bluuebunny/crossref_metadata_2025 huggingface dataset:
Sensitivity to input distributions and decision boundaries in auditory category learning.
Authors: Lim Sung-joo , Holt Lori L.
Published: October 2009

Previous research demonstrates the sensitivity of adults and infants to the statistical regularity of input distributions defining speech categories [D. L. Grieser and P. K. Kuhl, Dev. Psychol. 25, 577–588 (1989)] and even non-human animals exhibit such sensitivity [Kluender et al., J. Acoust. Soc. Am. 104, 3568–3580 (1998)]. Speech categories’ structure also possesses information to support the use of decision boundaries in categorization. To investigate the interaction of distribution versus decision-boundary information in auditory category learning, the current research tracked listeners learning novel non-speech categories defined by two acoustic dimensions, the center frequency and modulation frequency, via explicit training with feedback. Early in learning, listeners exhibited sensitivity to distributional regularities of categories by robustly responding to more densely sampled regions of acoustic space. However, evidence of listeners’ reliance on a decision boundary emerged once learning plateaued. The point in learning at which decision boundaries predicted categorization response was determined not only by the type of listeners’ prior experience with the sounds but also by the perceptual salience of the acoustic dimensions. [Work supported by NSF.]
Investigation of the neural bases of context-dependent speech categorization.
Authors: Laing Erika J. C. , Holt Lori L. , Bagic Anto
Published: October 2009

Previous research has demonstrated that simple sequences of preceding sine-wave tones affect speech categorization in a spectrally-contrastive manner [L. Holt, Psychol. Sci. 16, 305–312 (2005)]. The current research explicitly links these effects to effects commonly thought to be instances of talker normalization [P. Ladefoged and D. E. Broadbent, J. Acoust. Soc. Am. 29, 98–103 (1957)]. Synthesized sentences manipulated to sound like different talkers influence categorization of a subsequent speech target only when sentences’ long-term average spectra (LTAS) predict spectral contrast. Likewise, sequences of tones modeling these LTAS differences produce parallel context-dependent speech categorization effects. The predictiveness of LTAS, rather than perceived talker, suggests that general auditory rather than speech-specific or articulatorily-driven mechanisms may play a role in effects considered to be instances of talker normalization. The behavioral measures are paired with magnetoencephalography (MEG) to investigate the neural bases of these parallel effects. Listeners categorized a /ga/-/da/ series in the context of preceding sentences and nonspeech tone sequences varying in their LTAS while MEG signals were acquired. Analyses focus on how the speech target is encoded as a function of preceding LTAS and the status of the context as speech or nonspeech. [Work supported by NIH and NOHR.]
Potential information predicts sentence intelligibility better than vowels, consonants, or duration.
Authors: Stilp Christian E. , Kluender Keith R.
Published: October 2009

Speech sounds are typically divided into consonants and vowels. When either vowels or consonants, as delineated in TIMIT sentences, are replaced by noise, listeners are more accurate understanding sentences in which consonants are replaced relative to sentences in which vowels are replaced. From such data, vowels have been suggested to be more important for understanding sentences; however, interpretation of these data is unclear because consonant segments are roughly one-third shorter than vowels as marked within TIMIT. We report two experiments that demonstrate listener performance is better predicted by simple acoustic measures of spectral change, not duration or consonant/vowel distinction. First, listeners identified sentences in which consonants, vowels, C-V transitions, or V-C transitions were replaced by speech-shaped noise. Contrary to previous work, performance suffered most when consonants were replaced by noise. In a second experiment, portions of sentences were replaced based on cochlea-scaled spectral entropy (change across time). Speech segments having relatively high, medium, or low change over 80-ms (consonant duration) or 112-ms (vowel duration) intervals were replaced with noise. Intelligibility decreased linearly as amount of replaced spectral entropy increased independent of duration. Spectral change (entropy) is more important than consonant/vowel distinctions and duration. [Work supported by NIDCD.]
The perceptual time course of coarticulatory nasalization.
Authors: Beddor Patrice S. , Boland Julie E. , Coetzee Andries , McGowan Kevin
Published: October 2009

Listeners’ moment-by-moment processing of anticipatory vowel nasalization and a following nasal consonant was investigated. English-speaking participants’ eye movements were monitored as they heard instructions to look at one of two pictured objects on a computer screen. Trials included pictured pairs for naturally produced words of the form CVNC-CVC (e.g., bend-bed), CVNC-CVNC (bend-bent), and CVC-CVC (bed-bet). Vowels in CVNC words were coarticulatorily nasalized. Results to date show that, when participants heard a CVNC word (bend), they visually fixated the correct picture earlier when the competing picture was CVC (bed)—that is, when the vowel in the competitor would be expected to be non-nasal—than when the competitor was another CVNC word (bent). Results also suggest that participants often fixated the target CVNC picture in CVNC-CVC trials after onset of vowel nasalization but before N onset. However, although vowel nasalization facilitated early selection of CVNC over CVC, a non-nasalized vowel was not similarly helpful for selecting CVC over CVNC. When participants heard CVC (bed), they did not fixate the correct picture earlier when the competing picture was CVNC (bend) than when the competitor was CVC (bet). Findings are interpreted in light of production data for English and perceptual theories.
Effects of native language on perception of the relative amplitudes of the first and second harmonics.
Authors: Kreiman Jody , Gerratt Bruce R. , ud Dowla Khan Sameer
Published: October 2009

