bluuebunny/crossref_metadata_2025 huggingface dataset:
Geoacoustic inversion and source localization from multisource broadband HLA data
Authors: Neilsen Tracianne B. , MacInnes Craig S. , Knobles David P.
Published: October 2013

In underwater acoustics research, source localization efforts are often hampered by incorrect environmental information, and geoacoustic inversion results can be limited by errors in the source description. In addition, any data set can be contaminated by sound from other acoustic sources in the ocean. To overcome these problems, an iterative rotated coordinates inversion method [T. B. Neilsen, ‘‘An iterative implementation of rotated coordinates for inverse problems,’’ J. Acoust. Soc. Am. (submitted)] is employed in conjunction with a broadband bearing estimator [J. Krolik and D. Swingler, IEEE Trans. Acoust., Speech and Signal Process. 37, (1989)] and matrix filters [C. S. MacInnes, IEEE J. Ocean. Eng. (submitted)] to obtain estimates of the source locations and the sensitive geoacoustic parameters from multisource broadband data received on a horizontal line array (HLA). In the iterative inversion method, subsets of rotated coordinates are used to vary both the source and the sensitive environmental parameters in a series of simulated annealing inversions. The information contained in the rotated coordinates and corresponding eigenvalues determine which parameters are varied significantly in each simulated annealing inversion. [Work supported by ONR.]
Local coupled modes and volume scattering in heterogeneous anisotropic shallow water environments
Authors: Soukup Darin J. , Odom Robert I.
Published: October 2013

Seafloor bottom/subbottom interactions are significant for low frequency acoustic wave propagation in shallow water environments. We investigate the significance of deterministic and stochastic volume scattering for generally anisotropic seafloor bottoms. The following assumptions are made: (i) the model is laterally heterogeneous with an elastic bottom/subbottom, (ii) anisotropy is hexagonally symmetric, (iii) the bottom/subbottom structure is dominated by deterministic elastic moduli with additional small-scale stochastic variations. The local coupled mode rough interface scattering theory of Park and Odom [Geophys. J. Int. 136, 123 (1999)] is extended by including volume scattering terms. New volume scattering terms are derived by applying perturbation theory to the elastic equations of motion. The acoustic wavefield is expressed as a sum of a mean deterministic wavefield and a small-scale scattered wavefield. Perturbations in the elastic moduli contribute to energy loss and the loss of signal coherence. The local mode formalism brings insight into the efficiency of volume scattering by indicating directly how much energy of coherent mode q is redistributed into scattered mode r. Numerical calculations indicating the effects of volume scattering are presented. [Work supported by ONR.]
The application of smart structures toward feedback suppression in amplified acoustic guitars
Authors: Griffin Steven F. , Lane Steven A. , Clark Robert L.
Published: October 2013

Smart structures technology can be applied to amplified acoustic guitars to prevent instability resulting from acoustic feedback. This work presents a coupled model of the guitar dynamics and the acoustic feedback mechanism, and explains how a simple control loop using a piezoceramic actuator can be used to reduce the effects of acoustic feedback. In addition to model simulations, experimental results using a real system and a simple controller are presented. The results show that a significantly higher (7-dB) guitar output can be achieved before instability, without detrimentally affecting the amplified and un-amplified guitar response.
Variability and reduced performance of preschool- and early school-aged children on psychoacoustic tasks: What are the relevant factors?
Authors: Allen Prudence
Published: October 2013

Young children typically perform more poorly on psychoacoustic tasks than do adults, with large individual differences. When performance is averaged across children within age groups, the data suggest a gradual change in performance with increasing age. However, an examination of individual data suggests that the performance matures more rapidly, although at different times for different children. The mechanisms of development responsible for these changes are likely very complex, involving both sensory and cognitive processes. This paper will discuss some previously suggested mechanisms including attention and cue weighting, as well as possibilities suggested from more recent studies in which learning effects were examined. In one task, a simple frequency discrimination was required, while in another the listener was required to extract regularities in complex sequences of sounds that varied from trial to trial. Results suggested that the ability to select and consistently employ an effective listening strategy was especially important in the performance of the more complex task, while simple stimulus exposure and motivation contributed to the simpler task. These factors are important for understanding the perceptual development and for the subsequent application of psychoacoustic findings to clinical populations. [Work supported by the NSERC and the Canadian Language and Literacy Research Network.]
A review of the pertinent measurements and equations for small room acoustics
Authors: Jones Douglas
Published: October 2013

Confusion about the appropriate measurements and calculations for use in small room acoustics persists. This paper presents an overview of the most important calculations to predict performance during the design phase and the most useful measurements to verify or troubleshoot performance after the facility is constructed. Special attention will be paid to the importance and relevance of reverberation in small rooms.
Listening to sound patterns as a dynamic activity
Authors: Jones Mari Riess
Published: October 2013

The act of listening to a series of sounds created by some natural event is described as involving an entrainmentlike process that transpires in real time. Some aspects of this dynamic process are suggested. In particular, real-time attending is described in terms of an adaptive synchronization activity that permits a listener to target attending energy to forthcoming elements within an acoustical pattern (e.g., music, speech, etc.). Also described are several experiments that illustrate features of this approach as it applies to attending to musiclike patterns. These involve listeners’ responses to changes in either the timing or the pitch structure (or both) of various acoustical sequences.
Probabilistic geoacoustic inversion
Authors: Dosso Stan
Published: October 2013

