bluuebunny/crossref_metadata_2025 huggingface dataset:
The phonotactic influence on the perception of a consonant cluster /pt/ by native-English and native-Polish listeners: A behavioral and ERP study.
Authors: Wagner Monica , Shafer Valerie L.
Published: October 2013

The perception of the cluster /pt/ in word onset in native-Polish and native-English adult listeners was compared using behavioral and event-related potential (ERP) measures to explore the language-specific phonotactic influence on speech perception. Acoustic-phonetic features of phonemes vary with context and phonotactic rules specify all allowable phoneme contexts. Both native-Polish and native-English groups are exposed to the cluster /pt/ in their language but only one group, native-Polish, experience the cluster in the context examined, word onset. Word onset consonant cluster /st/ is used as a control. Participants were asked to determine whether they heard the second word of a pair as consisting of two syllables or three (e.g., pteva versus peteva). Behavioral results revealed that Polish listeners perceive the /pt/ cluster with greater accuracy than English listeners. ERPs revealed late components that differ for the two language groups reflecting linguistically-relevant aspects of the /pt/ contrast and early components that are essentially the same in the two language groups reflecting physical-acoustic differences. ERP results suggest the /st/ contrast to be more salient than the /pt/ contrast consistent with the higher behavioral accuracy for the /st/ cluster. These findings support the suggestion that psychoacoustic salience of acoustic-phonetic features influences speech perception.
Asymmetric development of perception and production of lexical stress in Korean second-language (L2) learners of English.
Authors: Shin Jeonghwa , Speer Shari R.
Published: October 2013

This study explores perception and production of lexical stress information in L2 English learners whose L1 employs a fixed rhythmic pattern at the lexical level. Nineteen English L1 speakers and 14 Korean L2 learners of English were trained to learn 16 minimal stress nonword pairs with picture referents which are segmentally disambiguating in the last syllable (/dȝákunaɪ/ vs /dȝakúnɚ/). The eye-tracking perception experiment revealed that English L1 speakers exploited lexical stress information of the first two syllables to spot the target word in the instruction, “Click on the (target word),” whereas Korean L2 learners’ identification of the target word was delayed until the last syllable. In their production of words in a carrier, “This is the (target word),” however, L2 learners used loudness and durational cue to indicate alternative prominence of the first two syllable as did English L1 speakers. These results imply the development of production and processing of lexical stress in L2 word learning can be asymmetrical. This asymmetry is attributable to the L1 which has a fixed (T)HLH accentual phrase pattern at the lexical level and thus provides little incentive for the lexically specified stress processing. [Work supported by Linguistics Dept., Ohio State University.]
Role of rhythmic and intonational cues in language discrimination.
Authors: Vicenik Chad , Sundara Megha
Published: October 2013

Languages differ in rhythm as well as intonation. Research indicates that adult listeners are able to use rhythm to discriminate between two languages from different rhythm classes [Ramus Mehler, (1999)]. For languages within the same rhythm class, adults are able to use to use intonation to discriminate between languages like English and Dutch, but only when one of the languages is familiar [Ramus and Mehler, (1999); Pijper, (1983)]. It remains unclear if the rhythmic differences between languages in the same rhythm class are enough to support language discrimination. In this paper, we tested American English listeners’ ability to categorize re-synthesized American English and German sentences or American and Australian English sentences from which all segmental information had been removed. English and German are from the same rhythm class and differ in intonation; whereas American and Australian English can be thought to be rhythmically identical, but differ in intonation. Subjects were tested in three conditions: (a) with only intonational cues; (b) with only rhythmic cues; and (c) both intonational and rhythmic cues. Preliminary results indicate that listeners rely on rhythm, but not intonation, to distinguish between English and German, and only on intonation to distinguish between American and Australian English.
Semantic contextual cues and listener adaptation to foreign-accented English.
Authors: Piccinini Page , Bradlow Ann
Published: October 2013

The context surrounding words can facilitate word recognition for native and non-native listeners. However, for degraded speech signals, (e.g., with noise), non-natives may lose the ability to take advantage of contextual cues unless the speech is clearly produced [Bradlow and Alexander (2007)]. This study investigated whether: (1) foreign-accented speech degrades the signal such that natives show reduced ability to take advantage of context, and (2) both native and non-native listeners adapt to foreign-accented speech. Native and non-native listeners were exposed to accented speech in two blocks. In each block, half the sentence final words were in high and half were in low predictability contexts. Listeners were asked to identify sentence final words. In a single talker condition, natives benefited from context and adapted to the accent; non-natives could not use context but showed adaption. In a multitalker condition, natives neither benefited from context nor adapted to the accent. Non-natives benefited from context and adapted; however, the context effect was only seen when listener and speaker L1 matched. These results suggest that accented speech disrupts the native ability to take advantage of context, but this can be overcome by adaptation to the speaker. Non-natives benefit substantially from a talker-listener L1 match.
Time-course of perception of Mandarin Chinese tones.
Authors: Chang Chiung-Yun , Fox Robert Allen
Published: October 2013