As an incidental result of previous studies of the perception of spectral slope, we found that Mandarin speakers were nearly twice as sensitive to changes in the amplitude of the first harmonic relative to the second (H1-H2) as are English speakers. Although two Mandarin tones are typically produced with characteristic changes in voice quality, Mandarin does not contrast phonation types directly. Thus, the observed difference between listener groups could be due to increased attention to overall source characteristics in speakers of tone languages (because F0=H1), or specifically to experience with voice quality differences apart from F0. To clarify this matter, we measured just-noticeable differences in H1-H2 for speakers of Gujarati, a non-tonal language that contrasts breathy and modal vowels in H1-H2, and for speakers of a language like Yoruba that contrasts tones but not phonation types. If increased sensitivity to H1-H2 differences is due to attention to H1, then just-noticeable differences for both groups should be smaller than those for English speakers. However, if perceptual experience specifically with the H1-H2 contrast is required, then Gujarati speakers, but not Yoruba speakers, should show increased sensitivity relative to English speakers. [Research supported by NIH and NSF.]
Observed anisotropy in low frequency acoustic signal loss at the sea floor.
Authors: Wood Warren , Lindwall Dennis , Bangs Nathan
Published: October 2009

Anisotropy of 20%–30% in the low-frequency (10–120 Hz) acoustic bottom loss of marine sediments 1200-m deep off the coast of Oregon is reported here. Two nearly perpendicular acoustic profiles were acquired with air guns towed at the sea surface, crossing at a point directly over a four-component ocean bottom seismometer (OBS) on the seafloor. The area is a convergent margin, with a regional principal stress field perpendicular to broad bathymetric ridges and the shoreline, and numerous faults running parallel to the bathymetry. Amplitudes of sediment reflections are consistently 20%–30% less on the profile parallel to the bathymetry than on the profile perpendicular to the bathymetry. This is the opposite of what would be expected if the dominant attenuation mechanism were scattering from the fault planes. The anisotropy exists at angles for which acoustic energy penetrates sediments only a few hundred meters from the crossing point, where layering in both directions is laterally consistent. The direct arrival amplitudes, from the source to the OBS, are identical on both transects, suggesting that neither the acquisition technique nor the water column is responsible for the anisotropy. Possible explanations include seafloor bed forms and wavelength-scale roughness at the buried sediment interfaces.
Impact of shelfbreak fronts on long-range underwater sound propagation in the continental shelf area.
Authors: Lin Ying-Tsong , Shmelev Alexey , Lynch James F. , Newhall Arthur E. , Lermusiaux Pierre F. J.
Published: October 2009

The dynamic shelfbreak front commonly observed in the continental shelf area has significant impact on underwater sound propagation. Analytical study with an idealized front model has shown that combining inshore refraction from the front and offshore refraction on the sloping shelf, long-range propagating sound on the continental shelf will be trapped by the front and form “whispering gallery” modes on the inshore side of the front. In this paper, numerical propagation simulations with three-dimensional normal mode and parabolic approximation methods are implemented to investigate the acoustic impact of a nearly realistic front model. This front model results from the MIT Multidisciplinary Simulation, Estimation, and Assimilation System which assimilated the field measurements collected during the New Jersey Shelf Shallow Water 2006 experiment. Since the front model captures very well the temporal and spatial variability of the shelfbreak frontal system in the field, the numerical propagation simulations presented here are fairly realistic. Horizontal sound refraction due to the shelfbreak front and (sub)-mesoscale eddies are observed, and causes part of long-range propagating sound energy to be trapped on the shelf area.
Computational grid design to improve three-dimensional parabolic equation modeling efficiency.
Authors: Austin Melanie E. , Chapman N. Ross
Published: October 2009

One class of very accurate computer models that can be used to predict underwater acoustic fields is based on three-dimensional (3-D) solutions of the parabolic form of the reduced acoustic wave equation. 3-D parabolic equation (PE) models contain differential operators in both depth and azimuth. These 3-D solutions are very computationally intensive, but strategic definition of the model grid can save computation time. A 3-D PE model (MONM3D) has been developed that incorporates techniques that reduce the required number of model grid points. The concept of tessellation is used to optimize the radial grid density as a function of range, reducing the required number of grid points in the horizontal planes of the grid. The model marches the solution out in range along several radial propagation paths emanating from a source position. Tessellation, as implemented in MONM3D, allows the number of radial paths in the model grid to depend on range from the source. In addition, the model incorporates a higher-order azimuthal operator which allows a greater radial separation and reduces the required number of radial propagation paths. The efficiency and accuracy of the MONM3D model will be presented by demonstration of a test case.
Low-frequency sound field focusing in shallow water.
Authors: Petnikov Valeriy G. , Lunkov Andrey A. , Stromkov Alexander A.
Published: October 2009

