bluuebunny/crossref_metadata_2025 huggingface dataset:
Implications of shallow water propagation for ranging by marine mammals
Authors: Mercado Eduardo , Schneider Jennifer N. , Green Sean R. , Rubin Rachael D.
Published: October 2013

Marine mammals rely heavily on acoustic communication to locate one another in low-visibility underwater environments. How these animals localize sounds sources is poorly understood. The speed of sound, attenuation, and reverberation in shallow water environments differ from those in terrestrial environments such that intensity cues alone may not be sufficient for ranging. The purpose of this study was to examine sound propagation in shallow, coastal waters near Rincon, Puerto Rico, and to determine what acoustic cues provide consistent information about source distance. Narrow-band tones and broadband sounds of similar frequency content (100–22000 Hz) and duration (2.0 s) to sound units of humpback whale song were broadcast from an underwater speaker. Sounds were recorded at known distances ranging from 70–850 m from the sound source. The received intensity was negatively correlated with distance propagated; broadband sounds showed a stronger correlation than narrow-band sounds. Analysis of the intensity-normalized spectral content of received sounds revealed a complex pattern of sound degradation: the distribution of peaks and notches within the frequency band alternating systematically as a function of distance. These results indicate that intensity cues to source distance are frequency dependent and that marine mammals may use cues other than intensity when ranging. [This work was supported in part by the Earthwatch Foundation and the UB Honors Program.]
Neural correlates of auditory streaming with unresolved harmonics
Authors: Yasin Ifat , Plack Christopher
Published: October 2013

The magnetoencephalographic negative wave N1m may be used as an indicator of auditory stream segregation [Gutschalk et al., J. Neurosci. 25, 5382–5388 (2005)]. When a repeating sequence of a pure-tone triplet (ABA-) is perceived as a single stream, the N1m amplitude is relatively small and consistent with the inter-stimulus-interval (ISI) between successive tones. When the sequence is perceived as segregated, the N1m amplitude is relatively large and consistent with the longer ISI between tones of each segregated stream. The present study used the electroencephalographic equivalent, wave N1, to investigate stream segregation based solely on temporal cues. Each triplet was comprised of complex tones with an f0=62.5, with unresolved harmonics summed either in sine phase, or in alternating sine-cosine phase, with a pitch corresponding to f0 and 2* f0, respectively. The effect of disrupting segregation was investigated by introducing increasing amounts of temporal jitter imposed by reducing the ISI for a complex within a triplet. Initial analyses tend to suggest that N1 amplitude is increased if the conditions for segregation are appropriate (when presentation rate is increased). Furthermore, N1 amplitude decreases as the amount of jitter increases, consistent with a disruption of segregation. [Work supported by ESRC and MRC.]
What’s wrong with these formants?
Authors: Fulop Sean A.
Published: October 2013

Speech is frequently modeled as an all-pole (autoregressive) linear filter applied to a voice source, commonly called Linear Predictive Coding. This model has been used for many years to provide measurements of the resonance frequencies (formants) characterizing speech sounds. That notwithstanding, it has also been well recognized that the use of this method to measure formants is very often fraught with problems, but just how serious are these problems, and can anything be done to improve upon LPC formant measurements? A few examples will demonstrate that the problems plaguing LPC formant measurements are too often intractable, and frequently yield formant values which are nowhere near the truth. For example, the voice bar will be shown to falsely lower the reported first formant value in many simple cases. It might even be suggested that reliance on this technique has impeded our understanding of exotic speech sounds which do not display a typical formant pattern. Precision formant measurements can be provided in most instances by reassigned spectrograms that have been specially processed to highlight signal components. Examples will be shown and used as benchmarks against which the LPC method can at last be properly evaluated.
Pulse-compression ultrasound imaging using a 40-MHz annular array
Authors: Mamou Jonathan , Ketterling Jeffrey A.
Published: October 2013

High-frequency ultrasound allows fine-resolution imaging at the expense of limited depth-of-field and acoustic penetration depth. Coded-excitation imaging allows a significant increase in the signal-to-noise ratio (SNR) and acoustic penetration depth. A 40-MHz, five-element annular array with a focal length of 12 mm and a total aperture of 6 mm was made using a 9-μm thick PVDF-TrFe membrane. The transducer was excited with an optimized, custom design, 4-μs, linear chirp spanning 15 to 65 MHz that was deduced from ex vivo experiments and computer simulations. Images of a 12-μm wire were generated to quantify lateral and axial resolutions. All 25 transmit/receive signal combinations were digitized and post-processed for compression and synthetic focusing. Compression consisted of linearly filtering the signals with the time-reversed excitation chirp modulated by a Dolph-Chebyshev window. Results showed that resolutions were not significantly degraded when compared to a conventional monocycle excitation and that SNR was improved by more than 14 dB. Images of mouse embryos showed marked improvements in image-quality. [Work supported in part by NIH Grant R21 EB006509.]
Troubleshooting the Vivian Beaumont Theatre
Authors: Jaffe J. Christopher , Cooper Russell
Published: October 2013

