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See detailComputerized adaptive and multi-stage testing with R
Yan, Duanli; Magis, David ULg

Conference (2016, February 19)

Computerized Adaptive Testing (CAT) has greatly improved the accuracy and efficiency of psychological testing for decades. Multistage Testing (MST) has received much of attention recently. MST is similar ... [more ▼]

Computerized Adaptive Testing (CAT) has greatly improved the accuracy and efficiency of psychological testing for decades. Multistage Testing (MST) has received much of attention recently. MST is similar to CAT such that it allows the adaptation of the difficulty of the test to the level of ability of a test taker. Specifically, in MST, items are interactively selected for each test taker, but rather than selecting individual items, groups of items are selected and the test is built in stages. Over the last decade, researchers have investigated ways for an MST to incorporate most of the advantages from CAT and linear testing, while minimize their disadvantages. These features include testing efficiency and accuracy, greater control of test content, more robust item review, as well as simplified test assembly and administration. Therefore, MST can be an effective compromise between CAT and linear testing, embedding features and benefits from both designs. Thus, MST becomes of more and more interest to researchers and practitioners as technology advances. This presentation will first provide a general overview of a multistage test (MST) design and its important concepts and processes. It will then present the latest development on CAT and MST using R, the mstR package. The presentation will also illustrate how to simulate MST administrations using mstR package, and discuss some practical issues and considerations for MST from design to applications. [less ▲]

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See detailDistribution of inorganic and organic contaminants in the intertidal surface sediments along the Hugli River Estuary, eastern part of India
Das, Krishna ULg; Sarkar, Santosh; Thomé, Jean-Pierre ULg et al

Conference (2016, February 17)

Hooghly estuary and coastal environment in north east coast of India has been strongly affected by the rapid human settlements, intensive boating and tourist activities, deforestation and ongoing ... [more ▼]

Hooghly estuary and coastal environment in north east coast of India has been strongly affected by the rapid human settlements, intensive boating and tourist activities, deforestation and ongoing agricultural and aquacultural practices. The present work investigated trace elements (TEs, T-Hg, Al, V, Cr, Fe, Mn, Cu, Zn, Co, Ni, Ca, Sr, Li, Be, P, Mo, Ag, Cd, Sn, Sb, Ba, Pb, Bi, U, As, Se) and organohalogen compounds in surface sediment (top 0-10cm) considering 8 sampling sites along the Hugli River Estuary (HRE), India. The studied organic compounds include polychlorobiphenyls (PCBs), hexachlorocyclohexane isomers (HCHs), dichlorodiphenyltrichloroethane and metabolites (DDTs) and polybromodiphenyl ethers (PBDEs). Textural analyses of the sediment reveal an overall dominance of mud. All trace elements could be detected at variable concentrations in the following descending order: Al>Fe>Ca> P>Mn> Cu> Zn> Ba >V >Cr>Sr>Ni> Li >Co >Pb>As >Se >U >Be >Sn>Bi >Ag >Mo >Cd >Sb. A synchronous enrichment of majority of the elements were observed at the site Gangasagar (~100 km south megacity Calcutta), situated at the confluence of Hugli River and Bay of Bengal, which might be attributed to cumulative impact of the physicochemical processes and multiple anthropogenic sources. It is revealed that PCBs and DDTs were the dominant compounds among the organic pollutants accounting concentrations up to 23.5 ng.g-1 and 4.4 ng.g-1 respectively at the site Babughat, adjacent to the megacity Calcutta. The results have implications for pollution in complex estuarine environment in a meso-macrotidal setup where there is significant influx of sediments carrying huge load of inorganic and organic pollutants mainly due to rapid urbanization and industrialization. [less ▲]

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See detailPsychopathologie de la ballade : Entrer en liberté
Englebert, Jérôme ULg

Scientific conference (2016, February 17)

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See detailWerner Herzog : sur le chemin des corps
Cormann, Grégory ULg; Hamers, Jérémy ULg

Scientific conference (2016, February 15)

