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See detailEvaluation des risques de compaction des sols en Région wallonne
Rosiere, Charlotte ULg; Verbrugge, Jean-Claude; Destain, Marie-France ULg

Poster (2010, November 24)

Le projet de directive européenne COM(2006)232 établit un cadre général pour la protection des sols. Le projet prévoit que les états membres identifient les zones susceptibles d’être touchées par des ... [more ▼]

Le projet de directive européenne COM(2006)232 établit un cadre général pour la protection des sols. Le projet prévoit que les états membres identifient les zones susceptibles d’être touchées par des processus de dégradation (érosion, compaction, salinisation, …) et qu’ils proposent des mesures afin de réduire les risques. La compaction peut affecter la macroporosité, les mouvements de l’eau et de l’air dans le sol, les mécanismes de croissance racinaire, le développement de la faune du sol. De ce fait, elle est donc souvent à l’origine d’une diminution du rendement des cultures. En Région wallonne, les machines destinées à la récolte de betteraves risquent d’engendrer une compaction du sol car elles sont souvent utilisées alors que le sol est humide et que les charges à l’essieu sont importantes. Les machines d’exploitation forestière présentent également des risques pour la compaction du sol. La contrainte de préconsolidation (Pc) est considérée comme la valeur à ne pas dépasser pour éviter que le sol subisse des dégâts difficilement réversibles. Si les contraintes appliquées sont supérieures à Pc, le sol garde un comportement élastique (état réversible) et il n’y a pas de modification dans l’organisation de la porosité du sol. Par contre, si les contraintes appliquées sont supérieures à Pc, le sol entre en plasticité et ses fonctions naturelles sont perturbées. Dans un premier temps, des cartes de sensibilité du sol à la compaction sont élaborées. Elles évaluent la contrainte de préconsolidation des sols de la Région wallonne, au moyen des fonctions de pédotransfert (FPT) de Lebert et Fleige (2003). L’impact des engins sur le sol est étudié au niveau du ‘subsoil’, sous la couche de labour, là où le sol ne peut pas être régénéré par des outils classiques de travail du sol. Les paramètres des FPT sont accessibles au sein de Aardewerk ou sont trouvés dans la littérature. Les valeurs de Pc sont classées selon 6 niveaux de sensibilité, à deux états hydriques différents. Dans un deuxième temps, la distribution des contraintes verticales générées par le passage d’engins ‘types’, caractérisés par les dimensions des pneus, la charge à l’essieu et la pression de gonflage, est calculée à l’aide du logiciel Soilflex. Les Pc du sol sont alors comparées aux contraintes verticales induites par les engins, pour aboutir à des cartes de risque de compaction. Celles-ci simulent 4 scénarios : deux teneurs en eau et deux types d’engins. Afin de valider ces deux types de cartes, des tests oedométriques destinés à mesurer Pc sont réalisés sur des sols agricoles et forestiers. Pour faciliter la démarche et calculer les FPT de Lebert et Fleige avec une plus faible incertitude, il serait utile que la CNSW comporte des données relatives aux fractions granulométriques, à la matière organique des sols, la cohésion, l’angle de frottement interne, la masse volumique apparente sèche de sol, … [less ▲]

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See detailSensitivity of simulated surface wetness duration to meteorological variations in three different regions of Grand-Duchy of Luxembourg
Mahtour, Abdeslam ULg; El Jarroudi, Moussa ULg; Hoffmann, Lucien et al

Poster (2010, November 23)

Surface wetness duration (SWD) is an important factor influencing the occurrence of winter wheat diseases. For this reason, SWD is extremely important for the management of crop protection activities. In ... [more ▼]

Surface wetness duration (SWD) is an important factor influencing the occurrence of winter wheat diseases. For this reason, SWD is extremely important for the management of crop protection activities. In order to understand the SWD variability and its influence on winter wheat disease, the objective of this study was to (i) determine the sensitivity of our model on varying input plant parameters and (ii) to evaluate the influence of simulated SWD to meteorological variations in three different climatic regions of the Grand-Duchy of Luxembourg (EVERLANGE, OBERCORN and SCHIMPACH). In this work, an agrometeorological model known as the Surface Wetness Energy Balance (SWEB) was applied for the simulation of SWD. The model was previously applied in another study for winter wheat cultivars and was adapted for use with agrometeorological data easily available from standard meteorological monitoring stations. Based on weather data and simulated SWD data, sensitivity analyses were performed to compare the effects of relative humidity, air temperature, wind speed and net radiation on wetness duration over one growing season (March-July) at three test sites. The results indicated that the sensitivities were very similar at three sites and there was no spatial trend (i.e. difference between locations) in the sensitivities. However, the model is most sensitive to relative humidity and differences between 0.5 and 25 h (per month) SWD were found when increasing/decreasing relative humidity by 10%. The model was least sensitive to changes in air temperature, showing differences of only 0.5–2 h (per month) in SWD. Intermediate sensitivity is found for rainfall, net radiation and wind speed. Among the input plant parameters values, SWD was most sensitive to the maximum fraction of canopy allowed as wet surface area, leaf area index, maximum water storage per unit area and least sensitive to crop height. The sensitivity to parameter values was less important compared to the sensitivity to the meteorological variable relative humidity. [less ▲]

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See detailSensitivity of simulated surface wetness duration to meteorological variations in three different regions of the Grand-Duchy of Luxembourg
Mahtour, Abdeslam; El Jarroudi, Moussa ULg; Hoffmann, Lucien et al

Poster (2010, November 22)

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See detailA fountain of droplets
Terwagne, Denis ULg; Delon, Giles ULg; Adami, Nicolas ULg et al

Poster (2010, November 21)

A vessel is plunged upside down into a pool of 50 cSt silicone oil. An air bell is then created. This bell is vertically shaken at 60 Hz that leads to the oscillation of the air/oil interface. The edges ... [more ▼]

A vessel is plunged upside down into a pool of 50 cSt silicone oil. An air bell is then created. This bell is vertically shaken at 60 Hz that leads to the oscillation of the air/oil interface. The edges of the immersed vessel generate surface waves that propagate towards the center of the bell. When the amplitude of the oscillation increases, wave amplitude increases. We study the influence of the angle between successive sides on the wave patterns. Two kinds of vessel have been studied: a triangular and a square prism. The shape of the air/oil meniscus depends on the angle between the sides of the considered prism. As the amplitude of the oscillation is increased, the triple line, which is the contact line between the solid and the air/oil interface, moves up and down. Above a given acceleration that depends on the immersion depth and on the shape vessel, wave goes under the corner edge of the bell. During the oscillation, the wave generates at the edges presents a singularity that leads eventually to a jet and a drop ejection. A drop is ejected at each oscillation. More complicated ejection can be produced with further increase of the amplitude. This is a sample arXiv article illustrating the use of fluid dynamics videos. [less ▲]

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See detailFrozen Splash
Delon, Giles ULg; Terwagne, Denis ULg; Adami, Nicolas ULg et al

Poster (2010, November 21)

We have studied the splashing dynamics of water drops impacting granular layers. Depending on the drop kinetic energy, various shapes are observed for the resulting craters. Experimental parameters that ... [more ▼]

We have studied the splashing dynamics of water drops impacting granular layers. Depending on the drop kinetic energy, various shapes are observed for the resulting craters. Experimental parameters that have been considered are : the size of the millimetric droplets ; the height of the free fall, ranging from 1.5 cm to 100 cm ; and, the diam- eter of the grain. As the drop is impacting the sand layer, energy is dissipated and a splash of sand occurs. Meanwhile, surface tension, in- ertia and viscosity compete, leading to strong deformations of the drop which depend on the experimental conditions. Just after the drop en- ters into contact with the sand, imbibition takes place and increases the apparent viscosity of the fluid. The drop motion is stopped by this phenomenon. Images and fast-video recordings of the impact allowed to find scaling laws for the crater morphology and size. <br />This abstract is related to a fluid dynamics video for the APS DFD gallery of fluid motion 2010. [less ▲]

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See detailProjet thérapeutique n°99 "Personnes âgées"
Squelard, Gilles ULg; Vilain, Anne; Jacob, Bernard

Poster (2010, November 19)

ès avril 2011, la fonction de concertation fera l’objet d’un financement structurel pour les soins en santé mentale en Belgique. Cette fonction va se construire en partie sur base de l’expérience des ... [more ▼]

ès avril 2011, la fonction de concertation fera l’objet d’un financement structurel pour les soins en santé mentale en Belgique. Cette fonction va se construire en partie sur base de l’expérience des projets thérapeutiques « réseaux et circuits de soins ». Ces recherches actions se concrétisent par l’organisation de réunions de concertation pluridisciplinaires autour de situations chroniques et complexes. Plus spécifiquement, le projet thérapeutique n°99 « personnes âgées » a pour objectifs de favoriser le maintien à domicile de personnes âgées, de garantir la continuité des soins et du projet de vie, d’améliorer la qualité de la réintégration au domicile, d’éviter les réhospitalisations, de mieux cerner les conditions d’une réhospitalisation, et d’aborder les problématiques d’isolement, de solitude, voire de maltraitance. Objectif Communication de recommandations concernant l’organisation de réunions de concertation et la participation des intervenants sur base de l’expérience du projet thérapeutique n°99 « Personnes âgées » en Province de Liège. Méthodologie Le projet thérapeutique n°99 vise les personnes âgées de 65 ans et plus, habitant en Province de Liège et présentant une pathologie psychiatrique spécifique : démence, abus d’alcool, abus d’opiacés, abus d’hypnotiques, anxiolytiques ou sédatifs, schizophrénie, ou trouble schizo-affectif. Le projet repose sur une démarche empirique. Il consiste en l’organisation de réunions de concertation pluridisciplinaires autour de patients et de leur famille dont la finalité est la mise en place d’un suivi individualisé. Résultats L’âge moyen de la population suivie est de 79,21 ± 6.71. Elle se constitue majoritairement d’hommes (51%). Les diagnostiques les plus fréquents à l’inclusion sont la démence (Alzheimer, vasculaire,..) et l’abus d’alcool. Pour chaque situation, un agent de suivi est choisi. Son rôle sera de rester en contact avec l’usager et de faire le lien avec les différents intervenants. C’est également à lui que revient l’organisation des réunions de concertation. Cette tâche demande de tenir compte des emplois du temps des différents professionnels concernés. Les médecins sont des intervenants essentiels mais parfois difficile à mobiliser pour une réunion d’une heure. Le projet 99 arrive à des résultats satisfaisants quant à la participation des médecins tant d’un point de vue quantitatif que qualitatif. Nous avons pu dégager des pratiques facilitant leur participation en réunion de concertation. Enfin, l’agent de suivi est le garant de la place laissée à chacun pour s’exprimer lors de la réunion et en particulier à l’usager/famille. Des recommandations ont également pu être formulées à ce sujet. Discussion/conclusion L’expérience du projet thérapeutique n°99 s’est avérée extrêmement fructueuse, par l’atteinte des objectifs centrés sur l’usager et leur famille, mais également à travers les nombreux échanges interprofessionnels. La concertation pluridisciplinaire s’est avérée être un excellent moyen de découverte des partenaires, en amenant une représentation plus concrète de leur offre de soins et de leur mode de fonctionnement. [less ▲]