The current study examines the effects of dialect variation on the time-course of lexical tone identification by native and non-native listeners of Mandarin Chinese. Listeners were asked to identify the tone of an isolated Chinese word presented without a precursor phrase. All stimuli were exemplars of V, CV, or CVC combinations that represented real words in Mandarin when produced with any of the four possible lexical tones. Words were produced by multiple talkers with a wide range of F0 values. The dialect of the talkers was also systematically varied. Half were native speakers of Beijing Mandarin, and the other half were native speakers of Taiwanese Mandarin. Preliminary acoustic analysis showed significant differences in tonal realization of the four lexical tones, especially Tone 3. There were three groups of listeners: native speakers of Beijing Mandarin and Taiwanese Mandarin and native English speakers who were learning Beijing Mandarin. A gating task was utilized to determine the temporal location in the token when the lexcial tone was correctly identified and to examine the nature (and time course) of tone confusions. Results will be discussed in terms of the effects of dialect and F0 variation of the stimuli and the native language of the listener.
Increased second-language vocabulary size is associated with more consistent second-language vowel categorization and better discrimination.
Authors: Bundgaard-Nielsen Rikke L. , Best Catherine T. , Tyler Michael D.
Published: October 2013

Improvement in second-language (L2) perception has been posited to asymptote early in L2 learning when the L2 vocabulary is still small, whereas a large L2 vocabulary curtails perceptual learning [PAM-L2: Best and Tyler (2007)]. We extend this proposition by suggesting that early L2 lexical development facilitates establishment of phonological categories in a manner analogous to toddlers’ L1 acquisition before versus after the vocabulary explosion. According to this revised view, L2 speech should be assimilated more consistently to phonological categories, and cross-boundary contrasts discriminated more accurately, by learners with large versus small L2 vocabularies. We applied a novel whole-system approach to evaluate perception of L2 vowels with respect to the L1 vowel system. Japanese learners of Australian English with under 12 weeks of L2 immersion completed labeling and goodness ratings on all Australian vowels, using all mono- and bi-moraic Japanese vowels and vowel combinations. They also completed discrimination tasks on four L2 vowel contrasts, representing a range of PAM-L2 contrast types, and a L2 vocabulary size assessment. Learners with larger vocabularies had more consistent vowel assimilation and more accurate cross-boundary discrimination than those with smaller vocabularies, supporting the proposition that lexical development supports L2 phonological acquisition. [Work supported by NIH and MARCS/UWS.]
Perception of foreign accent in Japanese and Brazilian Portuguese: Prosodic and segmental factors.
Authors: Komatsu Masahiko
Published: October 2013

Japanese sentences read by Japanese-descent Brazilians (L2) and native Japanese speakers (L1) were rated by native Japanese speakers, and Portuguese sentences read by native Japanese speakers learning Portuguese (L2) and Japanese-descent Brazilians (L1) were rated by Brazilians. The raters evaluated three types of samples: (a) sounds without spectral properties (representing prosodic features); (b) F0-flattened sounds (representing segmental features); and (c) unmodified sounds. In both languages, the perceptual scores of L1 and L2 samples were separated most clearly in (c), followed by (b) and (a). Both the scores of (a) and (b) showed strong correlations with (c) in L2. These suggest that both prosodic and segmental features play a role in the detection of foreign accent, but the latter has a greater effect. F0 characteristics varied between speaker groups rather than languages. The speaking rate in L2 was correlated with the perception scores. The effect of segmental features was greater in L2 Portuguese than in L2 Japanese, i.e., greater in less fluent speech. Foreign accents in both languages share common properties although having some differences. [This work is the revised version of Komatsu and Kimoto (2008) and Komatsu (in press), and partially supported by KAKENHI (20242010) and HSUH Kotaisa grant.]
Effects of native language and amount of experience on crosslinguistic perception.
Authors: Cebrian Juli
Published: October 2013

Models of second language (L2) speech learning draw on the notion of perceptual similarity to make predictions about L2 perception and production difficulty. Crosslinguistic perceived similarity is commonly assessed by means of perceptual assimilation tasks involving identification of target stimuli and goodness of fit ratings. Further, experience with an L2 may affect the perception of not only target language vowels but also native vowels. This paper reports the results of a crosslinguistic perception study involving English and Catalan vowels and diphthongs. The study assessed the perceived similarity of the two vowel systems by testing native speakers of each language on sounds from both their native language and the foreign language. Vowels were presented in CVC syllables. The effect of learning a second language was investigated by comparing the performance of language learners and monolingual speakers on the same task. The comparison between the two monolingual groups indicated a symmetry in the pattern of crosslinguistic perceived similarity while the effect of experience was found to vary with different vowels. The results are discussed in light of current theories and their predictions for second language perception and production. [Work supported by Grants HUM2005-02746/FILO (Spanish Ministry of Education) and 2005SGR00864 (Catalan Government).]
Adapting second language phonemic perception training to common instructional situations: Pitfalls and progress.
Authors: Sawallis Thomas R. , Townley Michael W.
Published: October 2013

