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See detailAmmonia oxidizing bacteria community structure and richness under coniferous/deciduous tree species at three temperate forest sites
Malchair, Sandrine ULg

Poster (2014, November)

Ammonia Oxidizing Bacteria community structure and richness under coniferous/deciduous tree species at three temperate forest sites Malchair S. and Carnol M. Laboratory of Plant and Microbial Ecology ... [more ▼]

Ammonia Oxidizing Bacteria community structure and richness under coniferous/deciduous tree species at three temperate forest sites Malchair S. and Carnol M. Laboratory of Plant and Microbial Ecology Department Biology, Ecology and Evolution University of Liege, Belgium Introduction: Despite the crucial roles of soil microorganisms in ecosystem processes, numerous uncertainties subsist on the relationship between soil microbial diversity and function. Furthermore, the link between aboveground and belowground diversity remains also unclear. In European forests, at the beginning of the 19th century, plantations of Norway spruce and Scots pine for timber production were substantially increased. However, concerns were expressed with regard to the ecological risks posed by coniferous monocultures. The conversion of these monocultures into broadleaved or mixed stands has been suggested as a solution. Nevertheless, belowground effects of such a change in the dominant tree species is largely unknown, although bacteria regulate many soil processes and some groups, like ammonia oxidizing bacteria (AOB) are highly sensitive to environmental stresses. Objectives: The aims of this study were to investigate (i) AOB community structure and richness under several tree species, (ii) microbial/environmental factors influencing AOB diversity, (iii) the relationship between AOB diversity and the nitrification process. Materials and methods: Forest floor (Of, Oh) was sampled under Norway spruce, Douglas fir, European beech and sessile oak at three temperate forest sites. AOB diversity (community structure and richness) was assessed by PCR-DGGE and sequencing. Samples were analysed for microbial (net N mineralization, potential nitrification, basal respiration, microbial biomass, microbial or metabolic quotient) and environmental parameters (pH, total nitrogen, extractable ammonium, organic matter content and exchangeable cations). Results: AOB sequences retrieved in this study were related to different uncultured strains from soils, related to both Nitrosospira-like and Nitrosomonas-like sequences. AOB community structure and tree species effects on AOB diversity were site-specific. AOB community structure was influenced by environmental/microbial parameters, i.e. net N mineralization or organic matter content, regulating ammonium availability. AOB richness was not related to nitrification but a very weak correlation between potential nitrification and AOB community structure was observed. Conclusions: At larger spatial scales, site specific characteristics may be more important that tree species in determining AOB richness and community structure. However, within sites, tree species influence AOB diversity. The absence of a clear relationship between AOB diversity and nitrification points to a possibly role of AOB abundance, phenotypic plasticity or the implication of ammonia oxidizing archaea in this process. [less ▲]

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See detailDistribution and robustness of a distance-based multivariate coefficient of variation
Aerts, Stéphanie ULg

Poster (2014, November)

When one wants to compare the homogeneity of a characteristic in several popula- tions that have di erent means, the advocated statistic is the univariate coe cient of variation. However, in the ... [more ▼]

When one wants to compare the homogeneity of a characteristic in several popula- tions that have di erent means, the advocated statistic is the univariate coe cient of variation. However, in the multivariate setting, comparing marginal coe cients may be inconclusive. Therefore, several extensions that summarize multivariate relative dispersion in one single in- dex have been proposed in the literature (see Albert & Zhang, 2010, for a review). In this poster, focus is on a particular extension, due to Voinov & Nikulin (1996), based on the Mahalanobis distance between the mean and the origin of the design space. Some arguments are outlined for justifying this choice. Then, properties of its sample version under elliptical symmetry are discussed. Under normality, this estimator is shown to be biased at nite samples. In order to overcome this drawback, two bias corrections are proposed. Moreover, the empirical estimator also su ers from a lack of robustness, which is illustrated by means of in uence functions. A robust counterpart based on the Minimum Covariance Determinant estimator is advocated. [less ▲]

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See detailRobust detection of local outliers in multivariate spatial data
Ernst, Marie ULg

Poster (2014, November)

Multivariate spatial data are geographical locations on which non spatial variables are measured. Such data may contain two types of outliers: global and/or local. Focus is here on local outlier whose ... [more ▼]

Multivariate spatial data are geographical locations on which non spatial variables are measured. Such data may contain two types of outliers: global and/or local. Focus is here on local outlier whose attribute values lie far from the values taken by its neighbors. This poster has three main objectives. The first is to review some local detection techniques that seem to perform well in practice. Secondly, an adaptation to one of these is suggested to further develop its local characteristic. Then simulations based on Matérn model are reported and discussed in order to compare in an objective way the different detection techniques. [less ▲]

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See detailImpact of the dialysis membrane on the Vitamin D metabolims markers
CAVALIER, Etienne ULg; DUBOIS, Bernard ULg; Urena, Pablo et al

Poster (2014, November)

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See detailHighly sophisticated compound droplets on fiber arrays
Weyer, Floriane ULg; Lismont, Marjorie ULg; Dreesen, Laurent ULg et al

Poster (2014, November)

The poster shows a drop of oil containing four soapy water droplets of four different colors : red, orange, green and blue. This sophisticated object is created thanks to a fiber array. Fiber networks ... [more ▼]

The poster shows a drop of oil containing four soapy water droplets of four different colors : red, orange, green and blue. This sophisticated object is created thanks to a fiber array. Fiber networks allow processes such as droplet motion, fragmentation, trapping, releasing, mixing and encapsulation. Therefore, by using a vertical fiber decorated with successive nodes, compound droplets can be created. A soapy water droplet, with a specific color, is placed at each intersection. Then, a silicon oil droplet glides along the vertical fiber, encapsulates and collects the water droplets at each node leading to the formation of a compound droplet with four different components. [less ▲]

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See detailImpact de la phéromone d’alarme sur l’efficacité de la transmission de virus
Bosquée, Emilie ULg; Lin, Fang Jing; Liu, Ying Jie et al

Poster (2014, November)

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See detailEtude de la forme d'arcade dentaire après nivellement en technique Damon.
LEWY, Stéphanie; LIMME, Michel ULg; BRUWIER, Annick ULg

Poster (2014, November)

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See detailTh17 cells in melanoma microenvironment
Weatherspoon, Alodie ULg; Multon, Sylvie ULg; Defaweux, Valérie ULg et al

Poster (2014, November)

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See detailCaractérisation de bois utilisés dans la construction de quatre xylophones africains à résonateurs
Warneke, Nikolaus; Houssay, Anne; Morin, Julie ULg et al

Poster (2014, November)

Nous avons besoin de collaborations avec des anatomistes pour travailler avec nous sur des méthodes d’identification des bois si possible sans ou avec le minimum de prélèvement. Notre microscope in ... [more ▼]

Nous avons besoin de collaborations avec des anatomistes pour travailler avec nous sur des méthodes d’identification des bois si possible sans ou avec le minimum de prélèvement. Notre microscope in situ facilite l’étude des collections. En cherchant à caractériser les essences de bois utilisées pour la fabrication d’instruments de musique traditionnels en Afrique, le choix du bois peut meAre en évidence la disponibilité de telle ou telle essence à un moment précis, et son apprécia1on du point de vue des musiciens. La façon de tailler les lames peut montrer des échanges culturels et techniques ou au contraire des pratiques spécifiques. L’étude des accords peut donner des échelles musicales communes ou au contraire distinctes. La richesse des timbres produits suivant ces choix peut être un élément culturel, technique et esthétique. Patrimoine naturel et musical sont ainsi mis en relation. [less ▲]

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See detailComputergestützte Förderung der mündlichen Leistung im Fremdsprachenunterricht - Die @lter Fremdsprachkurse an der Universität Lüttich (ULg), Belgien
Thonard, Audrey ULg; Jérôme, Françoise ULg; Badir, Yasmine ULg et al

Poster (2014, October 30)

The poster présents the implementation of voice tools in the service of foreign language learning at the University of Liège. Oral skills (comprehension and production) are trained online in autonomy and ... [more ▼]

The poster présents the implementation of voice tools in the service of foreign language learning at the University of Liège. Oral skills (comprehension and production) are trained online in autonomy and with instructors' interventions. The setting also provides facilities for oral feedbacks. [less ▲]

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See detailRecyclage des briques cassées pour améliorer les propriétés céramiques des argiles plastiques (Meknès, Maroc)
El Ouahabi, Meriam ULg; Daoudi, Lahcen; El Boudour El Idrissi, Hicham ULg et al

Poster (2014, October 27)

Dans le Bassin de Saïs (nord ouest du Maroc), les argiles du Miocène de la région de Meknès sont utilisées dans l’industrie céramique locale pour la fabrication des briques. Ces argiles riches en smectite ... [more ▼]

Dans le Bassin de Saïs (nord ouest du Maroc), les argiles du Miocène de la région de Meknès sont utilisées dans l’industrie céramique locale pour la fabrication des briques. Ces argiles riches en smectite et en carbonates, ont une granulométrie très fine, marquée par la quasi absence de la fraction sableuse. Ces propriétés les rendent très plastiques, ce qui engendre des taux de retrait importants au séchage et à la cuisson et des problèmes de qualité du produit fini qui s’en suivent (fissurations, déformations et casses pendant les processus de séchage et de cuisson). Dans le but de palier à ce problème et d’améliorer la qualité du produit fini, nous proposons au cours de cette étude de recycler les déchets de briques cassées. Afin d'atteindre ces objectifs, 4 formulations ont été réalisées à base d’argiles plastiques, riches en smectite et des casses de briques broyées. Des quantités de 5, 10, 15 et 20% de briques broyées ont été ajoutées à la pâte destinée à la confection des briques. Des analyses minéralogiques par diffraction des rayons X (DRX), chimiques par spectrométrie de fluorescence (XRF), granulométrique par granulométrie laser, ainsi que les limites d’Atterberg ont été effectuées. Les résultats minéralogiques montrent une diminution de la teneur en carbonates (calcite) et en argile totale (principalement smectite), lors des ajouts successifs de briques broyées. La fraction sableuse augmente progressivement, jusqu’à atteindre 30% pour une formulation avec 20% de casses de briques. Cette granulométrie plus grossière diminue la plasticité de la pâte et permet d’éviter les déformations et les fissures pendant le processus du séchage. De plus, l’ajout des casses de briques dilue les carbonates, ce qui permet d’améliorer la qualité du produit cuit. Ces résultats indiquent que le recyclage des déchets de briques, présente un intérêt à la fois économique et écologique. Des essais de comportement au séchage et à la cuisson ainsi que des essais mécaniques complèteront cette étude. [less ▲]

