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See detailPOLYMER BIODEGRADABLE MATRICES WITH ENHANCED SURFACE PROPERTIES FOR TISSUE ENGINEERING
Markvicheva, Elena; Drozdova, Maria; Demina, Tatiana et al

Poster (2015)

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See detailIn vitro degradation study of Polydioxanone (PDO) monofilaments
Sevrin, Chantal ULg; Lombart, François ULg; Kottgen, Cindy et al

Poster (2015)

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See detailCancer du sein et retour au travail
Schippers, Nathalie ULg; Van Hoof, Elke; Mairiaux, Philippe ULg

Poster (2014, December 17)

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See detailUnstudied species of Lepilemur of Northwest Madagascar
Wilmet, Leslie ULg; Beudels-Jamar, Roseline C.; Schwitzer, Christoph et al

Poster (2014, December 16)

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See detailAnxiété et dépression chez l'enfant parentifié. Mieux identifier pour mieux intervenir.
Haxhe, Stéphanie ULg; Stassart, Martine ULg; D'Amore, Salvatore ULg

Poster (2014, December 16)

La parentification reste un phénomème mal connu. Pourtant, les conséquences pour l'enfant sont à prendre au sérieux.

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See detailVariability of Jupiter’s Main Auroral Emission in Response to Magnetospheric Hot Plasma Injections
Badman, Sarah; Bonfond, Bertrand ULg; Fujimoto, Masaki et al

Poster (2014, December 16)

We present observations of Jupiter’s FUV aurora acquired by the Hubble Space Telescope during a two-week interval in January 2014. The variability of the main auroral emission was studied using ... [more ▼]

We present observations of Jupiter’s FUV aurora acquired by the Hubble Space Telescope during a two-week interval in January 2014. The variability of the main auroral emission was studied using latitudinal profiles of intensity. The main oval intensity was found to be reduced when bright patches of diffuse emission were present at lower latitudes. These low latitude emissions are interpreted as the signatures of hot plasma injections from the outer magnetosphere, a process which has previously been related to interchange between the flux tubes from the outer magnetosphere and outward-moving flux tubes loaded with iogenic plasma. The main emission was also observed to broaden and shift in latitude, and occasionally display a double peak structure. These observations are interpreted with reference to the expected changes in auroral field-aligned currents associated with the replacement of the radially-stretched, mass-loaded flux tubes in the middle magnetosphere by more dipolar flux tubes containing rarefied hot plasma. [less ▲]

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See detailBiostratigraphic and chemostratigraphic constraints of the Mbuji-Mayi Supergroup, Democratic Republic of Congo
Kabamba Baludikay, Blaise ULg; Bekker, Andrey; Baudet, Daniel et al

Poster (2014, December 16)

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See detailPhytochemical Study of Plants of Interest for Cosmetics in Mayotte
Saive, Matthew ULg; Fauconnier, Marie-Laure ULg; Danflous, Jean-Paul

Poster (2014, December 16)

This study takes place in a bigger project aiming to identify and to make an inventory of the French Pharmacopeia. Its aim is to identify plants or plant families regularly used in traditional cosmetics ... [more ▼]

This study takes place in a bigger project aiming to identify and to make an inventory of the French Pharmacopeia. Its aim is to identify plants or plant families regularly used in traditional cosmetics in Mayotte. In order to give a direction to the research, two technics where used. At first, the plants and their families used in the pharmacopeia of neighboring regions were inventoried using the literature. The resulting inventory was then compared with the flora of the Mahoran territory. The second technique was the realization of a semi-structured survey with people known for their plant-use knowledge in Mayotte. In order to have significant results, the ethnobotanical survey was done following Trotter & Logan’s protocol. (1986) According to that protocol, the gathered data has to be the following: common name, place of harvest, part used and the posology. Moreover the number of informant has to be big enough in order to integrate the data in several indicators such as: The informant agreement ration (IAR), the fidelity level (FL) and use value (UV). The number of informant was determined based on the population density of the different communes of the island. Another critical factor for this study is the correct identification of each sample. To achieve that when a sample was realized, it was taken twice. One for the analysis, the second sample was pressed and dried so as to enter a herbarium for identification. The last important step of this part of the study is the development of fast technics to establish the samples’ physiological activity. These test will give us qualitative information in order the isolate the plants that show a true potential. The targeted activities and tests being: - Anti-tyrosinase activity through an inhibition of tyrosinase test. - Anti-free-radicals activity through the DPPH test. - Anti-inflammatory activity through an inhibition of lipoxygenase an cyclooxygenase test The following steps of the study is the complete analysis of the physiologically active plants extracts in order to identify the active molecules. The end of the study will result in the creation of cosmetics originating from Mayotte’s flora. The way the cosmetics will be developed is thought so as it can be easily and durably done in Mayotte allowing this study to have a positive impact on the development of the island. [less ▲]

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See detail"Gérer ses émotions et agir : Pleine conscience et ACT" : Etude préliminaire de l'efficacité d'un groupe thérapeutique
Wagener, Aurélie ULg; Dierickx, Christophe; Herbeuval, Sandrine et al

Poster (2014, December 16)

Introduction : L’apprentissage de la gestion des émotions est une demande très fréquente en psychothérapie. Les techniques issues des programmes de pleine conscience et des thérapies d’acceptation et ... [more ▼]

Introduction : L’apprentissage de la gestion des émotions est une demande très fréquente en psychothérapie. Les techniques issues des programmes de pleine conscience et des thérapies d’acceptation et d’engagement ont notamment pour objectif de guider les clients dans cet apprentissage. Afin de répondre à cette demande, nous avons mis en place un groupe « Gérer ses émotions et agir : pleine conscience et ACT » et mené une recherche-action afin d’en tester l’efficacité. Méthodologie : Le cycle thérapeutique comportait 3 séances (3x3 heures) sur un délai de 6 semaines et 2 temps d’évaluation (avant la première séance [T0] et après la dernière [T1]). Les évaluations adminis-trées aux différents temps concernaient les données socio-démographiques, l’humeur, le niveau de pleine conscience, la flexibilité psychologique, le niveau d’engagement dans des activités, la mo-tivation et le sentiment d’auto-efficacité. Résultats : Cinq adultes (M âge = 37,46; ET = 7,96) ont participé à ce premier cycle. Les analyses prélimi-naires indiquent un effet significatif du facteur temps (N = 5). Ainsi, une augmentation du niveau d’engagement dans des activités (F(1) = 20,07, p = 0,01), de la motivation (F(1) = 15,00, p = 0,02) et du sentiment d’auto-efficacité (F(1) = 17,48, p = 0,02) est observée entre le T0 et le T1. Conclusion : Les résultats préliminaires semblent indiquer que les participants au groupe thérapeutique tirent des bénéfices de la participation à ce cycle thérapeutique. La récolte des données et la constitution d’un groupe contrôle se poursuivent. Les résultats seront plus longuement discutés lors du congrès. [less ▲]

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See detailRuzagayura, la grande famine du Rwanda moderne
Singiza, Dantès ULg

Poster (2014, December 16)

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See detailRelation entre fatigue et travail chez des patients atteints de sclérose en plaques
DELRUE, Gaël ULg; Blavier, Adelaïde ULg; Hennen, Julie et al

Poster (2014, December 15)

Fatigue is one of the most frequent symptom in multiple sclerosis patients (MS patients). We showed significant correlations between fatigue levels and difficulties encountered by our patients at work ... [more ▼]

Fatigue is one of the most frequent symptom in multiple sclerosis patients (MS patients). We showed significant correlations between fatigue levels and difficulties encountered by our patients at work evaluated through a specific questionnaire we already validated . This complaint must be carefully managed by professionnals in order to help the patients cope with it in the best way for maintaining work situation. [less ▲]

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See detailEvaluation of two capture methods in the assessment of species richness of eusocial bees in Gabon
Fabre Anguilet, Edgard ULg; Bengone Ndong, Toussaint; Francis, Frédéric ULg et al

Poster (2014, December 13)

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See detailDetection of rRNA synthesis sites within reptilian nucleoli
Bartholomé, Odile ULg; Thiry, Marc ULg; Franck, Claire

Poster (2014, December 13)

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See detailA morphospace for the marine angelfishes (Pomacanthidae): patterns of diversity
Frederich, Bruno ULg

Poster (2014, December 12)

The Pomacanthidae (marine angelfishes) is an iconic reef fish family of about 88 species. They have a circum-global distribution on tropical to warm-temperate reefs. Marine angelfishes occupy a diverse ... [more ▼]

The Pomacanthidae (marine angelfishes) is an iconic reef fish family of about 88 species. They have a circum-global distribution on tropical to warm-temperate reefs. Marine angelfishes occupy a diverse range of trophic niches, ranging from spongivory and algivory to zooplanktivory. Previous morpho-functional analysis of this family mainly focused on the head region and gut morphology in a limited number of species. However a morphological study including a large sample of angelfish representatives is currently lacking. Here, I explore the diversity of body morphology in this reef fish group. I collected x-ray images of 228 museum specimens from 71 species and I used landmark-based geometric morphometrics to quantify the overall body shape variation within this family. In a test for interspecific allometry, the linear regression of shape variables onto size (LogTL; TL = total length) was significant (P < 0.001). However, the percentage of explained variance in this model (23%) showed no strong relation between size and body shape. Main shape variation across species was explored using a principal component analysis on shape variables. The two main axes (PC1 and PC2) explained 74% of the total variance of the dataset. Pomacanthus spp., which mainly feed on fixed invertebrates (sponges and tunicates), have deep body with high and angular cephalic profile (lowest values along PC1). Conversely, the zooplanktivorous Genicanthus spp., those have a more pelagic lifestyle, show a slender body with shorter anal fin (highest values along PC1). The pigmy angelfishes from the genus Centropyge, which group different diets (omnivory or algivory), show a more robust and rectangular body shape (high scores along PC2). This work provides the row data for future studies dealing with the mode of phenotypic diversification of Pomacanthidae during evolution. [less ▲]

