Résultats de recherche

The workshop provides a forum for the discussion of new research directions and applications in Artificial Life, Evolutionary Computation and in related fields, where different disciplines and research areas could effectively meet. It was first held in 2007 in Sampieri (Ragusa), as the incorporation of two separate workshops (WIVA and GSICE). 

Initiated in 1969 by Pullmann and Del Re, the congress is an annual meeting to promote collaboration and friendship between Latin-speaking theoretical chemists. In its early years, European researchers were the main contributors. Subsequently, the Latin American community has made a major contribution, with the emergence of teams whose international reputation now extends far beyond our own community.We are delighted to be holding this meeting at the University of Namur, 55 years after the first CHITEL was organised in Paris, France. We are sure that this 2024 edition will once again be an opportunity to take advantage of the good humour and dynamism of Latin to encourage, develop and strengthen scientific exchanges.We look forward to welcoming you at the University of Namur,The CHITEL 2024 Local Organising Committee. Website

EMBO Courses and Workshops are selected for their excellent scientific quality and timelines, provision of good networking activities for all participants and speaker gender diversity (at least 40% of speakers must be from the underrepresented gender). Organisers are encouraged to implement measures to make the meeting environmentally more sustainable.Upon registration - More info and registration on the EMBO website.

Le jeudi 30 mai, pour notre dernier Chill&Sciences de la saison, Candy Sonvaux et Alexis Coyette, chercheurs en mathématiques, vous invitent à la découverte des mathématiques où les mouvements des planètes et la propagation des virus s’entremêlent jusqu’à impacter notre société.Chill&Science : des rencontres enrichissantesAvec près de 20 ans d’expérience de cafés scientifiques, le Confluent des Savoirs a mis en place un nouveau concept de rencontres scientifiques. Les Chill&Sciences sont l’occasion unique pour le public de venir échanger et poser des questions aux experts sur des sujets de recherche en lien avec l’actualité et des thématiques citoyennes.Venez profiter de l’ambiance unique et décontractée du Quai22. Des chercheur·es et expert·es des sept facultés de l’Université de Namur présenteront leurs recherches et discuteront avec vous autour d’un verre (ou deux mais jamais sans exagération).En pratiqueLes rencontres s'adressent à toutes et tous dès l'âge de 16 ans. Les soirées sont limitées à une vingtaine de personnes afin de garantir une ambiance décontractée et pour faciliter les discussions. Les rencontres se déroulent si minimum 10 personnes sont inscrites.  Sauf exception, les rencontres se déroulent tous les 2 mois à l'espace culturel de l'Université de Namur, le Quai22, situé au n°22 Rue du Séminaire.Tarif La participation à un Chill&Sciences coûte 5€. Un pass annuel à tarif préférentiel est proposé. Attention : tarif préférentiel pour les étudiants (code de réduction : PromoCDS).Le tarif de réservation comprend une boisson* (soft ou bière), un snack (chips et biscuits) et les frais de gestion liés à l'organisation Sauf annulation de notre part, les réservations sont non remboursables. (* des boissons supplémentaires seront disponibles moyennant paiement électronique.) 

Title of the dissertation: Ion implantation in Low-E coatings Low-emissivity (Low-E) coating technology revolutionizes glass applications for windows, offering high optical transparency while reducing heat transfer. They consist of a silver-based thin film deposed on a glass panel by physical vapor deposition. However, these coatings are fragile and must be placed inside a double-glazing cavity where an inert gas resides. Otherwise, they can be easily degraded by bad atmospheric conditions.The thesis approach is to combine low-E technology with a post-treatment of ion implantation. The research question driving this thesis is: how does ion implantation enhance the durability of low-E coatings containing silver?The experiments conducted during the thesis show that implantation indeed increases the coating resistance while having a small impact on its color. However, the treatment degrades the thermal insulation properties. Hence, a series of hypotheses are formulated based on the literature to explain and control this behavior.A deeper investigation shows that implantation impacts the silver nanostructure. First by dewetting the film which allows reorganization into larger crystallites, second by forcing silver mixing at its interface through ballistic ejections. These two phenomena increase the toughness of the silver interface by interlocking effects. However, dewetting has also been linked to thermal insulation properties degradation. Nonetheless, it was shown that using light gas implantation limits the destructive effect (dewetting) while still inducing good durability (due to interface mixing). Jury Prof. Julien COLAUX (UNamur), présidentProf. Stéphane LUCAS (UNamur), promoteur et secrétaireDr Amory JACQUES (Service Public de Wallonie)Dr Philippe ROQUINY (AGC Glass Europe)Prof. Rony SNYDERS (Université de Mons)