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See detailReformage catalytique du toluène
Claude, Vincent ULg; Lambert, Stéphanie ULg; Courson, Claire

Poster (2014, October 23)

This poster summarizes results obtained for the catalytic reforming of tar in the oultlet gas of a biomass gasifier. All samples were synthesized with aluminum nitrate and an organosilane (EDAS) in order ... [more ▼]

This poster summarizes results obtained for the catalytic reforming of tar in the oultlet gas of a biomass gasifier. All samples were synthesized with aluminum nitrate and an organosilane (EDAS) in order to enhance the metallic dispersion and surface area. Three different compositions have been studied (Al2O3-SiO2; Al2O3-SiO2+2%wt Ni; Al2O3-SiO2+10%wt Fe). The catalytic tests highlight the fact that the sample containing 2%Ni wt is the more appropriate in our conditions. [less ▲]

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Peer Reviewed
See detailSurfactin interaction with model plant plasma membrane
Luzuriaga Loaiza, Walter ULg; Nasir, Mehmet Nail ULg; Lins, Laurence ULg et al

Poster (2014, October 20)

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See detailAnalysis of the interactions of natural elicitor rhamnolipids with plant plasma membranes by in silico methods
Polo Lozano, Damien ULg; Nasir, Mehmet Nail ULg; Deleu, Magali ULg et al

Poster (2014, October 20)

Rhamnolipids are surface active molecules produced mainly by various strains of the bacterium Pseudomonas aeruginosa. These secondary metabolites are composed of one to three fatty acids with various ... [more ▼]

Rhamnolipids are surface active molecules produced mainly by various strains of the bacterium Pseudomonas aeruginosa. These secondary metabolites are composed of one to three fatty acids with various chain lengths linked through a glycosidic bond to one or two rhamnose moieties. The fatty acids are linked together through an ester bond. These molecules have shown several biological activities including plant defense stimulation. It has be suggested that this elicitor activity could be related to an interaction of rhamnolipids with the lipid bilayer of the plant plasma membrane (PPM) and lead to its destabilization, which can activate the plant defense signaling pathways. In this context, interactions of two rhamnolipids (Rha-C10-C10 and Rha-Rha-C10-C10) with membrane models and lipidic constituents of the PPM were investigated using in silico approaches. Most probable chemical structures of the rhamnolipids were determined using the STRUCTURE TREE procedure according to the molecule potential energy. The ability of these rhamnolipid structures to insert within the PPM was assessed using IMPALA simulations. IMPALA uses a membrane model in which phospholipids molecules are implicitly modeled by an empirical function and the membrane properties are modeled by energetic restraints. The ability of each rhamnolipid structure to form an assembly with several PPM constituents (phospholipid (PLPC), sterols (Sitosterol, Stigmasterol, Campesterol) and sphingolipids (GIPC, Glucosylceramide)) was calculated using the HYPERMATRIX procedure, which calculate and minimize the energies of interaction between all molecules of the complex until the lowest energy structure is reached. [less ▲]

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See detailCharacterization of collagen fibrils after equine suspensory ligament injury: an ultrastructural and biochemical approach
Shikh Al Sook, Mohamad Khir ULg; Gabriel, Annick ULg; Salouci, Moustafa et al

Poster (2014, October 19)

Suspensory ligament (SL) injuries are an important cause of lameness in horses. The mechanical properties of connective tissue in normal and pathological ligaments are mainly related to the fibril ... [more ▼]

Suspensory ligament (SL) injuries are an important cause of lameness in horses. The mechanical properties of connective tissue in normal and pathological ligaments are mainly related to the fibril morphology, as well as the collagen content and types. The purpose of this study was to evaluate, using biochemical and ultrastructural approaches, the alterations in collagen fibrils after injury. Eight Warmblood horses with visible signs of injury in only one forelimb SL were selected and specimens were examined by transmission electron microscope (TEM). Collagen types I, III and V were purified by differential salt precipitation after collagen extraction with acetic acid containing pepsin. TEM revealed abnormal organization as well as alterations in the diameter and shape of fibrils after SL injury. The bands corresponding to types I, III and V collagen were assessed by densitometry after sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Densitometric analysis indicated that the proportions of type III and type V collagen were significantly higher (P <0.001) in damaged tissues compared to normal tissues with a mean increase of 20.9 and 17.3% respectively. Concurrently, a significant decrease (P <0.001) in type I collagen within damaged tissues was recorded with a mean decrease of 15.2%. These alterations could be the hallmark of a decrease in the tissue quality and mechanical properties of the ligament. This provides new insight for subsequent research on tissue regeneration that may lead to the development of future treatment strategies for SL injury. [less ▲]

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See detailRole of non-polyQ regions on the aggregation process by polyQ proteins into amyloid fibrils
Huynen, Céline ULg; Willet, Nicolas ULg; Buell, Alexander K et al

Poster (2014, October 18)

Nine neurodegenerative disorders, referred to as polyglutamine diseases and including Huntington’s disease, are associated with the abnormal expansion of a polyglutamine tract inside nine unrelated ... [more ▼]

Nine neurodegenerative disorders, referred to as polyglutamine diseases and including Huntington’s disease, are associated with the abnormal expansion of a polyglutamine tract inside nine unrelated proteins. This polyQ expansion is thought to be the major determinant in the development of neurotoxicity, triggering protein aggregation into amyloid fibrils. A large body of evidence however indicates that non-polyQ regions modulate the aggregation process triggered by polyQ expansions. The interplay between the polyQ tract and non-polyQ regions is complex and still not fully understood. In order to better understand it, we previously designed and characterized model polyQ proteins made of the beta-lactamase BlaP and a 23, 30, 55 or 79Q tract inserted in position 197 or 216. These chimeras recapitulate the aggregation properties of polyQ disease-associated proteins: there is a Q-threshold for the formation of amyloid fibrils, and above the threshold, the longer the polyQ, the faster the aggregation. Moreover, the structure of BlaP (native or unfolded) and the position of insertion of the polyQ tract (197 versus 216) influence their aggregation properties. In this work, (i) we discuss the role of the conformation of the host protein, BlaP, and of the location of the polyQ within BlaP on the different phases of amyloid fibril formation, the nucleation and elongation steps, using mainly quartz crystal microbalance (QCM), atomic force microscopy (AFM). Our results highlight a linear dependence of the polyQ length on the elongation rate whatever the insertion site and the conformation of BlaP. These two parameters however drastically influence the ability of a polyQ tract to trigger the nucleation and the elongation steps of amyloid fibril formation. (ii) Finally, we investigate the precise aggregation threshold and the modulating role of the N- and C-terminal polyQ flanking sequences in position 197 of BlaP by creating and characterizing new chimeras containing intermediate length polyQ tracts in position 197, or polyQ tracts inserted between two cleavage sites in position 197, respectively. We observe that the propensity to trigger the full process of amyloid fibril formation and its rate seems to be largely dependent on the polyQ length and on the polyQ flanking sequences. Altogether our results contribute to identify the important species and elements (polyQ or non-polyQ regions, monomers, oligomers or fibrils) during the aggregation process into amyloid fibrils to interfere with the latter associated with neurotoxicity. [less ▲]

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See detailCase report : Rhabdomyolysis following acute alcohol intoxication
HALENG, Jeanine ULg; CAVALIER, Etienne ULg

Poster (2014, October 18)

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See detailDetermination of COBALT in patients with metal hip prosthesis
MISTRETTA, Virginie ULg; Charlier, Corinne ULg

Poster (2014, October 18)

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See detailThe effect of the inclusion of Urtica dioica leaves meal in diets on growth performances and carcass characteristics of broiler
Moula, Nassim ULg; Philippe, François-Xavier ULg; Michaux, Charles ULg et al

Poster (2014, October 17)

The objective of this study was to evaluate the effects of the inclusion of Urtica dioica leaves meal in diets on growth performances and carcass characteristics of broiler chicken. The study was ... [more ▼]

The objective of this study was to evaluate the effects of the inclusion of Urtica dioica leaves meal in diets on growth performances and carcass characteristics of broiler chicken. The study was conducted from May to June 2014 in the area of Chemini (Algeria). In a completely randomized design, a total of 100 one-day-old broilers (industrial strain) were divided into 2 groups and 2 repetitions with 25 chickens each. Group 1 was the control group fed a standard commercial diet based on corn and soybean purchased on the local market, whereas the birds in group 2 were fed the nettle diet (control diet with addition of 2% of nettle). The animals were housed inside in experimental pens and fed ad libitum. The results showed that nettle inclusion significantly promotes growth performance of broilers at 42 days of age (1644.8 ± 45.5 vs. 1565.1 ± 45.5g; P<0.05). The broilers fed the nettle diet had higher thigh yield (26.0 ± 0.3 vs. 25.2 ± 0.3%; P<0.05) but lower abdominal fat yield (4.39 ± 0.16 vs. 3.90 ± 0.16%; P<0.05). No significant effect of the diet was observed for carcass yield (around 71.1%) and breast percentage (around 32.40%). The overall mortality was not significantly different (P>0.05) for any of the dietary regimens (around 20%). Feed conversion ratio of the two groups were very close (around 2.17). This experiment showed that dietary inclusion of Urtica dioica has positive effects on growth performance and carcass quality of broilers. [less ▲]