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See detailGenetic structure of fragmented southern populations of African Cape Buffalo (Syncerus caffer caffer) based on microsatellite analysis
Smitz, Nathalie ULg; Cornélis, Daniel; Chardonnet, Philippe et al

Poster (2014, December 12)

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See detailImpact of goldfish on terrestrial and aquatic microhabitat use in the palmate newt
Darnet, Elodie; Winandy, Laurane ULg; Denoël, Mathieu ULg

Poster (2014, December 12)

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See detailRapid morphological change of barbels (Cyprinidae) after the dry-up of Sahara
Brahimi, Amina; Tarai, Nacer; Libois, Roland ULg

Poster (2014, December 12)

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See detailHoney bee colony strength - Assessing accuracy of the Liebefeld estimation method
Leclercq, Gil ULg; Gengler, Nicolas ULg; Francis, Frédéric ULg et al

Poster (2014, December 12)

Honey bee colony strength (number of adult bees in a colony) is a crucial character used for both breeding and research. In breeding programs a rough estimate is usually sufficient to select strong ... [more ▼]

Honey bee colony strength (number of adult bees in a colony) is a crucial character used for both breeding and research. In breeding programs a rough estimate is usually sufficient to select strong colonies. On the other hand, the accuracy of this character can deeply affect the quality of several studies in both fundamental and applied research. For example these studies are related to the assessment of low demographic variations following a stress, or the estimate of a host-parasite ratio (e.g. involving the mite Varroa destructor Anderson & Trueman). The “Liebefeld estimation method” is extensively used in these studies while its accuracy remains weakly documented. Our goal is to provide more information on the accuracy of this method. [less ▲]

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See detailA gammaherpesvirus infection protects against allergic asthma.
Machiels, Bénédicte ULg; Dourcy, Mickael ULg; Sabatel, Catherine ULg et al

Poster (2014, December 12)

The “hygiene hypothesis” proposes that the augmentation of allergic diseases in developed countries could be linked to a reduced exposure to infections during childhood. Surprisingly, the potential ... [more ▼]

The “hygiene hypothesis” proposes that the augmentation of allergic diseases in developed countries could be linked to a reduced exposure to infections during childhood. Surprisingly, the potential protective role of herpesvirus infections against allergy development has never been addressed directly. In this study, we used the Murid herpesvirus 4 (MuHV-4) to study the impact of a persistent gammaherpesvirus infection on the development of House Dust Mites (HDM)-induced allergic asthma. Our results revealed that MuHV-4 infection affects both the sensitization and the challenging phases of HDM-induced airway allergy. In particular, we highlighted that MuHV-4 infection strongly impacts the lung innate immune response. Indeed, while the dendritic cells remained competent to uptake antigens and to migrate to the draining lymph nodes, MuHV-4 infection impaired their ability to trigger HDM sensitization. In the future, these results could allow us to develop strategies to prevent the development of TH2-skewed responses against respiratory allergens. [less ▲]

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See detailWhen microplastic is not microplastic: ingestion of artificial cellulose fibers by macrofauna living in seagrass macrophytodetritus
Collard, France ULg; Remy, François ULg; Gilbert, Bernard ULg et al

Poster (2014, December 12)

Vagile macroinvertebrates associated with Posidonia oceanica exported litter were sampled in August 2011, November 2011 and March 2012 in the Calvi Bay (Corsica), near the STARESO oceanographic station ... [more ▼]

Vagile macroinvertebrates associated with Posidonia oceanica exported litter were sampled in August 2011, November 2011 and March 2012 in the Calvi Bay (Corsica), near the STARESO oceanographic station. Contents of digestive tracts were analyzed and fibers of various sizes and colors were found. Fibers were found in 27.6% of the digestive tracts in the nine dominant species. No correlation was found between number of fibers and taxonomic or trophic level. There were no seasonal or spatial preferences and thus we hypothesize that the organisms ingest these fibers randomly throughout the year. Analyses performed with a Raman spectroscope showed that these fibers were composed of cellulose associated with a coloring agent following the fiber color. Red fibers were dyed with the Direct Red 28, blue fibers were dyed with Direct Blue 22. Analyses by a scanning electron microscope (SEM) showed that cellulose fibers had the particular morphology of artificial cellulose fibers called: viscose. Our SEM analyses were compared to literature. This comparison assessed that fibers found in digestive tracts were made of viscose. In a first approach, viscose fibers looked like microplastic fibers because of their color and shape. However, it appeared that these fibers were made of artificial cellulose which is very different than plastic in terms of impacts and fate in the organisms. This study highlights the importance of physico-chemical analyses such as Raman spectroscopy and SEM to certainly identify the composition of particles ingested by organisms. From an ecological point of view, the red coloring agent is known to be carcinogenic in mammals and fish. Consequently, this pollution could provoke an environmental problem for the P. oceanica litter vagile macrofauna. [less ▲]

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See detailShedding light on two unstudied species of Lepilemur in Northwest Madagascar
Wilmet, Leslie ULg; Beudels-Jamar, Roseline C.; Schwitzer, Christoph et al

Poster (2014, December 12)

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See detailAre amphipods influenced by Posidonia oceanica seagrass features?
Sturaro, Nicolas ULg; Lepoint, Gilles ULg; Michel, Loïc ULg et al

Poster (2014, December 12)

In the Mediterranean Sea, the seagrass Posidonia oceanica plays an important role as habitat for invertebrates, among which amphipod crustaceans represent a dense and diverse assemblage. Recent studies ... [more ▼]

In the Mediterranean Sea, the seagrass Posidonia oceanica plays an important role as habitat for invertebrates, among which amphipod crustaceans represent a dense and diverse assemblage. Recent studies have observed that amphipod density and biomass vary significantly on small spatial scales. This patchiness may be caused by different factors, such as recruitment, competition, and predation; however, habitat features, resulting in availability of resources such as food or shelter, may also be important in structuring these assemblages. This study examined the relationships between amphipod and habitat features in a P. oceanica meadow of the Revellata Bay (Corsica). The sampling was carried out in a continuous meadow colonizing soft substrates at constant depth in August 2008. We quantified the density and biomass of each amphipod species, as well as habitat features, namely shoot density, leaf and epiphyte biomasses, percentage of leaves per shoot having alteration marks and litter biomass. Using multiple regression analyses, few weak significant relationships were identified between amphipod and habitat features. The number of species and the diversity appeared unaffected by the measured habitat features. In contrast, total amphipod density and biomass were generally positively related to the shoot density and epiphyte biomass of P. oceanica, respectively. Overall, habitat features accounted for 0-30% of the variation in the densities of the amphipod species. A distance-based linear model explained a total of 25.8% of the variation of the amphipod assemblages (of which 18.6% was explained by litter biomass). Amphipods are therefore influenced by some P. oceanica features, but only weakly. Furthermore, some features appeared to influence individual species whereas others functioned at the assemblage level. The main challenge remains in evaluating the scale at which these features act and the way in which they influence the structure of assemblages. [less ▲]

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See detailSpatial variation in the concentrations of mercury and persistent organic pollutants in free-ranging bottlenose dolphins (Tursiops truncatus) from South Florida
Damseaux, France ULg; Kiszka, Jeremy; Heithaus et al

Poster (2014, December 12)

The bottlenose dolphin (Tursiops truncatus) is an abundant apex predator found in nearshore waters of South Florida, especially in the Lower Florida Keys (Key West) and the coastal waters of Everglades ... [more ▼]

The bottlenose dolphin (Tursiops truncatus) is an abundant apex predator found in nearshore waters of South Florida, especially in the Lower Florida Keys (Key West) and the coastal waters of Everglades National Park (ENP). The objective of this study was to assess variation in contamination levels of total mercury (T-Hg) and persistent organic pollutants (NDL-PCBs, PBDEs, DDT, HCH, HCB, PCDD/Fs and DL-PCBs) in bottlenose dolphins found offshore of the densely populated Key West (n = 27) and from undeveloped ENP (n = 20). T-Hg and POPs were analysed in skin and blubber, respectively, by the mean of Direct Mercury analyser (for THg), GC-ECD (POPs) and GC-HRMS (DLCs). The 7 ICES PCBs were the main compounds found in bottlenose dolphins from Key West (8229 ng.g-1 lipids) and the ENP (2289 ng.g-1 lipids), while the concentrations of PCDD/Fs remained low (Key West: 104 pg.g-1 lipids, ENP: 102 ng.g-1 lipids). POP concentrations were higher in individuals from Key West compared to those from the ENP. However, POPs concentrations in Key West dolphins were lower than those from other locations in Florida and around the world. Unlike organic pollutants, T-Hg concentrations were significantly higher in ENP dolphins (Key West: 2941 ng.g-1 dw versus ENP: 9314 ng.g-1 dw) highlighting the specific cycle of Hg in mangrove ecosystems. To conclude, sources of T-Hg and POPs differed between Key West and ENP as reflected by their concentrations in skin and blubber of free-ranging bottlenose dolphins highlighting their role as sentinels of their environment. [less ▲]

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See detailStable isotope ratios reveal trophic niche partitioning among hermit crabs from tropical polyspecific seagrass meadows
Michel, Loïc ULg; Frederich, Bruno ULg; Lavitra, Thierry et al

Poster (2014, December 12)

