2005

The weakly nonlinear, nonplanar, resonant response of a stretched string to simple harmonic, planar excitation is examined in a four-dimensional phase space in which the coordinates are slowly varying amplitudes of a sinusoidal motion of the dominant mode at the driving frequency. There are two similarity parameters, α and β, which measure damping and resonant offset, respectively. The bifurcation points β=β(α), of which there may be as many as eight, of the equilibrium points in the phase space are determined. Two of these points are Hopf bifurcations, which suggests the possibility of bifurcation to a strange attractor, as in the mathematically similar problem for a spherical pendulum. In the present problem, however, there is at least one stable equilibrium point for each pair of α and β, and it appears that the solution of the phase-plane equations always terminates at such a point (which corresponds to harmonic motion of the string). This conclusion is supported by the results of numerical integration. It is shown in an appendix that the equations considered here also describe a large class of nonlinearly coupled, identical oscillators.
Phonemic and phonetic factors in adult cross-language speech perception
Authors: Werker Janet F. , Tees Richard C.
Published: October 2005

Previous research has indicated that young infants can discriminate speech sounds across phonetic boundaries regardless of specific relevant experience, and that there is a modification in this ability during ontogeny such that adults often have difficulty discriminating phonetic contrasts which are not used contrastively in their native language. This pattern of findings has often been interpreted as suggesting that humans are endowed with innate auditory sensitivities which enable them to discriminate speech sounds according to universal phonetic boundaries and that there is a decline or loss in this ability after being exposed to a language which contrasts only a subset of those distinctions. The present experiments were designed to determine whether this modification represents a loss of sensorineural response capabilities or whether it shows a shift in attentional focus and/or processing strategies. In experiment 1, adult English-speaking subjects were tested on their ability to discriminate two non-English speech contrasts in a category-change discrimination task after first being predisposed to adopt one of four perceptual sets. In experiments 2, 3, and 4 subjects were tested in an AX (same/different) procedure, and the effects of both limited training and duration of the interstimulus interval were assessed. Results suggest that the previously observed ontogenetic modification in the perception of non-native phonetic contrasts involves a change in processing strategies rather than a sensorineural loss. Adult listeners can discriminate sounds across non-native phonetic categories in some testing conditions, but are not able to use that ability in testing conditions which have demands similar to those required in natural language processing.
Preindustrial to Modern Interdecadal Variability in Coral Reef pH
Authors: Pelejero Carles , Calvo Eva , McCulloch Malcolm T. , Marshall John F. , Gagan Michael K. , Lough Janice M. , Opdyke Bradley N.
Published: September 2005

The oceans are becoming more acidic due to absorption of anthropogenic carbon dioxide from the atmosphere. The impact of ocean acidification on marine ecosystems is unclear, but it will likely depend on species adaptability and the rate of change of seawater pH relative to its natural variability. To constrain the natural variability in reef-water pH, we measured boron isotopic compositions in a ∼300-year-old massive
Porites
coral from the southwestern Pacific. Large variations in pH are found over ∼50-year cycles that covary with the Interdecadal Pacific Oscillation of ocean-atmosphere anomalies, suggesting that natural pH cycles can modulate the impact of ocean acidification on coral reef ecosystems.
IP
3
Receptor Types 2 and 3 Mediate Exocrine Secretion Underlying Energy Metabolism
Authors: Futatsugi Akira , Nakamura Takeshi , Yamada Maki K. , Ebisui Etsuko , Nakamura Kyoko , Uchida Keiko , Kitaguchi Tetsuya , Takahashi-Iwanaga Hiromi , Noda Tetsuo , Aruga Jun , Mikoshiba Katsuhiko
Published: September 2005

Type 2 and type 3 inositol 1,4,5-trisphosphate receptors (IP
3
R2 and IP
3
R3) are intracellular calcium-release channels whose physiological roles are unknown. We show exocrine dysfunction in IP
3
R2 and IP
3
R3 double knock-out mice, which caused difficulties in nutrient digestion. Severely impaired calcium signaling in acinar cells of the salivary glands and the pancreas in the double mutants ascribed the secretion deficits to a lack of intracellular calcium release. Despite a normal caloric intake, the double mutants were hypoglycemic and lean. These results reveal IP
3
R2 and IP
3
R3 as key molecules in exocrine physiology underlying energy metabolism and animal growth.
Experience-Driven Plasticity of Visual Cortex Limited by Myelin and Nogo Receptor
Authors: McGee Aaron W. , Yang Yupeng , Fischer Quentin S. , Daw Nigel W. , Strittmatter Stephen M.
Published: September 2005