Adult language learners improve both perception and production of difficult target language phonemic contrasts through high variability phonetic training (HVPT) on minimal pairs. This training entails two alternative forced choice identifications with feedback of a corpus encompassing multiple talkers, tokens, and phonological contexts. This technique, refined most notably by Pisoni and colleagues [Bradlow et al. (1999)], has been little used in real pedagogical situations, due partly to inconvenient protocols (e.g., 1 h, 3 days per week, for 3 weeks) and partly to the difficulty of developing a robust presentation routine attractive to students. We have attacked these problems, and after two semesters of pilot work refining the training presentation (of English /r-l/ to Japanese, Korean, and Chinese native learners), we expect this semester to have students who receive a full complement of training at ∼15 min, 2–3 days per week, throughout the term. Results will be presented and compared with previous research, and we will discuss some of the difficulties (technological, practical, and especially social) that were overcome for the sake naturalistic pedagogical application.
Korean-English bilinguals’ perception of phonetic contrasts in their two languages.
Authors: Maye Jessica , Luque Jenna , Farmer Thomas , Lee Yubin , Kim Midam
Published: October 2013

Korean speakers are known to find English /r/-/l/ difficult to discriminate, and English speakers have trouble discriminating Korean voicing contrasts. We tested Korean-English bilinguals’ perception of these difficult phonetic contrasts to examine the effects of age of acquisition and language dominance on bilinguals’ perception in their two languages. All bilingual participants were native Korean speakers but varied in age of English acquisition. Some reported English to be their dominant language, while others were Korean-dominant. Participants completed a 2AFC task in which they were asked to click on one out of a pair of pictures. On key trials the pictures formed a minimal pair (e.g., rock versus lock). The same task was completed once in English (key items contained the /r/-/l/ contrast) and once in Korean (key items contained the plain versus tense voicing contrast). Earlier exposure to English led to greater accuracy and faster response on the English task. However, neither age of acquisition nor language dominance affected performance on the Korean task. These results suggest that earlier exposure to a second language improves perception in that language, but that loss of dominance in a first language does not impair phonetic processing of that language. [Work supported by NIH#1R03HD048538 to JM.]
Looking back to see where we’re going.
Authors: Jenkins James
Published: October 2013

A brief sketch of the origins of the field of cross-language speech perception will be presented. This will be followed by comments on the current state of research as reflected in the workshop and suggestions as to future directions.
The penetration of sound into an extended reaction ground due to an arbitrarily oriented dipole.
Authors: Li Kai Ming , Liu Sheng
Published: October 2013

An asymptotic solution is derived for the sound fields below an extended reaction ground due to an arbitrarily oriented dipole placed near the air/ground interface. The derived approximate solutions are compared with accurate numerical schemes based on the fast field formulation and the direct numerical integration of the Fourier integral. It has been shown that the sound field above the ground can be computed accurately by using the concept of effective impedance [K. M. Li et al., J. Acoust. Soc. Am. 104, 679–685 (1998)]. The effective impedance approach is used to derive the asymptotic formula for predicting the penetration of sound into the extended reaction ground. However, there are apparent discrepancies in the predicted sound fields according to the analytical solution and the accurate numerical schemes. A modified analytical formula is then developed that leads to more accurate numerical results. The resulting analytical formula due to an airborne acoustic excitation may be used as a basis for a future study to compute the particle displacements induced by an elastic object buried in a rigid-frame porous medium.
Individual differences in the perception of final consonant voicing among native and non-native speakers of English.
Authors: Smith Bruce L. , Hayes-Harb Rachel
Published: October 2013

Various studies have provided modest evidence supporting the ideas: (1) that non-native listeners outperform native listeners in judging productions by other non-native speakers with whom they share a first-language (L1) background and (2) that non-native listeners are more accurate judging productions by subjects with whom they share an L1 background than they are judging speech contrasts of native English speakers. Research regarding these issues has typically been based on group findings, so it is not clear to what extent these tendencies may occur among individual listeners. The present investigation reports findings for 15 native English (NE) listeners and 15 non-native listeners (native Mandarin: NM), who made judgments about English voiced/voiceless minimal pairs produced by six other NE and six other NM talkers. When listening to the six NM talkers, fewer than half of the 15 NM subjects performed better than the range shown by the 15 NE listeners. Further, the 15 NM listeners were more accurate than the 15 NE listeners in judging the voicing contrast for just two of the six NM speakers. Thus, limited evidence was found that individual, non-native subjects demonstrate patterns that might have been expected on the basis of previous group findings.
Density and soundspeed measurements of various Bering Sea zooplankton.
Authors: Warren Joseph D. , Smith Joy N. , Ressler Patrick H.
Published: October 2013

