Publications scientifiques de l'Université de Reims Champagne-Ardenne
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Les collections et les moucherons du genre Culicoides (Diptera : Ceratopogonidae)
No full textNational audienceLes moucherons du genre Culicoides sont de petits diptères piqueurs de 1 à 4 mm. Seules les femelles sont hématophages et certaines espèces sont très agressives. Les culicoïdes sont responsables de la transmission de nombreux agents pathogènes aux Mammifères, y compris les humains mais aussi les animaux domestiques et sauvages, et Oiseaux. Actuellement près de 1400 espèces sont décrites à travers le Monde. La classification des espèces est presque entièrement phénétique (basé sur la similarité globale). Le développement de la biologie moléculaire notamment le « barcoding » du Cytochrome Oxidase I (COI) ne permet pas de résoudre toutes les questions de classification des culicoïdes. Ceci est d’autant plus vrai quand des espèces décrites ne sont pas retrouvées dans les collectes récentes. Un des moyens est le recours aux spécimens de collections, en utilisant notamment la morphométrie géométrie. Nous présentons ici au travers de quelques exemples, comment l’utilisation des collections peut aider les taxonomistes dans l’identification des espèces
Projective functions
No full textWe study projective functions. We prove that projective functions generalise lower and upper-semianalytic ones while being stable by composition and difference. We show that the class of projective functions is closed under sums, differences, products, finite suprema and infima, sections and compositions. Assuming the set-theoretical axiom of Projective Determinacy, we also prove measurable selection results, stability under integration, and the existence of epsilon-optimal selectors. Finally, we illustrate how these results are important in the context of model uncertainty
Implementation of artificial intelligence for the diagnosis of intrahepatic ductular lesions
No full textInternational audienc
A selective genetic algorithm - PLS-DA approach based on untargeted LC-HRMS: Application to complex biomass samples
No full textInternational audienceSupervised multivariate analyses (MVA) are commonly used to extract valuable information, classify samples and highlight data trends from complex LC-HRMS datasets. However, traditional MVA methods, such as partial least-squares discriminant analysis (PLS-DA), may not provide sufficient class discrimination in the case of complex mixtures due to the presence of confounders, high-dimensionality and multicollinearity. In this regard, variable selection methods such as genetic algorithms can reduce datasets by retaining explanatory information while discarding non-informative features. The hyphenation of these selective heuristic methods and highly interpretable PLS-DA has shown significant potential for sample discrimination in spectroscopic techniques but has never been applied to complex LC-HRMS data.Therefore, this work investigated the potential of combining variable selection by GA and classification by PLS-DA for identifying key chemical descriptors in these intricate LC-HRMS datasets. The determination of low reactivity discriminants (i.e., potential enzymatic inhibitors) in complex biomass samples was chosen as a case study and is presented in this work. Initially, PLS-DA was applied to an LC-ESI(±)-HRMS dataset containing 2167 features. However, the resulting model suffered from overfitting and yielded sub-optimal classification for low reactivity samples. Subsequently, GA was employed in triplicate, resulting in 768 final models. The most predictive model retained only 418 variables (i.e., an 81 % decrease in the dataset) and was subjected to PLS-DA. The new supervised model avoided overfitting and demonstrated significantly improved classification for low reactivity samples, achieving sensitivity, precision, and accuracy increases of 45 %, 25 %, and 38 %, respectively. Ultimately, an original strategy based on combining the variables’ importance in projection (VIP), GA-selection frequency (GA-SF) and cosine similarity was used to pinpoint species associated with low enzymatic reactivity. This study marks the first application of GA-PLS-DA for LC-HRMS data analysis. This approach effectively streamlined feature selection and enhanced class discrimination, successfully identifying 10 potential inhibitory features within the biomass samples. This methodology offers significant potential for studies on complex mixtures that encounter limited classification and/or overfitting issues with traditional supervised MVA methods
