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See detailValidation par biomarqueurs d’un FFQ permettant d’étudier le lien entre alimentation et risques cardiovasculaires
Sauvageot, Nicolas ULiege; Alkerwi, Alaa; Donneau, Anne-Françoise ULiege et al

Poster (2012, September)

Introduction La recherche sur l'alimentation et son lien avec les maladies nécessite une collecte rigoureuse des données nutritionnelles permettant d'estimer avec précision l'apport nutritionnel. Le « ... [more ▼]

Introduction La recherche sur l'alimentation et son lien avec les maladies nécessite une collecte rigoureuse des données nutritionnelles permettant d'estimer avec précision l'apport nutritionnel. Le « Food Frequency Questionnaire (FFQ) » a été choisie pour étudier le lien entre alimentation et risques cardiovasculaires dans un échantillon représentatif de la Grande région recruté pour l’étude NESCAV (Nutrition, environnement et santé cardio-vasculaire). Objectif Valider le FFQ utilisé à l’aide de biomarqueurs afin d’évaluer son habilité à estimer correctement les habitudes alimentaires. Méthodes Afin de prendre en compte les spécificités de la Grande région et le volet cardio-vasculaire, la liste d’items d’un FFQ existant a été modifiée et élargie. Tous les nutriments calculés à partir du FFQ ont été ajustés par rapport à l’énergie par la méthode des résidus. La comparaison des nutriments calculés par le FFQ et les bio-marqueurs correspondants a été faite par le calcul des coefficients de corrélation avec ajustement sur plusieurs facteurs confondants. L’accord entre les deux méthodes a été estimé par le calcul des pourcentages de concordance et du coefficient Kappa. Résultats La validation s’est effectuée sur un échantillon de 466 sujets (236 hommes et 241 femmes). Des corrélations significatives ont été observées pour les folates, le β-carotène dans les deux sexes et pour la vitamine B12 et l’iode chez les femmes. Discussion Ces résultats sont comparables à ceux d’études précédentes. Les corrélations sont souvent expliquées par le fait que les nutriments du FFQ représentent la quantité ingérée alors que les biomarqueurs représentent la quantité absorbée par le corps. [less ▲]

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See detailThe detection and characterization of broad-leaved forest canopy gaps: a regeneration perspective
Bonnet, Stéphanie ULiege; Bauwens, Sébastien; Lehaire, François ULiege et al

Poster (2012, September)

Canopy gaps are areas of high regeneration potential and, in uneven-aged forest, gaps are therefore places of particular care for the forest manager. Nevertheless the cartography and characterization of ... [more ▼]

Canopy gaps are areas of high regeneration potential and, in uneven-aged forest, gaps are therefore places of particular care for the forest manager. Nevertheless the cartography and characterization of canopy gaps are complex issues. This paper addresses the fundamental question of the canopy gap definition: what is the minimal area, the maximal height of vegetation, type of regeneration, etc? From a regeneration point of view, canopy gaps can be defined as holes in the forest cover where light conditions are suitable for recruitment. As an active sensor, LiDAR has made it possible to tackle the problems of shadows and penetration into the canopy, typical of aerial images. This study investigates the cartography and characterization of forest canopy gaps as areas of natural regeneration. [less ▲]

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See detailPET In Conscious Rodents - Quantification of Stress During The Training Process
Warnock, Geoffrey ULiege; Bahri, Mohamed Ali ULiege; Bretin, Florian ULiege et al

Poster (2012, September)

Recently several methods for performing PET studies in conscious rodents have been developed [1-3]. These methods have the potential to greatly improve the translational nature of PET studies in rodents ... [more ▼]

Recently several methods for performing PET studies in conscious rodents have been developed [1-3]. These methods have the potential to greatly improve the translational nature of PET studies in rodents. One of the most easily implemented methods is the training of a rat to tolerate head fixation in a restraining device. Training consists of intervals of restraint over several days. However, the stress induced by this training procedure has not been quantified in detail. Limited changes in plasma corticosterone have been reported, but this data may be confounded by sample timing and baseline levels. An implantable telemetry system (Telemetry Research) was used to remotely measure blood pressure, heart rate and core temperature during training. Transmitters were implanted in the abdominal cavity under isoflurane anesthesia, with the blood pressure sensor fixed in the abdominal aorta. Training was started after a recovery period of at least 1 week. Training consisted of a 5 min period of acclimatization in the cage containing the restraining device, followed by increasing durations of restraint in the device on subsequent training days (15, 30, 45, 60, 90 min). Telemetry data was acquired from 5 min prior to acclimatization to 60 minutes post-training. In this initial pilot study, a single rat was trained, without head fixation, for 4 consecutive days and again on day 7. All reported values are mean ± SEM across the five training days. In the home cage, prior to acclimatization, baseline heart rate (HR) was 294 ± 15 bpm. During the acclimatization period, HR was elevated to 411 ± 7 bpm. Immediately after starting training, HR was 419 ± 16 bpm. During the training period HR showed a tendency to decrease, with raised periods at undefined intervals. After return to the home cage, HR remained elevated for 15-20 min before returning to a value (313 ± 9 bpm) close to baseline. A similar pattern was seen in blood pressure (mean; BP). Baseline BP was 76 ± 7 mmHg, increasing to 94 ± 9 mmHg during acclimatization. After commencing training, a peak in BP was reached at 102 ± 8 mmHg. After the 15-20 min recovery interval, BP returned to a baseline of 77 ± 9 mmHg. The HR and BP responses to acclimatization and to the training protocol persisted throughout all training days, with the main noticeable difference being the number of bouts of increased HR, which increased with training duration. Core body temperature (baseline: 37.45 ± 0.21 °C) increased during restraint training, with a subsequent post-training peak (38.21 ± 0.03 °C). Measurement of core temp is complicated during longer training sessions by the need to charge the transmitter. This early data indicates that stress induced by the training procedure for conscious PET persists after several days of training. In subsequent studies the head will be fixed and the effect of the training on plasma corticosterone and central glucose metabolism (using [18F]FDG) will be examined. [1] Momosaki et al. (2004) Synapse 54:207–213 [2] Wyss et al. (2009) NeuroImage 48:339–347 [3] Itoh et al. (2009) J Nucl Med 50:749–756 [less ▲]

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See detailSmall animal imaging with human PET
Bahri, Mohamed Ali ULiege; Tombuloglu, S; Warnock, Geoffrey ULiege et al

Poster (2012, September)

PET studies provide valuable information in the assessment of animal models for human diseases. MicroPET systems provide the high resolution needed to explore small organs but suffer from a reduced axial ... [more ▼]

PET studies provide valuable information in the assessment of animal models for human diseases. MicroPET systems provide the high resolution needed to explore small organs but suffer from a reduced axial FOV. Multiple bed positions are then used to obtain whole body scans resulting in increased scan time and incomplete dynamic data. In contrast, human PET systems have larger axial FOV but a lower resolution. In this study, an image-based model of the scanner spatial response function combined with a 3D-OSEM reconstruction algorithm were used to improve spatial resolution of the Siemens ECAT EXACT HR+ PET scanner. A stationary double Gaussian model [1] of the ECAT EXACT HR+ point spread function was derived from 18F point source measurements performed at different radial and axial locations in the scanner FOV. This model was used in a 3D-OSEM reconstruction (3D-OSEM-RM). Sinograms were normalized and attenuation and scatter corrected using the Siemens ECAT tools before reconstruction. Both NEMA NU 2-1994 performance phantoms and NEMA NU4-2008 image quality phantom mimicking small animals were used to evaluate the accuracy of corrections for physical effects and the overall image quality. A 50 min dynamic FDG rat study was conducted on the ECAT HR+ and reconstructed with 3D-OSEM-RM. The images were used to compute the metabolic rate of glucose (MRglu) in multiple brain structures. These images were also visually compared to the static image obtained with a FOCUS 120 microPET immediately after the HR+ dynamic scan. The standard deviations of the two Gaussians used to model the transaxial (axial) resolution in a central FOV of 5 cm radius were σ1 = 1.6 (2.75) mm and σ2 = 3.66 (4.16) mm, and the ratio of the weights between the first and second Gaussians was ρ = 0.2 (0.7). Image uniformity and accuracy of scatter and attenuation corrections, evaluated following NEMA NU 2-1994, were found to be very similar between 3D-OSEM, 3D-OSEM-RM, 2D- and 3D-FBP reconstructed images. When using the NEMA NU4-2008 image quality phantom a significant increase of the hot rod recovery coefficient was observed. This effect was rod size dependent and amounted to 17-35% for the 3D-OSEM-RM compared to the 3D-OSEM and to 35-62% compared to the FBP reconstructions. Nevertheless the values obtained with 3D-OSEM-RM were around 20-35% lower than those obtained with the FOCUS 120 microPET scanner. Most of the small brain structures observed on microPET images were also visible on the images obtained with the HR+ scanner and 3D-OSEM-RM. Rat cerebral MRglu values calculated on 3D-OSEM-RM images were in the range of published values [2] (e.g. whole brain = 25.34 μmol/min/100g). Using an approximate model of the ECAT EXACT HR+ spatial response in 3D-OSEM resulted in sufficient image quality for dynamic whole body scans of small rodents, despite the large FOV, and resulted in improved contrast compared to images generated using the built-in software. This methodology will be applied for future small animal dosimetry and modeling studies in our laboratory. [1] Comtat et al. IEEE Nucl Sci Symp Conf Record. pp. 4120-4123 (2008) [2] Schiffer et al. J Nucl Med 48:277-287 (2007) [less ▲]