The problem of estimating seabed geoacoustic parameters from ocean acoustic measurements has received considerable attention in recent years. Geoacoustic inversion represents a convenient alternative to direct measurements (e.g., coring) and provides sensitivity relevant to acoustic source localization applications; however, it requires solving a strongly nonlinear inverse problem. A variety of approaches have been developed (by a number of researchers) based on seeking geoacoustic parameters that provide the optimal match to measured acoustic fields using global search techniques. Other approaches include inversion of bottom-loss or seabed-reflectivity data and ambient noise. Topics of current interest include range-dependent inversion, coherent spatial/temporal processing, and uncertainty estimation. This paper reviews the above approaches in terms of a general probabilistic formulation for geoacoustic inversion. The goals of the probabilistic approach are to fit the acoustic data and available prior information to within their uncertainties, and to estimate geoacoustic parameters, their uncertainties, and inter-relationships. This is accomplished using a Bayesian formulation and Markov chain Monte Carlo approach (Gibbs sampling) to extract features of the posterior probability density such as the maximum a posteriori estimate, marginal probability distributions, and correlations. The approach is illustrated for matched-field inversion, inversion of seabed reflectivity, and source localization with environmental uncertainty.
Developmental MLD effects
Authors: Buss Emily , Hall Joseph W. , Grose John H.
Published: October 2013

Whereas the masking-level difference (MLD) in children is similar to that found in adults for wideband masking noise, children often have smaller MLDs for narrowband noise maskers. One possibility is that the small MLD of children in narrowband noise is related to the pronounced amplitude fluctuation of the masker. In the present study, adults and children (aged 5.1 to 10.7 years) were tested in an MLD paradigm in which the detection of brief signals was contrasted for signal placement in masker envelope maxima versus masker envelope minima. Maskers were 50-Hz wide noise bands centered on 500 Hz, and the signals were So or S〈pi〉 30-ms, 500-Hz tones. In agreement with previous studies, it was found that MLDs were greater for masker envelop minima placement than for masker envelope maxima placement. This effect was due to variation across the S〈pi〉 conditions. The results indicated that young children are relatively poor in taking advantage of the relatively good signal-to-noise ratios in masker minima when detecting S〈pi〉 signals in No maskers. This finding is consistent with the possibility that binaural temporal resolution continues to develop through the first decade of life.
Relating double slope decay in coupled volumes with volume ratio, absorption ratio, and aperture size
Authors: Bradley David T. , Wang Lily M.
Published: October 2013

Coupled volumes typically consist of two spaces connected through an opening known as a coupling aperture. If the absorption characteristics in the auxiliary space are such that its decay time is longer than that of the main space, late-arriving energy will be fed back into the main space by the secondary volume. This energy coupling leads to the phenomenon known as the double slope decay. This project uses computer modeling to study the effect of three architectural variables on the double slope profile from a simple coupled volume system. The three variables studied are the volume ratio between the main and secondary space, the absorption ratio between the two spaces, and the aperture size. The resulting energy decay profiles are categorized according to their degree of double slope behavior and cross-referenced with the independent variables. Quantitative results from this analysis are presented.
Phonological systems in bilinguals: Age of learning effects on the stop consonant systems of Korean-English bilinguals
Authors: Kang Kyoung-Ho , Guion Susan G.
Published: October 2013

The stop systems of adult Korean (L1)-English (L2) bilinguals were studied through acoustic analysis of Korean and English stop productions. The interaction of the first and second language stop systems was investigated as a function of age of exposure to English. The main goals of the investigation were to examine the extent to which early and the late bilinguals produced a given stop category in a native-like way and the extent to which the two stop systems were held independent from each other in the phonological systems of the bilinguals. Two specific questions were asked: whether early bilinguals were more native-like in the production of English stops and thus were more likely to establish L2 phonetic categories than late bilinguals, and whether the Early bilinguals maintain a greater extent of independence between the Korean and English stop systems than the late bilinguals. For this purpose, productions of Korean and English stops were analyzed in terms of three acoustic-phonetic properties, VOT, H1−H2, and f0. The results suggested that fine-grained phonetic information is crucial to investigation of bilingual phonological systems and they were discussed in terms of the role of perceived phonetic distance between L1 and L2 phonetic categories in L2 speech learning.
Ground-truthing evoked potential measurements against behavioral conditioning in the goldfish, Carassius auratus
Authors: Hill Randy J. , Mann David A.
Published: October 2013

