bluuebunny/crossref_metadata_2025 huggingface dataset:
Flight parameter estimation using time delay and intersensor multipath delay measurements from a small aperture acoustic array
Authors: Lo Kam W.
Published: July 2013

A ground-based acoustic sensor array can be used to estimate the complete set of flight parameters of a jet aircraft or other airborne source of broadband sound in transit by measuring the differential time of arrival (DTOA), or the time delay, of the direct path signal at each sensor pair of the array over a sufficiently long period of time. This paper studies the possibility of using intersensor multipath delay measurements to improve the precision of the flight parameter estimates for a small aperture array, without increasing the array's intersensor spacing or the observation time for more time delay measurements. Intersensor multipath delay is defined as the DTOA of the direct path signal at one sensor and the ground-reflected path signal at another sensor. The flight parameter estimation algorithm is formulated and a simplified Cramer-Rao lower bound error analysis is presented, which shows that the standard deviations in the flight parameter estimates are greatly reduced when intersensor multipath delay measurements are used together with time delay measurements. The effectiveness of the proposed flight parameter estimation method for small aperture arrays is verified using both simulated and real data.
Broadband synthetic aperture geoacoustic inversion
Authors: Tan Bien Aik , Gerstoft Peter , Yardim Caglar , Hodgkiss William S.
Published: July 2013

A typical geoacoustic inversion procedure involves powerful source transmissions received on a large-aperture receiver array. A more practical approach is to use a single moving source and/or receiver in a low signal to noise ratio (SNR) setting. This paper uses single-receiver, broadband, frequency coherent matched-field inversion and exploits coherently repeated transmissions to improve estimation of the geoacoustic parameters. The long observation time creates a synthetic aperture due to relative source-receiver motion. This approach is illustrated by studying the transmission of multiple linear frequency modulated (LFM) pulses which results in a multi-tonal comb spectrum that is Doppler sensitive. To correlate well with the measured field across a receiver trajectory and to incorporate transmission from a source trajectory, waveguide Doppler and normal mode theory is applied. The method is demonstrated with low SNR, 100–900 Hz LFM pulse data from the Shallow Water 2006 experiment.
The detection of repetitions in noise before and after perceptual learning
Authors: Agus Trevor R. , Pressnitzer Daniel
Published: July 2013

In noise repetition-detection tasks, listeners have to distinguish trials of continuously running noise from trials in which noise tokens are repeated in a cyclic manner. Recently, it has been shown that using the exact same noise token across several trials (“reference noise”) facilitates the detection of repetitions for this token [Agus et al. (2010). Neuron 66, 610–618]. This was attributed to perceptual learning. Here, the nature of the learning was investigated. In experiment 1, reference noise tokens were embedded in trials with or without cyclic presentation. Naïve listeners reported repetitions in both cases, thus responding to the reference noise even in the absence of an actual repetition. Experiment 2, with the same listeners, showed a similar pattern of results even after the design of the experiment was made explicit, ruling out a misunderstanding of the task. Finally, in experiment 3, listeners reported repetitions in trials containing the reference noise, even before ever hearing it presented cyclically. The results show that listeners were able to learn and recognize noise tokens in the absence of an immediate repetition. Moreover, the learning mandatorily interfered with listeners' ability to detect repetitions. It is concluded that salient perceptual changes accompany the learning of noise.
Measuring body layer vibration of vocal folds by high-frame-rate ultrasound synchronized with a modified electroglottograph
Authors: Tang Shanshan , Zhang Yuanyuan , Qin Xulei , Wang Supin , Wan Mingxi
Published: July 2013

The body-cover concept suggests that the vibration of body layer is an indispensable component of vocal fold vibration. To quantify this vibration, a synchronized system composed of a high-frame-rate ultrasound and a modified electroglottograph (EGG) was employed in this paper to simultaneously image the body layer vibration and record the vocal fold vibration phase information during natural phonations. After data acquisition, the displacements of in vivo body layer vibrations were measured from the ultrasonic radio frequency data, and the temporal reconstruction method was used to enhance the measurement accuracy. Results showed that the modified EGG, the waveform and characteristic points of which were identical to the conventional EGG, resolved the position conflict between the ultrasound transducer and EGG electrodes. The location and range of the vibrating body layer in the estimated displacement image were more clear and discernible than in the ultrasonic B-mode image. Quantitative analysis for vibration features of the body layer demonstrated that the body layer moved as a unit in the superior-inferior direction during the phonation of normal chest registers.
Identification and target strength of orange roughy (Hoplostethus atlanticus) measured in situ
Authors: Kloser Rudy J. , Macaulay Gavin J. , Ryan Tim E. , Lewis Mark
Published: July 2013