Walleye pollock is a commercially and ecologically important species in the Bering Sea. Assessment of pollock stocks is conducted regularly using a combination of trawl net sampling and multiple frequency active acoustic echosounder surveys. In addition to backscatter from the species of interest, other marine life including several types of zooplankton and nekton can contribute substantial amounts of acoustic backscatter energy which can provide information regarding the abundance and distribution of these animals as well. Acoustic scattering models are used to estimate both the amount and frequency response of the acoustic energy scattered by the zooplankton, but these models require knowledge of various properties that describe the acoustically important characteristics of the zooplankton. We collected live zooplankton from the Bering Sea during June and July 2008. The morphology (spatial dimensions) and material properties (density and sound speed) of individual and groups of zooplankton (and some nekton) were measured. The taxa studied included euphausiids (Thysanoessa raschii, Thysanoessa inermis, Thysanoessa spinifera), copepods (Neocalanus sp.), amphipods (Themisto sp.), gastropod (Clione sp.), siphonophores, jellyfish, and squid. The results of our measurements with regard to acoustic scattering model development and use will also be discussed.
Realities of publishing in a journal: Why should you submit, what should you submit, and what problems might you encounter?
Authors: Pierce Allan D.
Published: October 2013

Attractions of a journal are its widespread availability, its archival (forever!) nature, its priority in literature searches, and its prestige. Articles should be readable to others in the field, be significant, and original. JASA is selective and imposes standards. Perceived quality is often measured by the “impact factor,” which may have very little to do with the extent to which the journal fulfills the mission of the Society. Of great frustration to the editors is that a substantial fraction of authors who submit papers seem to be somewhat clueless as to what is a reasonable topic and what is a reasonable scope for an article in JASA. Frustrating also is that most good work reported at Society meetings never gets submitted. The present talk critically discusses the selection process, its peer-review aspects, and its flaws. The selection process deals with realities, such as that willing and competent reviewers are hard to find and that submitted reviews are often inane, with carefully selected highly expert associate editors who can make authoritative decisions without absolute reliance on external reviews. Suggestions are given on how to prepare a suitable manuscript and on how to cope with the vagaries of the peer-review process.
Intrinsic damping models and their role in predicting structural response.
Authors: Pierce Allan D. , Akay Adnan
Published: October 2013

In many industries, it is often desired to estimate whether a structure can withstand severe broad-band high-frequency loads. Because the structures have many natural frequencies within the band of interest, the response is critically affected by the damping within the structure. One typically performs finite element model computations with the elastic modulus replaced by a complex number, the ratio of imaginary to real parts being the loss factor, this taken as frequency independent. The crudity of such a model invariably leads to designs that are either overly conservative or not inspiring confidence. The present paper revisits the topic of internal damping from a fundamental standpoint and adopts the viewpoints of [J. J. Thomson (1888), Clarence Zener (1948)], in which “all anelastic phenomena are regarded as the superposition of elementary processes in which the stress relaxes exponentially.” The resulting general model involves a continuous distribution over relaxation times. Lumped parameter realizations require that the configuration of the structure be described by the positions of all the mass points, and also by those of a large number of “hidden variables” connected to the mass points by Maxwell elements (spring and dashpot is series). General implications of the model are derived and explained.
Monaural envelope correlation perception and broadband temporal analysis.
Authors: Hall Joseph W. , Buss Emily , Grose John H.
Published: October 2013

Monaural envelope correlation perception [V. M. Richards, J. Acoust. Soc. Am. 82, 1621–1630 (1987)] is a paradigm that reflects sensitivity to the correlation between the temporal envelopes of carriers that are separated in frequency. Previous experiments investigating this paradigm have employed narrowband noise stimuli, presumably because of a desire to ensure that the temporal envelopes of the bands are faithfully represented at the outputs of frequency selective auditory filters. Although wide comodulated bands can be generated, a reasonable expectation is that the representations of the bands at the outputs of auditory filters corresponding to their center frequencies would have substantially reduced comodulation, partly due to the fact that the absolute width of the auditory filter increases with increasing stimulus frequency. Our preliminary data nevertheless indicate robust sensitivity to envelope correlation for noise bandwidths that greatly exceed the bandwidths of peripheral filters. This sensitivity persists even when manipulations are employed that should interfere with the ability to use spectral profile cues or cues based upon envelope comparisons across subsets of auditory filters. Results will be discussed in terms of cues supporting envelope correlation perception with stimuli that are broad with respect to auditory filters. [Work supported by NIDCD 5R01DC000418.]
What do cognitive models and human judgments suggest about the desired structure of automatic classifiers?
Authors: Summers Jason E. , Gaumond Charles F. , Jemmott Colin W. , Brock Derek
Published: October 2013