Within the framework of numerical simulation a feasibility of low-frequency (100–300 Hz) sound field focusing was studied in the waveguide common to shallow water. Two types of focusing are discussed: focusing of a wide-band sound signal by time reversal mirror (TRM) and focusing of a monochromatic sound field by a phase conjugation mirror (PCM). It is demonstrated that if we use TRM we can focus sound field by both point source-receiver (SR) element and a corresponding SR vertical array. At the same time, the focusing quality is somewhat improved with vertical array, and TRM provides focusing with approximately the same quality as PCM operating at the frequency equal to the carrier frequency of a wide-band signal. It is shown that in a waveguide with a constant sound velocity at the range of 10 km wind waves deteriorate focusing quality at a wind speed greater than 12 m/s. [This research was supported by the Russian Foundation for Basic Research Project Nos. 08-02-00283 and 07-02-001205 and by the Civilian Research and Development Foundation Project No. REC 010.]
Visitor dose-response data acquisition protocol development at four U.S. National Parks.
Authors: Horonjeff Richard D. , Anderson Grant S.
Published: October 2009

In response to a mandate set forth by The National Parks Overflight Act of 1987 (PL 100-91), visitor response to tour aircraft overflights was sought by the National Park Service and the Federal Aviation Administration during the early 1990s. At issue was the extent to which varying doses of aircraft overflight noise resulted in both visitor-reported consequential degrees of annoyance and interference with an appreciation of natural quiet. This paper first presents a brief overview of the results of these studies (previously published in the literature), then focuses on the data collection protocol used. Several alternative dose and response data collection methodologies were considered and evaluated. This paper presents the perceived strengths and weakness of the various alternatives as well as the rationale behind the final adopted protocol. Deciding factors included cost, accepted social survey practices, ability to match noise doses with individual visitors, avoiding any pre-sensitization of visitors, and the ability to separate potentially confounding variables during data analysis. [Work supported by the National Park Service and the Federal Aviation Administration.]
Soundscape documentation of parks and natural areas.
Authors: Siebein Gary W. , Skelton Reece
Published: October 2009

A multi-media method to document the distinctions among qualities of sounds with relatively similar levels in a natural, outdoor environment was developed. Simultaneous recordings of sound levels, calibrated aural recordings of .wav files of specific acoustic events, and video photography of the events were overlaid on a map of the site to document the itinerary of the observer. The multi-media method attempted to more completely document the nature of the soundscape with its subtle changes in sources of sound, level, frequency, and time duration than typical environmental noise metrics such as Leq’s, LDN’s and other long term average sound metrics. The sound levels measured near the road are similar to those taken at locations within the park; however, the quality of sounds is very different from each other. The acoustical transition from a street edge into a dense, natural park was examined. The experiment shows how the nature of sound shifts dramatically through the site while the perceived average sound level remains relatively constant. The acoustical evaluation of the site includes both quantitative and qualitative elements so the true essence of a place can be considered and the subtle but important sonic qualities of sites can be designed.
Soundscapes and city noise ordinances.
Authors: Timmerman Nancy S.
Published: October 2009

The word “soundscape” has been used to get away from the negative connotations of the word “noise.” In reality, whether or not a sound or soundscape is annoying depends on the viewpoint of the listener. Two cities in Massachusetts, Boston and Somerville, will be examined to compare and contrast what soundscapes have been deemed “acceptable.” In addition, the Massachusetts state code, covering areas which do not have such ordinances, will also be examined.
Seattle’s Sound Transit Residential Sound Insulation Program reduces sound sustainably.
Authors: Wiebusch Julie A.
Published: October 2009

Light Rail has arrived in Seattle, making access to downtown easier and more efficient through the new 14-mile light rail system. However, the new system brings with it an increase in noise levels for some residents. In order to minimize the annoyance for those residents along the alignment, Sound Transit has created a Residential Sound Insulation Program (RSIP). The initial program provided 137 residences with a package to reduce the intrusion of exterior sound and to increase the ventilation and air quality within the home. Sound Transit has taken the process one step further with its commitment that RSIP will have zero impact on local landfills.
Characterizing Rayleigh damping parameters of post-cured, hybrid, methacrylic materials used in stereolithography systems.
Authors: Burns Thomas H. , Beeson Andrew R.
Published: October 2009