Polyspecific seagrass meadows are ubiquitous features of tropical coastal zones. These ecosystems are of critical ecological importance, and provide a wide range of socio-economical services to local ... [more ▼]

Polyspecific seagrass meadows are ubiquitous features of tropical coastal zones. These ecosystems are of critical ecological importance, and provide a wide range of socio-economical services to local populations. Meadows however undergo multiple threats linked to human activities (increased nutrient input, overfishing, invertebrate overharvesting, etc.). It is currently hard to assess how seagrass meadows could respond to anthropogenic impacts due to poor knowledge of their functional ecology. In an effort to unravel trophic interactions ruling the food webs associated to seagrass beds of the Toliara Great Reef (SW Madagascar), we studied resource segregation between two common Diogenidae hermit crabs (Dardanus scutellatus and Ciliopagurus tricolor) using stable isotope ratios. Interspecific differences were noted in isotopic composition of carbon (δ13C = -12.22 ± 1.73 ‰ for D. scutellatus, δ13C = -14.55 ± 0.73 ‰ for C. tricolor), nitrogen (δ15N = 4.73 ± 0.53 ‰ for D. scutellatus, δ15N = 5.20 ± 0.61 ‰ for C. tricolor) and sulfur (δ34S = 14.08 ± 2.32 ‰ for D. scutellatus, δ34S = 16.73 ± 1.49 ‰ for C. tricolor), suggesting that the two species do not feed on the same items. In addition, SIBER (Stable Isotope Bayesian Ellipses in R) modeling based on C and N data clearly showed that no overlap was present in the core isotopic niches of the two species. It also indicated that the isotopic niche of D. scutellatus was greater than the one of C. tricolor, implying that the former feeds on a greater number of items than the latter. While hermit crabs are generally considered as omnivorous species, this study highlighted differences in the foraging ecology of D. scutellatus and C. tricolor. These differences could help to limit competition for food between these two species, and facilitate their coexistence in Malagasy seagrass beds. [less ▲]

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See detailImpact of Climate Change on “Aphid - Natural Enemies” Relationship
Boullis, Antoine ULg; Oostrom, Marjolein; Francis, Frédéric ULg et al

Poster (2014, December 12)

While the effects of global atmospheric changes on vegetation and associated insect populations (bottom-up interactions) are increasingly studied, how these gases affect the interactions between insects ... [more ▼]

While the effects of global atmospheric changes on vegetation and associated insect populations (bottom-up interactions) are increasingly studied, how these gases affect the interactions between insects and their natural enemies (top-down interactions) is less clear. As the efficacy of natural enemies is governed largely by behavioral mechanisms, changes in their prey-seeking behavior or the behavior of insect prey defenses can change the dynamics of insect populations. The impact of increases in atmospheric carbon dioxide concentrations on aphid population dynamic is well documented. However, nothing about their chemical ecology is reported in the literature. Aphids are using many chemical signals to communicate with each other or with their environment. For example aphids produce an alarm pheromone to signal the presence of a natural enemy (such as a predator or a parasitoid) in the colony. Moreover, this pheromone is used by natural enemies as a kairomone to locate aphid prey, and is thus at the center of aphid – natural enemies interactions. In this study, the impact of elevated CO2 concentration on the emission of the alarm pheromone in the aphid A. pisum is studied. Using a zNoseTM (Gas chromatograph enabling the fast analyze of the chemical composition of a sample), the kinetic of the EBF emission in real-time is set up for a single individual predated by a coccinellid predator Harmonia axyridis Pallas. This experimentation is done both for aphids reared under ambient atmospheric conditions and for individuals reared under elevated CO2 concentrations. We present the differences in terms of emission dynamic and discuss the potential of these results in terms of biological control. [less ▲]

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See detailSound production in piranhas and relatives: preliminary results
Melotte, Geoffrey ULg; Michel, Christian ULg; Parmentier, Eric ULg

Poster (2014, December 12)

Acoustic communication plays an important role in the life of many teleost species where it is mainly involved in agonistic and/or courtship behaviour(s). Despite the large number of species in the family ... [more ▼]

Acoustic communication plays an important role in the life of many teleost species where it is mainly involved in agonistic and/or courtship behaviour(s). Despite the large number of species in the family Serrasalmidae (92 species), sound production has been described only in some of them, particularly in the genera Serrasalmus and Pygocentrus. The aim of this study is to investigate the sound producing abilities of different Serrasalmidae species and to understand the corresponding mechanisms. Two herbivorous species of Serrasalmidae, Piaractus brachypomus and Metynnis lippincottianus, produce sounds composed of a single pulse. The mechanism involved in these species is not yet understood. In contrast, the calls emitted by several species of Serrasalmus and Pygocentrus are harmonic sounds composed of several pulses without inter-pulse interval. Their mechanism results from the forced vibration of the swimbladder following the contraction of sonic muscles that are attached to tendons surrounding ventrally the bladder. Another species, Pygopristis denticulata, is able to produce two types of sounds. The first sound consists of several pulses with irregular pulse period and is likely produced by a sonic muscle inserting on the skull and on the rostral part of the swimbladder. The second sound is multi-pulsed and, contrary to all other sounds described here, possesses a high dominant frequency suggesting a mechanism that does not involve the swimbladder and that remains to be determined. According to these results, Serrasalmidae seems to contain many species able to produce sounds by means of different mechanisms. [less ▲]

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See detailLes ressources génétiques caprines en Algérie
Moula, Nassim ULg; Philippe, François-Xavier ULg; Ait Kaki, Asma et al

Poster (2014, December 06)

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See detailPaleolithic projectiles and their projecting mode
Coppe, Justin ULg

Poster (2014, December 06)

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See detailL'Aurignacien de la grotte Yafteh et son contexte
Otte, Marcel ULg; Flas, Damien ULg; Zwyns, Nicolas et al

Poster (2014, December 06)

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See detailDoes the cover crop residue management affect the soil water availability for plants?
Chelin, Marie ULg; Parvin, Nargish ULg; Hiel, Marie-Pierre ULg et al

Poster (2014, December 05)

Hydraulic processes and soil storage capacity may be affected by the crop residue management. Thus, a better understanding of the spatial and temporal distribution of water as a consequence of different ... [more ▼]

Hydraulic processes and soil storage capacity may be affected by the crop residue management. Thus, a better understanding of the spatial and temporal distribution of water as a consequence of different tillage methods is needed. The distribution of soil water content is basically studied thanks to soil moisture sensors such as time domain reflectometry (TDR) probes. However, this method requires the disturbance of the soil and only provides local information. Comparatively, electrical resistivity tomography (ERT) slightly alters the soil structure. It has been considered as a proxy to assess the spatial and temporal variability of the soil water content. This study aims at assessing whether and to which extent the crop residue management influences soil water dynamics and the water availability for maize. Water content will be monitored from March to October 2014, under three crop residue managements: conventional tillage realized in the end of autumn, conventional tillage realized just before sowing, and strip tillage. A bare soil under conventional tillage will also be monitored so as to better understand the influence of the plant over the growing season. So as to better understand the dynamics of water in the soil-water-continuum, the influence of the crop residue management on the soil structure and the plant development will also be investigated. The soil water pattern will be daily monitored on a surface of two square meters through surface stainless steel electrodes, corresponding to three rows of seven maize plants. Five additional sticks with buried electrodes will be setup to get more detailed information near to the maize row. For each of the monitored zone, two TDR probes will help validating the data. In order to calibrate the relationship between electrical resistivity and soil water content, a dig will be dug, in which a set of four electrodes, one TDR probe and one temperature sensor will be placed at four different depths. Two suction cups placed on each of the monitoring zone will help getting the electrical conductivity of the soil solution. [less ▲]

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See detailFirst principles study of the structural, electronic and thermoelectric properties of misfit cobaltite
Lemal, Sébastien ULg; Varignon, Julien ULg; Bilc, Daniel ULg et al

Poster (2014, December 03)

In the context of environmental issues that become more and more prevalent in our society, there has been recently an increase of interest for thermoelectric (TE) materials, which have the property to ... [more ▼]

In the context of environmental issues that become more and more prevalent in our society, there has been recently an increase of interest for thermoelectric (TE) materials, which have the property to convert heat into electricity, and vice-versa. Although they do not display exceptional thermopower (in comparison to best thermoelectric like bismuth telluride), oxide materials have attracted some attention for high-temperature TE applications, due to their high stability. Amongst them, CoO2-layered compounds were proposed as good p-type TE candidates. Still, these compounds have been only poorly characterized both theoretically and experimentally. In this work we report a first-principles study of misfit calcium cobaltite (Ca2CoO3)(CoO2)1.618 based on density functional theory and an hybrid functional. The computed structural, electronic and magnetic properties match well the avalaible experimental data. Then the thermoelectric properties can be deduced using the Boltzmann transport formalism within the constant relaxation time approximation and will be discussed. [less ▲]

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See detailDetecting microbial patterns in relation to soil agricultural practices and the plant development stage
Degrune, Florine ULg; Dufrêne, Marc ULg; Taminiau, Bernard ULg et al

Poster (2014, December 02)

Agricultural practices have a strong impact on soil bacteria and fungi. Furthermore, microbial community composition can change with the stage of plant development. We are interested in exploring these ... [more ▼]

Agricultural practices have a strong impact on soil bacteria and fungi. Furthermore, microbial community composition can change with the stage of plant development. We are interested in exploring these effects in relation to changes induced by agriculture and plant stage in soil conditions. Some bacteria are influenced only by the plant stage, which induces changes in soil humidity, pH, nitrates, and carbon. We would thus expect these bacteria to be highly sensitive to these parameters. Other bacteria are affected only by the tillage practice applied. Further study is needed to identify the soil parameters responsible for this effect. The plant stage also has a great impact on fungal community composition. [less ▲]

