References of "Poster"
     in
Bookmark and Share    
See detailConstraints on the Parental Melts of Enriched Shergottites from Image Analysis and High Pressure Experiments
Collinet, Max ULg; Medard, Etienne; Devouard, Bertrand et al

Poster (2012, March 20)

Martian basalts can be classified in at least two geochemically different families: enriched and depleted shergottites. Enriched shergottites are characterized by higher incompatible element ... [more ▼]

Martian basalts can be classified in at least two geochemically different families: enriched and depleted shergottites. Enriched shergottites are characterized by higher incompatible element concentrations and initial 87Sr/86Sr and lower initial 143Nd/144Nd and 176Hf/177Hf than depleted shergottites. It is now generally admitted that shergottites result from the melting of at least two distinct mantle reservoirs. Some of the olivine-phyric shergottites (either depleted or enriched), the most magnesian Martian basalts, could represent primitive melts, which are of considerable interest to constrain mantle sources. Two depleted olivine-phyric shergottites, Yamato 980459 and Nothwest Africa (NWA) 5789, are in equilibrium with their most magnesian olivine and their bulk rock compositions are inferred to represent primitive melts. Larkman Nunatak 06319 and NWA 1068, the most magnesian enriched basalts, have bulk Mg# that are too high to be in equilibrium with their olivine megacryst cores. Parental melt compositions have been estimated by subtracting the most magnesian olivine from the bulk rock composition, assuming that olivine megacrysts have partially accumulated. However, because this technique does not account for the actual petrography of these meteorites, we used image analysis to study these rocks history, reconstruct their parent magma and understand the nature of oli-vine megacrysts. Our image analysis results are supported by a series of high-pressure experiments performed on LAR 06319 bulk rock composition to test if it could represent a primitive melt, and understand its crystallization history. [less ▲]

Detailed reference viewed: 59 (10 ULg)
Full Text
Peer Reviewed
See detailDoes Tight Glycemic Control positively impact on patient mortality?
Penning, Sophie ULg; Le Compte, Aaron J.; Signal, Matthew et al

Poster (2012, March 20)

Detailed reference viewed: 20 (5 ULg)
Full Text
See detailInteractions of apamin with pore mutated SK3 channels
Dilly, Sébastien ULg; Lamy, Cédric; Poncin, Sylvie et al

Poster (2012, March 16)

In the present work, we have tested the impact of the replacement of valine residues in the pore region of SK3 (520) by either an alanine or a phenylalanine residue in terms of the interactions of apamin ... [more ▼]

In the present work, we have tested the impact of the replacement of valine residues in the pore region of SK3 (520) by either an alanine or a phenylalanine residue in terms of the interactions of apamin with these mutants in comparison with the corresponding native channels. Replacing valine residue at position 520 of the SK3 channel by a phenylalanine significantly increased the sensitivity of the channel to be blocked by tetraethylammonium (TEA) as previously reported. Indeed, an aromatic residue, such as a phenylalanine or a tyrosine, is frequently found in the pore region of several potassium channels more sensitive to TEA than SK channels. We measured the affinity (Kd) of apamin in saturation experiments and studied SK currents in transfected cells using patch clamp techniques. In parallel, molecular modelling techniques were used to examine the impact of these local modifications on the interaction of apamin with the corresponding channels. The presence of a phenylalanine in the pore region of potassium channels led to a higher sensitivity for TEA by creating more hydrophobic interactions as found by the docking procedure. In the in vitro binding experiments, the phenylalanine mutant (SK3VF) displayed a very low affinity for apamin. In patch clamp experiments, the SK current was only very partially blocked by apamin in the SK3VF mutant. Furthermore, apamin displayed an affinity and a blocking activity for the alanine mutant close to that for the corresponding native channels. In conclusion, the presence of a bulky and hydrophobic residue at a position near the pore mouth of SK3 channels has a negative impact on their interactions with apamin. [less ▲]

Detailed reference viewed: 79 (4 ULg)
Peer Reviewed
See detailApplication of mixed polygenic model to control for cryptic/genuine relatedness and population stratification.
Gusareva, Elena ULg; Mahachie John, Jestinah ULg; Isaacs, Aaron et al

Poster (2012, March 12)

In genome-wide association studies (GWAs), population stratification may cause inflated type I errors and overly-optimistic test results, when not properly corrected for. During the past decade, several ... [more ▼]

In genome-wide association studies (GWAs), population stratification may cause inflated type I errors and overly-optimistic test results, when not properly corrected for. During the past decade, several methods have been proposed for association testing in the presence of population stratification. Among these, principal components-based approaches are the most popular. Principal component analysis (PCA) allows data transformation to a new coordinate system such that the projection of the data along the first new coordinate (called the PC1) has the largest variance; the second PC has the second largest variance, and so on. In practice, two components are usually enough to adjust or to control for population stratification. They can easily be included in parametric association models as covariates. Despite the success of this strategy, there are still some caveats which need further attention. Among these are that principal component-based methods generally do not account for cryptic relatedness (kinship) between supposedly unrelated individuals, are not straightforwardly adapted to accommodate family-based designs or mixtures of families and unrelated individuals, and do not always take proper account of the trait under investigation. In this work, we present an easy-to-use alternative that addresses the aforementioned issues. For quantitative traits, we propose to first use the mixed polygenic model (possibly taking into account important non-genetic confounders as covariates), second to derive “polygenic” residuals from this model – hereby removing genomic kinship relationships, and third to consider these residuals as new traits in a classical genome-wide QTL analysis for “unrelated individuals”. The polygenic component of the aforementioned mixed polygenic model describes the contribution from multiple independently segregating genes, all having a small additive effect on the trait under investigation. Via an extensive simulation study, with various settings of population stratification and admixture, we show that this approach not only removes most of the “relatedness” between individuals (cryptic relatedness or known relatedness), but also removes most of the remaining substructures caused by population stratification or admixture. As a proof of concept, we demonstrate the efficiency of this robust method to control for population stratification on real-life genome-scale data from the SNP Health Association Resource (SHARe) Asthma Resource project (SHARP) (dbGaP accession number phs000166.v2.p1). We also provide leads to extend this method to dichotomous traits. [less ▲]

Detailed reference viewed: 85 (18 ULg)
See detailL'entomophagie basée sur la production locale d'insectes comestibles : sommes-nous prêts ?
Sablon, Ludovic ULg; Alabi, Taofic Abdel Fabrice ULg; Drugmand, Didier et al

Poster (2012, March 07)

Les perspectives d’évolution de la population mondiale annoncent un accroissement continu menant à un niveau supérieur à 9 milliards d’individus d’ici 2050. Cette augmentation correspondra inévitablement ... [more ▼]

Les perspectives d’évolution de la population mondiale annoncent un accroissement continu menant à un niveau supérieur à 9 milliards d’individus d’ici 2050. Cette augmentation correspondra inévitablement à des besoins alimentaires accrus au niveau mondial. Même si des spécificités en terme de produits consommés et de disponibilités – facilités de productions varient d’une région à une autre, la limitation des superficies à consacrer aux productions agricoles, notamment dans le cadre des ressources animales est une constante. Il ne sera pas possible d’assurer des productions animales conventionnelles pour fournir les ressources nécessaires aux populations humaines à venir. Bien que les produits animaux comme sources de nutriments doivent être développés, il s’agit maintenant de se tourner vers des filières alternatives pour maximiser les ressources végétales utilisées en élevage, tout en minimisant l’espace nécessaire et les effets sur l’environnement, notamment en terme de résidus et polluants potentiels. L'entomophagie, ou le fait de consommer des insectes comme source alimentaire d’origine animale, est connue et pratiquée dans de nombreuses régions du monde depuis des siècles. A chaque situation locale, une solution entomologique comme ressource alimentaire peut être appliquée : par la collecte dans la nature ou par le développement d’élevage d’espèces indigènes. Si l’entomophagie est peu appliquée en Europe, c’est sans doute d’une part lié à une absence dans nos mœurs alimentaires et d’autre part lié à la diversité et l’abondance d’autres ressources animales plus conventionnelles dans notre référentiel occidental. Au vu de l’état prévisionnel de la difficulté à produire les ressources alimentaires animales dans un futur proche, peut-être est-il temps de ne plus considérer les insectes comme uniquement nuisibles et négatifs mais plutôt comme de nouvelles espèces à développer par exemple dans des productions industrielles. Si la taille de ces animaux d’élevage reste réduite, leurs capacités de reproduction, leurs courtes durées de développement et les taux de conversion de la biomasse végétale utilisée comme aliments nous permettent d’envisager des unités de production de tonnes de biomasses animales. En plus de cet aspect quantitatif, plusieurs paramètres qualitatifs font de nombreux insectes des ressources utiles notamment en terme de protéines (et plus particulièrement en terme de composition en acides aminés plus rares) et de lipides (avec une majorité d’acides gras insaturés, des ratios omégas 3 et 6 intéressants, l’absence de cholestérol,…). Chez nous l'entomophagie est encore méconnue même si l'on peut constater un intérêt croissant notamment ces derniers mois. Entre curiosité gustative, éveil environnementaliste lié au faibles quantités de résidus liées à la production d’insectes vis-à-vis d’autres élevages, ou efficacité de transformation de ressources végétales limitées, de plus en plus de personnes souhaitent franchir le pas de ne plus regarder mais bien goûter de l’insecte. Dans le cadre de plusieurs études menées à Gembloux Agro-Bio Tech – Université de Liège ainsi qu’à l’Insectarium Jean Leclercq – Hexapoda à Waremme, certains aspects socio-culturels liés à une diversité de préparations à base d’insectes ont été investigués. Des tendances nettes sur les critères menant à l’acceptation ou le refus catégorique de manger de l’insectes ont ainsi été déterminés. Aussi, des formulations particulières peuvent également être ciblées pour favoriser l’appréciation de la dégustation d’insectes. Face au défi alimentaire du futur et à l'intérêt croissant pour l'entomophagie dans diverses régions dont l’Europe, l’élevage industriel d’insectes constitue une piste sérieuse pour fournir une part non négligeable de produits animaux afin d’assurer des ressources notamment de divers nutriments pour les populations humaines. Diverses recherches sont actuellement en cours tant sur les aspects techniques de production que sur les approches socio-culturelles. Nul doute que d’ici quelques années, entiers ou fractionnés les insectes feront partie de nos régimes et habitudes alimentaires. [less ▲]

Detailed reference viewed: 958 (102 ULg)
Full Text
Peer Reviewed
See detailHarmonized Growth Models and Simulations of the Evolution of Pure Stands of Norway spruce, Larches and Douglas-fir for Southern Belgium (Wallonia).
Perin, Jérôme ULg; Ligot, Gauthier ULg; Cerisier, François ULg et al

Poster (2012, March 02)

In order to compare different silvicultural scenarios we have undertaken the development of a software that can simulate stand evolution in regards to their species composition, site characteristics and ... [more ▼]

