Cascades in the dynamics of affine interval exchange transformations

We describe in this article the dynamics of a $1$-parameter family of affine interval exchange transformations. It amounts to studying the directional foliations of a particular affine surface, the Disco surface. We show that this family displays various dynamical behaviours: it is generically dynamically trivial, but for a Cantor set of parameters the leaves of the foliations accumulate to a (transversely) Cantor set. s study is achieved through the analysis the dynamics of the Veech group of this surface combined a modified version of Rauzy induction in the context of affine interval exchange transformations

Parabolic degrees and Lyapunov exponents for hypergeometric local systems

Consider the flat bundle on $\mathrm{CP}^1 - \{0,1,\infty \}$ corresponding to solutions of the hypergeometric differential equation $\prod_{i=1}^h (\mathrm D - \alpha_i) - z \prod_{j=1}^h (\mathrm D - \beta_j) = 0$ where $\mathrm D = z \frac {d}{dz}$. For $\alpha_i$ and $\beta_j$ distinct real numbers, this bundle is known to underlie a complex polarized variation of Hodge structure. Setting the complete hyperbolic metric on $\mathrm{CP}^1 - \{0,1,\infty \}$, we associate $n$ Lyapunov exponents to this bundle. We compute the parabolic degrees of the holomorphic subbundles induced by the variation of Hodge structure and study the dependence of the Lyapunov exponents in terms of these degrees by means of numerical simulations

Organisation syllabique : quelles évidences phonétiques ?

International audienceIn this study, we examine consonants sequences inTashlhiyt Berber in order to demonstrate that theirsyllabic organization can surface in their phoneticproperties. Two types of three consonants sequencesvarying according to the degree of sonority of C1 areconsidered. Following syllabification principles of thelanguage, these two types are considered to differ intheir syllabic structure. Observation of thelinguopalatal articulatory properties of the consonantsand of the temporal coordination pattern between theseconsonants do show differences between the two typesof sequences. These phonetic differences areinterpreted as reflecting different syllabic structures,and results are confronted to the syllabification of thestring proposed on phonological grounds.Cet article examine l'organisation syllabique de certaines séquences consonantiques et questionne sa possible manifestation phonétique

On the phonetic implementation of syllabic consonants and vowel-less syllables in Tashlhiyt

This paper presents an acoustic and electropalatographic study of how vowel-less syllables and their constituents are phonetically implemented in Tashlhiyt Berber. Three issues are addressed. First, we determine whether the acoustic and articulatory make-up of a consonant changes as a function of its position within a syllable (C-nucleus vs. C-onset vs. C-coda). Second, we consider the patterns of articulatory coordination between consonants as a function of their position within and across the syllable. Third, we test whether nuclei consonants are produced as sequences of schwa vowels + consonants. While some differences are observed in linguopalatal articulation, position in a syllable is not found to affect the acoustic and articulatory duration of a consonant in Tashlhiyt. Interestingly, syllable organization appears to be reflected in the specifications of the coordination between consonants. Consonants in nucleus position are more stable in their coordination with flanking consonants and are less overlapped by a following consonant. In addition, our results suggest that the occurrence of a schwa-like element before a consonant depends on the laryngeal specifications of the consonants in the sequence rather than on its syllabic status.This paper presents an acoustic and electropalatographic study of how vowel-less syllables and their constituents are phonetically implemented in Tashlhiyt Berber. Three issues are addressed. First, we determine whether the acoustic and articulatory make-up of a consonant changes as a function of its position within a syllable (C-nucleus vs. C-onset vs. C-coda). Second, we consider the patterns of articulatory coordination between consonants as a function of their position within and across the syllable. Third, we test whether nuclei consonants are produced as sequences of schwa vowels + consonants. While some differences are observed in linguopalatal articulation, position in a syllable is not found to affect the acoustic and articulatory duration of a consonant in Tashlhiyt. Interestingly, syllable organization appears to be reflected in the specifications of the coordination between consonants. Consonants in nucleus position are more stable in their coordination with flanking consonants and are less overlapped by a following consonant. In addition, our results suggest that the occurrence of a schwa-like element before a consonant depends on the laryngeal specifications of the consonants in the sequence rather than on its syllabic status.Este artículo presenta un estudio acústico y electropalatográfico sobre cómo se implemententan en Bereber Tashlhyt las sílabas sin vocales y sus constituyentes. Para ello se abordan tres cuestiones. En primer lugar determinamos si la composición acústica y articulatoria de una consonante cambia como una función de su posición en la sílaba (C-núcleo vs. C-ataqu, vs. C-coda). En segundo lugar, consideramos los patrones de la coordinación articulatoria entre consonantes como una función de su posición en y a través de la sílaba. Y en tercer lugar, examinamos si los núcleos de las sílabas son producidos como secuencia de vocal schwa + consonantes. Si bien se han observado algunas diferencias en la articulación linguopalatal, por otra parte no se ha encontrado que la posición en una sílaba afecte a la duración articulatoria y acústica de las consonantes en Tashlhyt. Curiosamente, la organización de la sílaba parece estar reflejada en las especificaciones de la coordinación entre consonantes. Las consonantes en la posición de núcleo son más estables en su coordinación con las consonantes de sus flancos y están menos solapadas por la consonante siguiente. En adición, nuestros resultados sugieren que la aparición de elementos tipo schwa antes de una consonante depende de las especificaciones laríngeas de las consonantes en la secuencia más que de su estatus silábico

