Teeth and dentitions contain many morphological characters which give them a particularly important weight in comparative anatomy, systematics, physiology and ecology. As teeth are organs that contain the hardest mineralized tissues vertebrates can produce, their fossil remains are abundant and the study of their anatomy in fossil specimens is of major importance in evolutionary biology. Comparative anatomy has long favored studies of dental characters rather than features associated with tooth attachment and implantation. Here we review a large part of the historical and modern work on the attachment, implantation and replacement of teeth in Amniota. We propose synthetic definitions or redefinitions of most commonly used terms, some of which have led to confusion and conflation of terminology. In particular, there has long been much conflation between dental implantation that strictly concerns the geometrical aspects of the tooth-bone interface, and the nature of the dental attachment, which mostly concerns the histological features occurring at this interface. A second aim of this work was to evaluate the diversity of tooth attachment, implantation and replacement in extant and extinct amniotes in order to derive hypothetical evolutionary trends in these different dental traits over time. Continuous dental replacement prevails within amniotes, replacement being drastically modified only in Mammalia and when dental implantation is acrodont. By comparison, dental implantation frequently and rapidly changes at various taxonomic scales and is often homoplastic. This contrasts with the conservatism in the identity of the tooth attachment tissues (cementum, periodontal ligament, and alveolar bone), which were already present in the earliest known amniotes. Because the study of dental attachment requires invasive histological investigations, this trait is least documented and therefore its evolutionary history is currently poorly understood. Finally, it is essential to go on collecting data from all groups of amniotes in order to better understand and consequently better define dental characters.

BackgroundThe dentitions of extinct organisms can provide pivotal information regarding their phylogenetic position, as well as paleobiology, diet, development, and growth. Extant birds are edentulous (toothless), but their closest relatives among stem birds, the Cretaceous Hesperornithiformes and Ichthyornithiformes, retained teeth. Despite their significant phylogenetic position immediately outside the avian crown group, the dentitions of these taxa have never been studied in detail. To obtain new insight into the biology of these ‘last’ toothed birds, we use cutting-edge visualisation techniques to describe their dentitions at unprecedented levels of detail, in particular propagation phase contrast x-ray synchrotron microtomography at high-resolution.ResultsAmong other characteristics of tooth shape, growth, attachment, implantation, replacement, and dental tissue microstructures, revealed by these analyses, we find that tooth morphology and ornamentation differ greatly between the Hesperornithiformes and Ichthyornithiformes. We also highlight the first Old World, and youngest record of the major Mesozoic clade Ichthyornithiformes. Both taxa exhibit extremely thin and simple enamel. The extension rate of Hesperornis tooth dentine appears relatively high compared to non-avian dinosaurs. Root attachment is found for the first time to be fully thecodont via gomphosis in both taxa, but in Hesperornis secondary evolution led to teeth implantation in a groove, at least locally without a periodontal ligament. Dental replacement is shown to be lingual via a resorption pit in the root, in both taxa.ConclusionsOur results allow comparison with other archosaurs and also mammals, with implications regarding dental character evolution across amniotes. Some dental features of the ‘last’ toothed birds can be interpreted as functional adaptations related to diet and mode of predation, while others appear to be products of their peculiar phylogenetic heritage. The autapomorphic Hesperornis groove might have favoured firmer root attachment. These observations highlight complexity in the evolutionary history of tooth reduction in the avian lineage and also clarify alleged avian dental characteristics in the frame of a long-standing debate on bird origins. Finally, new hypotheses emerge that will possibly be tested by further analyses of avian teeth, for instance regarding dental replacement rates, or simplification and thinning of enamel throughout the course of early avian evolution.Electronic supplementary materialThe online version of this article (doi:10.1186/s12862-016-0753-6) contains supplementary material, which is available to authorized users.

Cette étude prolonge un travail de recherche sur la signification des noms des parties du corps humain (Npc) (Bertin, 2018). On s'intéresse à la construction illustrée par Colin a le front de venir à cette réunion (NPV). Après un inventaire des Npc compatibles avec NPV, on procède à une analyse sémantique : d'une part, on cerne le sens de NPV (en se focalisant sur la contribution du Npc) et, d'autre part, on tire profit de cette première étape pour l'analyse sémantique des Npc eux-mêmes.

Cette étude porte sur une série de périphrases verbales (PV) de la forme «  avoir le N pc de V inf  », où N pc désigne un « nom de partie du corps humain ». Après une recension des N pc compatibles avec cette construction, nous observons qu’elle peut effectivement être considérée comme une PV et que l’emploi du N pc  – envisagé comme un emploi « qualité » – permet l’expression d’un concept modal. Nous précisons alors le concept modal associé à l’emploi de chaque N pc dans «  avoir le N pc de V inf  » selon l’approche des modalités de Gosselin (2010).