In order to compare different silvicultural scenarios we have undertaken the development of a software that can simulate stand evolution in regards to their species composition, site characteristics and silvicultural operations. As a first approach we limited the scope of our work to even-aged and pure coniferous stands of the three most important coniferous species in Wallonia (southern part of Belgium): Norway spruce (Picea abies), douglas-fir (Pseudotsuga menziensii) and larches (Larix sp.). This presentation introduces carried out simulations and compare their outcomes. First we gathered data sets from the permanent regional inventory, from observation networks and experimental plots throughout Wallonia. Then we adjusted, for these species, harmonized and distance-independent models of dominant-height growth, tree diameter growth, mortality, and the distribution of tree diameter frequency before the first thinning. Next we implemented those models in the Capsis platform, and we simulated, for the three species, the evolution of virtual stands using different scenarios. On one hand the evolution was performed without thinning, and on the other hand we applied silvicultural scenarios that are commonly used in Wallonia. As a result these models highlight, for example, the great juvenile growth and sensibility to stands density of larches whereas Norway spruce behaves the opposite. Further work is however needed to predict and simulate wood quality and value. Once this will be achieved we will attempt to optimize silvicultural scenarios for the three species. [less ▲]

Detailed reference viewed: 80 (25 ULg)
Full Text
See detailHow pristine is the Congo Basin forest ? Some answers from Erythrophleum spp. (Caesalpiniaceae) and Pericopsis elata (Fabaceae) natural stands in southeastern Cameroon
Bourland, Nils ULg; Livingstone Smith, Alexandre; Guion, Hélène ULg et al

Poster (2012, March 01)

Erythrophleum spp. and Pericopsis elata are two important African timber taxa suffering from regeneration problems. Those light demanding trees could have established in openings made by past human ... [more ▼]

Erythrophleum spp. and Pericopsis elata are two important African timber taxa suffering from regeneration problems. Those light demanding trees could have established in openings made by past human activities (mainly slash-and-burn cultivation). Our study aimed at verifying this assumption in a 340,000 ha forest concession in southeastern Cameroon. Anthracological excavations were made alongside transects opened in patches where those taxa occur as well as the surrounding environment. Numerous charcoal elements and some pottery fragments were found in excavated soils in all studied sites. Charcoals and pieces of pottery were found within the first 100 and 50 cm of soil, respectively. According to radiocarbon dating conducted on charcoals and burnt seeds, fires occurred between 2,150 to 195 years BP. This finding was consistent with the analysis of archaeological materials decoration techniques. Our results revealed intense past anthropological activities in this area, seriously questioning the assumption of a pristine Congo Basin [less ▲]

Detailed reference viewed: 66 (18 ULg)
Full Text
See detailRecent disturbances in the Congo Basin : an anthracological contribution to vegetation reconstructions
Morin-Rivat, Julie ULg; Hubau, Wannes; Gillet, Jean-François ULg et al

Poster (2012, March 01)

In contrast to the well-known vegetation history of the northern hemisphere, few is known about past vegetation change in Central Africa. However, recent palaeoecological and biogeographical studies ... [more ▼]

In contrast to the well-known vegetation history of the northern hemisphere, few is known about past vegetation change in Central Africa. However, recent palaeoecological and biogeographical studies suggest that early human disturbances had a substantial influence on Central Africa vegetation patterns, particularly allowing the expansion of light-demanding species. This interesting hypothesis is the basis of one of the main research questions of the ERA-net BIODIVERSA CoForChange project: what was and is the relationship between (increasing) human activity and vegetation change? A recently developed protocol for the identification of ancient Central African charcoal fragments opened the door for vegetation reconstructions with a high spatial and taxonomical resolution. Therefore, we chose to study macro-charcoals from pedoanthracological profiles situated in N Congo and SE Camero0n. In total, 48 taxa were found in nine radiocarbon dated profiles. At the moment, three taxa have been identified down to species level. First, we found numerous fragments of Gilbertiodendron dewevrei under a current monodominant forest of G. dewevrei (40 cm depth, 1421-1327 cal. BP). This seems to confirm the presumption that monodominant forests of G. dewevrei, shade-bearer species, are relatively stable. Second, we evidenced the lack of Triplochiton scleroxylon charcoals under a T. scleroxylon stand, which could confirm the hypothesis of the recent nature of those stands. Finally, our results suggest that taxonomic diversity of charcoal findings in open canopy Marantaceae forests is greater than in dense forests. Pterocarpus soyauxii and Millettia drastica have been found under an open Marantaceae forest at 40 cm depth (1184-1055 cal. BP). The abundance of the light-demanding species P. soyauxii appears to be decreasing over time (levels 20 to 40 cm depth) to the benefit of giant herbs. Anthracology in Central Africa is on the rise and the first results of the CoForChange project are promising. More identifications will follow, resulting in a better understanding of the evolution of Central African forests. [less ▲]

Detailed reference viewed: 206 (37 ULg)
Full Text
See detailSTEAM EXPLOSION : PROCESS AND IMPACT ON LIGNOCELLULOSIC MATERIAL
Jacquet, Nicolas ULg; Vanderghem, Caroline ULg; Danthine, Sabine ULg et al

Poster (2012, March 01)

Steam explosion is a thermomechanochemical process which allows the breakdown of lignocellulosic structural components by steam heating, hydrolysis of glycosidic bonds by organic acid formed during the ... [more ▼]

Steam explosion is a thermomechanochemical process which allows the breakdown of lignocellulosic structural components by steam heating, hydrolysis of glycosidic bonds by organic acid formed during the process and shearing forces due to the expansion of the moisture. The process is composed of two distinct stages: vapocracking and explosive decompression. Cumul effects of both phases include modification of the physical properties of the material (specific surface area, water retention capacities, color, cellulose crystallinity rate,…), hydrolysis of hemicellulosic components (mono and oligosaccharides released) and modification of the chemical structure of lignin. These effects permit the opening of lignocellulosic structures and increase the enzymatic hydrolysis rate of cellulose components in the aim to obtain fermentable sugars used in second generation biofuels process. [less ▲]

Detailed reference viewed: 95 (14 ULg)
Full Text
See detailINFLUENCE OF STEAM EXPLOSION ON CRYSTALLINITY PROPERTIES OF PURE CELLULOSE FIBER
Jacquet, Nicolas ULg; Vanderghem, Caroline ULg; Danthine, Sabine ULg et al

Poster (2012, March 01)

The aim of the present study is to compare the effect of different steam explosion treatments on crystallinity properties of a pure bleached cellulose. Steam explosion process is composed of two distinct ... [more ▼]

The aim of the present study is to compare the effect of different steam explosion treatments on crystallinity properties of a pure bleached cellulose. Steam explosion process is composed of two distinct stages: vapocracking and explosive decompression. The treatment intensities is determined by a severity factor, established by a correlation between temperature process and retention time. The results show that steam explosion treatment has an impact on the crystallinity properties of pure cellulose fiber. When the severity factor is below 5.2, an increase of the overall crystallinity of the samples is observed with the treatment intensities. For higher intensities, a significant thermal degradation of cellulose lead to an important change in substrate composition, which lead to a further decrease of cellulose crystallinity [less ▲]

Detailed reference viewed: 66 (15 ULg)
Full Text
See detailCould current Pericopsis elata (Fabaceae) patches in southeastern Cameroon be reasonably linked to past anthropogenic activities ?
Bourland, Nils ULg; Cerisier, François ULg; Livingstone Smith, Alexandre et al

Poster (2012, March 01)

Pericopsis elata is one of the most valuable African timber species. This IUCN Red Listed tree suffers from a lack of regeneration, thus its current presence provokes questioning. Our work aimed at ... [more ▼]

Pericopsis elata is one of the most valuable African timber species. This IUCN Red Listed tree suffers from a lack of regeneration, thus its current presence provokes questioning. Our work aimed at understanding its origins so as to help securing its future. This study, lead away from engineering works, was conducted in four different sites located within the natural distribution area of the species and took into account the different growing conditions were the species occurs. Our observations were based on an analysis of charcoal elements and pottery fragments discovered in subsurface layers of soils as well as on current botanical and pedological surveys. Discovered evidence of past human activities led to the assumption that this part of the Congo Basin was much more inhabited than previously thought. Some of the results obtained for P. elata could apply for other long lived light demanding species growing in the same environment. [less ▲]

Detailed reference viewed: 86 (15 ULg)
Full Text
Peer Reviewed
See detailSMALL SAMPLE SIZE CAPABILITY INDEX FOR ASSESSING VALIDITY OF ANALYTICAL METHODS
Rozet, Eric ULg; Boulanger, B.; Ziemons, Eric ULg et al

Poster (2012, March)

Analytical method’s capability evaluation can be a useful methodology to assess the fitness of purpose of these methods for their future routine application. However, care on how to compute the capability ... [more ▼]

Analytical method’s capability evaluation can be a useful methodology to assess the fitness of purpose of these methods for their future routine application. However, care on how to compute the capability indices has to be made. Indeed, the commonly used formulas to compute capability indices such as Cpk, will highly overestimate the true capability of the methods. Especially during methods validation or transfer, there are only few experiments performed and, using in these situations the commonly applied capability indices to declare a method as valid or as transferable to a receiving laboratory will conduct to inadequate decisions. In this work, an improved capability index, namely Cpk-tol and the corresponding estimator of proportion of non conforming results (tolCpk−π) is proposed. Through Monte-Carlo simulations, they have been shown to greatly increase the estimation of analytical methods capability in particular in low sample size situations as encountered during methods validation or transfer. Additionally, the usefulness of this capability index is illustrated through several case studies. [less ▲]

Detailed reference viewed: 113 (10 ULg)
See detailSituation épidémiologique du virus de l’hépatite E chez le sanglier (Sus scrofa) en Belgique
Thiry, Damien ULg; Mauroy, Axel ULg; Brochier, Bernard et al

Poster (2012, March)

Detailed reference viewed: 5 (2 ULg)
Full Text
Peer Reviewed
See detailAN INNOVATIVE APPROACH TO SELECT THE PREDICTION MODEL IN THE DEVELOPMENT OF NIR SPECTROSCOPIC METHODS
Ziemons, Eric ULg; Mantanus, Jérôme ULg; Rozet, Eric ULg et al

Poster (2012, March)

Taking into account its non-invasive, non-destructive character and fast data acquisition, near infrared spectroscopy is more and more integrated in production processes to acquire analytical results ... [more ▼]

Taking into account its non-invasive, non-destructive character and fast data acquisition, near infrared spectroscopy is more and more integrated in production processes to acquire analytical results. Implementation of a NIR quantitative method is performed using an iterative heuristic approach that will ultimately build a model allowing the prediction of the concentration of the analyte of interest. In this context, the aim of the present study was to develop an innovative approach based on statistical tolerance intervals and the desirability index FMI (Fitting Model Index) to select the most appropriate prediction model from a list of candidate models instead of using conventional criteria such as R², RMSEC, RMSECV and RMSEP [1-2] without objective decision rules. This new approach is illustrated on different steps of a real pharmaceutical manufacturing process: water and Active Pharmaceutical Ingredient (API) determinations in pharmaceutical pellets. Variability sources such as production campaigns, batches, days and operators were introduced in the calibration and validation sets. Partial Least Square (PLS) regression on the calibration sets was performed to build prediction models of which the ability to quantify accurately was tested with the validation sets. Regarding the product specifications, the acceptance limits were set at 20% and 5%, for the moisture and API determination, respectively.As can be seen from Figure 1 and 2, this innovative approach based on the desirability index FMI of the accuracy profile enabled to build and select the most appropriate prediction model in full accordance with its very final goal, to quantify as accurately as possible the analytes of interest. [1] Hubert Ph. et al., J. Pharm. Biomed. Anal., 36, 2007, 579-586. [2] Rozet E. et al., Ana. Chim. Acta, 591, 2007, 239-247. [less ▲]