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See detailAcute burn care : state of the art in Europe
ROUSSEAU, Anne-Françoise ULiege; LEDOUX, Didier ULiege; MASSION, Paul ULiege et al

Poster (2012, September)

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See detailDosimetry for 6-[18F]Fluoro-L-DOPA in humans based on in vivo microPET scans and ex vivo tissue distribution in mice
Bretin, Florian ULiege; Warnock, Geoffrey ULiege; Bahri, Mohamed Ali ULiege et al

Poster (2012, September)

Radiation dosimetry of new radiopharmaceuticals generally starts with studies in small animals such as mice and rats. The traditional technique has long been ex vivo measurement of the biodistribution ... [more ▼]

Radiation dosimetry of new radiopharmaceuticals generally starts with studies in small animals such as mice and rats. The traditional technique has long been ex vivo measurement of the biodistribution over time using harvested organs at different times post administration of the radiopharmaceutical. Since this approach requires a significant amount of animals, dynamic microPET studies, where the biodistribution of the tracer over time can be determined in vivo in a single scan, are an invaluable alternative. Due to known imaging artifacts and limitations, such as partial volume effect, a hybrid technique combining harvesting organs (post-scan) and dynamic imaging was introduced to achieve a cross-calibration to account for these limitations. Since 6-[18F]Fluoro-L-DOPA is a widely used PET tracer to study the dopaminergic system in neurology and oncology and there is no sound published dosimetry data, absorbed doses for major organs in humans were estimated using the traditional ex vivo technique and by dynamic microPET imaging in mice, allowing direct comparison of the results from the two techniques. The tissue distribution over time of 6-[18F]Fluoro-L-DOPA was determined by radioassay of harvested organs at 2, 5, 10, 30, 60, 120 minutes post administration (n=5 at each time point) in isoflurane-anaesthetized mice. Dynamic PET images were acquired with a FOCUS 120 microPET for 120 minutes after injection of 6-[18F]Fluoro-L-DOPA followed by radioassay of harvested organs (n=4). A bladder voiding scenario was used to simulate excretion every 2 h. The organ time-activity-curves (TACs) from both methods were extrapolated from a simulated 35 g standard mouse to a 70 kg standard male human using a technique based on organ to bodyweight ratios. The absorbed doses in major human organs were calculated with the commercially available human dosimetry software OLINDA/EXM (Version 1.1) using the extrapolated TACs. The extrapolated organ TACs obtained using the two methods showed a high correlation (average r = 0.94 ± 0.05, p < 0.001). However, TACs from PET alone under- or overestimated the activity in individual organs in contrast to TACs obtained using the cross-calibration of the PET data with the activity in post-scan dissected organs. Those organs in the excretion pathways, comprising bladder wall, kidneys and liver, received the highest organ doses. The total body absorbed dose was 0.0118 mGy/MBq for both the imaging based and harvesting based methods. The effective dose was 0.0193 mSv/MBq for the hybrid imaging-harvesting technique and 0.0189 mSv/MBq for the pure harvesting technique. Scaling errors in the PET TACs are likely caused by quantification errors such as partial volume effects and image artifacts. The use of a hybrid imaging technique to cross-calibrate the TACs improved the accuracy of the imaging-based dosimetry estimates. Therefore the hybrid technique combining dynamic imaging and harvesting organs (post-scan) is a suitable alternative to the gold standard ex vivo radioassay method. It yields comparable results yet reduces significantly the amount of animals needed in the study and can accelerate data acquisition. [less ▲]

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See detailMicroPET Focus 120 scanner use at high-­‐count rate
Bahri, Mohamed Ali ULiege; Warnock, Geoffrey ULiege; Taleb, Dounia ULiege et al

Poster (2012, September)

Kinetic modeling of physiological processes using imaging techniques requires an accurate measurement of the time-activity curve of the tracer in plasma, known as the arterial input function (IF). The IF ... [more ▼]

Kinetic modeling of physiological processes using imaging techniques requires an accurate measurement of the time-activity curve of the tracer in plasma, known as the arterial input function (IF). The IF can be obtained by manual blood sampling, can be derived from PET images, or continuously measured by the use of small counting systems such as beta microprobes [1]. However, some beta microprobe systems can suffering from high background counts and low sensitivity compared to PET can obligate the use of activities higher than those typical for the imaging system. In the present study, the NEMA NU4-2008 image quality (IQ) phantom [2] was used to evaluate the image quality of the microPET Focus 120 at high activity values. Attenuation correction was obtained from transmission measurement using 57Co point source. Eight emission scans of 20 minutes were performed at decreasing activity starting from 109 MBq to 3.7 MBq (total activity in the field-of-view). To study the effect of normalization in high count rate studies, several normalization scans were performed using activities ranging between 18 and 212 MBq. Images were reconstructed with all corrections using Fourier rebinning and filtered backprojection. The mean activity and the coefficients of variation of the uniform slices were measured. All high activity reconstructed images showed a detector-block-patterned artifact with an overestimation of the counts when normalization activity is higher than that used in the IQ phantom and underestimation of the counts when normalization activity is below the activity used in the IQ phantom. Using the same high activity for acquisition and normalization considerably reduces the patterned-artifact but does not eliminate it entirely. The observed artifact is due to pulse pile-up in the detectors at high count-rates. A dedicated rejection of the pulse pile-up does not appear to have been implemented for the microPET Focus 120. An alternative would be to re-calibrate the detectors with higher activity values to prevent any pile-up effect or to create an attenuation volume into which phantoms or small animals could be inserted thus decreasing the artifact. This latter option is under development. References: [1] G. Warnock et al, European Journal of Nuclear Medicine and Molecular Imaging Research, 1-13 (2011) [2] NEMA Standards Publication NU4-2008. Rosslyn, VA: National Electrical Manufacturers Association; (2008). [less ▲]

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See detailEvaluation des modèles climatiques régionaux MAR et WRF sur le Svalbard
Lang, Charlotte ULiege; Fettweis, Xavier ULiege; Erpicum, Michel ULiege

Poster (2012, September)

: Il est bien connu que les zones de hautes latitudes sont très sensibles aux changements climatiques. A cause du réchauffement global, la fonte des calottes a augmenté, ce qui à son tour a une influence ... [more ▼]

: Il est bien connu que les zones de hautes latitudes sont très sensibles aux changements climatiques. A cause du réchauffement global, la fonte des calottes a augmenté, ce qui à son tour a une influence sur le climat via des modifications de la circulation thermohaline, la rétroaction de l’albédo de la glace, l’augmentation du niveau des mers… Nous avons comparé le climat du Svalbard modélisé par deux modèles régionaux (MAR et WRF) à une résolution de 10 km sur la période 2000-2010 à des mesures provenant de plusieurs stations météorologiques localisées dans différentes régions de l’archipel afin d'évaluer lequel de ces modèles pouvait représenter au mieux le climat du Svalbard. [less ▲]

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See detailLinguistic identity, language attitudes and language perception in the German-speaking community of Belgium: A comparative study across the German-Belgian border.
Weber, Sandra ULiege

Poster (2012, September)

If you have a look on the media in the German-speaking Community of Belgium (GC), you will find how prevalent the subject of language is in the minds of the German-speaking Belgians. East Belgian ... [more ▼]

