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See detailQuelles caractéristiques du passage à la retraite ont un impact sur la cognition du sujet âgé ? Résultats de la cohorte AMI
Grotz, Catherine ULg; Matharan, Fanny; Amieva, Hélène et al

Conference (2015, May 29)

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See detailAntitrust and The challenge of policing « moligopolists »
Petit, Nicolas ULg

Conference (2015, May 29)

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See detailApproche processuelle de la dépression : Impact de processus psychologiques l'activation ou l'évitement en fonction du sexe
Wagener, Aurélie ULg

Conference (2015, May 29)

La dépression est caractérisée par des symptômes affectifs, cognitifs et somatiques. Elle est également caractérisée par une diminution du niveau d’engagement dans des activités ce qui peut être ... [more ▼]

La dépression est caractérisée par des symptômes affectifs, cognitifs et somatiques. Elle est également caractérisée par une diminution du niveau d’engagement dans des activités ce qui peut être conceptualisé comme de l’évitement comportemental (symptôme comportemental). Il est en effet fréquent que les patients dépressifs s’engagent de moins en moins dans des activités qui leur plaisaient auparavant (voir des amis, etc.) Ce faible niveau d’activités maintient leur humeur dépressive. Cette relation entre dépression et faible niveau d’engagement dans des activités est bien établie dans la littérature scientifique mais les relations entre les processus cognitifs sous-jacents sont encore mal connues. Selon les modèles théoriques de la dépression (Beck, 2008; Lewinsohn, 1985; Watkins, 2009), cinq types de processus psychologiques (PP) sont impliqués dans la symptomatologie dépressive : les pensées négatives répétitives, les stratégies de régulation émotionnelle non-adaptées, un faible niveau de satisfaction environnementale, une image de soi négative et une tendance à l’inhibition. Nous faisons l’hypothèse que ces PP pourraient être les facteurs explicatifs de l’évitement comportemental. Par ailleurs, nous faisons également l’hypothèse que d’autres PP pourraient être considérés comme des facteurs explicatifs de l’activation comportementale : les stratégies de régulation émotionnelle adaptées, un haut niveau de satisfaction environnementale, une image de soi positive, une tendance à l’approche et un concept de soi clair. Ces PP consisteraient en des facteurs protecteurs de la dépression. Dès lors, notre objectif est d’évaluer les liens entre évitement comportemental, activation comportementale et PP. Pour ce faire, en nous basant sur le modèle de Kinderman (2013), nous avons élaboré un modèle conceptualisant l’influence que peuvent avoir les PP précités sur, d’une part, l’évitement comportemental et, d’autre part, l’activation comportementale. De plus, l’étude évalue l’adéquation de ce modèle de façon à comparer les hommes et les femmes. 477 adultes issus de populations cliniques et non-cliniques (119 hommes, 358 femmes, âge moyen = 34,25, ET = 11,85) ont complété une étude en ligne évaluant les PP (pensées négatives répétitives, stratégies de régulation émotionnelles, satisfaction environnementale, image de soi, tendance à l’inhibition/l’approche, clarté du concept de soi), l’évitement comportemental et l’activation comportementale. Différents questionnaires évaluaient chacun de ces PP. Dès lors, des scores factoriels ont été réalisés pour représenter chaque PP. Les résultats préliminaires issus d’analyses factorielles confirmatoires semblent révéler des différences entre les hommes et les femmes. Pour les hommes, une image de soi négative, des stratégies de régulation émotionnelle non-adaptées et un faible niveau de satisfaction environnementale sont liés à l’évitement comportemental alors qu’un haut niveau de satisfaction environnementale et une image de soi positive sont liés à l’activation comportementale. Pour les femmes, un faible niveau de satisfaction environnementale, des stratégies de régulation émotionnelle non-adaptées et des pensées négatives répétitives sont liées à l’évitement comportemental alors qu’un haut niveau de satisfaction environnemental et une image de soi positive sont liées à l’activation comportementale. La collecte des données étant toujours en cours, les résultats globaux seront présentés durant le congrès. Les implications cliniques de ces résultats seront discutées telles que la pertinence de travailler sur le niveau de satisfaction environnementale. [less ▲]

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See detailTowards an experiment based protocol for extracting and identifying residues
Cnuts, Dries ULg; Rots, Veerle ULg

Conference (2015, May 29)

Residue analysis has recently become a widely applied method in reconstructing the lifecycle of prehistoric stone tools. The identification of residues is traditionally based on the distinctive ... [more ▼]

Residue analysis has recently become a widely applied method in reconstructing the lifecycle of prehistoric stone tools. The identification of residues is traditionally based on the distinctive morphologies of the residue fragments by means of light microscopy. The majority of residue fragments, however, tend to have an amorphous structure and are therefore not easy to identify. In addition, some residue categories can only be detected by using transmitted light microscopy, which requires the extraction of residues from the tool’s surface. Yet another challenge is to determine whether the residues were deposited on the tool’s surface as a result of use or due to other processes. Here we present the results of an experimental study that addresses these methodological issues. Stone tools from a new experimental reference collection were used to test 6 different analytical methods: the observation of residues on stone tools with incident light microscopy, dry sampling using tweezers and brushes, wet sampling with micropipettes using distilled water and a tri-mixture of acetonitrile, ethanol and water, and extraction with an ultrasonic scaler or bath. The experiments demonstrate that the choice of a particular extraction procedure may influence the amount and types of residues that are extracted. This implies that the analytical method has an impact on the results of a residue analysis. Building on these data, we designed a new protocol, which was subsequently submitted to blind testing in order to test its accuracy and precision. Certain key attributes were also identified that may prove useful in distinguishing between use-related and natural residues. We discuss the importance of adapting analytical protocols to the research question of the study. [less ▲]

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See detailToward a more precise terminology for impact damage and an improved understanding of hunting weapons: First results from a large scale systematic experiment
Coppe, Justin ULg; Rots, Veerle ULg

Conference (2015, May 29)

Projectile points have recently taken an important place in debates on the complexity of Palaeolithic human behaviour. While the appearance of hunting weapons in the archaeological record was an important ... [more ▼]

Projectile points have recently taken an important place in debates on the complexity of Palaeolithic human behaviour. While the appearance of hunting weapons in the archaeological record was an important element in the past, current discussions focus a lot on the appearance of particular hunting methods. Distinctions are made between simple and complex weaponry, the latter assumed to be linked with modern humans only. While most of the identifications of hunting weapons in the archaeological record rely on the examination of so-called diagnostic impact damage, no reliable reference yet exist for distinguishing between hunting methods. We present the first results of a large-scale and systematic experiment that intends to address hunting weapons in a systematic way. A thorough survey of the literature has highlighted some existing ambiguity in current terminological frameworks for describing impact fractures. Based on our experiments, we propose some attributes that may be relevant for improving these terminologies. Attention will also be devoted to the design and conceptual framework of our experimental program and to some first results concerning the essential variables influencing damage formation. The overall goal is to improve our understanding of the different fracture phenomena and their variability in order to enhance the reliability of the identification of hunting weapons and perhaps of their projecting mode. [less ▲]

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See detailIs Büchi's theorem useful for you?
Rigo, Michel ULg

Conference (2015, May 28)

Almost a century ago, Presburger showed that the first order theory of the natural numbers with addition is decidable. Following the work of Büchi in 1960, this result still holds when adding a function ... [more ▼]

Almost a century ago, Presburger showed that the first order theory of the natural numbers with addition is decidable. Following the work of Büchi in 1960, this result still holds when adding a function $V_k$ to the structure, where $V_k(n)$ is the largest power of $k\ge 2$ diving $n$. In particular, this leads to a logical characterization of the $k$-automatic sequences. During the last few years, many applications of this result have been considered in combinatorics on words, mostly by J. Shallit and his coauthors. In this talk, we will present this theorem of Büchi where decidability relies on finite automata.Then we will review some results about automatic sequences or morphic words that can be proved automatically (i.e., the proof is carried on by an algorithm). Finally, we will sketch the limitation of this technique. With a single line formula, one can prove automatically that the Thue-Morse word has no overlap but, hopefully, not all the combinatorial properties of morphic words can be derived in this way. [less ▲]

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See detailQuelle place accorder aux écritures de la réception dans le contexte de la formation initiale? Du comportement des futurs enseignants face à des médiations de la lecture à l'élaboration de dispositifs de formation
De Croix, Séverine ULg; Ledur, Dominique

Conference (2015, May 28)

L’exploitation des écritures de la réception en formation initiale des enseignants fait aujourd’hui l’objet d’un large consensus (Joole, 2013 ; Chabanne & Dufays, 2011; Mazauric, Fourtanier & Langlade ... [more ▼]

L’exploitation des écritures de la réception en formation initiale des enseignants fait aujourd’hui l’objet d’un large consensus (Joole, 2013 ; Chabanne & Dufays, 2011; Mazauric, Fourtanier & Langlade, 2011 ; Vanhulle & Schillings, 2004). Nous souhaitons nous interroger sur les moyens, les objectifs et les effets attendus de cette exploitation (axe 4 de l’appel à communications). Le présent projet porte, dans un premier temps, sur l’observation des réactions d’une centaine de futurs enseignants de français du secondaire, tous niveaux confondus, face à un corpus de médiations écrites de la lecture, produites par des élèves de 12 à 18 ans, lecteurs experts et en difficulté. Ces écrits relèvent de genres diversifiés (journaux de lecture, notes critiques, traces collectées à l’occasion d’un dévoilement progressif, réponses à des questions, etc.) et de statuts différents (écrits de travail ou productions finales susceptibles d’être évaluées). Les consignes d’analyse devaient conduire les étudiants à repérer les éventuelles difficultés des lecteurs (ou leurs réussites), à reconstruire les tâches, à relever différents positionnements face aux textes, etc. Nos constats mettent notamment en évidence une tendance à investir ces écrits de façon normative (prédominance des difficultés du lecteur, notamment linguistiques, au détriment d’une prise en compte des difficultés générées par les textes et/ou les tâches scolaires) et une faible conscience de la complexité de l’activité de compréhension/interprétation. L’analyse des données collectées à l’occasion de ce travail incite, dans un deuxième temps, à privilégier quatre directions pour apprendre aux futurs maitres de lecture à lire des écrits de la réception et pour les amener par ce biais à développer des compétences et gestes professionnels en didactique de la lecture littéraire : modéliser l’activité de compréhension/interprétation, identifier les éventuelles difficultés de lecture, sélectionner des textes pour la classe et les associer à des médiations adaptées, percevoir les caractéristiques et les visées des tâches (y compris anticiper les éventuels malentendus générés par celles-ci et organiser leur progression). Ces axes d’intervention seront illustrés par quelques exemples de dispositifs de formation. [less ▲]

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See detailThe hot Jupiter WASP-­121 b: A planet heading towards its doom
Delrez, Laetitia ULg

Conference (2015, May 28)

We present here the discovery by the WASP-South survey, in close collaboration with the Euler and TRAPPIST telescopes, of WASP-121 b, a new remarkable short-period transiting hot Jupiter. WASP-121 b is a ... [more ▼]

