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See detailIsolation of bacteriophages against Klebsiella pneumoniae and in vivo activity
Thiry, Damien ULg; Passet, Virginie; Dufour, Nicolas et al

Poster (2016, September)

Klebsiella pneumoniae is a bacterial pathogen able to induce severe healthcare-associated or community-acquired infections in humans and animals. The constant emergence of antibiotic resistant strains ... [more ▼]

Klebsiella pneumoniae is a bacterial pathogen able to induce severe healthcare-associated or community-acquired infections in humans and animals. The constant emergence of antibiotic resistant strains reinforces the need to find alternatives to antibiotic treatments. The use of bacteriophages is a promising approach. The aim of this study was to isolate bacteriophages directed against K. pneumoniae strains and to test their efficacy in a murine model. Bacteriophages against five different K. pneumoniae (2 of capsular type K1 and K2 and 1 undetermined) were isolated and purified from waste water collected in Paris area. The morphology of plaques (zones of bacterial killing) was recorded and several of them were purified three times by successive replating. Phage titers were determined by serial dilutions on their respective hosts as well as on 18 other Klebsiella strains to identify their host range. Kinetics of bacterial lysis were monitored during 15h at 3 multiplicities of infection, in triplicates. For in vivo experiment, a total of 10 mice were inoculated with 200 µl of K. pneumoniae (4.6E+07 CFU) by oral gavage and the level of K. pneumoniae in fecal samples was monitored for 10 days. Five mice did not receive any treatment and 5 other mice received a cocktail of three bacteriophages (8E+07 PFU) at day 4 post-inoculation. A total of 54 bacteriophages were isolated and purified with titers ranging from 2E+5 to 3.6E+10 PFU/ml. The host range study showed that bacteriophages against K. pneumoniae have a specificity related to the capsular type of their bacterial host. Lysis kinetics of bacteria suggested that different phages were isolated. Despite difficulties with the murine intestinal model, evidence was obtained that bacteriophages are able to reduce intestinal carriage. Our results show that bacteriophages isolated against K. pneumoniae are specific for a given capsular type, although further studies are necessary to provide more details on this capsular specificity and its molecular determinants. To fully address the in vivo potential of phages, a reliable mouse model of intestinal carriage of K. pneumoniae strains needs to be established. [less ▲]

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See detailSingle-Molecule Force Spectroscopy on Synthetic Helical Nanoarchitectures
Devaux, Floriane ULg; Li, Xuesong; Huc, Ivan et al

Poster (2016, September)

Inspired by the many folded conformations of the molecular machineries in nature, chemists have been developing the syntheses of artificial folded molecular architectures, namely foldamers. The ... [more ▼]

Inspired by the many folded conformations of the molecular machineries in nature, chemists have been developing the syntheses of artificial folded molecular architectures, namely foldamers. The investigation of these molecules using AFM-based Single Molecule Force Spectrosocopy (SMFS) allows the elucidation of both mechanochemical properties and conformational dynamics on the unimolecular scale in solution. The stepwise synthesis of aromatic oligoamide-based foldamers was designed to produce well-defined helically-folded molecular architectures. A PEO tether was coupled to one end of the foldamer. SMFS pulling experiments on this system yielded specific and reproducible force-extension patterns characteristic of single foldamers. Those patterns were further analyzed to determine unfolding forces and dynamics as well as to propose mechanistics hypotheses of the unfolding process. Several helical foldamers presenting variable lengths were considered. The force values measured for those foldamers are higher than those previously measured in natural biopolymers showing a high stability under a load and a propensity for the development of emergent properties. In addition, the increased stability of these aromatic oligoamide foldamers was confirmed by the observation of almost instantaneous reversibility of the unfolding under load. [less ▲]

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See detailExperimental Assessment of The Influence of Interface Geometries on Structural Response
Dossogne, Tilàn ULg; Jerome, Trevor; Lancereau, Damien et al

Poster (2016, September)

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See detailThe BCCM/ULC collection to conserve and study the biodiversity of Polar cyanobacteria
Wilmotte, Annick ULg; Renard, Marine ULg; Lara, Yannick ULg et al

Poster (2016, September)

The BCCM/ULC public collection of Cyanobacteria has been funded since 2011 by the Belgian Science Policy Office. BCCM/ULC is currently holding 226 cyanobacterial strains, with 119 being of Antarctic ... [more ▼]

The BCCM/ULC public collection of Cyanobacteria has been funded since 2011 by the Belgian Science Policy Office. BCCM/ULC is currently holding 226 cyanobacterial strains, with 119 being of Antarctic origin (including 3 from the sub-Antarctic). The cyanobacteria constitute the bacterial phylum with the largest morphological diversity and their taxonomy is still a work in progress. In Polar Regions, Cyanobacteria represent key primary producers and are important drivers of the food webs in a wide range of aquatic to terrestrial habitats. For example, they build extensive benthic microbial mats in lakes and soil crusts in terrestrial biotopes. They have adapted to their environment, and may present interesting features to survive freeze/thaw cycles, seasonally contrasted light intensities, high UV radiations, dessication and other stresses. In this poster, we present the results of the 16S rRNA phylogenetic analysis for 76 Antarctic strains. This allows us to illustrate the diversity present in the collection, to detect lineages for which no genome has yet been sequenced, and to pinpoint taxonomic problems that should be addressed in a more comprehensive study. [less ▲]

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See detailComparaison de deux méthodes statistiques explorant la relation entre régimes alimentaires et risques cardiovasculaires.
Sauvageot, Nicolas ULg; Leite, Sonia; Donneau, Anne-Françoise ULg et al

Poster (2016, September)

Introduction L’analyse en composantes principales (ACP) et la régression à rangs réduits (RRR) sont deux méthodes de réduction de dimension permettant de construire des variables reflétant des régimes ... [more ▼]

Introduction L’analyse en composantes principales (ACP) et la régression à rangs réduits (RRR) sont deux méthodes de réduction de dimension permettant de construire des variables reflétant des régimes alimentaires. Les régimes alimentaires obtenus par ACP sont associés aux habitudes alimentaires de la population étudiée tandis que ceux obtenus par RRR sont associés à des indicateurs d’intérêt. L’objectif de cette étude est de comparer les deux approches quant aux régimes alimentaires obtenus et à leurs associations avec les facteurs de risques cardiovasculaires (FRCV). Méthodologie Les données proviennent de l’étude interrégionale et transversale nutrition, environnement et santé cardiovasculaire (NESCAV) ayant pour but de décrire la santé cardiovasculaire de la grande région (Luxembourg, Lorraine et Wallonie). Les apports alimentaires ont été mesurés à l’aide d’un questionnaire de fréquence alimentaire et 2298 individus ont été retenus pour cette analyse. Les indicateurs d’intérêt retenus pour l’approche RRR sont les FRCV usuels (obésité, hypertension, diabète, dyslipidémie). Résultats Nous avons trouvé que les régimes alimentaires consommés par la population et ceux associés au FRCV étaient similaires. Les régimes riches en fruits, fruits secs et oléagineux, légumes, huile d’olive, graisse riche en oméga 6, thé, et ceux pauvres en aliments frits, viandes, charcuteries, soda, plats préparés, bières étaient associés à une diminution des FRCV. Les autres régimes caractérisés par des apports élevés en aliments frits, viandes, abats, bières, vins, apéritifs et liqueurs et de faibles apports en céréales, sucres et soda étaient associés à une augmentation des FRCV. Conclusions L’utilisation des deux méthodes est utile pour obtenir des informations permettant d’élaborer de nouvelles recommandations alimentaires. Les régimes alimentaires identifiés dans cette étude sont à la fois associés aux habitudes alimentaires de la population et aux FRCV. [less ▲]

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See detailFunctional properties of extracellular polysaccharides produced by Enterobacter A47 grown on agro-food industry by-products
Antunes, Silvia; Freitas, Filomena; Alves, Vitor et al

Poster (2016, September)

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See detailDomestic tools, hafting, and the evolution of technology: The Upper Palaeolithic of Hohle Fels as a case study
Taipale, Noora ULg; Conard, Nicholas J.; Rots, Veerle ULg

Poster (2016, September)

Innovations relevant to human evolution often involve subsistence technology, which can affect the success of individual groups, and Homo sapiens in general. However, Palaeolithic technologies include ... [more ▼]

Innovations relevant to human evolution often involve subsistence technology, which can affect the success of individual groups, and Homo sapiens in general. However, Palaeolithic technologies include more than just hunting tools, and a proper understanding of hunter-gatherer ways of living requires knowledge of the organisation of diverse tasks and activities, including the manufacture and maintenance of tools and other equipment. One central aspect of technological evolution is the development of tool hafting [1, 2], which is not only restricted to hunting and gathering implements, but also affects so-called domestic tool categories. We present the results of an on-going project that focuses on hafting and use of stone tools in the Upper Palaeolithic through detailed functional analysis of selected assemblages from European key sites (Hohle Fels, Abri Pataud, Maisières-Canal), which have yielded rich lithic and organic assemblages from secure chronological contexts. Here the focus is on classic Upper Palaeolithic tool categories, such as endscrapers and burins, from the Gravettian and Magdalenian levels of the cave site Hohle Fels (Germany) [3, 4]. We suggest that domestic tools can offer a valuable source material, since for most of them, hafting is not a necessity as it is for spear and arrow tips. An increase in hafting implies an increase in time investment, which has implications for task organisation and specialisation. The Hohle Fels assemblage offers an interesting case study for temporal changes (or continuity) in the frequency and techniques of tool hafting. The projectile technology shows a clear shift from the Gravettian to the Magadalenian, marked by the introduction of a microlithic technology (backed bladelets). For other tool categories, the changes seem more subtle. Our goal is to characterise the tools used in manufacture and maintenance tasks, and to evaluate whether the Gravettian to Magdalenian transition witnesses changes in tool design and use that go beyond hunting equipment. The observed differences between tool classes and time periods are explained with a reference to details of tool use, such as the rate of edge wear development and stone tool exhaustion, as well as shifts in treatment of organic raw materials. The results suggest that domestic tools can aid in understanding long-term technological evolution, and create a baseline against which we can (re)assess the role of shifts observed in technologies that are more susceptible to morphological change, such as projectiles. References: [1] Rots, V., 2013. Insights into early Middle Palaeolithic tool use and hafting in Western Europe: The functional analysis of level IIa of the early Middle Palaeolithic site of Biache-Saint-Vaast (France). J. Archaeol. Sci. 40, 497–506. [2] Barham, L., 2013. From Hand to Handle: The First Industrial Revolution. Oxford University Press, Oxford. [3] Conard, N. J., Bolus, M., 2003. Radiocarbon dating the appearance of modern humans and timing of cultural innovations in Europe: New results and new challenges. J. Hum. Evol. 44, 331–371. [4] Taller, A., Bolus, M., Conard, N. J., 2014. The Magdalenian of Hohle Fels Cave and the Resettlement of the Swabian Jura after the LGM. In: Otte, M., Le Brun-Ricalens, F. (Eds.), Modes de contacts et de déplacements au Paléolithique eurasiatique: Actes du Colloque international de la commission 8 (Paléolithique supérieur) de l'UISPP, Université de Liège, 28–31 mai 2012. Centre National de Recherche Archéologique, Luxembourg. [less ▲]

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See detailA new method for identifying experimental and Palaeolithic hafting adhesives using GC×GC-HRTOFMS
Cnuts, Dries ULg; Perrault, Katelynn ULg; Dubois, Lena ULg et al

Poster (2016, September)

Hafting adhesives can be seen as an indication of the cognitive and technical capabilities of the manufacturers and therefore play a key role in the debate on human evolution [1], [2]. These adhesives are ... [more ▼]