It is often assumed that in situ target strength (TS) measurements from dispersed fish are representative of the surveyed schooling fish. For in situ TS measurements of orange roughy in deep water, it has been difficult to validate the target species, individual lengths, and tilt angles and how representative these are of schooling fish. These problems have been addressed by attaching an acoustic optical system (AOS) to a trawl net. The AOS enables in situ measurements of TS and volume backscattering strength (Sv) at 38 and 120 kHz with optical verification of species and stereo camera measurements of fish length and tilt angle. TS estimates believed representative of the schooling population were derived by (1) weighting the frequency-dependent TS values by the Sv frequency difference distribution of orange roughy schools and (2) weighting the in situ TS measurements with an assumed tilt angle distribution. The 120-kHz TS estimates were less sensitive to variations in frequency difference and tilt angle, suggesting that this frequency may be better for biomass estimates than 38 kHz, the traditional survey frequency. Computations performed with an anatomically detailed scattering model agree with measurements of TS at both frequencies over a range of tilt angles.
Comment on “Short-term acoustic forecasting via artificial neural networks for neonatal intensive care units” [J. Acoust. Soc. Am. 132, 3234–3239 (2012)]
Authors: Park Munhum
Published: July 2013

In contrast to common expectations, the noise levels measured in hospital wards are known to be high with little day-night variation, potentially having negative effects on the patient outcomes and the work performance of the staff members, and considerable research attention has been drawn to such adverse acoustic conditions in healthcare environments. Recently, Young et al. [J. Acoust. Soc. Am. 132(5), 3234–3239 (2012)] proposed to use an artificial neural network (ANN) to predict the hourly energy-equivalent sound pressure level (Leq, 1h), particularly targeting neonatal intensive care units. Despite the timeliness of the study and the potential benefits of an “acoustic forecasting” model, the proposed scheme appears to be underdeveloped in a few important aspects, which this letter attempts to address. In particular, the prediction of a simpler time-series smoothing technique was equally or more accurate compared to that of the ANN. In addition, the percentage error used to indicate the prediction accuracy was not only perceptually irrelevant but also misleading given the narrow distribution of test data. Furthermore, this letter raises the more general question whether the sound pressure level may meaningfully be modeled solely based on the past time-series.
Psychoacoustical evaluation of natural and urban sounds in soundscapes
Authors: Yang Ming , Kang Jian
Published: July 2013

Among various sounds in the environment, natural sounds, such as water sounds and birdsongs, have proven to be highly preferred by humans, but the reasons for these preferences have not been thoroughly researched. This paper explores differences between various natural and urban environmental sounds from the viewpoint of objective measures, especially psychoacoustical parameters. The sound samples used in this study include the recordings of single sound source categories of water, wind, birdsongs, and urban sounds including street music, mechanical sounds, and traffic noise. The samples are analyzed with a number of existing psychoacoustical parameter algorithmic models. Based on hierarchical cluster and principal components analyses of the calculated results, a series of differences has been shown among different sound types in terms of key psychoacoustical parameters. While different sound categories cannot be identified using any single acoustical and psychoacoustical parameter, identification can be made with a group of parameters, as analyzed with artificial neural networks and discriminant functions in this paper. For artificial neural networks, correlations between network predictions and targets using the average and standard deviation data of psychoacoustical parameters as inputs are above 0.95 for the three natural sound categories and above 0.90 for the urban sound category. For sound identification/classification, key parameters are fluctuation strength, loudness, and sharpness.
Assessment of urban soundscapes with the focus on an architectural installation with musical features
Authors: Jambrošić Kristian , Horvat Marko , Domitrović Hrvoje
Published: July 2013

Urban soundscapes at five locations in the city of Zadar were perceptually assessed by on-site surveys and objectively evaluated based on monaural and binaural recordings. All locations were chosen so that they would display auditory and visual diversity as much as possible. The unique sound installation known as the Sea Organ was included as an atypical music-like environment. Typical objective parameters were calculated from the recordings related to the amount of acoustic energy, spectral properties of sound, the amount of fluctuations, and tonal properties. The subjective assessment was done on-site using a common survey for evaluating the properties of sound and visual environment. The results revealed the importance of introducing the context into soundscape research because objective parameters did not show significant correlation with responses obtained from interviewees. Excessive values of certain objective parameters could indicate that a sound environment will be perceived as unpleasant or annoying, but its overall perception depends on how well it agrees with people's expectations. This was clearly seen for the case of Sea Organ for which the highest values of objective parameters were obtained, but, at the same time, it was evaluated as the most positive sound environment in every aspect.
Narrow-band autocorrelation function features for the automatic recognition of acoustic environments
Authors: Valero Xavier , Alías Francesc
Published: July 2013

Acoustic environments are typically composed of multiple sound sources of different typologies, making them especially complex to model and parameterize. To develop an automatic acoustic environment recognition system, this work proposes a spectro-temporal signal parameterization technique inspired by human perception. The proposed parameters are derived from the analysis of the autocorrelation function of narrow-band signals (NB-ACF) obtained from an auditory gammatone filter bank. Five features related to acoustic phenomena are extracted from the NB-ACF to parameterize sound signals. Experiments are conducted on a 4 h sound database (composed of 15 different acoustic environments) employing four different machine learning techniques: K-nearest neighbor, Gaussian mixture models, neural networks and support vector machines. The averaged recognition rates increase by 4.5% when using the proposed NB-ACF features instead of the popular Mel frequency cepstral coefficients. The improvement is even greater (5.6%) when the features are tested in acoustic environments from unknown locations. These results are attributed to the better modeling of the acoustic environments thanks to the complementarity of the spectro-temporal features derived from NB-ACF analysis.
The ecological context of soundscapes for children's blood pressure
Authors: Lercher Peter , Evans Gary W. , Widmann Ulrich
Published: July 2013

