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See detailTECTONIQUE ACTIVE ET EVOLUTION DU RELIEF STRUCTURAL DE L’AURES SEPTENTRIONAL
Benabbas, Chaouki; Draidia, Salah ULg; GRECU, Florina

Conference (2014, May 26)

La masse sédimentaire de l’Aurès septentrional (Atlas saharien oriental) a une épaisseur qui dépasse 7000 mètres. Cette masse imposante présente une série à peu près concordante du Jurassique supérieur à ... [more ▼]

La masse sédimentaire de l’Aurès septentrional (Atlas saharien oriental) a une épaisseur qui dépasse 7000 mètres. Cette masse imposante présente une série à peu près concordante du Jurassique supérieur à l’Eocène moyen, par des alternances de roches cohérentes : de calcaires et dolomies du Portlandien et du Berriasien, calcaires, grès et dolomies de l’Hauterivien, grès du Barrémien, dolomies de l’Aptien, grès de l’Albien, calcaires du Cénomanien, du Turonien, du Maastrichtien et de l’Eocène et des roches meubles; marnes cénomaniennes, santoniennes, campaniennes et éocènes. Ces alternances favorisent le développement d’un relief structural par érosion différentielle. La majorité des éléments de ce relief structural sont conformes à la structure tels que les chaînons et les dépressions orientés NE- SW et qui correspondent à des anticlinaux et des synclinaux pluri kilométriques de direction N 60° E. Par ailleurs, cette diversité est liée aussi à la complexité de l’histoire géologique (héritage morpho structural) d’une part et une évolution Plio Quaternaire très active, caractérisée essentiellement par des mouvements verticaux d’autre part. En fait, le contexte géodynamique en général et la tectonique active en particulier semble jouer un rôle essentiel dans la mise en place de ce relief structural ainsi que son évolution. Cette étude se donne comme objectifs, l’identification et la caractérisation des morpho structures qui favorisent l’évolution et le démembrement de ce relief, jeune et vigoureux. [less ▲]

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See detailEstimating Antarctic ice sheet surface mass balance contribution to future sea level rise using the regional atmospheric climate model MAR
Agosta, Cécile ULg; Fettweis, Xavier ULg; Gallée, Hubert

Conference (2014, May 26)

The Antarctic ice-sheet surface mass balance (SMB) is a significant contribution to sea level changes which may mitigate the rise in sea level in a warmer climate, but this term is still poorly known. The ... [more ▼]

The Antarctic ice-sheet surface mass balance (SMB) is a significant contribution to sea level changes which may mitigate the rise in sea level in a warmer climate, but this term is still poorly known. The Antarctic SMB cannot be directly deduced from global climate models (GCMs) because of their too low resolution (~100 km) and their unadapted physic over cold and snow-covered areas. That is why the use of a regional climate models (RCM) specifically developed for polar regions is particularly relevant. We present here new estimations of the Antarctic SMB changes for the 20th and the 21st century at 40 km of resolution with the MAR (Modèle Atmosphérique Régional) RCM. Recent studies showed that large scale forcing from GCMs was the main source of uncertainty for RCM-deduced SMB, thus we first present a carefully analysis of the CMIP5 GCMs (used in the AR5 IPCC report) compared to the ERA-Interim reanalysis over the Antarctic region, from which we could select the less biased large scale forcing for MAR. We thus show the Antarctic SMB evolution as modeled with MAR forced by ACCESS1-3 for RCP 4.5 and 8.5 greenhouse gaz scenarios. We evaluate our outputs by comparing MAR forced by ACCESS1-3 and ERA-Interim for the 1980-2000 period to more than 2700 quality-controlled observations and to surface meteorological data from the READER database. We then give SMB changes estimations for the 21st century together with an analysis of uncertainties coming from the MAR model, the GCM forcing and the greenhouse gaz scenarios. [less ▲]

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See detailAn innovative lens surface functionalization to control Posterior Capsular Opacification
Huang, Yi-Shiang ULg

Poster (2014, May 26)