Hafting adhesives can be seen as an indication of the cognitive and technical capabilities of the manufacturers and therefore play a key role in the debate on human evolution [1], [2]. These adhesives are mainly from plant origin (resins, gums or tar) and are often mixed with beeswax and other additives in order to make them less brittle. Archaeological evidence indicates that these adhesives were already in use in the Paleolithic from at least 120.000 years ago [3]. Discoveries for this period are however very rare and only become abundant from the Neolithic onwards [4]. Their longer exposure to biochemical alteration processes limits the chance of survival in the archaeological record. If they are present on Paleolithic stone tools, they appear often in such small quantities that they are challenging to identify by traditional gas chromatography – mass spectrometry (GC-MS) or even to remove them effectively from the stone tool. The destructive nature of traditional GC-MS analysis can damage these rare samples for other analyses. Our study aims to overcome this problem by using headspace solid phase microextraction (HS-SPME) for sample extraction and analysis by comprehensive two-dimensional gas chromatography –high-resolution time-of-flight mass spectrometry (GC×GC-HRTOFMS), which has the benefit of analyzing the volatile organic compound (VOC)s from the substance and it does not destroy the complete matrix of the adhesive. We present the results of a pilot study intended to examine the potential of this technique for analyzing Palaeolithic adhesives. The study involved (1) an examination of experimental compound adhesives (containing pine and spruce resin, acacia gum and birch tar; beeswax and additives like charcoal, flax or ochre), (2) a blind test on experimental samples to test the reliability of the method and to determine the minimal quantity necessary for analysis, and (3) the analysis of different Palaeolithic adhesives and of experimental samples of at least 15 years old. The analysis was done on extracted and non-extracted adhesives. A unique chromatographic fingerprint was obtained for all experimental adhesive samples. The VOC profile of these adhesives proved to be extremely complex and therefore benefitted significantly from multidimensional separation techniques. GC×GC-HRTOFMS provided an optimal chromatographic separation of adhesive components. HRTOFMS data was used in order to obtain high-resolution mass spectral data to contribute to compound identification. Our study demonstrates that GC×GC-HRTOFMS is a well suited method for identifying small quantities of compound adhesives with significant potential for Palaeolithic contexts. The additional sensitivity afforded by this technique in comparison to traditional GC-MS is a substantial benefit for these quantities. Furthermore, by only analyzing the VOCs of the adhesives, these rare archeological samples are not destroyed and can still be used for other types of analysis. [1] L. Wadley, ‘Compound-Adhesive Manufacture as a Behavioral Proxy for Complex Cognition in the Middle Stone Age’, Curr. Anthropol., vol. 51, no. s1, pp. S111–S119, Jun. 2010. [2] L. Barham, From Hand to Handle: The First Industrial Revolution. Oxford: Oxford University Press, 2013. [3] P. P. A. Mazza, F. Martini, B. Sala, M. Magi, M. P. Colombini, G. Giachi, F. Landucci, C. Lemorini, F. Modugno, and E. Ribechini, ‘A new Palaeolithic discovery: tar-hafted stone tools in a European Mid-Pleistocene bone-bearing bed’, J. Archaeol. Sci., vol. 33, no. 9, pp. 1310–1318, Sep. 2006. [4] M. Regert, ‘Investigating the history of prehistoric glues by gas chromatography-mass spectrometry.’, J. Sep. Sci., vol. 27, no. 3, pp. 244–54, Feb. 2004. [less ▲]

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See detailPlant esterified oxylipins: structure – function relationship
Genva, Manon ULg; Andersson, Mats X.; Nasir, Mehmet Nail ULg et al

Poster (2016, September)

In the present work, high quantities of arabidopsides were extracted and purified from Arabidopsis thaliana L.

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See detailChemical profiling of major components in natural waxes to elucidate their roles in liquid oil structuring
Diem Doan, Chi; Ming To, Chak; Lynen, Frederik et al

Poster (2016, September)

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See detailHow reliable are the models to study recent climate change ? A study of heat/cold waves and radiative fluxes trends over 1900-2010 using the model MAR in Belgium
Wyard, Coraline ULg; Fettweis, Xavier ULg; Scholzen, Chloé ULg

Poster (2016, August 29)

This research aims to assess the ability of the regional climate model MAR ("Modèle Atmosphérique Régional") to reconstruct the observed twentieth century climatology of extreme events and solar radiation ... [more ▼]

This research aims to assess the ability of the regional climate model MAR ("Modèle Atmosphérique Régional") to reconstruct the observed twentieth century climatology of extreme events and solar radiation in Belgium, as a necessary condition for reliable future projections. Simulations were performed by forcing MAR with several reanalyses: the ERA40/ERA-Interim, the ERA-20C and the NCEP/NCAR-v1. The results suggests that increasing air temperature would have generated decreasing relative humidity which would have lead to a decrease in cloudiness and an increase in solar downward radiation. This research illustrates the dependency between RCMs and their forcings. The forcing reanalyses can generate divergent trends while contrary to Global Climate Models (GCM), the reanalyses assimilate observations and are supposed to represent the same climate. [less ▲]

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See detailThe influence of background noise on vocal loading parameters in music theory teachers
Schiller, Isabel ULg; Morsomme, Dominique ULg; Sfez, Lou et al

Poster (2016, August 23)

Background: Music theory teachers, who teach rhythm, singing and other music-related skills and topics, depend greatly on a well-functioning voice. Unlike other schoolteachers, who primarily use their ... [more ▼]

Background: Music theory teachers, who teach rhythm, singing and other music-related skills and topics, depend greatly on a well-functioning voice. Unlike other schoolteachers, who primarily use their voice as a pedagogic tool, music theory teachers also use it as an instrument. Furthermore, they often engage in vocally demanding free-time activities requiring a singing voice. To date, few studies have specifically looked at the voice use of music theory teachers. This study aims (1) to measure the background noise level and the amount of vocal loading affecting this specific population, and (2) to describe the influence of background noise on vocal loading parameters. Methods: Thirteen French-speaking music theory teachers (9 females and 4 males) working in a music school were monitored for one workweek, using the VoxLog voice dosimeter (Sonvox). To investigate the professional and extra-professional environments, all subjects wore the dosimeter from early morning until the end of the day. The parameters analysed were background noise level, duration of phonation, sound pressure level (SPL) and fundamental frequency (F0) of voice. Results: Overall, the mean background noise level was 75.2 dB (SD=5.4). We measured higher background noise level at work (mean=78.2 dB, SD=5.8) than in the extra-professional environment (mean=72.2 dB, SD=5.2). As expected, a rise in background noise was accompanied by a significant rise in voice SPL in both males and females (r=.61, p<.001). A significant correlation between background noise and F0 was found in females (r=.41, p=.002), but not in males (r=.39, p=.055). Furthermore, our data exhibit a significant correlation between background noise and duration of phonation (r=.05, p<.001). Conclusion: Our data suggest, that in class, music theory teachers must cope with background noise levels that dramatically exceed the limit of 35 dB recommended by the WHO (Inserm, 2006). High background noise levels lead to an increase in voice SPL, a phenomenon known as the Lombard effect (Inserm, 2006). In female subjects, we also observed a rise in F0 further to high background noise. Like Ternström, Södersten, and Bohman’s (2002) study, our data indicate that high background noise levels increase the duration of phonation. In a noisy environment, subjects seem to prolong the voiced segments of speech to make themselves understood. In other words, high background noise levels result in higher vocal loading. In the long run, this may increase the risk of voice disorders such as hyperfunctional dysphonia or vocal fold pathologies consecutive to repeated microtrauma in music theory teachers. [less ▲]

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See detailOverhanging Constraints in Addivitive Manufacturing Using Two Different Tools
Bauduin, Simon ULg; Collet, Maxime ULg; Duysinx, Pierre ULg

Poster (2016, August 23)

Topology optimization is widely used as a design tool for advanced application in mechanical, aerospace and automotive industries. This technique offers an optimal distribution of a predetermined amount ... [more ▼]

Topology optimization is widely used as a design tool for advanced application in mechanical, aerospace and automotive industries. This technique offers an optimal distribution of a predetermined amount of material in a given design space. In the last years, a lot of efforts has been invested into the development of high performance methods such as homogenization, SIMP or BESO. However as the state of the art in manufacturing experiences evolution, a coupling between topology optimization and additive manufacturing is needed. Additive manufacturing has numerous advantages that fits the characteristics of topology optimized designs. It can manufacture highly complex design without high cost increase and furthermore continuous density material of the SIMP method could be manufactured by lattice structures. With all the opportunities given by the additive manufacturing the urge to bind the last one to topology optimization is heavily required. Specific constraints related to manufacturing issues have to be taken into account such as the need of supports structures to ensure a good heat evacuation during the manufacturing process, as well as to hold up overhanging section. Some researches have been done to try to include this constraint in the optimization problem such as Leary and al or Andrew T. Gaynor. However this work focuses on 2 different methods (projection scheme and mechanical approach) to tackle the overhanging problem and compare them . [less ▲]

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See detailA Comparison between four Techniques to Measure Cardiac Output
Pironet, Antoine ULg; Dauby, Pierre ULg; Chase, J. Geoffrey et al

Poster (2016, August 17)

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See detailCASTLE4D : The castle of Franchimont
Luczfalvy Jancsó, Andrea ULg; Hoffsummer, Patrick ULg; Billen, Roland ULg et al

Poster (2016, August 16)

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See detailTechniques et Méthodes nucléaires : Application de la Spectrométrie Gamma au Cameroun
Moyo N., Maurice; Kayo, Steve; Ngelem M., Eric J. et al

Poster (2016, August 04)

L’imaginaire populaire est de plus en plus pessimiste au sujet du mot nucléaire, utilisées selon eux, uniquement pour détruire, en cas de guerre. Une idée reçue, mais presque imposée par l'attitude des ... [more ▼]

L’imaginaire populaire est de plus en plus pessimiste au sujet du mot nucléaire, utilisées selon eux, uniquement pour détruire, en cas de guerre. Une idée reçue, mais presque imposée par l'attitude des pays développés qui donnent l'impression de recourir au nucléaire, le plus souvent, à des fins militaires. Pourtant, les applications du nucléaire sont utiles dans des domaines aussi variés que l'agriculture, la médecine, la détection des fuites dans les barrages, la surveillance de la qualité de l'air, des eaux, des sols, des matériaux de construction, des denrées alimentaires etc. Au Cameroun, l'utilisation des rayonnements ionisants (énergie nucléaire) est en pleine croissance. Ce, spécifiquement dans les domaines médical et industriel. La radioprotection est de plus en plus l’objet des recherches et des mesures au Cameroun. Des techniques d’analyse nucléaires sont également utilisées pour déterminer les risques radiologiques lies aux rayonnements naturels provenant de l’environnement. Dans ce cadre, l’unité de recherche « Physique Fondamentale » de l’université de Douala en collaboration avec l’ANRP (Agence Nationale de RadioProtection) utilise la spectrométrie gamma pour quantifier et qualifier l’exposition des camerounais aux rayonnements. Deux mémoires de master ont à cette occasion révéler le niveau d’exposition due aux rayonnements provenant du sol de l’Université de Douala d’une part et d’autre part l’exposition due aux matériaux de construction dans la ville de Douala. Les études sur les matériaux de construction (ciment utilisé dans la ville de Douala) ont permis d’observer que l’activité spécifique dans les échantillons de ciment varie d’un radionucléide à l’autre. L’estimation des paramètres radiologiques comme (l’activité du radium équivalent Raeq, l’indice du risque externe (Hex) et interne (Hin), le taux de dose absorbée dans l’air et la dose effective annuelle (AEDE) ont montré que l’utilisation comme matériaux de construction du ciment analysé était sans risque particulier. [less ▲]