Although the majority of studies on community noise levels and children's physiological stress responses are positive, effect sizes vary considerably, and some studies do not confirm these effects. Employing a contextual perspective congruent with soundscapes, a carefully constructed sample of children (N = 115, M = 10.1 yr) living in households in relatively high (>60 dBA) or low (<50 dBA) noise areas created by proximity to major traffic arterials in Austria was reanalyzed. Several personal and environmental factors known to affect resting cardiovascular parameters measured under well-controlled, clinical conditions were incorporated into the analyses. Children with premature births and elevated chronic stress (i.e., overnight cortisol) were more susceptible to adverse blood pressure responses to road traffic noise. Residence in a multi-dwelling unit as well as standardized assessments of perceived quietness of the area did not modify the traffic noise impacts but each had its own, independent effect on resting blood pressure. A primary air pollutant associated with traffic volume (NO2) had no influence on any of these results. The scope of environmental noise assessment and management would benefit from incorporation of a more contextualized approach as suggested by the soundscape perspective.
Application of a recently introduced index for acoustic complexity to an avian soundscape with traffic noise
Authors: Pieretti Nadia , Farina Almo
Published: July 2013

An altered acoustic environment can have severe consequences for natural communities, especially for species that use acoustic signals to communicate and achieve breeding success. Numerous studies have focused on traffic noise disturbance, but the possible causes of road effects are inter-correlated and the literature on noise qua noise is sometimes contradictory. To provide further empirical data in this regard, the authors investigated the spatio-temporal variability of the singing dynamics of an avian community living in an acoustic context altered by traffic noise. Fieldwork was carried out in a wood of Turkey oaks (central Italy) bordered on one side by a main road. The soundscape was examined by positioning eight digital recorders, distributed in two transects perpendicular to the road, and recording between 6:30 and 8.30 a.m. for 12 continuous sessions. The acoustic complexity index was used to obtain a quantification of singing dynamics, which were positively correlated with traffic noise. This may indicate that birds try to propagate their signals with greater emphasis (e.g., amplified redundancy or loudness of the songs) to override the masking effect of noise. Nevertheless, an ecotonal effect could have influenced the correlation results, with this enhanced dynamic possibly being due to a more densely populated environment.
Comments on “A theoretical model of the pressure field arising from asymmetric intraglottal flows applied to a two-mass model of the vocal folds” [J. Acoust. Soc. Am. 130, 389–403 (2011)]
Authors: Hirschberg Avraham
Published: July 2013

After demonstrating by means of an in vitro model experiment that the flow in the glottis can become asymmetric, Erath et al. [J. Acoust. Soc. Am. 130, 389–403 (2011)] propose a theory to estimate the resulting asymmetry in the lateral hydrodynamic force on the vocal folds. A wall-jet attached to one side of the divergent downstream part of the glottis is considered. The model assumes that the wall is a flat plate and that the jet separates at the glottal exit. They implement this so-called Boundary Layer Estimation of Asymmetric Pressure force model in a lumped two mass model of the vocal folds. This should allow them to study the impact of the asymmetry on voiced sound production. A critical discussion of the merits and shortcomings of the model is provided. It predicts discontinuities in the time dependency of the lateral force. It predicts this force to be independent from the glottal opening, which is not reasonable. An alternative model is proposed, which avoids these problems and predicts that there is a minimum glottal opening below which the wall-jet does not separate from the wall at the glottal exit. This is in agreement with the experimental results provided by Erath et al.
Sparse and structured decomposition of audio signals on hybrid dictionaries using musical priors
Authors: Papadopoulos Hélène , Kowalski Matthieu
Published: July 2013

This paper investigates the use of musical priors for sparse expansion of audio signals of music, on an overcomplete dual-resolution dictionary taken from the union of two orthonormal bases that can describe both transient and tonal components of a music audio signal. More specifically, chord and metrical structure information are used to build a structured model that takes into account dependencies between coefficients of the decomposition, both for the tonal and for the transient layer. The denoising task application is used to provide a proof of concept of the proposed musical priors. Several configurations of the model are analyzed. Evaluation on monophonic and complex polyphonic excerpts of real music signals shows that the proposed approach provides results whose quality measured by the signal-to-noise ratio is competitive with state-of-the-art approaches, and more coherent with the semantic content of the signal. A detailed analysis of the model in terms of sparsity and in terms of interpretability of the representation is also provided and shows that the model is capable of giving a relevant and legible representation of Western tonal music audio signals.
Perceptual constancy in auditory perception of distance to railway tracks
Authors: De Coensel Bert , Nilsson Mats E. , Berglund Birgitta , Brown A. L.
Published: July 2013