If you have a look on the media in the German-speaking Community of Belgium (GC), you will find how prevalent the subject of language is in the minds of the German-speaking Belgians. East Belgian linguistic characteristics are frequently treated in the media (cf. e.g. the radio competition “Ostbelgien lernt Deutsch – der germanistische Adventskalender“) and just recently, a popular scientific dictionary of East Belgian everyday language has been published. This suggests that in the GC, there is a feeling that German as it is spoken in East Belgium differs from German spoken in the Federal Republic of Germany. This project asks the question of how East Belgian linguistic characteristics in everyday language are perceived and judged by the German-speaking Belgians, and to what extent they are part of their linguistic identity. Special attention is paid to the question of how far linguistic identity, language attitudes and language perception in the GC are influenced by the political and cultural situation of the region. The German-speaking Community is a partly independent political entity within the Belgian federal system. The eventful history of the region (3 changes in nationality within 25 years) and the minority situation have made it difficult for the inhabitants of the GC to find their own identity and a sense of “we-ness”. The inhabitants of the GC speak a language whose “mother country” is neighbouring Germany and they are closely linked to German culture through the media – nevertheless, they do not feel German. At the same time, within the state of Belgium, they are a linguistic minority, but they are also linked to Belgian culture through intensive contacts. Within Belgium, the German-speaking Belgians can use the German language to claim uniqueness (cf. the term “German-speaking Community”), but this does not work on the international level. But can dissociation from the German citizens happen on a linguistic level nevertheless, through regional variants and varieties? Since there are basically great similarities between the linguistic situation in the GC and in the bordering German areas (both on the level of the traditional dialects and regional linguistic features as well was in the vertical structure of variety use), while the extra-linguistic situations are very different, a comparative survey across the Belgian-German border is especially enlightening. The most important questions I want to raise are thus: How strong is the feeling that the regional everyday speech differs from that spoken on the other side of the national border? To which degree do these beliefs correspond to reality? What is in the eyes of the local population on both sides of the frontier typical of this variety? How do they evaluate it? And which functions do occurring regional features of German have for the identity of the people on both sides of the frontier? The methodology and first results have been presented on the poster. [less ▲]

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See detailUNFOLDING SYNTHETIC PEPTIDES BY AFM AT THE SINGLE-MOLECULE LEVEL
Willet, Nicolas ULiege; Hinterdorfer, Peter; Lecommandoux, Sébastien et al

Poster (2012, September)

The aim of this study is to investigate the mechanochemical behavior of homopolypeptides able to change their conformation is a stimuli-responsive way. The peptidic secondary structures were studied in ... [more ▼]

The aim of this study is to investigate the mechanochemical behavior of homopolypeptides able to change their conformation is a stimuli-responsive way. The peptidic secondary structures were studied in detail by atomic force microscopy (AFM) at the single-molecule level. Synthetic copolymers containing a polypeptide block were prepared by N-carboxyanhydride amino acid ring-opening polymerization. The polymer chains were grafted as a dilute brush onto gold surfaces and their mechanochemical behavior was then studied by AFM single-molecule force spectroscopy (SMFS). The investigated polypeptide blocks were based on poly(L-glutamic acid), which undergoes a transition from alpha-helix to random coil. This can be induced by external stimuli (pH, ionic strength, temperature) or simply by applying a force. We were able to study the mechanically driven unfolding of the peptide by stretching-release cycles of the biomacromolecule. Stretching the helical peptide resulted in original features in the force-distance traces. Plateaus that are specific for the helical conformation were detected, quantified and discussed. Pulling-relaxing SMFS experiments will eventually lead to a better understanding of the force-induced unfolding of an alpha-helix and the reversibility of the phenomenon. [less ▲]

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See detailChange in naming abilities between the ages of 50 and 90: The importance of analyzing naming latency
Verhaegen, Clémence ULiege; Poncelet, Martine ULiege

Poster (2012, September)

Introduction This study tests the controversial hypothesis that word naming difficulties may arise in individuals as young as their 50s. According to Feyereisen (1997), these difficulties begin at the age ... [more ▼]

Introduction This study tests the controversial hypothesis that word naming difficulties may arise in individuals as young as their 50s. According to Feyereisen (1997), these difficulties begin at the age of 70, but Nicholas, Connor, Obler, and Albert (1998); Connor, Spiro, Obler, and Albert (2004) observed subtle signs of decreased naming performance in participants in their 50s. However, these studies focused on naming accuracy. To our knowledge, no study has analyzed naming latencies in participants in their 50s in comparison with younger participants. We assume that such analyses may highlight more subtle difficulties in naming. In our study, both naming latencies and naming accuracy were analyzed in a picture naming task presented to 4 age groups: 25-35, 50-59, 60-69 and above 70 years old. If people in their 50s experience subtle naming difficulties, these should be reflected in longer picture naming latencies compared to younger participants. In participants above 70 years of age, the decline should be more apparent and may be underlined not only by slower naming latencies but also by lower picture naming scores. The explanation for naming difficulties in aging is also a matter of debate. According to some authors (e.g., Salthouse, 1996), these difficulties are a consequence of a general slowing in all cognitive tasks, including language, in the elderly. However, other theories suggest that the relevant difficulties are more language-specific and are due to connection weaknesses across the entire language system, leading to more naming errors and longer naming latencies (e.g., Burke, MacKay, Worthley, & Wade, 1991). In order to determine the extent to which the slowing of naming latencies in the elderly is related to a slowing of cognitive processing, participants’ cognitive processing speed was assessed with an odd/even judgment task. We were also interested in seeing whether slowing on the odd/even judgment task arises at the same age than slowing on the picture naming task. Methods Participants Four groups of 30 participants took part in the present study: (1) between 25 and 35 years of age, (2) between 50 and 59 years of age, (3) between 60 and 69 years of age and (4) above 70 years of age (70+). All subjects were native French speakers and reported no history of neurological, cardiac, neuropsychological or psychiatric disorders, and no uncorrected hearing or visual problems. Dementia was excluded with the Mattis Dementia Rating Scale (Schmidt, Freidl, Fasekas, Reinhart, & Grieshofer, 1994). No differences between groups were found for vocabulary level (Mill Hill test; Deltour, 1993) or socio-economic background. Materials Participants performed a picture naming task (150 black and white drawings selected from the set of Bonin, Peereman, Maladier, Méot, and Chalard, 2003). Both the number of correct responses and naming latencies were analyzed. We also analyzed response latencies on an odd/even judgment task on 50 digits from 1 to 9, to assess cognitive processing speed. Results For the picture naming task, an analysis of variance (ANOVA) performed on the number of correctly named items revealed an effect of age, F(3,116)=35.36, p<.001. Tukey post hoc comparisons (p<.05) indicated that the 70+ age group named fewer items correctly than the 60-69 age group, which performed worse than the 25-35 and 50-59 age groups, which in turn did not differ from each other. However, the ANOVA performed on correct naming latencies did not show the same pattern of results. This analysis revealed an effect of age, F(3,116)=35.36, p<.001. Tukey post hoc comparisons (p<.05) indicated that the 25-35 age group responded faster than the 50-59 and 60-69 age groups, which did not differ from each other. The 70+ age group responded more slowly than the 3 younger groups. For the odd/even judgment task, the ANOVA performed on response latencies indicated an effect of age, F(3,116)= 96.40, p<.001. Tukey post hoc comparisons (p<.05) showed that the 25-35 and 50-59 age groups did not differ from each other and responded faster than the 60-69 and 70+ age groups, which in turn did not differ from each other. An analysis of covariance was also performed on naming latencies, using the latencies on the odd/even judgment task as covariate. There was a significant effect of age, F(4,115)=54.56, p<.001. Tukey post hoc analysis indicated that the 25-35 age group responded faster than the 50-59 and 60-69 age groups, which did not differ from each other. The 70+ age group performed more slowly than the 3 younger groups. Thus, a slowing of picture naming latencies was found in participants above 50 years of age. This slowing remained significant even when cognitive processing speed was controlled for. Discussion The increase in correct naming latencies on the picture naming task in participants in their 50s suggests the presence of subtle age-related word finding difficulties. In participants in their 60s, naming difficulties were highlighted by both a decrease in correct responses and an increase in naming latencies. Finally, in participants above 70 years of age, these difficulties became more pronounced in both naming accuracy and naming latencies. Slowing on the picture naming task appears to be greater and to arise earlier in the adult lifespan (in participants in their 50s) than slowing on the odd-even judgment task assessing processing speed (in participants in their 60s). Moreover, this slowing of picture naming latencies in participants in their 50s remained significant even when processing speed was controlled for with an analysis of covariance. In conclusion, these results support the importance of naming latency analyses in uncovering subtle naming difficulties. Furthermore, although we do not exclude a possible impact of general slowing on naming latencies in participants above 50 years of age, these findings suggest that the slowing in naming at this age observed here may be explained by a specific age-related slowing within the language system. References Bonin, P., Peereman, R., Maladier, N., Méot, A., & Chalard, M. (2003). A new set of 299 pictures for psycholinguistic studies: French norms for name agreement, image agreement, conceptual familiarity, visual complexity, image variability, age of acquisition, and naming latencies. Behavior Research Methods, Instruments, & Computers, 35(1), 158-167. Burke, D. M., MacKay, D. G., Worthley, J. S., & Wade, E. (1991). On the tip of the tongue: what causes word finding failures in young and older adults? Journal of Memory and Language, 30(1), 542-579. Connor, L.T., Spiro, A., Obler, L. K., & Albert, M. L. (2004). Change in object naming ability during adulthood. The Journals of Gerontology: Series B, 59(5), 203-209. Deltour, J. J. (1993). Echelle de vocabulaire Mill Hill de J.C. Raven. Braine-le-Chateau, Belgium: Editions l’Application des Techniques Modernes. Feyereisen, P. (1997). A meta-analytic procedure shows an age-related decline in picture naming: Comments on Goulet, Ska et Kahn (1994). Journal of Speech, Language, and Hearing Research, 40(1), 1328-1333. Nicholas, M., Connor, L.T., Obler, L. K., & Albert, M. L. (1998). Aging, Language, and Language Disorders. In M. Taylor Sarno (Ed.), Acquired Aphasia (pp. 413-449). San Diego, CA: Academic Press. Salthouse, T. A. (1996). The processing-speed theory of adult age differences in cognition. Psychological Review, 103(3), 403-428. Schmidt, R., Freidl, W., Fasekas, F., Reinhart, B., & Grieshofer, P. (1994). Mattis Dementia Rating Scale. [less ▲]