<p>Organic aerosol (OA) from natural or anthropogenic origin can be directly emitted into the atmosphere (primary organic aerosols, POA) or formed by secondary processes via the oxidation of volatile organic compounds (VOC). However, the formation pathways and their chemical composition of these secondary organic aerosols (SOA), which may contribute up to 90% of the OA mass, are not well understood to date, which is problematic due to the relevance of SOA on climate. To address this issue, this study uses a tracer-based approach to identify and quantify the contribution of different anthropogenic/biogenic VOCs precursors to the SOA formation. To do so, we combine experiments in a large scale atmospheric simulations chamber, CESAM (which means Multiphase Atmospheric Experimental Simulation Chamber), and field measurements during the ACROSS (Atmospheric ChemistRy Of the Suburban foreSt) campaign conducted in the Paris area in summer 2022. This approach provides both a mechanistic study of the oxidation of targeted VOCs in simulated and controlled rural/urban atmospheres and the identification of targeted tracers in the real atmosphere, to quantify their concentrations in ambient air.</p> <p>The ACROSS dataset consists in atmospheric samples of submicron aerosols collected twice a day (day and night) in the urban area of Paris and the Rambouillet forest on the south-west of Paris, as well as samples collected onboard the Safire ATR-42 research aircraft on low-level flights targeting the  evolution and dilution of the Paris urban plume. The CESAM chamber dataset consists in samples of SOA generated by the OH oxidation of toluene/ m-xylene in various conditions.</p> <p>Filters are analyzed to provide with the chemical composition at the molecular scale by SFE-GC-MS (Supercritical Fluid Extraction Gas Chromatography- Mass Spectrometry) and UPLC-QTOF-MS (Ultra Performance Liquid Chromatography Time of Flight Mass Spectrometry). The organic mass and chemical speciation are obtained by aerosol mass spectrometry and the organic carbon (OC) concentrations by thermal-optical analysis.</p> <p>The first results of the ambient samples of Paris revealed that the OC concentration varied between 0.69 ± 0.07 and 9.48 ± 0.51 µgC/m<sup>3</sup>, which correspond to the 28% and 53% of the total mass of the submicron aerosols, for background and polluted (fire) conditions, respectively. These diverse conditions are favorable to trace the compounds identified during the simulation chamber experiments, such as benzoic acid, succinic acid, and 2-methyl-4-nitrophenol. These attempts will be presented and discussed in order to determine the contribution of specific precursors to SOA formation.</p>

This study deals with meaning construction in idiomatic phrases (locutions figées/figements). We focus on three French idioms involving the word cœur (à contrecœur, de bon cœur, de tout cœur). To begin, we give a brief account of idiomaticity’s typical criteria, insisting on the common idea that idioms are semantically opaque (non-compositional): their meanings are not a combination of literal meanings (Gross 1996). We argue that another point of view is productive. Indeed, using the notion of “holistic compositionality” (Gosselin 2013), we investigate the way meaning may arise from the combination of words’ abstract semantic contributions (compositionality principle) and take shape contextually (contextuality principle). The primary goal of the study is to analyze the meaning of à contrecœur, de bon cœur, de tout cœur using this approach – which happens to be more accurate than the literal meaning combination approach. To achieve this goal for each of these three idioms: (1) we examine a sample of 200 utterances (and the contexts in which they occur) coming from a large data-source (frWaC) and (2) we take advantage of previous semantic descriptions of cœur (Bertin 2018, 2019), contre (Amiot & De Mulder 2003; Paillard 2003), bon (Katz 1964) and tout (Bat-Zeev Shyldkrot 1995). These two methodological tools shed light on the operation of the semantic mechanism and emphasize the relevance of the “holistic compositionality” approach when applied to idioms’ meaning construction.

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This study draws on lexical semantics to support a discourse analysis perspective (Gosselin 2018; Galatanu 2018). It examines the use of the French noun artère ‘artery’ (a common word from the lexicon (Maingueneau 2021)) to refer to a street-like entity (street, avenue, boulevard, etc.). The empirical investigation was based on an analysis of 150 utterances (extracted from three full-text databases). On the one hand, the study shows that selecting artère to refer to a street-like entity is a discursive strategy targeting a significant representation of the referent, especially when this referent is not a prototypical urban street. On the other hand, it supports the idea that this discursive choice strongly relies on the lexical signification of artère (Bertin 2018).