Distance to a sound source can be accurately estimated solely from auditory information. With a sound source such as a train that is passing by at a relatively large distance, the most important auditory information for the listener for estimating its distance consists of the intensity of the sound, spectral changes in the sound caused by air absorption, and the motion-induced rate of change of intensity. However, these cues are relative because prior information/experience of the sound source—its source power, its spectrum and the typical speed at which it moves—is required for such distance estimates. This paper describes two listening experiments that allow investigation of further prior contextual information taken into account by listeners—viz., whether they are indoors or outdoors. Asked to estimate the distance to the track of a railway, it is shown that listeners assessing sounds heard inside the dwelling based their distance estimates on the expected train passby sound level outdoors rather than on the passby sound level actually experienced indoors. This form of perceptual constancy may have consequences for the assessment of annoyance caused by railway noise.
Two parabolic equations for propagation in layered poro-elastic media
Authors: Metzler Adam M. , Siegmann William L. , Collins Michael D. , Collis Jon M.
Published: July 2013

Parabolic equation methods for fluid and elastic media are extended to layered poro-elastic media, including some shallow-water sediments. A previous parabolic equation solution for one model of range-independent poro-elastic media [Collins et al., J. Acoust. Soc. Am. 98, 1645–1656 (1995)] does not produce accurate solutions for environments with multiple poro-elastic layers. First, a dependent-variable formulation for parabolic equations used with elastic media is generalized to layered poro-elastic media. An improvement in accuracy is obtained using a second dependent-variable formulation that conserves dependent variables across interfaces between horizontally stratified layers. Furthermore, this formulation expresses conditions at interfaces using no depth derivatives higher than first order. This feature should aid in treating range dependence because convenient matching across interfaces is possible with discretized derivatives of first order in contrast to second order.
Comparative temporary threshold shifts in a harbor porpoise and harbor seal, and severe shift in a seal
Authors: Kastelein Ronald A. , Gransier Robin , Hoek Lean
Published: July 2013

Anthropogenic noise may cause temporary hearing threshold shifts (TTSs) in marine mammals. Tests with identical methods show that harbor porpoises are more susceptible to TTS induced by octave-band white noise (OBN) centered around 4 kHz than harbor seals, although their unmasked (basic) hearing thresholds for that frequency are similar. A harbor seal was exposed for 1 h to an OBN with a very high sound pressure level (SPL), 22–30 dB above levels causing TTS onset. This elicited 44 dB TTS; hearing recovered within 4 days. Thus, for this signal and this single exposure, permanent threshold shift requires levels at least 22 dB above TTS onset levels. The severe TTS in the seal suggests that the critical level (above which TTS increases rapidly with increasing SPL) is between 150 and 160 dB re 1 μPa for a 60 min exposure to OBN centered at 4 kHz. In guidelines on TTS in marine mammals produced by policy makers in many countries, TTS is assumed to follow the equal energy hypothesis, so that when the sound exposure levels of fatiguing sounds are equal, the same TTS is predicted to be induced. However, like previous studies, the present study calls this model into question.
Quantifying scattered sound energy from a single tree by means of reverberation time
Authors: Yang Hong-Seok , Kang Jian , Cheal Chris , Renterghem Timothy Van , Botteldooren Dick
Published: July 2013

Trees in urban spaces surrounded by buildings may be effective in dispersing sound energy, and this could affect sound level distribution and street canyon reverberation. To quantify this effect of trees with a view to including it in numerical predictions, this paper examines sound scattering from a single tree in open field by means of reverberation time (RT). Five trees of different species and crown sizes were considered. The influence of ground condition, receiver height, crown size and shape, foliage condition, and source-receiver angle and distance has been assessed. The results show that RT20 is proportional to the tree crown size, which is the most important factor. The maximum RT20 measured was 0.28 s at 4000 Hz for the studied trees when in leaf (with foliage). The presence of leaves increased RT20 at high frequencies, typically by 0.08 s at 4000 Hz. It was also demonstrated that the source-receiver angle can affect the characteristics of decay curves significantly. With increasing source-receiver distance within 40 m, RT20 was slightly changed. It was shown that ground condition and receiver height affect the decay curves, especially at low and mid frequencies, where sound scattering is of relatively limited importance.
Impulse source versus dodecahedral loudspeaker for measuring parameters derived from the impulse response in room acoustics
Authors: San Martín Ricardo , Arana Miguel , Machín Jorge , Arregui Abel
Published: July 2013

This study investigates the performance of dodecahedral and impulse sources when measuring acoustic parameters in enclosures according to ISO 3382-1 [Acoustics–Measurement of room acoustic parameters. Part 1: Performance spaces (International Organization for Standardization, Geneva, Switzerland, 2009)]. In general, methods using speakers as a sound source are limited by their frequency response and directivity. On the other hand, getting impulse responses from impulse sources typically involves a lack of repeatability, and it is usually necessary to average several measurements for each position. Through experiments in different auditoriums that recreate typical situations in which the measurement standard is applied, it is found that using impulse sources leads to greater variation in the results, especially at low frequencies. However, this prevents subsequent dispersions due to variables that this technique does not require, such as the orientation of the emitting source. These dispersions may be relevant at high frequencies exceeding the established tolerance criteria for certain parameters. Finally, a new descriptor for dodecahedral sources reflecting the influence their lack of omnidirectionality produces on measuring acoustic parameters is proposed.
Misperceptions of spoken words: Data from a random sample of American English words
Authors: Albert Felty Robert , Buchwald Adam , Gruenenfelder Thomas M. , Pisoni David B.
Published: July 2013