Cataract is the opacity of the lens, causing impairment of vision or even blindness and the surgery is still the only available treatment today. The intraocular lens (IOL) is a polymer implant designed to ... [more ▼]

Cataract is the opacity of the lens, causing impairment of vision or even blindness and the surgery is still the only available treatment today. The intraocular lens (IOL) is a polymer implant designed to replace the natural lens in the cataract surgery. However, the bio-inert materials could not satisfy the unmet need in the secondary cataract control. Posterior capsular opacification (PCO, or Secondary Cataract), characterized by a thick and cloudy layer of lens epithelial cells (LECs), is the most common postoperative complication. For the present study, a bioactive molecule is immobilized onto the conventional acrylic hydrophilic polymer pHEMA (Poly(2-hydroxyethyl methacrylate)) using oxygen plasma treatment followed by dip-coating deposition. The RGD peptide sequence, being well-known for its ability to promote cellular attachment by binding to integrin receptors, is designed to stimulate the adhesion of LECs on the IOL. The data have shown the peptide immobilized biomaterial not only exhibits similar optical and physical properties, but also reveals enhanced bio-logical properties in cell adhesion and cell morphology maintenance. By means of surface functionalization of IOL to stimulate LECs adhesion, the secondary cataract could be controlled. [less ▲]

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See detailIn search of a physiological role for thiamine triphosphate and the 25-kDa thiamine triphosphatase
Bettendorff, Lucien ULg; Lakaye, Bernard ULg; Kohn, Grégory ULg et al

Conference (2014, May 25)

In search of a physiological role for thiamine triphosphate and the 25-kDa thiamine triphosphatase L. BETTENDORFF, B. LAKAYE, G. KOHN AND P. WINS GIGA-Neurosciences, University of Liège, 4000-Liège ... [more ▼]

In search of a physiological role for thiamine triphosphate and the 25-kDa thiamine triphosphatase L. BETTENDORFF, B. LAKAYE, G. KOHN AND P. WINS GIGA-Neurosciences, University of Liège, 4000-Liège, Belgium Thiamine triphosphate (ThTP) was discovered over 60 years ago. Although it is present in most organisms from bacteria to mammals, its possible biological functions remain unclear. In contrast to thiamine diphosphate (ThDP), it is not a coenzyme. In E. coli cells, ThTP is transiently produced in response to amino acid starvation, while in mammalian cells, it is constitutively produced at a low rate. In some animal tissues, ThTP was able to phosphorylate proteins and activate a high-conductance anion channel in vitro. These observations raised the possibility of ThTP being part of a still uncharacterized cellular signaling pathway. Though it was long thought that ThTP is synthesized by a specific ThDP:ATP phosphotransferase, more recent studies indicate that two main mechanisms are involved: (1) in the cytosol adenylate kinase 1 can catalyze ThTP production from ThDP and ADP and (2) in brain mitochondria FoF1-ATP synthase can catalyze ThTP production from ThDP + Pi. The latter reaction is energized by the respiratory chain through a chemiosmotic mechanism analogous to oxidative phosphorylation. Both mechanisms are conserved from bacteria to mammals. While ThTP synthesis does not seem to require a specific enzyme, its hydrolysis in mammalian tissues is catalyzed by a very specific cytosolic 25 kDa thiamine triphosphatase (ThTPase). Because of this activity, steady-state ThTP levels are kept low in mammalian cells. ThTPase belongs to the CYTH superfamily of proteins which has representatives in all superkingdoms of life acting on tripolyphosphate and various triphosphorylated substrates. Although the whole chromosome region containing the ThTPase gene was lost in birds, orthologs of the ThTPase gene were found in all other known metazoan genomes. It seems that ThTPase activity appeared as a secondary acquisition of the CYTH proteins in the lineage leading from cnidarians to vertebrates. In particular, the Trp-53 residue of mammalian ThTPases plays a key role in substrate recognition and specificity by interacting with the thiazole part of ThTP. This residue is conserved in metazoan CYTH proteins with ThTPase activity. In order to gain insight into the physiological function(s) of the ThTP-ThTPase couple, we tried to produce a mouse invalidated in 25-kDa ThTPase. Surprisingly, we were unable to obtain any knockout animal, apparently because ThTPase seems to be required for spermatogenesis. As we previously showed that the enzyme is much more abundant in differentiated versus undifferentiated cells, we suspect that 25-kDa ThTPase might play a more general and important role during cell differentiation. Acknowledgments This work was supported by the F.R.S.-FNRS. LB and BL are respectively Research Director and Research Associate at the F.R.S.-FNRS. [less ▲]

