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See detailCharacterization, dynamics and trophic ecology of macrofauna associated to seagrass macrophytodetritus accumulations (Calvi Bay, Mediterranean Sea)
Remy, François ULg

Doctoral thesis (2016)

Posidonia oceanica meadows are a major coastal Mediterranean ecosystem. Although highly productive this Mediterranean marine flower plant is not much consumed by herbivore organisms. During autumnal ... [more ▼]

Posidonia oceanica meadows are a major coastal Mediterranean ecosystem. Although highly productive this Mediterranean marine flower plant is not much consumed by herbivore organisms. During autumnal senescence, most (up to 90%) of the foliar primary production of P. oceanica ends in the “detrital compartment”. These dead leaves, also called “macrophytodetritus”, begin to degrade immediately inside the meadow, but a large amount will be rapidly exported to adjacent unvegetated accumulation zones, such as bare sand patches. Associated to drift macroalgae, living detached P. oceanica shoots, micro-organisms and fine sediment, these macrophytoderitus form what we call “exported P. oceanica litter”. This exported litter is a highly dynamic habitat for a whole community of invertebrates: meiofauna (38µm < size < 500µm) and macrofauna (size ≥ 500µm) on which we focused on. This dynamic nature of exported litter could play a major structuring role in terms of abundance, diversity and trophic ecology of this vagile macrofauna community at a seasonal, annual or spatial scale, but also during stochastic, brief and very strong perturbations: resource pulses. In this context, this PhD Thesis had 7 main objectives: i. Characterize for the first time exhaustively the macrofauna community. ii. Evaluate the spatiotemporal changes occurring at two different time scales in the detritus themselves and in the macrofauna community. iii. Relating these variations with measured environmental parameters. iv. Experimentally demonstrate the stratification occurring in a stable P. oceanica litter accumulation and the impact of this stratification on environmental conditions and on the macrofauna. v. Experimentally demonstrate the impact of resource pulses on the exported P. oceanica litter macrofauna community. vi. Unravel for the first time the global P. oceanica litter macrofauna food web using gut contents examinations and stable isotopes (C and N). vii. Evaluate the spatiotemporal changes of diet preferences of this community and determine if the observed changes are really synonym of true diet changes. This PhD Thesis demonstrated that exported P. oceanica litter was mainly composed of dead P. oceanica leaves (70-80%). It followed the natural annual cycle of P. oceanica and presented a maximum abundance in autumn just after leaves senescence. Measured environmental parameters also showed important variations linked to different factors such as force and direction of the wind, litter abundance and probably temperature. The continuous presence of the vagile macrofauna community throughout the year was demonstrated as well. This community was composed of 115 species and largely dominated by arthropods (77%), followed by annelids (12%) and mollusks (7%), while other taxa were much more anecdotal. Even if diversity is quite important, only a few species dominate largely the community. Indeed, 19 species represent more than 90% of the total abundance. One species to keep in mind: Gammarella fucicola, the most typical dominant and abundant amphipod species, representing 40-50% of the total abundance. In addition to this general pattern, litter vagile macrofauna presented important seasonal and annual variations. In the case of several species, these variations could be linked to some measured environmental parameters, but we had to recognize that most species did not seem to be influenced by environmental parameters measured during this PhD. However, oxygen concentration was the most important environmental parameter, potentially influencing 7 of the 19 most dominant and abundant species. The experimentally demonstrated physico-chemical stratification occurring inside litter accumulations was strongly related to this oxygen parameter. Indeed we demonstrated that several species were distributed in the different layers of a litter accumulation according to oxygen concentration and to a lesser extent, to nutrients concentration (mostly NH4). Besides, smaller time scale sampling allowed the identification of several stormy events corresponding to the definition of resource pulses. These pulses were demonstrated to play a potentially important role on the structure of the macrofauna community, favoring importantly the detritivore species and hypoxia tolerant species. It was also demonstrated that resource pulses could induce diet switching increasing the consumption of dead P. oceanica leaves just after the events, potentially increasing the litter decomposition by the macrofauna. The trophic web described in this PhD Thesis was composed of several trophic levels, from the primary herbivore/detritivore consumer, to second order carnivore predators. Different dietary preferences were highlighted, but major information was that dead P. oceanica leaves were ingested by a majority (85%) of the sampled species. Moreover, stable isotope analysis confirmed that P. oceanica litter was assimilated by most primary consumers and this “detrital signal” could be identified to the upper trophic levels, which is an argument in favor of the importance of macrofauna as major dead P. oceanica leaves decomposers. This also highlighted their potential role in terms of organic matter transfer from the P. oceanica meadow itself to the Mediterranean coastal food webs. Seasonal variations were observed in terms of trophic niches, and SIAR mixing model confirmed that this variability was sometimes caused by real diet modifications, potentially linked to the variable availability of food sources. This PhD Thesis, combining standardized sampling at two different time scales, trophic web analysis (gut contents and stable isotopes) and original experimentation allowed us to describe a diverse and abundant macrofauna community associated to P. oceanica exported litter, its temporal variations, potential responses to resource pulses as well as the link existing between some species and measured environmental parameters. This PhD also described the food web of this community and demonstrated the importance of dead P. oceanica leaves as food source for many invertebrates composing this community. These invertebrates thus seemed to play an important role in both litter decomposition and organic matter flux from the P. oceanica meadow to the Mediterranean coastal food webs. [less ▲]