We present here the discovery by the WASP-South survey, in close collaboration with the Euler and TRAPPIST telescopes, of WASP-121 b, a new remarkable short-period transiting hot Jupiter. WASP-121 b is a very inflated (1.86 Rjup) Jupiter-mass (1.18 Mjup) planet that transits every 1.27 days a bright active F6V star. A notable property of WASP-121b is that its orbital semi-major axis is only 15% larger than its Roche limit, which suggests that the planet might be close to tidal disruption. Furthermore, its large size and extreme irradiation (7.1 10^9 erg s^-1 cm^-2) make it an excellent target for atmospheric studies via secondary eclipse observations. Using the TRAPPIST robotic telescope, we indeed detect its thermal emission in the z’-band at better than ~4sigma, the measured occultation depth being 603+-130 ppm. This measurement is a first for a ground-based 60cm telescope. Finally, from a measurement of the Rossiter-McLaughlin effect with the CORALIE spectrograph, we infer a sky-projected spin-orbit angle of 257.8+-6 deg. This result indicates a significant misalignment between the spin axis of the host star and the orbital plane of the planet, the planet being in a nearly polar orbit. [less ▲]

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See detailTool use and hafting in the Middle Palaeolithic of Northern Africa An on-going use-wear analysis on the Mousterian/Aterian assemblages of Ifri n’Ammar (Morocco)
Tomasso, Sonja ULg; Rots, Veerle ULg

Conference (2015, May 28)

The so-called “Aterian Culture” has received attention since the early days of prehistoric archaeology in Northern Africa. Several definitions were proposed, which triggered a debate around this cultural ... [more ▼]

The so-called “Aterian Culture” has received attention since the early days of prehistoric archaeology in Northern Africa. Several definitions were proposed, which triggered a debate around this cultural concept. In particular the presence of the tanged tools was a crucial element in these debates and the tangs were considered to potentially represent the earliest indications of hafting, or at least of intentional morphological adaptations in view of hafting. In contrast to numerous typological and technological studies of Aterian and Mousterian assemblages, use-wear analyses have been scarce up until today. However, for a better understanding of several aspects of these Middle Palaeolithic “cultures”, functional data needs to be taken into consideration. Given the issue of tanged pieces, the potential of such detailed studies on production, hafting and use is high. In this paper, the first results will be presented of an on-going use-wear analysis on tools from the Aterian/Mousterian assemblages of Ifri n’Ammar. This rock shelter presents an ideal case thanks to its particularly rich and well preserved stratigraphy. Around 200 artefacts have been selected up to now, based on their degree of preservation and without restrictions on the level of the tool types. Artefacts were examined macroscopically and microscopically in a search for evidence of their production, hafting and use and an experimental program was set up. Archaeological interpretations are based on new experiments, as well as on the existing large experimental reference collection available at TraceoLab at the University of Liège. The long-term goal of the study is to use a functional approach to answer questions related to lithic assemblage variability. At Ifri n’Ammar, it is clear that the tangs occur on a variety of tools. Due to the presence of tangs in the Aterian and their absence in the Mousterian, it can be hypothesized that there was a shift in hafting techniques between the two cultures/periods. In order to understand whether this change was triggered by functional, cultural, or environmental factors, more functional data is clearly needed. [less ▲]

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See detailLe donné phénoménal de Tim Crane
Gauvry, Charlotte ULg

Conference (2015, May 28)

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See detailThe more you know...........various approaches in the analysis of tools from Liang Bua, Flores Indonesia
Lentfer, Carol ULg; Stephenson, Birgitta; Cnuts, Dries ULg et al

Conference (2015, May 28)

Chipped stone flakes from sedimentary deposits from the Liang Bua site, Flores, Indonesia have been found in association with faunal remains and skeletal remains identified as Homo floresiensis. Use-wear ... [more ▼]

Chipped stone flakes from sedimentary deposits from the Liang Bua site, Flores, Indonesia have been found in association with faunal remains and skeletal remains identified as Homo floresiensis. Use-wear and well-preserved organic residues on these flakes provide an opportunity to understand subsistence and behaviour of Homo floresiensis by determining how they were manipulated and what they were used for. This paper describes the analytical techniques including various microscope and staining methodologies used in residue analyses. It compares the efficacy and describes the outcome of these techniques in relation to the functional analysis of the Liang Bua lithic assemblage. [less ▲]

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See detailStone tool hafting and use in the European Upper Palaeolithic: the first results of the analysis of Gravettian tools from Hohle Fels
Taipale, Noora ULg; Rots, Veerle ULg

Conference (2015, May 28)

European Upper Palaeolithic lithic assemblages have been so far defined largely on a typological or technological basis, while extensive studies that would utilise the full potential of microwear analysis ... [more ▼]

European Upper Palaeolithic lithic assemblages have been so far defined largely on a typological or technological basis, while extensive studies that would utilise the full potential of microwear analysis have been few. This contribution presents the first results of an ongoing PhD project dedicated to the variability in stone tool use and hafting in the Upper Palaeolithic of Central and Western Europe. The aim of the project is to understand the development as well as regional patterns in tool hafting and use in the Gravettian and Magdalenian, and thus better explain the observed morphological and technological shifts. For this purpose, samples of tools from five European key sites with well-dated sequences (Hohle Fels, Geißenklösterle, Vogelherd, Maisières-Canal, and Abri Pataud) will be analysed giving a special emphasis on hafting traces. The study wishes to promote functional analysis as an integral part of technological studies, not as a mere side note. The German cave site Hohle Fels is used here as a case study to illustrate the potential of this kind of approach. The first results of the analysis of the site’s Gravettian material will be put into a wider context of earlier published results as well as preliminary observations made on the other assemblages included in the present study. Building on these results, the impact of tool hafting and use on the morphology of Gravettian lithic implements will be discussed. [less ▲]

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See detailAn ALE meta-analysis on the neural correlates of personal goal processing during episodic future thoughts and mind-wandering
Stawarczyk, David ULg; D'Argembeau, Arnaud ULg

Conference (2015, May 28)

The ability to project oneself into the future is a multi-determined mental faculty that depends on various cognitive processes supported by an extended set of brain regions. The aim of the present study ... [more ▼]

The ability to project oneself into the future is a multi-determined mental faculty that depends on various cognitive processes supported by an extended set of brain regions. The aim of the present study was to examine a crucial component of future thinking—personal goal processing—and to determine its neural correlates during both experimentally directed mental time travel towards the future and mind-wandering, a form of spontaneous thoughts characterized by a prospective bias towards upcoming events. To address this question, we performed three distinct ALE meta-analyses of brain imaging studies on episodic future thinking, mind-wandering, and personal goal processing. We then examined the commonalities and differences in brain activity between these three areas of research. The results showed that the three domains activated a common set of brain regions within the default network including the posterior inferior parietal cortex, posterior cingulate cortex, lateral temporal lobe, and, most notably, the medial prefrontal cortex. Differences in activation were also observed, and the medial prefrontal cortex was more activated during personal goal processing than the other two domains. These findings suggest that the medial prefrontal cortex mediates the processing of personal goals during both episodic future thinking and mind-wandering. [less ▲]

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See detailHeterogeneity of multitasking abilities in schizophrenia.
Laloyaux, Julien ULg; Van der Linden, Martial ULg; Laroi, Frank ULg

Conference (2015, May 28)

Difficulties in everyday life activities are core features of persons diagnosed with schizophrenia, and in particular for those activities requiring multitasking capacities. Multitasking refers to ... [more ▼]

Difficulties in everyday life activities are core features of persons diagnosed with schizophrenia, and in particular for those activities requiring multitasking capacities. Multitasking refers to activities (e.g. preparing a meal) where the person has to: (a) carry out and alternate between different tasks that vary in terms of priority, difficulty and duration; (b) define the tasks’ targets; (c) and face unexpected problems during the realization of these tasks. Moreover, schizophrenia is characterized by a great heterogeneity in regard to their everyday life difficulties and cognitive functioning. At present, patients’ multitasking capacities have not been adequately examined in the literature due to an absence of suitable assessment strategies. We thus recently developed a computerized real-life activity task designed to take into account the complex and multitasking nature of certain everyday life activities where participants are required to prepare a room for a meeting (i.e. the Computerized Meeting Preparation Task, CMPT). The aim of this study was to examine the multitasking abilities in persons diagnosed with schizophrenia and in particular the existence of subgroups of patients in regard to their performances on cognitive measures and on the CMPT. Sixty-two patients diagnosed with schizophrenia and 39 paired healthy controls completed the CMPT and a cognitive battery. The results reveal that the CMPT possesses good sensitivity and suggest three underlying constructs of multitasking (Memory, Planning and Intent), which were found to be underpinned by several cognitive functions and multitasking aspects. Moreover, cluster analyses revealed subgroups of patients differing in terms of their cognitive and CMPT performances. Taken together, these results show the need for a cognitive model of multitasking abilities in persons diagnosed with schiozphrenia. Taken together, this cognitive model and the CMPT, could be a good basis for cognitive interventions of multitasking abilities in schizophrenia. Finally, the results underline the heterogeneity of schizophrenia. [less ▲]

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See detailControl of nuclear sample polarization using optical pumping and radio-frequency methods
Lenaers, Florence ULg; Glover, Rohan ULg; Bastin, Thierry ULg

Conference (2015, May 27)

Laser-cooled and trapped radioactive isotopes are now being used to probe the properties of the weak interaction in nuclear beta decay. In this context, it is essential that one be able to control the ... [more ▼]

Laser-cooled and trapped radioactive isotopes are now being used to probe the properties of the weak interaction in nuclear beta decay. In this context, it is essential that one be able to control the nuclear polarization of the atomic samples. We present two polarization/depolarization schemes for argon-35, whose mirror transition to chlorine-35 is a particularly sensitive candidate for precision measurements in nuclear beta decay. [less ▲]

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See detailValidation d'une méthode d'analyse quantitative de l'équol par UPLC®-MS/MS dans le lait de vache - Application aux laits commercialisés en Wallonie (Belgique)
Daems, Frédéric ULg; Lognay, Georges ULg; Romne, Jean-Michel et al

Conference (2015, May 27)

Dans le cadre d’un projet intitulé «PhytoHealth », une méthode d’analyse quantitative de l’équol dans le lait a été développée et validée selon les recommandations de l’EMA/CVMP/VICH/463202/2009. Celle-ci ... [more ▼]

Dans le cadre d’un projet intitulé «PhytoHealth », une méthode d’analyse quantitative de l’équol dans le lait a été développée et validée selon les recommandations de l’EMA/CVMP/VICH/463202/2009. Celle-ci est constituée d’une étape d’hydrolyse enzymatique, suivie d’une double extraction liquide/liquide et d’une analyse par chromatographie liquide ultra performante couplé à un spectromètre de masse en tandem (UPLC®-MS/MS). Une fois les différents paramètres tels que la fiabilité, sensibilité et/ou robustesse de la méthode confirmées, celle-ci a permis, pour la première fois, d’estimer la teneur en équol d’ échantillons de laits commercialisés en Wallonie. Une Cinquantaine de laits ont été prélevés aléatoirement dans les commerces durant une période définie. Tous les échantillons possédaient une teneur en équol ≥ 10ng.mL-1. En comparant les valeurs moyennes, on a constaté qu’il n’y avait pas de différence entre les 4 catégories de laits analysés (entier, demi-écrémé, écrémé et cru). Par contre, une différence hautement significative a pu être observée entre les laits provenant de la filière biologique et ceux de la filière conventionnelle. Dans le premier cas, les teneurs varient entre 10 et 50 ng.mL-1 par contre, dans le second, elles varient entre 70 et 130 ng.mL-1. Cet impact de la filière biologique sur la teneur en équol dans les laits a pu être confronté à d’autres études européennes et confirmé. [less ▲]

