bluuebunny/crossref_metadata_2025 huggingface dataset:
Relationship Between Arrhythmogenic Pulmonary Veins and the Surrounding Atrial Substrate in Patients with Paroxysmal Atrial Fibrillation
Authors: SUENARI KAZUYOSHI , LIN YENN‐JIANG , CHANG SHIH‐LIN , LO LI‐WEI , HU YU‐FENG , TUAN TA‐CHUAN , HUANG SHIH‐YU , TAI CHING‐TAI , NAKANO YUKIKO , KIHARA YASUKI , TSAO HSUAN‐MING , WU TSU‐JUEY , CHEN SHIH‐ANN
Published: October 2010

Arrhythmogenic PVs and the Fibrillatory Activities. Introduction: The relationship between pulmonary veins (PVs) with atrial fibrillation (AF) initiating triggers and their surrounding atrial substrate has not been elucidated. We aimed to clarify the atrial substrate properties around the PVs.

Methods and Results:
Twenty‐three paroxysmal AF patients were studied with the identification of PV initiating triggers. High‐density mapping of the dominant frequency (DF, 1200 Hz) and the mean degree of the complex fractionated electrograms (CFE mean interval over 6 seconds) was evaluated in 2 zones (zone 1: < 5 mm, zone 2: 5–15 mm from the PVs) and the left atrial (LA) using a NavX system prior to the PV isolation. High‐DFs (>8 Hz) and continuous CFEs (<50 ms) were identified in 1.5 ± 0.9 and 2.3 ± 1.1 regions per patient, respectively. Most of the high‐DF regions (86%) and continuous CFE regions (77%) were located within 15 mm of the PV ostia. Of those, 75% of the high‐DF regions and 54% of the continuous CFE regions were related to arrhythmogenic PVs. There was a significant DF gradient from arrhythmogenic PV zone 1 to zone 2, while the mean CFE exhibited a significant gradient between arrhythmogenic PV zone 2 and the rest of the LA. Additionally, 69% of the procedural AF termination sites were at arrhythmogenic PV zone 2.

Conclusion:
Evaluation of the atrial substrate properties may be useful for locating arrhythmogenic PVs during AF and defining the extent of the circumferential PV isolation. (J Cardiovasc Electrophysiol, Vol. 22, pp. 405‐410)
The Development of Analytical and Interpretational Protocols to Facilitate the Provenance Establishment of Polycarbonate Headlamp Lens Material*
Authors: May Christopher D. , Watling R. John
Published: October 2010

Abstract:  Despite the forensic significance of polycarbonate headlamp lenses, robust analytical protocols to facilitate their discrimination are scarce. In this study, laser ablation inductively coupled plasma mass spectrometry has been applied to the analysis of polycarbonate headlamp lenses with multivariate chemometrics techniques utilized to facilitate interpretation of the data. The analytical protocol involves the analysis of 46 analytes on material comprising the exterior surface of the lens. Using this data, it was found that although minor variation exists within a single headlamp lens, discrimination between lenses produced from a single manufacturing plant was still possible using iterative forward stepwise linear discriminant analysis processes. Discrimination between all headlamp lenses, with the exception of some lenses produced on the same day in a single plant, could be achieved using the analytical protocol. Furthermore, an interpretational protocol has been developed that has successfully classified all tested headlamp lens samples, within the discrimination limits of the analytical method.
Macro–micro feedback links of water management in South Africa: CGE analyses of selected policy regimes
Authors: Hassan Rashid , Thurlow James
Published: October 2010

The pressure on an already stressed water situation in South Africa is predicted to increase significantly under climate change, plans for large industrial expansion, ongoing rapid urbanization, and government programs to provide access to water to millions of previously excluded populations. This article employs a general equilibrium approach to examine the economy‐wide impacts of selected macro and water‐related policy reforms on water use and allocation, rural livelihoods, and economy at large. The analyses reveal that implicit crop‐level water quotas reduce the amount of irrigated land allocated to higher‐value horticultural crops and create higher shadow rents for production of lower‐value water‐intensive field crops, such as sugarcane and fodder. Accordingly, liberalizing local water allocation within irrigation agriculture is found to work in favor of higher‐value crops, and expand agricultural production and exports and farm employment. Allowing for water trade between irrigation and nonagricultural uses fuelled by higher competition for water from urbanization leads to greater water shadow prices for irrigation water with reduced income and employment benefits to rural households and higher gains for nonagricultural households. The analyses show difficult trade‐offs between general economic gains and higher water prices, which place serious questions on subsidizing water supply to irrigated agriculture, i.e., making irrigation subsidies much harder to justify.
Ethnic inequity in neonatal survival: a case‐referent study in northern Vietnam
Authors: Målqvist Mats , Nga Nguyen Thu , Eriksson Leif , Wallin Lars , Hoa Dinh Phuong , Persson Lars Åke
Published: October 2010

Aim:  In this study from Quang Ninh province in northern Vietnam (sub‐study of the trial Neonatal Health – Knowledge into Practice, NeoKIP, ISRCTN 44599712), we investigated determinants of neonatal mortality through a case‐referent design, with special emphasis on socio‐economic factors and health system utilization.