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See detailSarcoptic mange infection in red foxes (Vulpes vulpes) in Belgium
Volpe, Rosario ULg; Caron, Yannick ULg; Lesenfants, Christophe ULg et al

Poster (2016, August)

Eight cases of sarcoptic mange in foxes were reported during summer 2014 (n=3) and winter 2015 (n= 5) in Belgium. All animals came from the same restricted forest zones near urbanized areas and some of ... [more ▼]

Eight cases of sarcoptic mange in foxes were reported during summer 2014 (n=3) and winter 2015 (n= 5) in Belgium. All animals came from the same restricted forest zones near urbanized areas and some of them were discovered in private gardens (Forest District of Thuin, Hainaut, Belgium). Three of them were found dead, the others were shot for sanitary reasons. At necropsy, all of them presented large areas of alopecia and extensive skin lesions such as hyperkeratosis and suppurative lacerations. Animals presented poor body condition and some of them were severely emaciated (absence of visceral fat). Mange has profound influences on population since, if untreated, death follows in four to six months. In the present cases, cutaneous scrapings and histopathological examinations were systematically performed. Numerous parasites were observed in skin scrapings and marked dermo-epidermatitis with several parasites was observed in histopathological sections. These results suggest an outbreak of sarcoptic mange in red foxes in a limited area of the country. This is a first record for the country. Furthermore, investigations on lungs and digestive tracts performed on 3 of these foxes revealed they were also infected by parasites transmissible to pets and/or humans: Angiostrongylus vasorum was observed in the respiratory tract of one fox whereas Toxocara canis, Uncinaria stenocephala, Taenia spp. and Echinococcus multilocularis worms were detected in the digestive tract. In conclusion, urban foxes represent a source of parasites of public health and veterinary importance and foxes surveillance should be strengthened in these areas. [less ▲]

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See detailCharacterization of Leptolyngbya and Phormidium diversity in Antarctic biotopes
Lara, Yannick ULg; Durieu, Benoit ULg; Borderie, Fabien et al

Poster (2016, August)

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See detailCyanobacterial diversity in soil crusts in the Sör Rondane Mountains
Namsaraev, Zorigto; Mano, Marie-José; Wilmotte, Annick ULg

Poster (2016, August)

Antarctica is the only continent that is dominated by microbial (cyanobacteria and algae) and lower plant (predominantly mosses and lichens) communities. Cyanobacteria are photosynthetic bacteria that ... [more ▼]

Antarctica is the only continent that is dominated by microbial (cyanobacteria and algae) and lower plant (predominantly mosses and lichens) communities. Cyanobacteria are photosynthetic bacteria that require solar light, liquid water, air and some mineral nutrients for growth. They serve as primary producers of organic matter in Antarctic ecosystems providing energy to other physiological groups of microorganisms and invertebrates. Cyanobacteria form macroscopically visible crusts or thin biofilms on the surface of soils and rocks, or occupy endolithic niches in Antarctic mountains. Mountains exposed above the ice sheet could have remained ice-free during glaciation maxima in Antarctica. They could serve as a refuge for terrestrial biodiversity and potential source for recolonization of surrounding habitats during glacier retreat. Cyanobacterial diversity in habitats located above 1 km a.s.l. was studied in several Antarctic locations. These include: the Vinson Massif in Ellsworth Mountains (2000-2500 m a.s.l.), Beacon (1176 m a.s.l.) and University Valleys (1700 m a.s.l.) in the "stable upland zone" of the McMurdo Dry Valleys (Southern Victoria Land) and the Sör Rondane Mountains (1370-1700 m a.s.l.) (Yergeau et al., 2007; Wood et al., 2008; Fernandez-Carazo et al., 2012). The goal of our work was to study cyanobacterial diversity of cyanobacteria in the Sör Rondane Mountains in the vicinity of Belgian Princess Elisabeth Station. Previous estimates of the diversity showed the presence of 10 morphotypes and 13 OTUs of cyanobacteria in 10 samples of biofilms and microbial crusts (Fernandez-Carazo et al., 2012). We performed a broader sampling and studied cyanobacterial diversity using DGGE with cyanospecific primers and microscopy. In 126 samples, we observed 15 morphotypes of cyanobacteria. 28 representative samples were selected for molecular analyses that revealed the presence of 28 OTUs (groups of 16S rRNA sequences sharing at least 97,5% sequence similarity). Comparison with other mountainous areas of Antarctica showed that the Sör Rondane Mountains harbor a significantly higher cyanobacterial diversity. Molecular analysis of the cyanobacterial diversity in Beacon Valley didn't show the presence of cyanobacteria (Wood et al., 2008), though a strain of Chroococcidiopsis sp. (CCMEE 134) was isolated from a sample collected there (Billi et al., 2011). A strain of Chroococcidiopsis sp. (CCMEE 171-A789-2) was also isolated from samples collected in University Valley (Cumbers & Rothschild, 2014). 5 OTUs of cyanobacteria were detected in samples collected in Ellsworth Mountains despite of the presumably harsher climate (78°31′S latitude compared to 77°49′S for Beacon Valley) and higher altitude (Yergeau et al., 2007). No reliable climate data are available for the discussed areas, except for the Sor Rondane Mountains. We propose that the higher diversity of cyanobacteria detected near the Princess Elisabeth Station could be explained by a more intensive sampling or by a more northern location of the area (72°0′S). [less ▲]

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See detailMicroalgae diversity along an Antarctic glacier forefield
Stelmach Pessi, Igor ULg; Rybalka, Natalia; Friedl, Thomas et al

Poster (2016, August)

Glacier retreat due to global warming has been observed in all the cryosphere [1], systematically exposing new terrestrial ecosystems that had previously been covered by ice. Primary succession, i.e. the ... [more ▼]

Glacier retreat due to global warming has been observed in all the cryosphere [1], systematically exposing new terrestrial ecosystems that had previously been covered by ice. Primary succession, i.e. the assembly of biological communities on newly exposed habitats and their change over time, can be studied along glacier forefields, where distance from the glacier terminus is used as a proxy for time since deglaciation [2]. The study of microbial succession is still at its infancy, but understanding the relationships between microbial communities and soil development will provide us with crucial knowledge on how they influence and respond to changes in environmental conditions. Here, we investigated the structure of microalgal communities along a deglaciation gradient in the forefield of Collins Glacier (Fildes Peninsula, King George Island, Maritime Antarctica). [less ▲]

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See detailThe BCCM/ULC collection: a Biological Ressource Center to give access to the Antarctic cyanobacterial diversity
Wilmotte, Annick ULg; Renard, Marine ULg; Lara, Yannick ULg et al

Poster (2016, August)

On the Antarctic continent, Cyanobacteria represent the key primary producers and the main drivers of the food webs in a wide range of aquatic to terrestrial habitats. For example, they build benthic ... [more ▼]

On the Antarctic continent, Cyanobacteria represent the key primary producers and the main drivers of the food webs in a wide range of aquatic to terrestrial habitats. For example, they build benthic microbial mats in lakes and soil crusts in terrestrial biotopes. They may present interesting features to survive freeze/thaw cycles, sea-sonally contrasted light intensities, high UV radiations, dessication and other stresses. The BCCM/ULC public collection funded by the Belgian Science Policy Office since 2011 aims to gather a representative portion of the polar cyanobacterial diversity with different ecological origins (limnetic microbial mats, soil crusts, cryoconites, endoliths, etc.). It makes it available for researchers to study the taxonomy, evolu-tion, adaptations to harsh environmental conditions, and genomic make-up. It pres-ently includes 226 cyanobacterial strains, with 119 being of Antarctic origin (cata-logue: http://bccm.belspo.be/catalogues/ulc-catalogue-search). The morphological identification shows that the strains belong to the orders Synechococcales, Oscillatoriales, Pleurocapsales, Chroococcidiopsidales and Nostocales. We present here the molecular datasets showing the diversity of the BCCM/ULC strains, studied on the basis of the 16S rRNA gene. A selection of strains was also characterized by sequencing of rpoC1, recA, and gyrA genes after amplification with newly designed primers. Our results mainly show that 25 OTUs included strains of Antarctic origin. Moreo-ver, strains identified as members of the genera Leptolyngbya or Phormidium ap-pear in several lineages. This supports the need to revise these polyphyletic genera with a simple filamentous morphology. A certain divergence of some Antarctic strains from related strains isolated from other regions can also be observed. It suggests that a portion of the Antarctic cyanobacterial flora may have evolved in-dependently from the cyanobacteria in other continents. [less ▲]

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Peer Reviewed
See detailParcours migratoire et résilience : ressources et contraintes perçues par des réfugiés syriens et afghans
Vereshchagin, Anton ULg; Glowacz, Fabienne ULg

Poster (2016, August)

Les chiffres du Haut-Commissariat des Nations Unies pour les réfugiés indiquent une augmentation considérable du flux migratoire en Europe depuis 2010. Cette tendance s’explique notamment par une violence ... [more ▼]

Les chiffres du Haut-Commissariat des Nations Unies pour les réfugiés indiquent une augmentation considérable du flux migratoire en Europe depuis 2010. Cette tendance s’explique notamment par une violence persistante dans des pays tel que l’Afghanistan et l’évolution du conflit en Syrie. Dans le cadre d’une approche écosystémique, les contraintes perçues et rappelées par les sujets ayant « survécu » à la « traversée » migratoire et aux micro-traumatismes associés ont été mises en perspectives avec, les motivations liées à cette migration et les ressources perçues par les migrants. Notre étude de type exploratoire se base sur la rencontre avec 15 sujets âgés de 21 à 67 ans : 7 afghans et 8 syriens (13 hommes et 2 femmes) résidant dans des structures d'accueil pour demandeurs d'asile et hors structure, en Belgique. Des entretiens semi-structurés ont été menés en anglais et en russe et trois questionnaires ont été administrés : le locus de contrôle (1966), le sentiment d'auto-éfficacité (1997) et le soutien social perçu (1985). L'analyse des discours a mis en évidence différents types de motivations à la migration ne prédéterminant pas nécessairement la complexité du voyage qui apparait davantage dépendante des contextes situationnels, des opportunités et diverses contraintes. Par contre, les motivations semblent associées aux ressources perçues. Sur base de l’analyse du récit de la trajectoire, ainsi que des questionnaires, plusieurs facteurs de protection et de résilience ont été identifiés. Nous avons également proposé une nouvelle adaptation du modèle transthéorique de changement (DiClemente et Prochaska, 1982) au processus migratoire. [less ▲]

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See detailL’Hadrianus de Montserrat (P.Monts.Roca III, inv.162 → - 165 ↓) : une source nouvelle sur la Colonia Claudia Ara Agrippinensium ?
Berg, Tatiana ULg

Poster (2016, August)

Sixième partie du codex miscellaneus de Montserrat (P.Monts.Roca III, inv.162 → - 165 ↓ = MP3 2998.11 = LDAB 552, papyrus, 2e moitié IVe siècle), qui présente la particularité de contenir des textes à la ... [more ▼]

Sixième partie du codex miscellaneus de Montserrat (P.Monts.Roca III, inv.162 → - 165 ↓ = MP3 2998.11 = LDAB 552, papyrus, 2e moitié IVe siècle), qui présente la particularité de contenir des textes à la fois grecs et latins, profanes et chrétiens, tous écrits par la même main, le récit latin en prose Hadrianus relate notamment le passage de l’empereur Hadrien dans la ville de Cologne, dont il évoque des realia. Après les avoir répertoriées et avoir évalué leur authenticité, le poster met en évidence l’apport du texte à la connaissance de la Colonia Claudia Ara Agrippinensium et de son autel des Ubiens. [less ▲]