Detailed reference viewed: 79 (15 ULg)
Full Text
Peer Reviewed
See detailDu traumatisme obstétrical à la désinsertion trachéale.
Lecomte, Laurie; DEMEZ, Pierre ULg; François, Anne et al

Poster (2012, March)

Les désinsertions trachéales traumatiques néonatales sont exceptionnelles. Elles sont généralement associées à une intubation compliquée, mais quelques descriptions ont été faites de ruptures trachéales ... [more ▼]

Les désinsertions trachéales traumatiques néonatales sont exceptionnelles. Elles sont généralement associées à une intubation compliquée, mais quelques descriptions ont été faites de ruptures trachéales partielles dans le décours d’un traumatisme obstétrical. Quelle que soit l’étiologie de la lésion trachéale, la prise en charge peut être conservatrice (par cicatrisation « simple » autour d’un tube entotrachéal) ou chirurgicale (par réparation des lésions). [less ▲]

Detailed reference viewed: 16 (0 ULg)
Full Text
Peer Reviewed
See detailPilot Trial of STAR in Medical ICU
Fisk, Liam M.; Le Compte, Aaron J.; Shaw, Geoffrey M. et al

Poster (2012, March)

Detailed reference viewed: 5 (2 ULg)
Full Text
Peer Reviewed
See detailDelayed puberty in a girl due to an inactivating mutation of the LH receptor
FUDVOYE, Julie ULg; PARENT, Anne-Simone ULg; Bourguignon, Jean-Pierre ULg

Poster (2012, March)

We report the case of a 46 XY patient with a disorder of sex differentiation (DSD) caused by an inactivating mutation of the LH receptor. Mutations of genes involved in hypothalamic-pituitary-gonadal ... [more ▼]

We report the case of a 46 XY patient with a disorder of sex differentiation (DSD) caused by an inactivating mutation of the LH receptor. Mutations of genes involved in hypothalamic-pituitary-gonadal function are rare but they provide an experience of nature for understanding the physiology and the pathophysiology of gonadotropins actions. There arise from correlation between the phenotypes and genotypes in those unique conditions. Management of this particular patient with no LH activity involves oestrogen replacement therapy to induce breast development together with a gonadectomy due to the risk of gonadoblastoma in streak gonads. [less ▲]

Detailed reference viewed: 16 (1 ULg)
See detailOptimalisation d’une RT-PCR en temps réel pour la détection du virus de l’hépatite A
Zonta, William ULg; Denayer, Sarah; Thiry, Etienne ULg et al

Poster (2012, March)

En Belgique, l’incidence de l’hépatite A (HAV) est de 1,2 cas pour 100000 habitants. La population présente une faible immunité contre le HAV puisque seulement 50 % de la population possèdent des ... [more ▼]

En Belgique, l’incidence de l’hépatite A (HAV) est de 1,2 cas pour 100000 habitants. La population présente une faible immunité contre le HAV puisque seulement 50 % de la population possèdent des anticorps anti-HAV après l’âge de 30 ans. Ainsi un grand nombre d’individus reste susceptible de contracter une infection par le HAV. Les sources de contamination sont principalement le contact de personne à personne mais aussi la consommation d’aliments (crus ou « ready-to-eat) contaminés. Cette contamination peut provenir de l’eau d’irrigation pour les fruits et légumes, de l’eau de mer pour les mollusques bivalves ou de la manipulation de l’homme lors des différentes étapes entre la récolte et la vente du produit. Dans ce projet, une nouvelle RT-PCR spécifique pour la détection du HAV est développée et évaluée. Pour choisir de nouvelles amorces et sondes, des alignements sont réalisés avec les séquences de 19 souches de HAV (DNASTAR Lasergene) afin de cibler les régions les plus conservées du génome du HAV. Cinq nouveaux couples d’amorces ciblant plusieurs régions hautement conservées du génome de HAV ont été sélectionnés et testés à différentes températures d’hybridation et différentes concentrations en utilisant un agent se liant à l’ADN double brin (SYBR Green). Une sonde fluorescente, de type FAM, spécifique de l’amplicon délimité par le couple d’amorces fournissant les meilleurs résultats a été dessinée et utilisée avec la technologie d’hydrolyse de sonde à deux concentrations différentes. Des dilutions d’un facteur 10 de la suspension de la souche HM175 (HAV) ont été testées par le couple d’amorces et la sonde choisit pour établir ainsi une limite de détection. La spécificité du couple d’amorce choisit a été testé en présence de différents picornavirus et virus entériques et de 3 génotypes de HAV (IA, IB et IIIA). Le plasmide Sybricon019 et ses amorces spécifiques ont été utilisés comme contrôle interne d’amplification (IAC). Un contrôle positif a aussi été créé afin de s’assurer du fonctionnement correct de la PCR en temps réel. Parmi les 5 couples d’amorces sélectionnés, le couple HAV-F2/HAV-R2 permet d’obtenir les valeurs de Ct les plus faibles avec une concentration optimale de 300nM pour les amorces sens et anti-sens. Ce couple d’amorces cible la région VP1/VP3 du génome du HAV. Différentes températures d’hybridation ont été testées et la température la plus élevée (60°C) a été sélectionnée pour limiter le risque d’amplification aspécifique. Pour augmenter la spécificité, une sonde, HAV P2, spécifique de l’amplicon délimité par les amorces HAV-F2 et HAV-R2, est utilisée à la concentration de 250nM. Des dilutions d’un facteur 10 d’une suspension de HAV, 107 à 101 particules infectieuses par ml (déterminées par TCID50), donnent respectivement des valeurs de Ct de 19,2 à 38,4 et les dilutions de 100 à 10-2 particules infectieuses par ml ne donnent aucune amplification. La limite de détection est donc de 10 particules infectieuses par ml. La spécificité des amorces et de la sonde pour la détection du HAV est correcte puisque les trois génotypes de HAV, IA, IB et IIIA, ont été détectés alors que les différents picornavirus et virus entériques n’ont donné aucun signal fluorescent d’amplification. L’optimalisation d’un nouveau couple d’amorce et d’une sonde (HAV-F2, -R2 et -P2) ciblant une région hautement conservée du génome permet de détecter le virus HAV par RT-PCR. La région ciblée (VP1/VP3) diffère de la plupart des méthodes de détection de HAV par PCR en temps réelle décrites à ce jour. La seconde étape consiste à réaliser une série de tests dans différentes matrices alimentaires à risque (fruits de mer, fruits et légumes crus) dans le but de détecter des échantillons naturellement contaminés par le HAV. [less ▲]

Detailed reference viewed: 111 (12 ULg)
Full Text
Peer Reviewed
See detailProtocol 3 : Belgian innovative projetcs to help community dwelling frail elderly
de Almeida Mello, J; Maggi, Patrick ULg; Van Durme, T et al

Poster (2012, March)

Detailed reference viewed: 61 (8 ULg)
Peer Reviewed
See detailFoodborne Outbreak by a Recombinant Norovirus GIIg/1 Strain in a University Hospital in Munich
Hoffmann, Dieter; Mauroy, Axel ULg; Foley, Brian et al

Poster (2012, March)

Detailed reference viewed: 56 (1 ULg)
Full Text
Peer Reviewed
See detailRisques d'introduction des alphavirus responsables des encéphalites virales équines américaines en Belgique
De la Grandière de Noronha Cotta, Maria Ana ULg; Dal Pozzo, Fabiana ULg; Francis, Frédéric ULg et al

Poster (2012, March)

Les virus transmis par des arthropodes hématophages (arbovirus) représentent une menace pour la santé animale et humaine en fonction de l’augmentation de l’émergence des arboviroses en dehors des ... [more ▼]

Les virus transmis par des arthropodes hématophages (arbovirus) représentent une menace pour la santé animale et humaine en fonction de l’augmentation de l’émergence des arboviroses en dehors des territoires endémiques. Les arbovirus étudiés ici appartiennent au genre Alphavirus et à la famille des Togaviridae, et sont composés d’un génome à ARN simple brin de polarité positive et enveloppés. Ces virus sont des pathogènes exotiques des équidés et causent des maladies graves chez l’homme lors d’épidémies. Les arbovirus présentent une épidémiologie complexe car ils se retrouvent au centre de l’interaction avec 5 composants : le virus, le vecteur, le réservoir, les espèces animales sensibles et l’environnement. Les voies d’introduction possible en Belgique de ces virus ont été investiguées ici en fonction des caractéristiques étiologiques et épidémiologiques de chaque virus. L’encéphalite équine de l’Est (EEEV) a un cycle complexe principal incluant les oiseaux et des moustiques comme Culiseta melanura. Les souches nord-américaines et sud-américaines peuvent être différenciées antigéniquement et génétiquement et ont des différences importantes dans leur cycle de transmission et au niveau de leur virulence. Le cycle naturel de l’EEEV se réalise chaque année dans des zones marécageuses et la migration d’oiseaux virémiques serait une hypothèse à sa réintroduction printanière annuelle. Certaines années, le virus peut être amplifié pendant ce cycle oiseaux-moustiques et le virus devient disponible à d’autres espèces de vecteurs qui font le pont entre les oiseaux et les humains ou d’autres mammifères comme les chevaux. Grâce à cette observation, l’EEEV a pu être isolé de vecteur comme Ochlerotatus sollicitans, Coquillettidia perturbans ou encore Culex pipiens et Aedes vexans qui sont deux espèces bien présentes en Europe. Le risque d’importation de l’EEEV semble peu élevé, elle pourrait se faire par l’intermédiaire du transport volontaire ou involontaire, légal ou illégal d’espèces réservoirs d’oiseaux comme des passériformes (ex : moineau domestique ou des oiseaux d’eau (ex : Egretta thula), des rongeurs comme le rat des cotonniers, des vertébrés ectothermiques comme les amphibiens (ex : Rana catesbeiana) ou des reptiles (ex : Agkistrodon piscivorus), ou encore par le transport accidentel de vecteurs compétents. L’encéphalite équine de l’Ouest (WEEV) est retrouvée dans l’Ouest de l’Amérique du Nord et en Amérique du Sud. Ce virus est un virus recombinant entre le Sindbis virus et l’EEEV. Le virus est inclus dans un cycle qui implique des passereaux et Culex tarsalis. Un deuxième cycle moins connu est rapporté et implique un lapin ou lièvre sauvage (Lepus europaeus) avec un moustique du genre Aedes. Comme pour l’EEEV, les humains et les chevaux ne développent pas une virémie suffisante pour infecter les moustiques et continuer le cycle. Le WEEV pourrait être introduit en Europe par différentes voies : les vecteurs arthropodes adultes infectés ou leurs œufs pour Aedes dorsalis, l’introduction d’oiseaux comme des passériformes ou des mammifères comme le lièvre sauvage virémiques. L’acquisition de la compétence d’un vecteur indigène local comme Culex pipiens ou Aedes dorsalis doit aussi être envisagée. Le groupe des virus de l’encéphalite équine vénézuélienne (VEEV) est sous-divisé en souches enzootiques et souches épizootiques qui utilisent le cheval comme hôte amplificateur. Les souches épizootiques sont opportunistes pour leur choix de vecteurs avec comme conséquence un large panel de vecteurs potentiels. L’introduction et l’établissement de ce virus en Belgique est possible via des moustiques infectés, des rongeurs comme le rat des cotonniers ou des oiseaux d’eau infectés, des chevaux et des hommes infectés qui sont des hôtes amplificateurs pour les souches épizootiques. En conclusion, il convient de faire la distinction entre l’introduction et l’établissement d’une infection de ces virus en Belgique. L’introduction peut se faire par l’intermédiaire de vecteurs insectes ou d’hôtes oiseaux ou mammifères comme les rongeurs ou encore le cheval et l’homme dans le cas du VEEV épizootique. Le maintien de l’infection nécessite la présence de vecteurs indigènes avec une compétence vectorielle ou de vecteurs compétents invasifs pour ces virus ainsi que la présence d’hôtes mammifères ou oiseaux phylogénétiquement apparentés à des espèces réservoirs dans les régions américaines où ces virus sont endémiques. [less ▲]