Monocular deprivation normally alters ocular dominance in the visual cortex only during a postnatal critical period (20 to 32 days postnatal in mice). We find that mutations in the Nogo-66 receptor (NgR) affect cessation of ocular dominance plasticity. In NgR
–/–
mice, plasticity during the critical period is normal, but it continues abnormally such that ocular dominance at 45 or 120 days postnatal is subject to the same plasticity as at juvenile ages. Thus, physiological NgR signaling from myelin-derived Nogo, MAG, and OMgp consolidates the neural circuitry established during experience-dependent plasticity. After pathological trauma, similar NgR signaling limits functional recovery and axonal regeneration.
An Old Approach to a Revolutionary Regime
Authors: Shank J. B.
Published: September 2005

Science and Polity in France
. The Revolutionary and Napoleonic Years.
By Charles Coulston Gillispie
. Princeton University Press, Princeton, NJ, 2004. 763 pp. $80, £52.95. ISBN 0-691-11541-9.

In this sequel to his earlier book on science in France at the end of the old regime, the author offers a densely documented account of scientific institutions, personalities, and developments in France between the 1770s and 1820s.
Embedded Nanostructures Revealed in Three Dimensions
Authors: Arslan I. , Yates T. J. V. , Browning N. D. , Midgley P. A.
Published: September 2005

Nanotechnology creates a new challenge for materials characterization because device properties now depend on size and shape as much as they depend on the traditional parameters of structure and composition. Here we show that Z-contrast tomography in the scanning transmission electron microscope has been developed to determine the complete three-dimensional size and shape of embedded structures with a resolution of approximately 1 cubic nanometer. The results from a tin/silicon quantum dot system show that the positions of the quantum dots and their size, shape, structure, and formation mechanism can be determined directly. These methods are applicable to any system, providing a unique and versatile three-dimensional visualization tool.
Astrocytic Purinergic Signaling Coordinates Synaptic Networks
Authors: Pascual Olivier , Casper Kristen B. , Kubera Cathryn , Zhang Jing , Revilla-Sanchez Raquel , Sul Jai-Yoon , Takano Hajime , Moss Stephen J. , McCarthy Ken , Haydon Philip G.
Published: October 2005

To investigate the role of astrocytes in regulating synaptic transmission, we generated inducible transgenic mice that express a dominant-negative SNARE domain selectively in astrocytes to block the release of transmitters from these glial cells. By releasing adenosine triphosphate, which accumulates as adenosine, astrocytes tonically suppressed synaptic transmission, thereby enhancing the dynamic range for long-term potentiation and mediated activity-dependent, heterosynaptic depression. These results indicate that astrocytes are intricately linked in the regulation of synaptic strength and plasticity and provide a pathway for synaptic cross-talk.
Transmembrane Protein GDE2 Induces Motor Neuron Differentiation in Vivo
Authors: Rao Meenakshi , Sockanathan Shanthini
Published: September 2005

During neural development, coordinate regulation of cell-cycle exit and differentiation is essential for cell-fate specification, cell survival, and proper wiring of neuronal circuits. However, the molecules that direct these events remain poorly defined. In the developing spinal cord, the differentiation of motor neuron progenitors into postmitotic motor neurons is regulated by retinoid signaling. Here, we identify a retinoid-inducible gene,
GDE2
(glycerophosphodiester phosphodiesterase 2), encoding a six-transmembrane protein that is necessary and sufficient to drive spinal motor neuron differentiation in vivo. A single amino acid mutation in the extracellular catalytic domain abolishes protein function. This reveals a critical role for glycerophosphodiester metabolism in motor neuron differentiation.
National Character Does Not Reflect Mean Personality Trait Levels in 49 Cultures
Authors: Terracciano A. , Abdel-Khalek A. M. , Ádám N. , Adamovová L. , Ahn C.-k. , Ahn H.-n. , Alansari B. M. , Alcalay L. , Allik J. , Angleitner A. , Avia M. D. , Ayearst L. E. , Barbaranelli C. , Beer A. , Borg-Cunen M. A. , Bratko D. , Brunner-Sciarra M. , Budzinski L. , Camart N. , Dahourou D. , De Fruyt F. , de Lima M. P. , del Pilar G. E. H. , Diener E. , Falzon R. , Fernando K. , Ficková E. , Fischer R. , Flores-Mendoza C. , Ghayur M. A. , Gülgöz S. , Hagberg B. , Halberstadt J. , Halim M. S. , Hřebíčková M. , Humrichouse J. , Jensen H. H. , Jocic D. D. , Jónsson F. H. , Khoury B. , Klinkosz W. , Knežević G. , Lauri M. A. , Leibovich N. , Martin T. A. , Marušić I. , Mastor K. A. , Matsumoto D. , McRorie M. , Meshcheriakov B. , Mortensen E. L. , Munyae M. , Nagy J. , Nakazato K. , Nansubuga F. , Oishi S. , Ojedokun A. O. , Ostendorf F. , Paulhus D. L. , Pelevin S. , Petot J.-M. , Podobnik N. , Porrata J. L. , Pramila V. S. , Prentice G. , Realo A. , Reátegui N. , Rolland J.-P. , Rossier J. , Ruch W. , Rus V. S. , Sánchez-Bernardos M. L. , Schmidt V. , Sciculna-Calleja S. , Sekowski A. , Shakespeare-Finch J. , Shimonaka Y. , Simonetti F. , Sineshaw T. , Siuta J. , Smith P. B. , Trapnell P. D. , Trobst K. K. , Wang L. , Yik M. , Zupančič A. , McCrae R. R.
Published: October 2005