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See detailDynamique des flux de carbone entre l'atmosphère et des écosystèmes ouest-africains: cas des forêts et savanes sous climat soudanien au Bénin
Ago, Expédit Evariste ULg

Doctoral thesis (2016)

In West Africa as elsewhere in other parts of the world, natural and anthropogenic ecosystems are the main sources for energy, building poles and livestock fodder. They probably behave like some nets ... [more ▼]

In West Africa as elsewhere in other parts of the world, natural and anthropogenic ecosystems are the main sources for energy, building poles and livestock fodder. They probably behave like some nets carbon sinks, but there are only few studies that have focused on their carbon exchanges with the atmosphere. Preserving terrestrial ecosystems has proven essential to any emissions mitigation policy of green house gases, notably CO2. This thesis focuses on the analysis of the CO2 fluxes in three contrasting types of the ecosystem under a Sudanian climate in Benin. Specifically, it was a cultivated forest, a protected forest and a cultivated savannah. Turbulent CO2 fluxes were measured by an eddy-covariance system placed above the ecosystems. The measurements were made during variable periods of 17 months (cultivated forest), 18 months (protected forest) and 29 months (cultivated savannah). The three studied sites have been equipped by the hydro-meteorological observatory AMMA-CATCH and the national project Ouémé 2025. The CO2 fluxes data were completed by some meteorological measurements and by an inventory of dominating species the three sites. Fluxes were examined on the basis of the two main seasons imposed by the cycle of West African Monsoon. The spatial (local and regional) and temporal (hour, seasonal, annual and inter-annual) scales were considered according to the sites. Water was the main factor controlling the dynamic of the terrestrial West African ecosystems. At the daily scales, the radiation was the main driving variable of the net CO2 fluxes. Besides that radiation control, a clear relationship was observed between the net CO2 fluxes and the canopy conductance. A limited impact of saturation deficit was observed, notably during the afternoon. The soil moisture was the main factor governing the ecosystem respiration. However, no clear dependency of the ecosystem respiration on the temperature was observed at hourly scale. After long dry periods, the ecosystem respiration increased immediately in response to the first significant rains. The CO2 fluxes and the characteristics of the protected forest were always higher than those of the cultivated savannah at the daily and seasonal scales. At the annual scale, while the protected forest (Bellefoungou) and cultivated savannah (Nalohou) sequestered an average of 640 ± 50 and 232 ± 27 g C m-2, respectively considering the period of the measurements, the cultivated forest was in equilibrium with 29 ± 16 g C m-2. Overall, the three studied ecosystems were more efficient during morning and wet season than during afternoon and dry season. Finally, this study revealed that the inter-annual variability of the carbon sequestration by the cultivated savannah was mainly controlled by the ecosystem respiration variability in relation to the soil water content variation. [less ▲]

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See detailBiologie, sociologie, philosophie. Le fait moral entre Durkheim et Bergson
Caeymaex, Florence ULg

Conference (2016, February 12)

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See detailTrophic plasticity of Antarctic echinoids under contrasted environmental conditions
Michel, Loïc ULg; David, Bruno; Dubois, Philippe et al

Poster (2016, February 12)

Echinoids are common members of Antarctic zoobenthos, and different groups can show important trophic diversity. As part of the ANT-XXIX/3 cruise of RV Polarstern, trophic plasticity of sea urchins was ... [more ▼]