Detailed reference viewed: 60 (3 ULg)
Full Text
Peer Reviewed
See detailAnalysis of tobacco mainstream smoke by GC×GC TOFMS
Brokl, Michal ULg; Bishop, Louise; Wright, Christopher et al

Poster (2012, March)

Detailed reference viewed: 20 (6 ULg)
Full Text
Peer Reviewed
See detailAnthropisation des paysages: Structure spatiale, impact écologique, entropie
Vranken, Isabelle ULg; Bogaert, Jan ULg; Visser, Marjolein

Poster (2012, February 29)

Structural and thermodynamic applications of entropy related to spatial heterogeneity under growing anthropogenic pressure have been examined. 16 zones from classified LANDSAT TM scenes presenting ... [more ▼]

Structural and thermodynamic applications of entropy related to spatial heterogeneity under growing anthropogenic pressure have been examined. 16 zones from classified LANDSAT TM scenes presenting different anthropogenic effect intensities have been used. Anthropogenic effects, compositional and configurational entropy have been measured. The scatter plot shows bell curves with maximal entropy at intermediate anthropogenic effects. Distinction of natural and anthropogenic classes shows opposed tendencies according to class and compositional/configurational type. These results have been interpreted as spatial transformation processes, energy production and release, and linked to the habitat heterogeneity and intermediate disturbance hypotheses. [less ▲]

Detailed reference viewed: 140 (21 ULg)
Full Text
See detailBiofuel by-product for poultry diets
Hissette, Mathias ULg; Destain, Jacqueline ULg; Thewis, André ULg et al

Poster (2012, February 28)

Detailed reference viewed: 48 (13 ULg)
Full Text
See detailReconstruction of the long-term satellite-derived sea surface temperature in the South China Sea
Huynh, Thi Hong Ngu ULg; Alvera Azcarate, Aïda ULg; Barth, Alexander ULg et al

Poster (2012, February 24)

The AVHRR (Advanced Very High Resolution Radiometer) sea surface temperature is very useful for researches in oceanography because of its high resolution. An AVHRR limitation is the high missing data ... [more ▼]

The AVHRR (Advanced Very High Resolution Radiometer) sea surface temperature is very useful for researches in oceanography because of its high resolution. An AVHRR limitation is the high missing data percentage due to cloud coverage. In the South China Sea, the average missing data is usually more than 80%, especially more than 95% in the region near the Borneo Island. In this study, we use DINEOF tool to reconstruct a daily night-time AVHRR data set with horizontal resolution of 4km spanning from 1989 to 2009. Besides, a comparison between the results and in situ data is shown. The EOF analysis shows that the first three modes explain about 95% of seasonal variability. [less ▲]

Detailed reference viewed: 57 (7 ULg)
Full Text
See detailViewing through the clouds in satellite images
Troupin, Charles ULg; Barth, Alexander ULg; Alvera Azcarate, Aïda ULg et al

Poster (2012, February 24)

Detailed reference viewed: 20 (6 ULg)
Full Text
See detailSupervised learning to tune simulated annealing for in silico protein structure prediction
Marcos Alvarez, Alejandro ULg

Poster (2012, February 21)

Simulated annealing is a widely used stochastic optimization algorithm whose efficiency essentially depends on the proposal distribution used to generate the next search state at each step. We propose to ... [more ▼]

Simulated annealing is a widely used stochastic optimization algorithm whose efficiency essentially depends on the proposal distribution used to generate the next search state at each step. We propose to adapt this distribution to a family of parametric optimization problems by using supervised machine learning on a sample of search states derived from a set of typical runs of the algorithm over this family. We apply this idea in the context of in silico protein structure prediction. [less ▲]

Detailed reference viewed: 105 (26 ULg)
Full Text
See detailImpact of glycerol and storage temperature on gluatathione concentration and physiological state of Pseudomonas fluorescens BTP1 freeze-dried
Mputu Kanyinda, Jean-Noël ULg; Pierart, C.; Delvigne, Frank ULg et al

Poster (2012, February 15)

Pseudomonas fluorescens is commonly used as bio-fungicides in agriculture. For this use it requires formulations as either liquid or powder. Formulations have two advantages, storage and transport. Freeze ... [more ▼]

Pseudomonas fluorescens is commonly used as bio-fungicides in agriculture. For this use it requires formulations as either liquid or powder. Formulations have two advantages, storage and transport. Freeze-drying is a commonly used method to preserve bacteria. However, freeze-drying damages the cells, which results in loss of viability. Protective compounds are used to reduce loss of viability during process (freeze-drying and storage). In our study we used flow cytometry analysis to assess the physiological state in which cells are at the end of freeze-drying and Glutathione (GSH) was measured before and during storage. [less ▲]

Detailed reference viewed: 58 (3 ULg)
Full Text
See detailVariability among morning and evening milk compositions during the lactation
Arnould, Valérie ULg; Gengler, Nicolas ULg; Soyeurt, Hélène ULg

Poster (2012, February 10)

The main objective of this study was to analyze milking-to-milking variability of milk yield and milk composition (such as fat and protein percentages and somatic cell count). Additional objective was to ... [more ▼]

The main objective of this study was to analyze milking-to-milking variability of milk yield and milk composition (such as fat and protein percentages and somatic cell count). Additional objective was to extend this analyze to the milk fat composition. Milk samples (n=195.960) were collected from 29.636 cows in 491 Luxembourg farms and analyzed by MIR spectrometry. The milk contents of saturated, mono-, poly- and unsaturated fatty acids, and short, medium and long chain fatty acids were predicted from the recorded MIR spectral data. As expected, the milk composition and the milk fat composition, are affected by several factors as the milking period and the days in milk. In practice, using separately milk evening and milk morning could be interesting for cheese or butter production. [less ▲]

Detailed reference viewed: 77 (29 ULg)
Full Text
See detailToward a single definition of periurban areas? A review of terms, definitions and characteristics relating to the "urban" terminology.
Andre, Marie ULg; Mahy, Grégory ULg; Lejeune, Philippe ULg et al

Poster (2012, February 10)

Remote sensing image interpretation and classification require a clear definition of what is considered as a rural, a periurban, a suburban or an urban area. Such a definition is also essential in order ... [more ▼]

Remote sensing image interpretation and classification require a clear definition of what is considered as a rural, a periurban, a suburban or an urban area. Such a definition is also essential in order to compare results of studies in periurban zones. Different terms, definitions and characteristics relating to these four concepts have been reviewed in the literature and compared according to different criteria like their type, citation frequency, strenghts and weaknesses, in the scope of a landscape evolution analysis. [less ▲]

Detailed reference viewed: 86 (19 ULg)
Full Text
See detailOptiMIR: new tools for a more sustainable dairy sector
Goubau, Amaury ULg

Poster (2012, February 10)

The OptiMIR project aims to improve the sustainability of the dairy sector by providing milk producers with new tools enabling them to manage the cow’s fertility, feeding, health, pollutants, and milk ... [more ▼]

The OptiMIR project aims to improve the sustainability of the dairy sector by providing milk producers with new tools enabling them to manage the cow’s fertility, feeding, health, pollutants, and milk quality. Data provided by milk recording organizations and recorded in different environments will be pooled and used to identify the links between animal status and milk composition changes. The entire MIR milk spectrum will be used as indicator of the cows’ status in order to 1) reduce production costs 2) give an access to high added value market and 3) reduce the environmental impact. OptiMIR is a 5 years project involving 5 research units, 11 milk recording organizations from Belgium, France, Germany, Ireland, Luxembourg, and United Kingdom. The project is co-financed by INTERREG IVB program. [less ▲]

Detailed reference viewed: 35 (6 ULg)
Full Text
See detailA new HPLC method to quantify alliin, the major sulfur compound in garlic
DETHIER, Bérénice ULg; Laloux, Morgan ULg; Hanon, Emilien et al

Poster (2012, February 10)

Garlic is recognized for centuries for its health benefits, mostly linked to its sulfur- components. Among the products extracted from the cloves, alliin retained our attention. Alliin was synthesized ... [more ▼]

Garlic is recognized for centuries for its health benefits, mostly linked to its sulfur- components. Among the products extracted from the cloves, alliin retained our attention. Alliin was synthesized. This process leads to two stereoisomers. Their HPLC separation was the aim of this work. The method described in the literature (amino column, detection at 210 nm) showed a resolution of 1,1 between the isomers. A second method was developed: the stationary phase was porous graphitic carbon and a water-ACN gradient was used for the elution. It provided a resolution of 3,2, was shorter and underwent the validation process. The method leads to satisfying results. The separation is excellent, and the validation criteria are fulfilled. This may be valuable for future research on garlic. [less ▲]

Detailed reference viewed: 60 (11 ULg)
Full Text
See detail50 Years of contrasted residue management in an agricultural crop: impacts on the soil carbon budget and on heterotrophic respiration.
Buysse, Pauline ULg; Roisin, Christian; Aubinet, Marc ULg

Poster (2012, February 10)

This study aims to estimate the carbon (C) loss by soil heterotrophic respiration (SHR) in three contrasted residue management treatments (Residue Export, Farm Yard Manure addition and Residue Restitution ... [more ▼]

This study aims to estimate the carbon (C) loss by soil heterotrophic respiration (SHR) in three contrasted residue management treatments (Residue Export, Farm Yard Manure addition and Residue Restitution after harvest) through the establishment of soil C budgets, and to compare these estimations with field SHR measurements. The soil C budgets were calculated in each case on the basis of total soil organic C content and C input data compiled since the beginning of the experiment in Belgium, 50 years ago. SHR fluxes were measured in 2010 and 2011 to compare them with the budget-based estimates and to assess SHR sensitivity to temperature. The comparison suggested that the treatment receiving the largest C input does not necessarily sequestrate the most C or produce the largest CO2 fluxes. [less ▲]

Detailed reference viewed: 39 (5 ULg)
See detailUse of Chrysoperla carnea larvae for biological control of immature stages of Leptinotarsa decemlineata
Sablon, Ludovic ULg; Haubruge, Eric ULg; Verheggen, François ULg

Poster (2012, February 10)

In laboratory assays, we demonstrated predation of Chrysoperla carnea lacewing larvae against eggs, first and second larval instars of Colorado potato beetle (CPB). When looking at the daily consumption ... [more ▼]

In laboratory assays, we demonstrated predation of Chrysoperla carnea lacewing larvae against eggs, first and second larval instars of Colorado potato beetle (CPB). When looking at the daily consumption, we found that prey consumption by the third larval instar was 3-fold higher compared to the two first instars. Partial or total consumption of prey was also numbered. Different proportions of partial/total consumption were found and these depend on the lacewing larval stage. This study provides new perspectives for possible use of C. carnea as a biological agent to control CPB. Nevertheless, additional work has to be conducted under semi-natural and field to completely evaluate this predatory potential. [less ▲]

