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See detailPhysical modeling of overtopping induced fluvial dike failure: effects of the channel flow and floodplain innundation
Rifai, Ismail; Erpicum, Sébastien ULg; Archambeau, Pierre ULg et al

Conference (2017, August)

Fluvial dikes have been constructed as flood defense structures, but their failure may lead to casualties and major damages in the protected areas. Flow overtopping is listed as the main cause of dike ... [more ▼]

Fluvial dikes have been constructed as flood defense structures, but their failure may lead to casualties and major damages in the protected areas. Flow overtopping is listed as the main cause of dike failure. An accurate assessment of the breach evolution is a prerequisite to a sound flood risk assessment and management. in contrast, the current knowledge of the physical processes involved in fluvial dike failure by overtopping remains highly fragmented. This paper presents experimental tests on the breaching of homogenous sand-dikes in a fluvial configuration, i.e. the flow is parallel to the longitudinal dike axis. Overtopping is initiated over a pilot notch at the dike crest. Experiments are performed for different inflow discharges in the main channel and under different levels of floodplain confinement. The transient evolution of the dike geometry is monitored using a laser profilometry technique. The detailed reconstruction of the breach formation and expansion provides key insights into the mechanisms involved in the failure of fluvial dikes. Results show that the breach development differs highly from experiments disregarding the flow parallel to the dike axis (i.e. frontal configuration) as in the fluvial configuration the breach develops mainly in the flow direction and the floodplain water level strongly conditions the breach horizontal and vertical extent. [less ▲]

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See detailCompte rendu des "Extras du Cifen" : année académique 2016-2017
Guillaume, Jean-François ULg; Van Hoof, Florence ULg; Mouton, Alexandre ULg et al

in Didactiques en Pratique (2017), 3

Ce compte rendu fait état de quatre activités organisées dans le cadre des "Extras du Cifen" lors de l'année académique 2016-17 : la conférence de Liana PINIAU sur la dyslexie (30/11/2016), la conférence ... [more ▼]

Ce compte rendu fait état de quatre activités organisées dans le cadre des "Extras du Cifen" lors de l'année académique 2016-17 : la conférence de Liana PINIAU sur la dyslexie (30/11/2016), la conférence d'Elisabeth BAUTIER sur le langage (9/3/2017), la conférence de Loïc GISCHER sur la prévention du harcèlement (29/03/2017), et l'atelier organisé par Alexandre Mouton sur les premiers secours (3/5/2017). [less ▲]

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See detailThermoelectric properties of heavily-doped Fe2YZ full-Heusler compounds
Lemal, Sébastien ULg; Ricci, Fabio ULg; Verstraete, Matthieu ULg et al

Poster (2017, July 31)

Fe2YZ full-Heusler compounds were recently predicted to exhibit very large thermoelectric power factors [Phys. Rev. Lett. 114, 136601 (2015)]. Combining first-principles density functional theory ... [more ▼]

Fe2YZ full-Heusler compounds were recently predicted to exhibit very large thermoelectric power factors [Phys. Rev. Lett. 114, 136601 (2015)]. Combining first-principles density functional theory calculations within a hybrid functional approach and Boltzmann semi-classical transport theory, we investigate the limits of the rigid band doping approximation, and the properties of heavily n-type doped full-Heusler Fe2YZ1-xAx compounds. Using a supercell approach and including explicit dopant impurities, we recover in some cases giant thermoelectric power factors, as previously predicted within the rigid band approximation. In others the effect on the electronic structure is very different from rigid shifts. Interestingly, we find that some systems present a magnetic instability consistent with the Stoner model, and evolve towards a ferromagnetic half-metallic ground state, with a strongly modified power factor. Our results show the promise of the heavily-doped phases of the studied Fe2YZ1-xAx compounds for Seebeck and spin-dependent Seebeck applications. [less ▲]

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See detailOccupational social and mental stimulation and cognitive decline with advancing age
Grotz, Catherine ULg; Meillon, Céline; Amieva, Hélène et al

in Age and Ageing (2017)

