bluuebunny/crossref_metadata_2025 huggingface dataset:
Molecular Identification of Yeasts Associated with Traditional Egyptian Dairy Products
Authors: El‐Sharoud W.M. , Belloch C. , Peris D. , Querol A.
Published: July 2009

ABSTRACT:  This study aimed to examine the diversity and ecology of yeasts associated with traditional Egyptian dairy products employing molecular techniques in yeast identification. A total of 120 samples of fresh and stored Domiati cheese, kariesh cheese, and “Matared” cream were collected from local markets and examined. Forty yeast isolates were cultured from these samples and identified using the restriction‐fragment length polymorphism (RFLPs) of 5.8S‐ITS rDNA region and sequencing of the domains D1 and D2 of the 26S rRNA gene. Yeasts were identified as Issatchenkia orientalis (13 isolates), Candida albicans (4 isolates), Clavispora lusitaniae (Candida lusitaniae) (9 isolates), Kodamaea ohmeri (Pichia ohmeri) (1 isolate), Kluyveromyces marxianus (6 isolates), and Candida catenulata (7 isolates). With the exception of C. lusitaniae, the D1/D2 26S rRNA gene sequences were 100% identical for the yeast isolates within the same species. Phylogenetic reconstruction of C. lusitaniae isolates grouped them into 3 distinguished clusters. Kariesh cheese was found to be the most diverse in its yeast floras and contained the highest total yeast count compared with other examined dairy products. This was linked to the acidic pH and lower salt content of this cheese, which favor the growth and survival of yeasts in foodstuffs. Stored Domiati cheese also contained diverse yeast species involving isolates of the pathogenic yeast C. albicans. This raises the possibility of dairy products being vehicles of transmission of pathogenic yeasts.
The Importance of the Nativist–Empiricist Debate: Thinking About Primitives Without Primitive Thinking
Authors: Landau Barbara
Published: July 2009

Abstract— J. P. Spencer et al. (2009) are intent on dismantling the nativist–empiricist debate and they offer three main supporting arguments. It is argued here that these arguments are simply orthogonal to the authors’ main goal. More importantly, it is argued that even the most radical empiricist must embrace some set of primitives as the basis for learning; in some cases, rich primitives may actually be the learning mechanism. The nativist–empiricist debate is crucial to a healthy dialogue that allows us to think about how learning and development occur, and is therefore vital to our scientific progress.
Misrepresentational Innateness
Authors: Marcus Gary
Published: July 2009

Abstract— Both nature and nurture are important contributors to development, but the two are not mutually exclusive. Understanding their joint contribution will require a balanced look at both contributors. This commentary proposes that the target article by J. P. Spencer et al. (2009) falls short in this regard, largely because it misrepresents the very “nativist” position it seeks to critique.
Seeing the World Through a Third Eye: Developmental Systems Theory Looks Beyond the Nativist–Empiricist Debate
Authors: Spencer John P. , Samuelson Larissa K. , Blumberg Mark S. , McMurray Bob , Robinson Scott R. , Bruce Tomblin J.
Published: July 2009

Abstract—In response to the commentaries on our article (J. P.Spencer et al., 2009), we summarize what a developmental systems perspective offers for a 21st‐century science of development by highlighting 5 insights from developmental systems theory. Where applicable, the discussion is grounded in a particular example—the emergence of ocular dominance columns in early development. Ocular dominance columns are a paragon of epigenesis and are inconsistent with the nativist view. We conclude with optimism that developmental science can move beyond the nativist–empiricist debate armed with both modern technological tools and strong theory to guide their use.
How Gesture Promotes Learning Throughout Childhood
Authors: Goldin‐Meadow Susan
Published: July 2009

Abstract— The gestures children use when they talk often reveal knowledge that they do not express in speech. Gesture is particularly likely to reveal these unspoken thoughts when children are on the verge of learning a new task. It thus reflects knowledge in child learners. But gesture can also play a role in changing the child’s knowledge, indirectly through its effects on the child’s communicative environment and directly through its effects on the child’s cognitive state. Because gesture reflects thought and is an early marker of change, it may be possible to use it diagnostically. Gesture (or its lack) may be the first sign of future developmental difficulty. And because gesture can change thought, it may prove to be useful in the home, the classroom, and the clinic as a way to alter the pace, and perhaps the course, of learning and development.
Exploring Mathematics Difficulties in Children With Fetal Alcohol Spectrum Disorders
Authors: Rasmussen Carmen , Bisanz Jeffrey
Published: July 2009