Résumé : Impact de la voie UPR sur l’établissement du phénotype sénescent induit par les UVB Le vieillissement cutané, influencé par une combinaison de facteurs intrinsèques et extrinsèques, entraine des dommages capables d'altérer les fonctions cutanées. Parmi les facteurs extrinsèques, les rayonnements ultraviolets (UV) sont responsables du photo-vieillissement de la peau. Ces éléments conduisent notamment à une accumulation de cellules sénescentes capables de contribuer au développement de pathologies liées à l’âge, telles que les cancers cutanés. En effet, la sénescence s’accompagne de profonds changements morphologiques et moléculaires au sein de la cellule. Cela inclut notamment une modification de son sécrétome, qui s'enrichit en cytokines pro-inflammatoires, en facteurs de croissance et en enzymes remodelant la matrice extracellulaire, altérants les caractéristiques des tissus lors du vieillissement. Néanmoins, les mécanismes précis qui aboutissent au phénotype sénescent induit par les UVB restent largement inconnus.            Dans ce contexte, l’objectif principal de ce travail a été d'identifier des mécanismes moléculaires sous-jacents à l’établissement de la sénescence induite par les UVB dans des fibroblastes de derme humains normaux (NHDFs), mécanismes qui pourraient contribuer au vieillissement cutané.  In vitro, nous avons confirmé que des expositions répétées aux UVB induisent la sénescence prématurée des NHDFs et que cet état est associé à l’activation des trois branches de la voie UPR (Unfolded Protein Response) responsables du maintien de l’homéostasie du réticulum endoplasmique (RE), le premier compartiment de sécrétion. Ces observations ont été supportées par une analyse transcriptomique, révélant des éléments de régulation liés aux grandes voies de sénescence et aux fonctions du RE dans les NHDFs exposés aux UVB.    Par la suite, nous avons montré que la branche ATF6α joue un rôle central dans la survenue des biomarqueurs du phénotype sénescent induit par les UVB. En effet, l’invalidation d’ATF6α protège non seulement des changements morphologiques induits par les UVB, mais réduit le pourcentage de cellules positives pour la SA-βgalactosidase (SA-βgal), prévient la persistance des dommages à l'ADN, et modifie l'expression de facteurs majeurs du phénotype sécrétoire associé à la sénescence (SASP).    Le SASP exerçant entre autres une action pro-tumorale, nous avons cherché à évaluer si le milieu conditionné (MC) des fibroblastes exposés aux UVB et invalidé pour ATF6α pouvait impacter le potentiel de migration et d'invasion de cellules issues de mélanomes. Cependant, nous n'avons pas observé d’effets pro-migratoires ou pro-invasifs dépendants d’ATF6α.Afin de mettre en évidence un potentiel rôle d’ATF6α dans un autre processus biologique, nous avons exploité nos analyses transcriptomiques et sécrétomiques et avons identifié un possible effet d’ATF6α sur le contrôle paracrine de l’environnement cutané. Pour explorer cela, nous nous sommes concentrés sur les facteurs du SASP (cytokines et métalloprotéases) régulés par ATF6α et dont l’impact sur l’environnement tissulaire était connu. Ensuite, nous avons traité un modèle d'épiderme humain reconstruit (RHE) avec du MC issu de NHDFs exposés aux UVB ou non, et invalidés ou non pour ATF6α. Etonnement, nous avons observés que le MC des NHDFs exposés aux UVB augmente l’épaisseur du RHE ainsi que la prolifération des kératinocytes basaux, via un mécanisme dépendant d’ATF6α. Enfin, nous avons identifié l'IL8 comme un facteur paracrine majeur impliqué dans ce processus, puisque le blocage d’IL-8 par des anticorps neutralisants prévient la prolifération excessive des kératinocytes.            En conclusion, nous rapportons le rôle d’ATF6α dans la sénescence induite par les UVB ainsi que son impact sur la préservation de l'homéostasie cutanée en condition de stress notamment par la régulation de l’expression des composants du SASP. Cela suggère qu'ATF6α et ses effecteurs pourrait être des cibles prometteuses contrôlant les effets du vieillissement cutané.Abstract: Impact of the UPR pathway on the establishment of the senescent phenotype induced by UVBSkin aging, influenced by a combination of intrinsic and extrinsic factors, can result in damage that has the potential to alter skin functions. Among extrinsic factors, ultraviolet (UV) radiation is responsible for skin photoaging. These factors notably contribute to the accumulation of senescent cells which in turn can contribute to the development of age-related pathologies, including skin cancers. Indeed, senescence is characterized by profound morphological and molecular changes within the cell. This includes a modification of its secretome, which becomes enriched in pro-inflammatory cytokines, growth factors, and matrix-remodeling enzymes, altering tissue characteristics during aging. However, the exact mechanisms driving the senescent phenotype induced by UVB remain largely unknown.          In this context, the main objective of this work was to identify the underlying molecular mechanisms responsible for the establishment of UVB-induced senescence in normal human dermal fibroblasts (NHDFs), mechanisms that may play a role in skin aging.   In vitro, we confirmed that repeated exposures to UVB induce premature senescence of NHDFs and that this state is associated with the activation of the three branches of the Unfolded Protein Response (UPR), which are responsible for maintaining endoplasmic reticulum (ER) homeostasis, the primary cellular secretion compartment. These observations were supported by transcriptomic analysis, revealing regulatory elements related to major senescence pathways and ER functions in UVB-exposed NHDFs. Subsequently, we demonstrated that the ATF6α branch plays a central role in the development of the UVB-induced senescent phenotype. Indeed, the silencing of ATF6α not only protects against morphological changes induced by UVB, but also reduces the percentage of senescence-associated β-galactosidase (SA-βgal) positive cells, prevents the persistence of DNA damage, and alters the expression of major factors associated with the senescence-associated secretory phenotype (SASP).The SASP, exerting a pro-tumoral action, led us to assess whether the conditioned medium (CM) from UVB-exposed fibroblasts invalidated for ATF6α could impact the migration and invasion potential of melanoma cells. However, we did not observe any ATF6α-dependent pro-migratory or pro-invasive effects.  To highlight a potential role of ATF6α in another biological process, we further analyzed our transcriptomic and secretomic analyses and identified a possible effect of ATF6α on the paracrine control of the skin environment. To explore this, we focused on SASP factors (cytokines and metalloproteinases) regulated by ATF6α and whose impact on tissue environment was known. Subsequently, we treated a reconstructed human epidermis (RHE) model with CM from NHDFs exposed or not to UVB and invalidated or not for ATF6α. Surprisingly, we observed that the CM from UVB-exposed NHDFs increased the thickness of the RHE as well as the proliferation of basal keratinocytes, via an ATF6α-dependent mechanism. Finally, we identified IL8 as a major paracrine factor involved in this process, as blocking IL-8 with neutralizing antibodies prevented excessive proliferation of keratinocytes.  In conclusion, we report the role of ATF6α in UVB-induced senescence and its impact on the preservation of skin homeostasis under stress conditions, particularly through the regulation of the expression of SASP components. This suggests that ATF6α and its effectors could be promising targets for controlling the effects of skin aging. Jury Prof. Yves POUMAY (Département de Médecine, UNamur), présidentProf. Florence CHAINIAUX (Département de Biologie, UNamur), promotrice et secrétaireProf. Olivier PLUQUET (Canther, Université de Lille), co-promoteurProf. Isabelle PETROPULOS (Adaptation Biologique et Vieillissement, Sorbonne Université)Prof. Jérôme LAMARTINE (Laboratoire de Biologie Tissulaire et d’Ingénierie thérapeutique, Université Claude Bernard Lyon 1)Prof. Fabienne FOUFELLE (Maladies métaboliques, diabète et comorbidités, Sorbonne Université)