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See detailMélancolie et dépression : étude phénoménologique
Ramackers, Amélia; Englebert, Jérôme ULg

Poster (2014, October 17)

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See detailFacteurs psychologiques qui influencent l’addiction à Internet: un modèle intégratif
Burnay, Jonathan ULg; Billieux, Joel; Blairy, Sylvie ULg et al

Poster (2014, October 17)

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See detailPhenotyping Belgian Blue cattle for their susceptibility to psoroptic mange
Abos, Romain ULg; Coussé, Annelies; Sarre, Charlotte et al

Poster (2014, October 17)

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See detailLocal goat in Kabylie (Chemini and Bouzeguene)
Moula, Nassim ULg; Michaux, Charles ULg; Philippe, François-Xavier ULg et al

Poster (2014, October 17)

The livestock sector plays a dynamic role in the economic development of rural areas in Algeria. Due to its adaptation to harsh environments, goat breeding is practiced in many areas of the country. To ... [more ▼]

The livestock sector plays a dynamic role in the economic development of rural areas in Algeria. Due to its adaptation to harsh environments, goat breeding is practiced in many areas of the country. To the north, it is confined to mountainous areas, but the bulk of the workforce is left in the steppe and semi-desert areas. The goat population in Algeria reached 3.8 million heads, ranking second after sheep. The present work contributes to a better characterisation of local goat in Kabylie for production and reproduction traits. The study was conducted in the regions of Chemini (Bejaia province) and Bouzeguene (Tizi-Ouzou province). A survey was conducted in 29 herds. The results revealed that the overall mean of goats per households was 6.69 ± 2.97. The purposes of keeping goat in Chemini and Bouzguene was private consumption of milk (82.76%) and meat (68.97%) as well as for commercial exchange (62.07%). The Kabyle goat is small (male: 62.23 cm and female: 58.41 cm) with long hair. Its ears are drooping, its convex profile has a slightly pronounced nasal split and its coat colour ranges from dark brown to black. However, the crossbreeding with exotic breeds (mainly with Saanen goat), controlled or uncontrolled, increased the frequency of white coat. The average age at puberty in males was 6.93 ± 1.04 and 7.38 ± 0.94 months in females. The reported age at first kidding and kidding interval were 13.03 ± 0.87 months and 7.83 ± 1.29 months, respectively. [less ▲]

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See detailVascular endothelial growth factor: a blood biomarker in canine idiopathic pulmonary fibrosis.
Roels, Elodie ULg; Krafft, Emilie ULg; Laurila, HP et al

Poster (2014, October 17)

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See detailImpact of aging technique and muscle on oxidative stability of beef packaged under high-oxygen atmosphere
Didimo Imazaki, Pedro Henrique ULg; Tahiri, Assia ULg; Thimister, Jacqueline ULg et al

Poster (2014, October 17)

Two common approaches for beef aging are wet-aging and carcass-aging. Wet-aging refers to meat aged in a sealed vacuum package at refrigerated temperatures, while carcass aged at controlled temperatures ... [more ▼]

Two common approaches for beef aging are wet-aging and carcass-aging. Wet-aging refers to meat aged in a sealed vacuum package at refrigerated temperatures, while carcass aged at controlled temperatures and humidity is defined as carcass-aging. Carcass-aging is an ancient process used nowadays to produce beef characterized by its superior quality. The meat conservability is influenced by its sensitivity to oxidative process which can vary from one muscle to another. The aim of this study was to compare the effect of aging technique (wet-aging vs. carcass-aging), muscle (longissimus dorsi vs. rectus femoris) and previous vacuum storage time on colour and lipid stability of beef packaged in high-oxygen atmosphere. After a seven-day wet- or carcass-aging step, longissimus dorsi and rectus femoris muscle cuts from 4 Belgian Blue cows were vacuum packaged and stored at −1 °C for up to 28 days. At different times, part of these samples was repackaged under modified atmosphere – 70 % O2:30 % CO2 –, and stored during 7 days at +4 °C in order to simulate retail conditions. The following parameters were evaluated: colour (CIE L*a*b*), metmyoglobin %, lipid oxidation (TBARS), antioxidant enzyme activities (catalase, glutathione peroxidase and superoxide dismutase), alpha-tocopherol and fat content. The sensitivity of high-oxygen atmosphere repacked meat cuts to oxidation was influenced by the aging technique (wet > carcass conditions), muscle (rectus femoris > longissimus dorsi) and length of the vacuum storage. Oxidation stability could be associated with muscle catalase activity, and no association could be established with the alpha-tocopherol content. [less ▲]

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See detailIn vitro study of coinfection/superinfection parameters which can influence recombination events in noroviruses
Di Felice, Elisabetta; Ceci, Chiara; Toffoli, Barbara et al

Poster (2014, October 17)

Noroviruses (NoVs) are non-enveloped, single-stranded, positive-sense RNA viruses. They are important causes of acute non-bacterial gastroenteritis in humans worldwide but their study is currently yet ... [more ▼]

Noroviruses (NoVs) are non-enveloped, single-stranded, positive-sense RNA viruses. They are important causes of acute non-bacterial gastroenteritis in humans worldwide but their study is currently yet hampered by the lack of a cell culture system. NoVs genetically evolve by both point mutations and recombination and the murine norovirus (MuNoV) is considered as the best model for human NoVs. The aim of this study was to develop an experimental model based on the MuNoV in order to investigate coinfection/superinfection parameters that could impact recombination events. Monolayers of RAW264.7 cells were coinfected or superinfected with two MuNoV strains (CW1 and WU20) using different multiplicity of infection (0.1/1; 1/1 and 10/1 for CW1 and Wu20 , respectively) and time delays (0h; 0.5h; 1h; 2h; 4h; 8h; 12h and 24h) for infection. Supernatants were collected at 24 and 48 hours post-infection. Genomic copies of both viruses were first quantified by RT-QPCR. Then, viruses from the supernatants were plaque purified (36 clones per condition) and their recombinant status was checked by a real-time PCR discriminating method using primers targeting both extremity of the MuNoV genome. Results of quantitative and plaque picking assays are compared. Together, the results confirm that recombination does not frequently occur, at least in vitro and raise the issue on why these events are however so usual with in silico detection methods. The data also showed that superinfection exclusion seems to be triggered from 4h post infection with the first MuNoV. The mechanisms of the later should be still studied. [less ▲]

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See detailEvaluation of morphological and functional characteristics of Carnobacterium maltaromaticum isolated from vacuum-packaged beef with long shelf life
Didimo Imazaki, Pedro Henrique ULg; Tahiri, Assia ULg; Ndedi Ekolo, François ULg et al

Poster (2014, October 17)

Carnobacterium maltaromaticum is a lactic acid bacterium, and many lactic acid bacteria associated with meat are known for their bactericidal or bacteriostatic activity against other strains, species or ... [more ▼]

Carnobacterium maltaromaticum is a lactic acid bacterium, and many lactic acid bacteria associated with meat are known for their bactericidal or bacteriostatic activity against other strains, species or genera of bacteria. The presence of certain lactic acid bacteria adapted to a low temperature in fresh meat could extend the shelf life and improve the microbial stability and safety of this product. The aim of this study was to perform a morphological and functional characterization of a C. maltaromaticum strain with a potential bioprotective effect isolated from vacuum packaged beef with very long shelf life. The morphological, biochemical and enzymatic profiles, the influence of different temperatures and atmospheres, and the microbial stability of fresh beef inoculated with the C. maltaromaticum strain were evaluated. The isolated C. maltaromaticum strain presented similar morphological, biochemical and enzymatic profiles as those of two reference strains (LMG 11393 and LMG 22902). Among the studied conditions, a temperature of +12 °C and an atmosphere poor in oxygen were optimal for the growth of C. maltaromaticum. Vacuum packing is therefore suitable for this bacterium. An antimicrobial effect against Enterobacteriaceae was highlighted on inoculated fresh meat stored under N2. The functional characterization of this isolate will be further pursued by a genotypic characterization. Special attention will be taken to study its bioprotective properties. [less ▲]

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See detailEffect of bovine colostrum on growth and survival in Red kids during the first year of life.
Abdou, Harouna ULg; Marichatou, Hamani; Beckers, Jean-François ULg et al

Poster (2014, October 17)

The aim of this work was to measure the effect of supplementation with bovine colostrum among newborn Red goats breastfed in breeding conditions for semi-intensive type of Niger. The study was conducted ... [more ▼]

The aim of this work was to measure the effect of supplementation with bovine colostrum among newborn Red goats breastfed in breeding conditions for semi-intensive type of Niger. The study was conducted in Secondary Goat Breeding Center of Maradi (SGBCM). Forty newborn kids, regardless of sexe, were divided randomly into two groups: a "T-Control " group receiving only breast milk per feeding (n = 20) and a "C-Colostrum" group having the same diet but supplemented with bovine colostrum thawed (50 ml the first day of life, then 25 ml in 2 meals/ day between the ages of 2 and 15d, n = 20). The results indicate that supplementation with bovine colostrum in the first 15 days of life, increases the growth of kids until weaning (P<0.001), modifie some barymetric changes some settings improves health status and reduces the mortality rate. To our knowledge, in the studied environment, this work is original and seems to bring new knowledges likely to have practical applications in areas with farming conditions quite difficult. [less ▲]

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See detailAlveolar macrophages hyporeactivity act in the extreme susceptibility of DBA/2J to Influenza A infection.
Casanova Bustos, Tomas Ronaldo ULg; Garigliany, Mutien-Marie ULg; Desmecht, Daniel ULg

Poster (2014, October 17)

DBA/2J and C57BL/6J represent two opposite ends in terms of sensitivity and resistance to influenza A virus between the Mx-negative mouse lines. Several research teams focused on the factors explaining ... [more ▼]