Abstract— Fetal alcohol spectrum disorders (FASD) may cause a range of physical, mental, behavioral, and learning problems in children whose mothers consumed alcohol during pregnancy. One area of particular weakness for these children is mathematics, with deficits apparent even in studies that control for many potentially confounding variables and IQ. Deficits related to FASD are evident on many different components of mathematics, from standardized achievement measures to specific mathematics tests, and occur among young children, adolescents, and even adults. Children with FASD tend to have more difficulty with mathematics than with other cognitive areas, and mathematics is most highly correlated with the amount of prenatal alcohol exposure. To determine why math is such a significant area of weakness for children with FASD, research must explore how these children perform on different components of mathematics, the brain areas implicated in their mathematics deficits, the cognitive factors that underlie these deficits, and the profile of strengths and weaknesses of these children. Research also is needed on mathematical skills of preschool children with FASD and how math abilities develop in later years. Finally, studies are imperative on the efficacy of interventions designed to improve the math skills of children with FASD.
Establishment of a reference interval for natural killer cell activity through flow cytometry and its clinical application in the diagnosis of hemophagocytic lymphohistiocytosis
Authors: CHUNG H. J. , PARK C. J. , LIM J. H. , JANG S. , CHI H. S. , IM H. J. , SEO J. J.
Published: July 2009

Recently, the Histiocyte Society revised the diagnostic criteria for hemophagocytic lymphohistiocytosis (HLH) to include low or absent natural killer (NK) cell activity, according to local laboratory reference. The aim of this study was to establish reference interval for functional NK‐cell activity in 63 healthy Korean individuals using a flow‐cytometric assay. We used peripheral blood mononuclear cells (PBMCs) as effector cells and Fluorescein isothiocyanate‐labeled K562 cells as target cells. NK‐cell activity was calculated using the following equation: NK‐cell activity (%) = (test lysis − spontaneous lysis) × 100/(maximum lysis − spontaneous lysis). NK‐cell activity was analyzed in 13 known HLH patients and 16 suspected non‐HLH patients using a flow‐cytometric assay. The mean (±SD) cytotoxicity of PBMCs from healthy individuals was 20.9 ± 5.3% and the reference interval was 11.8–31.9%. The mean NK‐cell activity of HLH patients (8.3 ± 8.9%) was significantly lower (P = 0.001) than that of non‐HLH patients (20.1 ± 7.8%). The sequential changes in NK‐cell activity in the HLH group corresponded to clinical and laboratory findings following treatment. We successfully developed a functional NK‐cell activity test for use in the clinical laboratory and obtained a reference interval of NK‐cell activity from healthy donors. This assay, and associated reference interval, was used to analyze 30 clinically relevant specimens and the results were shown to be well correlated.
Single Cell Analysis of Complex Thymus Stromal Cell Populations: Rapid Thymic Epithelia Preparation Characterizes Radiation Injury
Authors: Williams Kirsten M. , Mella Heather , Lucas Philip J. , Williams Joy A. , Telford William , Gress Ronald E.
Published: July 2009

Thymic epithelial cells (TECs) and dendritic cells are essential for the maintenance of thymopoiesis. Because these stromal elements define the progenitor niche, provide critical survival signals and growth factors, and direct positive and negative selection, detailed study of these populations is necessary to understand important elements for thymic renewal after cytotoxic injury. Study of TEC is currently hindered by lengthy enzymatic separation techniques with decreased viability. We present a new rapid separation technique that yields consistent viable TEC numbers in a quarter of the prior preparation time. Using this new procedure, we identify changes in stromal populations following total body irradiation (TBI). By flow cytometry, we show that TBI significantly depletes UEA+ medullary TEC, while sparing Ly51+ CD45− cells. Further characterization of the Ly51+ subset reveals enrichment of fibroblasts (CD45− Ly51+ MHCII−), while cortical TECs (CD45− Ly51+ MHCII+) were markedly reduced. Dendritic cells (CD11c+ CD45+) were also decreased following TBI. These data suggest that cytotoxic preparative regimens may impair thymic renewal by reducing critical populations of cortical and medullary TEC, and that such thymic damage can be assessed by this new rapid separation technique, thereby providing a means of assessing optimal conditioning pretransplant for enhancing thymic‐dependent immune reconstitution posttransplant.
New single nucleotide polymorphisms in Alectoris identified using chicken genome information allow Alectoris introgression detection
Authors: SEVANE N. , CORTÉS O. , GARCÍA D. , CAÑÓN J. , DUNNER S.
Published: July 2009

Using the chicken genome, 114 polymorphisms (109 SNPs and 5 INDELs) were identified in the Alectoris genus by polymerase chain reaction–single strand conformation polymorphism. Using these, a panel of SNPs is described, which allows easy detection of introgression of Alectoris chukar in wild Alectoris rufa populations, when used with a primer extension protocol. The selected polymorphisms were genotyped and their allelic frequencies estimated on 98 A. rufa partridges sampled from nonrestocking Spanish areas, and 63 A. chukar partridges from Greek and Spanish farms. Power calculations to determine an optimum subset of markers for a given significance level were performed.
A Welfare Trap? The Duration and Dynamics of Social Assistance Use among Lone Mothers in Canada
Authors: COOKE MARTIN
Published: July 2009

À la fin des années 1990, la politique de l'aide sociale canadienne s'est transformée, pour se concentrer sur la diminution de la «dépendance» ou de l'aide sociale à long terme. En utilisant des données de l'Enquête sur la dynamique du travail et du revenu (1996–2001) et l'analyse historique des événements, l'auteur étudie la durée de l'aide sociale chez les mères monoparentales et autres chefs de ménage. Ses résultats montrent que l'instruction des mères monoparentales et leur expérience du marché du travail constituaient des prédicteurs moins importants de la durée de l'aide sociale que leur histoire conjugale. Quoique les prestations qu'elles recevaient duraient généralement peu de temps, l'auteur a trouvé la preuve d'une dépendance néfaste, ou du «piège de l'aide sociale», après un contrôle de l'hétérogénéité non observée. C'est un exemple démontrant que recevoir de l'aide sociale est non seulement le résultat de trajectoires de vie particulières, mais façonne aussi la vie.