Jury Prof. Nathalie BURNAY (UNamur), présidenteProf. Sabine HENRY (UNamur), secrétaireDr. Florence DE LONGUEVILLE (UNamur)Prof. Nathalie MONDAIN (Université d’Ottawa)Prof. Etienne PIGUET (Université de Neuchâtel)Prof. Sane TIDIANE (Université Assane Seck/Ziguinchor) Abstract Recent attention to environmental change has highlighted its impact on rural communities, particularly in Africa, where household-level adaptations play a crucial role in larger societal responses. Current research often overlooks these small-scale, everyday adaptations and how they evolve over time, limiting our understanding of rural communities' dynamic responses to environmental changes. This study focused on households living in rural West Africa, more specifically in the region of Saint-Louis in Senegal. To capture the complexity of the household adaptation journeys, the structured timeline mapping methodology was developed, which consists of completing timelines during interviews. Timelines were collected from 39 individuals in 17 households to explore how families perceive and adapt to environmental shifts. In addition, this research reflected on the added value and necessity of interviewing multiple household members to capture diverse lived experiences and ensure a comprehensive household-level perspective.Analysis of the data categorized the adaptation journeys into four typological groups reflecting different sensitivities and adaptive capacities: (1) diversified adjusters, (2) system maintainers, (3) environmental independence strivers, and (4) opportunity-driven adapters. All groups have differentiated responses to similar environmental changes, with differences in the temporality of the response, differences in the types of adaptations, and differences in the amount and diversity of adaptations. These differences result in resilience that evolves unevenly over time. Understanding these varied adaptation pathways lead to formulate policy recommendations aimed at improving adaptive capacity, resilience, and sustainable livelihoods.