Troubleshooting room acoustics can vary from the sublime to the ridiculous. This paper discusses some simple solutions to problems related to a lack of knowledge of basic acoustic characteristics. However, the main example in the paper relates to modifications made to the Vivian Beaumont Theatre at Lincoln Center over a period of many years. The Beaumont is a 1500-seat thrust theatre designed in the 1960s to house the Lincoln Center Repertory Company. Since opening night the theatre was plagued with poor speech intelligibility based on the facts that the seating capacity is too large for the thrust format and that the designers placed an immense proscenium stage house behind the thrust. The acoustic solutions implemented were based on discussions with two different managing directors, Joseph Pape and Bernard Gersten, and their different visions on how to mount productions in the space.
Calibration of source level, expected transmitted power, and reverberation for long-range sonar in fluctuating range-dependent ocean waveguides
Authors: Ratilal Purnima , Andrews Mark , Galinde Ameya , Makris Nicholas
Published: October 2013

The ocean waveguide is temporally and spatially varying. An acoustic signal transmitted through the ocean or scattered from objects will get randomized. Estimating parameters of sonar, the environment, and scatterers requires a statistical approach that incorporates medium uncertainties into the signal analysis. Here we discuss source level, transmission loss (TL), and reverberation model calibration using data acquired with a long-range sonar on the New Jersey STRATAFORM. Broadband acoustic data measured by a desensitized hydrophone in a towed horizontal receiving array at numerous locations from a vertical source array are analyzed. The match-filtered data are compared to the expected TL output from a parabolic equation model that accounts for bathymetric variations. A maximum likelihood estimator is implemented to provide a global inversion of the data for source level, attenuation due to scattering, and match-filter degradation in the multi-modal ocean waveguide. An estimate is also provided of the coherence bandwidth for broadband acoustic signal transmission in this environment. A challenge in calibrating bottom reverberation models with sonar data lies in separating the scattered intensity from moving objects, such as fish groups, and distinguishing them from the statistically stationary background reverberation. An approach is presented for this purpose.
The causal impulse response for circular pistons in viscous media
Authors: Kelly James F. , McGough Robert J.
Published: October 2013

A causal impulse response for the Stokes wave equation is derived for calculations of transient pressure fields generated by circular pistons in viscous media. The causal Green’s function is numerically verified using the material impulse response function approach. The causal, lossy impulse response for a baffled circular piston is then calculated within the near-field and the far-field regions using expressions previously derived for the fast near-field method. Expressions for apodized pistons evaluated in the far-field region are also demonstrated. Transient pressure fields in viscous media are computed with the causal, lossy impulse response and compared to results obtained with the lossless impulse response. The numerical error in the computed pressure field is quantitatively analyzed for a range of viscous relaxation times and piston radii. Results show that the largest errors are generated in locations near the piston face and for large relaxation times, and errors are relatively small otherwise. These results suggest that this causal impulse response is ideal for time-domain calculations that simultaneously account for diffraction and frequency-dependent attenuation in viscous media. [This work was partially supported by NIH Grant 1R01 CA093669.]
The relation between lung damage induced by acoustic excitation and the subharmonic response of bubbles
Authors: Young Jonathan , Gracewski Sheryl M. , McAleavy Stephen , Dalecki Diane
Published: October 2013

Edwin L. Carstensen has made significant contributions to determining thresholds for and understanding mechanisms of mammalian lung hemorrhage caused by both ultrasound and lithotripter shock waves. The work presented here extends this knowledge base to investigate mechanisms of lung damage caused by acoustic excitation at the lung resonance frequency. This situation is relevant to divers exposed to high-amplitude, low-frequency sonar. Based on preliminary experiments, it was hypothesized that the threshold for lung hemorrhage at resonance occurs when lung surface oscillations at the subharmonic frequency of order one-half become unstable, producing significantly larger lung displacements. A balloon model was developed to approximate the behavior of small mammalian lung. The theoretical model for surface mode oscillations of a bubble was modified to account for the initial tension in the balloon membrane and used to investigate the stability of subharmonic oscillations. Reasonable agreement between the theoretical model and experimental measurements of the balloon surface displacements were obtained. In addition, a sharp pressure threshold for the presence of subharmonic oscillations was observed in the displacement data for the balloon model. The relevance of these simulations and measurements to murine lung hemorrhage will be discussed.
Measuring bubble dynamics in lithotripsy using a high-speed camera
Authors: Chitnis Parag V. , Cleveland Robin O.
Published: October 2013

The primary goal of this study was to examine bubble dynamics in shock wave lithotripsy and experimentally obtain the radius-time (r-t) profile. A piezoelectric array was employed as a shock wave (SW) source. The focal waveform (as measured with a fiber optic probe hydrophone) was double-peaked with two shocks: leading peak pressure 65±3 MPa and second peak 30±3 MPa. The negative phase in between had a peak p−=−16±2 MPa. The cavitation field was monitored using a dual passive cavitation detector consisting of two 1-MHz focused transducers. The second peak of the SW inhibited cavitation limiting the characteristic time to less than 60 μs. A high-speed camera (up to 10 million frames per second) with a spatial resolution of 2 μm/pixel was used to measure bubble dynamics. The camera could record 14 frames that were timed to measure the growth and collapse phases of the bubbles. The bubbles were initially spherical but became aspherical and exhibited jetting as they collapsed. The bubble radius was estimated from the area of bubble in each snapshot from which r-t curves were constructed and compared to calculations using the Gilmore formulation. The maximum radius ranged from 150 to 300 μm. [Work supported by NIH.]
Revisiting psychometric functions for frequency discrimination
Authors: Dai Huanping
Published: October 2013