Stereolithographic systems of methacrylic are commonly used in the large-scale production of custom earmolds for hearing aids. In hearing aids, feedback occurs when energy from the receiver (earphone) is sensed by the microphone; the feedback manifests itself as an annoying whistle. One source of feedback is the mechanical vibration transmitted by the receiver to the microphone through the structural housing or earmold. Mechanical feedback can be reduced by appropriately designing the earmold housing to have proper isolation features and damping so as to minimize mechanical transmissibility. Toward this end, a procedure is described that utilizes both experimental measurements and finite element analyses to characterize an earmold material’s stiffness and damping in the frequency range of 500 Hz–6 kHz. The experimental set-up consists of an electromagnetic shaker, laser vibrometer, dual-channel analyzer, and multiple cantilever (fixed-free) sample beams fabricated from post-cured, hybrid, methacrylic polymers. The dimensions of the samples are chosen so that the resonance frequencies are sufficiently distributed over the aforementioned frequency range. Bending resonances are measured and compared to a finite element model via a half-power bandwidth technique; parameters for Young’s modulus, the loss factor, and Rayleigh damping are amended in the numerical model to match the empirical results.
Consequences of short-term language exposure in infancy on babbling.
Authors: Ward Nancy , Sundara Megha , Conboy Barbara , Kuhl Patricia
Published: October 2009

Kuhl et al. [Proc. Natl. Acad. Sci. U.S.A. 100, 9096–9101 (2003)] showed that the decline in the discrimination of non-native perceptual contrasts observed during development can be reversed with short-term exposure to a non-native language. In this poster, the question of whether short-term exposure also impacts the speech produced by infants is addressed. For this purpose, 9–10-month-old infants from monolingual English-speaking households were exposed to Spanish for a total of 5 h over 6 weeks (12 25-min sessions). At the end of this exposure, babbling data were collected from the infants in two sessions with (a) an English-speaking parent and (b) a Spanish-speaking research assistant. In this experiment, adult listeners were tested in their ability to identify the babbling produced by these infants as English or Spanish. Canonical syllables and multi-syllabic utterances from these sessions were played to adult native speakers of English and Spanish, who identified the tokens as English or Spanish using a forced-choice paradigm. Results will be discussed in the context of the literature on short-term exposure as well as the effects of social interactions on language acquisition.
Acoustic analysis of the English pronunciation of Japanese high school teachers and university students.
Authors: Wilson Ian L. , Fujinuma Junichi , Horiguchi Naoya , Yamauchi Kazuaki
Published: October 2009

As Japan attempts to meet the demands of the Ministry of Education by introducing English-as-a-foreign-language (EFL) classes in all elementary schools, there has been a shortage of qualified native Japanese EFL teachers. The English communicative ability (and pronunciation, in particular) of Japanese EFL teachers varies across educational levels throughout Japan and even within individual prefectures. This study presents an acoustic analysis of 77 Fukushima Prefecture junior and senior high school Japanese EFL teachers’ read speech, comparing the two levels. It also presents an analysis of 133 Japanese university students’ read speech, recorded both before and after 14 weeks of weekly 90-min explicit pronunciation instruction. The reading passage was the “Please call Stella” paragraph from the speech accent archive (http://accent.gmu.edu/). Detailed analyses of vowel formants, voice onset time, fricative spectral peaks, and intonation were carried out using PRAAT and will be presented. The data have implications for curriculum planning for both EFL pronunciation classes and teacher training courses in Japan.
Perception of English vowels by Chinese learners in Taiwan.
Authors: Yang Li-chin , Lai Yu-da
Published: October 2009

The aim of this study attempts to explore how the structure of the native language and the markedness affect the perception of English vowels by Chinese learners in Taiwan. This paper concerns how people of different English proficiency levels perceive English vowels in terms of the similarity degrees of the vowels in both native and target languages (3 groups × 3 vowel similarity degrees). Thirty Mandarin and Southern Min speaking subjects, equally distributed in three English proficiency levels, namely, low, mid, and high, participated in the study. The quantitative analysis regarded the similarity degrees of the vowels in both native and target languages as three: identical, similar with counterpart, and new. This study also investigated how similar or new vowels are perceived by learners of different English proficiency levels (3 groups × 3 vowel markedness degrees). The similar or new vowels, according to P. Smolensky (1993) and Lombardi (1997), were divided into three categories of markedness: the most marked (rounded and back vowels), marked (front vowels), and unmarked (low vowels). Results showed the influence of both the markedness of English vowels and the different structures between English and native languages. Finally, they were explained via optimality theory.
Cross language effects on vowel perception in noise: Detection of English vowels spoken by English, Chinese, and Korean talkers.
Authors: Jin Su-Hyun , Liu Chang , Kamdar Sangeeta
Published: October 2009

The purpose of this study was to measure detection thresholds for 12 isolated American English vowels spoken by English (E), Chinese (C), and Korean (K) talkers for young normal-hearing listeners in the presence of a long-term speech-shaped noise presented at 70-dB SPL. Two groups of talkers were selected from each Chinese and Korean talkers based on the vowel intelligibility found from the previous study [Jin et al., (2009)]: high and low intelligibility groups. Each group consisted of male and female talkers. Two English talkers (a male and female) were also included as a control. Preliminary analysis indicated that there was no statistically significant difference in the detection thresholds for vowels produced by native and non-native talkers. However, thresholds for vowels differed by 20 dB across the 120 vowels (12 vowels × 10 talkers), which is consistent with Liu and Eddins (2008). It suggested that regardless of the language background of talkers, vowel detectability might be more influenced by vowel category and individual talker. The effect of acoustic features (both temporal and spectral cues) in each vowel on native English listeners’ detection thresholds will be discussed.
The effects of linguistic experience on the perception of [h].
Authors: Garellek Marc
Published: October 2009