This study reports a detailed analysis of incorrect responses from an open-set spoken word recognition experiment of 1428 words designed to be a random sample of the entire American English lexicon. The stimuli were presented in six-talker babble to 192 young, normal-hearing listeners at three signal-to-noise ratios (0, +5, and +10 dB). The results revealed several patterns: (1) errors tended to have a higher frequency of occurrence than did the corresponding target word, and frequency of occurrence of error responses was significantly correlated with target frequency of occurrence; (2) incorrect responses were close to the target words in terms of number of phonemes and syllables but had a mean edit distance of 3; (3) for syllables, substitutions were much more frequent than either deletions or additions; for phonemes, deletions were slightly more frequent than substitutions; both were more frequent than additions; and (4) for errors involving just a single segment, substitutions were more frequent than either deletions or additions. The raw data are being made available to other researchers as supplementary material to form the beginnings of a database of speech errors collected under controlled laboratory conditions.
Time-selective windowing technique in free-field microphone reciprocity calibration
Authors: Kwon Hyu-Sang , Cho Wan-Ho , Suh Sang-Joon
Published: July 2013

Time-selective windowing techniques, which effectively remove multi-path noise, have been widely utilized for reciprocity calibration of microphone there are still limitations imposed by overlapping signals, particularly at low frequencies and for high Q microphones. Based on a fast Fourier transform analysis, the leakage due to a limited frequency range makes the overlap problem worse, not be perfectly separated. Instead of using conventional low-pass filters that are designed to have a flat response in the frequency range of interest, in this study, a filter with a Dolph–Chebyshev window shape was proposed because it has low sidelobe levels. After removing multi-path noise with a time-selective window, an inverse filter should be applied to compensate for distortion created by the applied filter. The method suggested in this paper extends the possible frequency range of free-field reciprocity calibration to frequencies below 2 kHz.
Empirical and quadrature approximation of acoustic field and array response probability density functions
Authors: Hayward Thomas J. , Oba Roger M.
Published: July 2013

Numerical methods are presented for approximating the probability density functions (pdf's) of acoustic fields and receiver-array responses induced by a given joint pdf of a set of acoustic environmental parameters. An approximation to the characteristic function of the random acoustic field (the inverse Fourier transform of the field pdf) is first obtained either by construction of the empirical characteristic function (ECF) from a random sample of the acoustic parameters, or by application of generalized Gaussian quadrature to approximate the integral defining the characteristic function. The Fourier transform is then applied to obtain an approximation of the pdf by a continuous function of the field variables. Application of both the ECF and generalized Gaussian quadrature is demonstrated in an example of a shallow-water ocean waveguide with two-dimensional uncertainty of sound speed and attenuation coefficient in the ocean bottom. Both approximations lead to a smoother estimate of the field pdf than that provided by a histogram, with generalized Gaussian quadrature providing a smoother estimate at the tails of the pdf. Potential applications to acoustic system performance quantification and to nonparametric acoustic signal processing are discussed.
Shear wave speed dispersion and attenuation in granular marine sediments
Authors: Kimura Masao
Published: July 2013

The reported compressional wave speed dispersion and attenuation could be explained by a modified gap stiffness model incorporated into the Biot model (the BIMGS model). In contrast, shear wave speed dispersion and attenuation have not been investigated in detail. No measurements of shear wave speed dispersion have been reported, and only Brunson's data provide the frequency characteristics of shear wave attenuation. In this study, Brunson's attenuation measurements are compared to predictions using the Biot–Stoll model and the BIMGS model. It is shown that the BIMGS model accurately predicts the frequency dependence of shear wave attenuation. Then, the shear wave speed dispersion and attenuation in water-saturated silica sand are measured in the frequency range of 4–20 kHz. The vertical stress applied to the sample is 17.6 kPa. The temperature of the sample is set to be 5 °C, 20 °C, and 35 °C in order to change the relaxation frequency in the BIMGS model. The measured results are compared with those calculated using the Biot–Stoll model and the BIMGS model. It is shown that the shear wave speed dispersion and attenuation are predicted accurately by using the BIMGS model.
Characteristics of sound propagation in shallow water over an elastic seabed with a thin cap-rock layer
Authors: Duncan Alec J. , Gavrilov Alexander N. , McCauley Robert D. , Parnum Iain M. , Collis Jon M.
Published: July 2013