Auditory evoked potentials (AEPs) have become commonly used to measure hearing thresholds in fish. However, it is uncertain how well AEP thresholds match behavioral hearing thresholds and what effect variability in electrode placement has on AEPs. In the first experiment, the effect of electrode placement on AEPs was determined by simultaneously recording AEPs from four locations on each of 12 goldfish, Carassius auratus. In the second experiment, the hearing sensitivity of 12 goldfish was measured using both classical conditioning and AEP’s in the same setup. For behavioral conditioning, the fish were trained to reduce their respiration rate in response to a 5 s sound presentation paired with a brief shock. A modified staircase method was used in which 20 reversals were completed for each frequency, and threshold levels were determined by averaging the last 12 reversals. Once the behavioral audiogram was completed, the AEP measurements were made without moving the fish. The recording electrode was located subdermally over the medulla, and was inserted prior to classical conditioning to minimize handling of animal. The same sound stimuli (pulsed tones) were presented and the resultant evoked potentials were recorded for 1000–6000 averages. AEP input–output functions were then compared to the behavioral audiogram to compare techniques for estimating behavioral thresholds from AEP data.
High trace-velocity events associated with auroral activity in Alaska
Authors: Wilson Charles R. , Olson John V.
Published: October 2013

Data from the CTBT/IMS station 153US at Fairbanks, AK covering 2003 and 2004 have been surveyed for high-correlation, high trace-velocity events. Although such events have been detected at all times of the day the distribution shows a strong maximum in the morning hours (near 15UT) and a weaker maximum in the evening hours (near 5UT). Twenty intervals containing high trace-velocity events from 2003 and 37 intervals from 2004 have been studied in detail. The intervals containing high trace-velocity events can last from a few hours up to 10 hours. All-sky video records show that the high trace-velocity events are associated with stable, pulsating auroral patches that occur during the recovery phase of substorms. This talk will review the characteristics of the high trace-velocity events and the associated auroral video where available.
Fundamental frequency discrimination and harmonic resolvability in sensorineural hearing impariment
Authors: Bernstein Joshua G. W. , Oxenham Andrew J.
Published: October 2013

Sensorineural hearing loss (SNHL) often results in impaired fundamental frequency (F0) processing. Three experiments tested the hypothesis that this deficit is related to a loss of frequency selectivity, which may result in fewer peripherally resolved harmonics. F0 difference limens (F0DLs) were measured as a function of F0 for bandpass filtered sine- and random-phase harmonic complexes in listeners with mild-to-moderate SNHL. All listeners showed a transition between small (good) F0DLs at high F0s and large (poor) F0DLs at low F0s, although the transition point varied across subjects. Two measures that are thought to reflect frequency selectivity generally corresponded to the F0DL transition point: the maximum F0 for which F0DLs were phase-dependent, and the minimum modulation frequency required to discriminate amplitude modulation from quasi-frequency modulation. These results provide some support for the idea that the F0-processing deficit associated with SNHL is related to poor frequency selectivity. However, contrary to our hypothesis, poor correspondence was observed between the F0DL transition point and auditory filter bandwidths estimated using the notched-noise method in the same subjects. This suggests a possible discrepancy between traditional spectral-masking estimates of frequency selectivity and estimates based on temporal interactions between unresolved components. [Work supported by NIH grants R01DC05216 and 5T32DC00038.]
Criteria for multiple noises in residential buildings using combined rating system
Authors: Jeon Jin Yong , Ryu Jong Kwan , Jeong Young
Published: October 2013

Multiple residential noises such as floor impact, air-borne, bathroom, drainage, and traffic noises were classified using a combined rating system developed from a social noise survey and auditory experiments. The effect of individual noise perception on the evaluation of the overall noise environment was investigated through a questionnaire survey on annoyance, disturbance, and noise sensitivity. In addition, auditory experiments were undertaken to determine the allowable sound pressure level for each residential noise source and the percent satisfaction for individual noise levels. From the results of the survey and the auditory experiments, a combined rating system was developed and annoyance criteria for multiple residential noises were suggested.
Source localization in complex scattering environments using random amplitude and bearing information
Authors: Wilson D. Keith , Moran Mark L. , Greenfield Roy
Published: October 2013

By scattering sound waves, atmospheric turbulence and other outdoor objects (such as building and trees) induce random fading and angle-of-arrival variations in signals received by small-baseline microphone arrays. This study addresses the relative utility of signal amplitude and bearing estimates when such variations are present. Source-localization simulations are performed for four idealized statistical scattering models: no scattering, weak turbulent scattering, strong turbulent scattering, and diffuse (multiple) scattering. Each of these cases is considered with low, moderate, and high SNR. It is found that bearing information provides highly accurate source localization when SNR is high and scattering is negligible. However, when the SNR is low and/or there is significant scattering, the bearing information loses its utility while the amplitude information remains relatively robust. Algorithms are considered that attempt to assess the relative reliability of the bearing and amplitude information, and subsequently weight signal features to provide the most satisfactory results. The simulations also confirm previous analyses suggesting that, for unfavorable propagation conditions and SNR, Cramer-Rao lower bounds predict substantially better performance than is obtainable in practice.
A focused multi-layered spherical shell with guided wave enhancements
Authors: Smith John D. , Williams Duncan P.
Published: October 2013