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See detailThe physical education teacher as a physical activity promoter : Current developments
Cloes, Marc ULg

Conference (2014, May 24)

The current society needs to fight against the growing of sedentary lifestyles among the population all around the world. The school environment is identified as a pillar of the multisectorial approach ... [more ▼]

The current society needs to fight against the growing of sedentary lifestyles among the population all around the world. The school environment is identified as a pillar of the multisectorial approach that should be implemented to avoid that children who born today do not live less longer than their parents. The presentation will focus on four topics: (1) The role of school in physical activity (PA) promotion; (2) The dimensions of PA at school; (3) The action that physical education (PE) teacher can play; (4) The role of PE teacher educators in the improvement of the PE adaptation to the current needs. For one child, there are several opportunities to be physically active at school but the part of the school in youth PA is not well documented. Since recently, the only strong evidence of the effectiveness of interventions aiming to promote PA in youth was identified in adolescents when school and family/community environments are combined. However, some reviews have now revealed that school-based PA interventions can be effective for improvements in BMI, motor performance, physical activity, knowledge … In order to design one PA promotion project at school, five dimensions should be considered: (1) Physical education; (2) Sport at school (links to the community); (3) Active transportation; (4) Life environment (recesses, spaces); (5) Physical activity in the classroom. All these dimensions should be supported by a strong school policy that considers PA as a key aspect for the youth development. It means that packages of school-based strategies need to be developed. Nevertheless, PE seems to be a central aspect emphasizing the key role of the PE teachers who should become the PA promoters in every school. Unfortunately, since few decades, PE is facing a worldwide crisis raising questions about its quality and focusing on the teaching process, the inadequate school-community co-ordination, the focus on competition performance sport and the lack of interest on basic human movement and needs. Three concepts are now influencing some changes: (1) The physical literacy; (2) The accountability, and; (3) The Quality Physical Education (QPE). This means that, in PE, a special emphasis should now be set on the acquisition by the youth of knowledge, skills and attitude that will make them physically educated persons for their whole life, with the purpose to reach concrete improvements and to respect students’ needs and motivational characteristics. PE teachers have to show what they are doing in the promotion of an active lifestyle, using sports like a tool for general aims and not as a final objective. On the field, this means that new contents and teaching strategies have to be developed. The involvement of the students and the implementation of their learning into the real life should become a priority. Collaboration with other actors of the educational community (other teachers, parents) or the local community (sport clubs, sport administrations, private sector …) should be developed. PE teachers have to take these new roles. To achieve such change, they need to be supported by the PE teacher educators who have to emphasize the new educating strategies, develop concrete material and resources, contribute to create communities of practice, provide evidence based data supporting the effectiveness of the new approaches. The presentation will propose systematic ‘give and go’ between theory and practice in order to connect researchers and physical education teachers, underlining that PE can only grow with such collaboration and development of a networking. [less ▲]

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See detailTemperature regimes and aphid density interactions differentially influence VOC emissions in Arabidopsis
Hien, Truong Thi Dieu ULg; Delory, Benjamin ULg; Vanderplanck, Maryse et al

in Arthropod-Plant Interactions (2014)

The effects of volatile emissions from plants exposed to individual abiotic and biotic stresses are well documented. However, the influence of multiple stresses on plant photosynthesis and defense ... [more ▼]