Past studies probed human listeners’ efficacy at classification of impulsive sonar echoes by using paired-comparison ratings to measure perceptual dissimilarity. Interpreting these ratings requires a cognitive model comprising both a representation of the stimuli and a process operating on that representation. Initially, perceived dissimilarities were represented as distances in Euclidean space via multidimensional scaling. This assumed a continuous and spatial cognitive representation and proved difficult to relate to a linear vector space of features. Later work by the authors suggested a discrete (categorical) cognitive representation may better reflect perception of these stimuli. While similarity-based classifiers can bypasses feature extraction [S. Philips and J. Pitton, J. Acoust. Soc. Am. 123, 3344 (2008) (A)], the form of the similarity measure reflects the assumed cognitive representation [L. Cazzanti and M. R. Gupta, Proc. IEEE Intl. Symposium Info. Theory, pp. 1836–1849 (2006)]. Here, findings based on paired-comparison ratings and verbal descriptions of stimuli are discussed in terms of the cognitive models they reflect and implications for classifier architecture: the form of similarity measures, whether features are continuous or discrete, and whether features are common to all classes. [Work supported by the Office of Naval Research.]
Experimental active source ocean acoustic interferometry.
Authors: Brooks Laura A. , Gerstoft Peter
Published: October 2013

Green’s function approximation via ocean noise cross-correlation, referred to here as ocean acoustic interferometry, has previously been demonstrated experimentally for passive noise sources. Active sources offer the advantages of higher frequencies, controllability, and continuous monitoring. Experimental ocean acoustic interferometry is described here for two active source configurations: a source lowered vertically, and one towed horizontally. Results are compared and contrasted with cross correlations of passive noise. The results, in particular differences between the empirical Green’s function estimates and simulated Green’s functions, are explained with reference to theory and simulations. Approximation of direct paths is shown to be consistently good for each source configuration. Secondary (surface reflection) paths are shown to be more accurate for hydrophones with a greater horizontal separation. [Work supported by the Office of Naval Research under Grant No. N00014-05-1-0264.]
Three-dimensional source tracking in an uncertain environment via focalization.
Authors: Tollefsen Dag , Dosso Stan E.
Published: October 2013

This paper develops an approach to three-dimensional source tracking in an uncertain ocean environment using a horizontal line array (HLA). The tracking algorithm combines matched-field focalization for environmental (seabed and water column) and source-bearing model parameters with the VITERBI algorithm for range-depth estimation, and includes physical constraints on source velocity. The ability to track a source despite environmental uncertainty is examined using synthetic test cases for various track geometries and with varying degrees of prior information for environmental parameters. Performance is evaluated for a range of signal-to-noise ratios in terms of the probability of estimating a track within acceptable position/depth errors. The algorithm substantially outperforms tracking with poor environmental estimates, and generally obtains results close to those obtained with exact environmental knowledge. The approach is also applied to measured narrowband data recorded on a bottom-moored HLA in shallow water (the Barents Sea) and shown to successfully track both a towed submerged source and a surface ship in cases where simpler tracking algorithms failed.
Scattering prediction and measurement in architectural acoustics.
Authors: Bradley David T.
Published: October 2013

Reflected sound energy typically exhibits a combination of both specular and diffuse behavior when acoustic waves encounter a solid surface. For specularly reflected sound, the angle of reflection is equal to the angle of incidence. A diffusely reflected sound is characterized by dispersion in both the spatial and temporal domains. The ability of a surface to diffusely reflect sound is characterized by the amount of scattering in its reflected energy, and can be determined using numerical prediction schemes and experimental measurement techniques. Although the study of scattering surfaces plays an integral role in several fields of acoustics, the development of these measurement and prediction procedures is relatively nascent, particularly in the field of architectural acoustics. An overview of the current state-of-the-art for these procedures will be presented along with an outline of possible future directions in this area of research.
Sound production and behavior in an eastern North Pacific killer whale population: Implications for autonomous remote monitoring.
Authors: Holt Marla M. , Noren Dawn P. , Emmons Candice K. , Seibert Anna-Maria
Published: October 2013

Remote acoustic monitoring is often used to determine the seasonal and spatial distributions of vocal animals, particularly when conditions of other monitoring approaches are limited. Additionally, sound production patterns might be used to infer important activities of free-ranging animals in the absence of other cues. Animals produce sounds during activities such as foraging and breeding, but such patterns are expected to vary between species/populations that are based on a variety of ecological factors. For example, fish-eating killer whales are more vocally active than mammal-eating killer whales, presumably since mammalian prey are sensitive to killer whale sounds. Southern Resident killer whales (SRKWs) are a fish-eating population found in coastal waters of Washington State and British Columbia. The goal of this study was to extend previous work on the behavioral correlates of sound production in SRKWs. We collected behavioral and acoustic data simultaneously over two field seasons and found that click occurrence as well as calling rates (calls/whale/min) were significantly higher when whales were foraging compared to traveling. Such patterns are useful for inferring events from remote acoustic monitoring. These results also indicate that communicative signals are particularly important during foraging activities in this population and have implications for noise disturbance.
Tracking fish in a school using a broadband split-beam system.
Authors: Ito Masanori , Matsuo Ikuo , Imaizumi Tomohito , Akamatsu Tomonari , Nishimori Yasushi
Published: October 2013

