Sublinear quasiconformality and the large-scale geometry of Heintze groups

This article analyzes sublinearly quasisymmetric homeo-morphisms (generalized quasisymmetric mappings), and draws applications to the sublinear large-scale geometry of negatively curved groups and spaces. It is proven that those homeomorphisms lack analytical properties but preserve a conformal dimension and appropriate function spaces, distinguishing certain (nonsymmetric) Riemannian negatively curved homogeneous spaces, and Fuchsian buildings, up to sublinearly biLipschitz equivalence (generalized quasiisometry).Comment: v1->v2: shortened, revised. Lemma 2.3 and definition of Cdim corrected. Proof of main theorem simplified. Figure 4 adde

Phonemes and Syllables in Speech Perception: size of the attentional focus in French.

A study by Pitt and Samuel (1990) found that English speakers could narrowly focus attention onto a precise phonemic position inside spoken words [1]. This led the authors to argue that the phoneme, rather than the syllable, is the primary unit of speech perception. Other evidence, obtained with a syllable detection paradigm, has been put forward to propose that the syllable is the unit of perception; yet, these experiments were ran with French speakers [2]. In the present study, we adapted Pitt & Samuel's phoneme detection experiment to French and found that French subjects behave exactly like English subjects: they too can focus attention on a precise phoneme. To explain both this result and the established sensitivity to the syllabic structure, we propose that the perceptual system automatically parses the speech signal into a syllabically-structured phonological representation

Word recognition: do we need phonological representations?

Under what format(s) are spoken words memorized by the brain? Are word forms stored as abstract phonological representations? Or rather, are they stored as detailed acoustic-phonetic representations? (For example as a set of acoustic exemplars associated with each word). We present a series of experiments whose results point to the existence of prelexical phonological processes in word recognition and suggest that spoken words are accessed using a phonological code

Neuronal bases of structural coherence in contemporary dance observation

The neuronal processes underlying dance observation have been the focus of an increasing number of brain imaging studies over the past decade. However, the existing literature mainly dealt with effects of motor and visual expertise, whereas the neural and cognitive mechanisms that underlie the interpretation of dance choreographies remained unexplored. Hence, much attention has been given to the Action Observation Network (AON) whereas the role of other potentially relevant neuro-cognitive mechanisms such as mentalizing (theory of mind) or language (narrative comprehension) in dance understanding is yet to be elucidated. We report the results of an fMRI study where the structural coherence of short contemporary dance choreographies was manipulated parametrically using the same taped movement material. Our participants were all trained dancers. The whole-brain analysis argues that the interpretation of structurally coherent dance phrases involves a subpart (Superior Parietal) of the AON as well as mentalizing regions in the dorsomedial Prefrontal Cortex. An ROI analysis based on a similar study using linguistic materials (Pallier et al. 2011) suggests that structural processing in language and dance might share certain neural mechanisms

Phonological representations and repetition priming

An ubiquitous phenomenon in psychology is the `repetition effect': a repeated stimulus is processed better on the second occurrence than on the first. Yet, what counts as a repetition? When a spoken word is repeated, is it the acoustic shape or the linguistic type that matters? In the present study, we contrasted the contribution of acoustic and phonological features by using participants with different linguistic backgrounds: they came from two populations sharing a common vocabulary (Catalan) yet possessing different phonemic systems. They performed a lexical decision task with lists containing words that were repeated verbatim, as well as words that were repeated with one phonetic feature changed. The feature changes were phonemic, i.e. linguistically relevant, for one population, but not for the other. The results revealed that the repetition effect was modulated by linguistic, not acoustic, similarity: it depended on the subjects' phonemic system

A limit on behavioral plasticity in speech perception.

It is well attested that we perceive speech through the filter of our native language: a classic example is that of Japanese listeners who cannot discriminate between the American /l/ and /r/ and identify both as their own /r/ phoneme (Goto, 1971). Studies in the laboratory have shown, however, that perception of non-native speech sounds can be learned through training (Lively, Pisoni, Yamada, & Tohkura, 1994). This is consistent with neurophysiological evidence showing considerable experience-dependent plasticity in the brain at the first levels of sensory processing (Edeline & Weinberger, 1993; Kraus, et al., 1995; Merzenich & Sameshima, 1993; Weinberger, 1993). Outside of the laboratory, however, the situation seems to differ: we here report a study involving Spanish-Catalan bilingual subjects who have had the best opportunities to learn a new contrast but did not do it. Our study demonstrates a striking lack of behavioral plasticity: early and extensive exposure to a second language is not sufficient to attain the ultimate phonological competence of native speakers

A destressing "deafness" in French?

French is a language in which accent is mandatory on the last syllable of every content word. In contrast, Spanish uses accent to distinguish different lexical items (e.g., b'ebe vs beb'e). Two population of subjects were tested on the same materials to study whether such linguistic differences have an impact on the perceptual capacities of listeners. In Experiment 1, using an ABX paradigm, we find that French Subjects have a surprising deficit compared to Spanish Subjects in making accent distinctions. In Experiment 2, we find that Spanish subjects cannot ignore irrelevant differences in accent in a phoneme-based ABX task, whereas French Subjects have no difficulty at all. In Experiment 3, we replicate the basic French finding, and find that Spanish subjects benefit from redundant accent information even when phonemic information alone is sufficient to perform the task. In our final Experiment 4, we show that French subjects can hear the acoustic correlates of accent; their problem seem to arise at the level of short term memory. Implications for language-specific processing and acquisition are discussed

Sublinear quasiconformality and the large-scale geometry of Heintze groups

v1->v2: shortened, revised. Lemma 2.3 and definition of Cdim corrected. Proof of main theorem simplified. Figure 4 added.This article analyzes sublinearly quasisymmetric homeo-morphisms (generalized quasisymmetric mappings), and draws applications to the sublinear large-scale geometry of negatively curved groups and spaces. It is proven that those homeomorphisms lack analytical properties but preserve a conformal dimension and appropriate function spaces, distinguishing certain (nonsymmetric) Riemannian negatively curved homogeneous spaces, and Fuchsian buildings, up to sublinearly biLipschitz equivalence (generalized quasiisometry)

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Situation des SCD à partir d\u27une enquête de l\u27IGB (2004) afin d\u27apprécier l\u27évolution des organisations documentaires des universités