The effects of volatile emissions from plants exposed to individual abiotic and biotic stresses are well documented. However, the influence of multiple stresses on plant photosynthesis and defense responses, resulting in a variety of volatile profiles has received little attention. In this study, we investigated how temperature regimes in the presence and absence of the sucking insect Myzus persicae affected volatile organic compound emissions in Arabidopsis over three time periods (0-24 h, 24-48 h, and 48-72 h). Headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry was used to evaluate Arabidopsis volatile organic compounds. The results showed that under laboratory conditions, eight volatile classes [alcohols (mainly 2-ethyl-hexan-1-ol), ketone (6-methyl hept-5-en-2-one), esters (mainly (Z)-3-hexenyl acetate), aldehydes (mainly phenylacetaldehyde), isothiocyanates (mainly 4-methylpentyl isothiocyanate), terpenes (mainly (E,E)-α-farnesene), nitrile (5-(methylthio) pentanenitrile), and sulfide (dimethyl trisulfide)] were observed on plants exposed to stress combinations, whereas emissions of six volatile classes were observed during temperature stress treatments alone (with the exception of nitriles and sulfides). Aphid density at high temperature combinations resulted in significantly higher isothiocyanate, ester, nitrile and sulfide proportions. The results of the present study provide an insight into the effects of temperature - aphid interactions on plant volatile emissions. [less ▲]

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See detailAge de retraite et risque de démence : effet du genre et de la profession
Grotz, Catherine ULg; Letenneur, Luc; Meillon, Céline et al

Conference (2014, May 23)

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See detailL'apport de la papyrologie à l'histoire de la réception des traités hippocratiques à la période byzantine
Marganne, Marie-Hélène ULg

Scientific conference (2014, May 23)

Examen des témoignages papyrologiques de la période byzantine relatifs à Hippocrate et aux traités hippocratiques, de leur texte, de leur mise en texte et de leur contexte de production et d'utilisation ... [more ▼]

Examen des témoignages papyrologiques de la période byzantine relatifs à Hippocrate et aux traités hippocratiques, de leur texte, de leur mise en texte et de leur contexte de production et d'utilisation, en vue, non seulement de définir leur spécificité par rapport aux autres papyrus grecs médicaux et aux papyrus iatro-magiques de la même époque, mais aussi d’y déceler des traces éventuelles de copie ou d’utilisation en contexte chrétien. [less ▲]

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See detailCréativité et rétablissement
Vandeninden, Elise ULg

Conference (2014, May 23)

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See detailImpact of micro-physics and macro-physics on the seismic properties of main-sequence B-type stars
Salmon, Sébastien ULg

Doctoral thesis (2014)

L’étude des pulsations stellaires, tout comme les ondes sismiques sur Terre, nous donne une méthode puissante afin de découvrir l’intérieur des étoiles. Cette discipline scientifique est aussi connue sous ... [more ▼]

L’étude des pulsations stellaires, tout comme les ondes sismiques sur Terre, nous donne une méthode puissante afin de découvrir l’intérieur des étoiles. Cette discipline scientifique est aussi connue sous le nom d’astérosismologie. Grâce aux missions spatiales CoRoT et Kepler, l’astérosismologie est entrée depuis dans une période faste. Par ailleurs, une frac- tion significative des étoiles présente des pulsations, ce qui nous permet de sonder leur intérieur pour la plupart de leurs stades d’évolution. Cette thèse se concentre sur les étoiles de type B de la séquence principale. Via l’inter- action de leurs vents stellaires avec leur milieu environnant et la production de nouveaux éléments chimiques en leurs intérieurs, elles contribuent aux processus dynamiques et d’enrichissement chimique du milieu interstellaire. Heureusement, deux types de pulsa- tion stellaire affectent ces étoiles: d’une part les pulsations dites de type β Cephei et d’autre part celles de type SPB. La nature de ces pulsations est sensible aux processus physiques internes de ces étoiles. Ainsi, l’observation de ces pulsations nous offre de sonder ces différents processus. Dans cette thèse, nous étudions tout particulièrement la sensibilité de ces étoiles aux opacités ra- diatives, et nous appuyant sur ces résultats, contraignons l’opacité radiative des éléments du groupe du fer à l’aide des étoiles pulsantes repérées dans les Nuages de Magellan. Dans une seconde étape, nous évaluons la possibilité de contraindre la nature du mélan- ge (diffusif ou overshooting instantané) à l’aide de la modélisation des β Cephei par l’ap- proche directe. Nous testons également les facteurs influençant la détermination de l’exten- sion de la zone mélangée. Enfin, nous proposons un scénario explicatif de la récente découverte d’une nouvelle classe d’étoiles variables dans un amas stellaire connu pour comporter de nombreuses étoiles en rotation rapide. [less ▲]