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See detailTel Quel, Change et Poétique en 1970 : "l'affaire de Lausanne"
Lorent, Fanny ULg

Conference (2015, May 27)

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See detailDense-lineability in classes of ultradifferentiable functions
Esser, Céline ULg

Conference (2015, May 27)

The Denjoy-Carleman classes are spaces of smooth functions which satisfy growth conditions on their derivatives defined through weight sequences. In this talk, given a Denjoy-Carleman class E of Beurling ... [more ▼]

The Denjoy-Carleman classes are spaces of smooth functions which satisfy growth conditions on their derivatives defined through weight sequences. In this talk, given a Denjoy-Carleman class E of Beurling type that strictly contains another non-quasianalytic class F of Roumieu type, we handle the question of knowing how large the set of functions in E that are nowhere in the class $F$ is. In particular, we prove the dense-lineability of the set of functions of $E$ which are nowhere in F. Consequences for the Gevrey classes are also given. We extend then these results to the case of classes of ultradifferentiable functions defined imposing conditions on their Fourier Laplace transform using weight functions. [less ▲]

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See detailApplication du plan d’expérience de Box-Behnken et de la méthodologie des surfaces de réponses pour optimiser une méthode de quantification de phyto-œstrogènes dans les fourrages
Daems, Frédéric ULg; Lognay, Georges ULg; Romnee, Jean-Michel et al

Conference (2015, May 27)

Dans le cadre d’un projet de valorisation des prairies, intitulé « PhytoHealth », une méthode d’analyse quantitative constituée d’une étape d’extraction à l’aide d’un bain à ultrasons, suivi d’une ... [more ▼]

Dans le cadre d’un projet de valorisation des prairies, intitulé « PhytoHealth », une méthode d’analyse quantitative constituée d’une étape d’extraction à l’aide d’un bain à ultrasons, suivi d’une hydrolyse enzymatique et d’une analyse par UPLC®-MS/MS a été développée pour assurer le dosage de phyto-œstrogènes dans les fourrages. Pour alléger l’optimisation de la préparation des échantillons, la méthodologie des surfaces de réponses a été utilisée. Un plan d’expérience de Box-Behnken a été appliqué aux étapes d’extraction et d’hydrolyse. Parmi les différents facteurs pris en compte, les impacts de la nature du solvant utilisé lors de l’extraction ainsi que la température et le pH lors de l’hydrolyse, ont clairement pu être mis en évidence. L’ensemble des données générées a également permis de définir des conditions optimales d’extraction et d’hydrolyse pour chacun des composés. Ces conditions n’étant pas identiques pour chacun d’entre eux, un compromis a été trouvé afin de pouvoir analyser l’ensemble de ces composés simultanément. L’ensemble de la méthode a ensuite été validée selon les recommandations de l’EMA/CVMP/VICH/463202/2009, pour confirmer sa fiabilité et robustesse. Cette dernière, combinée au model d’ensilage en sacs sous vide, a permis pour la première fois de suivre la cinétique d’évolution de 4 phyto-œstrogènes (daidzéine, génistéine, formononétine et biochanin A) durant une période d’ensilage. [less ▲]

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See detailA stochastic multiscale analysis for MEMS stiction failure
Hoang Truong, Vinh ULg; Wu, Ling ULg; Golinval, Jean-Claude ULg et al

Conference (2015, May 26)

Stiction is a major failure in microelectromechanical system (MEMS) devices in which two contacting surfaces can remain stuck together because of the adhesive forces, such as van der Waals forces and ... [more ▼]

Stiction is a major failure in microelectromechanical system (MEMS) devices in which two contacting surfaces can remain stuck together because of the adhesive forces, such as van der Waals forces and capillary forces. Stiction is a multiscale problem which is characterized by three different lengths: the MEMS device characteristic length, the roughness of the contacting surfaces, and the distance range of the adhesive forces. Because MEMS surfaces roughness and adhesive force distances are of comparable scales, the randomness in the contacting surfaces can result in important uncertainties on the interacting forces, and in turn lead to a scatter in the MEMS structural behavior. The purpose of this work is to quantify the uncertainties on the macro stiction behavior of a MEMS structure due to the randomness in its contacting surfaces. A full analysis, such as the combination of a Monte-Carlo simulation to generate random surfaces combined with finite element (FE) analyses to model the stiction behavior, is expensive in terms of the computational cost due to the difference in the scales between the macro characteristic length and the distance range of the adhesive forces. Thus, in this work, we develop a stochastic multiscale analysis. At the micro scale, the uncertainties in the interacting forces between two rough surfaces are investigated. The power spectral density function of the surface is characterized from experimental topology measurements, and interacting surfaces are then generated as Gaussian random surfaces. For each generated random surface, the interacting adhesive forces are calculated by using a modified Dejarguin-Muller-Toporov (DMT) model. The resulting adhesive contact forces can be integrated using the finite element method at the structural scale by associating to each discretized contacting point a sampled surface. We then use the Monte-Carlo method to quantify the uncertainties in the stiction behavior of the MEMS device. [less ▲]

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See detailDe la spécification à la création de nouvelles catégorisations sociales: Le cas de francophones vivant en Flandre et de néerlandophones vivant en Wallonie
Dassargues, Alix ULg

Conference (2015, May 26)

Nos recherches doctorales visent à étudier la manière dont des individus en situation d’allophonie « illégitime » se catégorisent socialement. Puisqu’aucune catégorie identitaire légitime (c.-à-d ... [more ▼]

Nos recherches doctorales visent à étudier la manière dont des individus en situation d’allophonie « illégitime » se catégorisent socialement. Puisqu’aucune catégorie identitaire légitime (c.-à-d. institutionnalisée par les dictionnaires, les médias, les politiciens ou autres instances légitimatrices (Bourdieu 1982)) ne rend compte de la situation de francophones vivant en Flandre (région belge unilingue néerlandophone) et de néerlandophones vivant en Wallonie (région belge unilingue francophone excepté une petite communauté germanophone institutionnellement reconnue et territorialisée), ces individus conceptualisent le champ social de façon originale afin qu’il corresponde à leurs propres expériences de vie (Harder 2010 : 18). En se basant sur des principes tels que la légitimité d’un lexème dans l’espace discursif ou encore le caractère idiolectal ou non d’une catégorisation, nous nous proposons d’observer les modes de conceptualisation de l’identité par des locuteurs particulièrement aptes à formuler des catégorisations originales du champ social puisque leurs expériences de vie ne font pas l’objet de catégorisations légitimes. À partir de transcriptions d’entretiens semi-directifs, nous avons examiné le discours de témoins afin d’analyser leurs conceptualisations du champ social à travers les catégorisations qu’ils emploient. Nous prenons en compte les catégories légitimes et illégitimes citées dans les témoignages selon leur institutionnalisation (présence ou non dans les dictionnaires et dans les discours médiatiques) et la manière dont elles sont considérées par les locuteurs (catégorie considérée comme légitime ou non par les locuteurs). De la sorte, une typologie de nouvelles catégorisations identitaires a pu être établie sur la base d’une analyse linguistique : spécification d’un lexème légitime par une proposition relative , spécification d’un signifié par un redoublement de certains signifiants légitimes , spécification d’un signifié par l’instauration d’une gradation dans l’adéquation avec une catégorie légitime (stéréotype institutionnalisé) , modifications de signifiés dans des catégorisations légitimes , création de nouvelles catégorisations à partir d’adjectifs et de lexèmes légitimes , création de métaphores en transposant l’expérience d’un domaine conceptuel des catégories sociales (cf. Lakoff & Johnson 1980). Cette recherche interdisciplinaire suggère que la construction de sens s’établit à partir d’autres connaissances déjà organisées entre elles (Harder 2010:113) et partagées par une communauté d’individus. En choisissant le thème ambitieux de l’identification (ou la catégorisation) de soi et des autres, cette recherche permet également de transposer les connaissances de la linguistique cognitive au domaine social. Ainsi, elle confirme notamment que le modèle sémantique basé sur un prototype (Rosch 1978; Lakoff 1987) est adéquat pour rendre compte de la construction individuelle du sens dans le champ social. [less ▲]

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See detailPropagation of uncertainties in the modelling of MEMS resonators (using a 3-scale probabilistic approach)
Lucas, Vincent ULg; Wu, Ling ULg; Golinval, Jean-Claude ULg et al

Conference (2015, May 26)

In order to ensure the accuracy of MEMS vibrometers, the first resonance frequency should be predicted at the design phase. However, this prediction is subjected to randomness: there is a scatter in the ... [more ▼]

In order to ensure the accuracy of MEMS vibrometers, the first resonance frequency should be predicted at the design phase. However, this prediction is subjected to randomness: there is a scatter in the reached value resulting from the uncertainties involved in the manufacturing process. The purpose of this work is to take into account these uncertainties of the microstructure. The objective is a non-deterministic model that can be used since the design stage. The material is the source of uncertainties: the beam resonator is made of a polycrystalline material in which each grain has a random orientation. Solving the problem with a full direct numerical simulation combined to a Monte-Carlo method allows the probability density function of the resonance frequency to be computed. However this methodology is computationally expensive due to the number of degrees of freedom required to study one sample, motivating the development of a computationally efficient method. Towards this end a 3-scales stochastic model for predicting the resonance frequency of a micro-beam made of a polycrystalline linear anisotropic material is described. At the lower scale, we model the micro-structure with micro-volume elements. Due to the small-scale involved, the representativity of these micro-volume elements is not achieved and thus Statistical Volume Elements (SVE) are considered. These SVEs are generated under the form of a Voronoï tessellation, each grain being assigned a random orientation. Computational homogenization is applied over the SVEs, along with a Monte-Carlo procedure, to obtain a stochastic characterization of the elasticity tensor at the second scale of interest, the meso-scale. The spatial correlation between SVEs is also estimated. A generator based on spectral methods is implemented. Afterwards, using a stochastic finite element method, these meso-scale uncertainties are propagated by taking account of the spatial correlation up to the higher scale to predict the probabilistic behavior of the MEMS resonator. [less ▲]

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See detailVenus nightglow intensity and solar activity: any correlation?
Soret, Lauriane ULg; Gérard, Jean-Claude ULg

Conference (2015, May 26)

We examine if any correlation is observed between the brightness of the O2 nightside airglow and the EUV solar irradiance using the full database of VIRTIS IR images. We conclude that, as was the case for ... [more ▼]

We examine if any correlation is observed between the brightness of the O2 nightside airglow and the EUV solar irradiance using the full database of VIRTIS IR images. We conclude that, as was the case for the NO airglow observed during the Pioneer Venus mission, no response to solar activity is observed. [less ▲]

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See detailSensitivity and vulnerability to groundwater overexploitation by a ‘pressure state impact’ and process based approach
Beaujean, Jean; Lemieux, Jean-Michel; Therrien, René et al

Conference (2015, May 26)

A methodology is developed for proposing a groundwater vulnerability assessment in a Pressure-State-Impact causal chain that is familiar to decision makers. The ‘Driver Pressure State Impact Response’ ... [more ▼]