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See detailNatural patches in Posidonia oceanica meadows: the seasonal biogeochemical pore water characteristics of two edge types
Abadie, A; Borges, Alberto ULg; Champenois, Willy ULg et al

in Marine Biology (2017), 164:166

Seagrass meadows can be assimilated to seascape matrixes encompassing a mosaic of natural and anthropogenic patches. Natural patches within the Mediterranean Posidonia oceanica meadows show a structural ... [more ▼]

Seagrass meadows can be assimilated to seascape matrixes encompassing a mosaic of natural and anthropogenic patches. Natural patches within the Mediterranean Posidonia oceanica meadows show a structural particularity which consist in a duality of their edge types. One edge is eroded by bottom currents, while the adjacent meadow colonizes the bare sediments. This study aims to study the dynamics of these two edges through the investigation of the biogeochemistry (pH, total alkalinity, dissolved inorganic carbon, CO2, CH4, N2O, H2S, dissolved inorganic nitrogen, PO4 3−) within vegetated and unvegetated sediments. These observations are compared with the adjacent meadow to have a better understanding of the colonization processes. Our results reveal that the P. oceanica matrix shows differences from the vegetated edges of sand patches, especially with regard to nutrient availability, which is generally more important at the colonized edge (dissolved inorganic nitrogen up to 65.39 μM in June). A clear disparity also occurs between the eroded and colonized edge with both a seasonal and bathymetrical variation of leaf biomass with higher disparities at 10 m in June (colonized edge 1415 gDW m−2; eroded edge 1133 gDW m−2). Themost important contrasts during this study were assessed in June, suggesting that the warm period of the year is more suitable for sampling to highlight disparate characteristics in temperate seagrass meadows. These findings put into light the potential importance of biogeochemical processes in the dynamics of natural patch edges. We hypothesize that they may influence the structural dynamics of P. oceanica seascapes. [less ▲]

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See detailIntraspecific variation of Zn hyperaccumulation in Arabidopsis halleri populations
Schvartzman Echenique, Maria Sol ULg; Corso, Massimiliano; Fataftah, Nazeer ULg et al

Conference (2017, July 19)

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See detailA Novel Accelerometer-Based Method for Stride Length Estimation
Boutaayamou, Mohamed ULg; Schwartz, Cédric ULg; Denoël, Vincent ULg et al

Poster (2017, July 14)

We demonstrate the feasibility of accurately and precisely estimating the left/right average stride length from measured heel/toe accelerations in the gait of healthy, old adults. Our approach relies on ... [more ▼]

We demonstrate the feasibility of accurately and precisely estimating the left/right average stride length from measured heel/toe accelerations in the gait of healthy, old adults. Our approach relies on (1) a novel method that uses only accelerometer data without the need of additional data from, e.g., gyroscopes and/or magnetometers, and on (2) the validation of the results using reference 3D optoelectronic system data. [less ▲]

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See detailNon-pathological aging of the executive functions: influence of the Val108/158Met nucleotide polymorphism of the COMT gene
Gilsoul, Jessica ULg; Manard, Marine ULg; Collette, Fabienne ULg

Poster (2017, July 13)

Objectives. The aim of the study is to investigate the influence of the COMT Val108/158Met nucleotide polymorphism, associated with dopaminergic regulation, on executive functions in normal aging. Indeed ... [more ▼]

Objectives. The aim of the study is to investigate the influence of the COMT Val108/158Met nucleotide polymorphism, associated with dopaminergic regulation, on executive functions in normal aging. Indeed, according to the Dual-State Theory, Val/Val polymorphism of the COMT gene would favor better flexibility abilities, whereas Met/Met carriers would favor better stability abilities. These genotypic effects should be magnified in older people, as a decrease in cognitive resources increases the influence of individual genetic differences on cognitive performance. Method. We assessed the executive processes of inhibition, shifting, and updating – thanks to many different tasks in groups of young (n = 55) and aged participants (n = 45) carrying one of the three polymorphism of the COMT gene (Val/Val, Val/Met, Met/Met). T-tests between our two groups (Young versus Aged) but also a 6 (Group: Young-Met/Met, Young-Val/Met, Young- Val/Val, Old-Met/Met, Old-Val/Met, and Old-Val/Val) X 3 (Executive functioning: Inhibition, Shifting, and Updating) repeated measure ANOVA with Executive functioning as within-subject factor (p < .05) were carried out. Results. Young and old participants significantly differed on the three executive functions. The comparison of genotypic groups showed no significant differences in young or older participants respectively. Interestingly, the Old-Val/Val group showed a lower performance than the young one on inhibition tasks. Conclusion. As expected, we found an age effect on all the executive functions. The significant difference between the Young-Val/Val and the Old-Val/Val groups on inhibition suggests an age-related decrease in abilities requiring a stability component in individuals possessing a less favoring genotype for this component. [less ▲]