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Peer Reviewed
See detailProofing & Reduction Strategies Used by Emergency Residents to Manage Fatigue-related Risk
Berastegui, Pierre ULg; Ghuysen, Alexandre ULg; Nyssen, Anne-Sophie ULg

Poster (2016, July 29)

Fatigue and sleep loss are typically associated with psychomotor and cognitive impairment resulting in poorer task performance. Most of these studies are conducted in controlled settings and involve the ... [more ▼]

Fatigue and sleep loss are typically associated with psychomotor and cognitive impairment resulting in poorer task performance. Most of these studies are conducted in controlled settings and involve the completion of experimental tasks. Only a few field studies involving exhausted residents have been conducted over the past decade, and they yielded to contradictory results (Ellman et al., 2004). One of the key factors that could be involved in the non-linear relationship between fatigue and performance in specific work context reside in the mobilization of Fatigue Proofing Strategies. FPS are adaptive and protective risk-reduction behaviors that improve the resilience of a system of work (Dawson et al., 2012). In this study, we aimed to identify and classify proofing strategies mobilized by EMS residents using an inductive content analysis approach. EMS residents reported a range of strategies for reducing subjective level of sleepiness (reduction strategies, n=15) or managing its consequences (proofing strategies, n=17). Content analysis yielded to three sub-categories of proofing strategies: Behavioral Compensation (n=8), Error’s Opportunity Reduction (n=5) and Error’s Consequences Mitigation (n=4). Our results show that EMS residents use both types of strategies although none of the proofing strategies were part of their training program. Despite the current informal use, there is significant potential for implementation of more formal processes. [less ▲]

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See detailAharonov-Bohm oscillations of bosonic matter-wave beams in the presence of disorder and interaction
Chrétien, Renaud ULg; Dujardin, Julien; Petitjean, Cyril ULg et al

Poster (2016, July 27)

We study the one-dimensional (1D) transport properties of an ultracold gas of Bose-Einstein condensed atoms through Aharonov-Bohm (AB) rings. Our system consists of a Bose-Einstein condensate (BEC) that ... [more ▼]

We study the one-dimensional (1D) transport properties of an ultracold gas of Bose-Einstein condensed atoms through Aharonov-Bohm (AB) rings. Our system consists of a Bose-Einstein condensate (BEC) that is outcoupled from a magnetic trap into a 1D waveguide which is made of two semi-infinite leads that join a ring geometry exposed to a synthetic magnetic flux φ. We specifically investigate the effects both of a disorder potential and of a small atom-atom contact interaction strength on the AB oscillations. The main numerical tools that we use for this purpose are a mean-field Gross-Pitaevskii (GP) description and the truncated Wigner (tW) method. We find that a correlated disorder suppress the AB oscillations leaving thereby place to Aronov-Al’tshuler-Spivak (AAS) oscillations. The competition between disorder and interaction leads to a peak inversion at Φ = π, that is a signature of a coherent backscattering (CBS) peak inversion. This is confirmed by truncated Wigner simulations. [less ▲]

Detailed reference viewed: 29 (3 ULg)
See detailBiofilm fermentation for the production of insect pathogenic fungi
Bawin, Thomas ULg; Francis, Frédéric ULg; Delvigne, Frank ULg

Poster (2016, July 27)

Currently, integrated pest management that aims to reduce the use of synthetic insecticides by considering all appropriate alternative methods, is promoted. In that context, insect pathogenic fungi could ... [more ▼]

Currently, integrated pest management that aims to reduce the use of synthetic insecticides by considering all appropriate alternative methods, is promoted. In that context, insect pathogenic fungi could be developed as biopesticides in two ways: spores but also metabolites that are recognized as virulence factors. Targeting adequate fermentation method is an important requirement to obtain fungal products (i.e. spores, enzymes and metabolites) of biotechnological interest. The 'Microbial Processes and Interactions' laboratory has developed an innovative fermentation technology (referred to as ‘biofilm fermentation’) involving the growth of fungal biomass on inert supports that are immersed in a liquid nutrient medium. Confining fungal biomass on immersed inert structures provides a hybrid production system aiming to keep a solid-state physiology for sporulation and secretion of metabolites while controlling fermentation parameters. This research project proposes to transfer this technology to culture insect pathogenic fungi, such as Metarhizium anisopliae, for the production of spores and insecticidal metabolites. Development stages include the qualitative and quantitative characterization of its impact on insecticidal products as well as scale-up to industrial level. [less ▲]

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Peer Reviewed
See detailQuantitative characterization and calibration of salt water intrusion models with electrical resistivity tomography
Beaujean, Jean; Hermans, Thomas ULg; Vandenbohede, Alexander et al

Poster (2016, July 26)

Groundwater quality and coastal ecosystems in coastal areas are among the most vulnerable as they are threatened by excessive groundwater withdrawals, sea level rise and storm events potentially leading ... [more ▼]

Groundwater quality and coastal ecosystems in coastal areas are among the most vulnerable as they are threatened by excessive groundwater withdrawals, sea level rise and storm events potentially leading to salt water intrusions or infiltration into fresh water aquifers. The environmental protection and sustainable management of these groundwater resources often involves the development and calibration of a groundwater model subsequently used to forecast the total dissolved solid content (TDS). However, groundwater models are often built based on a limited number of sparse data due to borehole availability. Geophysical methods can provide spatially and temporally distributed data for hydrogeological modeling at relatively limited costs. In particular, electrical resistivity tomography (ERT) is very sensitive to the conductivity of pore water which is directly linked to the TDS content. The method is therefore well-suited for the monitoring of salt water intrusions. However, the inversion of ERT data involves a regularization process so that the resulting tomogram is only an estimate of the true resistivity distribution, suffering from smoothing and varying resolution. In many cases, the interpretation of ERT remains qualitative and skewed. In this contribution, we propose two different methods to improve the information content that can be extracted from ERT data. First, we show with a field example from Belgium how alternative regularization methods can be developed to integrate independent information into the inversion process of ERT. This enabled us to obtain a resistivity distribution much closer to the one observed in validation boreholes. Then, a site-specific petrophysical relationship is used to derive the TDS content of the aquifer from ERT tomograms. This can be directly used as input in the calibration process of a hydrogeological model. We also show how it is possible to counterbalance the effect of resolution loss with depth for surface ERT by filtering the results relative to their sensitivity. We show that this filtering is mandatory to use the ERT-derived information for calibrating a hydrogeological model. In a second example, we show how a fully coupled inversion approach can be used to directly invert geophysical data together with hydrogeological data for the calibration of hydrogeological models. At each iteration of the calibration, the simulated TDS content is transformed in a resistivity distribution using a parameterized petrophysical relationship and forward geophysical modeling yields the geophysical response. We show that this approach enables to better estimate the hydrogeological parameters of the simulated coastal aquifer than with an uncoupled approach if the conceptual model is sufficiently representative. With those two examples, we demonstrate the usefulness of ERT in the monitoring of salt water intrusions, both qualitatively to identify most vulnerable zones and quantitatively to estimate ERT-derived TDS contents or geophysical data and calibrate hydrogeological models. An innovative approach may consist in a conjunctive use of filtered geophysically-derived and geophysical data within the coupled hydrogeophysical inversion framework. Such an uncoupled-coupled approach based on a resolution threshold approach may offer a promising developing trend in hydrogeophysical inversion. [less ▲]

Detailed reference viewed: 77 (4 ULg)
See detailImpacts of entomopathogenic fungi on biology and behaviour of the invasive Brown Marmorated Stink Bug (Hemiptera, Pentatomidae)
Fingu Mabola, Junior Corneille ULg; Serteyn, Laurent ULg; Bawin, Thomas ULg et al

Poster (2016, July 25)

Halyomorpha halys St˚al (Hemiptera, Pentatomidae) is an invasive stink bug coming from Eastern Asia. Besides causing important yields losses in orchards, crop and vegetable fields, it overwinters inside ... [more ▼]

Halyomorpha halys St˚al (Hemiptera, Pentatomidae) is an invasive stink bug coming from Eastern Asia. Besides causing important yields losses in orchards, crop and vegetable fields, it overwinters inside houses as agglomerates of dozens. In Europe, this Brown Marmorated Stink Bug (BMSB) was accidentally introduced in Switzerland in 2007 and has been later observed in surrounding countries (France, Italy, Germany). Based on the current US situation, we can reasonably fear that BMSB will have colonized most of Europe countries in less than a decade. If we already discern a few fungus strains that are efficient against BMSB, very little is known about their actual impact on the insect itself. So we investigated the in- fluence of a fungal infection on insect development parameters and behaviour. Olfactometry was settled to investigate the dispersion and aggregation trends, while electropenetography was used to assess the feeding behaviour. Our results will be discussed to present changes according to healthy/fungus-infected status, in relation to potential biological control for that pest. [less ▲]

Detailed reference viewed: 54 (11 ULg)
Peer Reviewed
See detailThe verbal overshadowing effect in children and adults is unrelated to the specific content of descriptions
Vanootighem, Valentine ULg; Brédart, Serge ULg; Dehon, Hedwige ULg

Poster (2016, July 21)

Verbal descriptions of unfamiliar faces have been found to impair later identification of these faces in children and adults, a phenomenon known as the “verbal overshadowing effect” (VOE, Schooler and ... [more ▼]

Verbal descriptions of unfamiliar faces have been found to impair later identification of these faces in children and adults, a phenomenon known as the “verbal overshadowing effect” (VOE, Schooler and Engstler-Schooler, 1990). The present study thoroughly examined the person descriptive abilities of 7–8, 10–11, and 13–14-year-old children and adults and their influence on later identification performance. Our aim was to specifically assess the prediction of the “content” account suggesting that a verbal overshadowing arises because participants generate an inadequate verbal description and later rely upon it during retrieval. Results showed a verbal overshadowing effect in all age groups but neither accuracy, length nor content of descriptions were found to be associated with identification accuracy. [less ▲]

Detailed reference viewed: 71 (2 ULg)
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See detailNeural correlates of memory for internal thoughts versus external stimuli experienced in natural settings
Stawarczyk, David ULg; Jeunehomme, Olivier ULg; D'Argembeau, Arnaud ULg

Poster (2016, July 19)

To investigate the brain regions supporting the remembrance of internal thoughts versus external events, we asked participants to perform a short walk while wearing a lifelogging device that continuously ... [more ▼]

To investigate the brain regions supporting the remembrance of internal thoughts versus external events, we asked participants to perform a short walk while wearing a lifelogging device that continuously and automatically took pictures. In a subsequent fMRI session, they were shown brief sequences of pictures from their walk and were asked to remember either external events or internal thoughts that they experienced while walking. Results showed that remembering internal thoughts activated the medial prefrontal cortex and temporal poles to a greater extent than remembering external events, whereas remembering external events was associated with higher activation in lateral frontoparietal regions. These findings suggest that memory for internal thoughts involves the reactivation of brain regions supporting the initial formation of these thoughts. [less ▲]

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See detailStudy of the microbial diversity of microbial ring trials by metagenomic analysis : Quantification of alive bacteria by exclusion of dead bacteria
Fall, P.A.; Burteau, S.; Detry, E. et al

Poster (2016, July 19)

Detailed reference viewed: 11 (0 ULg)
Peer Reviewed
See detailRecollection versus familiarity in normal aging and in mild cognitive impairment: Impact of test format.
Simon, Jessica ULg; Gilsoul, Jessica ULg; SALMON, Eric ULg et al

Poster (2016, July 18)

The aim of this study was to investigate the impact of test format on recollection and familiarity in normal aging and in MCI. Seventy young participants, 65 younger-old, 53 older-old, and 13 MCIs were ... [more ▼]