A methodology is developed for proposing a groundwater vulnerability assessment in a Pressure-State-Impact causal chain that is familiar to decision makers. The ‘Driver Pressure State Impact Response’ (DPSIR) framework, for describing interactions between society and the environment, defines a chain of Drivers that exert Pressures on the State of a given resource, such as groundwater, which then generates an Impact that will require an appropriate Response (Kristensen, 2004). The method is here based on the calculation of sensitivity coefficients for a user-defined groundwater state for which several physically-based indicators are proposed. These sensitivity coefficients reflect the easiness with which the groundwater state transmits pressures into impacts. They are grouped into a vulnerability matrix of pressures and impacts that quantify vulnerability for every combination of causal links identified in the DPSIR chain. For that reason, the sensitivity coefficients are converted to vulnerability, using the concept of ‘transgressing a given threshold’, which is commonly used in socioeconomic sciences (Luers et al. 2003). The concept of ‘rising above a given concentration threshold’ can be used for groundwater quality issues. The concept of ‘falling below a given piezometric head threshold’ can be used for groundwater quantity issues as aquifer overexploitation problems. Outside the careful selection of the sensitivity analysis method that can significantly influence the computational effort (Beaujean et al., 2013), emphasis is given to the illustration of the general methodology on a simple groundwater quantity case (of an alluvial aquifer with concerns related to water supply) demonstrating the potential use of this general and physically based vulnerability assessment method. While the methodology is general, the choice of causal chains has to be made prior to the calculation. The vulnerability is also related to a damaged state and is related to the ‘distance’ between the current state and a given threshold. This choice is arbitrary such that the vulnerability is sensitive to the choice of the threshold. [less ▲]

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See detailProcess-based method for groundwater resource vulnerability mapping with regards to solute contamination at the surface
Popescu, Cristina; Brouyère, Serge ULg; Orban, Philippe ULg et al

Conference (2015, May 26)

Numerous groundwater vulnerability methods have been developed taking into consideration a variable number of factors. The most common techniques are based on calculation of an index expressing the ... [more ▼]

Numerous groundwater vulnerability methods have been developed taking into consideration a variable number of factors. The most common techniques are based on calculation of an index expressing the protective effect of underground formations overlying the groundwater resource. However, it has been shown that different overlay and index methods applied to the same system can yield dramatically dissimilar results (among others, Gogu et al., 2003). The limitation of most of these methods is related to their use of a qualitative definition of groundwater vulnerability, as opposed to a definition based on a quantitative description of contaminant migration. A process-based point of view is proposed and based on three factors describing a pollution event (Brouyère et al., 2001): (1) the transit time from the source to the target, (2) the duration of the contamination breakthrough at the target, (3) the ratio between the maximum concentration at the target to the released concentration at the contamination source. The assessment can then be based on the impulse response at the ‘target’ to a Dirac-type solicitation (point, unit mass, instantaneous source of pollution), considering only physical hydrodispersive processes for intrinsic vulnerability and both physical and biochemical processes for specific vulnerability. The breakthrough curve obtained after a vertical transfer through the overlying layers can be computed pixel by pixel. Automatically processing the columns with identical characteristics, 1D partially saturated flow and solute transport computations are performed. Different maps are obtained for the three above mentioned factors. On the basis of these results, different vulnerability maps can be built according to the weighting coefficients agreed by the local community or decision makers. This concept allows a clear distinction between conventional aspects and process-based results in the building of a final vulnerability indicator. This methodology has the further advantage to consider the possible impact of runoff conditions occurring at the land surface and possibly leading to lateral contamination of groundwater through downstream preferential infiltration features. To solve this problem, Popescu et al. (2004 & 2008) and Dassargues et al. (2009) proposed a method for quantifying a lateral “dangerosity” coefficient using runoff coefficients based on land use, slopes, and soil properties. A test application is illustrated on a case-study located in a limestone basin in Belgium. [less ▲]

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See detailAbout the Regularity of Cantor's Bijection
Simons, Laurent ULg; Nicolay, Samuel ULg

Conference (2015, May 25)

In 1878, Cantor proved that there exists a one-to-one correspondence between the points of the unit line segment [0,1] and the points of the unit square [0,1]². Since this application is defined via ... [more ▼]

In 1878, Cantor proved that there exists a one-to-one correspondence between the points of the unit line segment [0,1] and the points of the unit square [0,1]². Since this application is defined via continued fractions, it is very hard to have any intuition about its smoothness. In this talk, we explore the regularity and the fractal nature of Cantor's bijection, using some notions concerning the metric theory and the ergodic theory of continued fractions. This talk is based on a joint work with S. Nicolay. [less ▲]

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See detailCharles Juliet : Du portrait a-posteriori à l’écriture de soi L’adresse à la mère comme tentative de désenfouissement dans Lambeaux
Vandormael, Thomas ULg

Conference (2015, May 25)

Lambeaux propose un diptyque de portraits. Dans la première partie, celui de la mère biologique. Dans la seconde, celui de l’auteur lui-même et au sein de celui-ci, enfin, le portrait de la mère adoptive ... [more ▼]

Lambeaux propose un diptyque de portraits. Dans la première partie, celui de la mère biologique. Dans la seconde, celui de l’auteur lui-même et au sein de celui-ci, enfin, le portrait de la mère adoptive. La dimension vocative explicite de la narration en constitue à la fois l’originalité et le paradoxe. Le recours au « Tu » dans l’ensemble du texte fait advenir une poétique de l’adresse en laquelle se cristallise la spécificité du récit de filiation propre à l’autofiction de la littérature contemporaine : différent du simple devoir de mémoire ou encore de la - très en vogue - commémoration, il se situe plutôt du côté de la restitution, à laquelle il y a deux sens à donner : à la fois reconstituer ce qui fut et s’est défait, et rendre leur existence à ceux qui s’en sont trouvés dépouillés en faisant apparaître ce qui demeure enfoui et dont on n’a pu hériter. Pour répondre au silence d’une mère qu’il n’a pas connue et qui elle-même n’a pas pu s’exprimer, faute d’accès au langage ou d’une présence pour l’écouter, Juliet choisit l’instantané et l’immédiateté d’un discours d’interpellation au présent et la forme du dialogue avec les morts, forcément toujours en partie déjà voué à l’échec. Dès lors, notre propos souhaite interroger comment le choix du vocatif permet un dédoublement fécond du sujet,faisant advenir une relation de soi à soi qui déjoue les processus classiques de l'autobiographie. [less ▲]

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See detailGestion des déchets nucléaires en France et en Belgique: Quelle place pour la critique ?
Parotte, Céline ULg

Conference (2015, May 25)

Depuis les années 1970, avec la multiplication des controverses scientifiques (Callon, Lascoumes et Barthe 2001), souvent liées à des mouvements pacifistes en environnementalistes ; nous assistons à la ... [more ▼]

Depuis les années 1970, avec la multiplication des controverses scientifiques (Callon, Lascoumes et Barthe 2001), souvent liées à des mouvements pacifistes en environnementalistes ; nous assistons à la naissance d’un flux d’incertitude et de critique politico-sociale, dirigée principalement vers le monde scientifique, sa production et ses hésitations. Il est malaisé de prévoir si cela mènera à une réelle désolidarisation des notions de science, technologie et progrès, mais il reste à supposer que cette critique permettra une gestion plus réflexive des effets majeurs du développement scientifique et technologique (Schot et Rip 2009). En d’autres termes, bien que les liens entre les idéologies du progrès et de la technologie restent très souvent puissants et non remis en question, on assiste au même moment à une critique sociale des conséquences sur le processus de gestion des choix technologiques qui s’y rapportent. Cette contribution propose de s’attarder sur le cas de la gouvernance socio technique de la gestion des déchets hautement radioactifs depuis le « tournant participatif » opéré dans les années 90 en France et en Belgique. Il s’agit de poser un regard critique sur l’apparition d’un nouveau mode de gouvernance plus participatif (au travers de l’inclusion de nouveaux acteurs) et ses conséquences. Dans quelle mesure ceux-ci redéfinissent-ils les positionnements du monde scientifique au sein du processus décisionnel ? Comment le monde scientifique reçoit-il les critiques qui lui sont adressées ? Plutôt que des tendances globales, cette contestation témoigne le plus souvent d’une mosaïque d’activités critiques dynamiques, concurrentes ou complémentaires dont les effets semblent faire vaciller — ou à tout le moins mettre sous tension — l’organisation, les routines et les institutions des sociétés modernes (Delvenne 2011). Cette mosaïque reflète le dynamisme des acteurs sociaux qui propagent leurs agendas et défendent leurs intérêts à travers la négociation de concessions, l’enchevêtrement de décisions et la cristallisation de rapports de force. En d’autres termes, les avancées d’un projet comme la gestion des déchets nucléaires ne sont pas la progression inéluctable d’un processus uniformément accepté par toutes les tendances de la société. En réalité, il existe une multitude d’acteurs qui influencent sans cesse la nature de ses contours. Ces acteurs sociaux bénéficient d’espaces politiques et institutionnels divers pour exprimer leurs préférences et tenter de transformer durablement les critiques qu’ils formulent en actions politiques qui trouvent un écho plus large au sein de la société. [less ▲]

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See detailElectric current crowding in nanostructured conductors
Silhanek, Alejandro ULg

Conference (2015, May 24)

When current stream lines are forced to depart from their rectilinear trajectory due to the presence of an obstacle, they conglomerate at the sharp bends encountered on their paths. The consequent current ... [more ▼]

When current stream lines are forced to depart from their rectilinear trajectory due to the presence of an obstacle, they conglomerate at the sharp bends encountered on their paths. The consequent current crowding is present in normal metals as well as in superconductors and has been, since long ago, identified as a key player in electromigration phenomena leading to failure in integrated circuit interconnects while might also be at the origin of local ablation in planar plasmonic structures. More recently, current crowding has been recognized as an important factor limiting the performance of superconducting single-photon detectors, leading to flux quanta motion rectification, or being a source of unwanted ratchet signal and depletion of surface barriers for magnetic flux penetration. In this talk, we will also show that in nanostructured superconductors at low temperatures, current crowding can trigger abrupt flux avalanches developing well defined geometrical patterns. Our experimental findings are backed up to the finest details, by simulations based on a phenomenological thermomagnetic model which, in turn, can be used to predict such complex structures and, given its reliability, allows one to estimate physical variables of more difficult experimental access, such as the local values of temperature and electric field. [less ▲]

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See detailDo large scale restoration projects reduce within-species traits variability?
Harzé, Mélanie ULg; Monty, Arnaud ULg; Mahy, Grégory ULg

Conference (2015, May 23)

Dry calcareous grasslands represent local biodiversity hotspots of European temperate regions. They have suffered intensive fragmentations due to due to the abandonment of traditional agropastoral systems ... [more ▼]

Dry calcareous grasslands represent local biodiversity hotspots of European temperate regions. They have suffered intensive fragmentations due to due to the abandonment of traditional agropastoral systems and the resulting encroachment, reforestation, urbanization or transformation into arable lands. In order to preserve and enhance their ecological value, a series of ecological restoration projects have been implemented throughout Europe (LIFE+). As habitats restoration costs can be prohibitive, actions should demonstrate their success. In the face of environmental changes, restored populations should possess attributes necessary for adaptive evolutionary changes allowing them to persist over the long term. Intra-population functional variability expresses the range of possible trait values of a species living in a heterogeneous environment. It results notably from genetic diversity and phenotypic plasticity and enables species survival, growth and reproduction under various environmental conditions. In Belgium, three European LIFE projects have taken place between 2000 and 2009, restoring more than 400 hectares of calcareous grasslands. Restorations have mainly been evaluated in terms of plant species diversity and community composition. Though it is expected to be of crucial importance for species evolutionary potential, the restoration of the entire range of environmental heterogeneity and the resulting intra-population functional variability of restored population have so far not been assessed. We compared the intra-population variability of functional traits (specific leaf area (SLA) and maximum vegetative height) of 10 restored and 10 reference populations of Potentilla neumanniana (30 individuals per populations). We characterized abiotic and biotic conditions by measuring soil depth, sun exposure, bare ground cover and mean vegetation height around each sampled individual. Our main results showed that the range of within-species functional variability was restored in our study area. We will conclude with implications for the evolutionary potential of restored populations and for future ecological restoration projects. [less ▲]