There is a continued need for underwater reflective targets to be used as relocation and navigational aids. Traditionally, fluid-filled thin spherical shells have been used as passive reflectors, similar to cat’s eyes, and would usually be filled with liquid chloroflourocarbons (CFC’s). Other options are needed now that the production of CFC’s has been restricted. This paper looks at the relationship between a system of multi-layered concentric elastic shells and their target strength in water. The problem is formulated using the global matrix method and is applicable to any system with an arbitrary number of layers. Results show that, by using certain combinations of low loss elastic layers together, the target strength is higher than it would be for any one of the materials used in isolation. This result is explained by geometric focussing on the back surface of the sphere and guided elastic waves that circumnavigate the outer layer or shell and enhance the focussing. The results are compared with calculations and existing experiments for a stainless steel shell filled with CFC.
The discrimination of interaurally correlated noise bands
Authors: Edmonds Barrie , Culling John
Published: October 2013

Models of binaural unmasking suggest that the auditory system detects deviations from unity in the interaural coherence of the waveforms at the two ears. Since anticorrelated noise has high coherence within a frequency channel, such a coherence-detection mechanism should be unable to distinguish a correlation of −1.0 from a high positive correlation. A 3I-2AFC paradigm was used to test whether such a limitation can be observed behaviorally. Stimuli consisted of a 1-ERB-wide sub-band of interaurally correlated noise centered at 500 Hz (i.e. 462–538 Hz) flanked by two spectrally remote bands of noise (0–329 Hz and 717–3000 Hz) with an interaural correlation of 1.0. The flanking bands were intended to reduce cues from the perceived laterality of the stimuli. Participants were presented with three stimuli (reference, target, and distracter) and asked to choose the odd-one-out: the reference and distracter intervals contained sub-bands of anticorrelated noise while the target interval contained a sub-band of noise with interaural correlation between 0.7 and 1.0. Preliminary results indicate that different participants find different values of interaural correlation to be more distinguishable than others.
Acoustically-guided articulation patterns for vowel production
Authors: Story Brad
Published: October 2013

The purpose of this study was to investigate the link between the vocal tract deformation patterns obtained from statistical analyses of articulatory data (i.e., measured area functions) and the acoustic properties of a realistic neutral vocal tract shape. The starting point was a previously reported statistical analysis (i.e., PCA) of a speaker-specific set of measured vowel area functions. It resulted in a mean area function, and two basis functions that perturb the vocal tract into vowel-like shapes. In the present study, acoustic sensitivity functions were calculated for the same mean area function. Then, four separate sum and difference combinations of the sensitivity functions were used directly to perturb the mean area function. The results showed that these sum and difference combinations created deformation patterns with nearly the same variation along the vocal tract length as the basis functions derived from articulatory data. The procedure was then applied to other speaker-specific sets of area functions and the results were similar. [Work supported by NIH R01-DC04789.]
An acoustic study of Deg Xinag fricatives
Authors: Wright Richard , Hargus Sharon , Miller Julia
Published: October 2013

Few studies have looked at the acoustic properties of fricatives in Native American languages. Notable exceptions are McDonough (2003) on Navajo, and Gordon, Barthmaier, and Sands (2002), which examined a variety of languages, including several Native American ones. In Deg Xinag, an endangered Athabaskan language spoken in Alaska, there are eight places of articulation for voiceless fricatives [a relatively large phonetic inventory, according to Maddieson (1984)], including some rarely studied place contrasts (e.g. alveolar versus retroflex). In this study, pre- and post-vocalic fricatives were digitally recorded in the field from eight speakers (two males, six females) using a head-mounted mic to control for distance from the source. The segmental context was also controlled for, the neighboring vowel being [a] in all cases. Each speaker produced four repetitions of each word. The first four spectral moments, lowest spectral peak, and the three loudest spectral peaks were measured at the midpoint of each fricative, and each speaker’s average for each of the measures was calculated. In this poster, qualitative results in the form of spectrographic analysis will be presented. Repeated measures ANOVA for each of the quantitative measures will also be presented. [Work supported by NSF.]
Learning on auditory discrimination tasks in normal-hearing listeners: Implications for hearing rehabilitation
Authors: Wright Beverly A.
Published: October 2013

Hearing rehabilitation extends beyond simply fitting a hearing aid or cochlear implant. To improve the benefit of these devices, it must be established which auditory abilities can be improved with training. Toward this end, learning in normal-hearing listeners was examined on five auditory discrimination tasks: frequency, intensity, interaural-time-difference (ITD), interaural-level-difference (ILD), and duration. Because the same training regimen was used throughout, any differences in the learning patterns across these trained discriminations likely reflect differences in the plasticity of the underlying mechanisms, at least for that regimen. The influence of training was assessed by comparing the improvements in discrimination threshold on trained and untrained conditions between listeners who were given multiple-hour practice on a single discrimination condition and those who were not. Learning on the five tasks followed one of two general patterns. For ITD and intensity discrimination, multiple-hour practice did not lead to greater learning than that seen in untrained listeners. In contrast, for ILD, duration, and frequency discrimination, such practice yielded greater learning, but only on a subset of conditions. The differences in the plasticity across these auditory tasks in normal-hearing listeners imply that cochlear-implant users may benefit more from training on some tasks than others. [Work supported by NIH.]
Techniques in piezoelectric transducer health monitoring
Authors: Hughes Eli M. , Reichard Karl M. , Gabrielson Tom B.
Published: October 2013