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See detailInfluence of environmental conditions on trophic niche partitioning among sea stars assemblages
Le Bourg, Baptiste ULg; Blanchard, Alice; Danis, Bruno et al

Conference (2017, July 10)

The Southern Ocean undergoes intense and contrasted impacts linked to climate change. The Western Antarctic Peninsula is one of the most rapidly warming regions of the world (Meredith and King, 2005 ... [more ▼]

The Southern Ocean undergoes intense and contrasted impacts linked to climate change. The Western Antarctic Peninsula is one of the most rapidly warming regions of the world (Meredith and King, 2005), resulting in sharp sea ice cover decrease (Parkinson and Cavalieri, 2012). In contrast, surface temperature and sea ice cover remain stable in other regions such as the Weddell Sea. Sea stars (Echinodermata: Asteroidea) are a key group of the Southern Ocean benthos, thought to be quite resistant to seawater temperature changes (Peck et al., 2008). Other, more indirect environmental changes, might induce important shifts in food web structure and fluxes, that may affect sea stars trophic ecology. In this context, the aim of this study was to use stable isotopes ratios of C, N and S to study sea stars trophic ecology to characterise their trophic diversity and plasticity regarding food web changes. Sea stars were sampled during the austral summer in the South Georgia (sub-Antarctic) in 2011 and in the South Shetland (2006) and South Orkney Islands (2016), as well as in the Weddell Sea (2015-2016). Trophic diversity, i.e. differences of trophic ecology between sea star species, and variability, i.e. differences of trophic ecology between individuals of the same species, were investigated in each region by investigating isotopic dispersion and isotopic niche (proxy of the trophic niche) areas and overlap. Difference in niche width and overlap between the regions may be the result of different environmental conditions, including sea ice coverage and dynamics. For example, in the South Shetland, sea stars had small and poorly differentiated isotopic niches. This result indicate that they may exploit the same benthic communities relying on few common food sources such as organic matter released during sea ice melting (Isla et al., 2006) or sinking phytoplankton (Mincks et al., 2008). Whether this situation leads to competition or not depends on the resources availability. In contrast, isotopic niches were larger and better separated for sea stars from South Georgia. South Georgia is an oligotrophic environment with no sea ice (Korb et al., 2008). As available food items are more limited but, perhaps, more diversified, a higher trophic segregation may appear between species. Ultimately, this project will help delineating processes determining trophic ecology of Southern Ocean sea stars. This research was funded by the Belgian Federal Science Policy Office (BELSPO) in the framework of the vERSO and RECTO project (rectoversoprojects.be). [less ▲]

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See detailTraducción y retraducción al francés de Conversación en La Catedral
Belleflamme, Clémence ULg

Conference (2017, July 09)

La ponencia se inscribe en el marco más amplio de una investigación de doctorado dedicada a la retraducción al francés de obras literarias hispanoamericanas de la segunda mitad del siglo XX. Además de una ... [more ▼]

La ponencia se inscribe en el marco más amplio de una investigación de doctorado dedicada a la retraducción al francés de obras literarias hispanoamericanas de la segunda mitad del siglo XX. Además de una parte teórica, dedicada a la noción traductológica de retraducción, la tesis constará de un estudio de casos, los de Pedro Páramo, de Juan Rulfo, y de Conversación en La Catedral, de Mario Vargas Llosa. Ambas novelas se tradujeron por primera vez al francés unos años después de su publicación y por segunda vez a principios del siglo XXI. Se investigarán tanto las estrategias editoriales como las estrategias de traducción, que un análisis textual de índole descriptivo debería permitirme deducir de manera inductiva a partir de las diferencias lingüísticas y pragmáticas que existen entre las distintas versiones. En esta ponencia, presento los primeros resultados del análisis textual comparativo de las versiones en francés de Conversación en La Catedral y formulo las primeras hipótesis en cuanto a los motivos para retraducir. [less ▲]