DBA/2J and C57BL/6J represent two opposite ends in terms of sensitivity and resistance to influenza A virus between the Mx-negative mouse lines. Several research teams focused on the factors explaining this difference, mainly by genetic approaches using Recombinant Inbred Lines between those two strains. Several candidate-genes have been proposed, but it was not possible to determine their importance. To help to define the factors involved in the susceptibility of DBA/2J mice to influenza infection, we adopted a phenotypic approach to identify the critical steps of the infection process accounting for this extreme susceptibility. Overall, the data presented here support the role of a dysfunction of alveolar macrophages, to influenza infection in the higher susceptibility of DBA/2J mice to this virus. [less ▲]

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See detailFitness evolution of a recombinant murine norovirus during serial passages in cell culture
Oliveira-Filho, Edmilson; Di Felice, Elisabetta; Toffoli, Barbara et al

Poster (2014, October 17)

Human norovirus (NoV) infections are among the most important causes of gastroenteritis in both children and adults and often occur as outbreaks which may be foodborne. Recombination can dramatically ... [more ▼]

Human norovirus (NoV) infections are among the most important causes of gastroenteritis in both children and adults and often occur as outbreaks which may be foodborne. Recombination can dramatically change virulence properties of the viruses and has been often evidenced in silico for different NoV strains. Recently, after in vitro coinfection of RAW264.7 cells with parental murine norovirus (MuNoV) strains CW1 and Wu20, we obtained a recombinant Wu20/CW1 strain (Mathijs et al., 2010). This recombinant strain showed reduced plaque size compared to the parental strains. The aim of the study was to observe and molecularly characterize the natural genetic evolution of the recombinant MuNoV strain across in vitro replications. The recombinant strain was serially replicated in vitro (up to 14 passages). Viral plaque diameters of early and late progenies were compared with the Image software. A significant difference was shown between them with the Mann and Whitney non parametric statistical test. The average size of plaques increased from the earlier to the later progenies (from 0.1 mm2 to around 0.5 mm2). Molecular investigations are currently performed in order to specify in which genetic region mutations occur and whether or not this could explain fitness modifications during in vitro evolution. In addition two other parameters of in vitro virulence modification will be investigated (i) virus production and (ii) one step growth kinetics. The data should provide interesting information about genetic evolution in the genus Norovirus, especially regarding recombination events and explain how a recombinant strain, first disadvantaged compared to its parental strains, could regain fitness by genetic evolution. Mathijs, E., Muylkens, B., Mauroy, A., Ziant, D., Delwiche, T., Thiry, E., 2010. Experimental evidence of recombination in murine noroviruses. J Gen Virol 91, 2723-2733. [less ▲]

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See detailThe Effect of Urtica dioica Supplements on Egg Quality
Touazi, Leghel; Moula, Nassim ULg

Poster (2014, October 17)

Eggs are a rich source of lipids and proteins. Because of their low production cost, they represent a cheap source of animal proteins and lipids. recently, in Algeria, consumers’ interest are oriented of ... [more ▼]

Eggs are a rich source of lipids and proteins. Because of their low production cost, they represent a cheap source of animal proteins and lipids. recently, in Algeria, consumers’ interest are oriented of healthiness and dietetic values food. The purpose of this study was to investigate the effects a dietary supplement of Urtica dioica on laying hen's performance and egg quality. The study was conducted from may to june 2014 in the area of Chemini (Algeria). Sixty, 25-wk-old Lohmann Brown layers were randomly divided into 3 groups with 20 hens in each group. Group 1 was the control group fed a standard commercial diet based on corn and soybean, whereas the groups 2 and 3 were fed the control diet supplemented with 1% and 1.5% of nettle respectively. The hens were housed in cages in the same local and fed ad libitum. Fifty five eggs were sampled 4 times in each group from 25 to 27 weeks. A total of 220 eggs were examined. A series of measurements were carried out on each egg, namely egg weight, form index (egg shape), yolk to albumen ratio (Y:A), Yolk color, egg shell thickness, Haugh’s units. Egg weight, yolk color and Haugh Units (HU) were affected by age. Significant differences (P<0.05) were recorded between feeding type in total egg weight, yolk color and Haugh Units. The egg from group 2 proved to have a higher egg weight (57.67g; group 1: 55.41g; group 3: 56.70g; P<0.05), (33.4%), intermediate Yolk color (8.53; group 1: 9.03 ; group 3: 9.38; P<0.05) and HU (79.81; group 1: 80.85; group 3: 76.92). The results showed that the use of 1% and 1.5% of Urtica dioica, had positive effects on the color of yolk of laying hens. Using different levels of Urtica dioica could change the characteristics of egg and could meet the preferences of consumers for the intense color of the yolk. [less ▲]

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See detailEffet de l'expertise musicale sur la perception de la justesse vocale
Gosselin, Laura; Morsomme, Dominique ULg; Larrouy, Pauline ULg

Poster (2014, October 17)

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See detailEffect of biocides on murine norovirus and feline calicivirus, surrogates of human norovirus, in suspension, glove and stainless steel disc tests
Zonta, William ULg; Mauroy, Axel ULg; Thiry, Etienne ULg

Poster (2014, October 17)

Human noroviruses (HuNoV) are one of the major agents of human gastroenteritis and transmission occurs mainly by the faecal-oral route. The purpose of this work was to test biocide products on surrogate ... [more ▼]

Human noroviruses (HuNoV) are one of the major agents of human gastroenteritis and transmission occurs mainly by the faecal-oral route. The purpose of this work was to test biocide products on surrogate viruses of HuNoV in order to get information on the residual viral infectivity and on the integrity of viral genomes after biocide treatment in various conditions. Murine norovirus (MNN) and feline calicivirus (FCV) have been chosen as HuNoV surrogates because presenting comparable structure and physico-chemical properties. Two biocide products have been chosen, Ethanol (70%) and Kenocid 2100® (Peracetic acid and hydrogen peroxide) and used in 3 different conditions (in suspension, on gloves and on stainless steel discs). The biocide product was tested according to Afnor norm EN 14476. The reduction of viral titre was inferred and RNA extraction followed by a 1 step RT-qPCR was performed. If biocides products tested are able to show a 4 log reduction of the viral infectious titre, they are considered as effective. Efficacy against HuNoV can be extrapolated from these results. MNV is sensitive to Ethanol and Kenocid 2100® with and without any effect on genomic copy numbers respectively. FCV is sensitive to Kenocid 2100® with an effect on genomic copy numbers but is resistant to EtOH. The absence of effect of Kenocid 2100® on genomic copy numbers of MNV indicates this biocide product does not interfere directly on the viral genome. It may likely act on the viral structure, the capsid for example. This project is financed by Federal Public Service, Health, Food Chain Safety and Environment, in Belgium (RT 10/6 TRAVIFOOD). [less ▲]

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See detailL'intolérance environnementale idiopathique attribuée aux champs électromagnétiques (IEI-EMF)
Demaret, Isabelle ULg

Poster (2014, October 16)

Depuis le début des années '80, des chercheurs étudient les plaintes des personnes se disant hypersensibles aux champs électromagnétiques (EMF), sous les normes recommandées. Les recherches n'ont ... [more ▼]

Depuis le début des années '80, des chercheurs étudient les plaintes des personnes se disant hypersensibles aux champs électromagnétiques (EMF), sous les normes recommandées. Les recherches n'ont cependant pas démontré que ces personnes étaient capables de détecter les EMF ni qu'elles présentaient des changements physiologiques en étant exposées aux EMF . L'OMS a regroupé ces plaintes sous le nom d'Intolérance Environnementale Idiopathique attribuée aux Champs Electromagnétiques (IEI-EMF). Au niveau médical, l'IEI-EMF est classée parmi les syndromes fonctionnels somatiques comme d'autres syndromes sans bases physiologiques démontrées. [less ▲]

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See detailQuantitative Texture Analysis of melt-cast processed Bi-2212 superconductors
Dellicour, Aline ULg; Vertruyen, Bénédicte ULg; Chateigner, Daniel et al

Poster (2014, October 15)

Bi2Sr2CaCu2O8+δ HTSC superconductor is characterized by a very strong normal-state resistivity anisotropy, with ρc/ρab typically above 104. The aim of this study is to use Quantitative Texture Analysis ... [more ▼]

Bi2Sr2CaCu2O8+δ HTSC superconductor is characterized by a very strong normal-state resistivity anisotropy, with ρc/ρab typically above 104. The aim of this study is to use Quantitative Texture Analysis from neutron diffraction measurements to estimate the orientation effect on the macroscopic resistivity (ρM) in melt-cast bulk Bi2Sr2CaCu2O8+δ superconductors. Our approach uses the geometric mean (GMA) [1] of the single crystal resistivity tensor (ρSC) weighted by the Orientation Distribution Function (ODF) to quantitatively estimate the macroscopic resistivity tensor of the samples. The ODF is obtained from neutron Combined Analysis [2], using the E-WIMV algorithm of the MAUD software. The GMA applies to the rank-two resistivity tensor of the orthorhombic space group considered tetragonal due to the small difference of a- and b-axes of the phase, with only two independent tensor components. We relate a relatively good agreement between measured and calculated macroscopic resistivity ratios. [less ▲]

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See detailIncrease in northern hemisphere stratospheric hydrogen chloride over recent years
Mahieu, Emmanuel ULg; Chipperfield, MP; Notholt, J et al

Poster (2014, October 07)

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See detailPotential Proteomic Biomarkers Associated To Mucosal Healing In Crohn’s Disease
MEUWIS, Marie-Alice ULg; Baiwir, Dominique ULg; Mazzucchelli, Gabriel ULg et al

Poster (2014, October 06)

Introduction and objectives: In Crohn's disease (CD), there is a discrepancy between clinical activity of the disease (symptoms) and intestinal healing. However absence of tissue healing is associated ... [more ▼]