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See detailLe passé en France au XVIIe siècle. Représentations, usages et transferts des savoirs historiques
Saal, Caroline ULg

Doctoral thesis (2016)

La majeure partie des études sur le passé au XVIIe siècle se porte sur l’historiographie, sur la théorie de l’histoire et sur son écriture à cette époque. Grâce au développement de l’histoire des idées et ... [more ▼]

La majeure partie des études sur le passé au XVIIe siècle se porte sur l’historiographie, sur la théorie de l’histoire et sur son écriture à cette époque. Grâce au développement de l’histoire des idées et de l’histoire culturelle, de nouvelles approches ont émergé. Pour l’histoire moderne française, elles prennent essentiellement la forme d’études de figures souvenirs et de leur prégnance dans une culture donnée. Mais deux postulats m’ont invitée à travailler autrement, hors des pratiques historiennes et sans choisir a priori de figures-souvenirs. Le premier tient à l’acquisition des savoirs historiques. La connaissance que possède une personne sur le passé de la communauté humaine résulte d’une multitude de vecteurs et de médias, de nature et d’objectifs divers, et, plus encore, elle résulte de leur croisement. Le second postulat provient des innovations en histoire des savoirs de ces dernières années : une société ancienne repose sur un système de pensée et sur une configuration des savoirs distincte de la nôtre. Pour travailler sur les savoirs sous l’Ancien Régime, il faut appréhender l’altérité d’un ancien régime des savoirs et, plutôt que de rechercher la généalogie de disciplines, regarder à l’œuvre ces savoirs mixtes, aux nombreuses ramifications, la manière de les créer, de se les approprier et de les utiliser. Certes, Reinhart Koselleck et Kristof Pomian avaient déjà produit d’importants enseignements sur les processus. On a longtemps considéré qu’ils avaient probablement tout dit. Il fallait pourtant vérifier la percolation de ces enseignements au-delà des génies créateurs et des penseurs institués. Cette thèse étudie ces processus dans des opérations d’appropriation des savoirs historiques au sein des publics alphabétisés et la compréhension de ces savoirs en société : les pamphlets « historiés » de la Fronde, les conférences du Bureau d’Adresse de Théophraste Renaudot et des estampes ludiques – jeux de carte et jeux de l’oie historiques. Elle démontre le rôle de ces imprimés de forme brève comme lieux d’acculturation des savoirs historiques, mettant à disposition un prêt-à-penser sur le passé. S’inspirant des grilles de lecture des théories de la pensée complexe, développée entre autres par Edgar Morin, elle éclaire la pluralité des questions que se posaient les hommes de l’époque moderne sur leur passé, et les liens entre ces questions, leur lieu social d’émergence, les pratiques de la connaissance et les paradigmes culturels. [less ▲]

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See detailCritique des critiques. La crise de la légitimité des journalistes spécialisés en cinéma.
Krywicki, Boris ULg

Conference (2016, May 04)

Bien avant l'avènement d'internet, les critiques cinéma se questionnaient déjà sur la légitimité de leurs jugements. Une table ronde, appelée "Point Critique", s'est interrogée sur leur rôle, la ... [more ▼]

Bien avant l'avènement d'internet, les critiques cinéma se questionnaient déjà sur la légitimité de leurs jugements. Une table ronde, appelée "Point Critique", s'est interrogée sur leur rôle, la pertinence de leur position d'intermédiaire entre distributeurs et spectateurs. A l'ère du numérique, cette crise semble d'autant plus prégnante. Plusieurs circuits fermés de l'évaluation se sont développés sur le web. Les amateurs échangent leurs propres avis en leur sein, affranchis des interventions des critiques professionnelles. Comment la critique de la presse traditionnelle - qui cherche à convaincre le plus de public possible - gère-t-elle cette crise de la légitimité de ses auteurs ? [less ▲]