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See detailScuola e esercizi scolastici nell'Egitto tolemaico-romano
Carlig, Nathan ULg

Scientific conference (2017, July 07)

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See detailVers une politique de la ville en Wallonie (Belgique) : évolution socio-économique des villes wallonnes et recommandations
Claeys, Dorian ULg; Descamps, Julien; Wilmotte, Pierre-François ULg et al

Conference (2017, July 06)

The aim of the presentation is to present the recent trajectories of the urban neighbourhoods of 12 Walloon cities. The objective is to connect these evolutions with the urban development and policies of ... [more ▼]

The aim of the presentation is to present the recent trajectories of the urban neighbourhoods of 12 Walloon cities. The objective is to connect these evolutions with the urban development and policies of Walloon cities. [less ▲]

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See detailEmergence d’une Politique de la Ville en Wallonie en regard de la vision européenne
Mercenier, Chloé ULg; Bianchet, Bruno ULg; Ruelle, Christine ULg et al

Conference (2017, July 06)

The aim of our presentation is to present some issues for Wallonia regarding to the urban strategy of European Union (European Council of Ministers and European Commission). We present these two ... [more ▼]

The aim of our presentation is to present some issues for Wallonia regarding to the urban strategy of European Union (European Council of Ministers and European Commission). We present these two strategies: the European (Urban Agenda/Pact of Amsterdam) and the Walloon strategies. We focus our communication on two regional specific issues: cooperation between municipalities ("supracommunalité") and the rehabilitation of residential and economic functions of urban neighbourhoods. [less ▲]

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See detailVers une Politique de la Ville en Wallonie : recommandation pour la mise en oeuvre d'une politique transversale et intégrée de dynamisation des quartiers urbains
Ruelle, Christine ULg; Mercenier, Chloé ULg; Bastin, Florine et al

E-print/Working paper (2017)

La note de recherche propose les principaux résultats de la recherche CPDT 2015-2016 sur la Politique de la Ville en Wallonie. Elle concerne, plus précisément, les constats et recommandations pour le ... [more ▼]

La note de recherche propose les principaux résultats de la recherche CPDT 2015-2016 sur la Politique de la Ville en Wallonie. Elle concerne, plus précisément, les constats et recommandations pour le développement des quartiers urbains selon trois grandes catégories de difficultés : le cadre de vie dégradé, le contexte social défavorable et le contexte économique défavorable. [less ▲]

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See detailUsing amino acid stable isotopes to estimate trophic position
Sturaro, Nicolas ULg

Conference (2017, July 04)

Estimating the trophic positions of animals in food webs is useful in addressing many fundamental ecological and ecotoxicological questions. These estimates are generally based on gut content and stable ... [more ▼]

Estimating the trophic positions of animals in food webs is useful in addressing many fundamental ecological and ecotoxicological questions. These estimates are generally based on gut content and stable isotope analyses, which have become essential tools for ecotoxicologists. While these tools have proven their usefulness, they involve several pitfalls that can result in large errors in the estimation of animals’ trophic positions. Relatively recently, these tools were improved with the analysis of the compound-specific amino acid nitrogen stable isotopes. The approach is based on the fact that certain amino acids (e.g., glutamic acid) exhibit metabolic isotope fractionation and others (e.g., phenylalanine) are incorporated into the tissues of consumers in a conservative manner. Indeed, amino acids of the latter category exhibit only a small change in their nitrogen isotope composition, which is similar to that found in primary producers. Therefore, the trophic position of an animal species is estimated based on a comparison of the nitrogen isotope composition of these two groups of amino acids from a single organism. This lecture will try to show the potential of the compound-specific stable isotope analysis of amino acids to illustrate food-web structure and estimate trophic positions in wild animal populations. It will summarize recent advances from field and laboratory studies and present case studies taken from the aquatic environment. In addition, this lecture will discuss the benefits, current limitations and analytical challenges related to this approach, which continues to open new research routes in many fields of ecology, including ecotoxicology. [less ▲]

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