For many high intensity underwater applications, the piezoelectric elements within a transducer can be placed under high thermal, electrical and mechanical stress. One particular area of piezoelectric transducer research that has received little attention is in-situ health monitoring and failure prediction of the piezoelectric elements. While some studies have been performed in the theoretical mechanics of fractures due to device stress, there is a lack of practical information about piezoelectric health monitoring and failure prediction. This study was directed at providing practical information about a transducer’s electrical characteristics as it is stressed such that failure predictions can be made. The two major failure modes examined in this study were electro-mechanical stress and thermal depolarization. A large part of this research was devoted to the development of novel low-cost electronics that permit measurement of the broad band electrical impedance of the device from 0 to 50 kHz in a small time aperture. The new measurement techniques allow for a large amount of visibility in how a transducer’s electrical impedance changes before and during failure. This added visibility provides information that can be used to accurately predict if a transducer is failing and what mechanism is causing the failure.
Contrast-enhanced detection of arterial bleeding
Authors: Luo Wenbo , Zderic Vesna , Starr Frank , Paun Marla , Vaezy Shahram
Published: October 2013

The purpose of this study was to determine the feasibility and usefulness of contrast agent to detect internal bleeding. In a model of acute femoral artery injury, bleeding sites were produced percutaneously in 9 rabbits, using an 18 G needle guided by Doppler and B-mode ultrasound. Imaging was performed pre- and post-injury and after i.v. injection of contrast agent (Optison) using B-mode, Color Doppler (CD), and Pulse Inversion. Gross and histological examination (light microscopy) of the injured blood vessel and the surrounding tissue were performed. Experiments with similar procedure were achieved in a pulsatile phantom with carotid arteries as targeted blood vessels in vitro. Bleeding sites could not be located in non-contrast B-mode sonography. After administration of contrast agent, injuries could be detected by the increased echogenicity of the extravasated blood flow. The resulted hematoma appeared as inhomogeneous hyper-echo region. Color mosaic patterns were observed in the surrounding tissue with CD. Cluster of cavities were found within hematoma upon microscopy, which may be due to aggregated microbubbles. Bleeding sites were recognized in all contrast studies by CD; compared with only 11% in non-contrast control. Contrast-enhanced sonography is a promising tool in detection and evaluation of internal bleeding.
Consonantal perturbations of pitch in Halkomelem Salish
Authors: Brown Jason , Thompson James J.
Published: October 2013

It has long been noted that consonants have an effect on the pitch of a following vowel: voiceless stops tend to raise F0, while voiced stops lower it. It has also been suggested that the duration of such perturbations is shorter in tone languages than in non-tone languages [Hombert, Studies in African Linguistics (1977)]. This study compares the effects that consonants have on F0 in two closely related Salish languages: Island Halkomelem, a non-tone language, and Upriver Halkomelem, a language that has reportedly undergone some limited tonogenesis but offers no clear prosodic clues regarding tonality. The effects of the voiceless and ejective stop series were observed, and measurements of F0 were taken at the onset of voicing for the vowel, then at 20 msec. intervals up to 100 msec. Preliminary results indicate that i) Island Halkomelem shows a greater magnitude of difference in F0 at vowel onset between the voiceless and ejective stops than Upriver Halkomelem, and ii) Island Halkomelem shows greater durations of consonantal perturbations of F0 than does Upriver Halkomelem. This suggests that Upriver Halkomelem may have become more sensitive to pitch than the Island dialect, supporting the interpretation of this language as tonal. [Work supported by Phillips Fund.]
Automatic 3D acoustic tissue models from histologic tissue sections and application to ex vivo tissue characterization
Authors: Mamou Jonathan , Oelze Michael L. , O’Brien William D. , Zachary James F.
Published: October 2013

Three-dimensional acoustic tissue models (3DATMs) can be used as computational tools for ultrasonic imaging algorithm development and analysis. 3DATMs are automatically constructed from digitized light microscope images of consecutive H&E-stained histologic tissue sections. Construction necessitated contrast equalization, registration, and interpolation of missing sections. The registered (with interpolated) sections yield a 3D histologic volume (3DHV). Acoustic properties are then assigned to each tissue constituent of the 3DHV to obtain the 3DATM. A tissue characterization technique was developed to obtain scatterer parameter estimates (size and acoustic concentration) from a 3D impedance map (3DZM) deduced from a 3DHV by assigning acoustic impedance values. 3DZMs were constructed for a rat fibroadenoma (FA), a mouse mammary tumor (MMT) and a mouse sarcoma (EHS). From these 3 3DZMs estimates, effective scatterer diameters of 91 μm, 31.5 μm, and 34.5 μm, respectively, were determined. Independent ultrasonic measurements yielded average scatterer diameters of 105 μm, 30 μm, and 33 μm, respectively. The 3DZM estimation scheme showed results similar to those obtained by the ultrasonic measurements. 3DATMs may therefore be a useful tool for quantifying ultrasonic tissue properties. [Work supported by the University of Illinois Research Board.]
Relationship between fundamental and formant frequencies in speech perception
Authors: Assmann Peter F. , Nearey Terrance M.
Published: October 2013