Introduction and objectives: In Crohn's disease (CD), there is a discrepancy between clinical activity of the disease (symptoms) and intestinal healing. However absence of tissue healing is associated with the risk of relapse and tissue damage progression. Endoscopy is costly and invasive. Hence biomarkers correlating with intestinal healing could improve disease management. We aimed to identify potential biomarkers associated to CD mucosal healing by a shotgun proteomics label free study. Methods: We used the STORI clinical trial cohort (n=103) aiming at identifying markers associated to relapse prediction after Infliximab treatment withdrawals. We used serum samples of patients in clinical remission, grouped according to the degree of intestinal healing seen at endoscopy. We performed depletion of the 20 most abundant plasma proteins on each serum pools and ran a proteomics label free differential analysis using 2D-nanoUPLC-MSE HDMS Synapt G1 for data acquisition and Protein Lynks Global Server vs 2.4 for data analysis (Waters, Corp., Milford, USA). Results and Discussion: We obtained potential biomarkers and designed a multiplexed -selected reaction monitoring (SRM) method for validation of these candidates in each individual patient. The method may also be tested in an independent set of IBD patients with and without mucosal healing. Conclusions: This research strategy and results of SRM validation of potential biomarkers associated to mucosal healing in this cohort of CD patients as well as the tests done on other CD patients, may provide new opportunities for CD follow-up tests development. [less ▲]

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See detailSolar irradiance modelling over Belgium using Regional Climate Models within the frame of a day-ahead photovoltaic production forecasting system
Beaumet, Julien ULg; Doutreloup, Sébastien ULg; Fettweis, Xavier ULg et al

Poster (2014, October 06)

WRF-ARW and MAR climate models performances for the modelling of solar irradiances over Belgium are evaluated using in-situ measurements at Sart-Tilman and Daussoulx. Different WRF-ARW settings are tested ... [more ▼]

WRF-ARW and MAR climate models performances for the modelling of solar irradiances over Belgium are evaluated using in-situ measurements at Sart-Tilman and Daussoulx. Different WRF-ARW settings are tested. Sigmoid model proposed by Ruis-Ariaz etal. (2010) is used to decompose solar irradiance into direct and diffuse fraction. The performance of this model using measured and modelled global irradiances is also evaluated. [less ▲]

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See detailNear-Death Experiences in patients with locked-in syndrome
Charland-Verville, Vanessa ULg; Lugo Ramirez, Zulay del Rosario ULg; Jourdan, Jean-Pierre et al

Poster (2014, October 04)

Near-Death Experiences (NDEs) are classically associated with positive emotions like peacefulness, happiness and joy [1-3]. To date, few negative NDEs reports have been documented [4]. Although NDEs ... [more ▼]

Near-Death Experiences (NDEs) are classically associated with positive emotions like peacefulness, happiness and joy [1-3]. To date, few negative NDEs reports have been documented [4]. Although NDEs classically arise in the context of an acute severe brain damage, their associated memories are reported as being phenomenologically very rich and detailed [5]. To date, no satisfactory explanatory model exits to fully account for the rich phenomenology of NDEs following a severe acute brain injury [6]. Neurobiological hypotheses include cerebral hypoxia [7, 8] and temporal lobe dysfunctions [9] to account for some of the features occurring during NDEs. However, it has been recently shown that anoxic/hypoxic, traumatic and other supratentorial brain lesions do not seem to influence the content of a NDE when assessed with a standardized tool (i.e., Greyson NDE scale; [1]). Due to their particular brain lesion (i.e., pontine brainstem), locked-in syndrome (LIS) patients provide a unique opportunity to further investigate the neural correlates of NDEs. We here aimed at retrospectively characterizing the content of NDEs in patients with LIS having suffered from an acute brainstem lesion (cerebrovascular accident (CVA) or trauma; i.e., “LIS NDEs”) and to compare these experiences to those collected in a cohort of matched NDE experiencers after coma with supratentorial lesions (CVA or trauma; i.e., “classical NDEs”). [less ▲]

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See detailStudy of sex ratio and morphotypes of the Multicoloured Asian Ladybird, Harmonia axyridis Pallas in Belgian maize
Vandereycken, Axel ULg; Fassotte, Bérénice ULg; Barsics, Fanny ULg et al

Poster (2014, October)

Several insect species are known to have different morphotypes, an adaptation to heterogeneities in changing environments. This phenotypic plasticity could be a factor used by the Multicoloured Asian ... [more ▼]

Several insect species are known to have different morphotypes, an adaptation to heterogeneities in changing environments. This phenotypic plasticity could be a factor used by the Multicoloured Asian Ladybird, which is considered as an invasive species in Europe since its introduction in the 80’s. Harmonia axyridis has four major morphotypes: 2 melanic forms, conspicua and spectabilis; and 2 non-melanic, succinea and axyridis. In Belgium, only the three first are observed. Literature reports variations in morphotype frequencies, across native and introduced strains. These variations seem to be linked to climate (geographical and seasonal variation), with non-melanic forms being the most abundant in hot and arid climate. This study focused on the variation of morphotype abundance in H. axyridis according to season, field and gender. Adult ladybirds were caught from mid-July to mid-October 2012 into 5 maize fields. The proportions of observed morphotypes were compared according to the sampling season. The abundance of morphotypes was not significantly different through the fields; the observed ratios were 81.6%, 15% and 3.4% for succinea, spectabilis and conspicua respectively. Succinea was the most observed morphotype (χ2=755.8; P<0.001). The total number of collected males and females was the same with ratios of 48.2% and 51.8%: (χ2=0.93; P=0.33). The sex ratio was also not significantly different for each morphotype. There was no evolution of melanic and non-melanic form ratio according to the season, with 25.6% of melanic form in summer and 20.6% in autumn (χ2=1.22; P=0.27). Our results seem to show that morphotype adaptation according to the climate is not observed for Belgian ladybirds. [less ▲]

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See detailTemplating calcium carbonate drug delivery carriers based on polyphosphoester copolymers
Ergül, Zeynep ULg; Debuigne, Antoine ULg; Calvignac, Brice et al

Poster (2014, October)

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See detailSinuso-nasal adenocarcinoma in a roe deer (Capreolus capreolus)
Volpe, Rosario ULg; Cassart, Dominique ULg; Neukermans, Axel et al

Poster (2014, October)

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See detailEmotional distress and family factors as predictors of quality of life in Children with Cystic Fibrosis
Toucheque, Malorie ULg

Poster (2014, October)

Background. Due to recently developed therapies, patients’ life expectancy with CF today is in the early 40s. As a result, medical providers in CF care centers seek not only to improve patients’ health ... [more ▼]

Background. Due to recently developed therapies, patients’ life expectancy with CF today is in the early 40s. As a result, medical providers in CF care centers seek not only to improve patients’ health but also to enhance their quality of life (QOL). QOL as a concept for children, in particular, is fairly new. Accordingly, QOL of school-aged children with CF is relatively under-investigated. In recent years, the role of family contextual variables has received increased attention as predictors of child adjustment to illness. Evidence exists that parenting and parent-child relationship factors are related to children’s emotional development and thus may be life-course determinants in their health. To date, no study has quantitatively investigated parental factors, particularly with respect to paternal variables, associated with the QOL of children with CF. Objective. The study aimed to investigate the relation of parenting stress, family functioning, and fathers’ involvement in the disease’s management to emotional distress and QOL in children with CF. Study design. Using a cross-sectional design, this study recruited families of children with CF from four different CF Centers. Data collection is on going and a full sample of 40 families is expected for this presentation. To date, the study protocol was completed by 18 families. Inclusion criteria for children include: (a) a diagnosis of CF for at least one year; and (b) age 8 to 12 years. Also, both parents must be willing to participate to be included in our sample. Children complete the State-Trait Anxiety Inventory for Children (STAIC), Children’s Depression Inventory (CDI-2), and Quality of Life Systemic Inventory for Children (QLSI-C). Parents complete the Parenting Stress Index – Short Form (PSI-4-SF), Family Environment Scale (FES), and Dad’s Active Disease Support (DADS) (i.e., a measure of paternal involvement in illness management). Results. With the full sample, we will run multiple regression analyses with STAIC, CDI, PSI-4-SF, FES and DADS as predictors of children’s QOL scores and run moderation and mediation analyses to examine the indirect effect of mothers and fathers’ variables on the child’s QOL. With the sample to date, QOL in children is significantly associated with state anxiety (r=.62; p=.007), trait anxiety (r=.76; p<.001), and depression (r=.77; p=.001). We also found a direct link between the mothers’ parenting stress levels and children’s QOL (r=.51; p=.031), anxiety (r=.49; p=.045), and depression (r=.47; p=.054). Fathers’ parenting stress levels (r=.54; p=.026) and mothers’ evaluation of fathers’ involvement (r=.47; p=.047) each are significantly associated with the mothers’ parenting stress. These results may be suggestive of a potential mediator effect. Conclusion. Information about fathers is underrepresented in pediatric psychology research. However, interest in impact of parental adaptation on children’s adjustment to chronic disease is on the increase. The results of this study are expected to contribute significantly to the understanding of how both parents play a role in the QOL and emotional adjustment of school-aged children with CF. [less ▲]

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See detailExperimental in vivo infection of pigs by a Belgian wild boar hepatitis E virus strain
Thiry, Damien ULg; Rose, Nicolas; Paboeuf, Frédéric et al

Poster (2014, October)

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See detailKnowing the past to anticipate the future: soil charcoal as a proxy to model forest evolution
Morin, Julie ULg; Biwolé, Achille; Bourland, Nils et al

Poster (2014, October)

Tropical forests of Central Africa constitute the second most important block of moist forest of the world. However little is known about their past evolution. Indeed, determining the past specific ... [more ▼]