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See detailA confocal microscopic study of mitochondrial alterations of renal HK-2 cells exposed to an endotoxic stress
Quoilin, Caroline ULiege; Mouithys-Mickalad, Ange ULiege; Fontaine-Aupart, Marie-Pierre et al

Poster (2012, September)

Sepsis has a profound deleterious effect on kidney functions through complex mechanisms, which involve the immune response, inflammatory pathways, intracellular dysfunction and hemodynamic instability ... [more ▼]

Sepsis has a profound deleterious effect on kidney functions through complex mechanisms, which involve the immune response, inflammatory pathways, intracellular dysfunction and hemodynamic instability. Those factors are difficult to discriminate in vivo. To get a better understanding of renal respiratory dysfunction, we developed an in vitro model of sepsis-induced acute kidney injury using proximal tubular epithelial cell lines (HK-2) exposed to a bacterial endotoxin (lipopolysaccharide, LPS). Using this model, our first work has demonstrated that the basal respiration of renal HK-2 cells subjected to endotoxins was altered and presented a strong decrease in the oxygen consumption rates. Our working hypothesis of the pathophysiology of sepsis-induced AKI is based on a change in mitochondrial function that has been termed cytopathic hypoxia. A consequence of mitochondrial function alterations is an inability of the cell to use molecular oxygen for ATP production. The oxidative phosphorylation within mitochondria is interrupted because of the inhibition of cytochrome oxidase. The present investigation was carried out to establish whether mitochondrial alterations might be a mechanism of renal tubular epithelial injury during sepsis. To reach this goal the mitochondrial alterations of renal HK-2 cells exposed to an endotoxic stress was studied by confocal laser-scanning microscope. Confocal microscope allowed observation of the evoked phenomena at the single cell level and in real time. More particulary, mitochondrial morphology, mitochondrial membrane potential (ΔΨm) and generation of reactive oxygen species were recorded using specific vital fluorescent probes and quantified by image processing and analysis. Mitochondrial membrane potential is generated by the mitochondrial electron transport chain. This gradient is critical for the formation of ATP, and a fall in membrane potential is an indicator of mitochondrial dysfunction. ΔΨm was measured using the lipophilic cationic probe TMRE and it was shown that LPS produced a decrease in ΔΨm. In parallel, superoxide generation was measured by using MitoSOX which is selectively targeted to the mitochondria. There was a significant increase in mitochondrial superoxide-specific oxidation of MitoSOX when HK-2 cells were submitted to LPS. Overall, the model of HK-2 cells exposed to LPS displays some key features of sepsis-induced acute kidney injury. The confocal microscopy study has suggested a mechanism of toxicity dependent on mitochondrial oxidant generation and mitochondrial dysfunction. Indeed, the exposure to LPS has resulted in an increased generation of superoxide and a loss of mitochondrial function probably initiated by a fall in mitochondrial potential. [less ▲]

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See detailEsthétique des os : la dimension réflexive des radiographies érotiques
Sturnack, Lionel ULiege

Poster (2012, September)

L’analyse portera sur une œuvre de l’artiste italienne Benedetta Bonichi, titrée Striptease. Il s’agit d’une réalisation à mi-chemin entre les procédés de la photographie et ceux du rayon-x, présentant un ... [more ▼]

L’analyse portera sur une œuvre de l’artiste italienne Benedetta Bonichi, titrée Striptease. Il s’agit d’une réalisation à mi-chemin entre les procédés de la photographie et ceux du rayon-x, présentant un modèle féminin dans une pose érotique. L’objectif de la présentation sera d’exposer le discours réflexif qui se développe dans Striptease, grâce à la décomposition de sa complexité énonciative et figurative. L’œuvre sera envisagée à l’intérieur d’un ensemble de productions artistiques issues des procédés de la radiographie. En première instance, nous procéderons à une description de l’œuvre sous l’aspect des formants plastiques qui la composent et de leur organisation particulière. Cette première partie, brève, sera menée en accord avec les propositions de Jean-Marie Floch dans Petites mythologies de l’œil et de l’esprit et dans Formes de l’empreinte. Elle permettra d’obtenir une base descriptive stable au sein de laquelle d’autres radiographies artistiques pourront être envisagées. Ainsi, six œuvres d’artistes de différents horizons, dont celle de Benedetta Bonichi, seront abordées afin d’exposer différents types de variations repérables sur la base de la description plastique effectuée précédemment. Sous ces préalables, il sera possible de catégoriser quelques variations remarquables dans un ensemble d’œuvres homogène du point de vue de ses procédés énonciatifs. Enfin seront approfondies plus longuement les relations notables entre trois niveaux thématiques, tels qu’ils ont été définis par François Rastier dans Systématique des isotopies, où l’auteur propose une lecture sémantique faisant se croiser trois thèmes (pratique, mythique et métalinguistique) qui structurent un texte. Ces relations, également observables dans les travaux mis en analyse, permettront de systématiser leur approche, en soulignant les tensions particulières qui s’y tissent. Aussi, dans cette dernière approche, l’étude se focalisera sur trois œuvres partageant à la fois les mêmes procédés énonciatifs issus de la radiographie, et à la fois le même thème figuratif ou mythique. En l’occurrence, l’érotisme sera interrogé dans son dialogue avec les procédés du rayon-x dans trois compositions, de Benedetta Bonichi, de Wim Delvoye et de l’agence publicitaire Butter. Différents aspects de ce dialogue thématique seront développés, avec un accent particulier sur la complexité du travail de la photographe italienne, dont la portée réflexive questionne le domaine du visuel, notamment sous l’aspect de l’outillage scientifique qui s’y inscrit. [less ▲]

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See detailCharacterisation of a scroll expander for small scale absorption power and cooling cycle activated by solar energy or waste heat
Mendoza, Luis Carlos; Navarro, Joaquin; Lemort, Vincent ULiege et al

Poster (2012, September)

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See detailMolecular epidemiology of norovirus in symptomatic and asymptomatic population in Burkina Faso
HUYNEN, Pascale ULiege; Mauroy, Axel ULiege; Martin, Caroline et al

Poster (2012, September)

Background Noroviruses (NoV), belonging to the family Caliciviridae, are now recognized as the leading cause of gastroenteritis outbreaks worldwide, and represent an important cause of sporadic ... [more ▼]

Background Noroviruses (NoV), belonging to the family Caliciviridae, are now recognized as the leading cause of gastroenteritis outbreaks worldwide, and represent an important cause of sporadic gastroenteritis in both children and adults. Many studies describe NoV epidemiology. However, few data are available about the NoV strains circulating in most of African countries, in particular in Burkina Faso. The population of Burkina Faso is characterized by the young age of its habitants, and most are living in rural environment. Objectives The purpose of this epidemiological study was to determine the prevalence of NoV in Bobo Dioulasso (Southern part of Burkina Faso) by molecular diagnosis methods in patients presenting or not gastroenteritis symptoms, to quantify the excreted viral load, and to genotype the circulating strains. Methods Patients with and without gastro-intestinal disorders were selected in several Health Care Centres of Bobo Dioulasso. Clinical and epidemiological data, as well as stool samples, were collected during 8 weeks through March to April 2011. Viral genomic RNA was automatically extracted with a Maxwell® (Promega) instrument. Molecular detection of genogroups (G) I, II and IV NoV in stool samples was performed by a home-made real-time RT-PCR targeting the ORF1-ORF2 polymerase junction region. For each positive sample, viral load was estimated by using standard curves (successive dilutions of recombinant GI and GII plasmids). Molecular characterization was performed on the detected strains, using both polymerase and capsid regions. Results NoV were detected in 21.6% of the 453 collected stool samples, with a distribution of 21.0% and 23.1% in the samples from the 319 symptomatic (SP) and the 134 asymptomatic patients (AP) respectively. Genogroup distribution was 7.2% for GI, 10.7% for GII and 3.1% for both GI and GII among SP’s samples, and was 11.2% for GI, 10.4% for GII and 1.5% for both GI and GII among AP’s samples. Average viral load values were higher for GI NoV in SP than in AP (p=0.02), when they were higher for GII NoV in AP than in SP (p=0.04). Phylogenic analysis showed a high degree of genotypical diversity in both groups of patients. One recombinant strain GII.7/GII.6 was also detected, to our knowledge, for the first time. Conclusion Even if a true pathogenic role of NoV could not be showed from the study design, it allowed to precise the molecular epidemiology of NoV strains prevalent in a representative country of the East African region. It also showed that asymptomatic patients could play an important role as a NoV “reservoir”. Despite the fact that GII strains, and more precisely those belonging to GII.4 genotype, are nowadays highly reported worldwide, the surprising proportion of NoV GI detected in this study suggests that GI and GII strains should be excreted in equal proportion in the environment. The origin of this epidemiologic difference, even if partially explained by the difference in immunity and genetic sensitivity of the population, is still to be solved. [less ▲]