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See detailMid-winter freeze experiment in the Arctic Ocean: Norwegian Young sea ICE cruise (N-ICE2015)
Nomura, Daiki; Granskog, Mats A.; Fransson, Agneta et al

Poster (2014, December 02)

In mid-January 2015, RV Lance will freeze into the ice north of Svalbard, Arctic Ocean at around 83.25°N 30°E, and passively drift with the ice as part of the Norwegian Young sea ICE cruise (N-ICE2015 ... [more ▼]

In mid-January 2015, RV Lance will freeze into the ice north of Svalbard, Arctic Ocean at around 83.25°N 30°E, and passively drift with the ice as part of the Norwegian Young sea ICE cruise (N-ICE2015). Judging from historic sea ice drift trajectories, it is likely that RV Lance will drift in a SW direction and the ship will probably be freed from the ice in mid spring after about two to three months of drift. Thereafter, RV Lance will return to her starting position and start a new drift. Under all circumstances, the ice drift project will end in late June 2015. Throughout the cruise the focus will be on the interaction of the atmosphere-ice-ocean system and the response of the marine ecosystem to the thinner ice regime. The overall goal of the project team is to improve our understanding of the role of the younger ice pack in the Arctic on greenhouse gas fluxes and to ultimately assess whether the Arctic Ocean is a sink or source of greenhouse gases. We plan to conduct long-term synchronous observations of Arctic snow and sea ice biogeochemistry and physics and fluxes of carbon dioxide, methane, nitrous oxide and bromoform. This work targets at filling a crucial gap in our understanding of the role of Arctic sea ice in the climate system. This is done by conducting state of the art observations on Arctic sea ice in the polar night, when observations are basically non-existent. Further we are focusing on the new thinner ice regime, which is even less documented. We aim to understand how the thinner sea ice in the Arctic basin contributes (i) to important greenhouse gas exchange between the atmosphere and ocean and (ii) to aerosol formation, that contribute to the radiative balance of the planet. This work will increase direct collaboration between Japanese and European scientists in the Arctic, and combines complimentary expertise and experience from several international partners to carry out the interdisciplinary work proposed. [less ▲]

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See detailPoster session 1: Wednesday 3 December 2014, 09:00-16:00Location: Poster area.
Romano, G.; D'ancona, G.; Pilato, G. et al

Poster (2014, December)

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See detailStigmergy as a mechanism to produce collective vortex behaviours: a study case in shoveler duck
Delcourt, Johann ULg; bode, W. Nikolaï

Poster (2014, December)

Ant mill, caterpillar circle, bat donut, bacteria vortex, duck swirl and fish torus are different names for rotating circular formations of animals, where individuals turn around a common centre. Even if ... [more ▼]

Ant mill, caterpillar circle, bat donut, bacteria vortex, duck swirl and fish torus are different names for rotating circular formations of animals, where individuals turn around a common centre. Even if the ubiquity of this behavioural phenomenon might have suggested common causes or fundamental underlying principles across contexts, a variety of proximate mechanisms can give rise to vortex behaviours. Here, we investigate if stigmergic process (mechanism of self-organisation wit hout direct communication or interaction between individuals) is able to produce different collective behaviours, notably collective vortices. We present an individual-based simulation model for the movement of populations in a resource landscape that allows us to vary the strength of the interactions mentioned above. The key assumption and novelty of our model is that individuals can cause the release of additional nutrients, as well as consuming them. Our model produces clear predictions. For example, we expect more tortuous individual movement paths and higher levels of aggregation in populations occupying homogeneous environments where individual movement makes more nutrients available. We also show how observed movement dynamics could change when local nutrient sources are depleted or when the population density increases. Our predictions are testable and qualitatively reproduce the different feeding behaviours observed in filter-feeding ducks (Anas clypeata), for example. We suggest that considering two-way interactions between feeding individuals and resource landscapes could help to explain fine-scale movement dynamics. [less ▲]

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See detailSchistosoma mansoni egg-induced inflammation inhibits γ-herpesvirus replication
Dougall, Annette ULg; Rolot, Marion ULg; Vanderplasschen, Alain ULg et al

Poster (2014, December)

Geographically, S. mansoni overlaps with human γ-herpesvirus infections such as Kaposi’s sarcoma-associated herpesvirus. The strongly regulated Th2-type immune response generated during infection by S ... [more ▼]

Geographically, S. mansoni overlaps with human γ-herpesvirus infections such as Kaposi’s sarcoma-associated herpesvirus. The strongly regulated Th2-type immune response generated during infection by S. mansoni may jeopardize or improve the host’s ability to generate effective immunity against co-infecting pathogens, such as viruses. Here, we have trialled two approaches using murine herpesvirus-4 (MuHV-4). The first used a S. mansoni egg model to induce lung granulomas followed by intranasal infection with the MuHV-4-luc+ recombinant virus. Alternatively, we naturally infected mice with S. mansoni cercariae to induce a systemic Th2-type response and granulomas in the liver and intestine before intranasal MuHV-4-luc+ infection. We observed in both models a significant reduction of MuHV-4 replication in the lungs at day 5 and 7 pi associated with reduced weight loss caused by MuHV-4 infection. These results indicate that helminth induce Th2-type responses could inhibit and protect against viral infection. [less ▲]

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See detailOn Damage Characterization of a Steel Sheet
Guzmán Inostroza, Carlos Felipe ULg; Habraken, Anne ULg

Poster (2014, December)

Ductile damage is a physical phenomena which involves progressive deterioration of mechanical properties of metals, when undergoing high deformations. Compared to plasticity, the physical mechanisms ... [more ▼]

Ductile damage is a physical phenomena which involves progressive deterioration of mechanical properties of metals, when undergoing high deformations. Compared to plasticity, the physical mechanisms behind damage are more complex and the microscale is not longer negligible. In mathematical damage models, founding an optimal set of material parameters can be a hard task due to the strong coupling and non-linearity of the equations. An identification strategy is then crucial to arrive to a general set of parameters. Therefore, we address the fully characterization of a ferritic steel sheet, involving the elasto-plastic and damage parameters. This poster presents an hybrid experimental-numerical procedure, coupling numerical simulations, optimization algorithms and digital image correlation measurements, over a set of representative experimental and numerical results of tensile, shear and plane strain tests in different material directions. Due to the small thickness of the sheet, the constitutive model is very prone to localization into a shear band difficulting the damage parameters identification. It is found that a porosity induced inhomogeneity plus a mixed hardening can delay localization and represent the entire deformation range of the tests, leading to acceptable results. Different set of parameters are also obtained and then validated with experimental results. This localization phenomena should be carefully considered in applications involving complex strain paths. [less ▲]

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See detailThe thyroid gland and thyroid hormones in sheepshead minnow (Cyprinodon variegatus) during early development and metamorphosis
Schnitzler, Joseph ULg; Benichou, Farida; Klaren, PHM et al

Poster (2014, December)

The sheepshead minnow is widely used in ecotoxicological studies that recently, begin to focus on potential disruption of the thyroid axis by xenobiotics and endocrine disrupting compounds. However ... [more ▼]

The sheepshead minnow is widely used in ecotoxicological studies that recently, begin to focus on potential disruption of the thyroid axis by xenobiotics and endocrine disrupting compounds. However, reference levels of thyroxin (T4) and 3,5,3’-triiodothyronine (T3) and their developmental patterns are unknown. This study set out to describe the ontogeny and morphology of the thyroid gland in sheepshead minnow, and correlate these with whole body concentrations of thyroid hormones during early development and metamorphosis. Couples of three females and two males were placed in breeding chambers designed for this experiment. More than 1000 eggs were collected and maintained in seawater. Embryos were selected under a dissection microscope and placed in incubation dishes (50 per dish) at 25°C. On day 6, embryos hatched and larvae were transferred to 1L beakers. For one week after hatching, larvae were fed on artemia, and from 8 to 30 days post-hatch they were fed on flaked fish food. Embryos were sampled on day 0, 3, 6 post-fertilization and larvae and juveniles were sampled every three days from day 0 to 28 days post-hatch. The pooled samples were taken from several incubation dishes and divided in three replicate batches of 10-30 individuals. T4 and T3 were extracted from whole fish bodies and an enzyme-linked immunoassay was used to measure whole-body hormone levels. At each sampling point 5 individuals were placed in formalin fixative for histology. Length and body mass were measured. Hatching success, gross morphology, thyroid hormone levels and histology data were recorded. The onset of metamorphosis at 12 days post-hatching coincided with surges in whole body T4 and T3 concentrations. Thyroid follicles were first observed in pre-metamorphic larvae at hatching, and were detected exclusively in the subpharyngeal region, surrounding the ventral aorta. Follicle size and epithelial cell heights varied during the developmental phase, indicating fluctuations in thyroid hormone synthesis activity. The increase in the whole body T3/T4 ratio was indicative of an increase in outer ring deiodination. This study establishes a baseline for thyroid hormones in sheepshead minnows, which will be vital for the understanding of thyroid hormone functions and in future studies of thyroid toxicants in this species. [less ▲]

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See detailCytoskeletal changes in supporting cells of the auditory organ during development in rodents: the appearance of 15-protofilament microtubules and β5-tubulin isoform.
Renauld, Justine ULg; Thelen, Nicolas ULg; Johnen, Nicolas et al

Poster (2014, December)

A feature of the supporting cells of the organ of Corti is the presence of an abundant cytoskeleton which is mainly composed of microtubules. These supporting cells have also been shown to contain a minor ... [more ▼]