In natural speech, there is a moderate correlation between fundamental frequency (F0) and formant frequencies, associated with differences in larynx and vocal tract size across talkers. We have manipulated these properties using the Kawahara’s STRAIGHT vocoder to determine their contribution to sentence intelligibility, vowel identification accuracy, perceived gender, and naturalness judgments by human listeners. The results of these experiments, together with predictions from a pattern recognition model, suggest that frequency-shifted speech is more intelligible and perceived as more natural when the natural co-variation of F0 and formant frequency is preserved, even when frequency shifts exceed the range found in human speech.
Psychometric-function slopes for forward-masked tones in listeners with cochlear hearing loss
Authors: Schairer Kim S. , Messersmith Jessica , Jesteadt Walt
Published: October 2013

Slopes of psychometric functions (PF) for forward-masked tones in normal-hearing (NH) listeners decrease as a function of signal threshold in both on- and off-frequency masker conditions. This result is attributed to nonlinear cochlear response growth, and has been used to demonstrate comparable compression at 4000 and 250 Hz. The current study further tested the hypothesis that the slope effect is due to nonlinearity. In hearing-impaired (HI) listeners who presumably lack cochlear nonlinearity, PF slopes should remain steep across signal threshold levels. Four NH and six HI listeners with a range of hearing thresholds were tested in on- and off-frequency masker conditions, with signals of 4000 and 250 Hz. Otoacoustic emissions were measured to verify absent or decreased cochlear nonlinearity in the HI listeners. In general, PF slopes were steeper for the HI than NH listeners. One subject had normal hearing at 250 Hz, and hearing loss at 4000 Hz. Her PF slopes were comparable to the mean slopes across NH subjects in the 250-Hz signal conditions, but were elevated in comparison to the NH subjects in the 4000-Hz conditions. These results are consistent with predictions from a model of forward masking that incorporates cochlear nonlinearity as one of its stages.
Conditions for evoked-potential audiometry in odontocetes
Authors: Supin Alexander Ya.
Published: October 2013

Currently auditory brainstem evoked potentials (ABR) become widely used for audiometry in odontocetes. Depending on the goal, the ABR technique differs with respect of (i) electrode positions, (ii) stimulus parameters, and (iii) threshold evaluation procedure. (I) Optimal electrode positions are vertex (for binaural responses), lateral (for monaural responses), or pharyngeal (for some express investigations). (II) The shorter the stimulus and the wider its spectrum, the more robust the response. Thereafter, narrow-band stimuli provoke low-amplitude ABR with a short dynamic range, but the goal of investigation often requires keeping the stimulus spectrum narrow. Sinusoidally amplitude modulated (SAM) sounds have narrow spectra, thereby provoking low amplitude envelope-following response (EFR); however, EFR can be extracted from noise by Fourier analysis. Modulation rate for SAM sounds must fit a spectrum peak of the ABR waveform. High-frequency sounds are more effective to provoke ABR and EFR than low-frequency ones, so ABR technique is better applicable for measurements in high-frequency ranges. (III) For precise threshold evaluation, low-amplitude responses must be extracted from noise. Apart from the averaging procedure, cross-correlation (for single ABR) or Fourier (for EFR) analysis is helpful to extract and measure low response amplitudes. [Work supported by Russian Basic Research Foundation, Russian President Grant, ONR.]
Reconstructing Geographical Movements and Host Species Transitions of Foot-and-Mouth Disease Virus Serotype SAT 2
Authors: Hall Matthew D. , Knowles Nick J. , Wadsworth Jemma , Rambaut Andrew , Woolhouse Mark E. J.
Published: October 2013

Of the three foot-and-mouth-disease virus SAT serotypes mainly confined to sub-Saharan Africa, SAT 2 is the strain most often recorded in domestic animals and has caused outbreaks in North Africa and the Middle East six times in the last 25 years, with three apparently separate events occurring in 2012. This study updates the picture of SAT 2 phylogenetics by using all available sequences for the VP1 section of the genome available at the time of writing and uses phylogeographic methods to trace the origin of all outbreaks occurring north of the Sahara since 1990 and identify patterns of spread among countries of endemicity. Transitions between different host species are also enumerated. Outbreaks in North Africa appear to have origins in countries immediately south of the Sahara, whereas those in the Middle East are more often from East Africa. The results of the analysis of spread within sub-Saharan Africa are consistent with it being driven by relatively short-distance movements of animals across national borders, and the analysis of host species transitions supports the role of the African buffalo (
Syncerus caffer
) as an important natural reservoir.