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See detailLa perception de la pénibilité au travail dans les métiers du social
Dubois, Valérie ULiege; Cornet, Annie ULiege

Poster (2012, September)

Cet article vise à mettre en évidence les sources de pénibilité au travail telles qu’elles sont perçues par les membres d’une organisation du secteur non-marchand qui travaillent avec des femmes victimes ... [more ▼]

Cet article vise à mettre en évidence les sources de pénibilité au travail telles qu’elles sont perçues par les membres d’une organisation du secteur non-marchand qui travaillent avec des femmes victimes de violence conjugale. Il s’agit de comprendre leurs représentations de la pénibilité du travail, ses effets sur leur santé et bien-être et les politiques de GRH qui pourraient être mises en place pour réduire cette pénibilité. L’originalité de notre communication réside dans le secteur étudié. La thématique de la pénibilité a surtout été étudiée dans des secteurs majoritairement masculins comme la construction et l’industrie. S’il existe quelques travaux sur le secteur de la santé, il existe peu de travaux sur la pénibilité des emplois, majoritairement féminins, du secteur associatif. Cette communication est basée sur des interviews qualitatives réalisées avec les différentes catégories du personnel. Elle répondait à une demande du conseil d’administration qui envisageait de mettre en place une politique de réduction du temps de travail en lien avec l’ancienneté et l’âge sur base de la pénibilité des tâches et qui voulait tester la pertinence d’une telle décision auprès du personnel. L’étude montre que la pénibilité ressentie n’est pas seulement liée à l’âge et à l’ancienneté mais également à des contraintes individuelles (comme la situation familiale) et organisationnelles, notamment les contraintes psychologiques liées au travail avec des personnes ayant vécu un traumatisme. L’étude montre l’importance des politiques de GRH et des styles de management. Donner de l’autonomie au travailleur et des opportunités de développer de nouveaux projets est perçu par tous comme un facteur permettant de réduire la pénibilité. Tous réclament, par contre, une meilleure communication et information sur les tâches et rôles de chacun et plus de synergie entre les équipes. [less ▲]

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See detailCHARACTERIZATION OF A NOVEL RADIOTRACER TARGETING SYNAPTIC VESICLE PROTEIN 2A (SV2A)
Warnock, Geoffrey ULiege; Aerts, Joël ULiege; Bahri, Mohamed Ali ULiege et al

Poster (2012, September)

Synaptic vesicle protein 2A (SV2A) has been identified as the binding site of the antiepileptic levetiracetam (Keppra) [1]. SV2 proteins are critical for proper nervous system function and have been ... [more ▼]

Synaptic vesicle protein 2A (SV2A) has been identified as the binding site of the antiepileptic levetiracetam (Keppra) [1]. SV2 proteins are critical for proper nervous system function and have been demonstrated to be involved in vesicle trafficking. Their implication in epilepsy makes them an interesting therapeutic target, and the widespread distribution of SV2A in particular may provide an opportunity to develop a PET-based measure of neuronal function in brain diseases. [18F]UCB-H is a fluorine-18 radiolabelled PET imaging agent with a nanomolar affinity for the human SV2A protein. Preclinical PET studies in rodents were carried out using male SD rats, imaged under isoflurane anaesthesia in a Siemens Concorde Focus 120 microPET scanner. Arterial input function was measured using an arteriovenous shunt method and beta microprobe system. [18F]UCB-H was injected IV (3.8 ± 0.54 mCi bolus, specific activity 8.5 ± 0.86 Ci/Emol immediately after synthesis) and dynamic PET data acquired in list mode for 90 min. Images were reconstructed using filtered back projection with correction for all physical effects except scatter. These scans revealed high uptake of [18F]UCB-H in brain and spinal cord, matching the expected homogeneous distribution of SV2A in the rodent brain [2]. Notably, the kinetics of [18F]UCB-H uptake in the brain were fast, peaking at up to 30 % ID/cm3 before a rapid decline. Metabolism of [18F]UCB-H in vivo followed a typical pattern of rapid initial metabolism followed by a reducing rate of metabolism over time, with less than 20% of the activity in plasma attributable to the parent compound after 30 minutes, and was highly reproducible between subjects. One major metabolite was identified. The uptake of [18F]UCB-H in the brain over time was well fitted by a classical 1-tissue compartment model. Mean parameter estimates (mean ± SD, n=7, whole brain VOI) were K1: 3.58 ± 0.65 ml/cm3/min, k2: 0.21 ± 0.03 min-1, Vt: 17.21 ± 2.52 ml/cm3. Uptake of [18F]UCB-H was blocked by pretreatment with brivaracetam (21 mg/kg IV, 10 min prior to [18F]UCB-H), a recently described high affinity SV2A ligand with a 20-fold higher affinity for SV2A than levetiracetam [3]. In contrast, pretreatment with ucb-100230-1, a diastereoisomer of brivaracetam with 3200-fold lower affinity for SV2A [3], had no clear effect of the brain uptake of [18F]UCB-H. Our results indicate that [18F]UCB-H is a suitable radiotracer for the quantification of SV2A proteins in vivo and for estimating target occupancy of drugs targeting SV2A. This is the first PET tracer for in vivo quantification of SV2A. The necessary steps for implementation of [18F]UCB-H production under GMP conditions have been completed and first in human studies are planned. References [1] Lynch, B.A. et al. (2004) PNAS 101(26):9861-6. [2] Janz, R. & Sudhof, T.C. (1999) Neuroscience 94(4):1279-1290.[3] Gillard, M. et al. (2011) Eur J Pharmacol 664:36-44. [less ▲]

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See detailPhenotypical and Genotypical Surveillance of Macrolide and Lincosamide Resistance in Group B Streptococcus in Belgium
DESCY, Julie ULiege; Ackermans, Yannick; BOREUX, Raphaël ULiege et al

Poster (2012, September)

Background: Constant increase of erythromycin (E) and clindamycin (C) resistance (R) has been observed worldwide among isolates of group B streptococci (GBS). In Belgium, through the 2000s, E R increased ... [more ▼]

Background: Constant increase of erythromycin (E) and clindamycin (C) resistance (R) has been observed worldwide among isolates of group B streptococci (GBS). In Belgium, through the 2000s, E R increased rapidly from 10% to up to 30%. Therefore phenotypical and molecular surveillance of E and C R has to be conducted. Methods: 275 clinical isolates (N1) were obtained from a Belgian surveillance for invasive GBS disease in newborns (59 isolates with 32 early- and 27 late-onset diseases) and adults (216 strains) during 2008 to 2011 and 53 isolates (N2) from vagino-rectal colonization in pregnant women in 2010. E and C MICs were determined by using Etest® (EUCAST interpretive criteria). Furthermore, for the E R isolates, the inducible (iMLS), constitutive (cMLS) and M phenotypes were assessed by a double disk diffusion test; the distribution of genes encoding RNA methylases and efflux pumps was investigated by PCR. Results: Of the N1 and N2 isolates, 92 (33.5%) and 15 (28.3%) were respectively R to E, with a higher rate among serotype V (p <0.001) and serotype IV (p <0.05). Among these 107 E-R isolates, 100 (93.5%) exhibited the MLS phenotype (R to E and CC): 73 were cMLS with E MIC50 >256 mg/L and 27 iMLS with E MIC50/MIC90 12/>256 mg/L. The M phenotype (R to E and S to C) was expressed by 7 (6.5%) of E R isolates with E MIC50/MIC90 4/12 mg/L. One colonizing strain presented a newly described resistance mechanism in GBS: the L phenotype (S to E and R to C) with a C MIC at 8 mg/L. For cMLS, the most common E R genotype was ermB (66%) (p <0.05) followed by ermTR (29%) and ermB+ermTR (5%). All iMLS isolates harbored an ermTR gene except 3 (2 with ermB, 1 with both ermB and ermTR); and all M phenotype were positive for mefA/B gene. Conclusions:1) In Belgium, by year 2010, prevalence of macrolides R in GBS exceeded 30%, 2) MLS R phenotypes (target-site modification) were the majority mechanism; M phenotype (efflux R mechanism) was also prevalent. 3) E and C susceptibility testing and surveillance are mandatory to guide prophylaxis and treatment of serious GBS infections in penicillin-allergic patients (at high risk for anaphylaxis) but also to identify emergence of newly acquired resistance mechanisms such as the L phenotype. [less ▲]