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See detailMake the ureter your friend
Bonnet, Pierre ULg

Conference (2015, May 22)

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See detailEffect of inulin and wheat bran in the creep feed of neonatal piglets
Li, Bing ULg; Leblois, Julie ULg; Bindelle, Jérôme ULg et al

Conference (2015, May 22)

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See detailModulatory effects of Ruthenium (II)-based complexes on oxidative stress induced by activated HL60 cells and Neutrophils
Mouithys-Mickalad, Ange ULg; Collienne, Simon ULg; Franck, Thierry ULg et al

Conference (2015, May 22)

There is a growing interest on the use of metal-based chemotherapeutic agents to fight different types of cancers [1]. The most used family of the organometallic compounds is platinum derivatives whose ... [more ▼]

There is a growing interest on the use of metal-based chemotherapeutic agents to fight different types of cancers [1]. The most used family of the organometallic compounds is platinum derivatives whose Cisplatin (CisPt) is the lead compound used for the treatment of various cancers including lung, testis, gastric, breast, etc. Nevertheless, beside its recognized therapeutic effects, side effects such as gastric toxicity and acute kidney failure were observed during the treatment, limiting its clinical use. Other compounds are currently studied and among them, Ruthenium (Ru) complexes have gained more importance for their less toxicity and lower aggressive effect on healthy tissues than CisPt. Ru-complexes are also more resorbed and excreted [2]. Numerous studies focused on the mechanisms of action of Ruthenium compounds to fight cancer, including antioxidant or pro-oxidant activity. During inflammation, activation and infiltration of neutrophils contribute to oxidant stress playing a crucial role in tumor development. Likewise, the degranulation of neutrophil causes the release of myeloperoxidase (MPO) which reacts with H2O2 to catalyze redox reactions. A therapeutic target to control inflammation is the modulation of oxidant enzymes and cells involved in radical species production and redox reactions. Because Ruthenium compounds can easily enter into cancer cells, a series of Ru(II)-complexes newly synthesized were used for this purpose. They were first tested for their radical scavenging activities using ABTS and 1,1-diphenyl-2-picrylhydrazyl (DPPH) assays. Amongst them, compound 1 (LD0436) and compound 2 (LD04037) were then studied for their ability to modulate the reactive oxygen species (ROS) production by inflammatory cells like human promyelocytic leukemia cell line (HL 60) and neutrophils (PMN) using fluorescence, chemiluminescence (CL) and electron spin resonance ESR techniques. The toxicity of those Ru-complexes against HL-60 and neutrophils was checked using Trypan blue exclusion assay. Altogether, CL and ESR findings indicate that both complexes 1 (LD0436) and 2 (LD0437) exhibit a dose-dependent inhibitory activity compared to CisPt, gallic acid, curcumin and quercetin, which were taken as reference molecules in the different systems investigated. Similarly, the tested complexes also display an antioxidant profile on the substrate oxidation catalyzed by peroxidase such as MPO mainly involved in acute and chronic inflammatory situations. 1: (RuCl(p-Cymen)(S2C.IDip)]+(PF6)-], 2: (RuCl(p-Cymen)(S2C.Icy)]+(PF6)-] References: 1. Ceresa C, Brawin A, Cavaletti G, Trinidad A et al., (2014) Current Medicinal Chemistry 20(21), 2237-2265. 2. Liu, Y, Zhang X, Zhang R, et al., (2011) European Journal of Inorganic Chemistry. 1974-1980. [less ▲]

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See detailExploration de facteurs cognitifs et thymiques en lien avec les symptômes psychotiques : Analyses en clusters.
Laloyaux, Julien ULg; Laroi, Frank ULg; Nuyens, Filip et al

Conference (2015, May 22)

Introduction Il est maintenant reconnu qu’il existe différentes trajectoires possibles au développement et au maintien des symptômes psychotiques tels que les hallucinations et les idées délirantes. Ces ... [more ▼]

Introduction Il est maintenant reconnu qu’il existe différentes trajectoires possibles au développement et au maintien des symptômes psychotiques tels que les hallucinations et les idées délirantes. Ces phénomènes sont également en lien avec différents mécanismes cognitifs (e.g. style d’encodage, impulsivité) et facteurs thymiques (e.g. anxiété, dépression). Cependant, le poids de ces facteurs peut certainement varier en fonction des différentes trajectoires. Objectifs L’objectif de cette étude est d’explorer l’impact de différents facteurs cognitifs et thymiques sur les symptômes psychotiques dans un large échantillon issu de la population normale afin d’essayer d’en faire ressortir des profils différents avec l’aide d’analyses en clusters. Les mesures suivantes ont été incluses : Launay-Slade Hallucinations Scale, Schizotypal Personality Questionnaire-Brief, Peters et al. Delusions Inventory, UPPS Impulsive Behavior Scale, Beck Depression Inventory, State-Trait Anxiety Inventory (trait). [less ▲]

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See detailBifurcation Analysis of Large-Scale Dynamical Systems Using the Harmonic Balance Method
Detroux, Thibaut ULg; Renson, Ludovic ULg; Masset, Luc ULg et al

Conference (2015, May 22)

The harmonic balance (HB) method has been widely used in the past few years, as a numerical tool for the study of nonlinear industrial models. However, in its classical formulation the HB method is ... [more ▼]

The harmonic balance (HB) method has been widely used in the past few years, as a numerical tool for the study of nonlinear industrial models. However, in its classical formulation the HB method is limited to the approximation of periodic solutions. The present paper proposes to extend the method to the detection and tracking of codimension-1 bifurcations in the system parameters space. As an application, the frequency response of a spacecraft and its bifurcations are studied, together with two nonlinear phenomena, namely quasiperiodic oscillations and detached resonance curves. [less ▲]

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See detailAlain Robbe-Grillet face à l'entretien journalistique : paradoxes
Lorent, Fanny ULg

Conference (2015, May 22)

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See detailQuels profils caractérisés par l'humeur, l'activation comportementale et les stratégies de régulation émotionnelle pouvons-nous identifier dans une population adulte ?
Wagener, Aurélie ULg

Conference (2015, May 22)

The behavioural model of depression put forward that the level of activities in depressed patients decreases which maintains their low mood. Depressed patients are also known to use non-adaptive cognitive ... [more ▼]

The behavioural model of depression put forward that the level of activities in depressed patients decreases which maintains their low mood. Depressed patients are also known to use non-adaptive cognitive coping strategies (e.g. rumination, catastrophizing). Previous research underlined that cognitive coping strategies predict the level of activation (non-adaptive cognitive coping strategies predict a low level of activation). According to the dimensional approach of psychopathology, we hypothesised that sub-groups of depressed and non-depressed adults could be identified depending on their level of activation and the kind of cognitive coping strategies they use. In order to test this hypothesis, we investigated the relationships between the level of activation, the cognitive coping strategies, anxiety and depression with a cluster-analysis approach. 762 adults (530 women, 232 men; mean age= 31.54, SD= 12.08) completed an online survey assessing the above-mentioned variables with self-reports measures (BADS-SF, CERQ, BDI-II, STAI-Y B). Results identified four clusters that differed according to the level of activation, the cognitive coping strategies, the anxiety and the depression. For instance, one of the four classes highlighted that non-active depressed adults used catastrophizing and rumination contrary to another classes of active non-depressed ones. These results, providing interesting guidelines for psychological interventions, will be discussed further during the congress. [less ▲]

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See detailInvestigation of the consistency of the recent CH4 increase derived from NDACC-FTIR, ACE-FTS and GEOS-Chem
Bader, Whitney ULg; Conway, Stephanie; Strong, Kim et al

Conference (2015, May 21)

We present an update on the status of the recent methane increase study based on six FTIR ground-based sites, ACE-FTS satellite occultations and GEOS-Chem simulation.

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See detailAnatomy of the pelvis re-designed
Bonnet, Pierre ULg

Conference (2015, May 21)

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See detailAssessing employees propensity to engage in OCB: incremental validity of SJT beyond personality.
Lothe, Benoit ULg; Hansez, Isabelle ULg; Scius, Anthony et al

Conference (2015, May 21)

This study presents the validation results of a SJT developed in collaboration with a Belgian french speaking mutual insurance company for the assessment of employees OCB. The purpose is to provide ... [more ▼]

This study presents the validation results of a SJT developed in collaboration with a Belgian french speaking mutual insurance company for the assessment of employees OCB. The purpose is to provide empirical evidence concerning the validity of using the SJT by examining the issues of OCB criterion validity, incremental validity beyond a personality inventory, applicant perception and SJT transparency level. The SJT was developed in-house and following relevant literature recommendations (Weekley, Ployhart & Holtz, 2006). Data were collected on 117 white-collar employees. Three other measurements were concurrently collected: OCB using Williams & Anderson (1991) self-reported scales, personality using the Gosling, Rentfrow & Swann (2003) ten item inventory (TIPI) and applicant perception using SPJS (Bauer, & al., 2001). An open-ended question was used to access the extent to which applicants are able to identify the SJT criteria. Results indicated that the SJT is a relevant predictor of OCB (r = .42; p<.001). The SJT also provides incremental explanation of the OCB criteria beyond the personality inventory (∆R² = .11; p<.001). There was in average an agreement about the acceptability of the SJT in terms of perceived procedural justice. No relationships were found between applicant ability to correctly identify the SJT criteria and SJT score or OCB self-rating. This study is to our knowledge among the first attempt to develop and validate a tool to fill the gap on how to predict employees OCB (Organ, Podsakoff & Podsakoff, 2010). Implications for the personnel selection and current limitations will be discussed. [less ▲]

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See detailLes circuits-courts en alimentation comme réponse au défi climatique
Ozer, Pierre ULg

Conference (2015, May 20)

Detailed reference viewed: 26 (2 ULg)
See detailQuelles stratégies africaines face aux émergents?
Mputu Ingole, Jean-Claude ULg

Conference (2015, May 20)

Le rapprochement entre l’Afrique et les pays émergents pose toute une série des questions. Dans cet article, nous voulons nous interroger sur la position africaine face à ces nouveaux acteurs. Le ... [more ▼]

Le rapprochement entre l’Afrique et les pays émergents pose toute une série des questions. Dans cet article, nous voulons nous interroger sur la position africaine face à ces nouveaux acteurs. Le continent africain est-il un acteur conscient des enjeux en cours avec ces nouveaux « partenaires », pour reprendre les termes de l’Union Africaine, ou comme le suggère certains auteurs, elle serait entrain de subir une fois de plus la volonté des acteurs extérieurs ? Car si l’on constate que l’ensemble des pays émergents ont mis en place des nouvelles stratégies africaines, le contraire ne paraît pas évident. Ce papier se propose donc de voir s’il existe une ou plusieurs stratégies africaines vis-à-vis des émergents et si oui, de les analyser dans le contexte d’un monde en pleine mutation avec des nouveaux enjeux. Comment l’Union Africaine fait face aux nouvelles sollicitations des Etats émergents ? Compte-t-elle en tirer profit pour sa propre affirmation comme une actrice qui compte ou bien est-elle marginalisée par les Etats africains qui chacun, en ce qui le concerne, recherche ses propres intérêts. A-t-elle mis en place des nouveaux instruments pour gérer, selon ses intérêts cet accroissement de coopération avec les pays émergents. Quels rôles jouent les organisations régionales et/ou le NEPAD dans le développement de ces nouvelles coopérations ? Car au moment où la croissance africaine est l’une des plus fortes au monde et que le nombre de ses partenaires ne cesse d’augmenter, il est dès lors question de savoir comment l’Afrique se prépare à saisir ces nouvelles opportunités pour renforcer sa présence sur le monde avec ou sans les émergents. [less ▲]