Echinoids are common members of Antarctic zoobenthos, and different groups can show important trophic diversity. As part of the ANT-XXIX/3 cruise of RV Polarstern, trophic plasticity of sea urchins was studied in three neighbouring regions (Drake Passage, Bransfield Strait and Weddell Sea) featuring several depth-related habitats offering different trophic environments to benthic consumers. Three families with contrasting feeding habits (Cidaridae, Echinidae and Schizasteridae) were studied. Gut content examination and stable isotopes ratios of C and N suggest that each of the studied families showed a different response to variation in environmental and food conditions. Schizasteridae trophic plasticity was low, and these sea urchins were bulk sediment feeders relying on sediment-associated organic matter in all regions and/or depth-related habitats. Cidaridae consumed the most animal-derived material. Their diet varied according to the considered area, as sea urchins from Bransfield Strait relied mostly on living and/or dead animal material, while specimens from Weddell Sea fed on a mixture of dead animal material and other detritus. Echinidae also showed important trophic plasticity. They fed on various detrital items in Bransfield Strait, and selectivity of ingested material varied across depth-related habitats. In Weddell Sea, stable isotopes revealed that they mostly relied on highly 13C-enriched food items, presumably microbially-reworked benthic detritus. The differences in adaptive strategies could lead to family-specific responses of Antarctic echinoids to environmental and food-related changes. [less ▲]

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See detailThe secret life of a Mediterranean seagrass litter macrofauna community : a history of oxygen
Remy, François ULg; Michel, Loïc ULg; Sturaro, Nicolas ULg et al

Conference (2016, February 12)

Most of the foliar primary production of Posidonia oceanica, a major Mediterranean seagrass, sheds in autumn and is exported from the meadow to adjacent areas to form "Exported Macrophytodetritus ... [more ▼]

Most of the foliar primary production of Posidonia oceanica, a major Mediterranean seagrass, sheds in autumn and is exported from the meadow to adjacent areas to form "Exported Macrophytodetritus Accumulations", EMAs. These EMAs are a habitat, shelter and feeding place for an abundant and diverse community of macrofauna. Being very dynamic places and potentially playing a role of transition compartment between water column and sediment, EMAs present high variability in term of physicochemical conditions and more specifically in term of oxygen concentration. Mild to severe hypoxic periods (2 - 0.01 mL O2.L-1) can be observed in situ at different moments of the year, and this variability thus potentially play a structuring role on the macrofauna community. During this study, our main specific questions were (1) Does oxygen stratification occur inside EMAs? (2) If present, how long does it take to observe this stratification? (3) Is the macrofauna impacted and do the dominant species occupy defined positions inside the different micro-habitats? To assess the importance of this impact, an experimental study was conducted in October 2014 near the STARESO oceanographic station (Calvi, Corsica) using an original "layer-sampling" design. The experimental construction was put underwater inside an EMA for 48 hours at a depth of 8m. Samples were collected (N=8) in a 20cm thick EMA using "sealed" boxes to sample every 5cm, from the sediment, to the water column. Oxygen, nutrients and of course the litter itself (containing the macrofauna) were sampled carefully to make sure no exchange occurred between the 4 different layers. After data analysis, the assessment was clear: oxygen stratification occurred in less than 48h and oxygen level inside the layer close to the sediment experienced a fast decrease below the hypoxia threshold (2 mL O2.L-1). Diversity was highly impacted, showing a clear positive link with oxygen concentration. Macrofauna also appeared to follow this oxygen stratification but this response was very species specific. Some species didn't follow oxygen and are present in every layer and most of them were strongly positively linked to oxygen concentration. But a few (Nebalia strausi and Athanas nitescens) were strongly negatively linked to oxygen concentration and were present only in the more hypoxic layers. This experimentation thus confirmed our in situ observations. Oxygen stratification occurred quickly (< 48h) when EMAs were experiencing calm weather. This stratification observed from the water column to the sediment was very marked. Diversity and abundance of most abundant macrofauna species were drastically influenced by this stratification, showing the importance of these micro-habitats in structuring of this macrofauna community. [less ▲]

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See detailTweeting is not teaching! But...
Choffray, Jean-Marie ULg

Diverse speeche and writing (2016)

Tweeting is not teaching! But... It wouldn’t take much to make Twitter a flexible learning platform. Inclusion of videos, intelligent use of hashtags, likes and polls – which I haven’t discovered yet – ... [more ▼]

Tweeting is not teaching! But... It wouldn’t take much to make Twitter a flexible learning platform. Inclusion of videos, intelligent use of hashtags, likes and polls – which I haven’t discovered yet –, and improved editing capabilities… do provide a potentially “explosive” learning mix. Some asked for it… Below, all my tweets as of today, in one scoop! [less ▲]