Split-beam echo-sounder has been an important tool to understand fish behaviors undersea. In the split-beam system, each position of these fishes in three-dimensional space was estimated from delays of echoes and differences of delays between receive channels. To estimate the positions with high spatial resolution, the split-beam system which can emit and receive the broadband signals was constructed. However, in the case of a school of fish, it is difficult to determine accurately delay times of these fish because the echoes are overlapped with one another. To solve this problem, the new method was proposed to estimate delay times of fish by using the onset information of echoes, that is, extracting the steep temporal changes of the envelope pattern computed from the echo waveform. In a water tank experiment, it is examined that a location of a sphere can be accurately estimated by using the proposed method. In the sea, the echoes from schools of fish were measured with this system. It is examined that each location of fish in the three-dimensional space can be estimated and the numbers of fish can be counted. The tracks of the fish can be computed by changes of the fish locations along pings.
A transfer matrix method for estimating the dispersion and attenuation of plane waves in the standing wave tube.
Authors: Hou Kang , Bolton J. Stuart
Published: October 2013

In this paper, an iterative method based on the transfer matrix approach is described for evaluating the sound speed and attenuation constant of air in a standing wave tube. The procedure is based on transfer matrix, the four-microphone method for measuring the transmission loss of acoustical materials. In the latter procedure, a sample is placed between two pairs of microphones, where the sample is exposed to an incident plane wave field. In the present case, the air inside the standing wave tube is treated as the sampled material. Since the knowledge of the dispersion characteristics of plane waves within the tube is required to perform this measurement, an iterative method must be applied at the postprocessing step to estimate the complex wave numbers in the sample section. The result from the experiments showed that the air temperature within the tube has a significant impact on the results. The measured results were found to be in good agreement with the Temkin formula for attenuation in tubes. In addition, the approach may be extended to the accurate measurement of viscosity and sound velocity of liquids and gases.
Observation of channel pulse responses at long ranges in the Florida Straits.
Authors: DeFerrari Harry A. , Saintval Wendy , Wylie Jennifer
Published: October 2013

Acoustic propagation in shallow water is observed for transmission between a towed source (250 Hz m-sequence) and a bottom mounted horizontal array. A total signal processing gain of 45 dB results; 24 dB from m-sequence pulse compression and 21 dB from array gain. The tow is out to 60 km along a path parallel to shore. Individual and separable pulse arrivals associated with single normal modes of propagation are resolved in a parameter space of intensity, arrival time, out-of-plane angle of arrival, and Doppler. Two distinct groups of arrivals are observed, direct paths with near zero horizontal arrival angle and curved inshore, out-of-plane, paths with arrival angle of about 17 deg. A typical inshore path makes several bottom bounces both up and then down the sloping bathymetry. The inshore paths have more favorable transmission (less loss) and, at long ranges, exhibit a peculiar decrease in travel time with an increase in range. At short ranges “down” Doppler is observed, consistent with the opening range of the towed source, but at the longer ranges, “up” Doppler or closing range is observed even though the source is moving away from the receiver. A 3-D PE propagation model is applied to explain observations.
Ultrasonic upward FM vocalization of Mongolian gerbils, Meriones unguiculatus.
Authors: Nishiyama Kohei , Kobayasi Kohta , Riquimaroux Hiroshi
Published: October 2013

Mongolian gerbils, Meriones unguiculatus, have been used for auditory physiological studies. However, few studies have investigated precise relationships between a specific vocalization and a specific behavior. The purpose of this study was to examine the process to produce a specific vocalization: Greeting call. Their vocalizations and behaviors were separately recorded when two gerbils are put in the same experimental chamber. The sound data were synchronized with movie data to analyze their move-ment loci by using behavioral analysis software. The results showed that gerbils tended to emit ultrasonic upward FM calls, Greeting calls (average frequency range: 29.4 to 34.9 kHz, duration: 27.0 ms, n= 1185 calls), when the distance between two gerbils was close. About 45% of the calls were emitted when the distance was less than 10 cm. Moreover, in the situation where one gerbil quickly approached to the other, timings of Greeting call emission and footsteps of the approaching gerbil appeared to be synchronized. However, they did not vocalize at all when they were isolated, even when they moved in the same way. We may conclude that the repetitive upward FM ultrasonic emissions were not by-products of their movements but for their communication. [Research supported by ONR grant.]
Temporal processing as a function of age: Interaural time difference discrimination.
Authors: Grose John H. , Mamo Sara K. , Buss Emily , Hall Joseph W.
Published: October 2013