In the late 1990s, the Canadian social assistance policy changed to focus on reducing “dependency” or long‐term receipt. Using data from the Survey of Labour and Income Dynamics (1996–2001) and event history models, we investigate the duration of social assistance receipt for lone mothers and other household heads. We find that lone mothers' education and labor force experience were less important predictors for their duration on social assistance than their previous marital history. Although receipt was generally short term, we find evidence of negative duration dependence, or a “welfare trap,” after controlling for unobserved heterogeneity. This indicates one way in which a welfare receipt is not only the result of particular life course trajectories but also shapes lives.
Policy Change and the Politics of Ideas: The Emergence of the Canada/Quebec Pension Plans
Authors: BABICH KRISTINA , BÉLAND DANIEL
Published: July 2009

Insistant sur l'impact direct des idées sur le changement politique, les auteurs se penchent sur l'adoption du Régime de rentes du Québec (RRQ) et du Régime de pensions du Canada (RPC) de 1965, en examinant deux questions étroitement liées: 1) Pourquoi le gouvernement fédéral a‐t‐il décidé de créer au milieu des années 1960 un système public de pension proportionnel aux revenus, en plus du Programme de la sécurité de la vieillesse alors en vigueur? et 2) Pourquoi ce nouveau système présente‐t‐il un taux de remplacement plus élevé que celui proposé initialement, de même qu'un régime différent pour le Québec? De manière à répondre à ces deux questions, les auteurs analysent les débats menant à l'adoption du RRQ et du RPC.

Stressing the direct impact of ideas on policy change, this article explores the adoption of the Canada and Quebec Pension Plans (C/QPP) in 1965 by addressing two closely related questions: in the mid‐1960s: why did the federal government decide to create an earnings‐related public pension system on top of the existing Old Age Security program? Second, why did that new system feature a replacement rate higher than initially proposed as well as a separate scheme for the province of Quebec? In order to answer these two questions, the article analyzes the debates leading to the enactment of the C/QPP.
A New Fast Ray Tracing Tool for High-Precision Simulation of Heliostat Fields
Authors: Belhomme B. , Pitz-Paal R. , Schwarzbözl P. , Ulmer S.
Published: July 2009

A completely new ray tracing software has been developed at the German Aerospace Center. The main purpose of this software is the flux density simulation of heliostat fields with a very high accuracy in a small amount of computation time. The software is primarily designed to process real sun shape distributions and real highly resolved heliostat geometry data, which means a data set of normal vectors of the entire reflecting surface of each heliostat in the field. Specific receiver and secondary concentrator models, as well as models of objects that are shadowing the heliostat field, can be implemented by the user and be linked to the simulation software subsequently. The specific architecture of the software enables the provision of other powerful simulation environments with precise flux density simulation data for the purpose of entire plant simulations. The software was validated through a severe comparison with measured flux density distributions. The simulation results show very good accordance with the measured results.
Optimization of Solar Photovoltaic Fields
Authors: Weinstock D. , Appelbaum J.
Published: July 2009

The design of stationary and single axes tracking collectors in a field consisting of rows of collectors involves relationships between the field and collector parameters and solar radiation data. In addition, shading and masking of adjacent rows affect the collector deployment of the field by decreasing the incident energy on the collector plane. The use of many rows, densely deployed in a given field, increases the field incident energy but also increases the shading. Therefore, there is an optimal deployment of the collectors in the field yielding, for example, maximum energy, minimum required field area, or other objectives. For photovoltaic collectors, the output energy depends on the module efficiency, the solar cell operating temperature, and on the scheme of the electrically interconnected modules. Series interconnection between the photovoltaic modules may have a significant effect on the output energy of the solar plant in event of shading. The present article deals with the optimal design of photovoltaic solar fields for stationary and single axes tracking collectors to obtain maximum annual output energy.
Reactive Pellets for Improved Solar Hydrogen Production Based on Sodium Manganese Ferrite Thermochemical Cycle
Authors: Alvani Carlo , Bellusci Mariangela , La Barbera Aurelio , Padella Franco , Pentimalli Marzia , Seralessandri Luca , Varsano Francesca
Published: July 2009