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See detailThe sanctuary of Despoina at Lykosoura: a Megalopolitan creation?
Palamidis, Alaya ULg

Conference (2016, February 11)

Pausanias states that the most important Parrhasian sanctuaries were duplicated in Megalopolis in the aftermath of its creation in the 4th century B.C. A noteworthy exception is the sanctuary of Despoina ... [more ▼]

Pausanias states that the most important Parrhasian sanctuaries were duplicated in Megalopolis in the aftermath of its creation in the 4th century B.C. A noteworthy exception is the sanctuary of Despoina at Lykosoura, which was very ancient according to the author. However, the absence of epigraphical or literary evidence concerning Lykosoura and predating the synoecism and the very limited archaeological material dating to the Archaic and Classical periods suggest that it was the site of a minor cult before the synoecism. The presence of Despoina is not attested before, and it is possible that the cult of the goddess was only developed by Megalopolis, which associated to it several other Arcadian deities and gave it an ancient and local flavour, in order to assert its position as the new cult-centre of Arcadia. Similarly, the sanctuary of Demeter Eleusinia at Basilis may have only been created or developed by Megalopolis, despite its alleged antiquity. This phenomenon finds its closest parallel in the sanctuary of Andania, controlled by the city of Messene. The presence of Demeter and deities associated with her in these sanctuaries, as well as the existence of mysteries, may reflect the growing influence of the sanctuary of Eleusis during the Hellenistic period. [less ▲]

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See detailPrésentation du programme de la conférence mondiale des humanités (Liège, août 2017)
Winand, Jean ULg

Conference (2016, February 11)

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See detailComprehensive study of the thermo-reversibility of Diels-Alder based PCL polymer networks
Defize, Thomas ULg; Thomassin, Jean-Michel ULg; Alexandre, Michaël et al

in Polymer (2016), 84

Chemical crosslinking is an efficient tool to improve or impart new properties to conventional polymers. Especially, crosslinking imparts remarkable shapeememory properties to poly-ε-caprolactone (PCL ... [more ▼]

Chemical crosslinking is an efficient tool to improve or impart new properties to conventional polymers. Especially, crosslinking imparts remarkable shapeememory properties to poly-ε-caprolactone (PCL) materials. Nevertheless, the processing of networks is often tricky due to infusibility and insolubility of cross-linked chains. Therefore, the synthesis of PCL networks including thermo-reversible crosslinks based on (retro)-Diels-Alder (DA) reaction were developed to allowpreserving the melt-processing while keeping the required mechanical properties below the melting point. This paper aims at studying in depth, such thermo-dependent network formation and stability. Besides conventional swelling experi- ments, Raman spectroscopy was revealed as a powerful tool to follow the formation of the DA adduct during the crosslinking. In combination with rheological measurements, we were able to determine the most appropriate temperatures to form the network (DA crosslinking) and to process it (retro-DA re- action) without degradation of the material. [less ▲]

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See detailDe la magie au magique. Conscience, réalité-humaine et être-dans-le-monde chez Sartre (1927-1948)
Dassonneville, Gautier ULg

Doctoral thesis (2016)

This research deals with Sartre's early existential philosophy by resituating it in the field of French post-Comtian philosophy in the early twentieth century and by re-establishing an anthropological ... [more ▼]