In studies of auditory detection and discrimination, psychometric functions not only describe listeners sensitivity to changes in the stimulus, but often provide information regarding the auditory neural coding mechanisms involved in these tasks. In the present study, psychometric functions for frequency discrimination were systematically measured with a group of normal-hearing young adults. Frequency difference limens were in agreement with previous reports in their dependence on frequency. On the other hand, unlike that implied in previous analyses, the slopes of the psychometric functions, expressed in log(d) versus log(ΔF), were found to be consistently shallower than unity at frequencies below 4 kHz. Only at higher frequencies did the slopes average around unity. These results will be discussed in light of auditory neural computational models based on either place or temporal coding. [Work supported by the Division of Communication Disorders, University of Wyoming.]
Finite-difference modeling of the piano
Authors: Giordano N.
Published: October 2013

The construction of a complete computational model of the piano is described. This model treats the three major subsystems of the instrument: the hammers and strings, the soundboard, and the air (the sound radiation). Hammer nonlinearities and hysteresis are included, along with realistic stiff strings with frequency-dependent damping, following the work of Chaigne and Askenfelt. [Chaigne and A. Askenfelt, ‘‘Numerical simulations of piano strings. I. A physical model for a struck string using finite difference methods,’’ J. Acoust. Soc. Am. 95, 1112–118 (1994); A. Chaigne, J. Acoust. 5, 181 (1992)]. The strings are coupled to a soundboard model that includes the added thickness and stiffness of ribs and bridges. The vibrating soundboard drives the room air, with walls modeled through a complex acoustic impedance following Botteldooren. [D. Botteldooren, ‘‘Acoustical finite-difference time-domain simulation in a quasi-Cartesian grid,’’ J. Acoust. Soc. Am. 95 2313–2319 (1994); 98, 3302 (1995)]. All of the calculations take a finite difference approach, producing a time domain computation. Calculated tones are presented and future directions discussed. [Work supported in part by NSF grant PHY-9988562.]
Impaired frequency resolution in canaries with hereditary high-frequency hearing loss
Authors: Lauer Amanda , Dooling Robert , Leek Marjorie
Published: October 2013

Belgian Waterslager canaries (BWS), bred for a distinct low-pitched song, have an inherited high-frequency hearing loss related to hair cell abnormalities. Many hair cells are missing or damaged, and many of the remaining hair cells have abnormal stereocilia bundles. To investigate how the hair cell abnormalities affect frequency tuning along the BWS basilar papilla, we measured psychophysical tuning curves (PTCs) in BWS and normal-hearing non-BWS canaries using operant conditioning procedures. Non-BWS canaries showed relatively symmetrical tuning curves that became more narrowly tuned with increasing center frequency. Despite near-normal hearing at low frequencies, PTCs in BWS were elevated for all center frequencies tested. The sharpness of tuning was normal in BWS for PTCs with a center frequency of 1000 Hz and broader than normal at higher frequencies. The shapes of the PTCs were abnormal in BWS, particularly at higher frequencies. The abnormal tuning properties in the BWS are consistent with changes in the impedance characteristics of the basilar papilla due to structural damage. [Work supported by NIH DC01372 and DC04664.]
Naval sonar, marine mammal strandings, and the bubble hypothesis
Authors: Muller Mark W. , Au Whitlow W. L. , Allen John S. , Wezensky Eryn M. , Barkley Michael R.
Published: October 2013

Although spatio–temporal links exist between some military active sonar testing and cetacean mass stranding events, the underlying causal mechanism(s) of the strandings are not well understood. It has been demonstrated that cetaceans may experience in vivo gas bubble/emboli development; however, the basis for cavitation formation remains unknown. Acoustically mediated in vivo cavitation formation in cetaceans exposed to high-intensity sound sources has been proposed. The distance of these exposure effects from midfrequency sound sources can be influenced by a combination of factors affecting underwater acoustic propagation. To investigate these issues, this experiment considered rectified diffusion as a possible mechanism for acoustically mediated in vivo cavitation formation in cetaceans. Gelatin samples were placed under water and exposed to an SPL of 205 dB re: 1 μ Pa at 4.5 kHz for up to 1000 s. The sound field was generated by a Massa transducer similar to the transducer element used in the United States Navy AN/SQS–23 shipboard high–power sonar system. Exposure time threshold of cavitation formation was determined to be 600 s for the given sound field. Experimental results were compared with previously developed theoretical models for acoustically enhanced cavitation growth. The applicability and limitations of this approach as well as future research direction are discussed.
Low- to mid-frequency model of attenuation and dispersion.
Authors: Chotiros Nicholas P. , Isakson Marcia J. , Zhou Ji-Xun , Knobles David P.
Published: October 2013