Detailed reference viewed: 82 (15 ULg)
Peer Reviewed
See detailA mathematical model of calcium ion influence on the activity of osteogenic cells
Carlier, Aurélie ULg; Chai, Yoke Chin; Theys, Tina et al

Poster (2010, November 19)

Detailed reference viewed: 21 (4 ULg)
Peer Reviewed
See detailGenital re-excretion of Murid gammaherpesvirus 4 following intranasal infection
François, Sylvie ULg; Vidick, Sarah ULg; Sarlet, Michaël ULg et al

Poster (2010, November 18)

Gammaherpesviruses are the archetypes of persistent viruses that have been identified in a range of animals from mice to man. They are host-range specific and establish persistent, productive infections ... [more ▼]

Gammaherpesviruses are the archetypes of persistent viruses that have been identified in a range of animals from mice to man. They are host-range specific and establish persistent, productive infections of immunocompetent hosts. Thus, infected individuals simultaneously both elicit antiviral protective immune response and secrete infectious virions. The best studied gammaherpesviruses are Human herpesvirus 4 and Human herpesvirus 8. As these viruses have no well-established in vivo infection model, related animal gammaherpesviruses are an important source of information. We are studying Murid herpesvirus 4 (MuHV-4), a virus that has originally been isolated from bank voles (Myodes glareolus). Although MuHV-4 has not been isolated from house mice (Mus musculus), infection of inbred laboratory mouse strains is commonly accepted as a good model for studying gammaherpesviruses in vivo. To date, it has however never been possible to monitor viral reexcretion and virus transmission in this species suggesting that this model could be imperfect. In order to identify potential re-excretion sites, intranasally infected mice were followed through global luciferase imaging for up to six months after infection. By this technique, we were able to detect appearance of viral replication in mice genital tract at various times post-infection. Typically, it firstly occurred between days 20 to 30 after infection, a period at which it is admitted that latency is established. Ex vivo imaging, quantitative PCR and immunohistochemistry helped us to determine that virus genomes were present in high quantity in the vaginal tissue and that viral replication occurred mainly at the vaginal external border. Finally, we highlighted the presence of free infectious viruses in the vaginal cavity at the moment of the observation of viral replication. In conclusion, we experimentally indentified for the first time a reexcretion site for MuHV-4 in mice that had been intranasaly infected. It therefore suggests potential genital transmission, either horizontal or vertical, of this virus in mice populations. In the future, these results could help us to better understand the biology of gammaherpesviruses but should also allow us to develop vaccinal strategies that could prevent the spread of these viruses in natural populations. [less ▲]

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See detailAuditory forebrain activation in the female canary is modulated by male song quality.
Barker, Jennifer ULg; Monbureau, Marie; Leboucher, Gerard et al

Poster (2010, November 17)

One of the chief functions of birdsong is to attract and stimulate females. In canaries (Serinus canaria), specific phrases (“A” phrases) sung by males have been identified as especially attractive for ... [more ▼]

One of the chief functions of birdsong is to attract and stimulate females. In canaries (Serinus canaria), specific phrases (“A” phrases) sung by males have been identified as especially attractive for females. These phrases unite a number of characteristics that are particularly difficult to combine, including large frequency bandwidth, high repetition rate and multiple-note syllables. Females exposed to “A” phrases produce more copulation displays and deposit more testosterone into their eggs. However, the neuroendocrine pathway underlying the translation of song audition to changes in testosterone deposition in yolks is not understood. Increased expression of several immediate early genes including c-fos and zenk (also called egr-1 in mammals) in other songbird species has been observed in the auditory forebrain of females hearing attractive song, and such differential activation may represent a first step in signal processing linking auditory input to egg testosterone deposition. Female canaries in breeding condition were exposed to 60 minutes of “sexy” song with a preponderance of “A” phrases, “non-sexy” song lacking “A” phrases, or white noise. Thirty minutes after the end of song playback, brains were collected, fixed in acrolein and sectioned and stained by immunohistochemistry for quantification of the Fos protein, an indicator of neuronal activity, in several regions involved in audition and auditory processing. The endocrine condition of each female was determined by measuring ovarian and oviduct weight at the time of autopsy. In the caudomedial mesopallium (CMM), Fos expression was higher in females that had heard sexy song than those that heard non-sexy song or white noise. Expression of Fos in the caudomedial nidopallium (NCM), the nucleus spiriformis medialis (SPM), the nucleus ovoidalis (OV), and the song nucleus HVC was unaffected by song quality. Thus differential auditory processing in the CMM may be an initial stage in the assessment by a female of song information to differential testosterone deposition in the egg. [less ▲]

Detailed reference viewed: 27 (2 ULg)
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See detailBinding properties of clozapine and related compounds on native D2 dopamine receptors in normal and oxidative medium
Liégeois, Jean-François ULg; Dilly, Sébastien ULg

Poster (2010, November 16)

Despite the presence of several side effects, clozapine remains a valuable drug in treating schizophrenia. The presence of haematological toxicity was proposed to be related to the formation of nitrenium ... [more ▼]

Despite the presence of several side effects, clozapine remains a valuable drug in treating schizophrenia. The presence of haematological toxicity was proposed to be related to the formation of nitrenium species (1). Indeed, nitrogen derivatives like clozapine or olanzapine are very sensitive to oxidation while oxygen or sulphur isosteres such as loxapine, clothiapine and JL13, possess a very low sensitivity to oxidation (2-4). In the present study, we explore the impact of oxidation conditions on the binding of these drugs on native rat dopamine D2 receptors. Rats brains were quickly removed after cerebral dislocation and dissected on ice to get striata. After weighting, tissues were homogenized in buffer and washed three times by centrifugation. The final pellet was dispersed in the appropriate volume of incubation buffer (Tris 50 mM, MgCl2 5 mM, EDTA (Na2) 1 mM buffered at pH 7.4 with 4N HCl) depending on the experimental conditions. In oxidative conditions, horseradish peroxidase (1.25 µg/tube) and H2O2 (50 µM) were added to the incubation buffer. [3H]-Spiperone was used as radioligand and the non specific binding was determined in the presence of haloperidol (10 µM). Incubation temperature and time were 27°C and 60 min respectively. Competition experiments were done with different molecules such as haloperidol and various tricyclic derivatives. In our previous studies (2,3), we had observed that compounds like clozapine or olanzapine are significantly affected by oxidative conditions. In the present report, we show that this sensitivity is also associated with a dramatic decrease of binding affinity. Unlike such diazepine analogues, the binding of loxapine and JL13, two oxygen isosteres is slightly affected in oxidative conditions. Firstly, these results show that the distal nitrogen is not affected by the oxidative conditions. Secondly, the nitrenium formation (1) might lead to a tridimensional change that would reduce the interactions in the binding pocket. The oxidative effect of HRP/H2O2 mixture can be prevented by addition of ascorbic acid to the incubation medium. Thus depending on the oxidant character of the extracellular medium in physiological or pathophysiological conditions, interaction of molecules with different targets can be modified significantly. [less ▲]

Detailed reference viewed: 35 (2 ULg)
See detailInfluence of brain-derived neurotrophic factor val66met human polymorphism on declarative memory consolidation
Mascetti, Laura ULg; Foret, Ariane ULg; Matarazzo, Luca et al

Poster (2010, November 15)

The Brain-Derived Neurotrophic Factor (BDNF) is a neurotrophin which in the adult brain regulates long-term potentiation. In humans, valine (val) to methionine (met) substitution in the 5’ pro-region of ... [more ▼]

The Brain-Derived Neurotrophic Factor (BDNF) is a neurotrophin which in the adult brain regulates long-term potentiation. In humans, valine (val) to methionine (met) substitution in the 5’ pro-region of the BDNF protein is associated with poorer episodic memory. Neurons transfected with met-BDNF-Green Fluorescence Protein showed lower depolarization-induced secretion, while constitutive secretion is unchanged. Here, we hypothesized that the differences in BDNF release determined by this polymorphism would influence memory consolidation and that in comparison with the val/met (=val/met or met/met), val/val individuals would show higher memory performance and different brain responses during a 16h-delayed rather than immediate retrieval session. Participants encoded a series of neutral faces in the afternoon. Retrieval sessions took place one hour after the encoding session, and in the following morning, during the acquisition of functional Magnetic Resonance Imaging (fMRI) time series with a 3 Tesla Allegra scanner. During retrieval, studied faces and new ones were presented in random order. For each stimulus, the subjects indicated whether they could retrieve the encoding episode with (“Remember”), or without details (“Know”), or if they thought the item had not been presented during encoding (“New”). A repeated-measure ANOVA on discrimination index (d’) showed significant effects of group (F(1, 27)=8.65, p=0.007, n(val/val)=14, n(val/met)=15) and session (F(1, 27)=24.64, p=0.000), although the group by session interaction was not significant (F(1, 27)=1.29, p=0.267). fMRI results showed a significant genotype (val/val > val/met) by session (delayed > immediate retrieval) by memory type (Remember > Know) interaction in the right inferior occipital gyrus (x=42, y=-78, z=0, p=0.004, Z=3.77), the left inferior parietal lobule (x=-56, y=-40, z=48, p=0.013, Z=3.43), the posterior cingulate cortex (x=14, y=-42, z=42, p=0.019, Z=3.29) and the right hippocampus (x=28, y=-22, z=-22, p=0.03, Z=3.11). Val/val individuals demonstrate higher memory performance than met-carriers but the change in memory performance between immediate and delayed retests is similar in both allelic groups. In contrast, neural correlates of recollection change between sessions differently according to genotype: responses increase significantly more in val/val than in val/met individuals in brain areas involved in the retrieval, accumulation and binding of perceptual memory details during delayed, relative to immediate retest. These data suggest that activity-dependent BDNF release promotes memory consolidation during the first post-training hours. [less ▲]

Detailed reference viewed: 53 (14 ULg)
See detailNeural correlates of cognitive control at the item level in the Stroop task.
Grandjean, Julien ULg; D'Ostilio, Kevin ULg; Fias, Wim et al

Poster (2010, November 15)

Detailed reference viewed: 25 (1 ULg)
See detailGestion des zones d'activité économique existantes. Gestion parcimonieuse du sol et mixité raisonnée des fonctions
Girolimetto, F.; Labeeuw, F.-L.; Lambotte, Jean-Marc ULg et al

Poster (2010, November 08)

Detailed reference viewed: 24 (1 ULg)
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See detailL'agame papillon géant, Leiolepis guttata (Cuvier, 1829), adapté à l'herbivorie, se nourrit-il également d'insectes ?
Tran, Tinh ULg; Rochette, Anne-Julie; De Martynoff, Abigail et al

Poster (2010, November 06)

Detailed reference viewed: 33 (5 ULg)
See detailL'entomologie forensique: c'est quoi?
Frederickx, Christine ULg; Dekeirsschieter, Jessica ULg; Haubruge, Eric ULg

Poster (2010, November 06)

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See detailAMYLOLYSIN, A LANTIBIOTIC PRODUCED BY BACILLUS AMYLOLIQUEFACIENS GA1.
Arguelles Arias, Anthony ULg