Languages with onset-[h] are thought to be more likely to develop coda-[h] than languages with no [h] at all [D. Silverman, Phasing and Recoverability (Garland, New York, 1997)]. It is therefore expected that speakers of languages with onset-[h] should be more likely to perceive coda-[h] than speakers of a language with no [h]. The goal of this study is to test this hypothesis. Speakers of French (a language with no [h]) and English (which allows onset-[h]) were instructed to monitor for [h] in strings of nonce words with [h] in onset or coda positions. If English speakers perform significantly better than French speakers on coda-[h] perception, then the hypothesis is supported. Subjects also participated in a mispronunciation detection task, where they monitored for errors in words of their language. The stimuli were common English and French monosyllabic words ending in [s, f, ∫], with the fricatives spliced and replaced with [h], keeping the formant transitions intact. The stimuli were randomly placed in a string of native words with no contextual cues. If the hypothesis is supported, findings should show faster and more accurate mispronunciation detection for English speakers than French speakers, suggesting that English speakers are more likely to perceive coda-[h].
A mode solution for sediment-refracted wave propagation.
Authors: Clark Cathy Ann
Published: October 2009

An normal mode solution for low-frequency bottom-sediment refracted wave propagation is formulated for use with a normal mode method of solving the Helmholtz wave equation to describe the underwater sound field for a fixed point source in a plane multilayered medium. The approach utilizes a factorization of the Wronskian of the Green’s function which enables sediment reflecting and refracting modes to be summed independently. The sensitivity of propagation loss to the nature of mode interaction with the bottom is investigated for a sample environment and results are compared to measured data.
Estimating geoacoustic properties of marine sediment on the New Jersey Continental Shelf from broadband signals.
Authors: Jiang Yong-Min , Chapman N. Ross
Published: October 2009

This paper presents geoacoustic inversions of broadband signals collected in the Shallow Water 2006 Experiments off the coast of New Jersey. An L-shaped array was deployed on the top of a sand ridge, in 70 m of water. The acoustic source was maintained at a distance of 190 m from the vertical leg of the L-shape array, and lowered from 10 to 60 m in 10-m intervals in the experiment. Two sets of chirps, low frequency (100–900 Hz) and midfrequency (1100–2900 Hz), were transmitted with approximately the same experimental geometry. The water column sound speed profiles were measured at the source position. This study examines the sediment information content from different frequency bands recorded on the vertical leg of the L-shape array. Because the chirps have different temporal resolutions and energy penetrabilities in the sediment, the received signals exhibit different bottom structures at different frequency bands. Travel time geoacoustic inversions are carried out at both frequency bands using signals from the resolvable reflections from the sediment layers. The variation in the oceanic sound speed profile is parametrized in terms of its characteristics and included in the inversion. [Work supported by ONR Ocean Acoustics.]
Endovascular treatment of carotid blowout syndrome: who and how to treat
Authors: Patsalides A , Fraser J F , Smith M J , Kraus D , Gobin Y P , Riina H A
Published: October 2009

Carotid blowout syndrome (CBS) is a high-risk condition associated with significant morbidity and mortality that may result from invasion and destruction of the cervical carotid vasculature from head and neck squamous cell carcinoma. Endovascular approaches offer multiple modalities for treatment to prevent morbidity and death. In this paper we review our experience in addressing CBS and present an up-to-date algorithm of endovascular management.

16 lesions were identified in 8 patients treated with 9 procedures over the past year. Pseudoaneurysm and/or active extravasation were documented in at least one vessel in all 8 cases presenting with acute CBS. There were 13 pseudoaneurysms in external carotid artery (ECA) trunk (5), ECA branches (4), internal carotid artery (ICA) (1) and common carotid artery (CCA) (3). There were 3 additional ICA lesions due to tumor infiltration, resulting in ICA occlusion (2) and long segment stenosis (1).

Permanent vessel occlusion was performed in 11 lesions of the ECA trunk (4), ECA branches (4) and ICA (3). Stent-grafts were placed in 5 lesions in the CCA (3), ICA (1) and ECA trunk (1). Technical success and immediate hemostasis were achieved in all patients. There were no procedural deaths or immediate complications. With a median follow-up of 2 months (range, 1–13 months), three patients died: one from recurrent CBS, one from global brain ischemia after a cardiac arrest event unrelated to CBS and one from systemic disease. There was no other recurrence of bleeding or neurological complication.