A model of attenuation and sound speed in ocean sediments in the low- to mid-frequency range is presented. It is based on a combination of the Biot–Stoll and contact squirt and shear drag model [Chotiros and Isakson, J. Acoust. Soc. Am. 116, 2011–2022, (2004)] and the frame virtual mass model [Chotiros and Isakson, J. Acoust. Soc. Am. 121, EL70 (2007)]. This combination can match measured sound speeds below Wood’s equation lower bound and it addresses issues related to the Kramers–Kronig relationship. It is able to match both the sound speed dispersion and attenuation measurements from a large number of sites, including the sediment acoustics experiments (SAX99 and SAX04) in the Gulf of Mexico, the shallow water experiment on the Atlantic coast, and the Yellow Sea [Zhou, J. Acoust. Soc. Am. 78, 1003–1009 (1985)]. [Work supported by ONR, Ocean Acoustics.]
Measuring listening effort independent of task difficulty.
Authors: Shrivastav Mini , Shrivastav Rahul , Harnsberger James
Published: October 2013

The effects of task difficulty on many listening tasks are often confounded by those of the effort expended during the task. It is important to have valid measures of effort independent of task difficulty. The present experiment was aimed at doing so by measuring various markers of effort for listening conditions of varying difficulty but with equal performance. Task difficulty in a tone-detection experiment will be manipulated by changing the level of a broadband noise added to the background so that the signal-to-noise ratio changes from favorable to unfavorable. The participants will be a group of young normal-hearing individuals. Effort will be measured using several tools such as self-reported questionnaires and various physiological markers such as galvanic skin response, heart rate, and blood oxygen level. For each background noise condition, the percentage of correct detection performance will be calculated. Conditions that result in greater than 90% accuracy will be considered as having equal performance. Any difference in physiological measures between these conditions will then likely reflect differences in listening effort. The study will provide preliminary candidates for developing an objective and real-time measure of listening effort.
Nonlinear resonance frequency shifts in acoustical resonators with varying cross sections.
Authors: Ilinskii Yurii A. , Hamilton Mark F. , Zabolotskaya Evgenia A.
Published: October 2013

The frequency response and nonlinear resonance frequency shift for an acoustical resonator with losses and having a varying cross section were investigated previously using Lagrangian mechanics for resonator shapes that are close to cylindrical [J. Acoust. Soc. Am. 110, 109 (2001)]. The same approach is extended to include resonators having any shape for which a one-dimensional Webster-type equation is a valid model in the linear approximation. Admissible shapes include cones and bulbs proposed for acoustical compressors. The approach is appropriate for approximate but rapid parameter estimations for resonators with complicated shapes, requiring 100 times less computer time than for direct numerical solution of the one-dimensional model equation ordinarily used for these resonators [Ilinskii et al., J. Acoust. Soc. Am. 104, 2664 (1998)]. Results for cone and bulb shaped resonators with losses are compared with results from the previous one-dimensional theory and with experimental data. It is shown that the direction of the resonance frequency shift is determined by the efficiency of second-harmonic generation in modes having natural frequencies below versus above the frequency of the second harmonic, and how the net effect of this coupling compares with the frequency shifts due to cubic nonlinearity and static deformation.
Bistatic specular reflection by a rigid cone.
Authors: Marston Philip
Published: October 2013

It is possible to gain some insight into the high-frequency scattering of sound by objects in water by considering the presence or absence of rays constructed from geometric considerations. This presentation concerns the evolution of rays reflected from the sides of a vertical rigid cone for the case of illumination by a plane wave at an arbitrary grazing angle. The grazing angle with respect to a horizontal plane is usually taken to be small. The direction of the reflected rays depends on where the incident ray contacts the cone as specified by an azimuthal angle viewed from above. Define the meridional plane as that plane which contains the incident wave vector and the axis of the cone. Incident rays offset from the meridional plane can be reflected with relatively small vertical components in their wave vector. This analysis has implications for how bistatic hydrophones may be deployed to detect specular glints from cone-shaped objects. There may also be implications for understanding the high-frequency scattering by conical seamounts in deep water. [Research supported by ONR.]
Image-based refocusing of ultrasound arrays in the presence of strongly scattering objects.
Authors: Ballard John , Ebbini Emad
Published: October 2013

Ultrasound phased arrays are currently being investigated for a dual-mode (imaging/therapy) operation in targeting deep-seated abdominal tumors for selective destruction noninvasively. In some cases, e.g., liver tumors, the target is partially obstructed by the ribcage, which limits the array gain at the target. In addition, the intensity at the ribs may be high enough to cause treatment-limiting pain and/or collateral damage to the tissues surrounding the ribs in the path of the therapeutic beam. Using the imaging capabilities of these dual-mode arrays, we have formulated and experimentally verified a robust minimum variance beamforming algorithm for adaptive refocusing in the presence of the ribs. The algorithm utilizes image data of the treatment region formed using conventional beamforming in estimating the array steering vector at the target and the weighting matrix that maximizes the array gain at the target. In this paper, we will describe the mathematical formulation and present experimental data to demonstrate its robustness. We will also discuss the implications of the method, the use of ultrasound phased arrays for imaging, and therapy of trans-thoracic targets such as the liver and the heart.
Higher-order statistical analysis of nonlinearly propagated broadband noise.
Authors: Shepherd Micah R. , Gee Kent L.
Published: October 2013