Measurements of low-frequency sound propagation over the areas of the Australian continental shelf, where the bottom sediments consist primarily of calcarenite, have revealed that acoustic transmission losses are generally much higher than those observed over other continental shelves and remain relatively low only in a few narrow frequency bands. This paper considers this phenomenon and provides a physical interpretation in terms of normal modes in shallow water over a layered elastic seabed with a shear wave speed comparable to but lower than the water-column sound speed. A theoretical analysis and numerical modeling show that, in such environments, low attenuation of underwater sound is expected only in narrow frequency bands just above the modal critical frequencies which in turn are governed primarily by the water depth and compressional wave speed in the seabed. In addition, the effect of a thin layer of harder cap-rock overlaying less consolidated sediments is considered. Low-frequency transmission loss data collected from an offshore seismic survey in Bass Strait on the southern Australian continental shelf are analyzed and shown to be in broad agreement with the numerical predictions based on the theoretical analysis and modeling using an elastic parabolic equation solution for range-dependent bathymetry.
Influence of preparation time and pitch separation in switching of auditory attention between streams
Authors: Larson Eric , Lee Adrian K. C.
Published: July 2013

The ability to consciously switch attention between speakers of interest is necessary for communication in many environments, especially when multiple talkers speak simultaneously. Segregating sounds of interest from the background, which is necessary for selective attention, depends on stimulus acoustics such as differences in spectrotemporal properties of the target and masker. However, the relationship between top-down attention control and bottom-up stimulus segregation is not well understood. Here, two experiments were conducted to examine the time necessary for listeners to switch auditory attention, and how the ability to switch attention relates to the pitch separation cue available for bottom-up stream segregation.
Acoustic mode coupling due to subaqueous sand dunes in the South China Sea
Authors: Chiu Linus Y. S. , Reeder D. Benjamin
Published: July 2013

The large subaqueous sand dunes on the upper continental slope of the South China Sea are expected to couple acoustic propagating normal modes. In this letter, the criterion of adiabatic invariance is extended to the case of a waveguide possessing bedforms. Using the extended criterion to examine mode propagation over the bedforms observed in the sand dune field in 2012, results demonstrate that bedforms increase mode coupling strength such that the criterion for adiabatic propagation is exceeded for waveguides with small bedform amplitude to water depth ratios; increasing bedform amplitude enhances mode coupling. Numerical simulations confirm the extended criterion parameterization.
Injection-Induced Earthquakes
Authors: Ellsworth William L.
Published: July 2013

Movers and Shakers

We tend to view earthquakes as unpredictable phenomena caused by naturally shifting stresses in Earth's crust. In reality, however, a range of human activity can also induce earthquakes.
Ellsworth
(p.
10.1126/science.1225942
) reviews the current understanding of the causes and mechanics of earthquakes caused by human activity and the means to decrease their associated risk. Notable examples include injection of wastewater into deep formations and emerging technologies related to oil and gas recovery, including hydraulic fracturing. In addition to directly causing increased local seismic activity, activities such as deep fluid injection may have other ramifications related to earthquake occurrence.

Van der Elst
et al.

(p.
164
; see the news story by

Kerr

) demonstrate that in the midwestern United States, some areas with increased human-induced seismicity are also more prone to further earthquakes triggered by the seismic waves from large, remote earthquakes. Improved seismic monitoring and injection data near deep disposal sites will help to identify regions prone to remote triggering and, more broadly, suggest times when activities should, at least temporarily, be put on hold.
Mg
2+
Regulates Cytotoxic Functions of NK and CD8 T Cells in Chronic EBV Infection Through NKG2D
Authors: Chaigne-Delalande Benjamin , Li Feng-Yen , O’Connor Geraldine M. , Lukacs Marshall J. , Jiang Ping , Zheng Lixin , Shatzer Amber , Biancalana Matthew , Pittaluga Stefania , Matthews Helen F. , Jancel Timothy J. , Bleesing Jack J. , Marsh Rebecca A. , Kuijpers Taco W. , Nichols Kim E. , Lucas Carrie L. , Nagpal Sunil , Mehmet Huseyin , Su Helen C. , Cohen Jeffrey I. , Uzel Gulbu , Lenardo Michael J.
Published: July 2013

Magnesium to the Rescue

Individuals with X-linked immunodeficiency with Mg
2+
defect, Epstein-Barr virus (EBV) infection, and neoplasia (XMEN) disease are genetically deficient for expression of
MAGT1
, a magnesium transporter.

Chaigne-Delalande
et al.

(p.
186
) sought to better understand why these individuals are chronically infected with EBV at high viral loads and are susceptible to the development of lymphomas. CD8
+
T cells and natural killer cells, which help to keep EBV infection in check, exhibited reduced cytotoxicity owing to their lower expression of the cell surface receptor NKG2D, which triggers cytolysis upon ligation. Magnesium supplementation in vitro and also in two XMEN patients restored levels of free Mg
2+
, increased NKG2D expression, and resulted in reduced amounts of EBV
+
cells, suggesting that this may be an effective therapeutic approach for XMEN patients.
Tuning Molecular Solids
Authors: Batail Patrick
Published: July 2013

Molecular clusters and fullerenes form ordered structures with potentially tunable properties.

[Also see Report by

Roy
et al.