Endovascular techniques offer an armamentarium to effectively address CBS, significantly affecting the care and outcome in this particular oncologic population. These techniques should be offered as early as possible in the context of a multidisciplinary approach.
Buckling deformation in the Highwood Pass, Alberta, Canada
Authors: Hu Xian-Qin , Cruden D. M.
Published: October 2009

Buckling of beds in the sedimentary rocks in the Highwood Pass, Alberta, Canada, occurs on steep underdip and dip slopes. The modes of buckling are determined by bedding thickness. We distinguish Euler buckles that develop in beds without cross fractures, block-flexure buckles that form with smooth buckled bedding surfaces in beds with cross fractures, and block buckles that develop with large rotations of rock blocks in rock layers more than 0.1 m thick. Chevron buckles resembling chevron folds develop in beds less than 0.1 m thick. Buckles can be displaced further to form roof and wall structures or cascades. Key words : buckling, critical load, slope stability, natural rock slope.
Behavior of clayey soils on drying–wetting paths
Authors: Fleureau Jean-Marie , Kheirbek-Saoud Siba , Soemitro Ria , Taibi Said
Published: October 2009

Experimental research was carried out on 11 different clayey materials to determine the main characteristics of the drying and wetting paths and the influence of initial state and other factors. Normally consolidated paths are shown to have a large saturated domain, in which a negative pressure is equivalent to an isotropic stress increase; such paths can be derived from correlations with the liquid limit. On the other hand, the behavior of overconsolidated or dried samples is largely dependent on the range of stresses and negative pressures. Key words : suction, unsaturated soils, drying, wetting, correlations, models.
Field and laboratory experience with the use of strip drains in organic soils
Authors: Koda E. , Szymanski A. , Wolski W.
Published: October 2009

The results of field and laboratory investigations performed on two test sites located on organic soils in northwestern Poland are presented. Comprehensive investigations comprising observations at four test embankments and a laboratory investigation were carried out to study the influence of vertical drains on the consolidation process in organic subsoil and the behaviour of Geodrains-type strip drains in organic soils. It was shown that vertical strip drains may effectively improve the bearing capacity of amorphous peat and gyttja for stage-constructed embankments. However, it has been observed that there is a significant decrease in discharge capacity of Geodrains during embankment construction, depending on the type of drain filters (paper or polyester). Nevertheless, the vertical drain effectiveness was found to be quite satisfactory because the observed decrease of discharge capacity has practically no influence on consolidation rate. It was also detected that the buckling effect, probably owing to large horizontal displacements, does not significantly affect the discharge capacity of drains. Moreover, it is shown that there is a significant difference in pore-pressure distribution under embankments with and without vertical drains. As a result of the vertical drain installation under part of the slopes, a significant decrease in the horizontal displacements took place. Key words : consolidation, soil improvement, organic soils, vertical drains, field and laboratory tests.
Measurement of rock elastic moduli in tension and in compression and its practical significance
Authors: Stimpson B. , Chen Rui
Published: October 2009

The moduli of deformation of rock in tension and in compression are generally assumed equal. However, many rocks show different deformation properties when loaded in tension and in compression. This property is usually referred to as bimodularity. In this paper, a new testing technique in which moduli in both tension and compression can be measured on the same specimen in the same compressive loading frame is described. Testing results from halite, potash, granite, and limestone indicate that moduli in compression and in tension are different for at least three of these materials. The new testing technique is validated against the standard uniaxial tension and uniaxial compression tests on potash and halite. Also, results from granite by the new testing technique are comparable with previously published data. The practical significance of rock bimodularity is discussed as well. It is demonstrated that this property significantly influences the deflection and stress distribution in a simple beam problem. Bimodularity also influences the interpretation of indirect rock tension test results and the prediction of roof deflection in underground openings. Ignoring bimodularity overestimates rock tensile strength in most of the indirect rock tension tests and underestimates roof deflection. Key words : rock, elastic modulus, bimodularity, testing technique.
QUANTUM PROBABILITIES FROM DETECTION THEORY FOR CLASSICAL RANDOM FIELD
Authors: KHRENNIKOV ANDREI
Published: October 2009

We present a model of detectors operating with classical random fields and producing probabilities described by the formalism of quantum mechanics. The basic assumption of this measurement theory is that the probability of detection of field (= signal) is proportional to the power of this field. (Therefore we call this approach "power signal-field detection theory" – PFSDT.) Our approach has some similarities with stochastic electrodynamics. However, formalisms describing random fields – "quantum fluctuations" – are different. Moreover, our approach all particles are represented by random fields, e.g., electronic or neutronic field. Thus we have various types of "quantum fluctuations".
Chronically elevated plasma C-type natriuretic peptide level stimulates skeletal growth in transgenic mice
Authors: Kake Takei , Kitamura Hidetomo , Adachi Yuichiro , Yoshioka Tetsuro , Watanabe Tomoyuki , Matsushita Hiroaki , Fujii Toshihito , Kondo Eri , Tachibe Takanori , Kawase Yosuke , Jishage Kou-ichi , Yasoda Akihiro , Mukoyama Masashi , Nakao Kazuwa
Published: October 2009