Voir l'annonce en LSFB sur YouTube.Cette thèse compare les pratiques d’action construite, souvent appelées “transferts personnels” dans la littérature scientifique francophone, en Langue des Signes de Belgique francophone (LSFB) et en français de Belgique.This dissertation compares constructed action, often called ‘personal transfer’ in the French-speaking scientific literature, in French Belgian Sign Language (LSFB) and in Belgian French. Accessibilité •    Présentation en LSFB et en français•    Questions des membres du jury et réponses du candidat en anglais et en BSL, interprétées en LSFB et en français Jury Prof. Lieven VANDELANOTTE (Président), UNamurProf. Laurence MEURANT (Promotrice, Secrétaire), UNamurProf. Philippe DE BRABANTER (Co-promoteur), ULBProf. Gabrielle HODGE, University of EdinburghProf. Darren SAUNDERS, University of ManitobaVous êtes cordialement invités à assister à cette soutenance.La proclamation sera suivie d’un drink à la Salle académique.Contact : Secrétariat admnistratif - 081/72 42 13 - evenements.lettres@unamur.be Inscription

Jury Prof. André FÜZFA (UNamur), présidentProf. Alexandre MAUROY (UNamur), secrétaireProf. Joseph WINKIN (UNamur)Prof. Raphaël JUNGERS (UCLouvain)Dr Milan KORDA (LAAS-CNRS, Toulouse)Prof. Igor MEZIC (University of California Santa Barbara) Abstract Switched systems became more and more interesting since they are conceptually closed to the description of real complex dynamics in which the state is not necessarily fixed in time but can abruptly change with the environment. In this context, not only a finite number of subsystems (said modes) are given to describe the possible state of the system, but also a switching (or commutation) law is assigned to indicate the active mode at each time.The stability theory of such systems is not intuitive since it is influenced by the commutation law, which plays a capital role.This dissertation investigates the uniform stability (i.e. stability under any commutation laws) and the switching stabilization (design of a stabilizing commutation law) problems of switched nonlinear systems.In the last decades, these problems have mainly been studied for switched linear systems and partially solved for the nonlinear case.The strategy exploited here is based on a successful tool today: the Koopman operator. This is a linear operator acting on an infinite-dimensional space of functions valued on the nonlinear system's state space. Roughly speaking, it allows one to transform a nonlinear finite-dimensional dynamics into a linear infinite-dimensional dynamics, from which one can deduce results for the original nonlinear system. More precisely, we utilize the Koopman operator framework to address switched nonlinear systems' uniform stability and stabilization problems.For the first problem, by using a Lie-algebraic solvability condition, we show that individual globally asymptotically stable nonlinear vector fields which admit a common Koopman finite-dimensional invariant subspace generate a uniformly globally asymptotically stable switched nonlinear system. In a broader context, we develop a general framework for studying the (uniform) stability of (switched) nonlinear systems on the polydisk or the hypercube. This systematic approach allows us to construct a common Lyapunov function that guarantee global uniform  asymptotic stability on the polydisk or the hypercube. We then apply this framework to derive systematic criteria for the global stability of nonlinear systems defined on the polydisk or the hypercube. Finally, for the second problem, we utilize the previously developed results to provide a  state-dependent switching stabilization strategy from  a systematic Lyapunov function of a convex combination of nonlinear vector fields.