IMPORTANCE
Foot-and-mouth disease virus is a livestock pathogen of major economic importance, with seven distinct serotypes occurring globally. The SAT 2 serotype, endemic in sub-Saharan Africa, has caused a number of outbreaks in North Africa and the Middle East during the last decades, including three separate incidents in 2012. A comprehensive analysis of all available RNA sequences for SAT 2 has not been published for some years. In this work, we performed this analysis using all previously published sequences and 49 newly determined examples. We also used phylogenetic methods to infer the source country for all outbreaks occurring outside sub-Saharan Africa since 1990 and to reconstruct the spread of viral lineages between countries where it is endemic and movements between different host species.
Nerve afflictions of maxillofacial region: a report of two cases
Authors: Thada Smitha Rani , Gadda Rohit , Pai Keerthilatha
Published: October 2013

Neurological disorders and conditions affecting the maxillofacial region result in disabilities that affect an individual's functioning. Sensory or motor disturbances of the nerves may be caused by trauma, infections, pressure effect or infiltration by tumours or other health conditions. Two rare cases of nerve afflictions are described here with their typical clinical features. The first case had an involvement of maxillary, mandibular and ophthalmic divisions of the trigeminal nerve (sensory) due to herpes zoster infection in a very young patient and the second case had a unilateral isolated hypoglossal nerve palsy (motor) secondary to infiltration of the nerve by carcinoma of pyriform fossa.
‘Treatment of the Sportsman's groin’: British Hernia Society's 2014 position statement based on the Manchester Consensus Conference
Authors: Sheen Aali J , Stephenson B M , Lloyd D M , Robinson P , Fevre D , Paajanen H , de Beaux A , Kingsnorth A , Gilmore O J , Bennett D , Maclennan I , O'Dwyer P , Sanders D , Kurzer M
Published: October 2013

Introduction

The aim was to produce a multidisciplinary consensus to determine the current position on the nomenclature, definition, diagnosis, imaging modalities and management of Sportsman's groin (SG).

Methods

Experts in the diagnosis and management of SG were invited to participate in a consensus conference held by the British Hernia Society in Manchester, UK on 11–12 October 2012. Experts included a physiotherapist, a musculoskeletal radiologist and surgeons with a proven track record of expertise in this field. Presentations detailing scientific as well as outcome data from their own experiences were given. Records were made of the presentations with specific areas debated openly.

Results

The term ‘inguinal disruption’ (ID) was agreed as the preferred nomenclature with the term ‘Sportsman's hernia’ or ‘groin’ rejected, as no true hernia exists. There was an overwhelming agreement of opinion that there was abnormal tension in the groin, particularly around the inguinal ligament attachment. Other common findings included the possibility of external oblique disruption with consequent small tears noted as well as some oedema of the tissues. A multidisciplinary approach with tailored physiotherapy as the initial treatment was recommended with any surgery involving releasing the tension in the inguinal canal by various techniques and reinforcing it with a mesh or suture repair. A national registry should be developed for all athletes undergoing surgery.

Conclusions

ID is a common condition where no true hernia exists. It should be managed through a multidisciplinary approach to ensure consistent standards and outcomes are achieved.
Effect of drainage and sequential filling on the behavior of backfill in mine stopes
Authors: El Mkadmi Nawfal , Aubertin Michel , Li Li
Published: October 2013

Underground backfilling offers significant economic and environmental advantages to mining operations. There is however a limited knowledge and understanding of how the backfill behaves within mine stopes, which creates some concern regarding the risk of accidents with potentially serious consequences. It is thus important to investigate further the response of backfill to ensure safe working conditions and optimize the filling sequence. This paper presents key results from a numerical study aimed at analyzing the hydrogeotechnical response of backfill in a narrow vertical stope. The simulations illustrate how stresses are influenced by stope geometry, water drainage, and filling rate. Three main cases are presented here to illustrate these effects; namely, (i) simulation of dry (or drained) backfill, (ii) a rapidly filled stope with progressive drainage and consolidation, and (iii) sequential backfill placement with different filling rates. The third case includes a simulation with evolving properties due to the binder added to the backfill. The results from the numerical analyses show that arching effects develop within narrow backfilled stopes because of the stiffness contrast between the rock and the fill material. This can produce a significant reduction of the stresses (horizontal and vertical) in comparison with the overburden pressure. The simulation results also show the development of excess pore-water pressures after the placement of the saturated backfill within the stope. Drainage tends to reduce these pressures and increase the frictional stresses along the rock walls. The sequentially filled stope simulations show that a rapid filling rate produces much higher total stresses and excess pore-water pressures, compared to slower rates. The simulation of the cemented backfill, with evolving properties, indicates that the progressive changes can have a significant effect on the total and effective stresses in the stope. A discussion follows on the implications of these results.
The influence of regional gradients in climate and air pollution on epiphytes in riparian forest galleries of the upper Fraser River watershed
Authors: Coxson Darwyn , Björk Curtis , Bourassa Marie Danielle
Published: October 2013