C-type natriuretic peptide (CNP) plays a critical role in endochondral ossification through guanylyl cyclase-B (GC-B), a natriuretic peptide receptor subtype. Cartilage-specific overexpression of CNP enhances skeletal growth and rescues the dwarfism in a transgenic achondroplasia model with constitutive active mutation of fibroblast growth factor receptor-3. For future clinical application, the efficacy of CNP administration on skeletal growth must be evaluated. Due to the high clearance of CNP, maintaining a high concentration is technically difficult. However, to model high blood CNP concentration, we established a liver-targeted CNP-overexpressing transgenic mouse (SAP-CNP tgm). SAP-CNP tgm exhibited skeletal overgrowth in proportion to the blood CNP concentration and revealed phenotypes of systemic stimulation of cartilage bones, including limbs, paws, costal bones, spine, and skull. Furthermore, in SAP-CNP tgm, the size of the foramen magnum, the insufficient formation of which results in cervico-medullary compression in achondroplasia, also showed significant increase. CNP primarily activates GC-B, but under high concentrations it cross-reacts with guanylyl cyclase-A (GC-A), a natriuretic peptide receptor subtype of atrial natriuretic peptides (ANP) and brain natriuretic peptides (BNP). Although activation of GC-A could alter cardiovascular homeostasis, leading to hypotension and heart weight reduction, the skeletal overgrowth phenotype in the line of SAP-CNP tgm with mild overexpression of CNP did not accompany decrease of systolic blood pressure or heart weight. These results suggest that CNP administration stimulates skeletal growth without adverse cardiovascular effect, and thus CNP could be a promising remedy targeting achondroplasia.
Activation of sodium-glucose cotransporter 1 ameliorates hyperglycemia by mediating incretin secretion in mice
Authors: Moriya Ryuichi , Shirakura Takashi , Ito Junko , Mashiko Satoshi , Seo Toru
Published: October 2009

Glucose ingestion stimulates the secretion of the incretin hormones, glucose-dependent insulinotropic peptide (GIP) and glucagon-like peptide-1 (GLP-1). Despite the critical role of incretins in glucose homeostasis, the mechanism of glucose-induced incretin secretion has not been established. We investigated the underlying mechanism of glucose-induced incretin secretion in vivo in mice. Injection of glucose at 1 g/kg in the upper intestine significantly increased plasma GIP and GLP-1 levels, whereas injection of glucose in the colon did not increase GIP or GLP-1 levels. This finding indicates that the glucose sensor for glucose-induced incretin secretion is in the upper intestine. Coadministration of a sodium-glucose cotransporter-1 (SGLT1) inhibitor, phloridzin, with glucose in the upper intestine blocked glucose absorption and glucose-induced incretin secretion. α-methyl-d-glucopyranoside (MDG), an SGLT1 substrate that is a nonmetabolizable sugar, significantly increased plasma GIP and GLP-1 levels, whereas phloridzin blocked these increases, indicating that concomitant transport of sodium ions and glucose (substrate) via SGLT1 itself triggers incretin secretion without the need for subsequent glucose metabolism. Interestingly, oral administration of MDG significantly increased plasma GIP, GLP-1, and insulin levels and reduced blood glucose levels during an intraperitoneal glucose tolerance test. Furthermore, chronic MDG treatment in drinking water (3%) for 13 days reduced blood glucose levels after a 2-h fast and in an oral glucose tolerance test in diabetic db/db mice. Our findings indicate that SGLT1 serves as the intestinal glucose sensor for glucose-induced incretin secretion and that a noncalorigenic SGLT1 substrate ameliorates hyperglycemia by stimulating incretin secretion.
Subsecond Timing in Primates: Comparison of Interval Production Between Human Subjects and Rhesus Monkeys
Authors: Zarco Wilbert , Merchant Hugo , Prado Luis , Mendez Juan Carlos
Published: October 2009

This study describes the psychometric similarities and differences in motor timing performance between 20 human subjects and three rhesus monkeys during two timing production tasks. These tasks involved tapping on a push-button to produce the same set of intervals (range of 450 to 1,000 ms), but they differed in the number of intervals produced (single vs. multiple) and the modality of the stimuli (auditory vs. visual) used to define the time intervals. The data showed that for both primate species, variability increased as a function of the length of the produced target interval across tasks, a result in accordance with the scalar property. Interestingly, the temporal performance of rhesus monkeys was equivalent to that of human subjects during both the production of single intervals and the tapping synchronization to a metronome. Overall, however, human subjects were more accurate than monkeys and showed less timing variability. This was especially true during the self-pacing phase of the multiple interval production task, a behavior that may be related to complex temporal cognition, such as speech and music execution. In addition, the well-known human bias toward auditory as opposed to visual cues for the accurate execution of time intervals was not evident in rhesus monkeys. These findings validate the rhesus monkey as an appropriate model for the study of the neural basis of time production, but also suggest that the exquisite temporal abilities of humans, which peak in speech and music performance, are not all shared with macaques.
Neuronal Encoding of Reward Value and Direction of Actions in the Primate Putamen
Authors: Hori Yukiko , Minamimoto Takafumi , Kimura Minoru
Published: October 2009