A feature of the supporting cells of the organ of Corti is the presence of an abundant cytoskeleton which is mainly composed of microtubules. These supporting cells have also been shown to contain a minor mammalian tubulin, the β5-tubulin [1], recently reported to be a biomarker for cancer outcome [2] and cell proliferation [3]. It was shown that a β-tubulin isoform can specify the microtubule architecture, as seen with the expression of the Moth β2 tubulin in the Drosophila testes which imposes the 16-protofilament (16pf) structure on the corresponding subset of Drosophila microtubules, which normally contain 13pf [4]. Moreover, supporting cell microtubules are formed by 15pf instead of the canonical 13, a unique fact among vertebrates [5]. Such a protofilament configuration has been observed in C. elegans’ neurons which are responsible for the mechanosensory sense of touch [6]. It was also shown that these 15pf microtubules were essential to the proper functioning of these mechanosensory neurons [6]. To determine the role of this particular tubulin in the auditory organ and its possible involvement in the formation of the unusual 15pf microtubules of supporting cells, we studied the spatiotemporal localization of β5-tubulin during development in rats from embryonic day 18 until P25 (25th postnatal day). Then we examined the fine structure of microtubules at the transmission electron microscope level. Our results showed that β5-tubulin, contrary to other β-tubulins, had a unique distribution in the cochlea. This β-tubulin appeared at a postnatal stage, before the opening of the Corti’s tunnel and are restricted to supporting cells, especially in pillar and Deiters’ cells. Electron microscopy further indicated that pillar and Deiters cells were composed by 13pf microtubules at P2, but by 15pf microtubules at P25. In conclusion, the architecture of microtubules seems to evolve during the development of the organ of Corti. Furthermore, β5-tubulin has the same localization than this structure and could be an interesting target. [less ▲]

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See detailWhat can we learn from asteroseismology of β Cephei stars through forward approach modelling?
Salmon, Sébastien ULg; Montalban, J.; Miglio, A. et al

Poster (2014, December)

The beta Cephei pulsating stars present a unique opportunity to test and probe our knowledge on the interior of massive stars. The information we can obtain depends on the quality and number of ... [more ▼]

The beta Cephei pulsating stars present a unique opportunity to test and probe our knowledge on the interior of massive stars. The information we can obtain depends on the quality and number of observational constraints, both seismic and classical ones. The asteroseismology of beta Cephei stars proceeds by a forward approach, which often result in multiple solutions, without clear indication on the level of confidence. We seek a method to derive confidence intervals on stellar parameters obtained by forward approach and investigate how these latter behave depending the seismic data accessible to the observer. We realise forward modelling with help of a grid of pre-computed models and use Monte-Carlo simulations to build confidence intervals on the inferred stellar parameters. We apply and test this method in a series of hare and hound exercises on a subset of theoretical models simulating observed stars. Results show that a set of 5 frequencies (with knowledge of their associated angular degree) yields good seismic constraints. In particular, presence of mixed modes provides a strong diagnosis on the evolutionary state of the star. Significant errors on the determinination of the extent of the central mixed region appear when the theoretical models do not present the same chemical mixture as the observed star. [less ▲]

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See detailEvaluation of the impact of Triclosan on the functioning of the thyroid system in Cyprinodon variegatus L., 1803.
Rahmouni, Chahrazed; Benichou, Farida; Klaren, PHM et al

Poster (2014, December)

Triclosan (5-chloro-2-[2, 4-dichlorophenoxy] phenol) is an antimicrobial widely used in various industrial products such as textiles, cosmetics and body care products. It is often detected in aquatic ... [more ▼]

Triclosan (5-chloro-2-[2, 4-dichlorophenoxy] phenol) is an antimicrobial widely used in various industrial products such as textiles, cosmetics and body care products. It is often detected in aquatic environments. The presence of the main biotransformation product, methyl TCS, indicates that this compound is not only degraded, but also persistent and accumulates in aquatic organisms. In this study, the effects of TCS on the thyroid system during embryonic and larval stages in Cyprinodon variegatus were evaluated. In particular, whole body thyroid hormone levels and the activity of deiodinases, enzymes involved in the activation of the thyroid prohormone T4, were measured. Couples of three females and two males were placed in breeding chambers designed for this experiment from which 3832 eggs were obtained by reproduction in the laboratory. Eggs were collected and maintained in seawater. Embryos were selected under a dissection microscope, randomly assigned to each of five treatment groups: Control, DMSO control (vehicle), 20 μg/L TCS, 50 μg/L TCS and 100 μg/L TCS and placed in incubation dishes (50 per dish) at 25°C. On day 6, embryos hatched and larvae were transferred to 1L dishes. The larvae were fed on artemia and on flaked fish food till day 15 post hatching when the fish were analyzed. The fertilization and survival rate, as well as the larval dry weight did not vary significantly between individuals exposed to 20, 50 and 100 μg/L TCS. T3 and T4 concentrations increased significantly in larvae exposed to 50 and 100 μg/L TCS. The study of the activity of enzymes involved in the deiodination of thyroid hormones (ORD) represents a new aspect in the study of endocrine disruption in C. variegatus. Unfortunately, we were not able to detect a net enzymatic T4 deiodination activity, most likely due to the very small amounts of protein and low specific enzyme activity in brain homogenates, carcass and liver. [less ▲]

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See detailTrace element kinetics in caged Mytilus galloprovincialis
Richir, Jonathan ULg; Lepoint, Gilles ULg; Donnay, Annick et al

Poster (2014, December)

Trace elements (TEs) remain contaminants of concern because of their persistence, ability to concentrate in organisms and toxicity. The Mediterranean mussel Mytilus galloprovincialis Lamarck, 1819 is a ... [more ▼]

Trace elements (TEs) remain contaminants of concern because of their persistence, ability to concentrate in organisms and toxicity. The Mediterranean mussel Mytilus galloprovincialis Lamarck, 1819 is a relevant bioindicator of TE coastal contamination. However, little research has studied the combined influence of environmental condition changes and physiological processes on their kinetics in that species. Caged M. galloprovincialis were thus immerged in 2 contrasted pristine Corsican (France) coastal environments, the semi-enclosed Diane salty pond and the open Calvi Bay, from February to June 2011. Mussels were regularly sampled to study the kinetics of 19 TEs in their flesh; dissolved and particulate TEs were also monitored. The primary production and the water physico-chemical variables were measured, and meteorological data were purchased from Météo-France. TE kinetics in mussels differed between sites. Mussel spawning, a temperature and saline-induced physiological process that occurred about 10 days later in the Diane pond, was followed by a short time increase of TE levels in the mussel flesh. Mussel contamination also evolved according to changes of their respective environmental TE levels. Raining events temporary led, in the Diane pond, to the water enrichment with TEs, nutrients and detrital material, to peaks of primary production and to the increase of TE concentrations in the mussel flesh. This step by step evolution of TE levels in the environment and mussels was afterwards followed by a rapid return to initial conditions. In the open Calvi Bay, these fast and balanced kinetics were not so obvious, because of the rapid dilution of environmental constrain effects in the Bay. Mussels are often used as bioindicator in estuaries and coastal enclosed meadows with rapidly changing environmental conditions. In such conditions, the influence of the environment on TE kinetics in mussels must be considered, in addition to physiological processes, when monitoring the TE coastal contamination. [less ▲]

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See detailIdentification de sous-groupes de glioblastome sur base de critères cliniques
Lambert, Jérémy ULg; Scholtes, Félix ULg; MARTIN, Didier ULg

Poster (2014, December)

Glioblastoma has terrible outcomes, but the disease evolution varies a lot between patients. We used a sample of 239 patients (EORTC 26981) and a validation sample of 93 patients (CHU Liège) to class ... [more ▼]

Glioblastoma has terrible outcomes, but the disease evolution varies a lot between patients. We used a sample of 239 patients (EORTC 26981) and a validation sample of 93 patients (CHU Liège) to class patients in groups with the same risk of recurrence. 4 distinct subgroups were created using recursive partitioning analysis. In the future, genetic profile will be compared between these groups to find markers of aggressiveness. Moreover, survival after recurrence is closely related to subgroups, and a surgical resection of the recurrence shows positive effect in each subgroup. [less ▲]

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See detailThe influence of bioavailable copper and zinc concentrations on metallothionein levels, DNA damage and gene expression in the polychaete Nereis (Alitta) virens (M. Sars, 1835)
Pini, Jennifer; Richir, Jonathan ULg; Watson, Gordon

Poster (2014, December)

Nereis (Alitta) virens is an ecologically and commercially important polychaete of intertidal soft sediment and an ideal species to investigate long term effects of metals. Using a spike approach, worms ... [more ▼]

Nereis (Alitta) virens is an ecologically and commercially important polychaete of intertidal soft sediment and an ideal species to investigate long term effects of metals. Using a spike approach, worms (1-3 g) were incubated for nine months in sediments spiked at environmentally relevant concentrations of copper, zinc and copper & zinc together: low (copper: 70 mg kg-1, zinc: 200 mg kg-1), medium (copper 120 mg kg-1, zinc: 270 mg kg-1) and high (copper 575 mg kg-1, zinc: 1160 mg kg-1) concentrations. These concentrations were based on an extensive sampling regime of sediment, pore water and worms from seven sites with different levels of contamination across the UK. Worms were fed and maintained under ambient conditions in a flow-through seawater system and sampled at 3, 6 and 9 months. Using BCR sequential extraction, bioavailable metal concentrations in the sediment were assessed in addition to pore water and tissues metal concentrations. The induction of metallothionein (MT) activity, especially at month 6, revealed the detoxification potential of N. virens under metal stress conditions. Significant correlations were obtained between copper bioavailable concentrations in the sediment and MT levels at month 3 and between zinc bioavailable concentrations in the sediment and MT levels at month 6. The highest DNA damage was recorded at month 3 for high copper & zinc combined treatment with 36.44%. Significant correlations were obtained between sediment bioavailable metal concentrations and DNA damage. In addition, the study of metal induced gene expression will reveal for the first time metal regulation process in the polychaete N. virens. This study showed that (1) not only high copper was toxic to N. virens but high copper & zinc combined treatment was the most toxic to the worms and (2) MT and DNA damage were sensitive and reliable endpoints used to evaluate copper and zinc toxicity. [less ▲]