Most people hold beliefs about personality characteristics typical of members of their own and others' cultures. These perceptions of national character may be generalizations from personal experience, stereotypes with a “kernel of truth,” or inaccurate stereotypes. We obtained national character ratings of 3989 people from 49 cultures and compared them with the average personality scores of culture members assessed by observer ratings and self-reports. National character ratings were reliable but did not converge with assessed traits. Perceptions of national character thus appear to be unfounded stereotypes that may serve the function of maintaining a national identity.
Breakdown of Cortical Effective Connectivity During Sleep
Authors: Massimini Marcello , Ferrarelli Fabio , Huber Reto , Esser Steve K. , Singh Harpreet , Tononi Giulio
Published: September 2005

When we fall asleep, consciousness fades yet the brain remains active. Why is this so? To investigate whether changes in cortical information transmission play a role, we used transcranial magnetic stimulation together with high-density electroencephalography and asked how the activation of one cortical area (the premotor area) is transmitted to the rest of the brain. During quiet wakefulness, an initial response (∼15 milliseconds) at the stimulation site was followed by a sequence of waves that moved to connected cortical areas several centimeters away. During non–rapid eye movement sleep, the initial response was stronger but was rapidly extinguished and did not propagate beyond the stimulation site. Thus, the fading of consciousness during certain stages of sleep may be related to a breakdown in cortical effective connectivity.
Nanoscale Imaging of Buried Structures via Scanning Near-Field Ultrasound Holography
Authors: Shekhawat Gajendra S. , Dravid Vinayak P.
Published: October 2005

A nondestructive imaging method, scanning near-field ultrasound holography (SNFUH), has been developed that provides depth information as well as spatial resolution at the 10- to 100-nanometer scale. In SNFUH, the phase and amplitude of the scattered specimen ultrasound wave, reflected in perturbation to the surface acoustic standing wave, are mapped with a scanning probe microscopy platform to provide nanoscale-resolution images of the internal substructure of diverse materials. We have used SNFUH to image buried nanostructures, to perform subsurface metrology in microelectronic structures, and to image malaria parasites in red blood cells.
The “OBS” chart: an evidence based approach to re-design of the patient observation chart in a district general hospital setting
Authors: Chatterjee M T , Moon J C , Murphy R , McCrea D
Published: October 2005

Objective

The primary role of the patient bedside observation chart is to make clinicians aware of the deteriorating patient. Despite this, its performance has not been scrutinised. Many versions exist with different styles of data entry but the optimal format remains elusive. This paper hypothesised that chart design measurably influences function and that redesign and standardisation would improve the detection of physiological decline by clinical staff.

Design

Objective evaluation of existing charts (n = 5), evidence based redesign, and re-evaluation of new chart.

Setting

250 bed district general hospital.

Results

Design of existing observation charts had a significant effect on the ability of clinical staff to detect patient deterioration, with detection rates of parameters indicating physiological decline ranging from 0% to 100%. Graphical plots portrayed information better than written values for all parameters being measured except tachypnoea. No single existing chart was best for all variables. A new chart was designed, implemented with training in its use, and re-evaluated. The new chart also incorporated an early warning scoring system. There were significant improvements in the average detection rates of parameters poorly identified on existing charts: detection rates of tachypnoea and hypoxia increased by 41% (p<0.05) and 45% (p<0.05) respectively. There were also significant improvements in detection rates of tachycardia and fever by 29% (p<0.05) and 16% (p<0.05) respectively.