Poster (2010, November 05)

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See detailInterests of using a regional model to forecast wind power production
Doutreloup, Sébastien ULg

Poster (2010, November 05)

European policies have decided to reduce the greenhouse gas emissions of 20% and to reach 20% of renewable power production by 2020. Increasing wind power is one of the numerous solutions to reach these ... [more ▼]

European policies have decided to reduce the greenhouse gas emissions of 20% and to reach 20% of renewable power production by 2020. Increasing wind power is one of the numerous solutions to reach these goals. However, this kind of energy production depends on the meteorological conditions and gives it an intermittent behaviour. The wind speed variations cause voltage and frequency fluctuations that are unacceptable for the power grid. Therefore, forecasting production will become essential with the aim of integrating this kind of energy production into the power grid. We have developed and compared two forecasting models which give as outputs the wind power production every 15 minutes over the Belgian territory: the first one uses the outputs from the global model GFS (available at a horizontal resolution of 0.5° every 3h) and the second one uses the regional climate model WRF-NMM (using a horizontal resolution of 4km). Both of these models predict the wind speed and transform wind speed into wind power production, using a power curve which depends on the wind turbines and their characteristics. The first model using the GFS outputs is not precise enough in space and time to correctly forecast the wind speed in punctual wind farms. That is why we apply some specific tunings on these forecasts. These tunings depend on the air density, the wind direction and the stability of the air mass. The second model using the WRF-NMM outputs runs over the Belgian territory. Initial conditions are forced by the GFS outputs at 0.5° and WRF computes a physical based spatio-temporal downscaling of the meteorological variables. The outputs have a spatial resolution of 4 km and a time resolution of 15 minutes. Some tunings are also needed to adjust the wind power forecasts by comparison to the wind power observations. We present here some results of both models and the interest of using a regional model for more precise wind power forecasting. [less ▲]

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Peer Reviewed
See detailHigh resolution modelling of the Greenland ice sheet surface mass balance using the regional climate model MAR coupled with a downscaling interface
Franco, Bruno ULg; Fettweis, Xavier ULg; Erpicum, Michel ULg

Poster (2010, November 05)

We are developing a coupling interface downscaling the 25km-atmosphere fields simulated by the regional climate MAR (Modèle Atmosphérique Régional) model onto a 5km-grid in order to resolve the surface ... [more ▼]

We are developing a coupling interface downscaling the 25km-atmosphere fields simulated by the regional climate MAR (Modèle Atmosphérique Régional) model onto a 5km-grid in order to resolve the surface processes at high resolution with the SISVAT (Sea Ice Soil Vegetation Atmosphere Transfer) snow-ice module. This coupling interface improves the representation of the topography and ablation zone of the Greenland ice sheet (GrIS) in the MAR model, and therefore will provide higher resolution estimations of the GrIS surface mass balance (SMB) without additional computing time. By using outputs from previously-gauged global circulation models (GCM) as forcing fields, the MAR model coupled with the downscaling interface will then perform 5km future simulations of the GrIS SMB for different IPCC greenhouse gas emissions scenarios for the 21st century. [less ▲]

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Peer Reviewed
See detailSéchage convectif d’un milieux poreux humide. Obtention des coefficientS des echanges de surface
Kahlerras, Loubna ULg; Belhamri

Poster (2010, November 03)

Ce travail se propose d’analyser les phénomènes du séchage convectif d’un milieu poreux non saturé. Le modèle de calcul considère le couplage des équations de la couche limite et celles qui décrivent le ... [more ▼]

Ce travail se propose d’analyser les phénomènes du séchage convectif d’un milieu poreux non saturé. Le modèle de calcul considère le couplage des équations de la couche limite et celles qui décrivent le transfert de chaleur et de masse dans un milieu poreux, ayant les caractéristiques du béton renforcé avec des coupeaux de bois. Pendant l'opération de séchage, beaucoup de problèmes sont produits comme consommation d'énergie élevée, cinétiques du séchage et le changement de la forme finale du produit. En fait l'amélioration de la technique du séchage devient une nécessité. Parmi les auteurs qui ont approché ce problème, nous pouvons citer les travaux de [1], [2], [3], [4], [5]. Le but est donc analysé le comportement hydrique du milieu poreux, montrer l’effets de la variabilité du coefficient d’échange massique sur le transfert de masse à l’intérieur du milieu poreux et aussi l’effet de certains paramètres pertinents du matériau comme l’humidité initiale, sur le processus du séchage. [less ▲]

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See detailFunctional and physicochemical properties of starches isolated from sorghum cultivars cultivated in algerian hyperarid regions
Boudries, Nadia; Sindic, Marianne ULg; Belhaneche, Naima et al

Poster (2010, November 03)

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See detailMolecular analysis of the FOLR genes in patients with cerebral folate deficiency
SEGERS, Karin ULg; Hanson, J; RAMAEKERS, Vincent ULg et al

Poster (2010, November 02)

Detailed reference viewed: 9 (0 ULg)
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Peer Reviewed
See detailNano-ultrasonics sensors
Arca, Ahmet; Dispas, Amandine ULg; Jamie, Twycross et al

Poster (2010, November)

Ultrasound is a powerful tool for diagnosing medical and mechanical problems. Conventional ultrasonics work at megahertz frequencies and with wavelengths of 1-2mms to 10’s mm. This means it cannot "see ... [more ▼]

Ultrasound is a powerful tool for diagnosing medical and mechanical problems. Conventional ultrasonics work at megahertz frequencies and with wavelengths of 1-2mms to 10’s mm. This means it cannot "see" very small objects at the nanoscale. Our new transducers are so small it is impractical to communicate with them electrically. Instead we have devised a non contact method of talking to them using short pulses of laser light. We have adopted two approaches for producing these transducers, one method builds plates devices the other uses self assembled nanoparticles. The transducers are made from alternating metal and soft transparent layers. They have optical and mechanical resonances and so the devices have to be made such that they work well both mechanically and optically [less ▲]

Detailed reference viewed: 166 (3 ULg)
See detailKisspeptin in the developing and adult rat brain
Desroziers, Elodie ULg; Mikkelsen, Jens; Caraty, Alain et al

Poster (2010, November)

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See detailChronologie de l’architecture médiévale et datation par luminescence : étude de l’église St-Irénée de Lyon (France)
Bouvier, Armel; Guibert, Pierre; Blain, Sophie ULg et al

Poster (2010, November)

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See detailEvolution des structures de sols sous itinéraires techniques contrastés : relation entre courbes de rétention et analyse par microtomographie aux rayons X
Beckers, Eléonore ULg; Roisin, Christian; Léonard, Angélique ULg et al

Poster (2010, November)

Tillage reduction seems to affect porosity distribution, orientation and connectivity. Soil samples were removed from plots under conventional tillage or reduced tillage. Their water retention curves were ... [more ▼]

Tillage reduction seems to affect porosity distribution, orientation and connectivity. Soil samples were removed from plots under conventional tillage or reduced tillage. Their water retention curves were measured, and the characterization of soils porosity was made using x-ray microtomography measurements. Results show differences in the meso as well as in the macroporosity. [less ▲]

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See detailAffine Warp Propagation for Fast Simultaneous Modelling and Tracking of Articulated Objects
Declercq, Arnaud ULg

Poster (2010, November)

We propose a new framework that allows simultaneous modelling and tracking of articulated objects in real time. We introduce a non-probabilistic graphical model and a new type of message that propagates ... [more ▼]

We propose a new framework that allows simultaneous modelling and tracking of articulated objects in real time. We introduce a non-probabilistic graphical model and a new type of message that propagates explicit motion information for realignment of feature constellations across frames. These messages are weighted according to the rigidity of the relations between the source and destination features. We also present a method for learning these weights as well as the spatial relations between connected feature points, automatically identifying deformable and rigid object parts. Our method is extremely fast and allows simultaneous learning and tracking of nonrigid models containing hundreds of feature points with negligible computational overhead. [less ▲]

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See detailRaman spectroscopic study of complex formation between major calixarene derivatives and three pharmaceutical substances
Tiuca, Ioana; Mantanus, Jérôme ULg; Iacob, Bogdan et al

Poster (2010, November)

Complex formation of six calix[n]arene derivatives – tert-butyl-calix[4]arene (C4), tert-butyl-calix[6]arene (C6), tert-butyl-calix[8]arene (C8) and their ethyl-acetic-ester derivatives (C4Es4, C6Es6 ... [more ▼]

Complex formation of six calix[n]arene derivatives – tert-butyl-calix[4]arene (C4), tert-butyl-calix[6]arene (C6), tert-butyl-calix[8]arene (C8) and their ethyl-acetic-ester derivatives (C4Es4, C6Es6, C8Es8) – has been the subject for our Raman spectroscopic study. Substances taken in study for complexation were the two widely used anticoagulants – warfarin and its 5-nitro- derivative, acenocoumarol – and their antidote, phytomenadione (also known as phylloquinone or vitamin K1). For each standard substance, Raman spectra were studied between 3620 and 90 cm-1. In order to obtain the complexes, a mixture of solutions of each calixarene and each analyte was prepared, in a stoichiometric ratio of 1:1 and then the solvents were evaporated. Spectra of solid residues obtained were compared with those of initial molecules. In all cases, there was observed a Raman band shifting or even the disappearance of some bands, indicating that calixarene derivatives interact with the studied molecules. In conclusion, the six calixarene derivatives taken in study seem to be able to form complexes with the molecules of warfarin, acenocoumarol and phylloquinone. [less ▲]

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See detailThe Tibetan Singing Bowl
Terwagne, Denis ULg; Bush, John

Poster (2010, November)

The Tibetan singing bowl is a type of standing bell. Originating from Himalayan fire cults as early as the 5th century BC, they have since been used in religious ceremonies, for shamanic journeying, exor ... [more ▼]

The Tibetan singing bowl is a type of standing bell. Originating from Himalayan fire cults as early as the 5th century BC, they have since been used in religious ceremonies, for shamanic journeying, exor- cism, meditation and shakra adjustment. A singing bowl is played by striking or rubbing its rim with a wooden or leather-wrapped mallet. The sides and rim of the bowl then vibrate to produce a rich sound. When the bowl is filled with water, this excitation can cause crispa- tion of the water surface that can be followed by more complicated surface wave patterns and ultimately the creation of droplets. We here demonstrate the means by which the Tibetan singing bowl can levi- tate droplets. This is a sample arXiv article illustrating the use of fluid dynamics videos. [less ▲]

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See detailSexually differentiated cell proliferation in the medial preoptic nucleus of Japanese quail
Mouriec, Karen ULg; Bardet, Sylvia; Balthazart, Jacques ULg

Poster (2010, November)

The androgen-depend sequence of male copulatory behaviors is sexually differentiated in Japanese quail like in many other vertebrates. This behavior disappears within a week after castration of males and ... [more ▼]