Nonlinearity indicators have recently been used to identify and characterize nonlinear effects present in high-amplitude noise propagation. Although frequency-domain approaches have many benefits, a time-domain approach may be a more natural fit for the time-domain phenomenon of wave form steepening and shock formation. Standard skewness and kurtosis metrics are computed for propagated Gaussian noise at both low and high amplitudes. The same higher-order statistics are also computed for the first time derivative of the propagated noise in order to accentuate non-Gaussian variation in the wave form. The results appear to reveal an asymptotic behavior of the statistical quantities as the time wave form becomes more shock dominated.
Anisotropic properties of long-time intensity fluctuations of midfrequency signals in presence of intense internal waves in shallow water.
Authors: Katsnelson Boris , Grigorev Valery , Lynch James
Published: October 2013

Intensity fluctuations of sequence of midfrequency pulses radiated for 5 h in SW06 experiment were considered. Frequency band of pulses is 2–10 kHz; they were radiated by the source (R/V Knorr) with the interval about 15 s and received by four hydrophones (SHRUs) placed at the distances from 4 to 14 km and different directions (SW, SSW, NE, and NNE) from the source. During this time period, remarkable train of internal waves (amplitude of displacement up to 15 m) passed toward coastal line at the velocity of 0.6 m/s. Angles between wave front of train and acoustical tracks were about 65–80 deg. Mechanism providing sound fluctuations in this case is mode coupling (for the low-frequency signals) or additional scattering of rays by internal waves (in high- or midfrequency situation). It was shown that temporal fluctuations of the sound intensity of received pulses initiated by internal waves have spectra, depending on the direction of propagation of internal wave relative acoustic track. Results of comparison of experimental data with theoretical estimations demonstrate good consistency. [This work was supported by ONR and RFBR.]
Point process models of distinctive feature landmarks for speech recognition.
Authors: Jansen Aren , Niyogi Partha
Published: October 2013

Several interrelated strands of research in linguistics, acoustic phonetics, and cognitive neuroscience suggest a host of new directions for the development of end-to-end computational models of speech perception and recognition. Natural candidates for exploration include (i) phonological representations in terms of distinctive features; (ii) nonlinear detectors for distinctive feature landmarks (or any other set of perceptually salient acoustic events), which define a sparse point process representation of the speech signal; (iii) syllable-metered temporal processing and/or syllable-sized integration windows; and (iv) point process models and hierarchical strategies for recognizing words, syllables, phonemes, and features. A computational framework around these ideas has been developed and has led to phonetic recognition and keyword spotting performance that is competitive with equivalent hidden Markov model-based systems. This framework thus connects a computational platform for benchmarking competing scientific theories with simultaneous advancement toward a viable technological solution to the speech recognition problem.
Biomedical imaging for the study of auditory processes in the bottlenose dolphin.
Authors: Houser Dorian , Ridgway Sam , Moore Patrick , Finneran James
Published: October 2013

The use of medical imaging techniques in marine mammalogy has traditionally consisted of anatomical investigations within postmortem specimens. Within the last decade, Ridgway pioneered the use of in vivo scanning techniques to study physiological processes in the bottlenose dolphin. His work utilizing PET and SPECT imagings to study processes that occur during half-brain sleep and long-term persistent vigilance have opened avenues for marine mammal research not previously realized. Leveraging off of the successes of Ridgway, new work on the processing of auditory signals in the dolphin brain is underway. A dolphin is trained to perform an echolocation task while out of water. Echolocation clicks are captured at the melon surface with a suction-cup embedded hydrophone and synthetic target echoes are returned to the dolphin via a jawphone attached to the pan of the lower jaw. Under this paradigm, the dolphin performs a target discrimination task while positioned in a PET scanner. Injection of radiotracers at the time of the discrimination task will be used to map regions of blood flow and/or metabolic activity during the task. Results will provide the first visualization of regional physiological processes associated with the processing of echoic information in the dolphin brain.
Water flow detection by larval bullfrogs (Rana catesbeiana): Learning and group effects.
Authors: Stamper Sarah A. , Simmons Andrea Megela
Published: October 2013