Decision making and action selection are influenced by the values of benefit, reward, cost, and punishment. Mapping of the positive and negative values of external events and actions occurs mainly via the discharge rates of neurons in the cerebral cortex, the amygdala, and the basal ganglia. However, it remains unclear how the reward values of external events and actions encoded in the basal ganglia are integrated into reward value-based control of limb-movement actions through the corticobasal ganglia loops. To address this issue, we investigated the activities of presumed projection neurons in the putamen of macaque monkeys performing a visually instructed GO–NOGO button-press task for large and small rewards. Regression analyses of neuronal discharge rates, actions, and reward values revealed three major categories of neurons. First, neurons activated during the preinstruction delay period were selective to either the GO(large reward)–NOGO(small reward) or NOGO(large reward)–GO(small reward) combinations, although the actions to be instructed were not predictable. Second, during the postinstruction epoch, GO and NOGO action-related activities were highly selective to reward size. The pre- and postinstruction activities of a large subset of neurons were also selective to cue position or GO-response direction. Third, neurons activated during both the pre- and postinstruction epochs were selective to both action and reward size. The results support the view that putamen neurons encode reward value and direction of actions, which may be a basis for mediating the processes leading from reward-value mapping to guiding ongoing actions toward their expected outcomes and directions.
fMRI-Guided TMS on Cortical Eye Fields: The Frontal But Not Intraparietal Eye Fields Regulate the Coupling Between Visuospatial Attention and Eye Movements
Authors: Van Ettinger-Veenstra H. M. , Huijbers W. , Gutteling T. P. , Vink M. , Kenemans J. L. , Neggers S. F. W.
Published: October 2009

It is well known that parts of a visual scene are prioritized for visual processing, depending on the current situation. How the CNS moves this focus of attention across the visual image is largely unknown, although there is substantial evidence that preparation of an action is a key factor. Our results support the view that direct corticocortical feedback connections from frontal oculomotor areas to the visual cortex are responsible for the coupling between eye movements and shifts of visuospatial attention. Functional magnetic resonance imaging (fMRI)–guided transcranial magnetic stimulation (TMS) was applied to the frontal eye fields (FEFs) and intraparietal sulcus (IPS). A single pulse was delivered 60, 30, or 0 ms before a discrimination target was presented at, or next to, the target of a saccade in preparation. Results showed that the known enhancement of discrimination performance specific to locations to which eye movements are being prepared was enhanced by early TMS on the FEF contralateral to eye movement direction, whereas TMS on the IPS resulted in a general performance increase. The current findings indicate that the FEF affects selective visual processing within the visual cortex itself through direct feedback projections.
Computer-Mouse Tracking Reveals TMS Disruptions of Prefrontal Function During Semantic Retrieval
Authors: Hindy Nicholas C. , Hamilton Roy , Houghtling Andrea S. , Coslett H. Branch , Thompson-Schill Sharon L.
Published: October 2009

Converging evidence from neuroimaging and neuropsychological studies is essential for understanding human frontal cortical function. We introduce a new method for studying the effects of transient disruptions of frontal activity during transcranial magnetic stimulation (TMS). Using a novel combination of TMS and computer-mouse tracking, through two experiments we tested process models of semantic competition in left ventrolateral prefrontal cortex (VLPFC). On TMS stimulation of left mid-VLPFC just after presentation of an ambiguous stimulus, participants' mouse-movement trajectories deviated more toward the incorrect target for weak associate trials than for any other trial type. This effect was extinguished when participants were simultaneously shown both target and cue stimuli. Results suggest that left mid-VLPFC is necessary to resolve semantic competition when a response is underdetermined by the stimulus and the interpretive context of the stimulus is ambiguous. Computer-mouse movements reveal the dynamics of competitive interactions as they resolve, making this technique ideally suited for studying cognitive control processes and a more sensitive index of TMS disruption than reaction time and accuracy alone.
Noise-Gated Encoding of Slow Inputs by Auditory Brain Stem Neurons With a Low-Threshold K+ Current
Authors: Gai Yan , Doiron Brent , Kotak Vibhakar , Rinzel John
Published: October 2009

Phasic neurons, which do not fire repetitively to steady depolarization, are found at various stages of the auditory system. Phasic neurons are commonly described as band-pass filters because they do not respond to low-frequency inputs even when the amplitude is large. However, we show that phasic neurons can encode low-frequency inputs when noise is present. With a low-threshold potassium current ( IKLT), a phasic neuron model responds to rising and falling phases of a subthreshold low-frequency signal with white noise. When the white noise was low-pass filtered, the phasic model also responded to the signal's trough but still not to the peak. In contrast, a tonic neuron model fired mostly to the signal's peak. To test the model predictions, whole cell slice recordings were obtained in the medial (MSO) and lateral (LSO) superior olivary neurons in gerbil from postnatal day 10 (P10) to 22. The phasic MSO neurons with strong IKLT, mostly from gerbils aged P17 or older, showed firing patterns consistent with the preceding predictions. Moreover, injecting a virtual IKLT into weak-phasic MSO and tonic LSO neurons with putative weak or no IKLT (from gerbils younger than P17) shifted the neural response from the signal's peak to the rising phase. These findings advance our knowledge about how noise gates the signal pathway and how phasic neurons encode slow envelopes of sounds with high-frequency carriers.