The aim of this study was to investigate the impact of test format on recollection and familiarity in normal aging and in MCI. Seventy young participants, 65 younger-old, 53 older-old, and 13 MCIs were presented with forced-choice and yes/no visual recognition memory tasks with the Remember/Know/Guess paradigm. The young people had better recognition performance than younger-old, who performed better than older-old and MCIs. Recollection and familiarity declined progressively in healthy aging. In MCI, recollection was more affected than familiarity, but patients demonstrated a more liberal use of familiarity. Finally, test format did not influence strongly the results. Young people used recollection more often in the forced-choice task compared to the yes/no task. [less ▲]

Detailed reference viewed: 49 (3 ULg)
See detailMetagenetics and predictive microbiology: a new tool to understand the kinetics of microbial subpopulations in Belgian white pudding
Cauchie, Emilie ULg; Gand, Mathieu; Kergourlay, Gilles et al

Poster (2016, July 18)

Detailed reference viewed: 36 (15 ULg)
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See detailStatistical physics of memory driven systems
Hubert, Maxime ULg

Poster (2016, July 18)

For classical systems, statistical description is usually required when the dimension of the system phase space is important. This description is used when considering many body problems such as the ... [more ▼]

For classical systems, statistical description is usually required when the dimension of the system phase space is important. This description is used when considering many body problems such as the thermodynamical description of fluids, granular media or the diffusion of Brownian particles in the presence of a thermal reservoir. Can this limit be reached at the single particle level? We address this question by considering a single particle coupled to its own past, via a wave-mediated size-controllable memory, which stores the past trajectory of the particle. Such an object has been turn into reality by Couder et al [1,2] by using liquid bouncing droplets that interact with the waves they generate by impacting a liquid surface. In those experiments, the memory is made by stationary waves with a tunable damping time. The wave memory triggers various regime from individual self-propelled particle motion to structured chaos [3] or self-organization processes between a particle and its waves [4]. In the limit of a large amount of “souvenirs” stored in the wave field, we will show that the dynamics can be well described by the tools of non-equilibrium statistical mechanics. Both the dynamics of the particle and the wave-mediated memory are investigated. We show that, from the particle-point of view, the memory acts as a random force. The particle dynamics is adequately described by a Langevin equation for self-propelled systems. The corresponding Fokker-Planck equation shows that the memory can be seen as a thermal reservoir whose temperature is tuned via the amount of “souvenirs” in the dynamics. The features of this unusual wave-like thermal reservoir are investigated from an energetic and entropic perspective. We show that the global wave field is on average weaker that one would expect from superposition of random wave fields. This depletion originates from destructive interferences that the particle generates along its trajectory, corresponding to a kind-of minimization principle. [1] Y. Couder, S. Protière, E. Fort & A. Boudaoud, “Walking and orbiting droplets”, Nature, 437, 208 (2005). [2] A. Eddi, E. Sultan, J. Moukhtar, E. Fort, M. Rossi & Y. Couder, “Information stored in Faraday waves: the origin of a path memory”, J. Fluid Mech., 674, 433- 463 (2011). [3] S. Perrard, M. Labousse, E. Fort & Y. Couder, “Chaos driven by interfering memory”, Phys. Rev. Lett, 113, 104101 (2014). [4] S. Perrard, M. Labousse, M. Miskin, E. Fort & Y. Couder, “Self-organization into quantized eigenstates of a classical wave-driven particle”, Nat. Comm., 5, 3219 (2014). [less ▲]

Detailed reference viewed: 20 (2 ULg)
See detailGamma-Ray Spectrometry: Experimental Measurement and Monte Carlo Simulation using GEANT4 toolkit
Guembou Shouop, Cébastien Joel ULg; Ndontchueng Moyo, Maurice; Chene, Grégoire ULg et al

Poster (2016, July 13)

Nowadays the precision in the measurement has become a challenge for physicists. That is why in recent decades, the interest is very granted to simulation. Since 1940, the method Monte Carlo is more ... [more ▼]

Nowadays the precision in the measurement has become a challenge for physicists. That is why in recent decades, the interest is very granted to simulation. Since 1940, the method Monte Carlo is more useful for validation and even for prediction of the results of the experiment. The aim of this study is to validate experimental models. Our laboratories are equipped with HPGe gamma spectrometers for measuring the natural radioactivity, it becomes interesting to compare and even to improve the performance of our system. Geant4 is used for the construction of the geometry of detection, the physics processes and the primary particles. First and prliminary result was prsented in this paper. [less ▲]

Detailed reference viewed: 26 (3 ULg)
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Peer Reviewed
See detailCounting time measurement and statistics in gamma spectrometry: the balance
Guembou Shouop, Cébastien Joel ULg; Ndontchueng Moyo, Maurice; Chene, Grégoire ULg et al

Poster (2016, July 11)

Nuclear counting statistics at high count rate are assessed on a γ-ray spectrometer set-up. Our typical gamma spectrometry system consists of a High Purity Germanium (HPGe) detector, liquid nitrogen ... [more ▼]

Nuclear counting statistics at high count rate are assessed on a γ-ray spectrometer set-up. Our typical gamma spectrometry system consists of a High Purity Germanium (HPGe) detector, liquid nitrogen cooling system, preamplifier, detector bias supply, linear amplifier, analog-to-digital converter (ADC), multichannel storage of the spectrum, and data readout devices. Although the system is powerful enough for background measurements, it is important, nowadays, to have a great statistical in short time measurement: which is a challenge for scientists. The purpose of this study was to determine the average time for gamma spectrometry measurement. To detect Uranium, Thorium and their respective daughters and Potassium series with a relative related error less than 1%, it was found that it is necessary to count during a minimum of 24 Hours (86,400 s). This result is in accordance to the literature with planar geometry detector. These results conduct us to make the following three guidelines for selecting the detector best suited for an application: 1. The more detector material available (germanium semi-conductor), the higher the full-energy peak efficiency. 2. The smaller the distance between the detector and the source material, the higher the full- energy peak efficiency. 3. While better resolution gives a better MDA, the resolution contributes only as the square root to the MDA value, whereas the MDA is proportional to the full-energy peak efficiency. This idea came to us by comparing the spectra of measuring radioactivity lasts for 12 hours in the day that does not fully covered the night spectra for the same sample. The conclusion after several investigations became clearer: to remove all effects of radiation from outside (earth, sun and universe) our system, it is necessary to measure the background for 24, 48 or 72 hours. In the same way, the samples have to be measures for 24, 48 or 72 hours to be safe to be purified the measurement (equality of day and night measurement). It is also possible to not use the background of the winter in summer. Depend to the energy of radionuclide we seek, it is clear that the most important steps of a gamma spectrometry measurement are the preparation of the sample and the calibration of the detector. [less ▲]

Detailed reference viewed: 39 (6 ULg)
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See detailRestricted interests in autism with versus without speech onset delay : the importance of perceptually versus thematically organized interests
Chiodo, Liliane ULg; Majerus, Steve ULg; Eusèbe, Sandrine et al

Poster (2016, July 07)

Objectives : To explore whether autistic adults with vs without speech delay also differ in the perceptual vs thematic nature of their restricted interests.

Detailed reference viewed: 12 (3 ULg)
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See detailIntegrated microfluidic device for in line SERS detection for glyphosate and related metabolites
Emonds-Alt, Gauthier ULg; Malherbe, Cédric ULg; Monbaliu, Jean-Christophe ULg et al

Poster (2016, July 07)

The goal of this work is to develop a quantitative analytical method for the glyphosate and its major metabolite the aminomethylphosphonic acid (AMPA) by coupling microfluidics with surface enhanced Raman ... [more ▼]

The goal of this work is to develop a quantitative analytical method for the glyphosate and its major metabolite the aminomethylphosphonic acid (AMPA) by coupling microfluidics with surface enhanced Raman spectroscopy (SERS). This work is divided into 4 axes : (a) bimetallic nanoparticles synthesis in a microreactor, (b) nanoparticles functionnalisation, (c) SERS quantification of glyphosate/AMPA and (d) miniature prototype development composed of axes a to c. The first section aims at the synthesis of bimetallic nanoparticles (Au-Ag, Au-Cu and Ag-Cu) in a microfluidic device. This microfluidic device integrates a first section for the synthesis of monometallic nanoparticles (core) and a second section for the reductive deposition of a second metal (shell). The second axe of this work deals with the functionnalisation of nanoparticles to improve the selectivity of this method for the selected analytes. Two types of functionnalisation are studied : PEGylation (a) with multi-arm PEG ending with -SH and/or (b) with linear heterobifunctionnal PEG. The third axe consists in measuring quantitatively glyphosate and AMPA in different matrices, such as water, urine and fruit juice. Finally, the forth axe deals with the development of a portable detection system to perform on-site analysis. This prototype integrates the microfluidic device for nanoparticles synthesis, their functionnalisation, an injection port followed by a mixing section for the sample and an integrated Raman spectrometer for in-line analysis. [less ▲]

Detailed reference viewed: 48 (13 ULg)
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See detailNonlinear analysis of compliant mechanisms: application to tape springs
Dewalque, Florence ULg; Bruls, Olivier ULg

Poster (2016, July 07)

Brief summary of the mechanical behaviour of tape springs. Main results obtained by the means of finite element models. Description of the experimental set-up and results. See the extended abstract for ... [more ▼]

Brief summary of the mechanical behaviour of tape springs. Main results obtained by the means of finite element models. Description of the experimental set-up and results. See the extended abstract for more details. [less ▲]

Detailed reference viewed: 31 (4 ULg)
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See detailDevelopment and optimization of a TD-GC/MS methodology for detection and quantifi cation of furan released in air using of an experimental design.
Alsafra, Zouheir ULg; Scholl, Georges ULg; Romain et al

Poster (2016, July 07)

In the aim of understanding the way in which human is exposed to furan present in the air of an occupational area, an analytical method of Thermal desorption-gas chromatography/Mass spectrometry (TD-GC/MS ... [more ▼]

In the aim of understanding the way in which human is exposed to furan present in the air of an occupational area, an analytical method of Thermal desorption-gas chromatography/Mass spectrometry (TD-GC/MS) has been developed and optimized using a Plackett–Burman experimental design. This method was then used to study the phenomena of diffusion of furan released in air from a contamination source. This source of furan is simply a coffee machine located in a closed controlled room. Results show that furan concentration increases quickly over time after turning on the coffee machine until reaching a maxima. Then it starts to decrease slowly. On the other hand, concentration of furan seems to be identical everywhere in the conditioned room in each moment. [less ▲]

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See detailNovel butanol pretreatment significantly improves delignification and saccharification of different lignocellulosic biomasses
Schmetz, Quentin ULg; Teramura, Hiroshi; Jacquet, Nicolas ULg et al

Poster (2016, July 07)

Organosolv pretreatment using diluted acid and butanol allows the separation of cellulose, hemicelluloses and lignin into three distinct phases. The butanol process has been investigated on six different ... [more ▼]

Organosolv pretreatment using diluted acid and butanol allows the separation of cellulose, hemicelluloses and lignin into three distinct phases. The butanol process has been investigated on six different biomasses: tall fescue, sugarbeet pulp, sugarcane bagasse, beech wood, eucalyptus and Japanese cedar. Dilute acid pretreatment has been performed under similar conditions for comparison. [less ▲]

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See detailOptimisation de la production d’acide furan-2,5-dicarboxylique à partir de déchets verts pour la conception de plastiques bio-basés
Istasse, Thibaut ULg; Jacquet, Nicolas ULg; Richel, Aurore ULg

Poster (2016, July 06)

Afin de trouver des alternatives renouvelables aux produits issus de l’industrie pétrochimique, de nombreuses voies de recherches ont été explorées. Une voie prometteuse est la technologie des dérivés ... [more ▼]