The androgen-depend sequence of male copulatory behaviors is sexually differentiated in Japanese quail like in many other vertebrates. This behavior disappears within a week after castration of males and is rapidly restored following treatment with testosterone. In contrast, ovariectomized females treated with testosterone never show these behaviors. This sex-specific responsiveness to testosterone results from organizational effects of embryonic ovarian estrogens. The behavioral phenotype of male and female quail is completely reversed by treatment, before embryonic day 12 (E12), of male embryos with estrogens or of female embryos with an inhibitor of aromatase, the enzyme converting testosterone into estradiol. In the quail brain, the medial preoptic nucleus (POM) is a necessary and sufficient site for the activation of sexual behavior by testosterone. It can be identified by a dense population of aromatase-immunoreactive neurons and, importantly, aromatase activity in this region is sexually differentiated (males>females) and this difference is maintained even when birds are treated with a same dose of testosterone. Aromatase is thus, like sexual behavior, a sex-specific feature regulated by testosterone in adult quail and presumably organized in early life by steroid action. The cellular basis of these organizational processes have not been identified. We analyzed the ontogeny of POM cells by injecting 5-bromo-2-deoxyuridine (BrdU) in eggs at different embryonic (E) stages (E8, E10, E12, E14 and E16) and quantifying BrdU-labeled cells at postnatal (PN) day 56. Large numbers of BrdU-positive cells were observed throughout the POM of males and females injected on E8-E10 but most cells were post-mitotic in both sexes on E14-E16. E12 injections resulted in a larger number of BrdU cells in females than in males at PN56. However, male and female embryos injected on E12 and killed on E13, PN1 or PN15 had similar numbers of BrdU positive cells. Furthermore, BrdU injections on E14 labeled very few cells at PN 56 suggesting that the POM is essentially post-mitotic at that age. Together these data suggest that a sex-specific apoptosis must occur between PN15 and PN56. Double-label immunohistochemistry for BrdU and for the neuron-specific marker Hu indicated that BrdU-positive cells born between E8 and E16 are not neurons and are thus presumably glial cells. This sex-specific cell proliferation occurring around the end of the critical period of sexual differentiation may have an important impact on brain and behavior differentiation. The phenotype of these cells and the mechanisms mediating their differential development are currently under investigation. [less ▲]

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See detailMicro-catchments classification: a tool for mud flow mitigation
Degre, Aurore ULg; Mokadem, Abdel Ilah; Cordonnier, Hélène et al

Poster (2010, November)

Hydrologic similarities between catchments can be of use in the context of overland flood and mud flow hazards management. In Wallonia, upstream micro-catchments were mapped for each runoff concentration ... [more ▼]

Hydrologic similarities between catchments can be of use in the context of overland flood and mud flow hazards management. In Wallonia, upstream micro-catchments were mapped for each runoff concentration axis. The outlets of these catchments are considered at the point where water reaches the permanent river stream. No less than 145 547 micro catchments were mapped in Wallonia (16900 km²). Their area varies between 1 and 1233 ha (mean area: 7.8 ha). A data base was built up to synthesize their major characteristics like e.g. area, shape and mean slope. No clear classification appeared. At this stage, it became obvious that the major components of these catchments had to be handled simultaneously from a hydrological point of view in order to produce a clear classification. The main hydrologic significant data are available in Wallonia: the digital soil map at 1/20 000 scale, the DTM (raster file of 10 meters resolution), digital land use at 1/10 000 scale and spatial statistics for rain (IDF curves for each commune). A hydrologic model was developed using the python programming language in the ArcGis 9.3 environment. This model is based on the NRCS – USDA method. Rain abstraction is calculated on the basis of a CN (curve number) which integrates the soil type, the land use and the slope. Water transfer is computed using a convolution based on triangular unit hydrogrammes. This calculation includes the concentration time which integrates the catchment morphology (shape and slope) and the land use (roughness). The MUSLE equation is also computed in order to handle the sediment problem. The results consist in a full project hydrograph, peak flow value, flood water volume and sediment quantification in response to a project rainfall. The CN and MUSLE semi-empirical methods are validated at larger scale in Wallonia but have still to demonstrate their efficiency at the micro-catchment scale. Nevertheless, the aforementioned variables can be considered as integration factors of the whole hydrological context of the micro-catchments. It allows us to build advice on overland flow and mud flow mitigation at watershed scale. This approach can also be of help to compare ungauged micro-catchments between each other and possibly transpose the soil conservation practices from a site to another. [less ▲]

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See detailFine Mapping of a large-effect QTL for scab resistance co-localising with the major gene RVI6 (Vf).
Verdu, Cindy ULg; Lasserre, Pauline; Durel, Charles-Eric

Poster (2010, November)

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See detailA percepção da expressão físico-motora por professors do ensino basico
do Couto, Joao; Cloes, Marc ULg; Sequeira, Pedro

Poster (2010, November)

This poster proposes the findings of a study aiming to identify the representations of elementary school classroom teachers about physical education.

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See detailSynthesis of core cross-linked micelles for the development of new drug delivery systems
Cajot, Sébastien ULg; Danhier, F.; Lautram, N. et al

Poster (2010, October 29)

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See detailKashin-Beck Disease: evaluation of mineral intake in young Tibetan children from endemic areas
DERMIENCE, Michael ULg; Maesen, Philippe ULg; Mathieu, Françoise et al

Poster (2010, October 26)

Kashin-Beck disease is an endemic and chronic osteochondropathy. This disease principally occurs in the Tibet Autonomous Region and in several provinces of the People’s Republic of China. Although many ... [more ▼]

Kashin-Beck disease is an endemic and chronic osteochondropathy. This disease principally occurs in the Tibet Autonomous Region and in several provinces of the People’s Republic of China. Although many studies have already been conducted and many others are still underway, its ethiology remains unknown. A multifactorial hypothesis has been proposed: selenium deficiency, high concentration of organic matters in drinking water (fulvic acids) and mycotoxin poisoning by fungi infecting cereals. This original study aimed to measure the mineral contents of the food most often consumed in severe endemic regions and then to evaluate the daily intake of minerals in young Tibetan children from endemic areas. The mineral elements were selected in relation to their implications in bone metabolism. A sampling campaign split up into two time periods (winter and spring) was carried out. Ten families from two distinct regions were selected based on three criteria: they live in endemic areas; they include a 3 to 5 year-old child; this child has a KBD brother or sister. At the same time, a nutritional survey was made by the means of a prospective questionnaire in order to list the 24h food intake of the 3 to 5 year-old child. This survey highlighted the extremely monotonous cereal-based Tibetan diet. An analytical method for the minerals was developed as follows: mineralization of samples performed by microwave-assisted wet process; mineralized solutions measured by several atomic absorption or emission spectrometric methods and molecular absorption spectrometric methods. The analytical method was validated by mean of certified reference materials. Mean food contents were calculated and compared to food composition reference tables. High iron contents and selenium deficiencies were highlighted in several foods. Daily intakes were estimated combining mineral measurements and nutritional survey results. These were compared to dietary reference intakes from reference tables. This estimation reveals some crucial points: we confirm a marked deficiency in calcium; Ca/P ratios are always low; iron and copper intakes are excessive; zinc is the most probably deficient; while selenium could be deficient; manganese intakes often exceed toxicity thresholds. Nevertheless, this study encounters some limits. The bioavailability of minerals is a critical point that deserves further investigations. Moreover, a larger study over a longer term covering both endemic and non-endemic regions is required for definite conclusions to be reached. [less ▲]

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See detailAdaptive reflective processes using the IMS-LD specification
Verpoorten, Dominique ULg; Kelle, S

Poster (2010, October 26)

The research work presented in this poster coins a new range of reflection support tools called "REFLECTION AMPLIFIERS", viz. deliberate and well-considered prompting approaches that offer learners ... [more ▼]

The research work presented in this poster coins a new range of reflection support tools called "REFLECTION AMPLIFIERS", viz. deliberate and well-considered prompting approaches that offer learners structured opportunities to examine and evaluate their own learning. [less ▲]

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See detailInterest of routine dosage of meropenem in difficult to treat infections
Frippiat, Frédéric ULg; Bensahi, Ilham; Denooz, Raphael ULg et al

Poster (2010, October 23)

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See detailImpact of grazing by amphipods on the epiphytic cover of the Posidonia oceanica leaves: an in situ experiment.
Michel, Loïc ULg; Dupont, Alessandra; Gobert, Sylvie ULg et al

Poster (2010, October 22)

It is now established that several species of amphipods associated to Mediterranean Posidonia oceanica meadows consume the macro-epiphytes present on the leaves of the seagrass. Moreover, under controlled ... [more ▼]

It is now established that several species of amphipods associated to Mediterranean Posidonia oceanica meadows consume the macro-epiphytes present on the leaves of the seagrass. Moreover, under controlled in vitro conditions, three amphipod taxa (Apherusa chiereghinii,Dexamine spiniventris and Gammarus spp.) are able to drastically deplete the biomass of erected algae, thus influencing the epiphytic cover in both a quantitative and a qualitative way. Here, we tried to assess whether this strong and complex trophic interaction was realized in the field. We designed an in situ experiment that used microcosms placed directly in the meadow, at a depth of 10m, to estimate the impact of grazing by the aforementioned amphipod taxa on the dynamics of the epiphytic cover. Both Gammarus spp. and Dexamine spiniventris caused a significant decrease of the biomass of erected algae and erected animals (bryozoans and hydrozoans). Impact of grazing by Apherusa chiereghinii on these two epiphytic groups was less important, although strong but marginally non-significant (0,1>p>0,05) trends to lower biomasses were present. None of the considered taxa seemed to consume encrusting macro-epiphytes. In addition, assimilation of epiphyte-derived carbon and nitrogen by grazers was monitored using stable isotopes (13C and 15N), and epiphyte elemental content (C & N) was measured. Our results shed light on trophic interactions between the amphipods from Posidonia oceanica meadows and the seagrass epiphytic cover, and thus enhance our understanding of the role of these grazers in the functioning of the meadow as an ecosystem. [less ▲]

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See detailSPATIO-TEMPORAL LOCALIZATION OF BETA TUBULIN III IN THE ORGAN OF CORTI AND IN THE SPIRAL GANGLIA BETWEEN THE EMBRYONIC DAY (E18) AND THE POST-NATAL DAY (P25) IN RAT.
Johnen, Nicolas ULg; Thelen, Nicolas ULg; Cloes, Marie ULg et al

Poster (2010, October 22)

The mammalian auditory organ, the organ of Corti (OC), is composed of mechanosensory hair cells and nonsensory supporting cell types. Based on their morphology and physiology, at least two types of ... [more ▼]

The mammalian auditory organ, the organ of Corti (OC), is composed of mechanosensory hair cells and nonsensory supporting cell types. Based on their morphology and physiology, at least two types of sensory cells can be identified in the OC: inner and outer hair cells. The structure of this organ is well reported in adult but its development is still little-known. By using confocal microscopy, we studied the spatial-temporal distribution of beta tubulin III during the differentiation of the OC in rat from the embryonic day 18 (E18) to the postnatal day (P25). The beta tubulin III is typical for neural cells in the OC. We observed that beta III tubulin is present in the extensions innerving the row of inner hair cells at E18. At E19, the extensions innerving the inner hair cells and the two first rows of outer hair cells were immunolabelled. From E21 to P25, all of hair cells were connected to the spiral ganglion. In the latter, the intensity of immunolabelling decreased between E18 to P25 and the labelling only concerned some cells. These results reveal that beta III tubulin appears before birth in the nervous extensions connecting the sensory cells of the OC according to a modiolar-to-striolar gradient. In the spiral ganglia, the labelling progressively decreases during its development. [less ▲]