Methods:  From July 2008 until December 2009, we included 183 neonatal mortality cases and 599 referents and their mothers were interviewed.

Results:  Ethnicity was the main socio‐economic determinant for neonatal mortality (OR 2.08, 95% CI 1.39–3.10, adjusted for mothers’ education and household economic status). Health system utilization before and at delivery could partly explain the risk elevation, with an increased risk of neonatal mortality for mothers who did not attend antenatal care and who delivered at home (OR 4.79, 95% CI 2.98–7.71). However, even if mothers of an ethnic minority attended antenatal care or delivered at a health facility, the increased risk for this group was sustained.

Conclusion:  Our study demonstrates inequity in neonatal survival that is related to ethnicity rather than family economy or education level of the mother and highlights the need to include the ethnic dimension in the efforts to reduce neonatal mortality.
COSMOPOLITANISM IN RELATION TO THE SELF AND THE OTHER: FROM MICHEL FOUCAULT TO STANLEY CAVELL
Authors: Smeyers Paul , Waghid Yusef
Published: October 2010

Educators, not to mention philosophers of education, find themselves in a difficult position nowadays. They are confronted with problems such as which kind of values one would want citizens to embrace, or to what extent social practices of a particular group may differ from what is generally held. In this essay, Paul Smeyers and Yusef Waghid focus on postmodern critiques, in particular on the position of Michel Foucault as it is relevant for the debate on cosmopolitanism. The authors argue that Foucault's analysis of the self in relation to the other is somewhat contentious, as it seems to invoke an independent ethical self other than a social self. Smeyers and Waghid claim that a more nuanced position regarding this relation can be found in the work of Stanley Cavell. They conclude that encounters with the other should not be seen as a new kind of universalism or Foucauldian subjectivism, but rather as an opening that creates opportunities both for attachment and detachments, that is, for acknowledgment and avoidance.
DEMOCRACY AND EDUCATION IN THE TWENTY‐FIRST CENTURY: DEWEYAN PRAGMATISM AND THE QUESTION OF RACISM
Authors: Neubert Stefan
Published: October 2010

Why is John Dewey still such an important philosopher today? Writing from the perspective of the Cologne Program of Interactive Constructivism, Stefan Neubert tries in what follows to give one possible answer to this question. Neubert notes that Cologne constructivism considers Dewey in many respects as one of the most important predecessors of present‐day constructivism and regards Deweyan pragmatism as one of its most important dialogue partners in contemporary discussions about pragmatism and constructivism in philosophy and education. Among the many aspects in which Dewey's works still speak powerfully to us today, Neubert highlights in this essay one theme that is at the heart of Dewey's philosophical approach: the relation between democracy and education.
The latitude dependence of the rotation measures of NVSS sources
Authors: Schnitzeler D. H. F. M.
Published: October 2010

In this Letter I use the variation of the spread in rotation measure (RM) with Galactic latitude to separate the Galactic from the extragalactic contributions to RM. This is possible since the latter does not depend on Galactic latitude. As input data I use RMs from the catalogue by Taylor, Stil & Sunstrum, supplemented with published values for the spread in RM (‘σRM’) in specific regions on the sky. I test four models of the free-electron column density (which I will abbreviate to ‘DM∞’) of the Milky Way, and the best model builds up DM∞ on a characteristic scale of a few kpc from the Sun. σRM correlates well with DM∞. The measured σRM can be modelled as a Galactic contribution, consisting of a term σRM,MW that is amplified at smaller Galactic latitudes as 1/sin |b|, in a similar way to DM∞, and an extragalactic contribution, σRM,EG, that is independent of latitude. This model is sensitive to the relative magnitudes of σRM,MW and σRM,EG, and the best fit is produced by σRM,MW≈ 8 rad m−2 and σRM,EG≈ 6 rad m−2. The four published values for σRM as a function of latitude suggest an even larger σRM,MW contribution and a smaller σRM,EG. This result from the NVSS RMs and published σRM shows that the Galactic contribution dominates structure in RM on scales between about 1° and 10° on the sky. I work out which factors contribute to the variation of σRM with Galactic latitude, and show that the σRM,EG I derived is an upper limit. Furthermore, to explain the modelled σRM,MW requires that structure in 〈B∥〉 has a 1σ spread ≲0.4 μG.
Cycle of sexual assault and women's alcohol misuse
Authors: Kalmakis Karen A.
Published: October 2010

Purpose: To describe the complex relationship between sexual assault and alcohol misuse by female assault victims.

Data sources: Drawing on recent research and theoretical models from other social sciences, the author interjects a nursing perspective for this complex patient problem.

Conclusions: This review of theories and models, and the evidence that supports them, provides a way for nurses to conceptualize the relationship between sexual victimization and alcohol misuse as bidirectional or reciprocal.