Hydrogen production by water-splitting thermochemical cycle based on manganese ferrite/sodium carbonate reactive system is reported. Two different preparation procedures for manganese ferrite/sodium carbonate mixture were adopted and compared in terms of material capability to cyclical hydrogen production. According to the first procedure, conventionally synthesized manganese ferrite, i.e., high temperature (1250°C) heating in Ar of carbonate/oxide precursors, was mixed with sodium carbonate. The blend was tested inside a temperature programed desorption reactor using a cyclical hydrogen production/material regeneration scheme. After a few cycles, the mixture resulted rapidly passivated and unable to further produce hydrogen. An innovative method that avoids the high temperature synthesis of manganese ferrite is presented. This procedure consists in a set of consecutive thermal treatments of a manganese carbonate/sodium carbonate/iron oxide mixture in different environments (inert, oxidative, and reducing) at temperatures not exceeding 750°C. Such material, whose observed chemical composition consists of manganese ferrite and sodium carbonate in stoichiometric amounts, is able to evolve hydrogen during 25 consecutive water-splitting cycles, with a small decrease in cyclical production efficiency.
Solar Flash Desalination Under Hydrostatically Sustained Vacuum
Authors: Abutayeh Mohammad , Goswami D. Yogi
Published: July 2009

A new desalination scheme has been proposed. The system consists of a saline water tank, a concentrated brine tank, and a fresh water tank placed on ground level plus an evaporator and a condenser located several meters above the ground. The evaporator-condenser assembly, or flash chamber, is initially filled with saline water that later drops by gravity, creating a vacuum above the water surface in the unit without a vacuum pump. The vacuum is maintained by the internal hydrostatic pressure balanced by the atmospheric pressure. The ground tanks are open to the atmosphere, while the flash chamber is insulated and sealed to retain both heat and vacuum. A theoretical simulation of the proposed model was carried out using a detailed model built by employing the fundamental physical and thermodynamic relationships to describe the process and was complimented by reliable empirical correlations to estimate the physical properties of the involved species and the operational parameters of the proposed system. The simulation results show that running the system at higher flash temperatures with a fixed flash chamber size will result in faster vacuum erosion leading to less overall evaporation.
An Assessment on Simple Modeling Approaches to the Electric Behavior of Two CIS PV Modules in a Sunny Climate
Authors: Nofuentes G. , Fuentes M. , Aguilera J. , Muñoz J. V.
Published: July 2009

Predicting both copper indium diselenide (CIS) module and generator performance outdoors is a crucial issue for designers and installers who use this technology. Three simple methods addressed to predict the behavior of two modules of this technology in a sunny climate have been empirically tried. A 12-month test and measurement campaign carried out using two calibrated CIS photovoltaic (PV) modules in the city of Jaén (Spain, latitude 38°N, longitude 3°W) has provided the necessary empirical data. Results show that the electric behavior of these CIS PV modules may be described with adequate accuracy—for PV engineering in sunny sites—assuming the fill factor remains constant through operation while short-circuit current and open circuit voltage vary linearly with incident global irradiance and cell temperature, respectively. Further, degradation has been of no concern—otherwise, this would have invalidated the above conclusions—as it stems from the small difference between the results of the initial calibration and those of a recalibration of the modules after their outdoor exposure. Additionally, high values of the module performance ratio lead to the same conclusion.
Solar Thermal Electrolytic Process for the Production of Zn From ZnO: An Ionic Conductivity Study
Authors: Venstrom L. , Krueger K. , Leonard N. , Tomlinson B. , Duncan S. , Palumbo R. D.
Published: July 2009

The ionic conductivities of mixtures of ZnO in Na3AlF6 and in xCaF2–yNa3AlF6 mixtures were established with a swept-sine measurement technique. A millivolt sinusoidal voltage at frequencies from 1000 Hz to 25,000 Hz was impressed on a system containing the electrolytes. The system’s frequency response was used to establish the conductivities. The influence of these conductivities on the potential of a solar thermal electrolytic process was evaluated using two process performance parameters: the back-work ratio and the fraction of minimum solar thermal energy required to drive the metal production reaction. We found the conductivity of mixtures of ZnO–Na3AlF6 to be independent of the concentration of ZnO for weight percentages of ZnO from 0.5% to 5%. For temperatures 1240–1325 K the conductivity is close to that of pure Na3AlF6, 3±0.5 Ω−1 cm−1. At temperatures from 1350 K to 1425 K it jumps to 6±0.5 Ω−1 cm−1 When CaF2 is added to the mixture, the electrolyte’s conductivity drops. We thus expect that calcium cations are not present to any important extent in the electrolyte. When CaF2 is part of the chemical system, the concentration of ZnO can have a measurable impact on the electrolyte’s conductivity. Combining the conductivity results with the two solar process performance parameters illustrates the importance of operating the solar process at low current densities when the temperature range is 1200–1500 K. The results further suggest that one should consider studying the electrolytic process at 1800 K.
What is the Best Solution to Improve Thermal Performance of Storage Tanks With Immersed Heat Exchangers: Baffles or a Divided Tank?
Authors: Wade Aaron D. , Davidson Jane H. , Haltiwanger Julia F.
Published: July 2009