Tropical forests of Central Africa constitute the second most important block of moist forest of the world. However little is known about their past evolution. Indeed, determining the past specific composition of these forests could allow modeling their evolution over time and providing data about their resilience capacity facing global change. To do this, we performed a pedoanthracological analysis in the semi-deciduous forests of southeastern Cameroon. We excavated test pits in 53 plots of botanical inventory along a gradient of vegetation, quantified wood charcoals by layers of 10 cm, identify the species present in charcoals, dated the charcoals by the radiocarbon method, then built up sequences including present forest composition. Results show that repeated fire events occurred across the study area during the last 2500 years. These disturbances are likely human-induced regarding evidence of anthropogenic activities (e.g. potsherds). Nonetheless the past specific composition does not strongly differ from the current one except for the oldest layers related to the major dry climatic event of 2500 BP. We conclude that moist forests have a good resilience capacity regarding moderate disturbances but were and will be deeply impacted by climate change. [less ▲]

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See detailHarmonia axyridis population study in agroecosystems
Vandereycken, Axel ULg; Fassotte, Bérénice ULg; Durieux, Delphine ULg et al

Poster (2014, October)

The Multicoloured Asian ladybird, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), is one of these species which was intentionally introduced for biological control and has spread from its native ... [more ▼]

The Multicoloured Asian ladybird, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), is one of these species which was intentionally introduced for biological control and has spread from its native range in Central and Eastern Asia to large parts of North and South America, Europe, and Africa. The decline of native species is linked to the spread and the aggressive behaviour of H. axyridis. From 2009, we evaluated the population densities of aphids predator and predator diversities, with a special focus on H. axyridis in agroecosystems of Wallonia (South of Belgium). First, field crops preferences of H. axyridis were determined. Later, changes linked to aphid’s predator populations over time were evaluated. Finally, H. axyridis population changes between two crop farming methods were also evaluated. Samplings performed in agroecosystems highlighted that the community of aphid's predator is composed of few dominant species: three coccinellids (Coccinella septempunctata L., P. quatuordecimpunctata L., and H. axyridis), one syrphid (Episyrphus balteatus De Geer), and one chrysopid (Chrysoperla carnea Stephens). We demonstrated that H. axyridis do not invade all crops at the same rate, maize and broad bean being more infested than wheat and potato at both larval and adult stages. Moreover, H. axyridis populations in maize have strongly increased from 2009 to 2011. Finally, we showed that organic farming do not contribute to increase the abundance of H. axyridis but leads to increase the total abundance of aphid’s natural enemies. [less ▲]

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See detailTSC2 and 14-3-3 proteins down-regulate a RIP3 dependent PDT-induced Necroptosis in Glioblastoma
Fettweis, Grégory ULg; Coupienne, Isabelle; Fillet, Marianne ULg et al

Poster (2014, October)

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See detailLe développement et la validation du processus de raisonnement clinique
Collard, Anne ULg; Bourguignon, Jean-Pierre ULg

Poster (2014, October)

Contexte : La Faculté de Médecine de l’Université de Liège propose dès la 2ème année de son cursus un enseignement de type PBL. Nous avons étudié le développement des capacités de raisonnement en lien ... [more ▼]

Contexte : La Faculté de Médecine de l’Université de Liège propose dès la 2ème année de son cursus un enseignement de type PBL. Nous avons étudié le développement des capacités de raisonnement en lien avec la base de connaissances et son utilisation. Méthodes : Le développement des capacités de raisonnement est étudié de façon transversale par l’utilisation d’un TCS ainsi que longitudinalement exploitant les résultats des évaluations certificatives de raisonnement. Les niveaux de certitude aux réponses correctes et incorrectes aux tests de connaissances sont utilisés pour calculer un indice d’auto-évaluation du champ des connaissances sous-jacentes au raisonnement. Par ailleurs, l’effet d’une consigne de validation du processus de raisonnement en cours de séance PBL a également été étudié. Résultats : La capacité de raisonnement est manifeste dès la 2ème année et augmente avec l’expérience. Elle est corrélée à la capacité d’auto-évaluation du champ des connaissances. De plus, la validation du processus de raisonnement peut être renforcée par une consigne explicite et favorise ainsi l’apprentissage du raisonnement. Conclusion : Ces résultats ont abouti à l’élaboration d’un modèle permettant de mettre en perspective les différents facteurs impliqués dans le processus d’apprentissage du raisonnement en lien avec la base de connaissances et son utilisation. [less ▲]

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See detailRasa3 catalytic activity controls Rap1 activation and integrin signaling during megakaryocyte differentiation in mouse.
Molina Ortiz, Patricia ULg

Poster (2014, October)

Rasa3 is a GTPase activating protein of the GAP1 family whiwh target Ras and Rap1. Rasa3 catalytic inactivation in mice (Rasa3-/-) results in early embryonic lethality. Here, we show that irradiated nude ... [more ▼]

Rasa3 is a GTPase activating protein of the GAP1 family whiwh target Ras and Rap1. Rasa3 catalytic inactivation in mice (Rasa3-/-) results in early embryonic lethality. Here, we show that irradiated nude mice reconstituted with Rasa3-/- hematopietic cells (SCID-Rasa3-/-) present a lethal syndrome characterized by severe defects during megakaryopoiesis, thrombocytopenia and a predistosition to preleukemia. These Rasa3-/- megakaryocites (MKs) have an increased active Rap1 and constitutive integrin activation, recapitulated in Rasa"+/- platelets, that leed to defects in migration, adhesion and differentiation into proplatelet forming megakaryocytes. [less ▲]

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See detailThe effect of deforestation rate on land tenure in Central AFrica
Gillet, Pauline ULg; Vermeulen, Cédric ULg; Feintrenie, Laurène

Poster (2014, October)

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See detailA propos de deux cas de manipulation de patients dans le cadre de recherches cliniques
Jamoulle, Marc ULg

Poster (2014, October)

L’exercice de la prévention quaternaire, soit veiller à ne pas nuire au patient, est mis ici à contribution dans deux cas de recherches cliniques. Deux patients ont vécu dans le même service de ... [more ▼]

L’exercice de la prévention quaternaire, soit veiller à ne pas nuire au patient, est mis ici à contribution dans deux cas de recherches cliniques. Deux patients ont vécu dans le même service de cardiologie une tentative de manipulation lors de recherches, l’une pharmacologique, l’autre de traitement invasif. Le questionnement des patients a été discutés au cours de la consultation de médecine générale. Les deux patients ont chacun relu et compris la portée de leur témoignage publié ci-dessous et marquent leur accord formel à leur publication. [less ▲]

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See detailThe cellobiose-sensor CebR is the gatekeeper of Streptomyces scabies pathogenicity
Jourdan, Samuel ULg; Francis, Isolde; Loria, Rosemary et al

Poster (2014, October)

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See detailHow snow affects air-sea ice CO2 fluxes
Delille, Bruno ULg; Kotovitch, Marie ULg; Van Der Linden, Fanny ULg et al

Poster (2014, October)

Sea ice is a significant contributor to the sink of atmospheric CO2 by polar oceans. Physical and biogeochemical sea ice processes affect partial pressure of CO2 within sea ice, that in turn controls the ... [more ▼]

Sea ice is a significant contributor to the sink of atmospheric CO2 by polar oceans. Physical and biogeochemical sea ice processes affect partial pressure of CO2 within sea ice, that in turn controls the way and magnitude of air-sea ice CO2 fluxes. Snow cover appears to affect the magnitude of the fluxes. In order to understand the role of snow, we compared chamber and micrometeorological measurements of air-ice CO2 fluxes over snow covered and uncovered sea ice (land fast and pack ice) in both arctic and antarctic. We observed significant differences between fluxes over uncovered and covered sea ice. In addition chamber and micrometeorological measurement show different patterns that are partially due to snow cover. By gathering these observations, we observed at least three effects of snow on air-ice CO2 fluxes. Snow appears to (i) act as transient CO2 reservoir (ii) affect thermal properties of the ice surface (iii) control gas transfer depending on snow structure (superimposed ice, slush). [less ▲]

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See detailDesigning large-scale CO2 capture units with assessment of solvent degradation
Léonard, Grégoire ULg; Crosset, Cyril; Dumont, Marie-Noëlle ULg et al

Poster (2014, October)

Solvent degradation is a major drawback for the large-scale implementation of post-combustion CO2 capture due to amine consumption and emission of degradation products. In the present work, we refine a ... [more ▼]

Solvent degradation is a major drawback for the large-scale implementation of post-combustion CO2 capture due to amine consumption and emission of degradation products. In the present work, we refine a previous kinetic model for describing solvent oxidative and thermal degradation based on experimental results. The CO2 capture process is then modeled in Aspen Plus with assessment of solvent degradation. As a result, this work provides a useful tool for the identification of optimal operating conditions that minimize both the energy and environmental impacts of the process. [less ▲]

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Peer Reviewed
See detailAdherence to Continuous Positive Airway Pressure (CPAP) Therapy
Deflandre, Eric ULg; Degey, Stéphanie; BONHOMME, Vincent ULg et al

Poster (2014, October)

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See detailRegioselective labeling of Nanofitin by using a phosphorylated peptide tag
Goux, Marine ULg

Poster (2014, October)

Recently, new strategies emerged in the field of monoclonal antibodies radiolabeling for PET imaging with the use of positron emitter such as zirconium-89 or gallium-68. Despite their important role in ... [more ▼]