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See detailChangements climatiques : les impacts des ruminants et quels leviers d'action
Beckers, Yves ULg

Scientific conference (2016, May 02)

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

in Polar Biology (2016), 39(5), 913-923

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 detailCystatin C standardization decreases assay variation and improves assessment of glomerular filtration rate
Ebert, N; DELANAYE, Pierre ULg; Shlipak, M et al

in Clinica Chimica Acta (2016), 456

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

Diverse speeche and writing (2016)

So, that’s it! Five hundred Tweets on "The Art and Science of Investing" to show you the way, to share my most recent observations on the behavior of the markets, and to illustrate some of the key ... [more ▼]

So, that’s it! Five hundred Tweets on "The Art and Science of Investing" to show you the way, to share my most recent observations on the behavior of the markets, and to illustrate some of the key heuristics that I learned over the last twenty years. As, without any doubt, I am no Warren Buffett, feel free to disagree and develop you own “theory” of investing. Painful and solitary work... Success is at this price! And, based on what I did - and did not! - achieve, it shouldn’t be hard to do much better... That’s my wish for you! [less ▲]

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See detailPhysical activity: an unknown concept
Cloes, Marc ULg

Conference (2016, April 29)

Physical educators do not have necesseraly good representations about physical activity and sedentariness. During the presentation, participants will be involved in an interactive process aiming to ... [more ▼]

Physical educators do not have necesseraly good representations about physical activity and sedentariness. During the presentation, participants will be involved in an interactive process aiming to underline the main concepts that they should use in order to become effective agents of physical activity promotion. [less ▲]

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See detailUse of stable isotope ratios to delineate coastal benthic food web structure in Adélie Land (East Antarctica)
Michel, Loïc ULg; Dubois, Philippe; Eleaume, Marc et al

Poster (2016, April 29)

Antarctica currently undergoes strong and contrasted impacts linked with climate change. While the West Antarctic Peninsula is one of the most rapidly warming regions in the world, resulting in sea ice ... [more ▼]

Antarctica currently undergoes strong and contrasted impacts linked with climate change. While the West Antarctic Peninsula is one of the most rapidly warming regions in the world, resulting in sea ice cover decrease, in some parts of East Antarctica sea ice cover tends to increase, possibly in relation with changes in atmospheric circulation. Changes in sea ice cover are likely to influence benthic food web structure through modifications of benthic-pelagic coupling, disruption of benthic production and/or modifications of benthic community structure (i.e. resource availability for benthic consumers). Here, we studied shallow (0-20 m) benthic food web structure on the coasts of Petrels Island (Adélie Land, East Antarctica) during an event of unusually high spatial and temporal (two successive austral summers without seasonal break-up) sea ice cover. Using stable isotope ratios of C, N and S, we examined importance of several organic matter sources (benthic macroalgae, benthic biofilm, sympagic algae, suspended particulate organic matter and penguin guano) for nutrition of over 20 taxa of benthic invertebrates (sponges, sea anemones, nemerteans, sessile and mobile polychaetes, gastropods, bivalves, sipunculids, pycnogonids, amphipods, sea stars, sea urchins and sea cucumbers) spanning most present functional guilds. Our results provide insights about how Antarctic benthic consumers, which have evolved in an extremely stable environment, might adapt their feeding habits in response to sudden changes in environmental conditions and trophic resource availability. [less ▲]

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See detailCOP21 and Electrical Systems
Ernst, Damien ULg

Speech/Talk (2016)

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See detailModelling of long-term deep renovation strategies for the Belgian building stock
Ruellan, Guirec ULg

Poster (2016, April 28)

To achieve the EU energy targets for 2050, the construction sector has to perform major transformations. In Belgium, the majority of building stock is particularly old and energy inefficient. The high ... [more ▼]

To achieve the EU energy targets for 2050, the construction sector has to perform major transformations. In Belgium, the majority of building stock is particularly old and energy inefficient. The high performance of new constructions represented in the nearly zero energy buildings target is not sufficient to ensure the efficiency of the overall building sector. Therefore, it is crucial to put in place a progressive renovation policy. Despite the different renovation strategies and projects that took place in the recent year in Belgium, the overall renovation rate remains almost stable for the last ten years. This study focuses on the renovation market in Belgium and analyzes the factors that influence the evolution of the renovation rate. The objective is the identification and development of effective strategies bypass that leads to increased renovation rates in Belgium. The research methodology is based on an iterative process, based on a systematic literature review of Flemish and Walloon projects, publications and policy. These first work package will allow to identify factors influencing the renovation rate and in other hand to build a model of the existing building stock. Impacts of the influencing factors on the building stock are simulated in the fourth work package in order to propose an action plan in the last part. Three mains outcomes are expected: A model of the existing building stock in Belgium and its retrofit potential, a simulation of the effects of different strategies used to increase the renovation rate in Belgium and a theoretical action plan on strategies to increase the rate of renovation in Belgium. These results are necessary to inform and support the decision making of policy makers, municipalities and operational planning authorities across Belgium. [less ▲]