Implications for practice: The evidence and models discussed here suggest that when patients present with sexual assault or alcohol misuse, nurses should assess and address the possibility of both conditions being present.
Chemical Space Sampling in Virtual Screening by Different Crystal Structures
Authors: Brooijmans Natasja , Humblet Christine
Published: October 2010

Retrospective virtual screening experiments were carried out to investigate the effects of combining hit lists from different crystal structures of the same target using consensus scoring. An in‐house High Throughput Screening (HTS) dataset from PI3K‐γ was used and docked against five diverse PI3K‐γ crystal structures. The results show that consensus scoring prioritizes compounds that score moderately against individual crystal structures and is thus complementary to individual crystal structure screening leading to an increase in the diversity of hits. Enrichment factors (EFs) of the consensus score for two or three structures are often as high as or higher than the EF of the individual structures used in the consensus score. Combining four or five structures in the consensus score generally yields lower enrichments. Compounds in the top 500 of the consensus score that are also found in the top 500 of an individual X‐ray structure used in the consensus score calculations yield the largest number of hits with the lowest number of false positives.
BION, BECKETT AND BOB
Authors: Gordon John , Kirtchuk Gabriel
Published: October 2010

abstract

We worked with Bob Hinshelwood for many years and begin our paper with an account of what we experienced as the essence of his approach in applying psychoanalytic understanding, especially an awareness of the ubiquitous effects of projective identification, to individual, group and organizational dynamics in mental health settings. This takes the form of a juxtaposition of some ideas and responses triggered by contact with patients expressed by Bion, Samuel Beckett and Bob himself. They all conveyed what it feels like when ‘bits of identity’ are passed around through unconscious interpersonal interactions. We then introduce the forensic psychotherapy context in which we work and try to apply what Bob helped us to see. Contact with severely mentally ill patients, who have committed catastrophic assaults, is work on the countertransference edge where patients' deficit in the capacity for symbolic communication and subsequent resort to action – sustained streams of projective identifications – evoke the maximum emotional impact in staff. We conclude with an example of a reflective practice group for beleaguered, often frightened, staff who desperately need but also attack – much as their patients do – what Bob called the attempt to build a reflective space which is so vital to survival and effective work.
BEHIND LOCKED DOORS: AN EXPLORATION OF THERAPEUTIC PROCESSES WITHIN A PRISON THERAPEUTIC COMMUNITY
Authors: Polden Jane
Published: October 2010

abstract

Supervision work in a prison Therapeutic Community is used to explore countertransference implications for staff engaging with residents' disturbed states of mind. Parallel process (a psychoanalytic concept supported by contemporary neurological findings and particularly relevant to supervisory relationships) is used to explore vulnerabilities within the staff group towards acting out the dynamics they are working with therapeutically such as attacks on linking, feelings of helplessness and cynicism, and the denial of aggression. Conversely, the development and reinforcement of the staff group's capacity to generate and preserve a thinking space while under threat has a therapeutic effect upon residents' states of mind, again through the workings of parallel process. The establishment of this benign parallel process is a central task of the Therapeutic Community, and underpins its effectiveness. Its relevance for effective therapy with disturbed states of minds in other settings is also considered.
Museums as Restorative Environments
Authors: Packer Jan , Bond Nigel
Published: October 2010

Abstract  Restorative environments possess a combination of attributes that facilitate recovery from mental fatigue. Most previous research in this regard has focused on natural environments, but this paper explores the extent to which museum environments also provide access to restorative experiences. Visitors (307 tourists and 274 local residents) to a history museum, an art museum, an aquarium, and a botanic garden completed a questionnaire regarding the restorative qualities and benefits of the environment they visited. The findings indicate that for some people, museums are at least as restorative as natural environments. The paper contributes to the development of a theoretical understanding of museums as restorative environments and provides insights into the factors that facilitate and enhance restorative experiences. Such experiences have the potential to contribute to visitors’ well‐being and satisfaction.
The Laboratory on 53rd Street: Victor D’Amico and the Museum of Modern Art, 1937–1969
Authors: Rasmussen Briley
Published: October 2010

Abstract  This essay addresses the pioneering work of Victor D’Amico, the first director of education at the Museum of Modern Art (MoMA) and an influential art educator. During his tenure at MoMA, D’Amico explored the role of museums in developing creativity through direct aesthetic experience and the larger social implications of art museum education. Victor D’Amico led the Education Project at MoMA, which began as a part‐time school partnership program in 1937. By the time he retired in 1969, he had become an internationally recognized leader in the field of art museum education. Yet today his influence is little known and seldom discussed. This essay focuses on two important programs he developed at MoMA: his most widely acclaimed and influential program, the Children’s Art Carnival (1942‐1969), and the groundbreaking art education television series Through the Enchanted Gate (1952‐1953).
Ideas, Objects, or People? A Smithsonian Exhibition Team Views Visitors Anew
Authors: Pekarik Andrew J. , Mogel Barbara
Published: October 2010

