The perception of phonemic contrasts in a non-native dialect

This study examined the impact on speech processing of regional phonetic/phonological variation in the listener's native language. The perception of the /e/-/epsilon/ and /o/-/upside down c/ contrasts, produced by standard but not southern French native speakers, was investigated in these two populations. A repetition priming experiment showed that the latter but not the former perceived words such as /epe/ and /epepsilon/ as homophones. In contrast, both groups perceived the two words of /o/-/upside down c/ minimal pairs (/pom/-/p(uspide down c)m/) as being distinct. Thus, standard-French words can be perceived differently depending on the listener's regional accent.     

Exponential decay for sc-gradient flow lines

In this paper we introduce the notion of sc-action functionals and their sc-gradient flow lines. Our approach is inspired by Floer’s unregularized gradient flow. The main result of this paper is that under a Morse condition, sc-gradient flow lines have uniform exponential decay towards critical points. The ultimate goal for the future is to construct an M-polyfold bundle over an M-polyfold such that the space of broken sc-gradient flow lines is the zero set of an appropriate sc-section. Here uniform exponential decay is essential. Of independent interest is that we derive exponential decay estimates using interpolation inequalities as opposed to Sobolev inequalities. An advantage is that interpolation inequalities are independent of the dimension of the source space.     

Global Surfaces of Section in the Planar Restricted 3-Body Problem

The restricted planar three-body problem has a rich history, yet many unanswered questions still remain. In the present paper we prove the existence of a global surface of section near the smaller body in a new range of energies and mass ratios for which the Hill’s region still has three connected components. The approach relies on recent global methods in symplectic geometry and contrasts sharply with the perturbative methods used until now.     

The role of continuous and discrete water structures in protein function

Proteins have evolved to perform numerous roles as specific catalysts and nano-machines. Some of the mechanisms exploited by evolution are clear. Hydrophobicity drives the stabilization energy of folding, charges mediate long-range interactions and facilitate catalysis, and specific geometries and hydrogen bonding patterns facilitate molecular recognition and catalysis. In this work, we examine the energy landscape of protein dynamics in terms of the continuous and discrete water structures that control protein dynamics. We observe that the internal structures at the active site of proteins are constantly shaped by strong interactions with hydration shell and bulk water motions. By describing the energy landscape of proteins in terms of its three component motions; conformational, hydration and protonation, and electronic structure, it is possible to systematically understand protein function.     

Filtered Hopf algebras and counting geodesic chords

We prove lower bounds on the growth of certain filtered Hopf algebras by means of a Poincaré–Birkhoff–Witt type theorem for ordered products of primitive elements. When applied to the loop space homology algebra endowed with a natural length-filtration, these bounds lead to lower bounds for the number of geodesic paths between two points. Specifically, given a closed manifold  \(M\) whose universal covering space is not homotopy equivalent to a finite complex and whose fundamental group has polynomial growth, for any Riemannian metric on  \(M\) , any pair of non-conjugate points \(p,q \in M\) , and every component  \({\mathcal C}\) of the space of paths from  \(p\) to  \(q\) , the number of geodesics in  \({\mathcal C}\) of length at most  \(T\) grows at least like \(e^{\sqrt{T}}\) . Using Floer homology, we extend this lower bound to Reeb chords on the spherisation of  \(M\) , and give a lower bound for the volume growth of the Reeb flow.     

Existence of either a periodic collisional orbit or infinitely many consecutive collision orbits in the planar circular restricted three-body problem

Mathematische Zeitschrift - In the restricted three-body problem, consecutive collision orbits are those orbits which start and end at collisions with one of the primaries. Interests for such...     

What affects the presence versus absence of schwa and its duration: a corpus analysis of French connected speech

This study presents an analysis of over 4000 tokens of words produced as variants with and without schwa in a French corpus of radio-broadcasted speech. In order to determine which of the many variables mentioned in the literature influence variant choice, 17 predictors were tested in the same analysis. Only five of these variables appeared to condition variant choice. The question of the processing stage, or locus, of this alternation process is also addressed in a comparison of the variables that predict variant choice with the variables that predict the acoustic duration of schwa in variants with schwa. Only two variables predicting variant choice also predict schwa duration. The limited overlap between the predictors for variant choice and for schwa duration, combined with the nature of these variables, suggest that the variants without schwa do not result from a phonetic process of reduction; that is, they are not the endpoint of gradient schwa shortening. Rather, these variants are generated early in the production process, either during phonological encoding or word-form retrieval. These results, based on naturally produced speech, provide a useful complement to on-line production experiments using artificial speech tasks.     

Periodic orbits in the restricted three-body problem and Arnold’s <Emphasis Type="Italic">J</Emphasis><Superscript>+</Superscript>-invariant

We apply Arnold’s theory of generic smooth plane curves to Stark–Zeeman systems. This is a class of Hamiltonian dynamical systems that describes the dynamics of an electron in an external electric and magnetic field, and includes many systems from celestial mechanics. Based on Arnold’s J ⁺-invariant, we introduce invariants of periodic orbits in planar Stark–Zeeman systems and study their behavior.     

Floer homology for magnetic fields with at most linear growth on the universal cover

The Floer homology of a cotangent bundle is isomorphic to loop space homology of the underlying manifold, as proved by Abbondandolo and Schwarz, Salamon and Weber, and Viterbo. In this paper we show that in the presence of a Dirac magnetic monopole which admits a primitive with at most linear growth on the universal cover, the Floer homology in atoroidal free homotopy classes is again isomorphic to loop space homology. As a consequence we prove that for any atoroidal free homotopy class and any sufficiently small $\tau >0$, any magnetic flow associated to the Dirac magnetic monopole has a closed orbit of period τ belonging to the given free homotopy class. In the case where the Dirac magnetic monopole admits a bounded primitive on the universal cover we also prove the Conley conjecture for Hamiltonians that are quadratic at infinity, i.e., we show that such Hamiltonians have infinitely many periodic orbits.