Older listeners often exhibit auditory temporal processing deficits. This study tested for temporal deficits in presenescent hearing. Three age groups participated: younger (18–28 yr); middle-aged (40–55 yr); older (63–75 yr). All had normal lower frequency hearing (thresholds ⩽ 20 dB HL, 250–2000 Hz). Exp. 1 measured ITD discrimination for tone frequencies from 250–1500 Hz (65 dB SPL). Stimuli were two 100-ms tone pulses (75-ms rise, 25-ms fall). The pulses were diotic in the standard stimulus; the signal had an ITD (random lead/lag) imposed on the trailing tone pulse. Older listeners generally had higher ITD thresholds than Younger listeners. Middle-aged and Younger listeners performed similarly at low frequencies but the middle-aged tended to hit ceiling (ȥ radians) at lower frequencies. Exp. 2 measured discrimination of So and Sτ signals as a function of frequency. Stimuli were tonal carriers modulated at 5 Hz (4 periods). Standard AM tones were diotic; signal tones alternated between So and Sȥ during successive modulator periods. Middle-aged listeners often performed slightly poorer than younger listeners, but better than older listeners. These results suggest that temporal processing deficits are evident in the pre-senescent auditory system. [Work supported by NIDCD 5-R01-DC01507.]
Perception or production? Training effects on cross-language phonological awareness tasks in Mandarin-speaking children.
Authors: Chiang Pi-Yu , Rvachew Susan
Published: October 2013

This study investigated training effects of perception-based and production-based English activities on the acquisition of phonological awareness of English sound structures by 58 Mandarin-speaking kindergarten-aged children in Taiwan. Children were randomly assigned to one of two experimental conditions or a control condition. Experimental groups participated in a learning session of four English words: band, nest, brick, and stool, with a perceptual or articulation focus on clusters, which do not exist in Mandarin. Outcome measures examined subjects’ ability to match words on the basis of shared onset or coda, and to elicit common units in both Mandarin and English before and after training. Significant gain in English onset common unit test scores was observed for the production training group, relative to the control group, especially in trials containing the trained clusters: br- and st-. Perception group however did not show an improvement over time across all measures. Between-group differences were not observed for English codas, Chinese onsets, or Chinese codas. Findings revealed that clearly articulating non-native words with unfamiliar syllable structures could assist children to isolate onsets in explicit phonological awareness tasks, independent of exposure to alphabetic orthography, generally thought to be critical in explicit phonological awareness (e.g., Gombert, 1992).
Second language word segmentation in a fluent speech listening task.
Authors: Adams Tuuli M.
Published: October 2013

Extracting words from a continuous speech stream is a complex task involving the integration of multiple linguistic cues. Like infants, adults have been shown to use both distributional information through statistical learning, and metrical and intonational information, when segmenting words in a second language. This study investigates adults’ native language influence on speech segmentation, and the extent to which linguistic knowledge is augmented by exposure to fluent, natural speech in a second language. In the experiment, English listeners completed a word learning task in an unfamiliar language, Finnish. Next, they listened to a fluent speech passage which contained learned words, as well as syllable sequences controlled for the same frequencies and transitional probabilities as the real words. English speakers have been shown to use acoustic stress cues to locate word boundaries, and while Finnish has a regular stress pattern, other phonotactic patterns could affect English listeners' segmentation abilities. Afterwards, they completed a forced-choice identification task, choosing from pairs of real and non-words, including incorrectly segmented syllable sequences, to identify the token which is more likely a word in Finnish. The behavioral data are analyzed for patterns reflecting the integration of native language linguistic knowledge and statistical learning abilities.
Head-related transfer function enhancement for improved vertical-polar localization.
Authors: Brungart Douglas S. , Romigh Griffin D. , Simpson Brian D.
Published: October 2013

Under ideal laboratory conditions, individualized head-related transfer functions (HRTFs) can produce virtual sound localization performance approaching the level achieved with real sound sources in the free field. However, in real-world applications of virtual audio, practical issues such as fit-refit variability in the headphone response and nonindividualized HRTFs generally lead to much worse localization performance, particularly in the up-down and front-back dimensions. Here we present a new technique that “enhances” the localizability of a virtual sound source by increasing the spectral contrast of the acoustic features that are relevant for spatial perception within a set of locations with nearly identical binaural cues (i.e., a “cone-of-confusion”). Validation experiments show that this enhancement technique can improve localization accuracy across a broad range of conditions, with as much as a 33% reduction in vertical-polar localization error for nonindividualized HRTFs measured on a KEMAR manikin; a 25% reduction in vertical-polar error for nonindividualized HRTFs measured on other human listeners; and a 33% reduction in vertical-polar error for individualized HRTFs presented under nonideal laboratory conditions (i.e., with headphone fit-refit variability). These results suggest that the proposed technique could provide benefits across a wide range of real-world virtual audio display applications. [Work sponsored by AFOSR.]
Bayesian geoacoustic inversion and source tracking for horizontal line array data
Authors: Tollefsen Dag
Published: October 2013