Recently, new strategies emerged in the field of monoclonal antibodies radiolabeling for PET imaging with the use of positron emitter such as zirconium-89 or gallium-68. Despite their important role in the therapeutic world, antibodies have many disadvantages related to their structure. Moreover, conjugation of chelating agent often occurs on lysines, which is non-regioselective and leads to a heterogeneous mixture of products. In addition, the slow clearance of antibodies can be a problem to obtain a good contrast when they are used in imaging. To address these different limitations, we developed a chemistry-free chelating system consisting of a highly phosphorylatable peptide tag. A specific phosphorylation step, with the alpha subunit of the casein kinase II, generates a nanocluster of 4 phosphates that can interact strongly with metal ion like zirconium. This strategy has already demonstrated its powerfulness for the stable and specific anchoring of protein on zirconium phosphonate-based microarray [1]. We are now adapting the use of this labeling tag to the stereoselective chelation of radionuclides for PET imaging. As described previously, functionalizing the tag with a phosphate nanocluster is a key step to provide the capacity to specifically chelate metal ions such as zirconium or gallium. In order to optimize the sequence of the phosphorylatable tag, we have used mimetic peptides with different phosphorylation states (from 0 to 4 phospho-serine). We have shown the complexation between the phosphorylatable tag and a lanthanide: terbium(III). With a competition study between terbium(III) and zirconium(IV), we showed that the peptide tag preferably chelate zirconium with an affinity in the micromolar range. Considering this tag has been created to specifically anchoring protein on zirconium phosphonate-based microarray, it is possible that the sequence is not optimized for our application. In order to increase the affinity from micromolar to nanomolar, we are currently working on a sequence derived from calcium-binding proteins to chelate specifically lanthanides[2]. As described by Pardoux et al.[3], our strategy is to functionalize this sequence with a phosphate nanocluster able to chelate zirconium or gallium. Our first results shown that a mono-phosphorylatable tag phosphorylated in vitro is able to chelate terbium(III) with a lower affinity than the wild type. Considering that terbium(III) is bigger than gallium(III) or zirconium(IV), we can suppose that the cage obtained is too small but suitable for other ions. In order to validate our hypothesis, we have planned to radiolabel those tags and determine their affinity for gallium(III). [1] M. Cinier, M. Petit, F. Pecorari, D. R. Talham, B. Bujoli, and C. Tellier, “Engineering of a phosphorylatable tag for specific protein binding on zirconium phosphonate based microarrays.,” J. Biol. Inorg. Chem., vol. 17, no. 3, pp. 399–407, Mar. 2012. [2] L. J. Martin, “Development of Lanthanide-Binding Tags (LBTs) as powerful and versatile peptides for use in studies of proteins and protein interactions,” 2008. [3] R. Pardoux, S. Sauge-merle, D. Lemaire, P. Delangle, L. Guilloreau, J. Adriano, and C. Berthomieu, “Modulating Uranium Binding Affinity in Engineered Calmodulin EF-Hand Peptides : Effect of Phosphorylation,” PLoS One, vol. 7, no. 8, 2012. [less ▲]

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Peer Reviewed
See detailAdherence to Continuous Positive Airway Pressure (CPAP) Therapy
Deflandre, Eric ULg; Degey, Stéphanie; BONHOMME, Vincent ULg et al

Poster (2014, October)

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See detailCharacterization of stream - aquifer interaction in carbonate rocks
Briers, Pierre ULg; Sohier, Catherine ULg; Schmit, Flore et al

Poster (2014, September 30)

Groundwater - surface water interactions play a fundamental role in terms of quantity and quality of water and in terms of ecological quality of rivers. Despite many research efforts and the necessity to ... [more ▼]

Groundwater - surface water interactions play a fundamental role in terms of quantity and quality of water and in terms of ecological quality of rivers. Despite many research efforts and the necessity to better understand such interactions in order to reach effective management of water resources, stream-aquifer exchanges remain poorly understood, in particular in fractured carbonate environments. [less ▲]

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Peer Reviewed
See detailFrench good practice guidelines for the management of the low back pain risk among workers exposed to manual handling
Petit, Audrey; Mairiaux, Philippe ULg; FASSIER, Jean-Baptiste et al

Poster (2014, September 29)

Background Manual handling of loads (MHL) is a widespread practice in the workplace and is the leading cause of work accidents. In particular, MHL is associated with a risk of low back injuries which can ... [more ▼]

Background Manual handling of loads (MHL) is a widespread practice in the workplace and is the leading cause of work accidents. In particular, MHL is associated with a risk of low back injuries which can compromise staying at work and worker's career in the case of recurrence or chronicity. This communication aims to set forth the French occupational Guidelines for the management of the low back pain (LBP) risk among workers exposed to MHL, published in October 2013. Methods These Good Practice Guidelines were written according to the Clinical Practice Guidelines method proposed by the French National Authority for Health. They emanated from a synthesis of the literature by a multidisciplinary working party of 24 experts and were peer reviewed by a committee of 50 experts. These Guidelines are designed to define the components of an appropriate surveillance program for all workers exposed to MHL activities at the workplace and especially suffering from LBP and still at work, or suffering LBP and on sick leave. Results Because of the potential impact on workers’ fears and beliefs, the information provided by the various actors must be consistent, or even reassuring in relation to the prognosis of LBP. Among LBP workers, it is recommended to look for signs of severity or an underlying disease at the acute, subacute and chronic stages of LBP; to encourage continuation or resumption of physical activity; situate the current episode of LBP in the worker’s work history (recent changes of working conditions) and evaluate the impact of LBP on the worker’s job. In the case of persistent or recurrent LBP, it is recommended to evaluate biopsychosocial and socioeconomic risk factors likely to influence chronicity, prolonged incapacity and delay return to work. If workers are on prolonged and/or repeated sick leave for LBP, a pre-return-to-work visit is recommended to evaluate the pain and functional disability and their repercussions, as well as the main factors of prolonged work incapacity; encourage and help the worker to develop a return to work dynamic; identify the main difficulties related to work and possible job adjustments and evaluate the need to initiate a job staying at work approach. Conclusions Primary, secondary and tertiary prevention are necessary for the management of low back pain at work. [less ▲]

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See detailFITNESS EVALUATION OF A RECOMBINANT MURINE NOROVIRUS DURING SERIAL PASSAGES IN CELL CULTURE
Oliveira-Filho, Edmilson; Di Felice, Elisabetta; Toffoli, Barbara et al

Poster (2014, September 28)

Noroviruses are single stranded positive sense RNA viruses which can infect human and different animal species. Human norovirus (NoV) infections are among the most important causes of gastroenteritis in ... [more ▼]

Noroviruses are single stranded positive sense RNA viruses which can infect human and different animal species. Human norovirus (NoV) infections are among the most important causes of gastroenteritis in both children and adults. Infections often occur as outbreaks which may be foodborne. Due to the lack of an efficient cell culture system as well as a workable animal model, many aspects of the NoV infection in human are still poorly understood. The murine norovirus (MuNoV) grows easily in cell culture in contrast to the Human NoV, and constitutes an excellent animal model. Recombination can dramatically change virulence properties of the viruses and has been evidenced in silico for different human NoV strains isolated from clinical cases. Recently, after in vitro coinfection of RAW264.7 cells with parental MuNoV strains CW1 and Wu20, we obtained a recombinant Wu20/CW1 strain. This recombinant strain showed reduced plaque size compared to the parental strains. The aim of the study was to observe and molecularly characterize the natural genetic evolution of the recombinant MuNoV strain across in vitro replications. Viral fitness is a complex concept. Here we defined this fitness as the ability of a viral population to adapt to the cell culture system. Thus, the recombinant strain was serially replicated in vitro in RAW264.7 cells (up to 14 passages). Viral plaque sizes of early and late progenies were compared with the Image J software. A significant difference was shown between them with the Mann and Whitney non parametric statistical test. Afterwards, viruses from different cell passages were cloned and sequenced. The average plaque size increased from the earlier to the later progenies (from 0.1 mm2 to around 0.5 mm2). Molecular investigations are currently performed in order to specify in which genetic region mutations occur and whether or not this could explain fitness modifications during in vitro evolution. In addition, two other parameters of in vitro virulence modification will be investigated: (i) virus production and (ii) one step growth kinetics. The data should provide interesting information about genetic evolution in the genus Norovirus, especially regarding recombination events and explain how a recombinant strain, first disadvantaged compared to its parental strains, could regain fitness by genetic evolution. [less ▲]

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See detailLe secret des crèmes foisonnées
Petrut, Raul Flaviu ULg; Danthine, Sabine ULg; Blecker, Christophe ULg

Poster (2014, September 26)

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See detailHDAC5 Depletion in Cancer Cells Induces an Oxidative Stress and Leads to a Metabolic Reprogramming toward Glucose and Glutamine Metabolism
Hendrick, Elodie ULg; Peixoto, Paul ULg; Polese, Catherine ULg et al

Poster (2014, September 25)

Histone deacetylases (HDAC) is a family of eighteen enzymes, which modulates the acetylation level of histones and non-histone proteins to regulate gene expression and chromatin structure. Broad-spectrum ... [more ▼]

Histone deacetylases (HDAC) is a family of eighteen enzymes, which modulates the acetylation level of histones and non-histone proteins to regulate gene expression and chromatin structure. Broad-spectrum inhibitors of these enzymes such as SAHA can inhibit tumor growth both in vitro and in vivo and are currently used as anti-cancer agents in clinic. For many years, we are investigating the specific role of individual HDAC members in cancer biology and we have recently demonstrated that specific depletion of HDAC5 using siRNA technology reduced cancer cells proliferation and survival1 The goal of this study is to further understand the molecular mechanisms of action of HDAC5 in cancer cells. Screening transcriptomic study demonstrated that HDAC5 depletion induces a down-regulation of subunits of the complex I of the mitochondrial respiratory chain (NDUFB5-NDUFA3) as well as anti-oxydant proteins (Ferritin, Metalothionein,¿) through modulation of mRNA stability. Therefore, HDAC5 depletion causes a significant increase of ROS production inducing both apoptosis and mechanisms of mitochondria quality control (mitophagy and mitobiogenesis). This HDAC5 depletion-induced mitochondrial dysfunction provokes metabolic adaptation associated with increased importance of glycolysis and glucose. Indeed, interference with glucose supply in HDAC5-depleted cancer cells significantly increases apoptotic cell death suggesting that glucose deprivation might be combined to HDAC5 inhibition as a therapeutic strategy to kill cancer cells. Our study demonstrated for the first time that specific HDAC5 inhibition induces metabolic reprogramming and provides insight into a valuable experimental strategy for manipulation of specific HDAC5 inhibition and glucose metabolism in therapy against cancer. 1.Peixoto, P. et al. HDAC5 is required for maintenance of pericentric heterochromatin, and controls cell-cycle progression and survival of human cancer cells. Cell death and differentiation, 2012; 1-14. Presenting author e-mail: elodie.hendrick@student.ulg.ac.be [less ▲]

