Does the invasive plant Elymus athericus modify fish diet in tidal salt marshes?

The invasion of Mont-Saint-Michel Bay salt marshes (France) by a grass species (Elymus athericus) has led to important changes in vegetation cover, which is likely to modify the habitat for many invertebrates. Some of them constitute the main food items for several fish species, such as young sea bass (Dicentrarchus labrax) and sand goby (Pomatoschistus minutus), that feed in salt marsh creeks during high tides. As a result, fish nursery functions of salt marshes could be modified by the E. athericus invasion. In order to test this hypothesis, gut contents of the two most abundant fish species (sea bass and sand goby) were compared before and after E. athericus invasion in the same salt marsh creek and using the same methodology. The accessibility and availability of the main food item, the semi-terrestrial amphipod Orchestia gammarella, were estimated and compared between invaded (dominated by E. athericus) and original areas (dominated by Atriplex portulacoides). Gut content analysis showed a significantly greater percentage of fish leaving with empty guts from E. athericus areas than from A. portulacoides areas. The sea bass diet composition study showed a major shift in the relative importance of the main food items: before E. athericus invasion, diets were dominated by the semi-terrestrial species O. gammarella, whereas after the E. athericus invasion they were dominated by a marine mysid Neomysis integer. The same trend was found for sand gobies, with a shift of the main food item from O. gammarella before invasion to the polychaete Hediste diversicolor after invasion. These trophic changes may be explained by the lower accessibility and availability of O. gammarella in invaded communities than in natural ones. The E. athericus invasion, observed throughout northern Europe, is thus likely to disturb trophic function of natural salt marshes for fish. This preliminary study of the E. athericus invasion is also an illustration that invasive species are an urgent problem in conservation biology

A new vertical nanoporous functional structure process fabrication to control one dimensional nanostructure growth

International audienceA novel vertical nanoporous structure is reported as a starting point for the fabrication of a fully-surround gate field effect transistor (FET) based on well-ordered nanostructures array. The proposed porous stacking is perfectly suited both for the collective organization of high density (up to 1011.cm-2) arrays of nanostructures like nanowires (NWs) or nanotubes (NTs), as with calibrated diameters (during growth), as well as for easing the Source, Gate, and Drain electrodes connections for individual or groups of nanostructures. Moreover the unique fully-surround gate architecture enables a quasi-ideal coupling between the gate and the channel, theoretically leading to improved devices performance and reduced global power consumption. In this paper we describe the main steps for this versatile and lithography-free technique to fabricate a multi-layer porous template down to the nanometer scale, as well as the first nanostructures (carbon NTs) growth attempts inside such functional template. We highlight the fact that the proposed porous structure may acts as a passive template for the one-dimensional nanomaterials growth as well as an active element in the future device. The proposed approach is in line with bottom-up fabrication approach to provide smaller devices, and is fully-compatible with classical processes used in the silicon industry

Laterally organized carbon nanotube arrays based on hot-filament chemical vapor deposition

International audienceLateral porous anodic alumina (PAA) templates were used to organize carbon nanotubes (CNTs) grown by a hot-filament assisted chemical vapor deposition (HFCVD) process. For the CNT growth, we used a modified "home-made" HFCVD system with two independently powered filaments which are fitted respectively on the methane (CH4) gas line, which serves as a carbon precursor and on the hydrogen (H2) gas line, which acts as an etching agent for the parasitic amorphous carbon. Various activation powers of the hot filaments were used to directly or indirectly decompose the gas mixtures at relatively low substrate temperatures. A parametric study of the HFCVD process has been carried out for optimizing the confined CNTs growth inside the lateral PAA templates

Annotation de la temporalité en corpus : contribution à l'amélioration de la norme TimeML

National audienceThis paper reports a critical analysis of the TimeML standard, in the light of a temporal annotation that was conducted on spoken French. It shows that the norm suffers from weaknesses that must be corrected to fit the needs of NLP and corpus linguistics. These limitations concern mainly 1) the separation of different levels of linguistic annotation, 2) the delimitation in the text of the events, and 3) the absence of a bridging temporal relation in the norm.Cet article propose une analyse critique de la norme TimeML à la lumière de l'expérience d'annotation temporelle d'un corpus de français parlé. Il montre que certaines adaptations de la norme seraient conseillées pour répondre aux besoins du TAL et des sciences du langage. Sont étudiées ici les questions de séparation des niveaux d'annotation, de délimitation des éventualités dans le texte et de l'ajout d'une relation temporelle de type associative

ANCOR, premier corpus de français parlé d'envergure annoté en coréférence et distribué librement

National audienceCet article présente la réalisation d'ANCOR, qui constitue par son envergure (453 000 mots) le premier corpus francophone annoté en anaphores et coréférences permettant le développement d'approches centrées sur les données pour la résolution des anaphores et autres traitements de la coréférence. L'annotation a été réalisée sur trois corpus de parole conversationnelle (Accueil_UBS, OTG et ESLO) qui le destinent plus particulièrement au traitement du langage parlé. En l'absence d'équivalent pour le langage écrit, il est toutefois susceptible d'intéresser l'ensemble de la communauté TAL. Par ailleurs, le schéma d'annotation retenu est suffisamment riche pour permettre des études en linguistique de corpus. Le corpus sera diffusé librement à la mi-2013 sous licence Creative Commons BY-NC-SA. Cet article se concentre sur sa mise en œuvre et décrit brièvement quelques résultats obtenus sur la partie déjà annotée de la ressource

ANCOR_Centre, a Large Free Spoken French Coreference Corpus: description of the Resource and Reliability Measures

International audienceThis article presents ANCOR_Centre, a French coreference corpus, available under the Creative Commons Licence. With a size of around 500,000 words, the corpus is large enough to serve the needs of data-driven approaches in NLP and represents one of the largest coreference resources currently available. The corpus focuses exclusively on spoken language, it aims at representing a certain variety of spoken genders. ANCOR_Centre includes anaphora as well as coreference relations which involve nominal and pronominal mentions. The paper describes into details the annotation scheme and the reliability measures computed on the resource

Covering various Needs in Temporal Annotation: a Proposal of Extension of ISO TimeML that Preserves Upward Compatibility

International audienceThis paper reports a critical analysis of the ISO TimeML standard, in the light of several experiences of temporal annotation that were conducted on spoken French. It shows that the norm suffers from weaknesses that should be corrected to fit a larger variety of needs in NLP and in corpus linguistics. We present our proposition of some improvements of the norm before it will be revised by the ISO Committee in 2017. These modifications concern mainly (1) Enrichments of well identified features of the norm: temporal function of TIMEX time expressions, additional types for TLINK temporal relations; (2) Deeper modifications concerning the units or features annotated: clarification between time and tense for EVENT units, coherence of representation between temporal signals (the SIGNAL unit) and TIMEX modifiers (the MOD feature); (3) A recommendation to perform temporal annotation on top of a syntactic (rather than lexical) layer (temporal annotation on a treebank)