Epiphyte diversity and abundance were examined along the Fraser River and its tributaries in central-interior British Columbia at varying distances from point-source air pollution discharges. Black cottonwood (Populus balsamifera L. ssp. trichocarpa (Torr. & A. Gray ex Hook.) Brayshaw trunks near discharges in Prince George had comparatively low epiphyte diversity and supported an unusual acidiphilic lichen community, including Tuckermannopsis chlorophylla (Willd.) Hale, Usnea lapponica Vain., and Vulpicida canadensis (Räsänen) J.-E. Mattsson & M.J. Lai. At a greater distance from air pollution sources, a more characteristic flora was observed, including Collema Wigg. spp., Lecidea erythrophaea Flörke, Leptogium (Ach.) Gray spp., Lobaria pulmonaria (L.) Hoffm., Nephroma parile (Ach.) Ach., Peltigera Willd. spp., and Strangospora moriformis (Ach.) Stein. These changes were accompanied by large differences in bark pH; mean values ranged from 3.7 in Prince George to 6.7 in upriver stands for black cottonwoods, from 3.5 to 5.4 for live spruce branches (Picea glauca (Moench) Voss), and from 3.1 to 4.9 for dead spruce branches, respectively. Epiphyte communities proximal to Prince George were characterized by many nitrophilous species. Our data showed a strong covariate influence of climate, with Lobarion community lichens more abundant in the easternmost high-precipitation plots. Numerous provincial- and global-level conservation priority species were found, including Collema quadrifidum D.F. Stone & McCune, newly discovered for Canada; Collema coniophilum Goward, a Species at Risk Act listed species; and provincially at risk Heterodermia speciosa (Wulf.) Trev., Physcia tribacia (Ach.) Nyl., and Santessoniella saximontana T. Sprib., P.M. Jørg. & M. Schultz, mostly in sites distant from air pollution sources.
A WIDEBAND CMOS CASCADED VARIABLE GAIN AMPLIFIER USING UNEQUALLY DISTRIBUTED GAIN CONTROL FOR DVB-S.2 RECEIVER
Authors: HWANG HYEONSEOK , KIM HOONKI , JEONG CHAN-HUI , KWON CHAN-KEUN , JEON SANGGEUN , KIM SOO-WON , NA YOOSAM , YOO HYUNHWAN
Published: October 2013

A fully integrated three stage cascaded radio frequency variable gain amplifier (RFVGA) linearly controlled by exponential current generation circuit is presented. The gain control is unequally distributed in each stage for noise figure (NF) and linearity performance. The dB-linear gain control is realized using pseudo exponential current generated by CMOS current summing circuit with a voltage to current converter. The RFVGA has over 50 dB dynamic range. Gain changes from -38.5 to 16.8 dB according to control voltage that varies from 0.5 to 1.8 V. It operates at 0.95–2.15 GHz. This design is implemented in 0.18 μm CMOS technology.
A PARITY AND A MULTI-VARIABLE POLYNOMIAL INVARIANT FOR VIRTUAL LINKS
Authors: IM YOUNG HO , PARK KYOUNG IL
Published: October 2013

We introduce a parity of classical crossings of virtual link diagrams which extends the Gaussian parity of virtual knot diagrams and the odd writhe of virtual links that extends that of virtual knots introduced by Kauffman [A self-linking invariants of virtual knots, Fund. Math.184 (2004) 135–158]. Also, we introduce a multi-variable polynomial invariant for virtual links by using the parity of classical crossings, which refines the index polynomial introduced in [Index polynomial invariants of virtual links, J. Knot Theory Ramifications19(5) (2010) 709–725]. As consequences, we give some properties of our invariant, and raise some examples.
HIP MORPHOLOGY: COMPARATIVE STUDY BETWEEN EGYPTIANS AND JAPANESE ADULTS
Authors: Aly Tarek , Fuji Genji
Published: October 2013

The prevalence of osteoarthritis appears to vary widely among ethinic groups. Many studies had been published describing the acetabular morphology of Chinese, Nigerians, Singaporeans and Japanese. No previous studies comparing Egyptian Arabs and Japanese Orientals work available. Purpose: The aim of this study was to determine the ethnic variations of acetabular morphology between Egyptian and Japanese populations. Patients and Methods: A total of 844 Egyptian and 757 Japanese consecutive patients with no clinical evidence of hip osteoarthritis and who underwent pelvic radiography in the supine position for hip trauma or a routine health check were analyzed for the relationships between the center-edge (CE) angle, Sharp angle, acetabular head index, as well as the relationships of the above-mentioned variables with age, gender, body height. Results: Comparing the measurements of those three parameters in both populations showed statistically significant values (all Egyptian versus Japanese, all female versus male are significant). Conclusion: Our data confirm the presence of ethnic variations in acetabular morphology which predispose to various pathologies of the hip joint.
AB INITIO HUMAN miRNA AND PRE-miRNA PREDICTION
Authors: TITOV IGOR I. , VOROZHEYKIN PAVEL S.
Published: October 2013

MicroRNAs (miRNAs) are small single-stranded noncoding RNAs that play an important role in post-transcriptional regulation of gene expression. In this paper, we present a web server for ab initio prediction of the human miRNAs and their precursors. The prediction methods are based on the hidden Markov Models and the context-structural characteristics. By taking into account the identified patterns of primary and secondary structures of the pre-miRNAs, a new HMM model is proposed and the existing context-structural Markov model is modified. The evaluation of the method performance has shown that it can accurately predict novel human miRNAs. Comparing with the existing methods we demonstrate that our method has a higher prediction quality both for human pre-miRNAs and miRNAs. The models have also showed good results in the prediction of the mouse miRNAs. The web server is available at http://wwwmgs.bionet.nsc.ru/mgs/programs/rnaanalys (mirror http://miRNA.at.nsu.ru ).