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See detailCarbon balance of a grazed pasture and its response to grazing management
Jerome, Elisabeth ULg; Gourlez de la Motte, Louis ULg; Beckers, Yves et al

Poster (2014, September 24)

The C balance of a grazed pasture situated in Condroz (Wallonia) and its dependence on climatic conditions and grazing management were investigated on the basis of eddy covariance measurements and ... [more ▼]

The C balance of a grazed pasture situated in Condroz (Wallonia) and its dependence on climatic conditions and grazing management were investigated on the basis of eddy covariance measurements and horizontal C flow estimates. In average on three years, NEE was +43±24 gCm-2yr-1 and NBP was +7±26 gCm-2yr-1, suggesting that that the site is C neutral. Management by the farmer (organic fertilization), but also climate conditions influencing management (feed supplements), were the main factors impacting the C balance inter-annual variability. At a daily and seasonal scale, grazing impact on CO2 fluxes did not appear explicitly, being blurred by flux response to climate drivers. It was highlighted by specific investigations. The indirect grazing impact (photosynthesizing biomass consumption, excretions, soil compaction) was deduced from an analysis of the flux to PPFD response evolution during grazing period; the direct impact (livestock respiration) was investigated through confinement experiments. Result showed that saturation GPP changes were negatively correlated to grazing intensity (product of the stocking rate and grazing duration). On the contrary, no significant change in TER was observed. The direct impact of grazing due to cattle respiration was estimated to 2.59±0.58 kgCLU-1day-1, i.e. 8% of the TER. [less ▲]

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See detailImportance des modèles de distribution de niche potentielle dans la gestion des espèces tropicales exploitées: cas des taxons du genre Guibourtia Benn
Tosso, Dji-ndé Félicien ULg; Daïnou, Kasso ULg; Hambuckers, Alain ULg et al

Poster (2014, September 24)

De la famille des (Fabaceae / Caesalpinioideae) et composé de 13 espèces en Afrique, le genre Guibourtia comporte des taxons à forte valeur culturelle et à forte valeur commerciale. Aujourd'hui, la ... [more ▼]

De la famille des (Fabaceae / Caesalpinioideae) et composé de 13 espèces en Afrique, le genre Guibourtia comporte des taxons à forte valeur culturelle et à forte valeur commerciale. Aujourd'hui, la pression de l'exploitation combinée aux faibles densités de ce genre, fait a priori peser d’importantes menaces sur certaines de ses populations. Un projet de recherche a donc été initié afin de mieux comprendre la structure et la diversité génétique des populations de Guibourtia, en lien avec l'exploitation forestière et les patrons de reproduction spécifiques. Un premier volet de la recherche a consisté à identifier les déterminants climatiques expliquant la distribution des espèces. Nous avons combinée des modèles statiques (Maxent et régression logistique) avec des données du modèle climatique global CNRM CM5, et sur la base de l'occurrence de ces taxons entre 1950 et 2000. Il en ressort que les espèces du genre Guibourtia sont sensibles aux facteurs précipitation (69,2 %) et amplitude thermique (74,3 %). Dans un second temps, il sera utilisé les modèles climatiques des ères géologiques passées afin d'inférer la distribution de l'espèce au cours du Quaternaire, et de faire le lien avec des analyses phylogénétiques et phylogéographiques. Il sera également possible d'évaluer la distribution future de l'espèce tenant compte des modèles d'évolution du climat. Enfin, le projet de recherche s'attèlera particulièrement aux relations phylogénétiques entre espèces morphologiquement similaires en sympatrie ou parapatrie, en caractérisant en détail les flux de gènes entre individus de ces taxons proches, ainsi que leur degré de similarité physiologique. Les résultats de l’étude in fine contribueront à proposer des stratégies de conservation et de gestion durable dans le contexte de l’exploitation forestière d’Afrique centrale et du changement climatique en cours. [less ▲]

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See detailICOS IN BELGIUM: WALLONIA
De Ligne, Anne ULg

Poster (2014, September 23)

Présentation ICOS Wallonia

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See detailIRGA GAS SAMPLING SYSTEM DIMENSIONING: LABORATORY AND FIELD EXPERIMENTS
De Ligne, Anne ULg; Joly, Lilian; Cousin, Julien et al

Poster (2014, September 23)

The gas sampling system (GSS), which carries air from the sampling point to the IRGA, is an essential component of the eddy covariance system. It has to meet several constraints, among which minimizing ... [more ▼]

The gas sampling system (GSS), which carries air from the sampling point to the IRGA, is an essential component of the eddy covariance system. It has to meet several constraints, among which minimizing high frequency attenuation of concentration measurement and keeping pressure drop in the measurement cell in an acceptable range. Rain cup, filters, tubes and pumps are key elements of this system and need proper dimensioning. The elaboration of the ICOS protocol for IRGA required such dimensioning and optimization. Laboratory and field measurements were carried out with this aim. In the laboratory, a dynamic calibration bench was developed to investigate experimentally the pressure drop and the concentration fluctuation attenuation caused by different filters. In the field, three LI-7200 equipped with different GSS were installed and run at the Dorinne Terrestrial Observatory (ICOS-Belgium). Main experiment conclusions were that: • The shape and size of the rain cup has a critical impact on cut off frequencies • The filter porosity and size has a critical impact on pressure drop • Filter heating is necessary in order to avoid condensation and filter blocking These experiments led to the definition of the GSS functioning range that is finally proposed in the ICOS IRGA protocol. [less ▲]

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See detailSeasonal and inter-annual variability of photosynthetic capacity in a temperate forest
Hurdebise, Quentin ULg; Vincke, Caroline; Soubie, Rémy et al

Poster (2014, September 23)

In temperate forests, the relation between vegetation phenology and carbon sequestration variability remains to be explored. To study phenology impact on CO2 fluxes, two photosynthetic capacity indicators ... [more ▼]

In temperate forests, the relation between vegetation phenology and carbon sequestration variability remains to be explored. To study phenology impact on CO2 fluxes, two photosynthetic capacity indicators were used : NEE at light saturation (NEEsat) and green proportion in canopy pictures (gcc). Correlations between these indicators were investigated at seasonal and inter-annual scale. [less ▲]

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See detailAre agricultural ecosystems important BVOC « exchangers »? Evidences from 2 measurement years on croplands at Lonzée Terrestrial Observatory (Belgium)
Bachy, Aurélie ULg; Aubinet, Marc ULg; Schoon, Niels et al

Poster (2014, September 23)

For the last decades, agricultural ecosystems have been a key biome for diverse socio-economical, environmental and climatic issues. And one of these climatic issues is just BVOC (Biogenic Volatile ... [more ▼]

For the last decades, agricultural ecosystems have been a key biome for diverse socio-economical, environmental and climatic issues. And one of these climatic issues is just BVOC (Biogenic Volatile Organic Compounds) emission from terrestrial ecosystems. Indeed, those compounds which are mostly emitted by plants play a great role in the atmospheric chemistry, thereby influencing the Earth surface radiative budget and the tropospheric air quality. However, so far, very few is known about BVOC exchange by crops, implying that huge uncertainties remain about qualifying, quantifying and determining sources/sinks and driving mechanisms of BVOC exchanges between croplands ecosystems and the atmosphere. We present here the first long term BVOC fluxes measurement study conducted on maize (2012) and winter wheat (2013), respectively the second and first most important worldwide crops (FAOSTAT). BVOC exchange was measured using the disjunct by mass scanning eddy covariance technique (+ PTR-MS, Ionicon) at the Lonzée Terrestrial Observatory (ICOS site) in Belgium. Main results are: (i) crops emit mainly methanol; (ii) BVOC emission from studied crops is lower than in literature, suggesting that agricultural ecosystems are poor BVOC exchangers; (iii) soil is a significant BVOC source. [less ▲]

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See detailA heat and dye tracer test for characterizing and modelling heat transfer in an alluvial aquifer
Klepikova, Maria ULg; Wildemeersch, Samuel; Jamin, Pierre ULg et al

Poster (2014, September 22)

Using heat as an active tracer is a topic of increasing interest with regards to characterizing shallow aquifers for ATES (Aquifer Thermal Energy Storage) systems. In this study, we investigate the ... [more ▼]

Using heat as an active tracer is a topic of increasing interest with regards to characterizing shallow aquifers for ATES (Aquifer Thermal Energy Storage) systems. In this study, we investigate the potential interest of coupling simultaneous heat and dye tracer injection tests for characterization of an alluvial aquifer. The study site is located near Liege in the alluvial aquifer of the Meuse River, Belgium. The tracing experiment consisted in simultaneously injecting heated water and a dye tracer in a piezometer and monitoring the evolution of groundwater temperature and tracer concentration in the recovery well and in nine monitoring wells located according to three transects with regards to the main groundwater flow direction. The breakthrough curves measured in the recovery well showed that heat transfer in the alluvial aquifer is slower and more dispersive than solute transport. Recovery is very low for heat while in the same time it is measured as relatively high for the solute tracer. This shows how heat diffusion is larger than molecular diffusion, implying that exchange between groundwater and the porous medium matrix is far more significant for heat than for solute tracers. In a first step, temperature and concentrations in the recovery well are used for estimating the specific heat capacity with an energy balance calculation and the estimated value is found to be consistent with those found in the literature. Then, the measured temperature breakthrough curves in the piezometers are used for constraining the heat transport model. They are highly contrasted with what would be expected in an ideal layered aquifer. They reveal strongly unequal lateral and vertical components of the transport mechanisms. A preliminary interpretation of these temperature breakthrough curves is provided with first results from the model. Then it will allow for estimating the entire set of heat transfer parameters and their spatial distribution by inverse modelling. The developed concepts and tests may lead to real projects of various extents that can be now optimized by the use of a rigorous and efficient methodology at the field scale. [less ▲]

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