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See detailEvidence of a fine-scale genetic structure for the endangered Pyrenean desman (Galemys pyrenaicus) in the French Pyrenees
Gillet, François ULg; Cabria Garrido, Maria Teresa; Blanc, Frédéric et al

Poster (2014, December)

The Pyrenean desman (Galemys pyrenaicus) is a small semi-aquatic mammal endemic to the Pyrenean Mountains and the northern half of the Iberian Peninsula where it lives in mountain streams of cold and well ... [more ▼]

The Pyrenean desman (Galemys pyrenaicus) is a small semi-aquatic mammal endemic to the Pyrenean Mountains and the northern half of the Iberian Peninsula where it lives in mountain streams of cold and well-oxygenated flowing waters (Nores et al. 2007). This species is currently considered as vulnerable in the IUCN Red List (Fernandes et al. 2008) and has been suffering from habitat loss and fragmentation for decades, inevitably impacting its distribution. The ecology and biology of this species are poorly known, notably because of its elusive behavior and its primarily nocturnal activity (Stone 1987, Bertrand 1994). Its distribution area is even not definitively established. Furthermore, a recent genetic study, based on mitochondrial and intronic sequences (Igea et al. 2013), showed that the genetic variability of the Pyrenean desman is very low in the Pyrenees. In this study we investigated the potential existence of a genetic structure and gene flow at a smaller scale using 24 polymorphic microsatellites loci. As the Pyrenean desman is a very elusive species, we completed our sample collection of tissues with faeces samples coming from the French distribution area of this species. Doing so, we successfully identify 70 individuals out of 355 faeces samples. Bayesian analyses revealed a cryptic genetic structure in our data set. Three clusters were evidenced (one western, one central and one eastern) and gene flow appears to be limited between these clusters (min. Fst value of 0.2). [less ▲]

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See detailPoster session 5: Friday 5 December 2014, 14:00-18:00Location: Poster area.
Henri, C.; DULGHERU, Raluca Elena ULg; Magne, J. et al

Poster (2014, December)

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See detailENSO forecast using a wavelet-based mode decomposition
Deliège, Adrien ULg; Nicolay, Samuel ULg; Fettweis, Xavier ULg

Poster (2014, December)

We introduce a new method for forecasting major El Niño/ La Niña events based on a wavelet mode decomposition. This methodology allows us to approximate the ENSO time series with a superposition of three ... [more ▼]

We introduce a new method for forecasting major El Niño/ La Niña events based on a wavelet mode decomposition. This methodology allows us to approximate the ENSO time series with a superposition of three periodic signals corresponding to periods of about 31, 43 and 61 months respectively with time-varying amplitudes. This pseudo-periodic approximation is then extrapolated to give forecasts. While this last one only resolves the large variations in the ENSO time series, three years hindcast as retroactive prediction allows to recover most of the El Niño/ La Niña events of the last 60 years. [less ▲]

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See detailIntentions d'implémentation et procrastination chez les étudiants.
Stassart, Céline ULg; Potdevin, Benoit; Etienne, Anne-Marie ULg

Poster (2014, December)

Introduction : La procrastination est définie comme une tendance à reporter ce qui est nécessaire pour atteindre un objectif. Ainsi, la procrastination concerne une intention qui ne se traduit pas en ... [more ▼]

Introduction : La procrastination est définie comme une tendance à reporter ce qui est nécessaire pour atteindre un objectif. Ainsi, la procrastination concerne une intention qui ne se traduit pas en action. L’intention d’implémentation se définit notamment à travers le désengagement face au problème, l’orientation vers les buts, et l’activation des ressources et cette étude examine la part explicative de ces trois dimensions dans le processus de procrastination. Méthodologie : Un échantillon de 197 étudiants ont complété les versions françaises du Solution Focused Inventory (SFI), et du Procrastination Assessment Scale for Students (PASS). Résultats : L’intention d’implémentation intervient dans 32% de la variance de la procrastination. Le désengagement face au problème et l’orientation vers les buts expliquent de manière significative la fréquence de procrastination.  Conclusion : Le processus de procrastination pourrait en partie être expliqué par manque d’intentions d’implémentation, plus particulièrement par une difficulté à se désengager du problème (tendance à être bloqué dans sa réflexion en se focalisant davantage sur les problèmes) et à s’orienter vers les buts (présenter des difficultés à mettre au point des plans d’action efficaces). [less ▲]

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See detailPoster session 3: Thursday 4 December 2014, 14:00-18:00Location: Poster area.
Gabriels, C.; LANCELLOTTI, Patrizio ULg; Van De Bruaene, A. et al

Poster (2014, December)

Detailed reference viewed: 13 (5 ULg)
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See detailPoster session 4: Friday 5 December 2014, 08:30-12:30Location: Poster area.
Uejima, T.; Itatani, K.; Nakatani, S. et al

Poster (2014, December)

Detailed reference viewed: 11 (2 ULg)
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See detailWood digestion in lower termites: multidisciplinary approaches based on differential feeding
Bauwens, Julien ULg; Brasseur, Catherine ULg; Tarayre, Cédric ULg et al

Poster (2014, December)

Termites digestive tract and hindgut especially still holds many secrets despites hundreds of years of research. The complexity of the symbiotic microbial community and the contrast of physio-chemical ... [more ▼]

Termites digestive tract and hindgut especially still holds many secrets despites hundreds of years of research. The complexity of the symbiotic microbial community and the contrast of physio-chemical environments found in lower termites paunch are potentially the key point to explain the efficiency of ligno-cellulose digestion. Contribution of advancing technologies accelerates the progress of our knowledge in this field. Here, we present multiple approaches combining old and recent techniques used to highlight the effect of ligno-cellulosic compounds on termite gut and the role of populations from the symbiotic microbial community. Termites Reticulitermes flavipes (Kollar) submitted to various artificial diets showed variations in flagellates populations profile and enzymatic activities. Differential protein expression was investigated using 2D-DIGE MALDI-TOF-TOF and 2D-LC-MS/MS using high resolution orbitrap analyzer. Results from both proteomic experiments tend to support each-other and bring complementary points of view. The gel-free analysis resulted in highly contrasted identification of enzymes involved in ligno-cellulose digestion and metabolism. Finally, differential feeding experiments leaded to in vivo selection of different symbiotic communities. These communities were characterized following some metabolism assays and allowed the cultivation of diverse microbial consortia using media closely related to the respective artificial diets. This work provides relevant data on termite and associated microbial community response to alimentary diets. [less ▲]

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See detailIN UTERO INFECTION BY SCHMALLENBERG VIRUS INDUCES ARTHROGRYPOSIS MULTIPLEXA CONGENITA IN OVINE FETUSES
Boseret, Geraldine; Claine, Francoise; Coupeau, Damien et al

Poster (2014, December)

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See detailValidation d’un questionnaire d’ergonomie cognitive relatif au travail chez des patients atteints de sclerose en plaques
Blavier, Adelaïde ULg; DELRUE, Gaël ULg; HENNEN, Julie et al

Poster (2014, December)

We present datas validating the use of our QUIPSEP questionnaire among multiple sclerosis patients actually employed.

Detailed reference viewed: 45 (6 ULg)
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See detailImpact of triclosan on behaviour and neural development of Cyprinodon variegatus
Benichou, Farida; Rahmouni, Chahrazed; Denoël, Mathieu ULg et al

Poster (2014, December)

The study focussed on the effects of triclosan (TCS) exposure on mobility and hearing capacities of Cyprinodon variegatus larvae. TCS is an omnipresent antimicrobial and contaminant of aquatic ecosystems ... [more ▼]

The study focussed on the effects of triclosan (TCS) exposure on mobility and hearing capacities of Cyprinodon variegatus larvae. TCS is an omnipresent antimicrobial and contaminant of aquatic ecosystems, which can act as endocrine disruptor, mainly by modifying thyroid functioning. Larval stages are particularly vulnerable to deleterious effects of endocrine disrupters because of potential impairment of fish development and behaviour. Exposure to TCS was conducted at fertilization of eggs at concentrations likely to be found in the environment: 20, 50 and 100 μg.l-1. The analysis of growth parameters of C. variegatus showed no effect of TCS on the fertility of eggs, survival and larval weight. Subsequently, THs concentrations were measured on 15 days post hatching larvae. THs are initially produced as T4 (thyroxine) cells and then converted in the bioactive form of T3 (triiodothyronine) cells. The observed increase of T4 and T3 cells in larvae exposed to 50 and 100 μg.l-1 suggests an increase in THs synthesis as a consequence of TCS exposure. Auditory thresholds of larvae were determined using ABR (Auditory Brainstem Response) technique, and finally larval mobility was measured. For both parameters no significant differences were observed among the three different treatments. Audiograms showed that the auditory system is not yet completely established at 30 days post hatching. However, these results allowed us to consider C. variegatus as an “hearing generalist” because this species have a hearing sensitivity lower than 2000 Hz. Regarding locomotion, our result summarized short time experiences targeting only swimming speed, distance and degree of mobility. It would be interesting to expand the behavioural aspects on other parameters of locomotion and integrate Cyprinodon reaction to different stress (light or touch). In conclusion, our results require an extensive long-term study on the full life cycle of C. variegatus, in order to evaluate the impact of triclosan on neural function and behaviour through several generations. [less ▲]