Detailed reference viewed: 43 (1 ULg)
Peer Reviewed
See detailAphid predators sampling in agrosystems in Belgium between 2009 and 2011
Vandereycken, Axel ULg; Durieux, Delphine ULg; Joie, Emilie ULg et al

Poster (2012, February 10)

The Multicolored Asian ladybird, Harmonia axyridis Pallas (Coleoptera: Coccinellidae), was imported in 1997 in Belgium to control aphid populations. Few years ago after its introduction, this exotic ... [more ▼]

The Multicolored Asian ladybird, Harmonia axyridis Pallas (Coleoptera: Coccinellidae), was imported in 1997 in Belgium to control aphid populations. Few years ago after its introduction, this exotic insect was well adapted to temperate climate conditions and spread out all over ecosystems in Europe causing decline of other aphidophagous species. In arboreal habitats, H. axyridis is the most dominant Coccinellids but we are still lacking information about this occurrence in agrosystems. An aphidophages sampling between 2009 and 2011 was realized in four agrosystems such as broad bean, wheat, corn and potato. Nevertheless H. axyridis populations rise (5 times) from 2009 to 2011 in 2011, H. axyridis is the third most observed aphidophages after Episyrphus balteatus (De Geer) and Coccinella septempunctata (Linné). H. axyridis is the dominating species in corn with 70.83±6.60 individuals per 100m². [less ▲]

Detailed reference viewed: 30 (6 ULg)
Full Text
See detailUsing fatty acid contents in milk to improve fertility of dairy cows?
Bastin, Catherine ULg; Berry, D.P.; Soyeurt, Hélène ULg et al

Poster (2012, February 10)

Improving dairy cow fertility by means of genetic selection has become increasingly important over the last years in order to overcome the declining cow fertility. This study investigated whether the ... [more ▼]

Improving dairy cow fertility by means of genetic selection has become increasingly important over the last years in order to overcome the declining cow fertility. This study investigated whether the fatty acids profile in milk could be used as an early predictor of genetic merit for fertility. Genetic covariances among 17 fatty acid contents in milk and the number of days from calving to conception were estimated from 29,792 first-parity Holstein cows. Results substantiated the unfavorable relationship among fertility and body fat mobilization in early lactation. Also, about 75% of the genetic variability of fertility was explained by the variability in milk fatty acids profile over the lactation indicating that these traits could be used to supplement genetic evaluations for fertility. [less ▲]

Detailed reference viewed: 45 (15 ULg)
Full Text
See detailRelationships between methane emissions of dairy cattle and farm management.
Vanrobays, Marie-Laure ULg; Vanlierde, Amélie ULg; Kandel, Purna Bhadra ULg et al

Poster (2012, February 10)

Livestock is considered as an important contributor to global methane emissions, predominately due to methanogenesis from ruminants. Moreover, these emissions also represent major losses of energy for ... [more ▼]

Livestock is considered as an important contributor to global methane emissions, predominately due to methanogenesis from ruminants. Moreover, these emissions also represent major losses of energy for dairy cows and therefore are linked to production efficiency. The on-going development of predictive equations (e.g., from milk composition) would allow to relate methane emissions to farm management (e.g., nutrition, environment) on a large scale in the Walloon Region of Belgium. Finally, by acquiring improved knowledge of these relationships, contributions to mitigate methane emissions could be based on an improved management of dairy herds. [less ▲]

Detailed reference viewed: 86 (33 ULg)
Full Text
Peer Reviewed
See detailAnthropogenic effect on landscapes: spatial structure, ecological impact, entropy
Vranken, Isabelle ULg; Bogaert, Jan ULg; Visser, Marjolein

Poster (2012, February 10)

Structural and thermodynamic applications of entropy related to spatial heterogeneity under growing anthropogenic pressure have been examined. 16 zones from classified LANDSAT TM scenes presenting ... [more ▼]

Structural and thermodynamic applications of entropy related to spatial heterogeneity under growing anthropogenic pressure have been examined. 16 zones from classified LANDSAT TM scenes presenting different anthropogenic effect intensities have been used. Anthropogenic effects, compositional and configurational entropy have been measured. The scatter plot shows bell curves with maximal entropy at intermediate anthropogenic effects. Distinction of natural and anthropogenic classes shows opposed tendencies according to class and compositional/configurational type. These results have been interpreted as spatial transformation processes, energy production and release, and linked to the habitat heterogeneity and intermediate disturbance hypotheses. [less ▲]

Detailed reference viewed: 49 (5 ULg)
Full Text
Peer Reviewed
See detailRhizobacterial volatile organic compounds modulate biomass production and root architecture in Arabidopsis thaliana (L.) Heynh.
Varin, Sébastien; Saunier de Cazenave-Mendaluk, Magdalena ULg; Ormeno-Lafuente, Elena et al

Poster (2012, February 10)

Detailed reference viewed: 23 (0 ULg)
Full Text
See detailEvaluation of the genetic diversity of honey bees, Apis mellifera L. in the Walloon Region and selection of strains tolerant to the mite Varroa destructor Anderson and Trueman
Leclercq, Gil ULg; Nguyen, Bach Kim ULg; Gengler, Nicolas ULg et al

Poster (2012, February 10)

For more than a decade, high losses of honey bee colonies have been noticed in several countries, including Belgium. Currently often the mite Varroa destructor is considered a main threat for beekeeping ... [more ▼]

For more than a decade, high losses of honey bee colonies have been noticed in several countries, including Belgium. Currently often the mite Varroa destructor is considered a main threat for beekeeping. In view of the inefficiency of the current chemical treatments, one of the solutions is to select honey bees tolerant to this parasite using genomic selection. To reach this objective the genetic diversity of honey bees needs first to be studied using mainly ‘Single Nucleotide Polymorphisms’ (SNP). Records and samples will be collected all over the Walloon Region in order to create an informative phenotypic and genomic data base that will be used for ‘Genome Wide Association Studies’ (GWAS) to detect associations between SNPs and tolerance, and to select bees tolerant to Varroa destructor. [less ▲]

Detailed reference viewed: 340 (28 ULg)
Peer Reviewed
See detailImplication of honeydew microflora in ant-aphid mutualism
Fischer, Christophe ULg; Lognay, Georges ULg; Haubruge, Eric ULg et al

Poster (2012, February 10)

Some ant and aphid species can present a mutualistic relationship, ants using aphid honeydew as sugar source and in exchange providing the aphid colony cleaning and protection. From a behavioral point of ... [more ▼]

Some ant and aphid species can present a mutualistic relationship, ants using aphid honeydew as sugar source and in exchange providing the aphid colony cleaning and protection. From a behavioral point of view, this phe-nomenon has been well studied from decades. However, its chemistry and semiochemical mechanisms are still largely unknown. This study aims to identify semiochemicals involved in the establishment of this relation, using both chemical and behavioral approaches. Bioassays revealed that the great-est part of ant attraction toward aphid colonies is due to honeydew volatile compounds; enabling ant scouts to find more quickly aphid colonies and distantly recognize myrmecophilous species. Many of those VOCs seeming to have microbial origins, the main honeydew microorganisms have been isolated and their roles in VOCs production and ant attraction have been investigated. It appeared that honeydew microflora holds a key role in the establishment of ant-aphids mutualistic relationship. [less ▲]

Detailed reference viewed: 120 (14 ULg)
Full Text
Peer Reviewed
See detailCharacterization of Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) overwintering sites
Fassotte, Bérénice ULg; Durieux, Delphine ULg; Haubruge, Eric ULg et al

Poster (2012, February 10)

The invasive multicoloured Asian ladybird, Harmonia axyridis (Pallas), forms large aggregations inside dwellings to overwinter. In order to highlight the specific features of infested houses, we ... [more ▼]

The invasive multicoloured Asian ladybird, Harmonia axyridis (Pallas), forms large aggregations inside dwellings to overwinter. In order to highlight the specific features of infested houses, we investigated a large number of overwintering sites in Wallonia between 2007 and 2011. These sites were characterized through a survey sent to homeowners confronted to invasion problems. The results indicate that H. axyridis preferentially selects isolated brick houses with red or white fronts to take shelter. Aggregations are mostly located at the first floor, essentially inside south or west oriented rooms. Furthermore, ladybirds generally gathered into wooden windows frames facing south or west, and to a lesser extent, in the upper corners of walls presenting the same orientation. [less ▲]

Detailed reference viewed: 26 (13 ULg)
Full Text
See detailReplacing explicit water and membrane molecules in molecular dynamics simulation to boost simulation speed
Steinhauer, Sven ULg; Crowet, Jean-Marc ULg; Lins, Laurence ULg et al

Poster (2012, February 10)

Molecular dynamics (MD) is an appropriate method for investigation of biomolecular systems and helps in explaining results from wet lab experiments or in getting further insight into details, which are ... [more ▼]

Molecular dynamics (MD) is an appropriate method for investigation of biomolecular systems and helps in explaining results from wet lab experiments or in getting further insight into details, which are not accessible by experimental methods(Lindahl, 2008). By now, many biologically relevant processes for drug design, toxicological studies and other fields of application, can not be performed by atomistic MD simulations (Lindahl, 2008). In MD, the necessary time effort for carrying out a simulation is considerable and depends mainly on (1) the complexity of the simulated system (2) the simulated time scale (3) the simulation method (4) the efficiency of used hardware and software algorithms. Carried out MD simulations nowadays may still take weeks of calculation on high end computers. In practice, biologically relevant processes, as e.g. protein folding, take usually place above the time scale of milli seconds. They can take up to the order of some thousands of seconds (in case of the folding of membrane proteins). Molecular dynamics computer simulations have reached the scale of micro seconds for simulations of systems where each atom was described and simulated over time.(Lindahl, 2008) Nevertheless, MD has risen to an important promoter methodology for many different fields of application. By replacing bunches of atoms by artificial particles, complexity of the systems can be reduced. This method is called the coarse grain method (CG). Biggin and Bond (2008) found an acceleration of their simulation processes for self assembling membrane / protein systems in water by factor 100. They estimated one to two days of calculation for a simulated time scale of 0.1 to 0.2 micro seconds for their systems. Implicit force fields like "IMPALA", aim to describe water and/or membrane molecules in simulations by a couple of simple and partially precalculable equations. “IMPALA” is a force field initially developed by our laboratory. Using this method, thousands of water and lipid molecules can be replaced, leading to a reduced complexity of the system to be simulated. "IMPALA"(Ducarme et al., 1998) based on the assumption of rigid peptides and aimed to find the insertion characteristics of such in membranes. Elimination of the necessity for simulating the aqueous and lipid phase atom by atom in the software package "Gromacs"(Berendsen et al., 1995) will permit both: a gain of speed, as it was already the case for the introduction of the coarse grain method, and a gain of precision by turning rigid molecules flexible through "Gromacs". Our current work is the integration of the "IMPALA" implicit force field into "Gromacs". Biggin, P.C. & Bond, P.J. Molecular dynamics simulations of membrane proteins. Methods Mol. Biol. 443, 147-60(2008). Berendsen, et al. (1995) Comp. Phys. Comm. 91: 43-56. Ducarme, P., Rahman, M. & Brasseur, R. IMPALA: a simple restraint field to simulate the biological membrane in molecular structure studies. Proteins 30, 357-71(1998). Lindahl, E.R. (2008). Molecular dynamics simulations. Methods Mol. Biol. 443, 3-23. [less ▲]