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See detailThe role of meiofauna in energy transfer in a Mediterranean seagrass bed (Calvi, Corsica)
MASCART, THIBAUD; Lepoint, Gilles ULg; Borges, Alberto ULg et al

Poster (2010, October 22)

Meiofaunal communities of the endemic Mediterranean seagrass, Posidonia oceanica, were sampled in five different habitats characterised by different degradation level of macrophytodetritus. In term of ... [more ▼]

Meiofaunal communities of the endemic Mediterranean seagrass, Posidonia oceanica, were sampled in five different habitats characterised by different degradation level of macrophytodetritus. In term of abundance, harpacticoid copepods represent half of the community followed by nematodes and polychaetes. Two meiofauna communities were distinguished: (1) a benthic community of meiofauna, living in the sediment or on highly fragmented macrophytodetritus, and (2) a foliar, epiphytal community associated with seagrass leaves and low fragmented macrophytodetritus leaves. They differed significantly in their harpacticoid copepod family composition. The benthic community consisted mainly of families like Tisbidae and Miraciidae, while the epiphytal community was dominated by families like Thalestridae and Laophontidae. These differences in composition may also imply a differential functional diversity. Trophic biomarkers (stable isotopes, fatty acids) were used to identify the major sources of organic matter contributing to the copepods diet and hence to gain insight in the overall carbon flux. Harpacticoid copepods showed preferences to feed upon the epiphytal biofilm community composed of bacteria, diatoms, fungi and microalgae. Copepods used the seagrass and detritus material merely as substrate, but were attracted to the biofilm rather than the plant material which is rich in structural carbohydrates difficult to assimilate by animals (i.e. lignin, cellulose, ...). Since harpacticoid copepods showed to use different sources of carbon, unravelling the contribution of each of them and the role of the degradation level of the detritus for food selectivity is the next step forward. [less ▲]

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See detailLa sectorisation des cours d'eau wallons
Burton, Christophe ULg; Henrotay, Frédéric ULg; Borensztein, Aurélie ULg et al

Poster (2010, October 20)

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See detailUtilisation de la CNOSW en tant que carte d'occupation du sol dans le modèle EPICgrid
Sohier, Catherine ULg; Degre, Aurore ULg

Poster (2010, October 20)

Le modèle EPICgrid est un modèle hydrologique distribué de résolution 1km² couvrant toute la Wallonie. Il a été développé par Gx-ABT afin d’évaluer les flux d’eau, de nutriments et de sédiments vers les ... [more ▼]

Le modèle EPICgrid est un modèle hydrologique distribué de résolution 1km² couvrant toute la Wallonie. Il a été développé par Gx-ABT afin d’évaluer les flux d’eau, de nutriments et de sédiments vers les eaux de surface et vers les eaux souterraines. Il permet, entre autres, de tester l’impact de scénarios de gestion des nutriments sur la qualité des eaux en Région wallonne ainsi que des rapportages à différentes échelles dont les masses d’eau de surface. Le modèle requiert parmi ses données d’entrée une cartographie de l’occupation du sol. Dans un premier temps, la carte d'occupation des sols utilisée était issue du projet CARHY (Laime et Dautrebande, 1995) et reposait sur l'analyse d'images satellitaires Landsat pour refléter l’occupation du sol des années '90. En 2009, la CNOSW a été implémentée dans le modèle pour affiner spatialement et mettre à jour cette donnée en vue de simulations hydrologiques prospectives. Pour ce faire, les différentes classes de la CNOSW (niveau 5) ont été complétées au niveau des zones non cadastrées afin d’obtenir une couverture continue, hydrologiquement valide, de toute la Wallonie. Les classes ont ensuite été regroupées en classes hydrologiques d’occupation du sol (7 classes). La comparaison des cartes d’occupation du sol CARHY et issue de la CNOSW montre une répartition en classes similaire au niveau régional. Néanmoins, au niveau local, les différences marquées peuvent être constatées. Les zones urbaines sont également mieux représentées par la CNOSW. L’introduction de la CNOSW dans le modèle EPICgrid en apportant une spatialisation plus précise des occupations du sol a permis d’affiner les résultats du modèle et d’ouvrir de nouvelles pistes de développement telles que la représentation dans le modèle hydrologique du fonctionnement des bandes enherbées riveraines et inter-parcellaires. [less ▲]

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See detailProjet GISER - Elaboration d'un module de calcul des écoulements par la méthode SCS
Colard, François ULg; Mokadem, Abdel Ilah; Cordonnier, Hélène et al

Poster (2010, October 20)

Le projet GISER (gestion intégrée sol érosion ruissellement) consiste en différents axes de travail. Le poster présente un des outils opérationnels de calcul du ruissellement et des rendements en ... [more ▼]

Le projet GISER (gestion intégrée sol érosion ruissellement) consiste en différents axes de travail. Le poster présente un des outils opérationnels de calcul du ruissellement et des rendements en sédiments qui a été développé sur base des informations cartographiques existantes. Il utilise la carte d'occupation des sols mais également le MNT, la carte des sols, et les produits du projet ERRUISSOL. [less ▲]

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See detailBlock of SK channels by the sigma agonist 1,3-di-o-tolyl-guanidine: evidence for a novel site of action for SK blockers
Dilly, Sébastien ULg; Lamy, Cédric; Snyders, Dirk et al

Poster (2010, October 16)

Among ion channels involved in the control of neuronal activity, small conductance calcium-activated potassium channels (SK) represent an interesting therapeutic target. Indeed, they underlie medium ... [more ▼]

Among ion channels involved in the control of neuronal activity, small conductance calcium-activated potassium channels (SK) represent an interesting therapeutic target. Indeed, they underlie medium duration afterhyperpolarizations (mAHPs) in many types of neurons, thus inhibiting cell excitability. Three subtypes of SK subunits, SK1, SK2 and SK3, have been cloned and are expressed differentially within the central nervous system (CNS). Blocking SK channels might be beneficial in the treatment of several CNS disorders such as depression (SK3), Parkinson’s disease (SK3) and cognitive disorders (SK2). So far, the prototypical blocker of SK channels is apamin, an octadecapeptide from bee venom. We have recently shown that apamin blocks SK channels by binding to a site distinct from that used by classical pore blockers such as tetraethylammonium (TEA) (Lamy et al. J. Biol. Chem. 2010, 285, 27067-77). We have also demonstrated that the nonpeptide blocker N-methyl-laudanosine (NML) (Scuvée-Moreau et al. J. Pharmacol. Exp. Ther. 2002, 302, 1176-83) competes for the binding site of the toxin. Further, our research team has recently shown that the sigma agonist 1,3-di-o-tolyl-guanidine (DTG) directly blocks SK currents in a voltage-independent manner (Lamy et al. Eur. J. Pharmacol. 2010, 641, 23-8). We have combined patch clamp experiments on cell lines with molecular modelling and mutagenesis, to try to identify the site where DTG blocks. DTG was found to be equipotent on wild-type (WT) and apamin-insensitive (e.g. SK2H337N) channels. Moreover, mutated channels with increased sensitivity to TEA (SK3V520F: mean IC50 of TEA: 0.34 mM versus 11 mM for WT channels) were blocked by DTG with the same potency as WT channels. Thus, DTG does not seem to share the site of either apamin or TEA. Modelling data were in agreement with this possibility because of the identification of various potential binding sites. Although preliminary, these results suggest the existence of yet another binding site in the outer pore region of SK channels. [less ▲]

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See detailComparative toxicity of Deverra scoparia essential oil and blends of its major constituents against Tetranychus urticae Koch
Attia, Sabrine; Grissa, Kaouthar Lebdi; Lognay, Georges ULg et al

Poster (2010, October 14)

The phytophagous two-spotted spider mite Tetranychus urticae Koch is a ubiquitous species, present worlwide on a large variety of plant families. Since T. urticae resistance spread rapidly, biological ... [more ▼]

The phytophagous two-spotted spider mite Tetranychus urticae Koch is a ubiquitous species, present worlwide on a large variety of plant families. Since T. urticae resistance spread rapidly, biological control tactics are crucial to manage spider mite populations. In this respect, plant-derived essential oil products are a good alternative as they are, in general, considered as minimum-risk pesticides. In that context, laboratory experiments were conducted to assess the toxicity of essential oil of Deverra scoparia endemic plant to North Africa on females of the two spotted spider mite T. urticae (Koch). Essential oil was distillated from fresh leaves from D. scoparia and was sprayed on groups of adults females. The susceptibility of these females to D. scoparia essential oil was tested. A series of dilutions were used to bracket the dose-response range. Tests proved that female mortality increased with essential oil concentration with DL50 and DL90 values of 1.79 mg/l and 3.16 mg/l, respectively. The analysis of D. scoparia essential oil using GC-MS revealed presence of 10 major constituents: alpha-thujene, alpha-pinene, sabinene, myrcene, 3-carene, ocimene, terpinene-4-ol, pulegone, eugenol and beta-eudesmol. For a comprehensive evaluation of the potential of D. scoparia essential oil as acaricidal, individual blends activity of these constituents were tested against T. urticae female. Toxicity of blends of different components indicated significant differences among the active and inactive components, with the presence of all constituents necessary to have toxicity near to that of whole D. scoparia oil. The results showed that natural oil of D. scoparia and some of its constituents have potential for development as botanical acaricide, at least against T. urticae. [less ▲]

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See detailGeneration of camelid single-domain antibody fragments raised against proteins containing polyglutamine expansions
Pain, Coralie ULg; Scarafone, Natacha; Jaspar, Aurélie et al

Poster (2010, October 14)

Nine progressive neurodegenerative diseases are associated with the expansion of a polyglutamine (polyQ) tract above a threshold size (~ 35-45 residues) into nine different proteins [1]. These proteins ... [more ▼]