Prior studies of indirect water storage tanks that employ an immersed heat exchanger to discharge the stored energy identified two potential methods of improving the rate of energy extraction: (1) an internal baffle to increase the velocity across the heat exchanger and (2) a divided storage compartment to achieve thermal stratification. The relative benefits of the two options are compared and recommendations for implementation are provided based in part on measurements in a 350 l tank with a 10 m long, 0.3 m2 coiled tubular heat exchanger.
Comparative Evaluation of Maximum Power Point Tracking Methods for Photovoltaic Systems
Authors: Azevedo G. M. S. , Cavalcanti M. C. , Oliveira K. C. , Neves F. A. S. , Lins Z. D.
Published: July 2009

This paper presents a study of two maximum power point tracking methods for grid connected photovoltaic systems. The best operation conditions for the perturbation and observation and the incremental conductance methods are investigated in order to identify the efficiency performances of these most popular maximum power point tracking methods for photovoltaic systems. Improvements of these methods can be obtained with the best adjustment of the sampling rate and the perturbation size, both in accordance with the converter dynamics. Practical aspects about the incremental conductance method are discussed, and some modifications are proposed to overcome its problems. A procedure to determine the parameters is explained. This procedure helps to identify which method is better suited for grid connected photovoltaic systems with only one conversion stage. The methods’ influences on the quality of the currents injected in the grid are evaluated and compared. The performance improvement achieved with the choice of the best parameters is proved by means of simulation and experimental results performed on a low power test system. The simulation results have been obtained by modeling a photovoltaic system in MATLAB. A simplified model was used that employs only parameters of interest and therefore decreases simulation time. Experimental results corresponding to the operation of a grid connected photovoltaic converter controlled with a digital signal processor have been obtained.
Cantonese tone recognition with enhanced temporal periodicity cues
Authors: Yuan Meng , Lee Tan , Yuen Kevin C. P. , Soli Sigfrid D. , van Hasselt Charles A. , Tong Michael C. F.
Published: July 2009

This study investigated the contributions of temporal periodicity cues and the effectiveness of enhancing these cues for Cantonese tone recognition in noise. A multichannel noise-excited vocoder was used to simulate speech processing in cochlear implants. Ten normal-hearing listeners were tested. Temporal envelope and periodicity cues (TEPCs) below 500Hz were extracted from four frequency bands: 60–500, 500–1000, 1000–2000, and 2000–4000Hz. The test stimuli were obtained by combining TEPC-modulated noise signals from individual bands. For periodicity enhancement, temporal fluctuations in the range 20–500Hz were replaced by a sinusoid with frequency equal to the fundamental frequency of original speech. Tone identification experiments were carried out using disyllabic word carriers. Results showed that TEPCs from the two high-frequency bands were more important for tone identification than TEPCs from the low-frequency bands. The use of periodicity-enhanced TEPCs led to consistent improvement of tone identification accuracy. The improvement was more significant at low signal-to-noise ratios, and more noticeable for female than for male voices. Analysis of error distributions showed that the enhancement method reduced tone identification errors and did not show any negative effect on the recognition of segmental structures.
Impact of meteorological conditions on noise propagation from freeway corridors
Authors: Ovenden N. C. , Shaffer S. R. , Fernando H. J. S.
Published: July 2009

This paper examines the impact of meteorological conditions on the propagation of vehicular noise from urban freeways. A parabolic equation model coupled to an analytical Green’s function solution close to the source field is used to compute the refracted sound field up to half a mile from the freeway to predict the noise exposure of residential areas nearby. The model was used in conjunction with meteorological and sound-level measurements taken at two freeway sites over the course of four days in Phoenix, AZ. From the data collected, three test cases of varying levels of atmospheric stratification and wind shear are presented and discussed. The model demonstrates that atmospheric effects are able to raise sound levels by 10–20dB at significant distances away from the highway, causing violations of acceptable limits imposed by the Federal Highway Administration in residential areas that are normally in compliance.
Modeling perceptual effects of reverberation on stereophonic sound reproduction in rooms
Authors: Zarouchas Thomas , Mourjopoulos John
Published: July 2009

The proposed model derives time-frequency maps to estimate perceived alterations due to reverberation in stereo audio signals reproduced in rooms. These alterations relate to monaural masking due to reverberant decay, derived via a computational auditory masking model and to inter-channel cues for the formation of the spatial position of the aural objects, derived via an inter-channel cue mapping module. The maps illustrate in detail the varying nature of the perceptually-relevant alterations due to room reverberation. Quantitative metrics are also introduced which were found to be proportional to reverberation interference, to room-reverberation time and to depend on the specific audio signal. A statistical approach classifies room response properties via their histogram distributions. Corresponding distributions were also applied to the proposed signal-dependent perceptual maps. Such distributions were found to be useful for interpreting the perceived alterations with different kinds of signals, such as music or speech.
Masking release for words in amplitude-modulated noise as a function of modulation rate and task
Authors: Buss Emily , Whittle Lisa N. , Grose John H. , Hall Joseph W.
Published: July 2009