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See detailGénétique des adénomes hypophysaires
Beckers, Albert ULg

Scientific conference (2014, May 23)

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See detailEntre imprimerie et édition : aspects de la production du livre en région liégeoise (XIXe-XXIe siècles)
Durand, Pascal ULg; Habrand, Tanguy ULg

Scientific conference (2014, May 23)

Après une introduction sur l'imprimerie liégeoise à la fin de l'ancien régime et sur les effets durables de la contrefaçon industrielle, puis de son abrogation en 1852-1854, l'exposé a proposé un tableau ... [more ▼]

Après une introduction sur l'imprimerie liégeoise à la fin de l'ancien régime et sur les effets durables de la contrefaçon industrielle, puis de son abrogation en 1852-1854, l'exposé a proposé un tableau construit sous différents paramètres (historiques, en termes de régime de production et en termes de genres pratiqués) des principaux imprimeurs-éditeurs et éditeurs en région liégeoise du XIXe au XXIe siècle : édition religieuse et scolaire (Dessain), bande dessinée et livre pour la jeunesse (Chagor, Marabout, Hemma) ; architecture et sciences humaines (Mardaga), poésie (L'arbre à Paroles, L'Atelier de l'Agneau, Le Fram), livres d'art, de cinéma et de photographie (Yellow Now), littérature régionaliste (Dricot) et livre d'actualité (Luc Pire). [less ▲]

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See detailAllergies alimentaires : quel bilan ?
GADISSEUR, Romy ULg

Conference (2014, May 23)

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See detailDetection of non concave and non increasing multifractal spectra using wavelet leaders (Part II)
Kleyntssens, Thomas ULg; Esser, Céline ULg; Nicolay, Samuel ULg

Conference (2014, May 22)

This talk follows "Detection of non concave and non increasing multifractal spectra using wavelet leaders (Part I)" given by Céline Esser. A multifractal formalism is a numerically computable formula that ... [more ▼]

This talk follows "Detection of non concave and non increasing multifractal spectra using wavelet leaders (Part I)" given by Céline Esser. A multifractal formalism is a numerically computable formula that approximates the spectrum of singularities of a function. A new multifractal formalism based on the wavelet leaders is presented as well as a comparison with other formalisms. Its main advantages are that it allows to detect non concave and non increasing spectra. An implementation is proposed. [less ▲]

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See detailDetection of non concave and non increasing multifractal spectra using wavelet leaders (Part I)
Esser, Céline ULg; Kleyntssens, Thomas ULg; Bastin, Françoise ULg et al

Conference (2014, May 22)

Multifractal analysis is concerned with the study of very irregular signals. For such functions, the pointwise regularity may change widely from a point to another. Therefore, it is more interesting to ... [more ▼]

Multifractal analysis is concerned with the study of very irregular signals. For such functions, the pointwise regularity may change widely from a point to another. Therefore, it is more interesting to determine the spectrum of singularities of the signal, which is the Hausdor ff dimension of the set of points which have the same H ölder exponent. For real-life signals, the computation of the spectrum of singularities from its de finition is not feasible. Multifractal formalisms are used to approximate this spectrum. Currently, there exist several methods. In this talk, we present a new multifractal formalism based on the wavelet leaders of a signal which allows to detect non concave and non increasing spectra. [less ▲]

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See detailApplications des microalgues
Franck, Fabrice ULg; Remacle, Claire ULg

Conference (2014, May 22)

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