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See detailRecherche de sensations, sexualité et pornographie à l’adolescence
Puglia, Rosa ULg; Glowacz, Fabienne ULg

Poster (2014, December)

Introduction : L’adolescence est une période tumultueuse caractérisée par des transformations d’ordre physique, psychologique, cognitive et sociale ainsi que par des conduites exploratoires et de ... [more ▼]

Introduction : L’adolescence est une période tumultueuse caractérisée par des transformations d’ordre physique, psychologique, cognitive et sociale ainsi que par des conduites exploratoires et de recherche de sensations dans lesquelles la consommation de pornographie peut prendre part. L’exposition à la pornographie durant l’adolescence peut s’inscrire dans ce processus développemental avec le risque d’influencer les conduites sexuelles du jeune. Cette thématique peut, dès lors, susciter de nombreuses questions. Méthodologie : Notre recherche, réalisée sur une population d’adolescents âgé entre 15 et 19 ans (N=319), vise à analyser les conduites de consommation de pornographie (motivations, représentations et comportements) en lien avec la recherche de sensations, une dimension prégnante à l’adolescence. Plus particulièrement, nous avons analysé les motivations de ces jeunes à visionner des images et films à caractère pornographique et ce qui les amène à arrêter. Nous nous sommes, également, interrogés quant à l’influence de la consommation pornographique au niveau du développement psycho-sexuel et des pratiques sexuelles de ces jeunes. Pour ce faire, nous avons administré à ces jeunes un questionnaire comprenant, en plus des items se rapportant à la sexualité et la pornographie, plusieurs tests évaluant des dimensions du fonctionnement psychologique et social (test de solitude, recherche de sensation, relations aux pairs, délinquance auto-révélée,... ). Résultats : Nos résultats indiquent qu’une majorité des adolescents ont déjà visionné de la pornographie. L’intérêt pour ce média ainsi que son usage augmente avec l’âge, atteint son apogée vers 16-17 ans puis diminue. Cette tendance curvilinéaire se retrouve également dans les conduites exploratoires telles que les conduites déviantes et la recherche de sensations, ce qui nous amène à envisager une désistance spontanée de la consommation de pornographie en fin d’adolescence. Conclusions : Ces résultats montrent l’importance de comprendre la consommation de pornographie dans un processus développemental et nous amène à envisager une désistance spontanée de cette conduite en fin d’adolescence. [less ▲]

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See detailMRI myocardial perfusion, a reliable alternative to FFR
GHEKIERE, Olivier; DEWILDE, W; HOA, D et al

Poster (2014, December)

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See detailClub 35 Poster session 2: Thursday 4 December 2014, 08:30-18:00Location: Poster area.
Voilliot, D.; Magne, Jm; DULGHERU, Raluca Elena ULg et al

Poster (2014, December)

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See detailGrossesses prolongées et risques psycho-médicaux
Halin, Stéphanie; Emonts, Patrick ULg; Fohn, Bruno et al

Poster (2014, December)

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See detailTaxonomic sufficiency for soft-bottom macrozoobenthos long term study - A case study in corsica
Donnay, Annick ULg; Pelaprat, Corinne; Lejeune, Pierre et al

Poster (2014, December)

Nowadays, the knowledge of the marine ecological quality status of an environment is essential and soft-bottom macrobenthos is one of the indicators used. Studies of soft-bottom macrobenthos are time ... [more ▼]

Nowadays, the knowledge of the marine ecological quality status of an environment is essential and soft-bottom macrobenthos is one of the indicators used. Studies of soft-bottom macrobenthos are time consuming and need expertise for organisms’ identification. Simplifications of these studies are tried and Taxonomic Sufficiency (TS) proposed by Ellis (1985) is one of research axes. For example, some studies highlight that family level identification could be sufficient to identify perturbed area (e.g: Bacci et al., 2009; De-La-Ossa-Carretero et al., 2012; Forde et al., 2013). Nevertheless, identification at species level could be recommended to have more precise information about the existing situation (Ajmal Khan, 2006) or to complete information from others levels (Conde et al., 2013). In Corsican waters where human impacts are less important than in main land waters, we present TS based on STARESO research studies between 2006 and 2012. This work is within the frameworks of the STARE-CAPMED program dedicated to STAtion of Reference and rEsearch on Change of local and global Anthropogenic Pressures on Mediterranean Ecosystem Drifts. After Permanova analysis and Canonical analysis of principal coordinates, eight habitat types have been identified along Corsican coastal water. Their own reference conditions and ecological class boundaries have been evaluated. Those reference conditions and ecological status have been identified for species, genus and family level. A highly significant correlation of calculated values between species and genus levels (R²=0.93) has been determined and a significant correlation between species and family level (R²=0.75). Genus and family levels have a significant Spearman correlation with species level (p<0.05). An application of these reference conditions on the macrobenthos assemblages sampling on 14 stations in spring 2011 and late summer 2012 in Calvi Bay highlights areas with high, good or moderate ecological status. In conclusion, family level is sufficient to follow spatial and/or temporal ecological status. [less ▲]

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See detailPoster session 6: Saturday 6 December 2014, 08:30-12:30Location: Poster area.
Henri, C.; DULGHERU, Raluca Elena ULg; Magne, J. et al

Poster (2014, December)

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See detailFatigue et auto-évaluation chez des patients atteints de sclérose en plaques
DELRUE, Gaël ULg; Blavier, Adelaïde ULg; HENNEN, Julie et al

Poster (2014, December)

Different fatigue scales specific for multiple sclerosis patients correlate quite differently with other psychological measures which gives rise to a necessary reflexion about the tools used in clinical ... [more ▼]

Different fatigue scales specific for multiple sclerosis patients correlate quite differently with other psychological measures which gives rise to a necessary reflexion about the tools used in clinical practice and their meanings. [less ▲]

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See detailEffect of tree species mixture on earthworm communities on a continental scale
De Wandeler, Hans; Baeten, Lander; Carnol, Monique ULg et al

Poster (2014, December)

The belowground food web represents a major part of associated biodiversity in forest ecosystems, and plays a significant role in the ecosystem processes of litter decomposition and nutrient turnover ... [more ▼]

The belowground food web represents a major part of associated biodiversity in forest ecosystems, and plays a significant role in the ecosystem processes of litter decomposition and nutrient turnover. Past research has demonstrated overwhelming evidence of strong tree species identity effects on earthworm communities. It has been proposed that increased plant community diversity would be beneficial to the abundance and diversity of the belowground food web, but effects of tree species diversity on earthworm communities have seldom been reported, and are inconclusive. In this study at continental scale we evaluated whether tree species diversity positively affects earthworm biomass and diversity. For this purpose the FunDivEUROPE Exploratory Platform was used with 209 plots in 6 regions well spread over Europe with a low within-region site variability, but a within-region tree species diversity gradient from monocultures to 3 or 4 species plots. In every plot earthworms were sampled using a combined method of mustard extraction and hand sorting of litter and a soil monolith. Data are being analysed with multivariate tools and mixed effects models. First results suggest only limited influence of tree diversity on the biomass of earthworm communities at continental scale. Tree diversity effects are weak, context specific and interacting with tree identity. In nutrient poor soils we found a negative tree diversity effect on earthworm biomass when deciduous monocultures are enriched with coniferous species, while in rich soils we found a positive tree diversity effect which could be related with the food security this provides to the earthworm community. [less ▲]

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See detailGenetic structure of nase, Chondrostoma nasus, and common barbel, Barbus barbus (Teleostei, Cyprinidae) populations in South Belgium rivers: toward a rational management of conservation restocking
Gennotte, Vincent ULg; Michaux, Johan ULg; Prignon, Christian ULg et al

Poster (2014, December)

Nase (Chondrostoma nasus) and common barbel (Barbus barbus) are two rheophilic cyprinid fish naturally present in the Belgian Meuse and Rhine basins. During the last decades, the construction of dams ... [more ▼]

Nase (Chondrostoma nasus) and common barbel (Barbus barbus) are two rheophilic cyprinid fish naturally present in the Belgian Meuse and Rhine basins. During the last decades, the construction of dams together with changes in hydrological regimes, modifications of riverbed morphology and water pollution have caused some local dramatic declines in their populations. However, recent improvements in terms of water quality and habitat fragmentation allow considering as realistic a rational restocking plan of locally endangered patrimonial fish species such as nase and common barbel. Restocking operations for a conservation purpose have to be based on the knowledge and the use of wild type genetic strains. Therefore, the aim of this study was to characterize the genetic structure and diversity of nase and common barbel populations in South Belgium rivers. Wild common barbels (n = 313) and nases (n = 271) were sampled by electrofishing in respectively 10 and 6 different tributaries from the Meuse and Rhine rivers. Genotyping was performed on 24 microsatellite markers for each species. Preliminary results showed, for both species, a differential genetic clustering between fish originating from the Meuse basin and those originating from the Rhine basin. Detailed analysis describing the genetic structure and diversity of South Belgium populations will be presented and will serve as a management tool to set up a breeding plan for conservation restocking. [less ▲]

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See detailEcological diversity of damselfishes (Pomacentridae) from Moorea
Gajdzik, Laura ULg; Parmentier, Eric ULg; Lepoint, Gilles ULg et al

Poster (2014, December)

The Pomacentridae (damselfishes) represents the 3rd most species-rich coral reef fish family, including 394 species spread worldwide. Recent studies suggested that damselfishes iteratively evolve along ... [more ▼]