Simplicity of spectra for certain multidimensional continued fraction algorithms

In the current paper we prove simplicity for the spectrum of Lyapunov exponents for triangle sequence and Selmer algorithm in dimension 3. We introduce a strategy that can be applied for a wide class of Markovian MCF

Collapse/subsidence : role and influence of overburden in Lorraine iron mines case

International audienceThis paper presents several large-scale numerical modellings of valley and tray situations with the presence or not of vertical fractures. Through these modellings, we firstly attempt to evaluate an influence zone, in terms of stress variations induced by the creation of the valley. Next we study more particularly the behaviour of a stiff overburden, according to situations, with the aim to estimate if a valley and/or the presence of subvertical fractures influence the overburden massivity.Ce papier présente plusieurs modélisations à grande échelle d'une situation de vallée et de plateau en présence ou non d'une fracturation verticale. A travers ces modélisations, nous tentons d'évaluer une zone d'influence, en termes de variations de contraintes induites par la création de la vallée. Puis nous étudions plus particulièrement le comportement d'une couverture raide, en fonction des situations, dans l'objectif d'estimer si une vallée et/ou une fracturation subverticale influencent la massivité du recouvremen

62 vs. 96 electrodes: a comparative analysis of Reading and Kay Elemetrics EPG pseudo-palates

International audienceThe pseudo-palates used with the Kay Elemetrics and Reading EPG systems mainly differ according to their number of electrodes, 96 vs. 62 respectively, and the spatial repartition of the electrodes over the palate. The two pseudo-palates also greatly differ in their price according to their number of electrodes. This study compares how variations in linguopalatal contact are reflected by the two pseudo-palates and evaluates the contribution of the extra 34 electrodes of the Kay system in terms of description of segments articulation, discrimination between articulatory patterns, and replication of attested coarticulatory effects. Results show that the Kay system reflects with greater precision the actual contact of the tongue against the palate and subtle articulatory variations. It provides additional information mostly in the palatal, velar and dental regions. However, with 62 electrodes, the Reading pseudo-palate is still able to reflect the articulatory variations studied and to discriminate articulatory patterns. Implications of these results for improving the resolution of the Reading pseudo-palate are discussed

62 vs. 96 electrodes: a comparative analysis of Reading and Kay Elemetrics EPG pseudo-palates

International audienceThe pseudo-palates used with the Kay Elemetrics and Reading EPG systems mainly differ according to their number of electrodes, 96 vs. 62 respectively, and the spatial repartition of the electrodes over the palate. The two pseudo-palates also greatly differ in their price according to their number of electrodes. This study compares how variations in linguopalatal contact are reflected by the two pseudo-palates and evaluates the contribution of the extra 34 electrodes of the Kay system in terms of description of segments articulation, discrimination between articulatory patterns, and replication of attested coarticulatory effects. Results show that the Kay system reflects with greater precision the actual contact of the tongue against the palate and subtle articulatory variations. It provides additional information mostly in the palatal, velar and dental regions. However, with 62 electrodes, the Reading pseudo-palate is still able to reflect the articulatory variations studied and to discriminate articulatory patterns. Implications of these results for improving the resolution of the Reading pseudo-palate are discussed