The lateral line system in bullfrog tadpoles (Rana catesbeiana) detects water current but mediates orientation away from, rather than toward, the source of current flow. In these experiments, we examined the effects of repeated testing and of group formation on flow detection. Tadpoles (Gosner stages 24–28) were placed in a laminar flow tank in which visual, olfactory, and auditory cues were controlled. Each animal was tested multiple times per day and across multiple days. All animals oriented away from the flow. In addition, the mean latency to adopt a stable position in the tank significantly decreased as a function of repeated testing both within and across days. In a second experiment, animals were tested in groups. Under these conditions, interanimal distances declined significantly at higher flow rates. These experiments suggest that orientation away from water flow in the larval bullfrog may function to facilitate avoidance of current flow produced by approaching predators. In this case, tadpoles should show a preference for locations with reduced water flow and they would benefit from remembering these locations and finding them quickly. Tadpoles would also benefit from forming aggregations in the presence of flow, if potentially generated by a predator, because of dilution effects.
Applying well-known diffraction models to the sound field in the shadow zone of an isolated building.
Authors: Alberts W. C. Kirkpatrick , Noble John M. , Coleman Mark A.
Published: October 2013

An isolated building, a fundamental case of urban acoustics, has recently been the subject of an experimental effort to characterize the building’s influence on propagating sound [Alberts and Noble, J. Acoust. Soc. Am. 121, 3064 (2007)]. As a precursor to modeling efforts involving finite-difference time-domain simulations, two common diffraction models, the frequency domain model of Pierce and Medwin’s extension of Biot and Tolstoy’s time-domain model, have been utilized to estimate the sound pressure at various locations in the building’s acoustic shadow. The discussion will include the models used and comparisons between calculated and measured data, demonstrating reasonable agreement between measured and calculated spectra in limited cases at some frequencies.
Identification of Mandarin coarticulated tones by inexperienced and experienced English learners of Mandarin.
Authors: He Yunjuan , Wayland Ratree
Published: October 2013

Two groups of native English speakers, relatively inexperienced (IE) (N=14) with 4 months of Mandarin study and relatively more experienced (EE) (N=14) with 12 months of study, were asked to identify coarticulated Mandarin lexical tones in disyllabic words. The results show that the EE group was better at identifying Mandarin tones than the IE group. Interestingly both groups were more accurate at identifying tones of the second (i.e., last) syllables than tones of the first syllables. Two types of errors were found in both groups: tonal direction misperception and tonal height misperception. EE committed fewer tonal direction errors than IE. However, EE still made considerable amount of tonal height errors. These results suggest the following: (1) The ability to perceive coarticulated tones improves with learning experience. (2) Due perhaps to a recency effect, final tones are remembered better than initial tones, and final syllable tones are misperceived less frequently than initial syllable tones. (3) The ability to identify tonal direction may improve faster than the ability to identify tonal height among English speakers and thus while tonal direction errors decrease with experience, misperception of tonal height remains even with increasing learning experience.
Draft Genome Sequences of Bordetella hinzii and Bordetella trematum
Authors: Shah N. R. , Moksa M. , Novikov A. , Perry M. B. , Hirst M. , Caroff M. , Fernandez R. C.
Published: October 2013

Bordetella hinzii
colonizes the respiratory tracts of poultry but can also infect immunocompromised humans.
Bordetella trematum
, however, only infects humans, causing ear and wound infections. Here, we present the first draft genome sequences of strains
B. hinzii
ATCC 51730 and
B. trematum
CCUG 13902.
Genome of the Root-Associated Plant Growth-Promoting Bacterium Variovorax paradoxus Strain EPS
Authors: Han Jong-In , Spain Jim C. , Leadbetter Jared R. , Ovchinnikova Galina , Goodwin Lynne A. , Han Cliff S. , Woyke Tanja , Davenport Karen W. , Orwin Paul M.
Published: October 2013

Variovorax paradoxus
is a ubiquitous betaproteobacterium involved in plant growth promotion, the degradation of xenobiotics, and quorum-quenching activity. The genome of
V. paradoxus
strain EPS consists of a single circular chromosome of 6,550,056 bp, with a 66.48% G+C content.
Improving the quality of written information available at weekends in a paediatric hospital: the TRANSMIT sheet
Authors: Hawcutt Daniel , Green Julie , Durand Charlotte , Mehta Fulya , Christopherson Matthew , Sinha Ian
Published: October 2013

The clinical outcomes at weekends are worse than during the week in a hospital setting. There are many potential factors which influence this. High quality communication between the weekday teams and the on call weekend staff could help improve clinical outcomes at weekends, but there are no validated forms of communication that have been established in a paediatric hospital setting.

The casenotes of all medical patients (n=119) were prospectively evaluated across all medical wards in a large paediatric hospital over three weekends, to establish the quality of information available to on call teams. Following introduction of structured documentation, known as a TRANSMIT (including Tasks, Respiratory, Anticipated problems, Nutrition, Sepsis, Medication, Intravenous access, Transfer/discharge) sheet, the audit was repeated (n=111). A qualitative survey of junior doctors using TRANSMIT was carried out after introduction.

Prior to the introduction of the structured documentation (TRANSMIT sheet) an accurate problem list was present in 56% (67/119), and an adequate written management plan in 63% (75/119). Following introduction, an improvement in the notes was seen, with accurate problem lists in 82% (91/111) and an adequate plan in 76% (84/111). Improvements in the quantity and quality of information available to weekend on call medical staff were noted.