]
Origins of the Modern Prometheus
The Lady and Her Monsters
A Tale of Dissections, Real-Life Dr. Frankensteins, and the Creation of Mary Shelley's Masterpiece

by Roseanne Montillo

William Morrow (HarperCollins), New York, 2013. 332 pp. $26.99, £17.30. ISBN 9780062025814.
Authors: Goldman Michael A.
Published: July 2013

Montillo's biography of Mary Shelley sketches the social and scientific contexts that shaped the origin of
Frankenstein
.
Nature's Other Self-Assemblers
Authors: Bentley William E. , Payne Gregory F.
Published: July 2013

Materials based on phenolics may provide another natural route to fabricating exotic structures with advanced functionality.

[Also see Report by

Ejima
et al.

]
Some Earthquakes Warn That They Are About to Strike
Authors: Kerr Richard A.
Published: July 2013

For some earthquakes induced by deep wastewater injection, a warning comes before they hit.
As Budgets Tighten, Washington Talks of Shaking Up DOE Labs
Authors: Malakoff David
Published: July 2013

There's talk in Washington of a new effort to shake up how the Department of Energy manages its sprawling network of 17 national laboratories.
Diverse Crystals Account for Beetle Sheen
Authors: Pennisi Elizabeth
Published: July 2013

Researchers have now traced the evolutionary history of iridescence in one group of beetles, the weevils, and identified an unexpectedly varied assortment of complex light-altering crystals in the insects.
JET Fusion Reactor Passes 30 and Plunges Into Midlife Crisis
Authors: Clery Daniel
Published: July 2013

The world's largest fusion reactor, the 30-year-old Joint European Torus, may close in 2018 unless the cash-strapped European Union can persuade partners in other parts of the world to help keep it running.
A Combined Disk Test for Direct Differentiation of Carbapenemase-Producing Enterobacteriaceae in Surveillance Rectal Swabs
Authors: Pournaras Spyros , Zarkotou Olympia , Poulou Aggeliki , Kristo Ioulia , Vrioni Georgia , Themeli-Digalaki Katerina , Tsakris Athanassios
Published: July 2013

Carbapenemase-producing
Enterobacteriaceae
(CPE) are rapidly spreading worldwide. Early detection of fecal CPE carriers is essential for effective infection control. Here, we evaluated the performance of a meropenem combined disk test (CDT) for rapidly differentiating CPE isolates directly from rectal swabs. The screening method was applied for 189 rectal swabs from hospitalized patients at high risk for CPE carriage. Swabs were suspended in 1 ml saline and cultured for confluent growth onto a MacConkey agar plate with a meropenem (MER) disk alone, a MER disk plus phenyl boronic acid (PBA), a MER disk plus EDTA, and a MER disk plus PBA and EDTA. An inhibition zone of ≤25 mm around the MER disk alone indicated carriage of carbapenem-resistant organisms. Furthermore, ≥5-mm differences in the inhibition zone between MER disks without and with the inhibitors (PBA, EDTA, or both) were considered positive results for detecting
Klebsiella pneumoniae
carbapenemase (KPC), metallo-β-lactamase (MBL), or both carbapenemases, respectively. For comparison, rectal suspensions were tested using MacConkey plates with ertapenem (MacERT) disks and PCR (PCR-S) for carbapenemase genes. Of the 189 samples, 97 were genotypically confirmed as CPE positive by one of the three protocols tested. The CDT, MacERT disks, and PCR-S assays exhibited sensitivities of 94.8%, 96.9%, and 94.8% and specificities of 100%, 98.9%, and 100%, respectively, for detecting CPE-positive swabs. Moreover, the CDT correctly differentiated the production of KPC, MBL, or both carbapenemases in 78 of the 97 (80.4%) CPE-positive rectal swabs. Our results demonstrate that the CDT may provide a simple and inexpensive method for detecting and differentiating the carbapenemase type within a single day without requiring further testing and additional delay, supporting the timely implementation of infection control measures.
Hsp90 Inhibitor 17-DMAG Decreases Expression of Conserved Herpesvirus Protein Kinases and Reduces Virus Production in Epstein-Barr Virus-Infected Cells
Authors: Sun Xiaoping , Bristol Jillian A. , Iwahori Satoko , Hagemeier Stacy R. , Meng Qiao , Barlow Elizabeth A. , Fingeroth Joyce D. , Tarakanova Vera L. , Kalejta Robert F. , Kenney Shannon C.
Published: July 2013

All eight human herpesviruses have a conserved herpesvirus protein kinase (CHPK) that is important for the lytic phase of the viral life cycle. In this study, we show that heat shock protein 90 (Hsp90) interacts directly with each of the eight CHPKs, and we demonstrate that an Hsp90 inhibitor drug, 17-dimethylaminoethylamino-17-demethoxygeldanamycin (17-DMAG), decreases expression of all eight CHPKs in transfected HeLa cells. 17-DMAG also decreases expression the of the endogenous Epstein-Barr virus protein kinase (EBV PK, encoded by the BGLF4 gene) in lytically infected EBV-positive cells and inhibits phosphorylation of several different known EBV PK target proteins. Furthermore, 17-DMAG treatment abrogates expression of the human cytomegalovirus (HCMV) kinase UL97 in HCMV-infected human fibroblasts. Importantly, 17-DMAG treatment decreased the EBV titer approximately 100-fold in lytically infected AGS-Akata cells without causing significant cellular toxicity during the same time frame. Increased EBV PK expression in 17-DMAG-treated AGS-Akata cells did not restore EBV titers, suggesting that 17-DMAG simultaneously targets multiple viral and/or cellular proteins required for efficient viral replication. These results suggest that Hsp90 inhibitors, including 17-DMAG, may be a promising group of drugs that could have profound antiviral effects on herpesviruses.
‘Golden Kernels within the skin’: disseminated cutaneous gout
Authors: Lo Tom Edward Ngo , Racaza Geraldine Zamora , Penserga Ester Gonzales
Published: July 2013