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See detailDiagnosing structure and composition typologies in uneven-aged broad-leaved forests: a comparison of classification methods
Bonnet, Stéphanie ULiege; Brostaux, Yves ULiege; Claessens, Hugues ULiege et al

Poster (2012, September)

Structure and composition of forest stands are crucial factors for forest planning and biodiversity management. In Belgium, typologies of structure and composition exist to support planning in uneven-aged ... [more ▼]

Structure and composition of forest stands are crucial factors for forest planning and biodiversity management. In Belgium, typologies of structure and composition exist to support planning in uneven-aged broadleaved forests (typically dominated by oak and beech). The principle of these typologies is to classify irregular stands with the percentage of small, medium, large, and very large trees (regarding dbh), and the percentage of basal area of oak and beech. This paper investigates the potential of LiDAR data processed with classification methods (k-nn, K-Means, CART, etc.) to allocate a forest structure and composition type. For this purpose several supervised and unsupervised classification methods are compared, as well as the impact of leaf-on (summer) and leaf-off (winter) data to discriminate the forest types. [less ▲]

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See detailMolecular detection of HAV by a new one step real time RT-PCR
Zonta, William ULiege; Denayer, Sarah; Thiry, Etienne ULiege et al

Poster (2012, September)

Introduction and objectives Hepatitis A virus (HAV) is a RNA virus with a single-stranded positive sense genome and the only species of the genus Hepatovirus of the Picornaviridae family. Belgium and ... [more ▼]

Introduction and objectives Hepatitis A virus (HAV) is a RNA virus with a single-stranded positive sense genome and the only species of the genus Hepatovirus of the Picornaviridae family. Belgium and European countries in general, are countries with a low prevalence and the majority of adults can be infected. HAV is mainly transmitted by the fecal-oral route and even if foodborne outbreaks account for less than 5 % of the reported cases per year, the source of infection cannot be identified in 50 % of the reported cases. Therefore the contribution of foodborne infection is probably underestimated. Viral loads in food samples are lower than in clinical samples and their detection requires refined molecular detection methods. Methods A one step real-time RT-PCR to detect HAV, with new primers (HAV F2 and HAV R2) and probe (HAV P2) was performed directly on HAV diluted suspensions and on food samples (dates) and was compared with a ready-to-use commercial kit. Before the one step real time RT-PCR, a preliminary step combining concentration of viral particles with polyethyleneglycol and centrifugation was used on food samples. Results Real time RT-PCR one step with HAV F2/R2/P2 is more efficient but less sensitive than the commercial kit. It could be used to confirm a positive sample or to detect HAV in an unknown sample. With cell cultured HAV, the limit of detection (LOD) is 1.25 infectious particles in volume tested by RT-PCR or 102 TCID50/ml. In food samples, LOD is between 25 infectious particles and 250 infectious particles in volume tested by RT-PCR or between 104 and 105 TCID50/ml. Several hypotheses could explain these results: the loss of viral particles during the extraction process, the low efficiency of RNA extraction and interference of food on molecular detection. Conclusion Molecular detection of virus in food samples remains a challenge and the protocol of extraction should be improved and adapted at each food category to increase the sensitivity of detection in food matrices characterized by a low viral contamination. [less ▲]

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See detailPreliminary results on in vitro murine norovirus susceptibility to Mx-mediated innate immunity
Mauroy, Axel ULiege; Garigliany, Mutien-Marie ULiege; Desmecht, Daniel ULiege et al

Poster (2012, September)

Objectives Murine norovirus (MuNoV) belongs to the family Caliciviridae, genus Norovirus and is currently used as study model for human noroviruses, major aetiologic agents of gastroenteritis worldwide ... [more ▼]

Objectives Murine norovirus (MuNoV) belongs to the family Caliciviridae, genus Norovirus and is currently used as study model for human noroviruses, major aetiologic agents of gastroenteritis worldwide. Myxovirus (Mx) protein is an interferon-induced protein that host cell can oppose virus infection and was detected in several species including human being. In mice, two genes encoding Mx1 and 2 proteins are present but it was evidenced that these genes were inactivated by deletions in several laboratory mouse strains. Mx antiviral activity was detected on several negative stranded RNA viruses but information are still lacking for most of positive stranded RNA viruses. In this study, the susceptibility of the MuNoV to specific and interspecific Mx proteins was investigated. Methods RAW264.7 cells (murine macrophages) were first tested for constitutive expression of Mx1 proteins. Plasmids containing the murine Mx1, bovine Mx1 and human MxA genes under the CMV immediate early promotor were then used to transfect RAW264.7 cells for transient Mx expression. Negative control consisted in a plasmid expressing eGFP. Four hours after transfection, cells were infected at low MOI with the CW1 MuNoV strain. Cells and supernatants were harvested 24h post infection. RNA was extracted and viral genomic copies were measured by real time RT-PCR. Results An effect was confirmed on CW1 replication for both specific and interspecific Mx proteins. The highest effect was obtained with the bovine Mx1 protein. Conclusion In conclusion, we showed in these preliminary in vitro studies the MuNoV susceptibility to specific and interspecific Mx proteins. Bovine Mx1 protein was already demonstrated to have important antiviral activity on negative stranded RNA viruses (influenza- and paramyxoviruses) and co-evolution with the host could explain a higher susceptibility to interspecific Mx proteins. Important implications of this adaptation could be expected on zoonotic concerns associated to NoV. Moreover, even if several control studies are still be conducted to validate these preliminary results, they could drive several pertaining questions on the MuNoV model used with laboratory mice. Perspectives of this work consist to validate the susceptibility in vivo and also to test the murine Mx2 antiviral activity on MuNoV. [less ▲]

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See detailMitigation Potential of Artificial Ocean Alkalinization For Ocean Acidification and Atmospheric CO2
Ilyina, Tatiana; Wolf-Gladrow, Dieter; Munhoven, Guy ULiege et al

Poster (2012, September)

Fossil fuel CO2 emissions result in climate change and ocean acidification. Enhanced weathering or artificial ocean alkalinization (AOA) has been proposed as a geoengineering method to mitigate further ... [more ▼]

Fossil fuel CO2 emissions result in climate change and ocean acidification. Enhanced weathering or artificial ocean alkalinization (AOA) has been proposed as a geoengineering method to mitigate further increase of atmospheric CO2 and decrease of ocean pH. A variant of AOA involves reacting carbonates and adding the dissolved materials into the upper ocean. The net effect of this approach is to increase ocean alkalinity, thereby increasing the oceanic capacity to store fossil fuel CO2. Another effect of adding alkalinity would be to drive seawater to higher pH values and thus counteract the ongoing ocean acidification. We test implications of AOA for marine carbon cycle using the global ocean biogeochemical model HAMOCC. In our model scenarios we add alkalinity in the amounts proportional to fossil fuel emissions. We show that large-scale AOA scenarios in which large amounts of alkalinity are added would be necessary to avoid a significant increase in atmospheric CO2 and to hold the global seawater pH close to today’s value. Even a short-term AOA would have long-lasting effects on seawater chemistry. When AOA stops, atmospheric CO2 (and pH) reverts back to rising (decreasing) at the rate determined by the fossil fuel CO2 emissions growth, but the effect of AOA is permanent. Hence, in contrast to SRM, effects of AOA on seawater chemistry and atmospheric CO2 retain after stopping alkalinity addition; AOA would not involve a long-term commitment. [less ▲]

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See detailExperimental Characterisation of Damage Occuring during Single Point Incremental Forming of a Ferritic Steel
Mertens, Anne ULiege; Guzmán Inostroza, Carlos Felipe ULiege; Habraken, Anne ULiege et al

Poster (2012, September)

Single Point Incremental Forming (SPIF) has been developed as a new dieless process for forming metal sheets. This technique appears very promising in view of the current requirements for rapid ... [more ▼]

Single Point Incremental Forming (SPIF) has been developed as a new dieless process for forming metal sheets. This technique appears very promising in view of the current requirements for rapid prototyping and/or small series production [1]. However, inaccuracies in the shape of the processed part and material failure constitute important limiting factors for applications. In the present research, a numerical approach, based on the damage model proposed by Gurson [2], has been chosen to analyse and optimise the process, predict the material rupture and the process limit. From experimental observations of plastic deformation and ductile fracture, damage is related to the nucleation, growth and coalescence of microvoids [3]. Gurson’s model uses the volume fraction of these voids as a main variable. Hence the determination of this value is a key factor for a correct identification and validation of the model. More particularly, the present work focuses on two different methods used to experimentally characterise damage occurring during single point incremental forming of a ferritic steel. Void measurements carried out by optical microscopy combined with image analysis have been compared with porosity values obtained from density measurements based on the Archimedes’ principle [4], so as to assess the feasibility of using this method for a quick characterisation of the damage. [less ▲]