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See detailLa coopération Sud-Sud au sein des BRICS ; un nouveau paradigme d’aide au développement? Le cas du Brésil en Mozambique
Cusson, Gabrielle ULg

Conference (2015, May 20)

L’émergence et l’affirmation de nouvelles puissances dites du « Sud », dont celles des BRICS, ont donné un nouveau souffle à la coopération Sud-Sud (CSS), et ce spécialement en Afrique. Ces émergents ... [more ▼]

L’émergence et l’affirmation de nouvelles puissances dites du « Sud », dont celles des BRICS, ont donné un nouveau souffle à la coopération Sud-Sud (CSS), et ce spécialement en Afrique. Ces émergents jouissent d’une marge de manœuvre politique et économique grandissante qui leur permet de multiplier les partenariats Sud-Sud, de contribuer financièrement à la coopération au développement et d’instaurer de nouvelles structures d’institutionnalisation de CSS. La stratégie de CSS des BRICS se veut différente du modèle traditionnel de coopération Nord-Sud (CNS) ; elle s’appuie sur des principes de solidarité, offre une aide sans condition, se base sur des relations horizontales permettant des bénéfices mutuels pour les partenaires. Cependant, la CSS engagée par les BRICS n’est pas exempte de retombées politiques, diplomatiques ou commerciales à leur égard. Dans ce contexte, il est valable de se questionner à savoir si une politique de coopération au développement déployée par une puissance émergente peut être désintéressée et s’il est possible d’établir des relations d’égal à égal alors qu’elle se développe dans un cadre de rapports entre un donateur et un récepteur ? Cette présentation tentera de déterminer si le modèle de CSS soutenu par les BRICS s’inscrit dans un nouveau paradigme pour repenser l’efficacité de l’aide au développement en Afrique ou s’il reproduit la structure d’aide traditionnelle du modèle de CNS. Pour ce faire, nous étudierons le cas de la pénétration brésilienne au Mozambique, soit son implication technique et financière au développement de l’exploitation de certaines cultures à des fins de production de biocarburants. [less ▲]

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See detailStructural properties of densified GexSe1-x glasses
Yildirim, Can ULg; Micoulaut, Matthieu; Raty, Jean-Yves ULg

Conference (2015, May 20)

The evolution in structural properties of liquid and densified glassy GexSe1-x is investigated by use of First Principles Molecular Dynamics (FPMD) combined with X-ray absorption (XAS) experiments for the ... [more ▼]

The evolution in structural properties of liquid and densified glassy GexSe1-x is investigated by use of First Principles Molecular Dynamics (FPMD) combined with X-ray absorption (XAS) experiments for the glassy state. Four different compositions (x=10%, 16%, 18% and 33%) representing the flexible and stressed rigid sides of the reversibility window are the focus of the study. The target systems were studied at pressures up to ~ 11 GPa under both annealed and cold compression conditions. We examine the structure factors, pair distribution functions, bond angle distributions, coordination numbers and neighbor distributions. The results show that the real and reciprocal space properties are in very good agreement with the experimental findings. The structural evolution during densification reveals the edge sharing tetrahedra is maintained upon compression whereas Ge-Ge homopolar bonds tend to increase in number. Ge-Se-Ge bond angular distributions show a transformation from tetrahedral octahedral geometry. We discuss the effect of thermal history on structural properties during densification. [less ▲]

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See detailCritical analysis and alternative treatment of Type Ia Supernovae data
Hauret, Clémentine ULg

Conference (2015, May 20)

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See detailL’influence normative de la Chine en Amérique latine, un défi stratégique pour l’Union européenne ?
Wintgens, Sophie ULg; Dabène, Olivier

Conference (2015, May 20)

La Chine est aujourd’hui devenue un partenaire commercial incontournable, un important pourvoyeur d’investissements directs étrangers et un grand fournisseur de prêts financiers pour un nombre croissant ... [more ▼]

La Chine est aujourd’hui devenue un partenaire commercial incontournable, un important pourvoyeur d’investissements directs étrangers et un grand fournisseur de prêts financiers pour un nombre croissant de pays d’Amérique latine. L’accroissement de ses échanges économiques et commerciaux avec ce sous-continent va de pair avec l’imposition des normes économiques et politiques dont sa politique commerciale internationale est porteuse. Cet article pose dès lors la question du défi que représente cette influence normative chinoise pour la stratégie déployée par l’Union européenne envers l’Amérique latine. [less ▲]

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See detailSimulations numériques sur des solides plongés, dans un contexte X-FEM
Duboeuf, Frédéric ULg; Béchet, Eric ULg

Conference (2015, May 20)

Ce travail traite des différents enjeux pour conserver toutes les capacités des calculs par éléments finis, en s’affranchissant des maillages conformes à la géométrie. La représentation de la géométrie ... [more ▼]

Ce travail traite des différents enjeux pour conserver toutes les capacités des calculs par éléments finis, en s’affranchissant des maillages conformes à la géométrie. La représentation de la géométrie, la construction d’un espace fonctionnel adapté et l’imposition des conditions aux limites sont abordées dans le contexte de la méthode des éléments finis étendus, tout particulièrement en présence de solides plongés dans un espace de dimension supérieure. L’approche proposée permet de traiter tout type de plongement, c.-à-d. des problèmes 1, 2, et/ou 3D plongés dans des maillages 2 ou 3D. [less ▲]

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See detailChanges of macrofauna stable isotope compositions in a very inconstant seagrass detritic habitat: actual diet modification or baseline shift?
Remy, François ULg; Mascart, Thibaud ULg; Dauby, Patrick ULg et al

Conference (2015, May 20)

Decayed leaves of the Neptune grass Posidonia oceanica, detached and then exported during storms, constitute an important compartment in terms of organic matter transfer from the seagrass bed to the other ... [more ▼]

Decayed leaves of the Neptune grass Posidonia oceanica, detached and then exported during storms, constitute an important compartment in terms of organic matter transfer from the seagrass bed to the other habitats, particularly coastal habitats. These exported litter accumulations (ELA) support a diverse (more than 130 species) and abundant (up to 4900 id.m-2) vagile macrofauna (invertebrates > 500µm) assemblage which may play a key role in the degradation, enrichment and carbon transfer from P. oceanica dead material to coastal food chains. Indeed, preliminary results of vagile invertebrates gut content observations show that even if only a few of these species ingest a large proportion of P.oceanica dead leaves fragments, most of the others ingest a small but non-negligible part, suggesting a potential role of the whole community in the mechanical fragmentation of the dead leaves. ELA are very dynamic habitats with highly variable food availability, quality, and composition. Such an inconstant habitat may result in drastic modifications of the invertebrate community but also of its trophic structure and ecology. To test this hypothesis of influence of pulsed availability, quality and composition of food sources on the vagile macrofauna diet, we took seasonal samples in Calvi Bay (Corsica, 8°45’E; 42°35’N), at two sites between August 2011 and May 2012. Stable isotopes analysis (C&N) were conducted at an individual level on dominant macrofauna species and mixing and isotopic niche model packages in R were used. Bayesian inference “SIBER” package highlighted significant seasonal and spatial differences of diet at the community, specific and even intraspecific level. Data confirm the potential transfer of seagrass material to animal tissues but in various proportions depending of the species and the season. But one question remained: are these variations reflection a true diet change, or only a spatiotemporal baseline variation of the food sources isotopic composition? “SIAR” Bayesian mixing model showed that it depends on the species and that the two responses co-occur. We emphasized the need to work at the specific level but also with an adequate temporal resolution for sampling to encompass diet and baseline variability. [less ▲]

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See detailScreening for interesting elicitors to protect wheat against Zymoseptoria tritici
Le Mire, Géraldine ULg; Siah, Ali; Fauconnier, Marie-Laure ULg et al

Conference (2015, May 19)

Plants face an array of biotic and abiotic stresses in their environment, making it necessary to use various chemical inputs to maintain satisfactory yield. Today, conventional agriculture is evolving ... [more ▼]

Plants face an array of biotic and abiotic stresses in their environment, making it necessary to use various chemical inputs to maintain satisfactory yield. Today, conventional agriculture is evolving towards more sustainable practices, out of respect for human health and the environment. Elicitors are considered as promising biological control tools and draw major interest in IPM strategies. These plant-immunity triggering compounds, also called “stimulators of plant natural defenses”, induce a general and systemic resistance in the plant to various diseases. Although numerous elicitors have already been identified and some of them reached the market since the late 1970s, further investigations are still required to better understand the mode of action of these molecules in the plant and ensure a consistent efficiency under various field conditions. Few elicitors have yet been successfully tested and formulated to protect crop plants such as wheat, which is cultivated over large areas in Europe. This study focuses on the screening of ten potential elicitor products of various origins and structures to protect winter wheat against the fungal pathogen Zymoseptoria tritici. Greenhouse trials were carried out to measure the ability of the different products to reduce disease foliar symptoms (necrosis, chlorosis and pycnidia). In addition, the phytotoxicity and biocide activities of these products were evaluated under greenhouse and laboratory conditions, respectively. The corresponding results will be presented and discussed with the perspective to choose the best elicitor candidates and to undertake investigations on the signaling pathway and the influence of environmental parameters on the elicitation capacity. [less ▲]

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See detailTuta absoluta (Lepidoptera: Gelechiidae) development on wild and cultivated plant species
Bawin, Thomas ULg; Dujeu, David ULg; Fagan, Maud ULg et al

Conference (2015, May 19)

The tomato leafminer, Tuta absoluta (Lepidoptera: Gelechiidae), is a widespread invasive species damaging economically important cultivated solanaceous crop plants, including tomatoes and potatoes. Little ... [more ▼]

The tomato leafminer, Tuta absoluta (Lepidoptera: Gelechiidae), is a widespread invasive species damaging economically important cultivated solanaceous crop plants, including tomatoes and potatoes. Little is known about the ability of this microlepidoptera to encounter and develop on alternative wild and agricultural plant species. These plants could provide refuges and have to be identified for more efficient integrated management strategies. In the present study, we assessed under laboratory conditions the ability of T. absoluta to develop on such plant species referred as potential hosts in the literature, including Solanaceae, Chenopodiaceae, Convolvulaceae, Fabaceae, and Malvaceae. For each plant species, fitness tests were performed in Petri dishes by isolating single individuals with excised leaf. We found that Solanum species allowed higher larval survivability and shorter development time (from egg to adult emergency) compared to the other plants. Non-solanaceous plants were not able to sustain T. absoluta larvae. Two choice behavioral assays performed in flying tunnels revealed that adult distribution and female oviposition did not differ between Solanum species, which were preferred to other tested solanaceous plants. These results appeared to be consistent with survival rates and development times. Because larval survivability depends on the female’s oviposition choice, the hypothesis that host plant choice is influenced by plant volatile organic compounds has to be tested. Volatile organic compounds released by solanaceous plants were trapped using a dynamic collection system, and analyzed by GC-MS. Solanum volatile profiles showed similarities, and were presenting quantitative and qualitative differences with the other tested solanaceous plants, providing some explanations in the observed behavioral discrimination. Further electrophysiological and behavioral assays are required to confirm the effect of specific chemicals on the choice of the oviposition site in T. absoluta. It can be concluded that Solanum species are the more suitable hosts for T. absoluta development. Other solanaceous plant species could be opportunistically colonized with little incidence but care should be taken in these results as genetic variability in insects and plants, as well as plant physiological state, might have an impact on the pest survivability. [less ▲]