Nine progressive neurodegenerative diseases are associated with the expansion of a polyglutamine (polyQ) tract above a threshold size (~ 35-45 residues) into nine different proteins [1]. These proteins with expanded polyQ repeats have been found to form intranuclear amyloid-like aggregates, and the formation of these aggregates could play an important role in the pathogenesis [2-4]. The polyQ expansion is the only common feature among the proteins involved, suggesting it may be responsible for the aggregation phenomenon. Understanding the molecular mechanism by which the polyQ expansions promote aggregation is therefore crucial for the development of therapeutic strategies. The nine proteins associated with polyQ diseases are difficult to express recombinantly due to their big size and/or their insoluble character. In order to get further insights into the mechanism by which polyQ tracts promote aggregation, we have therefore decided to insert polyQ sequences into a well studied protein, the b-lactamase BlaP from B. licheniformis [5-6]. We have created chimeras containing 23, 30, 55, and 79 glutamines and we have investigated the effects of the insertions on the activity, the structure, the stability of BlaP as well as on its aggregating properties. Preliminary results indicate that BlaP is a good framework to study the molecular mechanism of aggregation associated with expanded polyglutamine tracts. On another hand, our previous work on the amyloidogenic variants of human lysozyme has shown that camelid single domain antibody fragments are very powerful structural probes to understand, at the molecular level, the mechanism of amyloid fibril formation [7]. Moreover, a recent study has suggested that expanded polyQ strectches adopt multiple conformations in solution that can be readily distinguished by monoclonal antibodies [8]. Altogether these results have encouraged us to generate VHHs against our different chimeras and we present here our preliminary results. References [1] Orr and Zoghbi (2007) Annu Rev Neurosci 30, 575-621. [2] DiFiglia et al. (1997) Science 277, 1990-1993. [3] Paulson HL (2000) Brain Pathol 10, 293-299. [4] Sanchez I. et al. (2003) Nature 421, 373-379. [5] Scarafone N. (2008) Mémoire de DEA en Sciences. Université de Liège. [6] Pain C. (2009) Mémoire de Master en Biochimie. Université de Liège. [7] Dumoulin et al. (2003) Nature 424, 783-788. [8] Legleiter J. et al. (2009) J Biol Chem 284, 21647-21648. [less ▲]

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See detailTowards the synthesis of mannose derivatives of natural phenolic compounds
Sainvitu, Pauline ULg; Nott, Katherine ULg; Richard, Gaetan ULg et al

Poster (2010, October 14)

The aim of this project is to graft a sugar moiety onto polyfunctional natural phenolic compounds. This should enhance their water solubility. The choice of an adequate sugar such as mannose could provide ... [more ▼]

The aim of this project is to graft a sugar moiety onto polyfunctional natural phenolic compounds. This should enhance their water solubility. The choice of an adequate sugar such as mannose could provide cellular recognition. The synthesis route was first tested on cinnamyl alcohol which is structurally close to the base pattern of natural phenolic compounds. <br />Two compounds are tested to catalyse the glycosilation between cinnamyl alcohol and D-mannose. The first one is an enzyme, the -glucosidase from almond, and the second one is a mineral acid catalyst immobilized on silica. Results show that -glucosidase is able to synthetize cinnamyl mannoside from mannose and cinnamyl alcohol. Furthermore, enzyme-catalyzed route lead to only one product and is so more specific than the chemical route where several products are observed. The obtaining of one product with a unique structure is interesting for the fundamental study of structure-function relationships (Interaction of the product with model membranes by Isothermal Titration Calorymetry and with the Langmuir Trough technique). In a future work, the reaction will be tested with more complex molecules (for example coniferyl alcohol). [less ▲]

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See detailUtilisation du jus de datte comme milieu d’immersion pour la déshydratation osmotique des graines de grenade
Bchir, Brahim ULg; Besbes, Souhail; Karoui, Romdhane et al

Poster (2010, October 14)

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See detailNew insights into the transformation of carbohydrates into platform chemicals
Richel, Aurore ULg; Wathelet, Jean-Paul ULg; Paquot, Michel ULg

Poster (2010, October 14)

The synthesis of furanic compounds from carbohydrates has become exciting in chemistry and in catalysis studies, because it represents one of the major routes for achieving sustainable energy supply and ... [more ▼]

The synthesis of furanic compounds from carbohydrates has become exciting in chemistry and in catalysis studies, because it represents one of the major routes for achieving sustainable energy supply and chemicals production.1 In particular, 5-hydroxymethylfurfural (5-HMF) and 2-furfural (2-F) occupy a pivotal place and are recognised as versatile and multi-functional starting points for the synthesis of a panel of precursors. Microwaves have readily appeared as a powerfull technique for accelerating reaction rates and increasing selectivities in the field of carbohydrate chemistry.3 In particular, their involvment in combination with heterogeneous catalysts have opened new vistas in the production of bio-oxygenated platform chemicals. The state of the art and main outlook of this strategy are reported here. [less ▲]

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See detailSynthèse assistée par Micro-ondes de dérivés d'acides uroniques
Laurent, Pascal ULg; Richel, Aurore ULg; Wathelet, Bernard ULg et al

Poster (2010, October 14)

At the moment, biorefining is increasingly seen as a promising alternative to petrochemical sector since it targets both the replacement of part of petroleum as a source of energy and the development of ... [more ▼]

At the moment, biorefining is increasingly seen as a promising alternative to petrochemical sector since it targets both the replacement of part of petroleum as a source of energy and the development of chemicals from the biomass, such as detergents, phytopharmaceutics, solvents, plastics, etc. The valorisation of carbohydrates arising from the hydrolysis of renewable feedstocks is therefore an area of outmost interest. In this context, uronic acids such as glucuronic acid (GlcA) or galacturonic acid (GalA) derived from widely available raw material such as hemicellulose or pectins represent important biocompatible and bioresorbable starting material. The quest of highly effective, environmentally friendly and straightforward chemical strategies to transform totally O-unprotected uronic acids into high valuable materials remains actually a particularly challenging task. A new strategy enabling the quantitative “one-pot” production of water-soluble monosubstituted D-glucofuranosidurono-6,3-lactones from unprotected D-glucuronic acid (D-GlcA) involving microwaves and an inexpensive siliceous-based promoter will be described. The use of a heterogeneous acid catalytic systems consisting of sulfuric acid impregnated onto silica (H2SO4/SiG60) or onto carbon (H2SO4/C), offers a green alternative to unrecyclable liquid sulfuric acid and permit the developpment of a truly eco-friendly green process, as these supported acids were readily separated from liquid products, without neutralization, by decantation or filtration, thus minimizing energy consumption and wastes. Faced with environmental concerns, this solventless methodology offers attractive features, including short reaction times, high yields and easy set-up and workup. [less ▲]

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See detailVolatile collection of cadaveric compounds
Dekeirsschieter, Jessica ULg; Verheggen, François ULg; Haubruge, Eric ULg

Poster (2010, October 14)

Thanatochemistry, also named ''chemistry of death'', is poorly studied and the available information regarding the volatile organic compounds (cadaveric VOCs) released after death are rather limited ... [more ▼]

Thanatochemistry, also named ''chemistry of death'', is poorly studied and the available information regarding the volatile organic compounds (cadaveric VOCs) released after death are rather limited. Thanks to the use of analytical chemistry methods ((TDS)GC-MS, GCxGC-TOF-MS), the olfactive signature of a dead body may be studied during the decomposition process. Different volatile collection techniques are used to study the smell of death. There are passive sampling techniques (Radiello® diffusive sampler) and dynamic sampling technique (pump device). The smell of death is constituted by a blend of hundreds of volatile organic compounds which change during the decay process. Main products detected are sulphur compounds such as sulphur dioxide, dimethyldisulfide and dimethyltrisulfide; alcools (1-butanol, 3-methyl-1-butanol), acids (butanoic acid, 2-methylbutanoic acid, 3-methylbutanoic acid and propanoic acid). Many cyclic hydrocarbons were detected: indole, phenol, p-cresol and piperidin-2-one are some examples. The aldehydes are also present, overall butanal, hexanal, heptanal and nonanal. We however found no trace of cadaverine or putrescine. Our results may have potential implication in a better understanding of the olfactive signature of a human or animal cadaveric corpse. Especially in the field of forensic entomology, these chemical compounds may have an attractive role on the necrophagous insect behaviour. Further studies based on the relationships that may exist between cadaveric VOCs and necrophagous insects are currently conducted at the Department of functional and evolutionary Entomology (GxABT, Ulg). [less ▲]

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See detailLipase synthesis of fatty acid sugar esters in pure ionic liquids
Galonde, Nadine ULg

Poster (2010, October 14)

Sugar fatty acid esters are broadly consumed in many commercial applications and their synthesis gained a considerable interest since they are biodegradable, tasteless, odorless, non-toxic and non ... [more ▼]

Sugar fatty acid esters are broadly consumed in many commercial applications and their synthesis gained a considerable interest since they are biodegradable, tasteless, odorless, non-toxic and non-irritant. Ionic liquids are organic salts entirely comprised of ions with a melting point below 100°C. This new category of solvent may allow the enzymatic synthesis of sugar fatty acid ester to go toward a “greener” process. Within the purpose of using “green” systems for synthesis of glycosylated compounds, studies on the use of ionic liquids to obtain fatty acid sugar esters with carbohydrates coming from lignocellulosic material as substrates was carried out. The enzymatic synthesis of mannose myristate ionic liquids as enzymatic medium and the yield obtained will be presented in our poster. [less ▲]

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See detailA method for the production of prebiotic preparations containing isomaltooligosaccharides and gluconic acid.
Goffin, Dorothée ULg; Blecker, Christophe ULg; Paquot, Michel ULg

Poster (2010, October 14)

Isomaltooligosaccharides (IMOs) are non-digestible oligosaccharides, considered as prebiotics and therefore aim to selectively feed probiotics indigenous to the human colon. IMOs consists of glucose ... [more ▼]

Isomaltooligosaccharides (IMOs) are non-digestible oligosaccharides, considered as prebiotics and therefore aim to selectively feed probiotics indigenous to the human colon. IMOs consists of glucose monomers linked by at least one α-1-6, or in a lower proportion α -1-3 (nigerose family) or α -1-2 (kojibiose family) glucosidic linkages. In our case they are produced from either corn, tapioca, or rice hydrolyzed starch. The enzymatic reaction is achieved using an Aspergillus niger transglucosidase (EC 2.4.1.24). It results in a very complex mixture with molecules characterized at the same time by their DP value (from 2 to ~15), linkages types (α-1-2, 3 or 6) and the proportion and position of each type of linkage (only α -1-6 or combined types). However, the reaction only permits to reach yields between 50-75 % in IMOs. Impurities are composed of residual maltooligosaccharides (glucose with exclusively α -1-4 linkages) from the starting vegetal material and glucose released during the transglucosylation step. These digestible saccharides are deleterious for the prebiotic preparation. Therefore, these compounds must be eliminated from the medium or converted in prebiotic species. Residual maltooligosaccharides are thus specifically hydrolyzed by a thermostable α-glucosidase (EC. 3.2.1.20) in order to produce glucose as the only unwanted specie. This glucose can then be converted to gluconic acid and/or its salts using a glucose-oxidase (EC. 1.1.3.4) in combination with a catalase. Gluconic acid (C6H12O7) is a saccharide derivative which has been recognized as a prebiotic compound. It is also known for its purgative action and proved to be effective for lipid peroxidation prevention. A first option can then be chosen, leaving gluconic acid in the product in order to obtain an original prebiotic product enjoying new prebiotic potential properties due to the combination of both types of prebiotic compounds (IMO and gluconic acid). The second option is to eliminate the gluconic acid from the prebiotic mixture. This separation doesn’t present the same difficulties than for glucose as gluconic acid is charged and can therefore be separated on anion-exchange resins (Dowex AcO-). This overall process, fulfilling the principles of green chemistry and being applicable to produce organic prebiotic, is an elegant solution, from an economical, an environmental, a nutri-functional and a techno-functional point of view. Indeed, it can lead to original prebiotic preparations, with yields close to 100%, by avoiding product loss, as the digestible saccharides portion is converted to gluconic acid. Furthermore, the presence of gluconic acid can provide many functional properties to the prebiotic preparations for their incorporation in food products. [less ▲]