Afin de trouver des alternatives renouvelables aux produits issus de l’industrie pétrochimique, de nombreuses voies de recherches ont été explorées. Une voie prometteuse est la technologie des dérivés furaniques. Parmi ces composés, le 5-hydroxyméthylfurfural (5-HMF) fait partie des molécules plateformes les plus importantes1. Il s’agit d’un produit de dégradation obtenu par déshydratation des hexoses2,3. Le 5-HMF peut servir de base à la conception de nombreuses molécules valorisables comme l’acide furan-2,5-dicarboxylique dont la structure proche de l’acide téréphtalique permet des applications dans la conception de polymères bio-basés3. L’acide furan-2,5-dicarboxylique respecte la législation REACH selon l’European Chemicals Agency4. Un rapport de l’EFSA de 2014 a démontré que cette substance ne posait pas de problème de toxicité lors de son utilisation comme monomère de base dans les plastiques d’emballage pour aliments5. Selon la société Avantium, le FDCA peut être utilisé pour produire un plastique entièrement bio-basé, le polyéthylène furanoate (PEF), qui affiche des performances supérieures à celle du poléthylène téréphtalate (PET) en termes de stabilité thermique, de propriétés mécaniques et de perméabilité aux gaz6. Si le FDCA peut être convertit en de nombreux produits à haute valeur ajoutée, il existe toutefois un frein majeur à son exploitation industrielle : son précurseur, le 5-HMF, n’est pas encore produit en grande quantité1. Ce problème est dû principalement à la déshydratation non sélective des sucres de la biomasse qui aboutit à de nombreux autres produits que le 5-HMF. La première difficulté à surmonter est donc la mise au point d’un procédé permettant de déshydrater de manière efficace et sélective les sucres de la biomasse. Le 5-HMF est également peu stable en milieu acide où il se décompose en acide formique et en acide lévulinique2. L'enjeu du projet de recherche présenté est donc l’optimisation de la production de 5-HMF à partir d’un ou plusieurs types de biomasses dans un premier temps, puis l’optimisation de la conversion du 5-HMF produit en FDCA. Les paramètres à prendre en compte sont notamment les sources de biomasse, l’efficacité des prétraitements concernant l’extraction des sucres, la sélectivité et l’efficacité de la conversion de ces sucres en 5-HMF (système mono- ou biphasique), l’étude de divers catalyseurs, le coût des traitements, etc… [less ▲]

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See detailEtude de la composition chimique de Pseudotsuga menziesii (Mirb.) Franco et évaluation de l’impact de divers prétraitements lignocellulosiques sur l’extraction de la lignine
Berchem, Thomas ULg; Schmetz, Quentin ULg; Jacquet, Nicolas ULg et al

Poster (2016, July 06)

La raréfaction des ressources fossiles est une certitude à l’heure actuelle. Il est donc primordial de trouver des voies de production plus durables pour des produits de consommation courante. Le ... [more ▼]

La raréfaction des ressources fossiles est une certitude à l’heure actuelle. Il est donc primordial de trouver des voies de production plus durables pour des produits de consommation courante. Le bioraffinage fait partie des solutions envisagées pour substituer les matériaux originaires de la filière pétrochimique. Dans cette optique, ce travail se focalise sur l’extraction et la caractérisation de la lignine à partir d’une biomasse présente en abondance en région Wallonne, Pseudotsuga menziesii (Mirb.) Franco (Douglas). Ce travail vise à montrer l’impact de divers prétraitements lignocellulosiques, tant en terme de rendements et de pureté d’extraction qu’au niveau de la modification de la structure et des propriétés des lignines. Ces différents paramètres sont évalués par des techniques gravimétriques (Klason), chromatographiques (chromatographie d’exclusion stérique) et spectroscopiques (RMN 2D HSQC). Pseudotsuga menziesii (Mirb.) Franco a été préalablement caractérisé par son taux de matière lignocellulosique (cellulose, hémicelluloses, lignine), ainsi que sa teneurs en cendres, en protéines et en extractibles (à l’eau et à l’éthanol). Les lignines natives ont été caractérisées par RMN 2D HSQC. [less ▲]

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See detailIdentifying wheat varieties with low acrylamide potential
Lecart, Brieuc ULg; Jacquet, Nicolas ULg; Anseeuw, Laurent et al

Poster (2016, July 05)

Maillard reactions are responsible for the formation of many compounds in food that have been baked at temperatures above 120°C1. Some of these compounds are sought for their contribution to the ... [more ▼]

Maillard reactions are responsible for the formation of many compounds in food that have been baked at temperatures above 120°C1. Some of these compounds are sought for their contribution to the organoleptic qualities of food but others, such as acrylamide, have been identified since 1986 as reprotoxic, genotoxic and carcinogenic in animals2. Synthesized from a chain reaction between free sugars and free asparagine, acrylamide has been found in many food such as products prepared from wheat flour1,3,4. The correlation between the amount of free sugars and free asparagine in raw food with the acrylamide content in the baked food has been well documented5. For this reason we compared the levels of 15 wheat varieties and identified wheat varieties with significantly lower level (=0.05) in acrylamide precursors. Those varieties could therefore be used preferentially in products intended for food. [less ▲]

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See detailHigh-temperature and quantitative XRD study of typical Westerwald clays (Germany)
Fontaine, François ULg; Fagel, Nathalie ULg

Poster (2016, July 05)

The Westerwald is one of the largest and oldest clay mining area of Germany. Those deposits were formed during the Eocene and Oligocene as a result of the weathering, erosion and redeposition of Devonian ... [more ▼]

The Westerwald is one of the largest and oldest clay mining area of Germany. Those deposits were formed during the Eocene and Oligocene as a result of the weathering, erosion and redeposition of Devonian rocks. During the Miocene, intense volcanic activities led to a large basalt cover, protecting the clays from the erosion. The fine fraction is mainly composed of kaolinite and illite, with the possible presence of interstratified I S. Other minerals such as quartz, feldspars, hematite, goethite or anatase are present in variable concentrations. Four typical Westerwald clays were chosen for this study: kaolinite-rich clay, kaolinite-illite clay, a red and a yellow firing clays. The first goal is to perform quantitative XRD using two different methods and to compare them: reference intensity ratio (RIR) and Rietveld (using Topas and BGMN). The second goal is the study of those samples using high-temperature XRD (HTXRD). The samples were heated up to 1250°C and a XRD pattern was obtained in situ every 100°C. The results show the temperatures of vitrification and formation of mullite and cristobalite varying from one sample to another, which is mainly linked to their flux concentration. [less ▲]

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See detailPIXE-PIGE analysis of Early Medieval Glass Artefacts at IPNAS cyclotron external beam line
Chene, Grégoire ULg; Van Wersch, Line ULg; Biron, Isabelle et al

Poster (2016, July 05)

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See detailL’intégration d’indicateurs biologiques dans un réseau de surveillance des sols afin d’améliorer le diagnostic de la qualité du sol – une étude de cas dans le sud de la Belgique (Wallonie)
Krüger, Inken ULg; Chartin, Caroline; van Wesemael, Bas et al

Poster (2016, July 05)

Les organismes du sol et leurs activités sont essentiels pour le fonctionnement de l’écosystème du sol et ils peuvent donc servir comme indicateurs de la qualité du sol. Des efforts ont récemment été ... [more ▼]

Les organismes du sol et leurs activités sont essentiels pour le fonctionnement de l’écosystème du sol et ils peuvent donc servir comme indicateurs de la qualité du sol. Des efforts ont récemment été menés pour intégrer les indicateurs biologiques de la qualité du sol dans les réseaux de surveillance régionaux/nationaux. Le but de cette étude était de déterminer des gammes de valeurs pour six indicateurs biologiques et deux quotients éco-physiologiques pour les sols agricoles. La respiration potentielle, la biomasse microbienne (carbone et azote), la minéralisation nette de l’azote, la diversité métabolique des bactéries du sol, l’abondance des vers de terre, le quotient microbien et le quotient métabolique ont été mesurés dans 60 sites dans des régions agricoles contrastées (différents types de sol et climat) et différentes utilisations de sol (prairies et cultures) sélectionnés d’un réseau de surveillance du carbone organique du sol (CARBOSOL). Les liens entre indicateurs biologiques et paramètres chimiques (le pH du sol, carbone organique total, soluble, labile et stable) sont analysés. Quatre des six indicateurs biologiques sélectionnés (respiration potentielle, biomasse microbienne (carbone et azote) et diversité métabolique des bactéries du sol) sont significativement plus élevés sous prairies que sous cultures. Les gammes de valeurs sont plus larges sous prairies que sous cultures. Les indicateurs biologiques sélectionnés ne sont pas significativement influencés par la région agricole. Les meilleures corrélations avec les paramètres chimiques ont été trouvées pour la respiration potentielle et la biomasse microbienne (carbone et azote). L’étude définit des gammes de valeurs pour les sols agricoles à l’échelle régionale (Wallonie) séparées par utilisation de sol (prairies et cultures) et présente une base solide pour l’établissement d’un réseau de surveillance de la qualité biologique du sol. [less ▲]

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See detailProgramme de soutien aux aidants de patients présentant la maladie d’Alzheimer : une étude de cas
Clesse, Audrey ULg; Missotten, Pierre ULg; Adam, Stéphane ULg

Poster (2016, July 05)

Il est largement reconnu que vivre au jour le jour avec un proche atteint de la maladie d’Alzheimer est une situation particulièrement éprouvante. La charge générée par cette maladie peut menée à des ... [more ▼]

Il est largement reconnu que vivre au jour le jour avec un proche atteint de la maladie d’Alzheimer est une situation particulièrement éprouvante. La charge générée par cette maladie peut menée à des états de fatigue psychologiques et physiques, voir au burnout, pour l’aidant. Plusieurs études sur la santé des aidants prenant en charge un proche dément ont montré qu’ils constituent, en comparaison aux personnes s’occupant d’un individu âgé non dément, une population à risque, notamment en termes de symptômes dépressifs, détresse psychologique ou de problèmes de santé. Ces constats alarmants justifient la mise en place de programmes de soutien visant à offrir un suivi thérapeutique aux personnes ayant un conjoint ou un parent présentant une démence de type Alzheimer. Nous présentons l’étude de cas de Mme C.G., fille d’une patiente âgée de 79 ans, ayant suivi le programme de soutien développé par Adam et al. (2009), basé sur l’approche de gestion du stress qui suggère l’utilisation de stratégies d’ajustement centrées sur la résolution de problèmes. Avant et après l’intervention, Mme C.G. a répondu à différents questionnaires examinant sa santé psychologique (MBI, BDI-II, STAI, etc.), sa manière de gérer la maladie de son parent (WCC, CAMI, SCQ, etc.) et l’état général de la patiente (ADRQL, IADL, NPI). La comparaison pré et post-intervention apporte des éléments positifs, notamment concernant l’amélioration de la qualité de vie de l’aidante, de son sentiment de compétence et d’efficacité à gérer la maladie au quotidien. Concernant le burnout, qui était la priorité de cette intervention, nous constatons que l’épuisement émotionnel de l’aidante tend à diminuer au cours des séances de counseling. Un autre constat particulièrement important concerne les changements familiaux opérés tout au long de la thérapie ; ce qui pose question quant à la réorganisation de la dynamique familiale. Ces résultats positifs démontrent l’importance de développer des programmes d’aide aux aidants grâce à une approche clinique globale et holistique de la situation, étant donné les composantes neuropsychologiques, cognitives et systémiques impliquées. [less ▲]

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See detailDroplet manipulation on fiber networks
Weyer, Floriane ULg; Pan, Zhao; Truscott, Tadd et al

Poster (2016, July)