Abstract  An exhibition team at the National Museum of the American Indian, working with a visitor studies specialist from the Smithsonian’s Office of Policy and Analysis, used visitor studies conducted by the entire team during planning for a reinstallation of part of the permanent collection. The studies evolved organically during the exhibition planning as questions and hypotheses arose among the team. The answers led to further studies. This research model brought team members together in a spirit of inquiry and a process of discovery, changed their perceptions of themselves and their subjects, and suggested a new typology of visitors.
Artistic Practice and (Museum) Ethnography
Authors: Durand Carine Ayele
Published: October 2010

Abstract In this study of artistic practice surrounding the development of thePasifika Stylesexhibition at the Museum of Archaeology and Anthropology (Cambridge), the author argues that certain methodologies employed in artistic practice, such as techniques of assemblage, not only suggest ways in which collaborative initiatives between museums and their communities can be realized, they also offer practical direction for the development of complementary ethnographic techniques. Interest among museum practitioners in what artists can offer museums is explored in relation to their increasing need to demonstrate their social relevance.
Mask-topography-induced phase effects and wave aberrations in optical and extreme ultraviolet lithography
Authors: Erdmann A. , Shao F. , Evanschitzky P. , Fühner T.
Published: October 2010

Rigorous electromagnetic field simulations are applied to investigate phase effects in the light diffraction from masks for advanced optical and extreme ultraviolet lithography. Analogies of these phase effects with wave aberrations of the projection lens and their impact on the lithographic process performance are discussed.
Defect analysis for patterned media
Authors: Ye Zhengmao , Fretwell John , Luo Kang , Ha Steven , Schmid Gerard , LaBrake Dwayne , Resnick Douglas J. , Sreenivasan S. V.
Published: October 2010

Imprint lithography has been shown to be an effective technique for the replication of nanoscale features. Acceptance of imprint lithography for manufacturing will require a demonstration of defect levels commensurate with cost-effective device production. This article summarizes the results of defect inspections of hard disks patterned using jet and flash imprint lithography (J-FIL™). This work presents a methodology for automated pattern inspection and defect classification for imprint-patterned media. Candela CS20 and 6120 tools from KLA-Tencor map the optical properties of the disk surface, producing high-resolution grayscale images of surface reflectivity and scattered light. Defects that have been identified in this manner are further characterized according to the morphology. The imprint process was tested after optimizing both the disk cleaning and adhesion layer processes that precede imprinting. Two extended imprint runs were performed and both the defect types and trends are reported.
Mechanical and electronic characteristics of scanning probe microscopy probes based on coaxial palladium nanowire/carbon nanotube hybrid structures
Authors: Clark Ian Thomas , Rius Gemma , Matsuoka Yuki , Yoshimura Masamichi
Published: October 2010

The authors present the mechanical and electronic characterization of a novel kind of scanning probe microscopy probe fabricated by the microwave plasma-enhanced chemical vapor deposition growth of carbon nanotubes using a catalytic palladium film deposited only near the apices of commercial tapping mode atomic force microscopy (AFM) cantilevers with the use of a newly developed controlled-area electroplating method. This process is shown to result in the growth of coaxial palladium nanowire/carbon nanotube composite structures (PdNWCNTs). The authors demonstrate that neither the cantilever quality factor nor the cantilever spring constant is significantly degraded by PdNWCNT growth, and show that PdNWCNT probes are adequate for standard tapping mode AFM imaging. Low resistance Ohmic contact between PdNWCNT probes and metal surfaces is demonstrated. Importantly, repeated surface contact and current flow is shown to not damage the PdNWCNTs, indicating that the probes are appropriate for multiprobe conductivity measurements. A brief overview of the fabrication process is also provided.
The extended Fourier pseudospectral time-domain method for atmospheric sound propagation
Authors: Hornikx Maarten , Waxler Roger , Forssén Jens
Published: October 2010

An extended Fourier pseudospectral time-domain (PSTD) method is presented to model atmospheric sound propagation by solving the linearized Euler equations. In this method, evaluation of spatial derivatives is based on an eigenfunction expansion. Evaluation on a spatial grid requires only two spatial points per wavelength. Time iteration is done using a low-storage optimized six-stage Runge-Kutta method. This method is applied to two-dimensional non-moving media models, one with screens and one for an urban canyon, with generally high accuracy in both amplitude and phase. For a moving atmosphere, accurate results have been obtained in models with both a uniform and a logarithmic wind velocity profile over a rigid ground surface and in the presence of a screen. The method has also been validated for three-dimensional sound propagation over a screen. For that application, the developed method is in the order of 100 times faster than the second-order-accurate FDTD solution to the linearized Euler equations. The method is found to be well suited for atmospheric sound propagation simulations where effects of complex meteorology and straight rigid boundary surfaces are to be investigated.
Advantage of bimodal fitting in prosody perception for children using a cochlear implant and a hearing aid
Authors: Straatman L. V. , Rietveld A. C. M. , Beijen J. , Mylanus E. A. M. , Mens L. H. M.
Published: October 2010