This research deals with Sartre's early existential philosophy by resituating it in the field of French post-Comtian philosophy in the early twentieth century and by re-establishing an anthropological moment in which the issue of magic is explored in the psychological and social sciences. Following the different paths of the conceptual exchange through which the notion of magic becomes that the magical in Sartre's view, we study three poles of sartrian phenomenological ontology : intentional consciousness, human reality and being-in-the-world. The hypothesis advanced by this thesis is that the magical, according to different modes ranging from topicalization through obliteration, plays a determining role in the elaboration of existentialism whose genesis is traced here from Sartre's very first writings in 1927.  Faced with the legacy of a positivist anthropology in terms of an analytical methodology, Sartre privileges a synthetic approach and conceives consciousness in its affective and irrational aspects. Images of magical thought are called upon for rethinking openness to the world of consciousness and its relationship to itself and to Others. Returning to Sartrian anthropology, we question how consciousness can be grasped as an irreflexive and absolute spontaneity and how human reality is interpreted through its attitudes and behaviours; in particular through the way it faces its own freedom which is fundamentally and irremediably exposed to contradiction. This structure of human reality as existential project leads Sartre to reconsider being-in-the-world as based in originary dispossession through which ontology is brought back to the magical. [less ▲]

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See detailThe dynamics of inequality in Katanga, D.R.Congo. A conversation with Bourdieu
Rubbers, Benjamin ULg

Scientific conference (2016, February 10)

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See detailSéismes et glissements de terrain sous-marins en Grèce: caractérisation par les archives sédimentaires marines
Beckers, Arnaud ULg

Scientific conference (2016, February 10)

Les séismes, tsunamis et glissements de terrain sous-marins constituent un risque majeur pour les régions côtières. Prédire ces évènements reste très difficile en raison de la complexité des processus ... [more ▼]

Les séismes, tsunamis et glissements de terrain sous-marins constituent un risque majeur pour les régions côtières. Prédire ces évènements reste très difficile en raison de la complexité des processus impliqués dans leur déclenchement. L’analyse de longues séries temporelles permet d’évaluer leur fréquence et leur éventuelle cyclicité, mais des données de ce type restent rares. J'ai étudié ces processus dans le Golfe de Corinthe en Grèce, où ils constituent une menace majeure pour les populations. Notre approche a consisté en l’étude des sédiments marins de la partie ouest du Golfe via des profils sismiques, sortes d’échographie des fonds marins, et des carottes sédimentaires. Grâce à ces nouvelles données, un inventaire des grands glissements de terrain sous-marins au cours des derniers 130 000 ans a été réalisé. Par l’analyse de carottes sédimentaires, nous avons aussi identifié des périodes d’intense activité sismique au cours du dernier millénaire. Elles témoignent de l’irrégularité des grands séismes dans la région. Enfin, des failles actives localisées en mer ont pu être cartographiées pour la première fois et leur activité a été estimée. [less ▲]

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See detailDynamics of upstream movements of the European eel Anguilla anguilla in an inland area of the River Meuse over the last 20 years
Nzau Matondo, Billy ULg; Ovidio, Michaël ULg

in Environmental Biology of Fishes (2016)

The dynamics of upstream movements of the yellow eel Anguilla anguilla were investigated at Lixhe on the Belgian River Meuse in an inland fish pass regularly monitored from 1992 to 2014. Based on a ... [more ▼]

The dynamics of upstream movements of the yellow eel Anguilla anguilla were investigated at Lixhe on the Belgian River Meuse in an inland fish pass regularly monitored from 1992 to 2014. Based on a constant year-to-year sampling effort, we examined the abundance of ascending yellow eels and their body size, seasonal movement, and the associated water temperature and flow. Over the last 23 years, the number of ascending yellow eels has declined at an average 4.2% per year since 1992. The abundance of eels in 2014 is estimated at 4.5% of the ascending stock in 1992. We observed that some annual variations in eel abundance at Lixhe might be related to opening fish passes downstream of the study site. The results clearly demonstrated that long-term declining abundance of eels has resulted in increased sizes (mean increase, 4.1 mm per year since 1992) and temperatures triggering the upstream movement process (1.03°C per decade), with earlier dates for the last eel passages reducing the difference between temperature extremes of eel passages through the fish pass during the migration season. Eel movements occurred in spring and summer at low river discharge and were mainly triggered by high-temperature events. Eels have become larger with time because of improved feeding opportunities and more growth habitats available resulting from the long-term reduction in recruitment. This study highlights the importance of investigating long time spans for a better comprehension of the changes observed in yellow eels and for the optimization of management measures and future research. [less ▲]

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