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See detailA Boolean network model of the growth plate
Kerkhofs, Johan ULg; Roberts, Scott J; Luyten, Frank P et al

Poster (2010, October 10)

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See detailEmotional facial expressions decoding in siblings of children with autism
Dethier, Marie ULg; Sojic, Barbara ULg; Blairy, Sylvie ULg

Poster (2010, October 08)

The ability to identify other people’s emotions, including their emotional facial expression (EFE), is fundamental to many social processes. Individuals with autism spectrum disorders (ASD) show deficits ... [more ▼]

The ability to identify other people’s emotions, including their emotional facial expression (EFE), is fundamental to many social processes. Individuals with autism spectrum disorders (ASD) show deficits in several empathy-related processes, including EFE decoding (e.g. Ashwin, Chapman, Colle, & Baron-Cohen, 2007). The object of this study was to investigate the capacity to decode accurately EFE in siblings of children with ASD. Indeed, autism is considered to be substantially influenced by genetic factors and relatives of ASD individuals present different type of deficits including the domains of language, theory of mind, and executive functioning (e.g., Fombonne, Bolton, Prior, Jordan, & Rutter, 1997). Fifteen 6-to-15 years old siblings of children with ASD were compared to matched siblings of typically developing children on a decoding task of adults EFE. The children had to match a story depicting an adult in an emotional situation to a picture of an adult EFE. The emotions investigated were joy, anger, sadness, fear, surprise, disgust, and contempt. The differences of EFE accuracy between siblings of ASD and siblings of typically developing children are discussed in reference to the characteristics of the relationship with their ASD brother or sister. [less ▲]

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See detailOptimisation of new biodegradable microcarriers tailored for tissue engineering
Tsoy, A; Sevrin, Chantal ULg; Kottgen, C et al

Poster (2010, October 07)

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See detailDiscussing the validation of high-dimensional probability distribution learning with mixtures of graphical models for inference
Schnitzler, François ULg

Poster (2010, October 06)

Exact inference on probabilistic graphical models quickly becomes intractable when the dimension of the problem increases. A weighted average (or mixture) of different simple graphical models can be used ... [more ▼]

Exact inference on probabilistic graphical models quickly becomes intractable when the dimension of the problem increases. A weighted average (or mixture) of different simple graphical models can be used instead of a more complicated model to learn a distribution, allowing probabilistic inference to be much more efficient. I hope to discuss issues related to the validation of algorithms for learning such mixtures of models and to high-dimensional learning of probabilistic graphical models in general, and to gather valuable feedback and comments on my approach. The main problems are the difficulties to assess the accuracy of the algorithms and to choose a representative set of target distributions. The accuracy of algorithms for learning probabilistic graphical models is often evaluated by comparing the structure of the resulting model to the target (e.g. Number of similar/dissimilar edges, score BDe etc). This approach however falls short when studying methods using a mixture of simple models : individually, these lack the representation power to model the true distribution, and only their combination allows them to compete with more sophisticated models. The Kullback-Leibler divergence is a measure of the difference between two probability densities, and can be used to compare any model learned from a dataset to the data generating distribution. For computational reasons, I however had to resort to a Monte Carlo estimation of this quantity for large problems (starting at around 200 variables). Since probabilistic inference is the ultimate motivation for building these models, and not probability modelling, a more meaningful measure of accuracy could be obtained by comparing mixtures against a combination of state of the art model learning and approximate inference algorithms. However, the exact inference result cannot be easily assessed for interesting target distributions, since the use of mixtures is precisely considered because exact inference is not possible on said targets, and approximate inference would introduce a bias. Selecting a target distribution used to generate the data sets on which the algorithms are evaluated also proved a challenge. The easiest solution was to generate them at random (although different approaches can be designed). These models are however likely to be rather different from real problems, and thus constitute a poor choice to assess the practical interest of mixture of models. Methods (e.g. linking multiple copies of a given network) have been developed to increase the size of models known by the community (e.g. the alarm network), and the obtained graphical models have been made available. These could however still be far from the kind of interactions present in a real setting. A better way to proceed could be to generate samples based on the equations describing a physical problem, to learn a probabilistic model as best as possible from this high-dimensional dataset, and to use it as target distribution. [less ▲]

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See detailCongo River 2010
Darchambeau, François ULg; Borges, Alberto ULg; Wabakanghanzi, José Nlandu et al

Poster (2010, October 04)

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See detailNew strategy to in vitro evaluation of antimalarial drugs demonstre advantage of Artemisia annua crude extract on antimalarial effect by its tools to cross intestinal barrier
Melilo de Magalhaes, Pedro; Schneider, Y. J.; Dupont, Isabelle et al

Poster (2010, October 03)

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See detailTop-down role of fish predators in structuring amphipod community associated to Posidonia oceanica seagrass meadows
Sturaro, Nicolas ULg; Lepoint, Gilles ULg; Panzalis, Pier et al

Poster (2010, October)

Despite the major ecological importance of Posidonia oceanica seagrass meadows in the Mediterranean Sea, little attention has been given to community structuring forces by predators in this ecosystem. To ... [more ▼]

Despite the major ecological importance of Posidonia oceanica seagrass meadows in the Mediterranean Sea, little attention has been given to community structuring forces by predators in this ecosystem. To better understand the mechanisms by which fishes affect amphipod community structure associated to P. oceanica beds, experimental manipulations of predation intensity (enclosure and exclusion cages) were set up in the Tavolara-Punta Coda Cavallo Marine Protected Area (Sardinia, NW Mediterranean). In totally protected area, where high abundance of predatory fishes is recorded, we have performed exclusion experiment. Total amphipod abundance increased at the end of the experiment, but diversity and specific composition were unaffected. At the species taxonomic level, significant increase in abundance between treatments appeared only for Caprella acanthifera. In partially protected area, where fish abundance is lower and amphipod abundance higher, individuals of the carnivorous fish Coris julis (Labridae) were enclosed in cages to provide an estimate of the potential for this species to impact on amphipod community. There was a small but measurable effect on amphipod abundance between enclosures and unmanipulated controls. A few dominant amphipod species responded to fish predation by significant decrease in abundance. These results suggest that fish predation may determine the relative abundances in the community of some amphipod species and to some degree, through an untested link with habitat complexity, determine the spatial distribution of amphipod abundance within P. oceanica beds. Moreover, patterns observed at the species level, suggest parallel complex interactions probably mainly related to ecological behaviour of amphipod species. [less ▲]

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See detailPEPTIDE-LOADED LIPOSOMES AGAINST BREAST CANCER: EFFECTIVE PENETRATION IN CELLS OF LONG CIRCULATING pH-SENSITIVE VESICLES
Ducat, Emilie ULg; Deprez, Julie ULg; Peulen, Olivier ULg et al

Poster (2010, October)

Purpose: Print3G, a peptidic antagonist of oncoprotein involved in breast cancer, could reduce the angiogenic development of breast tumors. The necessity of intravenous administration of Print3G led to ... [more ▼]

Purpose: Print3G, a peptidic antagonist of oncoprotein involved in breast cancer, could reduce the angiogenic development of breast tumors. The necessity of intravenous administration of Print3G led to the development of liposomes as drug carriers, combining the protective properties of PEG with the transfection properties of pH-sensitive lipids. The purpose of this work is to compare pegylated pH-sensitive liposomes with a classical formulation of long-circulating liposomes in terms of cellular uptake. Methods: Classical liposomes (SPC:CHOL:mPEG-750-DSPE (47:47:6 mol/mol)) and pH-sensitive liposomes (DOPE:CHEMS:CHOL: mPEG750-DSPE (43:21:30:6 mol/mol)) were compared in terms of size, charge, stability, pH-sensitivity and toxicity by inhibition of cell proliferation. Finally, confocal microscopy was used to study the cellular uptake of liposomes by three cell lines (Hs578t, WI-26 and MDA-MB-231), using 25-nitrobenzoxydiazol-cholesterol as a fluorescent marker of the vesicular membrane and rhodamine in the inner cavity of liposomes. Results: Sizes of 162.8 ± 4.6 nm and zeta potential of -9.3 ± 1.2 mV were obtained for standard liposomes (n=3) while the obtained values for pH-sensitive liposomes (n=3) were respectively of 184.8 ± 3.2 nm and -19.5 ± 2.6 mV. The two formulations were comparable in terms of shape and stability. Concerning the pH-sensitivity study, a significantly higher leakage of the encapsulated material was observed at pH 5 for pH-sensitive liposomes. Confocal pictures obtained with these vesicles on the three cell lines allowed us to visualize the colocalized red and green color with a higher concentration near the nucleus. Conclusion: Long circulating pH-sensitive liposomes are promising drug delivery systems in terms of cellular uptake. Experiments will be performed with biotinylated Print3G to assess its cellular distribution. Moreover, the accumulation of this formulation in breast tumor will be evaluated by in vivo studies. [less ▲]

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See detailAnálisis ecomorfológico de la aleta pectoral en damiselas (Perciformes, Pomacentridae) del Pacífico Oriental
Aguilar-Medrano, Rosalia; Frederich, Bruno ULg; De Luna, Efrain et al

Poster (2010, October)

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See detailPersistance des troubles psychologiques et comportementaux de la démence
Squelard, Gilles ULg; Adam, Stéphane ULg; Missotten, Pierre ULg et al

Poster (2010, October)

est considérable. Actuellement, la sélection d’un traitement dépend de la nature du trouble et de son intensité. La connaissance de leur persistance s’avère importante pour la sélection et l’organisation ... [more ▼]

est considérable. Actuellement, la sélection d’un traitement dépend de la nature du trouble et de son intensité. La connaissance de leur persistance s’avère importante pour la sélection et l’organisation du traitement. Objectifs: Evaluer la persistance des troubles psychologiques et comportementaux dans une population de sujets déments suivis longitudinalement. Méthodes: Nous avons sélectionné 104 sujets déments issus de l’étude Qualidem (Paquay et al., 2004). Tous les sujets sont institutionnalisés et présentent des perturbations cognitives (score MMSE<20). Les troubles psychologiques et comportementaux ont été évalués à 12 mois d’intervalle avec le Neuropsychiatric Inventory (Cummings et al., 1997). Résultats: Les perturbations les plus persistantes sont les idées délirantes (62%), et l’agitation (67%). Le risque de rechute est moins important pour la dépression (54%), les hallucinations (44%), l’exaltation de l’humeur (43%), l’apathie (48%), l’irritabilité (52%), et le comportement moteur aberrant (52%). L’anxiété (38%), la désinhibition (39%), les troubles du sommeil (39%) et de l’appétit (38%) sont les moins persistants. Conclusion: La nature persistante de l’agitation et des idées délirantes suggère que le traitement de ces perturbations doit être prolongé. La nature ponctuelle de l’anxiété, la désinhibition et des troubles de l’appétit et du sommeil suggère qu’un traitement à court terme est plus approprié pour ces perturbations. Ces résultats sont à interpréter par rapport à la définition des troubles induite par le NPI. [less ▲]