Cochlear implants are largely unable to encode voice pitch information, which hampers the perception of some prosodic cues, such as intonation. This study investigated whether children with a cochlear implant in one ear were better able to detect differences in intonation when a hearing aid was added in the other ear (“bimodal fitting”). Fourteen children with normal hearing and 19 children with bimodal fitting participated in two experiments. The first experiment assessed the just noticeable difference in F0, by presenting listeners with a naturally produced bisyllabic utterance with an artificially manipulated pitch accent. The second experiment assessed the ability to distinguish between questions and affirmations in Dutch words, again by using artificial manipulation of F0. For the implanted group, performance significantly improved in each experiment when the hearing aid was added. However, even with a hearing aid, the implanted group required exaggerated F0 excursions to perceive a pitch accent and to identify a question. These exaggerated excursions are close to the maximum excursions typically used by Dutch speakers. Nevertheless, the results of this study showed that compared to the implant only condition, bimodal fitting improved the perception of intonation.
Detection of modulation of a 4-kHz carrier
Authors: Viemeister Neal F. , Stellmack Mark A. , Byrne Andrew J.
Published: October 2010

To better understand the processing of complex high-frequency sounds, modulation-detection thresholds were measured for sinusoidal frequency modulation (SFM), quasi-frequency modulation (QFM), sinusoidal amplitude modulation (SAM), and random-phase FM (RPFM). At the lowest modulation frequency (5 Hz) modulation thresholds expressed as AM depth were similar for RPFM, SAM and QFM suggesting the predominance of envelope cues. At the higher modulation frequencies (20 and 40 Hz) thresholds expressed as total frequency excursions were similar for SFM and QFM suggesting a common mechanism, one perhaps based on single-channel FM-to-AM conversion or on a multi-channel place mechanism. The fact that the nominal envelopes of SFM and QFM are different (SFM has a flat envelope), seems to preclude processing based on the envelope of the external stimulus. Also, given the 4-kHz carrier and the similarity to previously published results obtained with a 1-kHz carrier, processing based on temporally-coded fine structure for all four types of modulation appears unlikely.
The effects of the addition of low-level, low-noise noise on the intelligibility of sentences processed to remove temporal envelope information
Authors: Hopkins Kathryn , Moore Brian C. J. , Stone Michael A.
Published: October 2010

The intelligibility of sentences processed to remove temporal envelope information, as far as possible, was assessed. Sentences were filtered into N analysis channels, and each channel signal was divided by its Hilbert envelope to remove envelope information but leave temporal fine structure (TFS) intact. Channel signals were combined to give TFS speech. The effect of adding low-level low-noise noise (LNN) to each channel signal before processing was assessed. The addition of LNN reduced the amplification of low-level signal portions that contained large excursions in instantaneous frequency, and improved the intelligibility of simple TFS speech sentences, but not more complex sentences. It also reduced the time needed to reach a stable level of performance. The recovery of envelope cues by peripheral auditory filtering was investigated by measuring the intelligibility of ‘recovered-envelope speech’, formed by filtering TFS speech with an array of simulated auditory filters, and using the envelopes at the output of these filters to modulate sinusoids with frequencies equal to the filter center frequencies (i.e., tone vocoding). The intelligibility of TFS speech and recovered-envelope speech fell as N increased, although TFS speech was still highly intelligible for values of N for which the intelligibility of recovered-envelope speech was low.
Analysis of the radiated information in spinning sound fields
Authors: Carley Michael
Published: October 2010

The information content of a spinning sound field is analyzed using a combination of exact and asymptotic results, in order to set limits on how accurately source identification can be carried out. Using a transformation of the circular source to an exactly equivalent set of line source modes, given by Chebyshev polynomials, it is found that the line source modes of order greater than the source wavenumber generate exponentially small fields. Asymptotic analysis shows that the remaining, lower order, modes radiate efficiently only into a region around the source plane, with this region shrinking as the mode order is increased. The results explain the ill-conditioning of source identification methods; the successful use of low order models in active noise control; and the low radiation efficiency of subsonic jets.
Stop-like modification of the dental fricative /ð/: An acoustic analysis
Authors: Zhao Sherry Y.
Published: October 2010

This study concentrates on one of the commonly occurring phonetic variations in English: the stop-like modification of the dental fricative /ð/. The variant exhibits a drastic change from the canonical /ð/; the manner of articulation is changed from one that is fricative to one that is stop-like. Furthermore, the place of articulation of stop-like /ð/ has been a point of uncertainty, leading to confusion between stop-like /ð/ and /d/. In this study, acoustic and spectral moment measures were taken from 100 stop-like /ð/ and 102 /d/ tokens produced by 59 male and 23 female speakers in the TIMIT corpus. Data analysis indicated that stop-like /ð/ is significantly different from /d/ in burst amplitude, burst spectrum shape, burst peak frequency, second formant at following-vowel onset, and spectral moments. Moreover, the acoustic differences from /d/ are consistent with those expected for a dental stop-like /ð/. Automatic classification experiments involving these acoustic measures suggested that they are salient in distinguishing stop-like /ð/ from /d/.
Learning to use an artificial visual cue in speech identification
Authors: Stephens Joseph D. W. , Holt Lori L.
Published: October 2010