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See detailMagnetocapillary self-assemblies: Swimming and micromanipulation
Grosjean, Galien ULg; Hubert, Maxime ULg; Lagubeau, Guillaume et al

Poster (2016, July)

Floating magnetic particles can self-assemble into structures, by a combination of a magnetic dipole-dipole interaction and an attraction due to the interfacial deformation. These structures are ... [more ▼]

Floating magnetic particles can self-assemble into structures, by a combination of a magnetic dipole-dipole interaction and an attraction due to the interfacial deformation. These structures are periodically deformed in a non reciprocal way using magnetic fields, which leads to controllable low Reynolds number locomotion. Such microswimmers provide a basis for micromanipulation applications such as transport of micro-objects, local mixing of fluids or surface cleaning. [less ▲]

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See detailPassive flutter suppression using a nonlinear tuned vibration absorber
Verstraelen, Edouard ULg; Gourc, Etienne ULg; Kerschen, Gaëtan ULg et al

Poster (2016, July)

A recent study showed that the addition of a linear tuned vibration absorber could increase the flutter speed of a rigid wing with pitch and flap degrees of freedom by about 35%. However, the absorber was ... [more ▼]

A recent study showed that the addition of a linear tuned vibration absorber could increase the flutter speed of a rigid wing with pitch and flap degrees of freedom by about 35%. However, the absorber was turning the initial super-critical bifurcation into a sub-critical one. This work shows numerically that adding a nonlinear restoring force to the absorber can restore the su- percritical behaviour of the bifurcation and further reduce the post-instability limit cycle amplitude. [less ▲]

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See detailHeavy methane to explain the unexplained recent methane growth ?
Bader, Whitney ULg; Strong, Kim; Walker, Kaley

Poster (2016, July)

Methane (CH4) is the second most important greenhouse gas emitted by human activities in the Earth’s atmosphere. Although it is roughly 200 times less abundant than carbon dioxide, it is a 28 times more ... [more ▼]

Methane (CH4) is the second most important greenhouse gas emitted by human activities in the Earth’s atmosphere. Although it is roughly 200 times less abundant than carbon dioxide, it is a 28 times more potent greenhouse gas. Approximately one fifth of the changes in the Earth’s balance energy caused by human-linked greenhouse gases since the beginning of industrialization (~1750) is due to methane. Methane is emitted by both natural sources and human activities. Indeed, methane can be emitted to the atmosphere through coal mining, oil and gas exploitation, rice cultures, domestic ruminant animals, biomass burning, waste management, wetlands, termites, methane hydrates and ocean. In the atmosphere, methane is mainly destroyed by the radical hydroxyl, also called the detergent of the atmosphere, and therefore plays a major role on the oxidizing capacity of the atmosphere. Since the beginning of the industrialization, atmospheric methane concentrations have increased by 260% to reach 1824 pbb in 2013. From the 1980s until the beginning of the 1990s, atmospheric methane was significantly on the rise, then stabilized during 1999-2006 to rise again afterwards. To this day, the source or sink responsible of this latter increase remains unexplained. Through each emission process, heavy molecules of methane (with one additional neutron either on a carbon or on one hydrogen atom) are emitted along methane (12CH4). The main heavy molecules of methane, called isotopologues (13CH4 and CH3D), are respectively ~110 and ~60 000 times less abundant than methane. Despite their small abundances, they give crucial information on the concentration of methane in the atmosphere and its evolution. Indeed, both isotopologues are emitted with specific emission ratio depending on the emission sources. Determining isotopic ratio of atmospheric methane is therefore a unique tracer of its budget. While the non-monotonous trend of methane is subject of an extensive number of studies, to our knowledge, no study of the isotopic ratio of methane derived from ground-based solar observations has been published to date. Measurements of heavy methane from Fourier Transform InfraRed spectra recorded with state of the art spectrometers installed at Eureka [Arctic, Canada] and Toronto [Ontario, Canada] along with analysis of observations collected by a portable instrument [Portable Atmospheric Research Interferometric Spectrometer for the Infrared, PARIS-IR], installed at Eureka will help fill this gap. Indeed, the produced time series, compared with the corresponding satellite observations (ACE-FTS) products will ease data interpretation and contribute to a global view of the question of isotopologues. [less ▲]

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See detailPolyurethane coatings in 20th century outdoor painted sculptures: discrimination of main systems by means of Py-GC-MS and ATR-FTIR
Defeyt, Catherine ULg; Schilling, Michael; Langenbacher, Julia et al

Poster (2016, July)

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See detailApplication of NIR hyperspectral imaging combined to chemometrics to assess the impact of tillage on the root system development of a winter wheat crop
Fraipont, Guillaume ULg; Eylenbosch, Damien ULg; Baeten, Vincent et al

Poster (2016, July)

This poster presents de results of a study of the influence of tillage on the root development of a winter wheat crop. The originality of this research lies in the application of an innovative root ... [more ▼]

This poster presents de results of a study of the influence of tillage on the root development of a winter wheat crop. The originality of this research lies in the application of an innovative root quantification method based on the near infrared hyperspectral imaging. [less ▲]

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See detailGeochemistry and mineralogy approaches to characterize brick and its lake sediments sources: Antioch Roman City (Southern Turkey)
El Ouahabi, Meriam ULg; Hubert, Aurelia ULg; Benjelloun, Yacine et al

Poster (2016, July)

The Roman aqueduct of Antioch-on-the-Orontes (Southern Turkey) is situated close to the Antioch city. This last is located near the Amik Lake (Lake of Antioch) and close to the junction between the active ... [more ▼]

The Roman aqueduct of Antioch-on-the-Orontes (Southern Turkey) is situated close to the Antioch city. This last is located near the Amik Lake (Lake of Antioch) and close to the junction between the active Dead Sea fault and the East Anatolian fault. During the Roman period, the Amik Plain was more densely occupied than at any time in its history [1]. The study focuses on the bricks and the lake sediments characterization in order to determine the source area as well as the technical production used at this period. For this purpose, several bricks were sampled on different parts of the city's aqueducts. Furthermore, a core of about 6 m of sediments was also collected from the dried Amik Lake. The bricks were characterized through a mineralogical (XRD) and chemical (PIXE-PIGE) approaches. Unfired clay fraction remained as inclusion in the brick was separated and then analysed using XRD. Geochemical composition and clay mineralogy were performed on the raw sediments from the Amik Lake in order to compare the source area. Technological test will be performed on the raw clay sediments from the Amik Lake in the purpose to understand the production techniques used at this time. The age of the brick production was previously dated to the Roman Period [2]. The synthesis of all the data attested the Amik Lake sediment as the raw material for the bricks of the aqueduct. Clay mineral composition from the Roman period deposited in the lake is smectite, illite, kaolinite and small amount of mixed-layer clays. The similar clays composition is found in the remained clays on the brick used for the aqueduct construction. Fast and heterogeneous firing practice characterized the manufacturing of these materials due to the rapid need for the materials during the post-seismic repairs after earthquakes that are mentioned in historical written works. [1] J. Casana, Geomorphology, 101, 429-442 (2008) [2] Y. Benjelloun, J. de Sigoyer, J. Carlut, A. Hubert-Ferrari, H. Dessales, H. Pamir, V. Karabacak, Comptes Rendus Geoscience, 347, 170-180 (2015) [less ▲]

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See detailGirls and Math Careers Expectations: Influence of Teacher Support and Motivational Variables
Jaegers, Doriane ULg; Lafontaine, Dominique ULg

Poster (2016, July)

Drawing on the expectancy-value theory, the three basic dimensions of instructional quality and the self-determination theory, this study examines the relation between teacher support, motivational ... [more ▼]

Drawing on the expectancy-value theory, the three basic dimensions of instructional quality and the self-determination theory, this study examines the relation between teacher support, motivational variables, course enrollment and career expectations in the domain of math. Gender differences are also investigated. Teacher support is seen as the fulfilment of the need of relatedness which is defined by the affective and academic quality of the teacher-student relationship. [less ▲]

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See detailInternal structures of clusters in driven granular gas
Noirhomme, Martial ULg

Poster (2016, July)

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See detailLaser Ultrasound for NDT: investigation of the generation beam shape
Languy, Fabian ULg; Perrard, Aurélie; Vandenrijt, Jean-François ULg et al

Poster (2016, July)

Usually laser ultrasonic systems use an infrared laser operating at 10 µm to generate the ultrasound in CFRP objects. However this system suffer from an important drawback: optical fiber cannot be used to ... [more ▼]

Usually laser ultrasonic systems use an infrared laser operating at 10 µm to generate the ultrasound in CFRP objects. However this system suffer from an important drawback: optical fiber cannot be used to transport the high energy beam from the laser output to the target which limits the flexibility of the system to investigated complex shaped objects. To overcome this issue, visible light can be used to generate ultrasound. In our case we use a fiber-coupled laser operating at 532 nm. The output end of the optical fiber is placed on an industrial robot arm. The investigated object remains stationary while the optical fiber mounted on the robot arm scan the object. This system offers large flexibility but laser generation at 532 nm is known to be less efficient than CO 2 system emitting at 10 µm. Increasing the visible pulse power is one of the options but optics and CRFF object will be damaged before the same echo level as CO2 generation can be obtained. An alternative solution consists in the investigation of the generation beam size and shape. We recently developed an optical design composed of an axicon lens able to generate annular beam. The diameter of the beam can be adapted. If the axicon lens is removed the optical system provides a disk whose diameter can also be adapted onto the investigated object. Ray-traycing simulations performed with ASAP and experimental beam profile investigated with a beam profiler show good agreement between theoretical and experimental optical design. An experimental comparison between ring and disk shapes will be presented. The comparisons take into account the beam diameter and the beam intensity but also the effect of the angle of incidence will be presented. [less ▲]

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See detailStudy of Mezoneuron benthamianum, a plant traditionally used against malaria in Guinea
Tchinda Tiabou, Alembert ULg; Loua, Jean; Esters, Virginie ULg et al

Poster (2016, July)

Despite some improvements in malaria control, this parasitic disease remains a major public health problem in many African countries, causing about 400 000 deaths/year through the continent, mainly by ... [more ▼]

Despite some improvements in malaria control, this parasitic disease remains a major public health problem in many African countries, causing about 400 000 deaths/year through the continent, mainly by children under the age of five (WHO, 2015). In Guinea, the leaves of Mezoneuron benthamianum Baill. are traditionally used to treat malaria (Traore et al., 2013) and showed a good antiplasmodial activity in an antiprotozoal in vitro screening (Traore et al., 2014), as well as promising results in a preliminary small-scale ethnomedical study (unpublished data), encouraging us to continue the study of this plant. The aim of this work was to evaluate the activity of M. benthamianum leaves extracts against P. falciparum using an in vitro test model (p-LDH assay) and to undertake a bio-guided fractionation to identify the compounds responsible for the activity. Hydroethanolic extracts (70% v/v) of M. benthamianum leaves showed a moderate in vitro activity against P. falciparum 3D7, with IC50 = 22.5 – 32.6 µg/ml, depending on the batch; while a dark precipitate formed during ethanol evaporation showed higher activity (IC50 = 6,5µg/ml). The bioguided fractionation was performed on this most active fraction and allowed the isolation of three diterpens, two flavonoids, resveratrol, gallic acid and its ethylester, β-sitosterol glucoside and pheophorbide derivatives. The active compounds belong to several phytochemical classes, including flavonoids, pheophorbide and gallic acid derivatives, contributing together to the global antiplasmodial activity of the hydroalcoholic extract against P. falciparum parasite. This study gives some concrete evidence to support the ethnopharmacological use of Mezoneuron benthamianum leaves extract in the management of malaria. The active compounds can be further studied for their antiplasmodial potential, as well as their suitability to be used as quality markers for the standardization of this herbal drug from the Guinean traditional pharmacopeia. [less ▲]