Presented in this paper is a case of a young Filipino man presenting with recurrent acute gouty flares leading to chronic tophaceous gout and unusual cutaneous manifestations (miliary gout, panniculitis, ulcerations). Unusual sites within the body (torso, shoulder, forearms, thigh) revealed multiple urate dermal deposition. Self-medication with steroids eventually led to secondary Cushing's syndrome and eventual emergence of metabolic complications.
Not your usual diarrhoea: severe colonic toxicity of mycophenolate due to intestinal CMV and EBV infection
Authors: Seifert Heike , Hess Christoph , Terracciano Luici , Eckstein Jens
Published: July 2013

We report a case of a 52-year-old woman, on immunosuppressive treatment with mycophenolate due to a history of giant cell myocarditis (GCM), who presented with new-onset severe blood-tinged diarrhoea after a cytomegalovirus (CMV) primoinfection. An extensively prolonged mycophenolate-related colitis was seen after withdrawal of mycophenolate due to an intestinal Epstein-Barr virus (EBV) infection—a rarely seen event itself. We postulate that colonic toxicity was triggered by CMV infection and perpetuated by intestinal EBV replication/infection.
Neonatal prolapsed patent vitellointestinal duct
Authors: Patel Ramnik V , Kumar Hemant , Sinha C K , Patricolo Mario
Published: July 2013

A case of a prolapsed patent vitellointestinal duct (PVID) in a 10-day-old neonate who presented with vomiting and poor weight gain with partial intestinal obstruction and a flower like pink, prolapsing lesion at his umbilicus has been reported. A limited contrast study through the tubular structure confirmed it to be a PVID. He underwent transumbilical exploration and resection and anastomosis uneventfully. Persistence of the vitellointestinal duct as a whole or part of it leads to a wide variety of anomalies–Meckel's diverticulum is the commonest lesion and a PVID is the rarest. Umbilical cord clamping flush with the abdominal wall may convert a Meckel's diverticulum prolapsing in the base of umbilical ring into a PVID. Careful assessment should be made for associated anomalies. Transumbilical exploration gives the best cosmetic and functional results.
Tuberculosis verrucosa cutis in a patient with keloid over ear lobule
Authors: Halim Muhammad Sohail , Ahmed Sadaf Qadeer , Junaid Montasir , Bashir Muhammad Rizwan
Published: July 2013

Tuberculosis (TB) is a global health problem with predominance in resource-poor countries. Extrapulmonary TB constitutes approximately 10% of the cases and can present as different forms depending on the route of entry. Cutaneous TB is a small subset of the extrapulmonary TB. Cutaneous TB can either be of primary origin or secondary origin or it can be a part of a systemic infection. TB verrucosa cutis (TBVC) is the exogenous reinfection of TB in a previously sensitised patient. Routine cultures do not have a high yield in TBVC due to the paucibacillary nature of the organism. Here we are presenting a rare case of a patient who developed in a keloid over the right ear lobule following ear piercing. This has only been presented once in the previous literature and for the first time in the head and neck region.
Allogenous tooth fragment reattachment
Authors: Maitin Nitin , Maitin Shipra , Rastogi Khushboo , Bhushan Rajarshi
Published: July 2013

Coronal fractures of the anterior teeth are a common form of dental trauma and its sequelae may impair the establishment and accomplishment of an adequate treatment plan. Among the various treatment options, reattachment of a crown fragment obtained from a previously extracted tooth is a conservative treatment that should be considered for crown fractures of anterior teeth. This article reports reattachment of an allogenous tooth fragment in a fractured maxillary lateral incisor in a 38-year-old patient. It is suggested that allogenous reattachment in a fractured anterior tooth serves to be a better alternative and should be further researched. Aesthetic and functional rehabilitation of a fractured complicated anterior crown using allogenous tooth fragment is a better alternative to other more conventional treatment options.
Snowboard, wakeboard, dashboard? Isolated fracture of the lateral process of the talus in a high-speed road traffic accident
Authors: Ng Evangeline Shimei , O'Neill Barry James , Cunningham Laurence Patrick , Quinlan John Francis
Published: July 2013

We present a 23-year-old man who sustained an isolated fracture of the lateral process of the talus (LPT) in a head-on vehicle collision at a combined speed of 200 km/h. The driver of the other vehicle sustained fatal injuries at the scene. The LPT was openly reduced and fixed with successful outcome at 3 months. This case is unusual in the method of injury, in particular in relation to the isolated relatively minor injury sustained.