Visual information from a speaker’s face profoundly influences auditory perception of speech. However, relatively little is known about the extent to which visual influences may depend on experience, and extent to which new sources of visual speech information can be incorporated in speech perception. In the current study, participants were trained on completely novel visual cues for phonetic categories. Participants learned to accurately identify phonetic categories based on novel visual cues. These newly-learned visual cues influenced identification responses to auditory speech stimuli, but not to the same extent as visual cues from a speaker’s face. The novel methods and results of the current study raise theoretical questions about the nature of information integration in speech perception, and open up possibilities for further research on learning in multimodal perception, which may have applications in improving speech comprehension among the hearing-impaired.
Wind turbines and bat mortality: Doppler shift profiles and ultrasonic bat-like pulse reflection from moving turbine blades
Authors: Long Chloe V. , Flint James A. , Lepper Paul A.
Published: October 2010

Bat mortality resulting from actual or near-collision with operational wind turbine rotors is a phenomenon that is widespread but not well understood. Because bats rely on information contained in high-frequency echoes to determine the nature and movement of a target, it is important to consider how ultrasonic pulses similar to those used by bats for echolocation may be interacting with operational turbine rotor blades. By assessing the characteristics of reflected ultrasonic echoes, moving turbine blades operating under low wind speed conditions (<6 m s−1) were found to produce distinct Doppler shift profiles at different angles to the rotor. Frequency shifts of up to ±700–800 Hz were produced, which may not be perceptible by some bat species. Monte Carlo simulation of bat-like sampling by echolocation revealed that over 50 rotor echoes could be required by species such as Pipistrellus pipistrellus for accurate interpretation of blade movement, which may not be achieved in the bat’s approach time-window. In summary, it was found that echoes returned from moving blades had features which could render them attractive to bats or which might make it difficult for the bat to accurately detect and locate blades in sufficient time to avoid a collision.
Efficient evaluation of edge diffraction integrals using the numerical method of steepest descent
Authors: Asheim Andreas , Svensson U. Peter
Published: October 2010

For the problem of edge diffraction from an edge of finite length a frequency-domain solution, obtained from an analytical time-domain solution, has been presented by Svensson et al. [Acta. Acust. Acust. 95, 568–572]. This formulation takes the form of a Fourier-type integral whose evaluation is expensive in the high frequency range. This paper demonstrates that by using tailored highly oscillatory quadrature methods based on asymptotic properties of the integral, accurate approximations in the high frequency case can be obtained with little computational effort.
Locating an acoustic point source scattered by a skull phantom via time reversal matched filtering
Authors: Sadler J. , Shapoori K. , Malyarenko E. , Severin F. , Maev R. Gr.
Published: October 2010

This paper examines the utilization of the time reversal matched filtering method to resolve the location of an acoustic point source beneath a skull phantom (variable thickness layer), without the removal of this layer. This acoustical process is examined experimentally in a water tank immersion system containing an acoustic source, a custom-made skull phantom, and a receiving transducer in a pitch-catch arrangement. The phantom is designed to approximately model the acoustic properties of an average human skull bone (minus the diploe layer), while the variable thickness of the phantom introduces a variable time delay to the acoustic wave, relative to its entry point on the phantom. This variable delay is measured and corrected for, and a matched filtering time reversed process is used to determine the location of the point source. The results of the experiment are examined for various positions of the acoustic source behind the phantom and compared to the reference cases with no phantom present. The average distance between these two cases is found to be 4.36 mm, and within the expected deviation in results due to not accounting for the effects of refraction.
On the limitation of a diffusion equation model for acoustic predictions of rooms with homogeneous dimensions
Authors: Escolano José , Navarro Juan M. , López José J.
Published: October 2010

In recent years a model for predicting sound fields in enclosures has been proposed, based on the mathematical theory of diffusion. This model is held to be valid for predicting the late reverberation component of the impulse response, on the basis that sufficient reflection events must occur [Valeau et al., J. Acoust. Soc. Am. 119, 1504–1513 (2006)]. The present work determines numerically the extent of reflections necessary for the solution of the diffusion equation model to be accurate in quasi-cubic rooms. Some preliminary numerical experiments have been carried out to determine after how many mean-free times of the impulse response, which is obtained by a geometrical-acoustic approach, gives a similar result to the solution obtained from a diffusion equation model.
Cochlea-scaled spectral entropy predicts rate-invariant intelligibility of temporally distorted sentences
Authors: Stilp Christian E. , Kiefte Michael , Alexander Joshua M. , Kluender Keith R.
Published: October 2010