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See detailMathematical Level-Set Modelling of Cell Growth on 3D Surfaces
Guyot, Yann ULiege; Papatoniou, Ioannis; Chai, Yoke Chin et al

Poster (2012, September)

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See detailThe 'Art of the States' Research Project: Performance Effects of Administrative Innovations in US State Governments
Markus, M. Lynne; Bui, Quang Neo; Jacobson, Dax D. et al

Poster (2012, September)

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See detailInfluence of sleep homeostasis and circadian rhythm on executive discriminative ability during a constant routine
Jaspar, Mathieu ULiege; Meyer, Christelle ULiege; Muto, Vincenzo ULiege et al

Poster (2012, September)

Introduction & Objectives The human brain upholds cognitive performance throughout a waking day due to putative circadian (C) arousal signal which counteracts the increase in homeostatic (H) sleep ... [more ▼]

Introduction & Objectives The human brain upholds cognitive performance throughout a waking day due to putative circadian (C) arousal signal which counteracts the increase in homeostatic (H) sleep pressure associated to the deterioration in brain efficiency. When wakefulness is extended into the circadian night, maintenance of cognitive performance is jeopardized . Some individuals are very vulnerable to the negative effects of sleep loss and circadian misalignment, whereas others are resilient. These individuals differences can be readily explained within the conceptual framework of the circadian and homeostatic regulation of performance but also by individual genetic differences and notably the PERIOD3 gene polymorphism. In this experiment, we investigated the consequences of sleep deprivation on cognitive performance during a working memory task (3-back). Following the signal detection theory, the ability to discriminate target from non-target stimuli is estimated by d prime (d') and criterion (cr). Here we assessed whether d' and cr were modulated by the raising sleep need and the oscillatory circadian signal. We also tested whether the individual vulnerability to sleep loss predicted by the PERIOD3 gene polymorphism influences this cognitive modulation, which is also driven by the sleep/wake regulation. [less ▲]

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See detailDoes processing speed protect from age-related decline in cognitive control?
Manard, Marine ULiege; Carabin, Delphine; Collette, Fabienne ULiege

Poster (2012, August 30)

Age-related difficulties have been reported on proactive control whereas reactive control seems to remain intact. This study investigated the potential influence of speed of processing abilities on the ... [more ▼]

Age-related difficulties have been reported on proactive control whereas reactive control seems to remain intact. This study investigated the potential influence of speed of processing abilities on the age-related decline in proactive control. We used a working memory recognition paradigm involving proactive or reactive cognitive control by manipulating the interference level across items. 80 young adults (18-29 years old) and 80 healthy older adults (60-89 years old) were included. Main results revealed significant effects of age on interference sensitivity. As expected, reactive control performance remained intact with aging (similar interference effect in the two groups). In contrast, we observed a larger interference effect in the proactive condition in aging. Finally, when the groups are matched according to their processing speed (assessed by the Code task of the WAIS III, with both younger and older adults having a score comprised between 60 and 93), the effect of age on sensitivity to interference disappeared. In other words, when younger and older adults had similar speed of processing abilities, no age-related proactive control decline was observed. In conclusion, beyond the fact that this study confirms the selective age-related decline in proactive control, it also indicates that speed of processing, a measure considered as reflecting the integrity of cognitive functioning during aging, influences the efficiency of proactive control in that population. [less ▲]

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See detailAn archaeology of 'Intersubjectivity'. Mapping conceptual splits in linguistics and beyond
Lttr13; Badir, Sémir ULiege; Polis, Stéphane ULiege et al

Poster (2012, August 30)

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See detailBioactive Intraocular Lens - A New Concept to Control Secondary Cataract
Huang, Yi-Shiang ULiege; Alexandre, Michaël ULiege; Bozukova, Dimitriya et al

Poster (2012, August 29)

A cataract is pathology opacity of the lens, causing impairment of vision or even blindness. Today, a surgery is still the only available treatment. The intraocular lens (IOL) is a polymer implant ... [more ▼]

A cataract is pathology opacity of the lens, causing impairment of vision or even blindness. Today, a surgery is still the only available treatment. The intraocular lens (IOL) is a polymer implant designed to replace the natural lens in the cataract surgery. The materials for IOL require excellent optical properties for light transmission, mechanical properties for folding injection during surgery, and biological properties for preventing body rejection. The biocompatibility - or more specified, bio-inert - seems to be the prerequisite in selecting the materials. [1] However, the bioinert materials could not satisfy the unmet need in the secondary cataract control. Posterior capsular opacification (PCO, or Secondary Cataract), characterized by a thick and cloudy layer of lens epithelial cells (LECs), is the most common postoperative complication. In 1997, a “Sandwich Theory” model was proposed to elucidate the developmental process of PCO. [2] In this model, the residual LECs between the lens capsular bag and the IOL undergo proliferation, migration, as well as transdifferentiation and finally induce PCO if the affinity to the IOL material is low. In our research, a bioactive molecule is introduced to the conventional acrylic hydrophilic polymer pHEMA(Poly(2-hydroxyethyl methacrylate)) by covalent conjugation. The RGD peptide sequence, being well-known for its tissue integration ability, is designed to stimulate the biointegration between the LECs and the IOL. [3]. Our data have shown the peptide grafted biomaterial not only exhibits similar optical and mechanical properties, but also reveals enhanced biological properties in cell adhesion and cell morphology maintenance. By means of surface functionalization of IOL to stabilize and restore LECs, the secondary cataract could be controlled in a regenerative medicine way. References [1] Dimitriya Bozukova (2010) Materials Science and Engineering R, 69: 63-83. [2] Reijo Linnola (1997) J Cataract Refract Surg., 10: 1539–42. [3] Ruoslahti E (1986) Cell, 44(4): 517-8. [less ▲]

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See detailMid-infrared predictions of fatty acids in bovine milk : final results of the RobustMilk project
Soyeurt, Hélène ULiege; McParland, Sinead; Berry, Donagh et al

Poster (2012, August 28)

The development of mid-infrared equations to predict the milk fatty acid (FA) content of milk allows prompt analysis of large numbers of samples and was one of the aims of the RobustMilk project. Data on ... [more ▼]

The development of mid-infrared equations to predict the milk fatty acid (FA) content of milk allows prompt analysis of large numbers of samples and was one of the aims of the RobustMilk project. Data on MIR spectra and FA from multiple countries, production systems, and breeds were used to develop equations to predict milk FA. The calibration set contained 1,776 spectrally different English, Irish, and Belgian milk samples collected for over 6 years. FA were quantified by gas chromatography (GC). Equations were built using partial least squares regression after a first derivative pretreatment applied to the spectral data. The robustness of the developed equations was assessed by cross-validation (CV) using 50 groups from the calibration set. The coefficient of determination (R²) obtained after CV ranged between 0.7101 for the total content of C18:2 and 0.9993 for the saturated FA group. The standard error of CV ranged between 0.0028 and 0.0998 g/dl of milk. Generally, the group or individual FA having the highest content in milk had the highest R²cv. The results obtained in this study confirmed the usefulness of MIR spectra to robustly quantify the FA content of milk permitting the use of these equations by milk laboratories in UK, Belgium or Ireland. Therefore, these equations could be used to develop selection or management tools for dairy farmers in order to improve the nutritional and environmental quality of milk based on the knowledge of the FA composition of their milk. [less ▲]

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See detailLong-term trends of NO above northern mid-latitudes as inferred from Jungfraujoch, HALOE and ACE-FTS solar observations
Demoulin, Philippe ULiege; Mahieu, Emmanuel ULiege; Servais, Christian ULiege et al

Poster (2012, August 27)

Routine FTIR solar observations are performed by the University of Liège at the Jungfraujoch station (Swiss Alps, 3580 m altitude, NDACC station) since 1985. The analysis of the recorded spectra allows to ... [more ▼]

Routine FTIR solar observations are performed by the University of Liège at the Jungfraujoch station (Swiss Alps, 3580 m altitude, NDACC station) since 1985. The analysis of the recorded spectra allows to derive total and partial columns of more than 20 different atmospheric gases. Among them, gases belonging to the total reactive nitrogen NOy (NO, NO2, HNO3 and ClONO2), to the total inorganic chlorine Cly (HCl and ClONO2) and to the total inorganic fluorine Fy (HF and COF2) families. In this communication, budgets of these gas families are investigated, and their short term, seasonal and inter-annual variations as well as their long-term trends are determined for the time period ranging from the mid-1980s up to the end of 2011. We also investigate the evolution of the same gases, when available, derived from ground-based UV-vis (1990-present) and from HALOE (1991-2004) and ACE-FTS (2004-present) satellite observations. We evaluate the consistency between the trends characterizing these various species, as deduced from the ground- and space-based time series. [less ▲]