The use of a structured documentation (TRANSMIT sheet) can improve the quality of written information available to on-call teams in a paediatric hospital setting. A retrospective qualitative assessment of junior doctors using TRANSMIT sheets showed an improvement in both the quantity and quality of information available to on call staff at weekends.
Graduate employment survey: going behind the figures
Authors: Brown Peter
Published: October 2013

The preliminary results of a recent RCVS/IES survey have raised concerns about the employment of new graduates. But are these concerns justified? asks Peter Brown
Taking a history on veterinary education
Authors: Gardiner Andrew , Rhind Susan
Published: October 2013

In this article, another in the series marking 125 years of Veterinary Record, Andrew Gardiner and Susan Rhind consider some common themes in the history of veterinary education. They look at how veterinary teaching and education have evolved over time and discuss what may happen in years to come.
A spatial age-structured model for describing sea lamprey (Petromyzon marinus) population dynamics
Authors: Robinson Jason M. , Wilberg Michael J. , Adams Jean V. , Jones Michael L.
Published: October 2013

The control of invasive sea lampreys (Petromyzon marinus) presents large-scale management challenges in the Laurentian Great Lakes. No modeling approach has been developed that describes spatial dynamics of lamprey populations. We developed and validated a spatial and age-structured model and applied it to a sea lamprey population in a large river in the Great Lakes basin. We considered 75 discrete spatial areas, included a stock–recruitment function, spatial recruitment patterns, natural mortality, chemical treatment mortality, and larval metamorphosis. Recruitment was variable, and an upstream shift in recruitment location was observed over time. From 1993 to 2011, recruitment, larval abundance, and the abundance of metamorphosing individuals decreased by 80%, 84%, and 86%, respectively. The model successfully identified areas of high larval abundance and showed that areas of low larval density contribute significantly to the population. Estimated treatment mortality was less than expected but had a large population-level impact. The results and general approach of this work have applications for sea lamprey control throughout the Great Lakes and for the restoration and conservation of native lamprey species globally.
Effects of an invasive herbivore at the single plant scale do not extend to population-scale seedling dynamics
Authors: Coyle David R. , Mattson William J. , Friend Alexander L. , Raffa Kenneth F.
Published: October 2013

A complex of nine invasive weevils has established in the northern hardwood forests of the Great Lakes Region. These weevils have become the numerically dominant arthropod fauna in the lower vegetation strata of this ecosystem. Effects of these folivorous adults and rhizophagous larvae on seedling survival and density are unknown. We measured the impact of adult weevil defoliation on individual sugar maple (Acer saccharum Marshall) seedlings, the numerically dominant flora in these stands. Over 14 500 seedlings were measured to examine the effects of larval abundance, adult abundance, and adult defoliation on seedling dynamics during 2005–2009. Heavy defoliation led to individual sugar maple seedling mortality. However, at the stand level there was no measureable net effect of invasive weevils against the high natural background rates of seedling mortality. Seedling growth and biomass were reduced by high adult or larval populations, which were associated with heavy leaf and root herbivory, but not by moderate adult or larval populations. We conclude that high levels of redundancy and compensatory processes in this environment allow sugar maple seedling populations to tolerate high levels of weevil damage, although additional stresses could reduce this resilience.
Exciton dissociation and design optimization in P3HT:PCBM bulk-heterojunction organic solar cell
Authors: Narayan Monishka Rita , Singh Jai
Published: October 2013

The rate of Frenkel exciton dissociation in P3HT:PCBM bulk-heterojunction organic solar cell was calculated using the newly derived interaction operator between charge transfer exciton and molecular vibrational energy. The PCBM LUMO energy levels were tuned to investigate their impact on the rate of dissociation of a Frenkel exciton into free pair of electron and hole. In the latter part of the study, the PCBM LUMO energy level was set to −4.10 eV and design optimization was performed on PET/PEDOT:PSS/TFB/ P3HT:PCBM/Ca bulk-heterojunction organic solar cell using the semiconducting thin film optics simulation software. Each of the layer thicknesses were optimized for maximum photon absorbance in the P3HT:PCBM active layer and a high power conversion efficiency of 7.46% was obtained.
ITERATIVE SELF-LABELING DOMAIN ADAPTATION FOR LINEAR STRUCTURED IMAGE CLASSIFICATION
Authors: HABRARD AMAURY , PEYRACHE JEAN-PHILIPPE , SEBBAN MARC
Published: October 2013

A strong assumption to derive generalization guarantees in the standard PAC framework is that training (or source) data and test (or target) data are drawn according to the same distribution. Because of the presence of possibly outdated data in the training set, or the use of biased collections, this assumption is often violated in real-world applications leading to different source and target distributions. To go around this problem, a new research area known as Domain Adaptation (DA) has recently been introduced giving rise to many adaptation algorithms and theoretical results in the form of generalization bounds. This paper deals with self-labeling DA whose goal is to iteratively incorporate semi-labeled target data in the learning set to progressively adapt the classifier from the source to the target domain. The contribution of this work is three-fold: First, we provide the minimum and necessary theoretical conditions for a self-labeling DA algorithm to perform an actual domain adaptation. Second, following these theoretical recommendations, we design a new iterative DA algorithm, called GESIDA, able to deal with structured data. This algorithm makes use of the new theory of learning with (ε,γ,τ)-good similarity functions introduced by Balcan et al., which does not require the use of a valid kernel to learn well and allows us to induce sparse models. Finally, we apply our algorithm on a structured image classification task and show that self-labeling domain adaptation is a new original way to deal with scaling and rotation problems.
A REAL-TIME BURST ANALYSIS METHOD
Authors: EBINA RYOHEI , NAKAMURA KENJI , OYANAGI SHIGERU
Published: October 2013