Some evidence, mostly drawn from experiments using only a single moderate rate of speech, suggests that low-frequency amplitude modulations may be particularly important for intelligibility. Here, two experiments investigated intelligibility of temporally distorted sentences across a wide range of simulated speaking rates, and two metrics were used to predict results. Sentence intelligibility was assessed when successive segments of fixed duration were temporally reversed (exp. 1), and when sentences were processed through four third-octave-band filters, the outputs of which were desynchronized (exp. 2). For both experiments, intelligibility decreased with increasing distortion. However, in exp. 2, intelligibility recovered modestly with longer desynchronization. Across conditions, performances measured as a function of proportion of utterance distorted converged to a common function. Estimates of intelligibility derived from modulation transfer functions predict a substantial proportion of the variance in listeners’ responses in exp. 1, but fail to predict performance in exp. 2. By contrast, a metric of potential information, quantified as relative dissimilarity (change) between successive cochlear-scaled spectra, is introduced. This metric reliably predicts listeners’ intelligibility across the full range of speaking rates in both experiments. Results support an information-theoretic approach to speech perception and the significance of spectral change rather than physical units of time.
Sound speed profile characterization by the image source method
Authors: Pinson S. , Guillon L.
Published: October 2010

This paper presents the first results of an imaging technique that measures the geoacoustic structure of a seafloor in shallow water areas. The devices used were a broadband (100 Hz–6 kHz) acoustic source towed by a ship and a vertical array. Among all the acoustic paths existing in the water column, two are used: the direct one and the seabed-reflected one, the latter being composed of the reflections from the seafloor’s surface as well as that from each buried layer. Due to the good time resolution of the signal and to the short range configuration, the reflected signal can be modeled as a sum of contributions coming from image sources relative to the seabed layers. The seabed geometry and the sound speed profile can then be recovered with the detection and localization of these image sources. The map of the image sources is obtained by a function that combines back-propagation of signals and knowledge of the emitted pulse. The thickness and sound-speed of each layer is finally obtained by a position analysis of the image sources. The results obtained by this data-driven algorithm on both at-sea and synthetic data are satisfactory.
Solid-perforated panel layout optimization by topology optimization based on unified transfer matrix
Authors: Kim Yoon Jae , Kim Yoon Young
Published: October 2010

This paper presents a numerical method for the optimization of the sequencing of solid panels, perforated panels and air gaps and their respective thickness for maximizing sound transmission loss and/or absorption. For the optimization, a method based on the topology optimization formulation is proposed. It is difficult to employ only the commonly-used material interpolation technique because the involved layers exhibit fundamentally different acoustic behavior. Thus, an optimization method formulation using a so-called unified transfer matrix is newly proposed. The key idea is to form elements of the transfer matrix such that interpolated elements by the layer design variables can be those of air, perforated and solid panel layers. The problem related to the interpolation is addressed and bench mark-type problems such as sound transmission or absorption maximization problems are solved to check the efficiency of the developed method.
Spectral and synchrony differences in auditory brainstem responses evoked by chirps of varying durations
Authors: Petoe Matthew A. , Bradley Andrew P. , Wilson Wayne J.
Published: October 2010

The chirp-evoked ABR has been termed a more synchronous response, referring to the fact that rising-frequency chirp stimuli theoretically compensate for temporal dispersions down the basilar membrane. This compensation is made possible by delaying the higher frequency content of the stimulus until the lower frequency traveling waves are closer to the cochlea apex. However, it is not yet clear how sensitive this temporal compensation is to variation in the delay interval. This study analyzed chirp- and click-evoked ABRs at low intensity, using a variety of tools in the time, frequency, and phase domains, to measure synchrony in the response. Additionally, this study also examined the relationship between chirp sweep rate and response synchrony by varying the delay between high- and low-frequency portions of chirp stimuli. The results suggest that the chirp-evoked ABRs in this study exhibited more synchrony than the click-evoked ABRs and that slight gender-based differences exist in the synchrony of chirp-evoked ABRs. The study concludes that a tailoring of chirp parameters to gender may be beneficial in pathologies that severely affect neural synchrony, but that such a customization may not be necessary in routine clinical applications.
Unwanted sounds generated with test tone presentation can spoil extended high-frequency audiometry
Authors: Kurakata Kenji , Mizunami Tazu , Matsushita Kazuma , Shiraishi Kimio
Published: October 2010

Unwanted sounds from a commercially available audiometer were evaluated in terms of their effects on extended high-frequency (EHF) audiometry. Although the manufacturer reported that the audiometer conformed to relevant International Electrotechnical Commission (IEC) standards, the audiograms obtained using the audiometer were erroneous because the subjects had responded falsely to noise generated with the test tone presentation before detecting the test tone. Analyses of acoustic and electric output signals revealed that the audiometer generated most of the unwanted sounds, not the earphones that were used. Based on the measurement results, clinical implications of the measurement results are discussed for conducting more reliable EHF audiometry.
Short-term adaptation to accented English by younger and older adults
Authors: Gordon-Salant Sandra , Yeni-Komshian Grace H. , Fitzgibbons Peter J. , Schurman Jaclyn
Published: October 2010