Detailed reference viewed: 85 (6 ULg)
See detailBanana Streak Virus activation by tissue culture in natural interspecific banana hybrids
NINTIJE, Pierre

Poster (2012, February 10)

Banana and plantains are important in Burundi as a staple food crop and source of income for farmers. Nevertheless, their productions are threatened by pathogens among which viruses are especially harmful ... [more ▼]

Banana and plantains are important in Burundi as a staple food crop and source of income for farmers. Nevertheless, their productions are threatened by pathogens among which viruses are especially harmful. Elimination procedures of viruses are mainly performed by banana tissue culture techniques (TC) giving good sanitation results for most bananas’ viruses. However, Banana Streak Virus (BSV) a pararetrovirus is activated by TC for banana with the B genome. Therefore, there is a risk of encouraging the emergence of BSV in Burundi by the distribution of TC products to growers. In this work, we studied the activation of BSV by tissue culture in 5 banana cultivars collected in Burundi and micropropagated in vitro. The BSV activation was demonstrated in 4 cultivars using molecular tools. [less ▲]

Detailed reference viewed: 51 (1 ULg)
Full Text
See detailModelling realized niche of metallophyte species along copper and cobalt gradients on Katanga copper hills
Boisson, Sylvain ULg; Seleck, Maxime ULg; Guillaume, Arielle et al

Poster (2012, February 10)

In South Central Africa were identified more than 650 plant species tolerant to heavy metals, several of which endemic to Katanga and critically endangered by mining activities. These metallophyte are ... [more ▼]

In South Central Africa were identified more than 650 plant species tolerant to heavy metals, several of which endemic to Katanga and critically endangered by mining activities. These metallophyte are distributed over a hundred hills containing high copper and cobalt concentrations (20 to 10000 mg/kg for copper and 2 to 1000 mg/kg for cobalt). To understand the response of metallophyte to heavy metals, the ecological niches of 80 cupro-cobaltophytes were modeled with general additive models (GAM). Results show that (1) three groups of species were identified according to their optimum along a metal concentrations gradient and (2) a positive relationship exists between niche amplitude and optimum copper concentration. [less ▲]

Detailed reference viewed: 116 (30 ULg)
Full Text
See detailIntegration of external information into genetic evaluations by a Bayesian procedure
Vandenplas, Jérémie ULg; Gengler, Nicolas ULg

Poster (2012, February 10)

One of the most important theoretical assumptions of methods used to assess genetic values is that all available information has to be considered simultaneously to obtain unbiased estimates. However, the ... [more ▼]

One of the most important theoretical assumptions of methods used to assess genetic values is that all available information has to be considered simultaneously to obtain unbiased estimates. However, the widespread international exchange of genetic material and, more recently, the important development of the genomic selection lead to the coexistence of different genetic evaluations. Therefore, the blending of the different sources of information is necessary to achieve better prediction. Integration of external information into genetic evaluations by a Bayesian procedure can partially resolve the problem under some assumptions. Results from such a method that also avoids double counting among external animals are highly similar to those from a joint evaluation. [less ▲]

Detailed reference viewed: 31 (9 ULg)
Peer Reviewed
See detailHymenoptera community of pig carcasse in an urban biotope
Frederickx, Christine ULg; Dekeirsschieter, Jessica ULg; Verheggen, François ULg et al

Poster (2012, February 10)

Most reports published in the field of forensic entomology studies are focused on Diptera pattern colonization and are neglecting Hymenoptera succession. Hymenoptera are part of the entomofaunal ... [more ▼]

Most reports published in the field of forensic entomology studies are focused on Diptera pattern colonization and are neglecting Hymenoptera succession. Hymenoptera are part of the entomofaunal colonization of a dead body as parasitoids of fly pupae. However, one should consider Hymenoptera parasitoids in a forensic entomology context to evaluate the time of death. Blowflies parasitoids may indeed be of particular importance as their time of attack is often restricted to a small, well-defined window of developmental time of the insect host. Because these parasitoids also interfere with developmental times of colonizing Diptera, a better understanding of their ecology is needed. [less ▲]

Detailed reference viewed: 43 (5 ULg)
Full Text
See detailVolatile organic compounds released by barley roots attract wireworms
Barsics, Fanny ULg; Fiers, Marie ULg; Haubruge, Eric ULg et al

Poster (2012, February 10)

Wireworms are the soil dwelling larvae of click beetles and are pests of many crops worldwide. Alternatives to insecticide treatments are needed in order to develop integrated management strategies. Our ... [more ▼]

Wireworms are the soil dwelling larvae of click beetles and are pests of many crops worldwide. Alternatives to insecticide treatments are needed in order to develop integrated management strategies. Our work consists in elucidating the role of barley root-emitted volatile organic compounds on the orientation behaviour of Agriotes sordidus wireworms. Using a dual choice olfactometer we have evaluated the attractiveness of a variety of baits ranging from barley roots themselves to isolated root-emitted volatile organic compounds. Wireworms were significantly attracted towards most of the tested baits. Our results should be taken into account in varietal selection, in crop rotation, or in trapping systems aiming at the reduction of the populations of this pest. [less ▲]

Detailed reference viewed: 65 (12 ULg)
Full Text
See detailImpact of cultivation practices on soil respiration
Dufranne, Delphine ULg; Vancutsem, Françoise ULg; Bodson, Bernard ULg et al

Poster (2012, February 10)

Cultivation practices are known to induce a modification of soil organic matter quantity, quality and spatial distribution, which may impact dry matter decomposition kinetics. In order to bring answers to ... [more ▼]

Cultivation practices are known to induce a modification of soil organic matter quantity, quality and spatial distribution, which may impact dry matter decomposition kinetics. In order to bring answers to these questions, a multidisciplinary project (SOLRESIDUS) was set up by the University of Liege, Gembloux Agro-Bio Tech in collaboration with Walloon Agricultural Research Centre (CRA-W). The aim was to investigate the impact of cultivation practices (tillage and residue restitution) on crop growth, yield and environment, as well as on soil properties and on activities. In the present study, we focused on the impacts on soil respiration soil for 3 years. We will present our first results. [less ▲]

Detailed reference viewed: 38 (10 ULg)
Full Text
See detailRelevance of pedotopographical indicators in the assessment of spatial distribution of soil water resources under forest stands. General Methodology.
Ridremont, François ULg; Claessens, Hugues ULg

Poster (2012, February 08)

Water resources constitute one of the most decisive factors of the adaptation of forest ecosystems facing climate changes. The assessment of soil water resources should lead a better understanding of ... [more ▼]

Water resources constitute one of the most decisive factors of the adaptation of forest ecosystems facing climate changes. The assessment of soil water resources should lead a better understanding of forest sites vulnerability to water stress and provide appropriate management recommendations for the choice of trees species and sylvicutlural techniques. This study aims to confront mapping pedotopographical indicators related to the water resource richness of forest sites to the soil moisture regime. The effect of soil moisture on the forest ecosystem productivity and the bioindicator expression of flora will be study too. [less ▲]

Detailed reference viewed: 34 (12 ULg)
Full Text
See detailStudy of pesticide retention on leaves using high-speed imaging
Massinon, Mathieu ULg; Lebeau, Frédéric ULg

Poster (2012, February 08)

Detailed reference viewed: 48 (17 ULg)
See detailRole of western lowland gorilla (Gorilla gorilla gorilla Savage & Wyman, 1847) on the dynamics of tropical logged forest ecosystems
Haurez, Barbara ULg; Petre, Charles-Albert ULg; Doucet, Jean-Louis ULg

Poster (2012, February 08)

The western lowland gorilla (Gorilla gorilla gorilla Savage & Wyman) (WLG) which is considered as a critically endangered species by IUCN, could play a fundamental function in seeds dispersal of several ... [more ▼]

The western lowland gorilla (Gorilla gorilla gorilla Savage & Wyman) (WLG) which is considered as a critically endangered species by IUCN, could play a fundamental function in seeds dispersal of several plant species. This could be related to its frugivorous diet, its stomach capacity and the long gut retention time of the ingested food, its extensive daily path length, and its ability to swallow seeds of variable sizes. In addition, this animal tends to deposit most of ingested seeds in suitable habitats (especially logging gaps and old logging roads) for light-demanding plant development. This research will be conducted within the moist evergreen forest of Central Gabon in a logging concession granted to the company CEB Precious Woods. A preliminary study was undertaken as a Master thesis. It was aiming at obtaining a first insight of interactions between WLG and timber exploitation in Central Gabon and at assessing the extent to which they may benefit of each other. WLG abundances were estimated in unlogged and logged sites in the concession, and nesting behavior described. Seeds dispersed during the study period (February-May) by WLG were identified through fecal analysis. Relatively high WLG abundances were observed in the concession. WLG were found to nest preferentially in open areas and to frequently use old logging road network for nesting and feeding. Sixteen species were observed to be dispersed by WLG. Seeds of the most abundant species, Santiria trimera, were subjected to four treatments: (1) passed seeds, (2) passed seeds in fecal matrix, (3) seeds surrounded by fresh pulp and (3) seeds extracted from fresh fruits. The germination successes of S. trimera were significantly higher after gut passage partly thanks to fruit pulp removal. Our PhD study aims to characterize the functional ecology of WLG in tropical forests dynamics, especially regarding logging biotopes. Our research will be organized in three parts: (1) the survey of gorilla populations in the study area coupled with the characterization of their nests and habitats, (2) the study of dispersed species and of the effect of passage through gorilla gut on seed germination, (3) the estimate of dispersal distances for the species Santiria trimera (Burseraceae) by using molecular markers. Data for the second and third parts will be collected in one site selected thanks to the results of the survey for its high gorilla density, to assess the following assumptions: (1) gorillas favor the regeneration of many plant species, including timber trees; (2) they improve the genetic diversity and limit the genetic structure by widening the genetic pool and dispersing diasporas on large distances. If these hypotheses are accepted, sylvicultural practices may be adapted so as to take advantage from the presence of gorilla population. [less ▲]

Detailed reference viewed: 108 (10 ULg)
Full Text
See detailDéfinition du profil écologique de l'azobé (Lophira alata Banks ex Gaertn F., Ochnaceae) dans les forêts sempervirentes du Cameroun
Biwole, Achille ULg; Bourland, Nils ULg; Doucet, Jean-Louis ULg

Poster (2012, February 08)

Ekki or L. alata is a commercial timber species in Guinea-Congolian region considered vulnerable (IUCN, 2011). Indeed, its population structure shows a severe lack of regeneration in some rainforests ... [more ▼]

Ekki or L. alata is a commercial timber species in Guinea-Congolian region considered vulnerable (IUCN, 2011). Indeed, its population structure shows a severe lack of regeneration in some rainforests (Palla et al., 2002). Moreover, in logging areas, insufficient knowledge about its ecological profile limits any reliable modeling of population dynamics on a long term. Consequently, original research, to improve its ecological characterization to ensure its sustainable management is conducted in moist evergreen forest in southern Cameroon. First results on population dynamics of this species show, in plots study of recruitment, a population without major deficit regeneration. On its silvicultural ability, although that estimated on plantations on parks under 2 years old, the trends of growth (ca 30 and 0.5 cm / year respectively in height and diameter) and mortality (3, 3% / year) suggest a positive perspective. Current work in relation to other topics of research should provide further insights into its ecological profile in the evergreen forests of Cameroon. [less ▲]