A burst is an unusually large number of events occurring within a certain period of time. Various burst analysis methods over multiple window size have been proposed. However, real-time burst analysis is difficult owing to the huge amount of computation. This article proposes a method to analyze a burst in real-time. The proposed method reduces computation by avoiding redundant data updates of no event occurrence, and by suppressing data within a certain period in the case of emergent increase of events. In addition, a level and a rank of a burst can be analyzed simultaneously. The effectiveness of the proposed method is evaluated by experiments with real data. The result shows that the proposed method is more effective in analyzing real data, and more efficient in handling a large amount of events.
EPIDEMIOLOGY OF HAND INFECTION — A COMPARATIVE STUDY BETWEEN YEAR 2000 AND 2009
Authors: Chong Chew-Wei , Ormston Vicky Ellen , Tan Agnes Beng-Hoi
Published: October 2013

This study aims to analyze the bacteriology and antibiotic resistance in hand infection between 2000 and 2009 at a local hospital in Asia. It is a retrospective study involving all adult patients with hand infections that were treated surgically, with tissue or wound culture sent. A total of 100 cases in 2000 and 98 cases in 2009 were included in this study. Standard epidemiology information, bacteriology, antibiotic sensitivity and treatment outcome were analyzed. Particular interest was given to diabetic hand infection. There was no significant difference of outcome in hand infection between the two years. The outcome of diabetics was not statistically worse than the non-diabetics. Comparing the patients in 2000 and 2009, more younger patients were affected with hand infection in 2009. While length of stay is shorter in 2009. Mixed infection was more common in diabetics in 2009. There was trend of clindamycin resistance in methicillin-sensitive staphylococcus aureus in 2009.
ASSESSING THE VARIABILITY OF INJECTATE DISTRIBUTION FOLLOWING CARPAL TUNNEL INJECTION — A CADAVERIC STUDY
Authors: Jariwala A. , Zaliunaite R. , Soames R. , Wigderowitz C. A.
Published: October 2013

This anatomical study was designed to assess the distribution of a solution (injectate) made up using local anesthetic, steroid and dye into the carpal tunnel using a commonly used injection technique. Dissections were undertaken in 29 embalmed cadaveric wrists. The cadaveric specimens were dissected 24 hours after injection to observe the effect of time on diffusion patterns in both superficial and deep planes.

Eighteen of the 29 specimens showed the presence of the injectate in the superficial plane and three preferential patterns of distribution were noted in the deep plane: free in the carpal tunnel, exclusively in the tendon sheath and mixed.

This is the first study investigating the delayed diffusion pattern of injectate in the carpal tunnel and illustrates its variability. The findings of variable degree of superficial diffusion and different patterns of intracarpal spread help to offer some explanation regarding the variability of the response following carpal tunnel injection.
RETROSPECTIVE ANALYSIS OF FIVE-YEAR AND LONGER CLINICAL AND ELECTROPHYSIOLOGICAL RESULTS OF THE WORLD'S FIRST ENDOSCOPIC MANAGEMENT FOR CARPAL TUNNEL SYNDROME
Authors: Okutsu Ichiro , Hamanaka Ikki , Yoshida Aya
Published: October 2013

We have analyzed postoperative long-term follow-up results of five years or more from idiopathic carpal tunnel syndrome patients that underwent our complete carpal canal release and decompression procedure that uses the Universal Subcutaneous Endoscope system. In this series, 203 hands were followed up both clinically and electrophysiologically. Final follow-up times were determined by the most recent electrophysiological measurements. Mean follow-up period was nine years. Tingling, pain (using a 3 gm needle) and touch (using a 2 gm von Frey hair) at all median nerve distribution areas recovered to normal in 92.9, 98.2, 95.2%, respectively. Abductor pollicis brevis muscle power improved from preoperative manual muscle testing of 0, 1, 2 to post-operative 4 or 5 in 82.6%. Mean detectable distal sensory latency improved from 4.3 (n = 130) to 3.1 msec (n = 200). Mean detectable distal motor latency improved from 6.2 (n = 189) to 4.1 msec (n = 200). Complication and recurrence rates were 0% and 0.5% respectively.
SUCCESSFUL REPLANTATION OF A FINGER IN AN 8-MONTH OLD CHILD
Authors: Stewart D. A. , Coombs C. J.
Published: October 2013

A successful replantation of an index fingertip in an 8-month old girl is reported. A literature review of replants in very young children suggests this is one of the youngest patients ever to undergo digital replantation and possibly the youngest finger replant performed.