Chemical Constituents from Ethyl Acetate Extract of <i>Graptophyllum</i> <i>glandulosum</i> Turrill and New Semi-Synthetic Derivative with Antimicrobial Activities
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RNA-Seq Reveals Differential Responses in Vitis vinifera Cultivars Protected by Distinct Biocontrol Agents Against Neofusicoccum parvum Bt67
No full textInternational audienceBotryosphaeria dieback (BD) is a worldwide grapevine trunk disease constituting a serious threat for sustainable grapevine production, especially in the context of climate change. Effective treatments to control BD are still lacking, prompting the exploration of new non-chemical alternatives. Among these, BioControl Agents (BCAs), such as Trichoderma spp. and Bacillus spp., described as promising. This study aims to thoroughly investigate the physiological changes in grapevines induced by two BCAs, Bacillus subtilis (Bs PTA-271) and Trichoderma atroviride (Ta SC1), which are used to protect two cultivars from Neofusicoccum parvum Bt67 (Np-Bt67) infection. Using non-target transcriptomic analysis (RNA-seq) and validation by qRT-PCR, this research offers novel insights into the molecular responses associated to Np-Bt67 infection in Chardonnay and Tempranillo cultivars, in relationship with the protective mechanisms conferred by each BCA. RNA-seq reveals that cultivars show no common transcriptional changes upon pathogen challenge. In Chardonnay, changes are mainly related to terpene/carotenoid pathways, while in Tempranillo, they mostly relate to amino acid transport and photosynthesis. Following the inoculation of protective BCA, changes are also distinct between infected cultivars: Bs PTA-271 protecting effect against infected Chardonnay is mainly related to the phenylpropanoid pathway and secondary metabolic processes, whereas that of Ta SC1 for Tempranillo correlates with much more metabolic changes. Consecutive validation by qRT-PCR provides markers indicating grapevine susceptibility vs. protection against Np-Bt67, some of which are shared by both cultivars. These markers could offer valuable tools for monitoring the health status of grapevine towards N. parvum
Enhancing Work Health and Motivation in the Medico-Social Sector through Self-Determination Training
No full textInternational audienceThe objective of the French program "Un chez soi d'abord (UCSD)" is to support vulnerable populations (homeless) with severe mental health disorders through housing. Inspired by North American "Housing First" models, this initiative is distinguished by its grounding in the principles of mental health recovery (Deegan, 1997) and the principles of Self-Determination Theory (SDT; Ryan & Deci, 2017). Thus, the UCSD program diverges from the traditional social support model, whose practices may be perceived as frustrating psychological needs as defined by SDT. While the professionals within UCSD program (e.g., nurses, social workers) are trained in recovery principles, they are not trained in the principles of SDT, nor are they supported in integrating these principles into their practices and professional identities. Based on a quasiexperimental longitudinal study, this research aims to evaluate the effectiveness of in-depth training in SDT.Three groups of participants were created: the first group consisted of UCSD professionals who received in-depth SDT training; the second group included UCSD employees who did not receive the training; and the third group comprised professionals working outside the UCSD program in similar organizations (i.e., housing support for homeless). The different groups responded to a series of measures at two time points (T1 before the training, T2 three months after T1) on variables related to occupational health (i.e., job satisfaction, meaning of work, burnout, and work engagement) as well as on identification, work motivation, and psychological needs states
Trajectoires identitaires de langues minoritaires: entre reconnaissance et marginalisation
No full textInternational audienceLa langue joue un rôle fondamental dans la construction identitaire, en particulier dans lescommunautés où elle sert à revendiquer une appartenance sociale, régionale ou nationale(Blanchet, 2022 ; Launey, 2022). Dans les contextes de langues minoritaires, comme celui dela frontière franco-italienne, les locuteurs du royasque et d’autres variétés liguriennes évoluent entre l’assimilation aux normes dominantes et l’affirmation d’une identité locale distincte (Heller, 2007). Bien que souvent marginalisées, ces langues régionales conservent une forte charge symbolique en tant que marqueurs d’identité locale, mais leur usage est en déclin sous la pression des langues dominantes telles que le