For normal-hearing listeners, masked speech recognition can improve with the introduction of masker amplitude modulation. The present experiments tested the hypothesis that this masking release is due in part to an interaction between the temporal distribution of cues necessary to perform the task and the probability of those cues temporally coinciding with masker modulation minima. Stimuli were monosyllabic words masked by speech-shaped noise, and masker modulation was introduced via multiplication with a raised sinusoid of 2.5–40 Hz. Tasks included detection, three-alternative forced-choice identification, and open-set identification. Overall, there was more masking release associated with the closed than the open-set tasks. The best rate of modulation also differed as a function of task; whereas low modulation rates were associated with best performance for the detection and three-alternative identification tasks, performance improved with modulation rate in the open-set task. This task-by-rate interaction was also observed when amplitude-modulated speech was presented in a steady masker, and for low- and high-pass filtered speech presented in modulated noise. These results were interpreted as showing that the optimal rate of amplitude modulation depends on the temporal distribution of speech cues and the information required to perform a particular task.
Pitch discrimination interference between binaural and monaural or diotic pitches
Authors: Gockel Hedwig E. , Carlyon Robert P. , Plack Christopher J.
Published: July 2009

Fundamental frequency (F0) discrimination between two sequentially presented complex (target) tones can be impaired in the presence of an additional complex tone (the interferer) even when filtered into a remote spectral region [Gockel, H., et al. (2004). J. Acoust. Soc. Am. 116, 1092–1104]. This “pitch discrimination interference” (PDI) is greatest when the interferer and target have similar F0s. The present study measured PDI using monaural or diotic complex-tone interferers and “Huggins pitch” or diotic complex-tone targets. The first experiment showed that listeners hear a “complex Huggins pitch” (CHP), approximately corresponding to F0, when multiple phase transitions at harmonics of (but not at) F0 are present. The accuracy of pitch matches to the CHP was similar to that for an equally loud diotic tone complex presented in noise. The second experiment showed that PDI can occur when the target is a CHP while the interferer is a diotic or monaural complex tone. In a third experiment, similar amounts of PDI were observed for CHP targets and for loudness-matched diotic complex-tone targets. Thus, a conventional complex tone and CHP appear to be processed in common at the stage where PDI occurs.
Temporal and spatial coherence of sound at 250 Hz and 1659 km in the Pacific Ocean: Demonstrating internal waves and deterministic effects explain observations
Authors: Spiesberger John L.
Published: July 2009

The hypothesis tested is that internal gravity waves explain temporal and spatial coherences of sound at 1659 km in the Pacific Ocean for a signal at 250 Hz and a pulse resolution of 0.02 s. From data collected with a towed array, the measured probability that coherence time is 1.8 min or longer is 0.8. Using a parabolic approximation for the acoustic wave equation with sound speeds fluctuating from internal waves, a Monte-Carlo model yields coherence time of 1.8 min or more with probability of 0.9. For spatial coherence, two subsections of the array are compared that are separated by 142 and 370 m in directions perpendicular and parallel to the geodesic, respectively. Measured coherence is 0.54. This is statistically consistent with the modeled 95% confidence interval of [0.52, 0.76]. The difference of 370 m parallel to the section causes spatial coherence to degrade deterministically by a larger amount than the effect of internal waves acting on the 142 m separation perpendicular to the section. The models are run without any tuning with data.
Testing the binaural equal-loudness-ratio hypothesis with hearing-impaired listeners
Authors: Marozeau Jeremy , Florentine Mary
Published: July 2009

The primary purpose of the present experiment was to test whether the binaural equal-loudness-ratio hypothesis (i.e., the loudness ratio between monaural and binaural tones presented at the same Sound Pressure Level, SPL, is independent of SPL) holds for hearing-impaired listeners with bilaterally symmetrical hearing losses. The outcome of this experiment provided a theoretical construct for modeling loudness-growth functions. A cross-modality matching task between string length and tones was used to measure three loudness functions for eight listeners: two monaural (left and right) and one binaural. A multiple linear regression was performed to test the significance of presentation mode (monaural vs binaural and left vs right), level, and their interaction. Results indicate that monaural loudness functions differ between the ears of two listeners. The interaction between presentation mode (binaural/monaural) and level was significant for one listener. Although significant, these differences were quite small. Generally, the binaural equal-loudness-ratio hypothesis appears to hold for hearing-impaired listeners. These data also indicate that loudness-growth functions in two ears of an individual are more similar than loudness-growth functions in ears from different listeners. Finally, it is demonstrated that loudness-growth functions can be constructed for individual listeners from binaural level difference for equal-loudness data.
Optimal electrode selection for multi-channel electroencephalogram based detection of auditory steady-state responses
Authors: Van Dun Bram , Wouters Jan , Moonen Marc
Published: July 2009