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See detailFrom the Hubble Space Telescope to Juno, unraveling the secrets of Jupiter's UV aurorae
Bonfond, Bertrand ULg

Conference (2015, May 19)

The successive generations of instruments on board the Hubble Space Telescope (HST) have revealed an increasing amount of details concerning the aurorae of Jupiter. Among the most striking results is the ... [more ▼]

The successive generations of instruments on board the Hubble Space Telescope (HST) have revealed an increasing amount of details concerning the aurorae of Jupiter. Among the most striking results is the finding that these aurorae are actually made of a multitude of components arising from a variety of processes, ranging from the local interaction of the Jovian moons with the magnetospheric plasma to solar-wind induced compression of the whole magnetosphere. In this presentation, I will review a few recent results obtained from Hubble Space Telescope observations. First, I will show how the morphology and the dynamics of the Ganymede footprint, i.e. the aurora on Jupiter created by the electromagnetic interaction between Ganymede and Jupiter, allowed us to infer the processes at play. Then, I will present results on the vertical profile of the auroral emissions and what they tell us about the acceleration of the electrons causing the auroral emissions. Furthermore, I will describe some of the short-timescale dynamics of the polar-most emissions, including their quasi-periodic nature. Finally, I will conclude with a short description of the expected outcome of the Juno mission, which will provide its first scientific results in fall 2016. [less ▲]

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Peer Reviewed
See detailEfficiency of pheromone-based formulations against phytophagous pests
Fassotte, Bérénice ULg; Vandereycken, Axel ULg; Chevalier Mendes Lopes, Thomas ULg et al

Conference (2015, May 19)

Innovative integrated pest management methods are needed to overcome market withdrawal of synthetic pesticides. Therefore, the identification of environment-friendly bio-products carrying direct or ... [more ▼]

Innovative integrated pest management methods are needed to overcome market withdrawal of synthetic pesticides. Therefore, the identification of environment-friendly bio-products carrying direct or indirect biocide activity is one promising alternative option. Our researches focus on the identification of appropriate formulations releasing volatile organic compounds that are attractant for natural enemies of insect pests. However, the elaboration of slow-release devices that ensure stable and controlled release of active volatile compounds is quite challenging. Here, we developed a formulation based on E-β-farnesene and (-)-β-caryophyllene, these two semiochemicals having strong attractive potential on aphid natural enemies including lady beetles and hoverflies. Both compounds were encapsulated together in alginate gel beads. The blend efficiency was first evaluated through laboratory assays, and then in wheat and broad bean fields, by considering the abundance and diversity of aphids and their natural enemies. [less ▲]

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See detailApproche contingente du design du système d’information comptable dans les PMI tunisiennes
Ghorbel, Jihene ULg

Conference (2015, May 19)

Malgré les recherches qui sont de plus en plus nombreuses sur le système d’information comptable dans les PME, les résultats trouvés sont mitigés et contradictoires. Ainsi, nous essayons à travers ce ... [more ▼]

Malgré les recherches qui sont de plus en plus nombreuses sur le système d’information comptable dans les PME, les résultats trouvés sont mitigés et contradictoires. Ainsi, nous essayons à travers ce travail de contribuer au débat relatif du design du système d’information comptable dans les PMI des pays en voie de développement comme la Tunisie. Dans une optique comptable et face aux défis auxquels se trouvent confrontées les entreprises et pour légitimer leur compétitivité et leur crédibilité, nous nous intéressons à une série de facteurs structurels et comportementaux susceptibles de mieux cerner le design du système d’information comptable. En recourant aux méthodes des équations structurelles, cette recherche révèle que le design du système d’information comptable auprès de 221 PMI est influencé par plusieurs facteurs contextuels. [less ▲]

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Peer Reviewed
See detailPrésentation de cas pratique - atelier n°2 « Outils et méthodes de formation : quels outils (EAD, MOOC, partage social, manuels...) et quelles méthodes (enseignement mixte, classe inversée, résolution de problèmes, travaux en groupe...) face à des groupes de tailles très variables ? Comment former avec peu de moyens (financiers, humains, matériels) ? »
Pasquet, Coralie ULg

Conference (2015, May 18)

Au cours du premier quadrimestre de l’année académique 2014 - 2015, une nouvelle activité a été proposée aux 280 étudiants inscrits en 3ième année du grade de Bachelier en Médecine à ... [more ▼]

Au cours du premier quadrimestre de l’année académique 2014 - 2015, une nouvelle activité a été proposée aux 280 étudiants inscrits en 3ième année du grade de Bachelier en Médecine à l’Université de Liège, ce dans le cadre du « Module Système Nerveux ». La réalisation progressive de cette activité s'est effectuée exclusivement en ligne. [less ▲]

Detailed reference viewed: 56 (5 ULg)
See detailAging mechanisms in amorphous GeTe
Raty, Jean-Yves ULg; Zhang, Wei; Luckas, Jennifer et al

Conference (2015, May 18)

Aging phenomena are common to all amorphous structures, but of special importance in phase change materials (PCM) since it impedes the realization of multi-level memories. Different interpretations have ... [more ▼]

Aging phenomena are common to all amorphous structures, but of special importance in phase change materials (PCM) since it impedes the realization of multi-level memories. Different interpretations have been proposed, but we focus here on the structural relaxation of amorphous GeTe, chosen because it is the simplest system that is representative of the wider class of GST alloys, lying along the GeTe-Sb2Te3 composition line of the GeSbTe phase diagram. We investigate the structure of amorphous GeTe using Density Functional Theory based Molecular Dynamics, using either the standard Generalized Gradient Approximation, or more elaborate Van der Waals approximation. New insight is provided on the stability of homopolar GeGe bonds and tetrahedral Ge bonding, in relation with the resistance drift phenomenon, that is investigated experimentally using photothermal deflection spectroscopy experiments [less ▲]

Detailed reference viewed: 13 (1 ULg)
See detailDesign of new multifunctional nanocarriers for protein delivery
Parilti, Rahmet ULg; Jérôme, Christine ULg; Howdle, Steven M. et al

Conference (2015, May 18)

Polymeric nanoparticles have been extensively investigated for their biomedical applications especially as drug carriers. However, efficient encapsulation and delivery of therapeutic proteins in targeted ... [more ▼]

Polymeric nanoparticles have been extensively investigated for their biomedical applications especially as drug carriers. However, efficient encapsulation and delivery of therapeutic proteins in targeted manner still present challenges. This project aims to develop a novel one-pot strategy to obtain nanoparticles able to carry proteins in their core, as well as bearing targeting and/or imaging agents on their surface. In addition to this objective, polymerizations are carried out in supercritical carbon dioxide (scCO2), which confers environmentally benign features to the process. Dispersion polymerizations of hydrophilic monomer 2-hydroxyethyl methacrylate (HEMA) in are carried out in scCO2 in the presence of an initiator, cross-linker and CO2-philic photoclevable stabilizer. Upon exposure to UV light, the o-nitrobenzyl junctions present at the surface of the particles are cleaved, thus providing water dispersible hydrogels. Spherical monodisperse nanoparticles were successfully synthesized in scCO2 with two different conditions. Milder reaction conditions were achieved by using 2,2'-Azobis(4-methoxy-2,4-dimethyl valeronitrile (V70) as an initiator which opens up the platform for one-pot protein encapsulation in scCO2. [less ▲]

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See detailA tool for the precision synthesis of poly(ionic liquid)s in water
Cordella, Daniela ULg; Kermagoret, Anthony; Debuigne, Antoine ULg et al

Conference (2015, May 18)

In recent years, poly(ionic liquid)s (PIL)s were found to take an enabling role in important fields of polymer chemistry and material science. PILs combine the unique properties of ionic liquids with the ... [more ▼]

In recent years, poly(ionic liquid)s (PIL)s were found to take an enabling role in important fields of polymer chemistry and material science. PILs combine the unique properties of ionic liquids with the flexibility and properties of macromolecular architectures giving rise to a new family of functional polymers that opens new area of applications such as polymer electrolytes in electrochemical devices, powerful dispersants and stabilizers, absorbing membranes, precursors for carbon materials, porous polymers, etc. In this communication, we will report on the implementation of organometallic-mediated radical polymerization (OMRP) technique for the precision synthesis of unprecedented PILs (co)polymers. We will discuss how an organocobalt complex can efficiently control the growth of vinyl imidazolium chains and lead to PILs with predicted molar masses and low polydispersities under mild experimental conditions, which provide low temperatures (compared to the conventional radical polymerization techniques) and also the use of water as green polymerization medium. The huge potential of this system will be also highlighted by describing the one-pot synthesis of vinyl imidazolium-based block copolymers in heterogeneous conditions. This OMRP is unique for providing well-defined vinyl imidazolium based-copolymers opening for advanced PILs applications. [less ▲]

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See detailRelever le défi des outils « discovery » : les formations orientées vers l’usager
Decoster, Sara ULg

Conference (2015, May 18)

Orientés vers l’usager, reprenant les habitudes de la génération « google », les outils « discovery » remettent en question le postulat que c’est à l’usager d’étudier la recherche documentaire. Les ... [more ▼]

Orientés vers l’usager, reprenant les habitudes de la génération « google », les outils « discovery » remettent en question le postulat que c’est à l’usager d’étudier la recherche documentaire. Les bibliothèques sont invitées à aller vers l’utilisateur et à se réinventer autour de la notion de « service ». Dans un monde informationnel où les enjeux sont de plus en plus complexes, le service à l’usager implique plus que jamais que la bibliothèque joue le rôle d’intermédiaire entre l’information et l’usager. Si l’usager doit rester maître de l’information, la formation aux compétences informationnelles reste à l’ordre du jour. Donnant cours à l’aide d’un outil « discovery », j’ai conclu qu’il est nécessaire de sortir du cadre très technique d’une recherche documentaire centrée sur la typologie documentaire et les équations de recherche. Ces éléments n’ont pas perdu leur pertinence, mais doivent être intégrés dans une structure basée sur les tâches et compétences de l’utilisateur, à savoir, la compréhension des possibilités et des limites des divers outils, l’interprétation des références et les phases de sélection, obtention et évaluation de l’information. Le but final sera toujours de permettre à l’usager de devenir acteur de l’information et de trouver sa propre position dans le paysage documentaire. Si les outils « discovery » nous amènent à faire le passage de la technicité à une approche par compétences, ils nous permettent de concevoir des formations véritablement orientées utilisateur. Tel est le défi que je voudrais relever en restructurant mes activités d’enseignement. [less ▲]

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See detailDémocratie et populisme: quelle réalité pour quelle légitimité?
Biard, Benjamin; Debras, François ULg

Conference (2015, May 18)

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See detailClassical analogy for the deflection of flux avalanches by a metallic layer
Silhanek, Alejandro ULg

Conference (2015, May 17)

Motivated by the experimental observation of the exclusion of magnetic flux avalanches in a superconducting sample partially covered by a conducting capping layer, we have investigated the simpli fied ... [more ▼]