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See detailEffect of kynurenic acid on sensitivity to cortical spreading depression in rats
Chauvel, Virginie ULg; Vamos, Eniko; Pardutz, Arpat et al

Poster (2010, October)

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See detailProjet thérapeutique n°99 "Personnes âgées" et travail en réseau
Squelard, Gilles ULg; Vilain, Anne; Jacob, Bernard

Poster (2010, October)

Introduction : En Belgique, le secteur de la santé mentale est en pleine mutation. Afin d’améliorer l’efficacité des soins, les pouvoirs publics ont décidé de réorganiser l’offre de soins par la ... [more ▼]

Introduction : En Belgique, le secteur de la santé mentale est en pleine mutation. Afin d’améliorer l’efficacité des soins, les pouvoirs publics ont décidé de réorganiser l’offre de soins par la réalisation de « circuits et réseaux de soins ». Cette réforme se construit par phases successives, et c’est dans ce cadre qu’ont été activés les projets thérapeutiques. Ces recherches-actions se concrétisent par le développement de la fonction de concertation autour de patients et de leur famille. Leur finalité est d’améliorer la continuité des soins et de proposer des soins sur mesure dont le patient est l’élément central. Le projet thérapeutique n°99 « personnes âgées » vise le maintien dans leur milieu de vie de personnes de plus de 65 ans vivant en Province de Liège et présentant une problématique psychiatrique chronique et complexe. Objectif Communication de nos principales recommandations concernant la mise en place de la fonction de concertation et à la formalisation du travail en réseau dans le tissu gérontologique liégeois. Méthodologie : Le projet thérapeutique n°99 vise les personnes âgées de 65 et plus, habitant en Province de Liège et présentant une pathologie psychiatrique spécifique : démence, abus d’alcool, abus d’opiacés, abus d’hypnotiques, anxiolytiques ou sédatifs, schizophrénie, ou trouble schizo-affectif. Le projet repose sur une démarche empirique. Il consiste en l’organisation de réunions de concertation pluridisciplinaires autour de patients et de leur famille dont la finalité est la mise en place d’un suivi individualisé. Nous nous appuyons sur ces situations cliniques chroniques et complexes pour mettre en place des procédures de travail en réseau. Résultats : Nous avons suivi environ 80 patients dont l’âge moyen est de 80.1 ans. La plupart des patients suivis (80%) présentent une démence. La coordination du projet opère un travail sur deux axes distincts: l’axe institutionnel et professionnel, et le niveau clinique. L’action ciblant le réseau vise le développement d’une culture de travail en réseau. Celle-ci se construit progressivement à travers une sensibilisation des professionnels au travail de concertation pluridisciplinaire. En ce qui concerne le travail clinique, nous nous sommes focalisés sur la gestion de la concertation pluridisciplinaire. Ce travail se décompose en trois phases : la phase préparatoire, la réunion de concertation, et le suivi. Des procédures de travail ont été mises en place pour en faciliter l’organisation (plan de service, agent de suivi). Conclusion : Le développement de la fonction de concertation a suscité un remaniement dans le mode de fonctionnement des professionnels de terrain, souvent peu familiarisés au travail en réseau et à la collaboration « extérieure ». L’instauration de la culture de travail en réseau via un accompagnement, une sensibilisation, et la mise à disposition de procédures favorisant la collaboration interdisciplinaire s’avère nécessaire. Outre les bénéfices cliniques relevés, il apparaît après trois ans de fonctionnement que la concertation autour de personnes souffrant de problématiques chroniques complexes constitue un moyen efficace de maintien du lien interprofessionnel, et facilite la connaissance et la collaboration des partenaires. [less ▲]

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See detailMir-146a : A new angiostatic miRNA with tumor-suppressive properties
Halkein, Julie ULg; Castermans, Karolien; Malvaux, Ludovic et al

Poster (2010, October)

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See detailIntroduction of the asymptotic study of the estimation of the error distribution in right censored and selection biased regression models
Laurent, Géraldine ULg; Heuchenne, Cédric ULg

Poster (2010, October)

Consider the regression model Y = m(X) + σ(X) Ɛ where m(X) = E[Y|X] and σ²(X)=Var[Y|X] are unknown smooth functions and the error Ɛ , with unknown distribution, is independent of the covariate X. The pair ... [more ▼]

Consider the regression model Y = m(X) + σ(X) Ɛ where m(X) = E[Y|X] and σ²(X)=Var[Y|X] are unknown smooth functions and the error Ɛ , with unknown distribution, is independent of the covariate X. The pair (X;Y) is subject to generalized bias selection and the response to right censoring. We construct a new estimator for the cumulative distribution function of the error Ɛ , where the estimators of m(.) and σ²(.) are obtained by extending the conditional estimation methods introduced in de Uña-Alvarez and Iglesias-Perez (2008). The asymptotic properties of the functions m(.) and σ(.) are obtained. A bootstrap technique is proposed to select the smoothing parameter involved in the procedure. This method is studied via extended simulations and applied to real unemployment data. [less ▲]

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See detailShading and alterations of the sediment: in situ experiments to mimic impacts of fish farms on a Mediterranean coastal ecosystem
Pete, Dorothée ULg; Velimirov, Branko; Lepoint, Gilles ULg et al

Poster (2010, October)

In the Mediterranean coastal zone, the seagrass Posidonia oceanica forms underwater meadows which sustain a high biodiversity and has many important roles (production of oxygen, protection of coasts ... [more ▼]

In the Mediterranean coastal zone, the seagrass Posidonia oceanica forms underwater meadows which sustain a high biodiversity and has many important roles (production of oxygen, protection of coasts, ...). Unfortunately, they are more and more threaten, notably by the increasing development of aquaculture. Indeed, fish farms increase the biomass of phytoplankton organisms in the water column (leading to a shading effect) and modify the sediment, which entail the disappearance of the seagrass. To understand the impact of those troubles on P. oceanica and the ecosystem, in situ experiments were led during three months, in STARESO (STAtion de Recherches Sous- marines et Océanographiques; Calvi, Corsica), at a depth of 10 meters. The shading was mimicked by shading frames, which stopped around 50 % of the incident light. To modify the sedimentary compartment, sediment was taken from under the aquaculture of Calvi and added once a week on marked zones in the meadow. Those sites were compared with a control site, situated near them. Measured parameters are: the concentration of nutrients in pore water, grain size, redox potential discontinuity, biomasses of bacteria, organic matter, meiofauna and microphytobenthos within the sediment, the length, width, biomass and chlorophyll a content of P. oceanica leaves and the biomass of epiphytes. During those experiments, P. oceanica was not very affected although some parameters of the sedimentary compartment were modified. These results show that the sedimentary compartment reacts more rapidly to threats then the seagrass itself. So, it could be an interesting tool in quality assessments. [less ▲]

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See detailTree species effects on soil microbial activities in a young stand
Guillaume, Patricia ULg; Bazgir, Masoud; Carnol, Monique ULg et al

Poster (2010, October)

Tree species effects on soil characteristics and biogeochemistry are mediated by several factors including microclimatic conditions, ground vegetation cover, quality and quantity of litter and roots ... [more ▼]

Tree species effects on soil characteristics and biogeochemistry are mediated by several factors including microclimatic conditions, ground vegetation cover, quality and quantity of litter and roots exudates, interception of atmospheric particules and aerosols, as well as secondary metabolites from litter. Moreover, the effects depend on the activities and characteristics of the microbial populations. Due to complex interactions, tree species effects on biogeochemical cycles may vary according to soil type, site characterisitcs and history, and climate. However, these questions about tree species effects on biogeochemical cycles are of central interest to forested ecosystems functions, such as soil quality (restoration) and soil water protection. This work is part of a long-term study on concentrations and fluxes in main compartments of 2 forested watersheds (Waroneu and Robinette, east Belgium) in relation with forest management. After 2 spruce generations, the Robinette catchment was partially clear-cut in 1996. Since 1998, this watershed is experiencing an ‘extensive’ afforestartion with a mixture of main and secondary tree species, adapted to specific site conditions. This site, provides the opportunity to study tree species effects on the same soil, with the same history. Morever, tree species have different ecological characteristics: N2 fixing species (Alnus glutinosa), secondary broadleaved species (Betula pendula, Sorbus aucuparia, Salix aurita), main broadleaved sepcies (Quercus robur and Fagus sylvatica) and spruce (Picea abies). Here, we analysed the effects of tree species on soil pH and soil microbial activities in the organic layer in relation to carbon and nitrogen cycles: microbial biomass, basal respiration, labile carbon, nitrogen net mineralisation and potential nitrification. Twelve years after plantation, our results showed differences below the different tree species: (1) a higher microbial biomass and a higher substrate use efficiency and organic matter accessbility for microbial populations below spruce as compared with other tree species; (2) higher pH and microbial biomass below secondary than below main broadleaved species; (3) an enhanced nitrification below alder; (4) a higher leaching of nitrate below broadleaved species than below spruce. These results show a short term impact of forest tree species on microbial activities in upper soil layers. Results are discussed in relation to ecological characteristics of tree species. [less ▲]

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Peer Reviewed
See detailRevisited rules of papilla level adjacent to single-tooth dental implants according recent implant designs. A retrospective study.
LECLOUX, Geoffrey ULg; Beaujan, Laurie; ROMPEN, Eric ULg et al

Poster (2010, October)

Background: According to Choquet and Tarnow principles (2001), a papilla is always present if the distance from the base of the contact point between two crowns to the crest of the bone is 5 mm or less ... [more ▼]

Background: According to Choquet and Tarnow principles (2001), a papilla is always present if the distance from the base of the contact point between two crowns to the crest of the bone is 5 mm or less. The arrival of new designs in implantology suggested more tissue preservation and so a possible evolution for the aesthetic treatments. Aim: This study was designed to determine whether the distance from the base of the contact point to the crest of the bone would correlate with the presence or absence of the interproximal papillae adjacent to single-tooth implants using the recent implant designs. Methods: A clinical, photographical and radiographical retrospective evaluation of the papilla level around single dental implants and their adjacent teeth was performed in the anterior maxilla in 34 patients restored with 39 implants. These implants were loaded at least 6 months and present a modified profile (Implants : NobelConcept and NobelActive, Nobel Biocare ; Bone Level, Straumann. Abutments : Platform-switching and curvy). Sixty-three papillae were available for evaluation. The Jemt index, the vertical distance between the base of the contact point and the bone crest, the distance from the papilla level to the contact point were measured. The measurements were rounded off to the nearest 0,001 millimeter and used with calibration computer programs (ImageJ) to be analyzed. The statistical analyses were realized with SAS program (SAS Institute, Cary, NC, USA). Results: When the measurements from the contact point to the crest of bone was 5 mm or less, the papilla was present 100% of the time. When the distance was 6 mm, the papilla was present 96% of the time. And when the distance was 7 and 8 mm, the papilla was present 57,14% and 50% of the time. Conclusions and clinical implications: These results show the influence of the bone crest on the presence or absence of papillae between implants and adjacent teeth. The data also show a positive influence for recent designs of implant and abutment systems. This designs shift the actual critical bone distance under the contact point from 5mm to 6mm and could improve the aesthetic outcome. [less ▲]

Detailed reference viewed: 48 (0 ULg)