Auditory steady-state responses (ASSRs) are used for hearing threshold estimation at audiometric frequencies. Hearing impaired newborns, in particular, benefit from this technique as it allows for a more precise diagnosis than traditional techniques, and a hearing aid can be better fitted at an early age. However, measurement duration of current single-channel techniques is still too long for clinical widespread use. This paper evaluates the practical performance of a multi-channel electroencephalogram (EEG) processing strategy based on a detection theory approach. A minimum electrode set is determined for ASSRs with frequencies between 80 and 110Hz using eight-channel EEG measurements of ten normal-hearing adults. This set provides a near-optimal hearing threshold estimate for all subjects and improves response detection significantly for EEG data with numerous artifacts. Multi-channel processing does not significantly improve response detection for EEG data with few artifacts. In this case, best response detection is obtained when noise-weighted averaging is applied on single-channel data. The same test setup (eight channels, ten normal-hearing subjects) is also used to determine a minimum electrode setup for 10-Hz ASSRs. This configuration allows to record near-optimal signal-to-noise ratios for 80% of subjects.
Acoustic profiles of distinct emotional expressions in laughter
Authors: Szameitat Diana P. , Alter Kai , Szameitat André J. , Wildgruber Dirk , Sterr Annette , Darwin Chris J.
Published: July 2009

Although listeners are able to decode the underlying emotions embedded in acoustical laughter sounds, little is known about the acoustical cues that differentiate between the emotions. This study investigated the acoustical correlates of laughter expressing four different emotions: joy, tickling, taunting, and schadenfreude. Analysis of 43 acoustic parameters showed that the four emotions could be accurately discriminated on the basis of a small parameter set. Vowel quality contributed only minimally to emotional differentiation whereas prosodic parameters were more effective. Emotions are expressed by similar prosodic parameters in both laughter and speech.
Policy discourse, people’s internal frames, and declared aircraft noise annoyance: An application of Q-methodology
Authors: Kroesen Maarten , Bröer Christian
Published: July 2009

Aircraft noise annoyance is studied extensively, but often without an explicit theoretical framework. In this article, a social approach for noise annoyance is proposed. The idea that aircraft noise is meaningful to people within a socially produced discourse is assumed and tested. More particularly, it is expected that the noise policy discourse influences people’s assessment of aircraft noise. To this end, Q-methodology is used, which, to the best of the authors’ knowledge, has not been used for aircraft noise annoyance so far. Through factor analysis five distinct frames are revealed: “Long live aviation!,” “aviation: an ecological threat,” “aviation and the environment: a solvable problem,” “aircraft noise: not a problem,” and “aviation: a local problem.” It is shown that the former three frames are clearly related to the policy discourse. Based on this observation it is argued that policy making is a possible mechanism through which the sound of aircraft is turned into annoyance. In addition, it is concluded that the experience of aircraft noise and, in particular, noise annoyance is part of coherent frames of mind, which consist of mutually reinforcing positions and include non-acoustical factors.
Left hand finger force in violin playing: Tempo, loudness, and finger differences
Authors: Kinoshita Hiroshi , Obata Satoshi
Published: July 2009

A three-dimensional force transducer was installed in the neck of a violin under the A string at the D5 position in order to study the force with which the violinist clamps the string against the fingerboard under normal playing conditions. Violinists performed repetitive sequences of open A- and fingered D-tones using the ring finger at tempi of 1, 2, 4, 8, and 16 notes/s at mezzo-forte. At selected tempi, the effects of dynamic level and the use of different fingers were investigated as well. The force profiles were clearly dependent on tempo and dynamic level. At slow tempi, the force profiles were characterized by an initial pulse followed by a level force to the end of the finger contact period. At tempi higher than 2 Hz, only pulsed profiles were observed. The peak force exceeded 4.5 N at 1 and 2 Hz and decreased to 1.7 N at 16 Hz. All force and impulse values were lower at softer dynamic levels, and when using the ring or little finger compared to the index finger.
An efficient code for environmental sound classification
Authors: Arora Raman , Lutfi Robert A.
Published: July 2009

An efficient code for classifying environmental sounds is described that exploits a recent significant advance in signal processing known as compressed sensing (CS) [cf.Donoho, D. (2006). IEEE Trans. Inf. Theory 52, 1289–1306]. CS involves a novel approach to sampling in which the salient information in signals is recovered from the projection onto a small set of random basis functions. The advantage of the random basis over traditional Fourier or wavelet representations is that it allows accurate classification at low target-to-interference ratios based on few samples and little or no prior information about signals.
Sequential stream segregation using temporal periodicity cues in cochlear implant recipients
Authors: Hong Robert S. , Turner Christopher W.
Published: July 2009

Sequential stream segregation involves the ability of a listener to perceptually segregate two rapidly alternating sounds into different perceptual streams. By studying auditory streaming in cochlear implants (CIs), one can obtain a better understanding of the cues that CI recipients can use to segregate different sound sources, which may have relevance to such everyday activities as the understanding of speech in background noise. This study focuses on the ability of CI users to use temporal periodicity cues to perform auditory stream segregation. A rhythmic discrimination task involving sequences of alternating amplitude-modulated (AM) noises is used. The results suggest that most CI users can stream AM noise bursts at relatively low modulation frequencies (near 80 Hz AM), but that this ability diminishes at higher modulation frequencies. Additionally, the ability of CI users to perform streaming using temporal periodicity cues appears to be comparable to that of normal-hearing listeners. These results imply that CI subjects may in certain contexts (i.e., when the talker has a low fundamental frequency voice) be able to use temporal periodicity cues to segregate and thus understand the voices of competing talkers.
Green’s function approximation from cross-correlation of active sources in the ocean
Authors: Brooks Laura A. , Gerstoft Peter
Published: July 2009