français et l'italien (Bourdieu, 1982 ; Adret, 2009). Or, cette dynamique soulève des questions concernant la place de ces langues dans l’identité des locuteurs, particulièrement dans un contexte de transition sociolinguistique où leur pratique devient de plus en plus rare (García, 2009). De plus, les politiques linguistiques et éducatives jouent un rôle central dans la redéfinition des rapports entre langue, identité et pouvoir, en influençant la visibilité et la reconnaissance des langues minoritaires dans les sphères publiques et éducatives (Hélot, Barni, Jannsens, & Bagna, 2012 ; Fishman, 1991). Aussi, bien que des dispositifs éducatifs existent pour intégrer des langues minoritaires comme le royasque, ces initiatives demeurent marginales et peinent à inverser leur déclin (Maurais & Morris, 2003). Cette étude s’appuie sur une méthodologie qualitative combinant des entretiens semi-directifs, des observations ethnographiques et une analyse de discours. Le terrain de l’étude inclut plusieurs communes de la région frontalière franco-italienne, où le royasque et d’autres variétés liguriennes sont encore parlées, bien que par une population vieillissante. En revanche, les jeunes générations privilégient principalement le français ou l'italien. Les participants ont été sélectionnés parmi des locuteurs de différentes tranches d’âge, y compris des enseignants et des membres de la communauté locale, afin de mieux saisir les enjeux intergénérationnels.Les résultats montrent une opposition marquée entre les jeunes, qui considèrent le royasque comme une langue « du passé », et les générations plus âgées, pour qui cette langue demeure un symbole de résistance culturelle et un élément fondamental de leur identité (Barth, 1969).En effet, les jeunes, souvent confrontés à des normes sociales et professionnelles favorisant le français ou l'italien, sont moins enclins à utiliser le royasque dans leurs interactionsquotidiennes, bien que cette langue soit valorisée dans des contextes familiaux ou festifs (Hélot & Cavalli, 2017). À l’inverse, les adultes plus âgés continuent à pratiquer le royasque dans un cadre informel, pour maintenir un lien avec leur héritage culturel et leur communauté d’origine.Enfin, l’analyse des politiques linguistiques locales révèle que, bien que des initiatives existent pour valoriser le royasque dans l’éducation et la culture, elles restent insuffisantes face à la pression des langues majoritaires. Les dispositifs éducatifs intégrant le royasque sont souvent perçus comme marginaux et peinent à renverser la tendance au déclin. Toutefois, les résultats suggèrent que la mise en place d’une politique linguistique plus affirmée et le renforcement des dispositifs éducatifs en faveur du plurilinguisme (Creese & Blackledge, 2010) pourraient inverser cette dynamique, en offrant aux jeunes générations un cadre valorisant leur identité plurilingue (May, 2011 ; De Mejía, 2002)
Towards Sustainable Knowledge Management: The Emergence of Non-Pre-Competitive Knowledge Ecosystems in a Regulated Safety Context
No full textInternational audienceThis study presents a qualitative case study exploring how inter-organizational knowledge management is structured within a regulated safety context, where the core objective is the long-term preservation of critical knowledge. Within such a context, organizations collaborate to collectively create, share, and sustain knowledge over time. Our analysis shows that the most effective response to this challenge lies in the reconfiguration of inter-organizational architecture into a non-pre-competitive knowledge ecosystem. This type of ecosystem, still underexplored in the literature, is characterized by the absence of commercial or anticipatory competitive goals. It is structured around the production, preservation, and emergence of interconnected knowledge systems, supported by organizational innovation involving new practices, structures, and coordination mechanisms.Adopting an organizational perspective that bridges insights from knowledge management and organizational innovation, we analyze the emergence of such an ecosystem through the case of Kronos, a network of organizations operating in a highly regulated environment. The case highlights how relationship formalization, institutional regulation, and the presence of a focal actor contribute to a collective goal of knowledge transmission, sustainability, and systematization. This paper offers a conceptualization of non-pre-competitive knowledge ecosystems, emphasizing their distinctiveness from traditional pre-competitive frameworks and underlining the structuring role of organizational innovation in sustainable knowledge management