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See detailEvolution de l'enseignement par la simulation
Servotte, Jean-Christophe ULg

Conference given outside the academic context (2016)

Présentation de l'évolution de la simulation avec un focus sur la pédagogie utilisée ainsi que sur les facteurs humains et l'impact sur la qualité des soins et la sécurité des patients

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See detailDiscontinuity lines in superconducting films with predefined edge defects
Brisbois, Jérémy ULg

Conference (2016, April 27)

We present a thorough investigation by magneto-optical imaging of the magnetic flux penetration in Nb thin films with lithographically defined border indentations. We demonstrate that discontinuity lines ... [more ▼]

We present a thorough investigation by magneto-optical imaging of the magnetic flux penetration in Nb thin films with lithographically defined border indentations. We demonstrate that discontinuity lines (d-lines), caused by the abrupt bending of current streamlines around the indentations, depart from the expected parabolic trend close to the defect and depend on the shape and size of the indentation as well as on the temperature. These findings are backed up and compared with theoretical results obtained by numerical simulations and analytical calculations highlighting the key role played by demagnetization effects and the creep exponent n. In addition, we show that the presence of nearby indentations and submicrometer random roughness of the sample border can severely modify the flux front topology and dynamics. Strikingly, in contrast to what has been repeatedly predicted in the literature, we do not observe that indentations act as nucleation spots for flux avalanches, but they instead help to release the flux pressure and avoid thermomagnetic instabilities. [less ▲]

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See detailTropospheric water vapour isotopologue data (H216O, H218O and HD16O) as obtained from NDACC/FTIR solar absorption spectra
Barthlott, Sabine; Schneider, Matthias; Hase, Frank et al

in Earth System Science Data Discussions (2016)

We report on the ground-based FTIR (Fourier Transform InfraRed) tropospheric water vapour isotopologue remote sensing data that have been recently made available via the database of NDACC (Network for the ... [more ▼]

We report on the ground-based FTIR (Fourier Transform InfraRed) tropospheric water vapour isotopologue remote sensing data that have been recently made available via the database of NDACC (Network for the Detection of Atmospheric Composition Change; ftp://ftp.cpc.ncep.noaa.gov/ndacc/MUSICA/) and via doi:10.5281/zenodo.48902. Currently, data are available for 12 globally distributed stations. They have been centrally retrieved and quality filtered in the framework of the MUSICA project (MUlti-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water). We explain particularities of retrieving the water vapour isotopologue state (vertical distribution of H162O, H182O and HD16O) and reveal the need for a new meta-data template for archiving such FTIR isotopologue data. We describe the format of different data components and give recommendations for correct data usage. Data are provided as two data types. The first type is best-suited for tropospheric water vapour distribution studies disregarding different isotopologues (comparison with radiosonde data, analyses of water vapour variability and trends, etc.). The second type is needed for analysing moisture pathways by means of {H2O,delta-D}-pair distributions. [less ▲]

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See detailRéparation des bétons: principes, matériaux et techniques
Courard, Luc ULg

Scientific conference (2016, April 26)

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See detailCOP21 : le grand enfumage
Alaluf, Mateo; Bayot, Bernard; Brouyaux, Antoinette et al

Article for general public (2016)

C’est à partir de ce vendredi que l’accord sur le climat obtenu en décembre dernier est ouvert à la signature. Entre les intentions annoncées et les moyens mis en œuvre par les Etats pour les atteindre ... [more ▼]

C’est à partir de ce vendredi que l’accord sur le climat obtenu en décembre dernier est ouvert à la signature. Entre les intentions annoncées et les moyens mis en œuvre par les Etats pour les atteindre, il subsiste un gouffre. Et la réalité est inquiétante. [less ▲]

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See detailNo Evidence of Herpesvirus Infection in West Highland Terriers with Canine Idiopathic Pulmonary Fibrosis
Roels, Elodie ULg; Dourcy, Mickael ULg; Holopainen, S. et al

in Veterinary Pathology (2016)

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