This study examined the effects of age and hearing loss on short-term adaptation to accented speech. Data from younger and older listeners in a prior investigation [Gordon-Salant et al. (2010). J. Acoust. Soc. Am. 128, 444–455] were re-analyzed to examine changes in recognition over four administrations of equivalent lists of English stimuli recorded by native speakers of Spanish and English. Results showed improvement in recognition scores over four list administrations for the accented stimuli but not for the native English stimuli. Group effects emerged but were not involved in any interactions, suggesting that short-term adaptation to accented speech is preserved with aging and with hearing loss.
From school to individuals: How detailed tridimensional observations using multibeam sonar have changed our understanding on the role of fish schools.
Authors: Gerlotto Francois
Published: October 2010

Multibeam sonars have been used since the 1990s for tridimensional observations of fish schools. Using these tools, a very detailed description of external and internal structure and dynamics of groups and individuals inside pelagic schools has been given. From these results, a series of hypotheses are drawn: (1) Schools are adapting their morphologies to their surroundings. Thus typologies represent a mixture of specific organization and adaptations to the ecosystem. (2) The internal organization of fish inside a school presents several scales, from the global structure of the school to micro-structures of a few individuals. These intricate structures allow the school to answer rapidly to any perturbation of the environment. They are tools for communication inside the school and allow fast exchanges of information. (3) The observation of small scale structures inside a school changed our understanding on school functioning. Individuals are not necessarily anonymous inside a school and may establish relationships between familiar, leading to groups that may last longer than the school itself. In synthesis, a school is a complex organization on non-necessarily anonymous individuals that presents a series of adapted 3-D structures allowing fast and precise reactions to the surroundings and facilitating adaptation to environmental conditions.
Scaling of viscoelastic shell properties of lipid encapsulated microbubbles with frequency.
Authors: Huo Emma , Helfield Brandon , Goertz David
Published: October 2010

While it has been established that nonlinear oscillations of lipid encapsulated microbubbles occur at frequencies of >10 MHz, the understanding of bubble behavior in this frequency range is limited and is not predicted by bubble models using shell properties derived at <5 MHz. Here we investigate the scaling of the viscoelastic shell properties of lipid encapsulated contrast agents with frequency and bubble size. Attenuation measurements were performed over 2–30 MHz and, using size distribution measurements and the linearized Rayleigh–Plesset equation, shell elasticity and viscosity terms were estimated. Experiments were performed on a series of narrow size distribution in-house agents with progressively smaller diameters, as well as the high frequency agent Micromarker. In-house agents peaked in attenuation at 4.2, 8.5, 13, and 22 MHz, and Micromarker rose until 21 MHz. The elasticity for in-house agents was comparable to other agents at lower frequencies, while the viscosity rapidly decreased above 10 MHz. For Micromarker, which has a different fabrication process, the elasticity was substantially higher than the in-house agent and over 15–30 MHz its viscosity was far lower viscosity than those reported at lower frequencies. The use of low shell viscosities in bubble models enables the prediction of nonlinear oscillations at higher frequencies.
Generalization of the iterative nonlinear contrast source method to realistic, nonlinear biomedical tissue.
Authors: Verweij Martin D. , Huijssen Jacob , Demi Libertario , van Dongen Koen W. A. , de Jong Nico
Published: October 2010

Originally, the iterative nonlinear contrast source (INCS) method has been developed to compute the nonlinear, wide-angle, pulsed ultrasound field in a homogeneous and lossless medium. The method considers the nonlinear term of the lossless Westervelt equation as a distributed contrast source in a linear background medium. The full nonlinear wave field follows from the Neumann iterative solution of the resulting integral equation. Each iteration step involves the spatiotemporal convolution of the background Green’s function with an estimate of the contrast source. Appropriate filtering provides accurate field predictions for a discretization approaching two points per smallest wavelength or period. The current paper first discusses the theoretical generalization of the original contrast source approach, e.g., to include tissue attenuation or inhomogeneity. Next, computational results are presented that show the directional independence (even for the nonlinear distortion) and the wide-angle performance of the original INCS method. Finally, results are presented for extensions that can deal with power law losses or inhomogeneity in the wave speed. The wide-angle capability and the versatility of the contrast source approach demonstrate that the INCS method is well-suited for modeling the various aspects of realistic biomedical tissue behavior. [Work supported by STW and NCF.]
Discrimination of MP3-compressed musical instrument tones.
Authors: Lee Chung , Horner Andrew
Published: October 2010

Eight musical instrument tones were compressed using an MP3 codec to determine how the detection of compressed sounds varies with bit-rate and instrument. Sounds with harmonically flattened frequencies were compressed with bit-rates of 32, 40, 48, 56, 64, 80, 96, 112, 128, and 160 kbps. Listeners were asked to discriminate the compressed sounds from the original sounds. Averaged over the eight instruments, discrimination was very good (above 80%) for bit-rates of 32 and 40 kbps, moderate (above 70%) for 48 and 56 kbps, and poor (around 50–60%) for bit-rates above 64 kbps. Statistical analysis showed that discrimination was significantly affected by the instrument for intermediate bit-rates of 40, 48, 56, and 80 kbps. Discrimination scores were strongly correlated with the signal-to-mask ratio and spectral irregularity of the original tone. Relative spectral error as a predictor for discrimination accounted for more than 80% of the variance in the discrimination scores.