This thesis develops non-linear Bayesian methods for three-dimensional tracking of a moving acoustic source in shallow water despite environmental uncertainty, with application to data from a horizontal line array (HLA) of hydrophones. Focalization-tracking maximizes the posterior probability density (PPD) over track and environmental parameters. Synthetic test cases show that the algorithm substantially outperforms tracking with poor environmental estimates and generally obtains results close to those achieved with exact environmental knowledge. Marginalization-tracking integrates the PPD over environmental parameters to obtain joint marginal distributions over source coordinates, from which track uncertainty estimates and the most probable track are extracted. Both approaches are applied to HLA data from a shallow-water experiment conducted in the Barents Sea. Focalization-tracking successfully estimates the tracks of a towed source and a surface ship in cases where simpler tracking algorithms fail. Marginalization-tracking generally outperforms focalization-tracking and gives uncertainty estimates that encompass the true tracks. As a precursor, Bayesian geoacoustic inversion is applied (to both controlled-source and ship-noise data) to estimate seabed model parameters and their uncertainties. It is demonstrated that combining data from multiple, independent time-series segments in the inversion can significantly reduce geoacoustic parameter uncertainties. Geoacoustic uncertainties are also shown to depend on ship range and orientation.
An Aneurysm Model to Help Predict the Unpredictable.
Authors: Balcells Mercedes
Published: October 2013

A porcine model of thoracic aortic aneurysm closely recapitulates the clinical hallmarks of this disease.
SuhB Is a Regulator of Multiple Virulence Genes and Essential for Pathogenesis of Pseudomonas aeruginosa
Authors: Li Kewei , Xu Chang , Jin Yongxin , Sun Ziyu , Liu Chang , Shi Jing , Chen Gukui , Chen Ronghao , Jin Shouguang , Wu Weihui
Published: October 2013

During initial colonization and chronic infection, pathogenic bacteria encounter distinct host environments. Adjusting gene expression accordingly is essential for the pathogenesis.Pseudomonas aeruginosahas evolved complicated regulatory networks to regulate different sets of virulence factors to facilitate colonization and persistence. The type III secretion system (T3SS) and motility are associated with acute infections, while biofilm formation and the type VI secretion system (T6SS) are associated with chronic persistence. To identify novel regulatory genes required for pathogenesis, we screened aP. aeruginosatransposon (Tn) insertion library and foundsuhBto be an essential gene for the T3SS gene expression. The expression ofsuhBwas upregulated in a mouse acute lung infection model, and loss ofsuhBresulted in avirulence. Suppression of T3SS gene expression in thesuhBmutant is linked to a defective translation of the T3SS master regulator, ExsA. Further studies demonstrated thatsuhBmutation led to the upregulation of GacA and its downstream small RNAs, RsmY and RsmZ, triggering T6SS expression and biofilm formation while inhibiting the T3SS. Our results demonstrate that anin vivo-inducible gene,suhB, reciprocally regulates genes associated with acute and chronic infections and plays an essential role in the pathogenesis ofP. aeruginosa.

IMPORTANCEA variety of bacterial pathogens, such asPseudomonas aeruginosa, cause acute and chronic infections in humans. During infections, pathogens produce different sets of virulence genes for colonization, tissue damage, and dissemination and for countering host immune responses. Complex regulatory networks control the delicate tuning of gene expression in response to host environments to enable the survival and growth of invading pathogens. Here we identifiedsuhBas a critical gene for the regulation of virulence factors inP. aeruginosa. The expression ofsuhBwas upregulated during acute infection in an animal model, and mutation ofsuhBrenderedP. aeruginosaavirulent. Moreover, we demonstrate that SuhB is required for the activation of virulence factors associated with acute infections while suppressing virulence factors associated with chronic infections. Our report provides new insights into the multilayered regulatory network of virulence genes inP. aeruginosa.
Next-generation sequencing in childhood disorders
Authors: Schnekenberg Ricardo Parolin , Németh Andrea H
Published: October 2013

Genetics has been revolutionised by recent technologies. The latest addition to these advances is next-generation sequencing, which is set to transform clinical diagnostics in every branch of medicine. In the research arena this has already been instrumental in identifying hundreds of novel genetic syndromes, making a molecular diagnosis possible for the first time in numerous refractory cases. However, the pace of change has left many clinicians bewildered by new terminology and the implications of next-generation sequencing for their clinical practice. The rapid developments have also left many diagnostic laboratories struggling to implement these new technologies with limited resources. This review explains the basic concepts of next-generation sequencing, gives examples of its role in clinically applied research and examines the challenges of its introduction into clinical practice.