Green’s function approximation via ocean noise cross-correlation, referred to here as ocean acoustic interferometry, has 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.
Amplifying effect of a release mechanism for fast adaptation in the hair bundle
Authors: Sul Bora , Iwasa Kuni H.
Published: July 2009

A “release” mechanism, which has been experimentally observed as the fast component in the hair bundle’s response to mechanical stimulation, appears similar to common mechanical relaxation with a damping effect. This observation is puzzling because such a response is expected to have an amplifying role in the mechanoelectrical transduction process in hair cells. Here it is shown that a release mechanism can indeed have a role in amplification, if it is associated with negative stiffness due to the gating of the mechonoelectric transducer channel.
Shaping of a system’s frequency response using an array of subordinate oscillators
Authors: Vignola Joseph F. , Judge John A. , Kurdila Andrew J.
Published: July 2009

The frequency response of an oscillating structure can be tailored by attaching one or more subordinate oscillators. This paper shows how the magnitude and phase of the frequency response can be deliberately shaped by prescribing the distributions of the dynamic properties in an array of such subordinate oscillators. Exact analytic governing equations of motion are derived for the coupled system composed of the primary system and the subordinate array. For a relatively small number (<100) of attached oscillators whose total mass is small (<1%) relative to the primary structure, it is possible to engineer frequency-response functions of the primary oscillator to have, for example, nearly linear phase or constant amplitude over a frequency band of interest. The frequency range over which response shaping is achieved is determined by the band of the attached oscillators. It is shown that the common analytic methodology for designing a dynamic vibration absorber represents the limiting case of a single oscillator in the subordinate set. Moreover, increasing the number of subordinate oscillators (without increasing the total added mass) offers a number of advantages in reshaping the dominant system’s frequency response.
Asynchronous control of vortex-induced acoustic cavity resonance using imbedded piezo-electric actuators
Authors: Zhang M. M. , Cheng L. , Zhou Y.
Published: July 2009

This paper presents an experimental investigation of the control of a vortex-induced acoustic cavity resonance from flow over a bluff body using embedded piezo-ceramic actuators in order to alter the resonant flow-acoustic interactions. The action of the actuators was asynchronous. Experiments were mainly conducted at the flow velocity of acoustic resonance, where the vortex shedding frequency from the upstream bluff body approached the frequency of the first acoustic mode of two downstream cavities. The fluctuating acoustic pressure was measured using a microphone. The perturbed flow field around the bluff body was monitored using two single hot wire anemometers and one X-wire. It was found that the induced transverse vibrations were effective to reduce the acoustic resonance. The cavity sound pressure level at resonance was reduced by 8.2dB in presence of actuation. The physics behind the control mechanism is discussed.
Interference suppression for code-division multiple-access communications in an underwater acoustic channel
Authors: Yang T. C. , Yang Wen-Bin
Published: July 2009

In a code-division multiple-access communications network, the signal from a nearby user often creates a strong interference for the signal from a distant user. This is known as the near-far problem. Power control of source levels is ineffective in an underwater acoustic channel due to the slow sound speed. Interference rejection based on code orthogonality is ineffective using matched-filter processing due to the fact that multipath arrivals effectively destroy the code orthogonality and that the signal arrival times between different users are not synchronized. An algorithm, called hyperspace cancellation by coordinate zeroing, is used in this paper to remove/suppress interference. Using a fast Walsh–Hadamard transform (FWHT) based on the interferer’s code sequence, the interference signal is enhanced and removed by coordinate zeroing. The residual signal is transformed back using an inverse FWHT. The filtered data, with the interference signal largely removed, are processed using the desired signal code sequence. Two methods previously developed for direct-sequence spread-spectrum communications in an underwater channel are used to extract the transmitted symbols. Low bit error rate (<10−2) is found with the at-sea data for signal-to-interference ratio as low as −8 to −11 dB.
Analysis of the temporal structure of fish echoes using the dolphin broadband sonar signal
Authors: Matsuo Ikuo , Imaizumi Tomohito , Akamatsu Tomonari , Furusawa Masahiko , Nishimori Yasushi
Published: July 2009

Behavioral experiments indicate that dolphins detect and discriminate prey targets through echolocating broadband sonar signals. The fish echo contains components from multiple reflections, including those from the swim bladder and other organs, and can be used for the identification of fish species and the estimation of fish abundance. In this paper, temporal structures were extracted from fish echoes using the cross-correlation function and the lowpass filter. First, the echo was measured from an anesthetized fish in a water tank. The number, reflector intensity, and echo duration were shown to be dependent on the species, individual, and orientation of the fish. In particular, the echo duration provided useful information on the fish body height and for species identification. Second, the echo was measured from the live fish suspended by nylon monofilament lines in the open sea. It was shown that this duration could be estimated regardless of whether or not the fish were moving.