En présence du réalisateur et de Olivier Rubbers, instigateur de cette réintroduction.  Cette projection sera suivie d'un débat en présence d'Olivier Rubbers, à l'origine du retour "quelque peu contesté" du castor dans nos contrées.PAF : 4€ (2€ pour les étudiants)Inscriptions préférables via Laurent Tallier - 0494/44 81 55 - laurent.tallier@unamur.be

The design of collective decision-making mechanisms for robot swarms engaged in tasks that require consensus among the robots is a challenging problem in swarm robotics. The complexity of this design problem increases with the number of options and the number of cues that robots have to consider to make a decision. The research work presented in this thesis addresses this challenge by exploring the potential of evolutionary robotics (ER) as a design tool for synthesising neural network controllers that underpin the robots' decision-making process. The main objective is to design individual mechanisms that support the emergence of robust, scalable, and effective collective decision-making strategies while avoiding common assumptions made in previous research. These assumptions include pre-defined correlations between environmental features and robot behaviour or the use of specific opinion formation mechanisms, such as the voter or majority rule, to update opinions.The thesis focuses on two fundamental collective decision-making scenarios: the collective perception scenario and the site selection scenario. The first scenario involves robots collectively identifying the most prevalent element in the environment, represented by the colour covering the largest portion of the arena floor. The second scenario requires the robots to collectively choose the best site among several options based on their quality. La Faculté d'Informatique de l'UNamur vous invite à la Thèse de Doctorat de Ahmed ALMANSOORI « On the Evolution of Mechanisms for Collective Decision-making in a Swarm of Robots ». Dirigée par le Prof. Elio TUCI.Devant un jury composé de :Prof. Wim VANHOOF, Président, Université de NamurProf. Elio TUCI, Promoteur, Université de NamurProf. Patrick HEYMANS, Membre interne, Université de NamurProf. Muhanad HAYDER MOHAMMED MOHAMMED, Membre interne, Université de NamurProf. Yara KHALUF, Membre externe, Université de Wageningen (Pays-Bas)Vous êtes cordialement invités à un drink, qui suivra la soutenance publique.Pour une bonne organisation, merci de donner votre réponse pour le jeudi 10 octobre au moyen de ce lien.Contact : Notaro Amelie - amelie.notaro@unamur.be

JuryProf. Guillaume BERIONNI (UNamur), présidentProf. Zineb MEKHALIF (UNamur), secrétaireProf. Catherine MICHAUX (UNamur)Prof. Noureddine NASRALLAH (Université des Sciences et Technologies - Houari Boumediene)Prof. Nacira NAAR (Université des Sciences et Technologies - Houari Boumediene)RésuméThe increasing in global energy demand and environmental concerns related to traditional energy sources necessitate the exploration of sustainable alternatives. This thesis investigates the potential of thermoelectric (TE) energy conversion using conducting polymer-based composites. Traditional TE materials, while efficient, face challenges such as toxicity and limited availability. Conducting polymers offer a promising solution due to their flexibility, processability, and tunable properties. By forming composites with materials like carbon nanotubes (CNTs) and graphene, their TE performance can be significantly enhanced. Surface treatment and functionalization are crucial for optimizing these composites and improving their efficiency.The thesis reviews the principles of thermoelectricity, including the Seebeck and Peltier effects, and the limitations of traditional TE materials, setting the stage for investigating conducting polymers as alternatives.The research methodology involves synthesizing and characterizing conducting polymer-based composites, focusing on surface treatment and functionalization techniques to enhance TE performance. Various composites incorporating graphene, CNTs, and metal oxide nanoparticles (bismuth oxide or nickel oxide) are synthesized and evaluated for their TE properties. The influence of surface modifications on composite morphology, charge transport, and TE parameters is systematically studied.The findings reveal significant improvements in TE efficiency through surface treatment and composite formation. Functionalization of graphene and CNTs enhances their compatibility with polymer matrices, improving dispersion and interfacial bonding, leading to higher electrical conductivity, reduced thermal conductivity, and ultimately, greater TE efficiency. Incorporating metal oxide nanoparticles further enhances the power factor, demonstrating the potential of hybrid composites in TE applications.Bienvenue à tous et toutes !