Detailed reference viewed: 155 (37 ULg)
Full Text
See detailTraining image scenarios for the Meuse alluvial aquifer and consistency with geophysical data
Hermans, Thomas ULg; Caers, Jef; Nguyen, Frédéric ULg

Poster (2012, February 08)

Recently, multiple-point statistics (MPS) introduced the training image (TI) concept to replace the variogram within an extended sequential simulation in order to describe more accurately multimodal ... [more ▼]

Recently, multiple-point statistics (MPS) introduced the training image (TI) concept to replace the variogram within an extended sequential simulation in order to describe more accurately multimodal distributions, with interconnected and curvilinear structures, such as those of alluvial plains. The role of the TI is to depict the conceptual geological patterns and it should be representative of the geological heterogeneity. MPS consists in extracting patterns from the training image, and anchoring them to subsurface data (e.g. well-log, seismic and production data). The construction of TI is one of the most critical and important step of MPS. Sedimentological studies may not be always available in a particular area. In this work, the alluvial aquifer of the Meuse river in the area of Liege is being investigated and there is few sedimentological data to build directly 3D conceptual model of the aquifer. In this context, we used general features of the Meuse river (slope, rate of flow, type of fluvial system) to select hydrofacies (based on a lithological classification in clay, sand and gravel) and their geometrical characteristics (channels and lobes of different sizes). Then several scenarios were built using these parameters to represent the uncertainty related to different possible geological scenarios. To verify the consistency of these TIs, a comparison with 2D electrical resistivity tomography data was carried out. 2D sections were randomly selected in the TIs and several cases were analyzed including the size of channels and lobes, the influence of surface resistivity in the results and the influence of the electrical resistivity of each facies. Forward and inverse electrical resistivity modelling was conducted on these synthetic models and the results were compared to field cases. The approach followed for the comparison is based on the calculation of a Euclidean distance between models and the visualization in a 2D or 3D space using multidimensional scaling (MDS). This technique allows verifying if field cases fall in the distribution represented by synthetic cases. In a second step, a cluster analysis was achieved on the MDS-map to provide a sensitivity analysis and to highlight which parameters were the most important for building training images. Then, the probability of each scenario was evaluated for the field cases using conditional probability. Conditional probability requires the calculation of the density function corresponding to the probability of the data given a geological scenario. This density function was obtained using a kernel density estimation technique based on the observations of the 2D MDS-map. Both the cluster analysis and the calculation of conditional probabilities for uncertain geological scenarios show that some parameters are not very sensitive (size of clay lenses, surface resistivity distribution) and that we can narrow the range of variations of some parameters (facies electrical resistivity values, gravel bodies size is more likely small, etc.). It shows that the investigation of the consistency of TI is an important step in each study including MPS. The next steps of the study are to generalize the analysis of the consistency of geological scenario with 3D geophysical data instead of 2D sections and to incorporate geophysical data as soft conditioning data for MPS simulations. [less ▲]

Detailed reference viewed: 42 (10 ULg)
Full Text
See detailContribution to the study of physicochemical and functional properties of hemicelluloses and xylooligosaccharides (XOS) extracted from rapeseed meal
Mertens, Cécile ULg; Paquot, Michel ULg; Destain, Jacqueline ULg et al

Poster (2012, February 08)

Rapeseed meal is one of the main industrial co-products from agriculture in Belgium, with more than 30 000 T produced each year. Beside its agricultural and energetic applications, new paths of ... [more ▼]

Rapeseed meal is one of the main industrial co-products from agriculture in Belgium, with more than 30 000 T produced each year. Beside its agricultural and energetic applications, new paths of valorization are being developed in order to add value to the rapeseed meal, usually by extraction of interesting molecules. In this thesis project, the aimed molecules are hemicelluloses, which are obtained via a global fractionation method that is being developed and optimized, constituting the first part of this project. Indeed, while rapeseed meals are globally already well exploited (mainly for their feed value), rapeseed hemicelluloses have not yet been studied for food application. Yet, hemicelluloses can be used as food additives (thickener, stabilizer, etc) mainly in bakery products. The literature being incomplete regarding the chemical structure of rapeseed hemicelluloses, one of the objectives of this project is to study their physicochemical properties, in regard with their technofunctional properties. Rapeseed hemicelluloses can also be used as raw material to produce an emergent type of prebiotic: xylooligosaccharides (XOS). These molecules can be introduced as well in the food supplement sector. Their production will be achieved by enzymatic hydrolysis, for a polymerization degree between two and five. Thus, the production and the physicochemical and technofunctional characterization of rapeseed XOS constitute the last objective of this project. This thesis is part of the SYNBIOFOR project, which aim is to create new symbiotic ingredients. [less ▲]

Detailed reference viewed: 237 (22 ULg)
Full Text
Peer Reviewed
See detailDesign of a biofilm reactor comprising a metal structured packing for the production of lipopeptides by B. subtilis
Zune, Quentin ULg; Ongena, Marc ULg; Toye, Dominique ULg et al

Poster (2012, February 08)

Abstract : The design of a new single species biofilm bioreactor has been investigated. Bacillus subtilis S499 has been chosen as a model organism for the production of lipopetides. Nevertheless ... [more ▼]

Abstract : The design of a new single species biofilm bioreactor has been investigated. Bacillus subtilis S499 has been chosen as a model organism for the production of lipopetides. Nevertheless, considering the surface active properties for this kind of metabolite, processes based on submerged culture in stirred-tank bioreactor involve the use of important amount of antifoam and therefore downstream processes are tedious. In this work, an original process was developed with an experimental setting leading to the suppression of foam formation during the culture. B. subtilis S499 makes a biofilm on a stainless steel structured packing in the top of a bioreactor, nutrient and oxygen supply being carried out by the media recirculation as liquid film on the packing. Lipopeptides secreted by biofilm are accumulated in the liquid phase under the packing and can reach concentrations as high as 800 mg/l. The colonization of the packing by the biofilm has been monitored by X-ray tomography. [less ▲]

Detailed reference viewed: 122 (30 ULg)
Full Text
See detailBall milling control: the reconciliation of macroscopic SensoMag® data with microscopic optical information.
Leroy, Sophie ULg; Köttgen, Axel ULg; de Haas, Bernard et al

Poster (2012, February 08)

Detailed reference viewed: 74 (11 ULg)
Full Text
See detailImpact of cultivation practices on soil respiration
Dufranne, Delphine ULg; Vancutsem, Françoise ULg; Bodson, Bernard ULg et al

Poster (2012, February 08)

In addition to its, evident, food supply function, agriculture is subjected to various pressures and has to respond to many challenges like reducing its CO2 emissions, maintaining or improving the soil ... [more ▼]

In addition to its, evident, food supply function, agriculture is subjected to various pressures and has to respond to many challenges like reducing its CO2 emissions, maintaining or improving the soil quality, maintaining productivity, sequestrating of the carbon stock in soil... Cultivation practices are known to induce a modification of soil organic matter quantity, quality and spatial distribution, which may impact dry matter decomposition kinetics. In order to bring answers to these questions, a multidisciplinary project (SOLRESIDUS) was set up by the University of Liege, Gembloux Agro-Bio Tech in collaboration with Walloon Agricultural Research Centre (CRA-W). The aim was to investigate the impact of cultivation practices (tillage and residue restitution) on crop growth, yield and environment, as well as on soil properties and on activities. In the present study, we focused on the impacts on soil CO2 fluxes. The experimental site is situated in Gembloux, in the Belgian loamy region. The plot is divided into 4 latin squares where two tillage modalities (plough after 2 stubble breaking vs only 2 stubble breaking) and two straw management practices (restitution vs. exportation) were compared. For 3 years, soil respiration was measured with automatic and manual dynamic soil chambers. Moreover, soil respiration was measured as well in cropping zone (total respiration) as in root exclusion zones created with root exclusion cylinders (heterotrophic respiration). As first results, we observed: -a significantly higher flux in plots with residue restitution, which is clearly explained by the larger amount of organic carbon prone to decomposition; -a decrease of standardized heterotrophic respiration (linked with residue decomposition) during growing seasons; -no significant differences in soil respiration between tillage modalities after 3 growing seasons. The experiment is still in progress, more years being necessary in order to evaluate the long-term impacts of cultivation practices on soil respiration. [less ▲]

Detailed reference viewed: 77 (8 ULg)
Full Text
See detailRISQUES DE POLLUTION LIES À LA PULVERISATION DES PESTICIDES
Boukhalfa, Hassina dite Hafida ULg

Poster (2012, February 03)

L'étude de la dispersion des pesticides est fondamentale pour diminuer les pollutions environnementales mais elle s'avère particulièrement complexe. L’application de pesticides consiste généralement en la ... [more ▼]

L'étude de la dispersion des pesticides est fondamentale pour diminuer les pollutions environnementales mais elle s'avère particulièrement complexe. L’application de pesticides consiste généralement en la pulvérisation d’une bouillie liquide constituée d’eau, de matière active et d’adjuvants. La taille et la vitesse initiales des gouttes produites en sortie de buse conditionnent fortement le transport (hors cible: dérive: pollution de l’air) ainsi que le dépôt de ces gouttes (hors cible: pollution de l’eau et des sols). La pollution de l'air par les pesticides est l'un des grands problèmes environnementaux aux quels est confrontée l'agriculture, et la réversibilité de ses effets sur l'environnement et la santé est encore peu connue. Lors des traitements phytosanitaires, une partie relativement importante des produits pulvérisés est perdue dans l'environnement. La toxicité des pesticides est reconnue mais, au contraire des niveaux mesurés dans les eaux destinées à l'alimentation en eau potable, les teneurs en pesticides dans l'air ambiant ne sont pas actuellement normés ou réglementés. Les risques pour la santé dépendent de la toxicité des matières actives et de leurs concentrations dans les milieux d'exposition (air, eau, aliments). Dans le but de pouvoir estimer les risque de pollution de l'air par les pesticides nous avons étudié l'influence de quelque paramètres sur la répartition des jets de pulvérisation issus d'un pulvérisateur à pression de liquide à jet projeté, à savoir: la pression, la vitesse du vent, la hauteur des buses et le type de buse. Les résultats obtenus on permit de mettre en évidence la contribution du réglage du matériel de pulvérisation en la quantité de pertes en produit pulvérisé et d'en déduire approximativement le risque de pollution environnementale. [less ▲]

Detailed reference viewed: 128 (29 ULg)
Full Text
See detailQuantifications en supergéométrie
Leuther, Thomas ULg

Poster (2012, February)

Le poster présente de façon vulgarisée certaines idées sous-jacentes à la recherche de quantifications invariantes en supergéométrie.