The Pomacentridae (damselfishes) represents the 3rd most species-rich coral reef fish family, including 394 species spread worldwide. Recent studies suggested that damselfishes iteratively evolve along three main trophic guilds: “the pelagic feeders” feeding mainly on zooplankton, “the benthic feeders” grazing filamentous algae or biting coral polyps, and an “intermediate” group with species feeding on zooplankton, small benthic invertebrates and algae in variable proportions. Comparing the ecological diversity of damselfish communities among various geographical regions could assess such an iterative radiation. Within this context, the present study is a first attempt exploring the trophic diversity of damselfish community at Moorea Island (French Polynesia). The relationship between the trophic guilds, their habitat diversity and their behavior is evaluated. Habitat and behaviour of 16 damselfish species were described during transects along which different kinds of data were collected. For examples, the location within the reef (e.g. fringing or barrier reef), the depth, the substrate over which fishes are living or the solitary/gregarious habits were recorded. Diet of individuals was investigated by means of stomach content and stable isotopes analyses. Correlations between the dietary preferences and ecological data (habitat and behaviour) are given and the ecological diversity among trophic groups is compared. [less ▲]

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See detailThe effects of Triclosan on the metabolism of developing Sheepshead minnow (Cyprinodon variegatus) larvae
Lallemand, Lise; Voisin, Anne-Sophie; Darchambeau, François ULg et al

Poster (2014, December)

The aquatic environment represents the final sink for many chemicals, including bactericidal agents. Among them Triclosan (TCS) has been shown to affect the thyroid system of teleost. Thyroid hormones are ... [more ▼]

The aquatic environment represents the final sink for many chemicals, including bactericidal agents. Among them Triclosan (TCS) has been shown to affect the thyroid system of teleost. Thyroid hormones are involved in the control of metabolism, so changes in hormone levels induced by triclosan may affect respiratory rates and antioxidant stress in exposed fish. Couples of three females and two males were placed in breeding chambers designed for this experiment. Eggs were collected and maintained in seawater. Embryos were selected under a dissection microscope, randomly assigned to each of five treatment groups: Control, DMSO control, 20 μg/L TCS, 50 μg/L TCS and 100 μg/L TCS and placed in incubation dishes (50 per dish) at 25°C. On day 6, embryos hatched and larvae were transferred to 1L dishes. The larvae were fed on artemias and on flaked fish food till day 15 and 30 post hatching when the fish were analyzed. Respiratory rate measurements were carried out by respirometry and assays of antioxidant enzymes, Glutathionreductase (GR), glutathione peroxidase (GPx) and glutathione-S-transferase (GST) were conducted to determine the presence of oxidative stress. Respirometry showed that TCS exposed fish exhibited decreased the metabolism at 15 dph, whereas no differences in respiration rate could be observed between control and exposed larvae at 30 dph. At 15 dph no difference was observed for any of the antioxidant enzymes, whereas at 30 dph a sharp increase in the activity of GR was observed between the control and TCS exposed fish. The activity of GST and Gpx remained stable. Thyroid hormones are major factors controlling the metabolic rate related to respiration and oxidative stress. TCS reduced the metabolism at 15 dph that corresponds to the moment where larvae to juvenile transition of Sheepshead minnows occur. Previous experiments showed that TCS induces an increase in thyroid hormone concentrations and hyperthyroidism induces oxidative stress. So our observed increase of antioxidant protection mechanisms could be a way to compensate oxidative stress. On the other hand, the changes in GR activity observed at 30 dph, may also be related to the reduced metabolism at 15 dph. [less ▲]

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See detailPREDICTION OF SHORT-TERM OUTCOME IN PREGNANT WOMEN WITH SUSPECTED PREECLAMPSIA: THE PROGNOSIS STUDY
Zeisler, Harald; Llurba, Elisa; CHANTRAINE, Frédéric ULg et al

Poster (2014, December)

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See detailMagnetic Reconnection During Major Magnetospheric Storms
Hubert, Benoît ULg; Milan, S.E.; Cowley, S.W.H.

Poster (2014, December)

We combine imaging of the proton aurora from the SI12-IMAGE instrument with ionospheric convection measurement from the SuperDARN radar network to analyze the cycle of magnetic flux opening and closure of ... [more ▼]

We combine imaging of the proton aurora from the SI12-IMAGE instrument with ionospheric convection measurement from the SuperDARN radar network to analyze the cycle of magnetic flux opening and closure of the Earth magnetosphere. Interaction between the solar wind and the Earth geomagnetic environment causes a reconfiguration of the magnetic field that connects the interplanetary magnetic field (IMF) to the geomagnetic field. This reconnection process produces open magnetic field lines (i.e. field lines of the magnetosphere that close through the interplanetary medium) that are dragged to the magnetotail by the solar wind flow, where they eventually reconnect again, back to a closed topology. The SI12 imaging of the Doppler-shifted Lyman-α emission of the proton aurora is used to estimate the location of the boundary separating open and closed field lines at ionospheric altitude. We then estimate the open magnetic flux of the Earth magnetosphere, encircled by this boundary. The rate of reconnection causing a variation of the open magnetic flux can be expressed as a voltage in application of Faraday’s law. This voltage is measured along the open/closed field line boundary determined from the imaging data. The electric field associated with the voltage has two origins: motion of the boundary and the ionospheric field. We use the ionospheric electric field deduced from ionospheric convection measurement from the SuperDARN to estimate the reconnection voltage at the magnetopause (flux opening) and in the magnetotail (flux closure) accounting for the motion of the open/closed field line boundary determined from the SI12 images. The method is applied during several (strong) geomagnetic storms. These intervals are characterized by large values of open flux and reconnection rates, as a result of coupling between the solar wind and the geomagnetic environment. We present these results in terms of a magnetospheric mode that develops under strong coupling with the solar wind, a condition known to be prone to the development of sawtooth events, characterized by overloading of the magnetosphere with open magnetic flux. [less ▲]

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See detailDiscontinuité des liens et souffrance psychique : quelles stratégies adaptatives en situation de précarité sociale ?
Glowacz, Fabienne ULg; Spitz, Jacqueline

Poster (2014, December)

Dans un contexte social en mutation prônant l’autonomie de l’individu, le passage à l’âge adulte pour les jeunes en situation de vulnérabilité économique sociale et relationnelle se révèle un véritable ... [more ▼]

Dans un contexte social en mutation prônant l’autonomie de l’individu, le passage à l’âge adulte pour les jeunes en situation de vulnérabilité économique sociale et relationnelle se révèle un véritable défi. L’objectif de l’étude est de comprendre les ressources et les conduites adaptatives de ces jeunes leur permettant de faire face à la souffrance psychique que génère la discontinuité des liens, et d’éviter la désaffiliation sociale et l’errance. Cette recherche clinique de terrain s’inscrit dans une approche ethno-psychologique par sa méthode. Elle s’appuie sur les récits de 6 jeunes adultes âgés entre 19 et 25 ans rencontrés dans le cadre d’un hébergement temporaire en maison d’accueil. Chaque récit est séquencé et analysé selon plusieurs niveaux : les indicateurs sociologiques du passage à l’âge adulte, les modes de relations des individus au niveau familial et social, les indicateurs de précarité. Le parcours de ces jeunes adultes en situation de précarité sociale, cumulant vulnérabilité relationnelle et vulnérabilité économique, les amène à développer des conduites qui leur permettent à la fois de préserver le lien avec autrui, de s’adapter à l’environnement et de préserver une maîtrise d’une affiliation anxiogène. Leur vécu expérientiel de rupture et de perte continue à s’actualiser dans une nécessaire oscillation entre rapprochement et distanciation, en résonnance avec leur style d’attachement primaire. Conclusion « Etablir le lien sur un mode discontinu » apparait comme un mode d’adaptation à l’environnement à la fois protecteur de leur intégrité psychique et fragilisant leur socialisation. [less ▲]

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See detailImpact of shading on meiofauna in a Posidonia oceanica meadow
Pete, Dorothée ULg; Gobert, Sylvie ULg

Poster (2014, December)

Posidonia oceanica meadow is an endemic ecosystem of the Mediterranean coasts. A known threat to this ecosystem is aquaculture. In zones of intensive fish production, P. oceanica meadow tends to be less ... [more ▼]

Posidonia oceanica meadow is an endemic ecosystem of the Mediterranean coasts. A known threat to this ecosystem is aquaculture. In zones of intensive fish production, P. oceanica meadow tends to be less healthy or to disappear .One of the reasons for this is a decrease in the light that reaches the leaves (direct shading, increase of water turbidity or of epiphytic algae density). Unfortunately, when the meadow begins to die, it is often too late to act. So, people are trying to find indicators that react early to this kind of perturbations. In this framework, this study focuses on the impact of shading (without nutrient enrichment) on the meiofauna living in the surface sediment of a P. oceanica meadow. An in situ shading experiment was led from the end of May to the end of August 2009, at a depth of 10 m, in a reference P. oceanica meadow. Three shading nets were put in the meadow to reach a light extinction of 50%. A control site was also defined. The first two centimetres of sampled sediment cores were studied. After three months of shading, the total abundance of meiofauna at the shading site was lower than at the beginning of the experiment, while it stayed around the same level at the control site. This difference is mainly due to a decrease in the total number of foraminiferans, nematods, gnathostomulids, copepods and bivalves. However, no significant difference in diversity was observed. At the end of this experiment, it appeared that, contrarily to what is mostly said in the literature, the direct organic enrichment that occurs at fish farms is not the only reason to the modification of the meiofauna communities of the ecosystem. The shading by itself has also an effect. [less ▲]

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