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See detailCoherent backscattering in the Fock space of Bose- and Fermi-Hubbard systems
Engl, Thomas; Dujardin, Julien; Tisserond, Emilie et al

Poster (2016, July)

Coherent backscattering generally refers to a significant and robust enhancement of the average backscattering probability of a wave within a disordered medium, which from a semiclassical point of view ... [more ▼]

Coherent backscattering generally refers to a significant and robust enhancement of the average backscattering probability of a wave within a disordered medium, which from a semiclassical point of view arises due to the constructive interference between backscattered trajectories and their time-reversed counterparts. We recently investigated the manifestation of this wave interference phenomenon in the Fock space of a disordered Bose-Hubbard system of finite extent [1], which can potentially be realized using ultracold bosonic atoms within optical lattices. Preparing the atoms in a well-defined Fock state of the lattice and letting the system evolve for a finite time will, for suitable parameters of the system and upon some disorder average over random on-site energies of the lattice, generally give rise to an equidistribution of the occupation probability within the energy shell of the Fock space that corresponds to the initial energy of the system, in accordance with the quantum microcanonical ensemble. We find, however, that the initial state is twice as often encountered as other Fock states with comparable total energy, which is a consequence of coherent backscattering [1]. Most recently, we showed that this phenomenon also arises in spin 1/2 Fermi-Hubbard rings that involve Rashba hopping terms (which combine inter-site hoppings with spin flips and arise from spin-orbit coupling), for which a newly developed semiclassical theory [2] correctly predicts a coherent enhancement of the occupation probabilities of the initial state and its spin-flipped counterpart. Moreover, performing a global spin flip within this Fermi-Hubbard system will give rise to significant spin echo peaks on those two Fock states, which is again a consequence of quantum many-body interference [3]. The semiclassical predictions of these enhancements and peaks are found to be in very good agreement with numerical findings obtained from the exact quantum time evolution within this Fermi-Hubbard system. [1] T. Engl, J. Dujardin, A. Argüelles, P. Schlagheck, K. Richter, and J. D. Urbina, Phys. Rev. Lett. 112, 140403 (2014). [2] T. Engl, P. Plößl, J. D. Urbina, and K. Richter, Theoretical Chemistry Accounts 133, 1563 (2014). [3] T. Engl, J. D. Urbina, and K. Richter, arXiv:1409.5684. [less ▲]

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See detailInterspecific variation of warning calls in piranhas: comparative analysis
Mélotte, Geoffrey ULg; Michel, Christian ULg; Vigouroux, Régis et al

Poster (2016, July)

Fish sounds are often considered as species-specific with unique temporal and spectral features. Differences between acoustic signals of closely related species could be considered as pre-zygotic barrier ... [more ▼]

Fish sounds are often considered as species-specific with unique temporal and spectral features. Differences between acoustic signals of closely related species could be considered as pre-zygotic barrier and could be related to the evolutionary history of the species. In the present study, sounds were recorded and compared in eight piranha species (Serrasalmus elongatus, Serrasalmus marginatus, Serrasalmus compressus, Serrasalmus manueli, Serrasalmus spilopleura, Serrasalmus rhombeus, Serrasalmus eigenmanni and Pygocentrus nattereri) in order to evaluate the potential role of acoustic communication as a driving force in the clade diversification. The same kind of sound-producing mechanism was found in all the species: sonic muscles originate on vertebrae and attach to a tendon surrounding ventrally the bladder. Contractions of the sound-producing muscles force swimbladder vibration. Having the same kind of sound-producing mechanism, the calling features of the eight piranha species show logically many common characteristics. In all the species, the calls are harmonic sounds composed of several pulses without inter-pulse interval. It was possible to discern species-specific sounds, but the differences among species could be, in part, explained by the size. Only the sounds of S. elongatus and S. manueli are really distinguishable from the other species. Serrasalmus elongatus differed by having a higher number of pulses and high-pitched fundamental frequency, whereas S. manueli differed by having long pulse periods and a low fundamental frequency. In the framework of this study, acoustic communication cannot be considered as the main driving force in the diversification process of piranhas. Behavioral studies are however needed to clearly understand the eventual role of the calls during the spawning events. [less ▲]

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See detailObservational signatures of past mass-exchange episodes in massive binaries : The cases of LSS 3074 and HD 17505
Raucq, Françoise ULg; Rauw, Grégor ULg; Gosset, Eric ULg et al

Poster (2016, July)

Mass and angular momentum exchanges through Roche Lobe Overflow interactions within close massive binaries are known to play an important role in the subsequent evolution of the components of such systems ... [more ▼]

Mass and angular momentum exchanges through Roche Lobe Overflow interactions within close massive binaries are known to play an important role in the subsequent evolution of the components of such systems, and produce several observational signatures, such as asynchronous rotation and altered chemical compositions, that remain once the stars detach again. We have started to investigate these effects in a sample of massive O-star binaries that are thought to have previously experienced a Case A Roche Lobe Overflow episode. Using phase-resolved spectroscopy, we perform the disentangling of the optical spectra of the two stars. The reconstructed primary and secondary spectra re then analysed with the CMFGEN model atmosphere code to determine stellar parameters such as the effective temperatures, surface gravities and rotational velocities, and to constrain the chemical composition of the components. In this contribution, we present the results of our analyses of LSS 3074 (O5.5I + O6.5-7I, P = 2.1852 days), together with the analyses of its photometric lightcurve and orbital solution. We also present the first results of our analyses of the triple system HD17505 ([O7.5V + O7.5V, P = 8.57 days] + O6.5III). [less ▲]

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See detailPaleoenvironmental implications in the dried lake sediments (Amik Lake, Southern Turkey)
El Ouahabi, Meriam ULg; Hubert, Aurelia ULg; Vander Auwera, Jacqueline ULg et al

Poster (2016, July)

The Amik Basin in the Eastern Mediterranean region has been continuously inhabited since 6000 – 7000 BC. The study focuses on the sedimentary record of the Amik Lake located in the central part of the ... [more ▼]

The Amik Basin in the Eastern Mediterranean region has been continuously inhabited since 6000 – 7000 BC. The study focuses on the sedimentary record of the Amik Lake located in the central part of the basin. Our objective is to constrain major paleo-environmental changes in the area over the last 4000 years and to unravel possible human impacts on the sedimentation. A diverse array of complementary methods was applied on the 6 m long record. Mineralogical (XRD), and geochemical (XRF) analyses were performed. The age of the record is constrained combining radionuclide and radiocarbon dating. A high sedimentation rate of 0.12 cm/yr was inferred at the studied site. The 4000 years (since ~1800 BC) long record shows that significant fluctuations of the lake level and the riverine system inflow into the Amik Lake occurred. The Late Bronze lowstand led to punctual dryings of the lake at the end of the Bronze/Iron Age transition. At that time, the rivers yielded a large terrigenous input linked to strong soil erosion related mainly to deforestation and exploitation of mineral resources. During the Roman and later periods, upland soils were partly depleted and the riverine system completely transformed by channelization (anthropic) that led to a marshification of the Amik Basin [1]. Chemical and mineralogical composition of sediments is quite diversified reflecting the significant geological variation of drainage basins. Periods with strong aggradation linked to major increase in erosion were identified and characterized by high amount of Cr, Ni and Zr. Levels relatively rich in fluorite, richterite, enstatite, hornblende and chrysotile are a result of the erosion of the ophiolitic rocks from the surrounding Amanos Mountains. These levels are interpreted as periods of relatively high physical erosion, while more humid periods led to more intensive weathering. Consequently, the dominance of kaolinite, muscovite/illite and talc indicates a climate with contrasting seasons. During the most recent period a marked increase in terrigenous minerals associated with a rise in dolomite indicates ungoing erosion as well as the drying-out of the lake. [1] T.J. Wilkinson, L. Rayne, Water History, 2, 115-144 (2010). [less ▲]

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See detailChallenge testing with Brochothrix thermosphacta on minced pork meat shows interest to couple metagenetics to metabolomics to study food spoilage
Baré, Ghislain ULg; Cauchie, Emilie ULg; Leenders, Justine ULg et al

Poster (2016, July)

The spoilage of perishable foods is mainly caused by bacterial activity. The risk of unwanted bacterial growth is particularly high in the minced pork meat. In this work, the natural microbial ... [more ▼]

The spoilage of perishable foods is mainly caused by bacterial activity. The risk of unwanted bacterial growth is particularly high in the minced pork meat. In this work, the natural microbial contaminants of the minced pork meat were followed by 16S ribosomal DNA deep sequencing (metagenetics) during aging tests at different temperatures. Brochothrix thermosphacta MM008 strain was selected as one of the main contaminants responsible for the spoilage of the meat. Minced pork meat previously sterilized by gamma irradiation was inoculated with B. thermosphacta MM008 for challenge tests measuring growth and then incubated at different temperatures. Minced meat samples were taken and analyzed by H-NMR 1D at time 0 and at final time (from 14 to 19 days, depending on the incubation temperature). Orthogonal partial least square discriminant analysis (OPLS-DA) showed that samples, regardless of the incubation temperature, could be splitted into 3 groups according to their spectral profile: 1) samples taken at time 0, 2) samples inoculated with B. thermosphacta and taken at final time, 3) samples uninoculated, taken at final time. From the analysis of the metabolomics data, higher concentrations of glycerol, glucose, taurine, lactate, carnitine, betaine and glycine were identified in the samples of uninoculated minced pork meat and an increased production of creatine, acetate and acetone was found in the samples of minced pork meat inoculated with B. thermosphacta MM008. These observations showed that -omics technologies (metagenetics and metabolomics) could be used conclusively to study microbial spoilage of minced pork meat. [less ▲]

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See detailA Frasnian palynological assemblage from the NE Iberian Chain
Rial, Gonzalo; Cascales-Miñana, Borja ULg; Gerrienne, Philippe ULg et al

Poster (2016, July)

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See detailSolo vs. duet in different virtual rooms: On the consistency of singing quality across conditions
Fischinger, Timo; Kreutz, Gunter; Larrouy, Pauline ULg

Poster (2016, July)

Previous research on vocal pitch accuracy revealed insights into the fundamentals of singing. However, most of the research on singing focused on the analysis of single voices, whereas few aYempts have ... [more ▼]

Previous research on vocal pitch accuracy revealed insights into the fundamentals of singing. However, most of the research on singing focused on the analysis of single voices, whereas few aYempts have been made to tackle the challenge of analyzing mulTtrack recordings of singing ensembles. In addiTon, singers have to adjust their way of singing with respect to a given venue’s acousTcal environment (e.g., small room vs. a comparaTvely large space like a church). If it is common that musical performances are greatly influenced by room acousTcs, studies on the effects of room acousTcal features during ensemble singing are rare. In order to invesTgate singing performances across various condiTons, we manipulated the singing condiTon (unison, canon, solo) as well as the acousTcal feedback by applying diverging virtual rooms. Three duets with female singers (N = 6) were asked to sing three different melodies using headset microphones to record each singer separately. Recordings took place in the communicaTon acousTc simulator (CAS) at the House of Hearing (Oldenburg, Germany) to be able to provide different simulated acousTcal spaces (i.e., cathedral, classroom, and dry condiTon) to the singers. ObjecTve measures were performed on each recording and confirmed that the singers sang the melodies with high precision (small pitch interval deviaTons) hardly affected by singing condiTons or by the type of acousTcal feedback. However, the singers tended to driH (larger deviaTons of the tonal center) when singing in canon compared to solo and unison singing. Overall, the analysis of the pitch accuracy showed a general effect of condiTon (i.e., unison, canon, solo), but no general effect of acousTcal feedback and no interacTon between the two variables under study. [less ▲]

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