Detailed reference viewed: 49 (17 ULg)
Peer Reviewed
See detailLower impact of blue light on non-visual brain functions in older subjects
Daneault, V; Vandewalle, Gilles ULg; Hébert, M et al

Poster (2012, February)

Detailed reference viewed: 13 (3 ULg)
Full Text
Peer Reviewed
See detailARE CAPABILITY INDICES USEFULL TO ASSESS ANALYTICAL METHODS VALIDITY ?
Rozet, Eric ULg; Bouabidi, Abderrahim ULg; Talbi, M. et al

Poster (2012, February)

Analytical methods capability evaluation can be a useful methodology to assess the fitness of purpose of these methods for their future routine application. However, care on how to compute the capability ... [more ▼]

Analytical methods capability evaluation can be a useful methodology to assess the fitness of purpose of these methods for their future routine application. However, care on how to compute the capability indices has to be made. Indeed, the commonly used formulas to compute capability indices such as Cpk, will highly overestimate the true capability of the methods. Especially during methods validation or transfer, there are only few experiments performed and, using in these situations the commonly applied capability indices to declare a method as valid or as transferable to a receiving laboratory will conduct to inadequate decisions. In this work, an improved capability index, namely Cpk-tol and the corresponding estimator of proportion of non conforming results ( ) is proposed. Through Monte-Carlo simulations, they have been shown to greatly increase the estimation of analytical methods capability in particular in low sample size situations as encountered during methods validation or transfer. Additionally, the usefulness of this capability index is illustrated through several case studies covering applications commonly encountered in the pharmaceutical industry. Finally a methodology to determine the optimal sample size required to validate analytical methods is also given using the proposed capability metric. [less ▲]

Detailed reference viewed: 119 (6 ULg)
Full Text
Peer Reviewed
See detailCOMBINATION OF INDEPENDENT COMPONENT ANALYSIS, DESIGN OF EXPERIMENTS AND DESIGN SPACE FOR A NOVEL METHODOLOGY TO DEVELOP CHROMATOGRAPHIC METHODS
Rozet, Eric ULg; Debrus, Benjamin ULg; Lebrun, Pierre ULg et al

Poster (2012, February)

As defined by ICH [1] and FDA, Quality by Design (QbD) stands for “a systematic approach to development that begins with predefined objectives and emphasizes product and process understanding and process ... [more ▼]

As defined by ICH [1] and FDA, Quality by Design (QbD) stands for “a systematic approach to development that begins with predefined objectives and emphasizes product and process understanding and process control, based on sound science and quality risk management”. A risk–based QbD–compliant approach is proposed for the robust development of analytical methods. This methodology based on Design of Experiments (DoE) to study the experimental domain models the retention times at the beginning, the apex and the end of each peak corresponding to the compounds of a mixture and uses the separation criterion (S) rather than the resolution (RS) as a Critical Quality Attribute. Stepwise multiple linear regressions are used to create the models. The estimated error is propagated from the modelled responses to the separation criterion (S) using Monte Carlo simulations in order to estimate the predictive distribution of the separation criterion (S) over the whole experimental domain. This allows finding ranges of operating conditions that will guarantee a satisfactory quality of the method in its future use. These ranges define the Design Space (DS) of the method. In chromatographic terms, the chromatograms processed at operating conditions within the DS will assuredly show high quality, with well separated peaks and short run time, for instance. This Design Space can thus be defined as the subspace, necessarily encompassed in the experimental domain (i.e. the knowledge space), within which the probability for the criterion to be higher than an advisedly selected threshold is higher than a minimum quality level. Precisely, the DS is defined as “the multidimensional combination and interaction of input variables (e.g., material attributes) and process parameters that have been demonstrated to provide assurance of quality” [1]. Therefore, this DS defines a region of operating conditions that provide prediction of assurance of quality rather than only quality as obtained with traditional mean response surface optimisation strategies. For instance, in the liquid chromatography there is a great difference in e.g. predicting a resolution (RS) higher than 1.5 vs. predicting that the probability for RS to be higher than 1.5 (i.e. P(RS> 1.5)) is high. The presentation of this global methodology will be illustrated for the robust optimisation and DS definition of several liquid chromatographic methods dedicated to the separation of different mixtures: pharmaceutical formulations, API and impurities/degradation products, plant extracts, separation of enantiomers, … References [1] International Conference on Harmonisation (ICH) of Technical Requirements for Registration of Pharmaceuticals for Human Use, Topic Q8(R2): Pharmaceutical development, Geneva, 2009. [less ▲]

Detailed reference viewed: 185 (9 ULg)
Full Text
See detailPOST-COMBUSTION CO2 CAPTURE: Global Process Simulation and Solvent Degradation
Léonard, Grégoire ULg; Lepaumier, Hélène; Blandina, Fabrice et al

Poster (2012, February)

One of the biggest upcoming challenges concerning both environmental and energy systems engineering is the control and limitation of greenhouse gas emissions due to human activity. Fossil fuels-fired ... [more ▼]

One of the biggest upcoming challenges concerning both environmental and energy systems engineering is the control and limitation of greenhouse gas emissions due to human activity. Fossil fuels-fired power plants are in this context one of the main contributors due to the large amounts of CO2 emitted. Different technologies have been developed for capturing CO2 from such power plants. This work focuses on post-combustion CO2 capture by reactive absorption into amine solvents like monoethanolamine (MEA). The main drawback of this technology is actually the high energy requirement of the process, especially for solvent regeneration. It is then highly interesting to model the capture process so that optimal operating conditions could be approached by simulation thus reducing the number of expensive experimental tests. Thanks to the simulation, it has been possible to identify the most influent process variables and to optimize their value. It was also possible to study the impact of process modifications on the global capture efficiency. The improvements studied allowed for a reduction by up to 14% of the process exergy consumption. Another major drawback of the post-combustion CO2 capture is solvent degradation, which can be due to thermal as well as oxidative mechanisms. Degradation affects the CO2 capture process since it may cause corrosion, foaming and fouling, possibly inducing a decrease of the solvent efficiency and high additional operating costs due to solvent replacement. In order to study degradation of conventional amine solvents as well as degradation of novel solvents, a degradation test rig has been built at the University of Liège in collaboration with the company Laborelec, member of the GDF SUEZ group. First results show that degradation obtained on this lab installation can be compared to degradation results observed on CO2 capture pilot installation. The final objective of this thesis is to make a link between degradation and simulation. Experimental data obtained on the degradation test rig will be implemented into the existing simulation model so that optimal operating conditions considering both process energy efficiency and solvent degradation can be determined. [less ▲]

Detailed reference viewed: 110 (8 ULg)
Full Text
Peer Reviewed
See detailRepeated cycles of DSS inducing a chronically relapsing inflammation: A novel model to study fibrosis using in vivo MRI T2 relaxometry
Breynaert, C; Dresselaers, T; Cremer, J et al

Poster (2012, February)

Detailed reference viewed: 24 (2 ULg)
Full Text
Peer Reviewed
See detailQUALITY BY DESIGN COMPLIANT METHOD VALIDATION
Rozet, Eric ULg; Boulanger, B.; Hubert, Philippe ULg

Poster (2012, February)

Analytical method validation is a mandatory step to evaluate the ability of developed methods to provide accurate results for their routine application in order to trust the critical decisions that will ... [more ▼]

Analytical method validation is a mandatory step to evaluate the ability of developed methods to provide accurate results for their routine application in order to trust the critical decisions that will be made with them. Even if several guidelines exist to help perform analytical method validations (ICH Q2R1 [1], USP <1225> [2], …) there is still the need to clarify the meaning and interpretation of analytical method validation criteria and methodology. Indeed, actually method validation is mostly realised as the traditional check list implementation of e.g. the ICH Q2R1 or USP <1225> method validation requirements. However, within the trend of Quality by Design [3], there is the need to switch from this traditional vision to an analytical method validation really adding value and providing a high level of assurance of analytical methods results reliability. Yet, different interpretations can be made of the validation guidelines as well as for the definitions of the validation criteria. This will lead to diverse experimental designs implemented to try fulfilling these criteria. Finally, different decision methodologies can also be interpreted from these guidelines. Therefore, the risk that a validated analytical method may be unfit for its future purpose will depend on a personal interpretation of these guidelines. The objective of this presentation is thus to show that analytical method validation should be planned and performed by first starting with the end in mind: what is the objective of the analytical methods under study? In such a way analytical method validation is coherent with the actual Quality by Design regulatory expectations. The risk of having validated an analytical method unfit for its purpose is strongly reduced as well as the risk of generating Out of Specification (OOS) results due to an unfit method. References [1] International Conference on Harmonisation (ICH) of Technical Requirements for registration of Pharmaceuticals for Human Use, Topic Q2 (R1): Validation of Analytical Procedures: Text and Methodology, Geneva, 2005. [2] USP 33 NF 28 S1, U.S. Pharmacopeia, 2007. USP–NF General Chapter <1225>. [3] International Conference on Harmonisation (ICH) of Technical Requirements for Registration of Pharmaceuticals for Human Use, Topic Q8(R2): Pharmaceutical development, Geneva, 2009. [less ▲]

Detailed reference viewed: 158 (10 ULg)
Peer Reviewed
See detailDoes pupil constriction under blue and green monochromatic light exposure change with age?
Daneault, V; Vandewalle, Gilles ULg; Hébert, M et al

Poster (2012, February)

Detailed reference viewed: 21 (0 ULg)
Peer Reviewed
See detailA single synthetic small molecule that generates force against a load
Lussis, Perrine ULg; Svaldo-Lanero, Tiziana; Bertocco, Andrea et al

Poster (2012, February)

Biological molecular machines are able to rectify random thermal motions to generate directional force and carry out tasks on both the molecular and macroscopic length scales1. Although some artificial ... [more ▼]

Biological molecular machines are able to rectify random thermal motions to generate directional force and carry out tasks on both the molecular and macroscopic length scales1. Although some artificial nanomachines have been synthesized2 and used to collectively carry out mechanical tasks3, so far there have been no direct measurements of mechanical processes at the single-molecule level. Here we report measurements of the mechanical work performed by a synthetic molecule less than 5 nm long. We show that biased Brownian motion of the sub-molecular components in a hydrogen bonded [2]rotaxane4 -a molecular ring threaded onto a molecular axle- can be harnessed to generate significant directional forces. We used the cantilever of an atomic force microscope to apply a mechanical load to the ring during single-molecule pulling–relaxing cycle. The ring was pulled along the axle, away from the thermodynamically favoured binding site, and was then found to travel back to this site against an external load of 30 pN5. Using fluctuation theorems6, we were able to relate the measurements of the work done at the level of individual molecules to the free energy change measured previously by ensemble measurements. The results show that individual rotaxane molecules can generate directional forces of similar magnitude to those generated by natural biological machines, and extend the capabilities of AFM-based single molecule mechanics to the world of small molecules. It opens up the possibility of testing modern theories of non-equilibrium statistical mechanics, such as Jarzynski’s equality7 and the Crooks fluctuation theorem6, in single-molecule AFM measurements. 1. Schilva, M. (ed.) Molecular Motors (Wiley-VCH, Weinheim, 2003). 2. Kay, E. R., Liegh, D. A. & Zerbetto, F., Angew. Chem. Int. Ed. 46, 72-191 (2007). 3. Berna, J., Leigh, D. A., Lubomska, M., Mendoza, S. M., Pérez, E. M., Rudolf, P., Teobaldi, G. & Zerbetto, F., Nature Mater. 4, 704-710 (2005). 4. Kay, E. R. & Liegh, D. A., Top. Curr. Chem. 262, 133-177 (2005). 5. Lussis, P., Svaldo-Lanero T., Bertocco, A., Fustin C-A., Leigh, D. A., Duwez A-S., Nature Nanotech. 6, 553-557 (2011). 6. Crooks, G.E., Phys.Rev.E, 60, 2771-2726 (1999) 7. Jarzynski, C., Phys.Rev.Lett., 78, 2690-2693 (1997) [less ▲]

Detailed reference viewed: 12 (1 ULg)