Conclusion

Evidence based redesign of the patient bedside observation chart coupled with specific training in its use significantly improves the detection of patient physiological deterioration.
ON THE PROBLEM OF THE ISODOUBLET OF THE 2 3S1 MESON NONET
Authors: LI DE-MIN , MA BING , FENG XUE-CHAO , YU HONG
Published: September 2005

Employing three different and complementary approaches, chiral equal-splitting laws, Regge phenomenology and meson–meson mixing, we show that the mass of the isodoublet of the 2 3S1 meson nonet is in the range in 1530–1580 MeV.
GRAVITATIONAL LENSING IN THE WEAK FIELD LIMIT BY A BRANEWORLD BLACK HOLE
Authors: MAJUMDAR A. S. , MUKHERJEE NUPUR
Published: September 2005

The existence of braneworld black holes may be of primordial origin, or may even be produced in high energy particle collisions in the laboratory and in cosmic ray showers as well. These black holes obey a modified mass–radius relationship compared to standard Schwarzschild black holes. Using the variational principle we calculate the bending angle of a light ray near the horizon of a braneworld black hole in the weak field limit. We next derive the expressions of several lensing quantities like the Einstein radius and the magnification for a point light source. These expressions are modified compared to the lensing quantities for standard Schwarzschild black holes and contain the scale of the extra dimensions.
DYNAMICS OF INFLATIONARY COSMOLOGY IN TVSD MODEL
Authors: NASSERI FOROUGH , RAHVAR SOHRAB
Published: September 2005

Within the framework of a model Universe with time variable space dimensions (TVSD), known as decrumpling or TVSD model, we study TVSD chaotic inflation and obtain dynamics of the inflaton, scale factor and spatial dimension. We also study the quantum fluctuations of the inflaton field and obtain the spectral index and its running in this model. Two classes of examples have been studied and comparisons made with the standard slow-roll formulas. We compare our results with the recent Wilkinson Microwave Anisotropy Probe (WMAP) data.
HOW STRONGLY DOES DATING METEORITES CONSTRAIN THE TIME-DEPENDENCE OF THE FINE-STRUCTURE CONSTANT?
Authors: FUJII YASUNORI , IWAMOTO AKIRA
Published: September 2005

We review our argument on the nature of the so-called meteorite constraint on the possible time-dependence of the fine-structure constant, emphasizing that dating meteorites at the present time is different in principle from searching directly for the traces in the past, as in the Oklo phenomenon and the QSO absorption lines. In the related literature, we still find some arguments not necessarily consistent with this difference to be taken properly into account. It does not immediately follow that any model-dependent approaches are useless in practice, though we cannot help suspecting that dating meteorites is no match for the Oklo and the QSO in probing the time-variability of the fine-structure constant, at this moment. Some of the relevance to the QSO data particularly in terms of the scalar field will be discussed.
NEUTRINO PROCESSES IN STRONG MAGNETIC FIELDS AND SUPERNOVA PHYSICS
Authors: DUAN HUAIYU
Published: September 2005

Strong magnetic fields are suspected to exist in some core-collapse supernovae, which would affect the neutrino processes such as νe+n ⇌ e-+p and [Formula: see text]. We briefly review the motion of charged particles in the presence of magnetic fields and the changes of the above processes induced by magnetic fields. We also discuss the implications of these changes for supernova physics in the context of neutrino-driven explosion.
SCHRÖDINGER REPRESENTATION AND SYMPLECTIC EMBEDDING OF TOPOLOGICAL SOLITONS
Authors: HONG SOON-TAE
Published: September 2005

Exploiting the SU(2) Skyrmion Lagrangian with second-class constraints associated with Lagrange multiplier and collective coordinates, we convert the second-class system into the first-class one in the Batalin–Fradkin–Tyutin embedding through the introduction of Stückelberg coordinates. In the enlarged phase space possessing the Stückelberg coordinates, we perform the "canonical" quantization to describe the Schrödinger representation of the SU(2) Skyrmion, so that we can assign via the homotopy class π4( SU (2))=Z2 half integers to the isospin quantum number for the solitons. The symplectic embedding and the Becchi–Rouet–Stora–Tyutin symmetries involved in the SU(2) Skyrmion are also investigated.