Motivated by the experimental observation of the exclusion of magnetic flux avalanches in a superconducting sample partially covered by a conducting capping layer, we have investigated the simpli fied case of the interaction of a magnetic charge (monopole and dipole) with a semi-in finite conducting plane. We have found that early theoretical descriptions for the damping enhancement due to the metallic sheet needed a correction at large vortex velocities where a decrease of the damping coe fficient is expected. We also demonstrate that vortex trajectories are strongly modi fied when penetrating into the area covered by the metallic sheet and may even be fully diverted from that area thus providing a qualitative explanation for the bending of the trajectories of flux avalanches. Our fi ndings may be extended to study the damping of Larkin-Ovchinnikov vortex instabilities and phase-slip lines in current driven systems. [less ▲]

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See detailWhy are flux avalanches deflected by a metallic layer?
Brisbois, Jérémy ULg

Conference (2015, May 15)

Sudden avalanches of magnetic flux bursting into a superconducting sample are deflected from their trajectories when they encounter a conductive layer deposited on top of the superconductor. Remarkably ... [more ▼]

Sudden avalanches of magnetic flux bursting into a superconducting sample are deflected from their trajectories when they encounter a conductive layer deposited on top of the superconductor. Remarkably, in some cases the flux is totally excluded from the area covered by the conductive layer. Even if this phenomenon has been known for a few years, there is currently no theoretical model describing it. Moreover, the question whether the deflection would also be observed for a single vortex entering the region covered by a metallic layer is still unanswered. In this work we use the magneto-optical imaging (MOI) technique, based on the Faraday effect, to show that a conductive layer (Cu) can repel flux avalanches triggered in an underlying superconducting film (Nb) (see figure). We present a simple classical model that accounts for the deflection of a single vortex and considers a magnetic monopole approaching a semi-infinite conductive plane. This model suggests the important role played in the avalanche deflection by electromagnetic braking, arising from the eddy currents induced by the moving vortex in the metal. Moreover, we have found a decrease of the vortex damping coefficient due to the metallic sheet at large vortex velocities, correcting early theoretical descriptions where a linear behaviour was proposed. [less ▲]

Detailed reference viewed: 6 (2 ULg)
See detailChristianisme et paideia dans l'Égypte byzatine : l'apport des papyrus scolaires grecs à contenu composite profane et chrétien (fin du IIIe-début du VIIIe s.)
Carlig, Nathan ULg

Conference (2015, May 14)

Documentée par des milliers de papyrus, restes de livres ou de documents, dont les plus anciens remontent à la fin du IIe siècle de notre ère, la christianisation de l’Égypte a profondément modifié le ... [more ▼]

Documentée par des milliers de papyrus, restes de livres ou de documents, dont les plus anciens remontent à la fin du IIe siècle de notre ère, la christianisation de l’Égypte a profondément modifié le rapport des populations à la paideia hellénique, sans pour autant se substituer à elle. L’examen du matériau, de la forme, de la mise en page, du contenu, ainsi que de la provenance des papyrus scolaires grecs à contenu composite profane et chrétien (fin IIIe – 1e moitié VIIIe s.), permettra d'illustrer cette problématique en relevant les continuités et les ruptures dans les stratégies d'enseignement par rapport à la paideia de tradition hellénique. [less ▲]

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See detailWhat makes the invasive Harmonia axyridis so successful? Six years of research in Gembloux provide additional answers
Fassotte, Bérénice ULg; Durieux, Delphine ULg; Vandereycken, Axel ULg et al

Conference (2015, May 14)

Following the introduction of the invasive species Harmonia axyridis (Pallas) in Europe, many research works were conducted on its ecological, economic and social impacts. Recently, our team has been ... [more ▼]

Following the introduction of the invasive species Harmonia axyridis (Pallas) in Europe, many research works were conducted on its ecological, economic and social impacts. Recently, our team has been involved in the characterization of the behavioral traits making this lady beetle species so successful. The main conclusions of two PhD works will be shortly presented: (1) Through a six-year inventory performed in Belgian agroecosystems, we have demonstrated that H. axyridis has become well established and was among the most abundant aphidophagous predatory species, causing a severe depression of biodiversity, even if communities of aphid predators are still quite diversified. (2) The social issues associated with the establishment of overwintering aggregations in human constructions were also carefully investigated. We have demonstrated the importance of social interactions on the establishment and cohesion of the aggregates. Finally, we have demonstrated that the deposition of a set of saturated and non-saturated hydrocarbons on the surfaces where the lady beetles were settling on, allowed their conspecifics to follow their markings and join the group. [less ▲]

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See detailAnticoherence of multiqubit symmetric states
Baguette, Dorian ULg; Bastin, Thierry ULg; Martin, John ULg

Conference (2015, May 13)

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See detailAuroral emissions at Jupiter and Saturn, at the crossroads of Astrophysics Geophysics and Plasma Physics
Grodent, Denis ULg

Conference (2015, May 13)

Auroral physics is at the intersection of more general fields of physics such as Astrophysics, Geophysics and Plasma Physics. In particular, the giant planets Jupiter and Saturn may be seen as slow ... [more ▼]

Auroral physics is at the intersection of more general fields of physics such as Astrophysics, Geophysics and Plasma Physics. In particular, the giant planets Jupiter and Saturn may be seen as slow rotating pulsars. For these two planets, there is a direct link between this pulsar-like behaviour and the auroral processes that are taking place in their atmosphere. We will take the example of Jupiter to illustrate haw the aurora is generated in the magnetosphere as a result of the volcanic activity of the moon Io. [less ▲]

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See detailJupiter's equatorward auroral features
Dumont, Maïté ULg; Grodent, Denis ULg; Radioti, Aikaterini ULg et al

Conference (2015, May 13)

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See detailOn the nature of cosmological time
Hauret, Clémentine ULg

Conference (2015, May 13)

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See detailFirst evidence of a volatile sex pheromone in Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae)
Fassotte, Bérénice ULg; Fischer, Christophe ULg; Durieux, Delphine ULg et al

Conference (2015, May 13)

To date, volatile sex pheromones have not been identified in the Coccinellidae family; yet, various studies have suggested that such semiochemicals exist. Here, we collected volatile chemicals released by ... [more ▼]

To date, volatile sex pheromones have not been identified in the Coccinellidae family; yet, various studies have suggested that such semiochemicals exist. Here, we collected volatile chemicals released by virgin females of the multicolored Asian lady beetle, Harmonia axyridis (Pallas), which were either allowed or not allowed to feed on aphids. Virgin females in the presence of aphids, exhibited “calling behavior”, which is commonly associated with the emission of a sex pheromone in several Coleoptera species. These calling females were found to release a blend of volatile compounds that is involved in the remote attraction (i.e., from a distance) of males. Gas Chromatography Mass Spectrometry (GC-MS) analyses revealed that (–)-β-caryophyllene was the major constituent of the volatile blend (ranging from 80 to 86%), with four other chemical components also being present; β-elemene, methyl-eugenol, α-humulene, and α-bulnesene. In a second set of experiments, the emission of the five constituents identified from the blend was quantified daily over a 9-day period after exposure to aphids. We found that the quantity of all five chemicals significantly increased across the experimental period. Finally, we evaluated the activity of a synthetic blend of these chemicals by performing bioassays which demonstrated the same attractive effect in males only. The results confirm that female H. axyridis produce a volatile sex pheromone. These findings have potential in the development of more specific and efficient biological pest-control management methods aimed at manipulating the behavior of this invasive lady beetle. [less ▲]

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See detailIs the natural shape of ions in the gas phase spherical ? The allegory of the cave (Plato) applied in mass spectrometry
Far, Johann ULg; Haler, Jean ULg; Kune, Christopher ULg et al

Conference (2015, May 13)

The transfer of ions from solution to gas phase is a critical step to produce « native species ». Coming from a highly solvating medium, ionic species will tend to find new equilibrium conformations in ... [more ▼]

The transfer of ions from solution to gas phase is a critical step to produce « native species ». Coming from a highly solvating medium, ionic species will tend to find new equilibrium conformations in the gas phase. The pathway to reach the thermodynamically stable conformation(s) involves crossing potential barriers according to the type of interactions involved. When these barriers are too high compared to the internal energy of the ions, it may result in a “partial memory” (as structural preservation) of the conformation in solution. In order to evaluate the effect of the solvent evaporation and of the various collision processes encountered by the ions in the mass spectrometer we based our strategy on the determination of deviations from a spherical shape, supposed to be the natural state of ions in the gas phase. [less ▲]

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See detailFirst experimental realization of an Iron Magneto-Optical Trap
Bastin, Thierry ULg; Crauwels, Justine ULg; Huet, Nicolas ULg et al

Conference (2015, May 13)

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See detailMarcello Venusti nel mondo di Perino del Vaga
Geremicca, Antonio ULg

Conference (2015, May 12)

Detailed reference viewed: 13 (1 ULg)
See detailRemote sensing of the atmospheric composition in the infrared spectral region within the Network for the Detection of Atmospheric Composition Change (NDACC) and the Total Carbon Column Observing Network (TCCON)
Notholt, J; Blumenstock, T; Deutscher, N et al

Conference (2015, May 12)

Remote sensing has been established as a powerful tool in atmospheric research. Throughout the last decades satellite and ground-based remote sensing instruments and methods have been developed to sample ... [more ▼]

Remote sensing has been established as a powerful tool in atmospheric research. Throughout the last decades satellite and ground-based remote sensing instruments and methods have been developed to sample the atmosphere from the microwave to the UV/Vis. The international ground based networks NDACC-IR and TCCON are based on solar absorption spectrometry in the infrared. Both networks consist of more than 30 observations sites around the globe, from the high Arctic through mid-latitudes and the tropics to the southern hemisphere and Antarctica. NDACC concentrates on stratospheric observations in relation to ozone chemistry, in many instances, information on the vertical distribution of the target species is determined. Measured trace gases include O3, HCl, HF, HNO3, ClONO2 and many others. In addition, the tropospheric composition is studied by measuring anthropogenic and biogenic species including HCN, OCS, H2O, CO, CH2O, C2H6, and C2H2. The aim of TCCON is to acquire accurate and precise column-averaged abundances of CO2, CH4, N2O, i.e. atmospheric trace gases which have a very small natural variability. TCCON measurements are linked to WMO calibration scales by comparisons with co-incident in situ profiles measured from aircraft or balloon. Results from both networks have been used in many studies in relation to stratospheric ozone chemistry, air-pollution, and with regard to the carbon-cycle. Long-term series are necessary for trend analysis, gaining insight into annual and longer term variability and placing into context shorter term process studies. Due to the similar observation geometry, the ground-based observations are optimally suitable for satellite and model validation and form an essential part of many satellite projects. They also play an important role in the validation of the Copernicus Atmospheric Monitoring Service. In our contribution we will give an overview on the current status of both networks, ongoing efforts to improve network coverage, precision and accuracy, and several examples of scientific highlights. [less ▲]

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See detailOn the nature of cosmological time
Hauret, Clémentine ULg

Conference (2015, May 11)

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See detailIntroduction
Cormann, Grégory ULg

Conference (2015, May 11)

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See detailPrevention of Synovial Membrane Inflammation & Cartilage Degradation by a Novel Chitosan
Henrotin, Yves ULg; Oprenyeszk, Frédéric ULg; Dubuc, Jean-Emile et al

Conference (2015, May 10)

Detailed reference viewed: 13 (1 ULg)