Dichotic integration of acoustic-phonetic information: Competition from extraneous formants increases the effect of second-formant attenuation on intelligibility

Differences in ear of presentation and level do not prevent effective integration of concurrent speech cues such as formant frequencies. For example, presenting the higher formants of a consonant-vowel syllable in the opposite ear to the first formant protects them from upward spread of masking, allowing them to remain effective speech cues even after substantial attenuation. This study used three-formant (F1+F2+F3) analogues of natural sentences and extended the approach to include competitive conditions. Target formants were presented dichotically (F1+F3; F2), either alone or accompanied by an extraneous competitor for F2 (i.e., F1±F2C+F3; F2) that listeners must reject to optimize recognition. F2C was created by inverting the F2 frequency contour and using the F2 amplitude contour without attenuation. In experiment 1, F2C was always absent and intelligibility was unaffected until F2 attenuation exceeded 30 dB; F2 still provided useful information at 48-dB attenuation. In experiment 2, attenuating F2 by 24 dB caused considerable loss of intelligibility when F2C was present, but had no effect in its absence. Factors likely to contribute to this interaction include informational masking from F2C acting to swamp the acoustic-phonetic information carried by F2, and interaural inhibition from F2C acting to reduce the effective level of F2

High-pressure cryogelation of nanosilica and surface properties of cryosilicas

Silica cryogels (cryosilicas) in a powder state were synthesized with different concentrations of fumed silica A-300 (CA-300 = 5-20 wt.%), sonicated in aqueous suspension, then frozen at -14 oC at different pressures in a high-pressure stainless steel reactor (a freezing bomb), and dried in air at room temperature. To analyze the effects of low temperature and high pressure, samples were also prepared at -14 oC or room temperature and standard pressure. The structural and adsorption properties of the powder materials were studied using nitrogen adsorption, high-resolution transmission electron microscopy, infrared spectroscopy, thermogravimetry, low-temperature 1H NMR spectroscopy and thermally stimulated depolarization current. The structural, textural, adsorption and relaxation characteristics of high-pressure cryogel hydrogels and related dried powders are strongly dependent on the silica content in aqueous suspensions frozen at 1, 450 or 1000 atmospheres and then dried. The largest changes are found with CA-300 = 20 wt.% which are analyzed with respect to the interfacial behavior of nonpolar, weakly polar and polar adsorbates using low temperature 1H NMR spectroscopy

Hemispheric Asymmetries in Speech Perception: Sense, Nonsense and Modulations

Background: The well-established left hemisphere specialisation for language processing has long been claimed to be based on a low-level auditory specialization for specific acoustic features in speech, particularly regarding 'rapid temporal processing'.Methodology: A novel analysis/synthesis technique was used to construct a variety of sounds based on simple sentences which could be manipulated in spectro-temporal complexity, and whether they were intelligible or not. All sounds consisted of two noise-excited spectral prominences (based on the lower two formants in the original speech) which could be static or varying in frequency and/or amplitude independently. Dynamically varying both acoustic features based on the same sentence led to intelligible speech but when either or both acoustic features were static, the stimuli were not intelligible. Using the frequency dynamics from one sentence with the amplitude dynamics of another led to unintelligible sounds of comparable spectro-temporal complexity to the intelligible ones. Positron emission tomography (PET) was used to compare which brain regions were active when participants listened to the different sounds.Conclusions: Neural activity to spectral and amplitude modulations sufficient to support speech intelligibility (without actually being intelligible) was seen bilaterally, with a right temporal lobe dominance. A left dominant response was seen only to intelligible sounds. It thus appears that the left hemisphere specialisation for speech is based on the linguistic properties of utterances, not on particular acoustic features

Rigorous Polynomial Approximation using Taylor Models in Coq

International audienceOne of the most common and practical ways of representing a real function on machines is by using a polynomial approximation. It is then important to properly handle the error introduced by such an approximation. The purpose of this work is to offer guaranteed error bounds for a specific kind of rigorous polynomial approximation called Taylor model. We carry out this work in the Coq proof assistant, with a special focus on genericity and efficiency for our implementation. We give an abstract interface for rigorous polynomial approximations, parameter- ized by the type of coefficients and the implementation of polynomials, and we instantiate this interface to the case of Taylor models with inter- val coefficients, while providing all the machinery for computing them. We compare the performances of our implementation in Coq with those of the Sollya tool, which contains an implementation of Taylor models written in C. This is a milestone in our long-term goal of providing fully formally proved and efficient Taylor models

Roadmap on Superoscillations

Superoscillations are band-limited functions with the counterintuitive property that they can vary arbitrarily faster than their fastest Fourier component, over arbitrarily long intervals. Modern studies originated in quantum theory, but there were anticipations in radar and optics. The mathematical understanding—still being explored—recognises that functions are extremely small where they superoscillate; this has implications for information theory. Applications to optical vortices, sub-wavelength microscopy and related areas of nanoscience are now moving from the theoretical and the demonstrative to the practical. This Roadmap surveys all these areas, providing background, current research, and anticipating future developments