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See detailLivestock farms in Belgium shelter they the mosquitoes (Diptera, Culicidae) potentially vectors of arboviruses?
Boukraa, Slimane ULiege; Zimmer, Jean-Yves ULiege; Simonon, Grégory et al

Poster (2012, August 23)

Although no major arbovirus which mosquitoes are responsible for its transmission has been recorded in Belgium in recent decades, environment and climate change, current and future, could favor the ... [more ▼]

Although no major arbovirus which mosquitoes are responsible for its transmission has been recorded in Belgium in recent decades, environment and climate change, current and future, could favor the emergence of vector-borne diseases in the country, by inducing changes on Culicidae populations. This study aims to determine the potential importance of agricultural environments, and especially livestock farms, to welcome and favor the proliferation of certain species of mosquito responsible for transmission of arboviruses. A taxonomic inventory was conducted in 2008 (III, VI and X) and 2009 (V and IX) in ten cattle farms, and in 2010 (X) in ten stables located in Belgium. The harvest of mosquitoes is based on larval sampling at the level of 14 biotopes such as water troughs, used tires, abandoned utensils and temporary puddles or not. The morphotaxonomic study of larvae and genitalia has allowed to identify eight species in 18 study stations. These are Anopheles claviger Meigen, 1804 ; A. maculipennis s.l. Meigen, 1818 ; Culiseta annulata Schrank, 1776 ; Cs. morsitans Theobald, 1901 ; Culex modestus Ficalbi, 1889 ; Cx. torrentium Martini, 1925 ; Cx. territans Walker, 1856 and Cx. pipiens s.l. L., 1758. Of the 1843 individuals examined in 2009, Cx. pipiens s.l. represents 79.98% of the total harvest; however, Cx. modestus represents only 0.92%. Used tires form the most favorable habitat for larval development of Culicidae. Therefore, despite the low diversity of mosquito observed within the livestock environments, they represent a significant risk for the reproduction of some potential vectors of arboviruses. In addition, some larval habitats constitute very favorable sites for proliferation of mosquito, causing a real problem of nuisance for animals of farms. [less ▲]

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See detailDetailed Seismic Hazard Assessment for The Central Tien Shan, Kyrgyzstan
Lamair, Laura ULiege; Havenith, Hans-Balder ULiege; Abdrakhmatov, K

Poster (2012, August 23)

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See detailTrophic and specific diversity of harpacticoid copepods associated to Posidonia oceanica macrophytodetritus
Mascart, Thibaud ULiege; De Troch, Marleen; Remy, François ULiege et al

Poster (2012, August 21)

Extended meadows of living Posidonia oceanica plants in the Mediterranean Sea produce large amounts of detritus of dead seagrass plants that are packed at the bottom of the sea. In spite of their large ... [more ▼]

Extended meadows of living Posidonia oceanica plants in the Mediterranean Sea produce large amounts of detritus of dead seagrass plants that are packed at the bottom of the sea. In spite of their large quantities, these phytodetritus are of low nutritional quality (high C:N:P ratio). However, these detritus are massively colonised by bacterial communities, fungi, diatoms, meiofauna and macrofauna. This leads to the assumption that those associated communities enrich the litter and play an important role in the energy transfer to higher trophic levels like macrofauna and juvenile fish that use these accumulations as nursery and feeding grounds. In these litter accumulations harpacticoid copepods (Crustacea) are the main meiofauna players (metazoans in the size range of 38µm – 1mm). Their families are characterised by different specialized morphologies (body form and appendages). Nonetheless their morphological differences they are all grazers and seem to feed on similar sources. Ecological theories state that diversity of trophic niches is an essential parameter to explain specific diversity. Therefore subtle trophic niches may occur among species assemblages, linked to the complexity of the phytodetritus. In order to unravel the ecological function, trophic relations, seasonal fluctuations and habitat interactions in these litter accumulations, a bulk stable isotope analysis (SIA) is conducted. The isotopic composition of C and N of the potential food sources and the most dominant harpacticoid copepod families are measured using an EA-IRMS coupling. The results are run in a SIAR Beyesian mixing model to calculate the approximate contributions of each potential food sources towards the composition of different families of harpacticoid copepods present in the macrophytodetritus. [less ▲]

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See detailYou’re not my dad, you’re my coach! When Paternalism Impairs Agility Performance
Silvestre, Aude ULiege; Dardenne, Benoît ULiege

Poster (2012, August 21)

Objectives: We were interested in the impacts of coach’s paternalistic motivational speech on young high performance sportsmen and sportswomen. We suggested that their motor performance (agility test ... [more ▼]

Objectives: We were interested in the impacts of coach’s paternalistic motivational speech on young high performance sportsmen and sportswomen. We suggested that their motor performance (agility test) would be diminished. Design: We used a 2 (paternalism: presence vs. absence) X 2 (valence: positive vs. negative) design to create four types of motivational speech. Methods: 60 participants read a description of an invented collective sport, followed by the coach’s motivational speech. After reading those texts, they were asked to do a motor agility test. They also had to complete an emotional measure on a 7-point Likert scale. We used linear regression as well double mediation macros in order to test the impacts of the coach’s paternalistic motivational speech on agility performance. Results: The results revealed direct effects of paternalism and valence on two measures of agility performance. Agility performance was worse when the speech was paternalistic (vs. no paternalistic) as well as when the speech was negative (vs. positive). When we compared negative paternalistic speech with the 3 others, we found that the direct effect of negative paternalism on performance is serially mediated, first by anxiety and, second by feeling of (in)competence. Conclusions: Acting in a fatherlike attitude might look like a good idea to motivate a sport team, using a little bit of father authority. But by doing so, in a negative way, the risk is that the team might perform badly instead. [less ▲]

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See detailIdentification of new microbial enzymes from forest and marine ecosystems by functional metagenomics
Martin, Marjolaine ULiege; Biver, Sophie ULiege; Barbeyron, Tristan et al

Poster (2012, August 21)

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See detailTrophic tracers reveal considerable diversity among diets of dominant amphipods from Posidonia oceanica seagrass meadows
Michel, Loïc ULiege; Dauby, Patrick ULiege; Gobert, Sylvie ULiege et al

Poster (2012, August 20)

Mediterranean Posidonia oceanica meadows shelter a high biomass and an important biodiversity of amphipod crustaceans. In other temperate meadows, the amphipods play an important part in the functioning ... [more ▼]

Mediterranean Posidonia oceanica meadows shelter a high biomass and an important biodiversity of amphipod crustaceans. In other temperate meadows, the amphipods play an important part in the functioning of the ecosystem, notably in organic matter transfers from producers to higher level consumers. However, the situation in Posidonia oceanica meadows remains unclear, and little is known about the trophic ecology of amphipods, which are generally regarded as generalist herbivores/detritivores despite the lack of precise studies. Here, we combined gut content examination and trophic markers (fatty acids, stables isotopes of C and N) to delineate the diet of the dominant species of amphipods from Posidonia oceanica seagrass meadows and to highlight trophic diversity among this community. Our results indicate that contribution of microepiphytic diatoms and of benthic and suspended particulate organic matter to the diet of amphipods were anecdotal. On the other hand, all dominant species heavily relied on macroalgal epiphytes, suggesting a certain extent of overlapping in the diets of the dominant species. Considerable interspecific differences nonetheless existed, notably concerning grazing preferences towards epiphytes from leaves or litter fragments vs. epiphytes from rhizomes. In addition, the use of the SIAR isotopic mixing model showed that most species had a mixed diet, and relied on several food items. None of the examined species seemed to graze on their seagrass host, but Gammarus aequicauda partly relied on seagrass leaf detritus. Overall, our findings demonstrate that amphipods have the potential to be key-items in trophic and functional interactions occurring among Mediterranean Posidonia oceanica meadows. [less ▲]

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See detailLeaf fall impact on diversity and trophic ecology of vagile macrofauna associated with exported P.oceanica litter
Remy, François ULiege; Mascart, Thibaud ULiege; Dauby, Patrick ULiege et al

Poster (2012, August 20)

In the Mediterranean Sea, Posidonia oceanica meadows produce a huge amount of detritus, evaluated up to 300 to 2000 g dry wt m-2 yr-1. This litter is mainly composed of dead leaves but also of uprooted P ... [more ▼]

In the Mediterranean Sea, Posidonia oceanica meadows produce a huge amount of detritus, evaluated up to 300 to 2000 g dry wt m-2 yr-1. This litter is mainly composed of dead leaves but also of uprooted P.oceanica shoots and drift macro-algae from adjacent rocky bottoms. Although rich in refractory materials (lignin) and poor in P and N, these underwater accumulations of leaves are colonised by fungi, micro-algae (like diatoms), bacteria, but also by micro and macrofauna assemblages. These organisms could play an important role in leaf litter degradation and enrichment, but also in energy and carbon transfer from P.oceanica to higher trophic levels in adjacent coastal ecosystems. In this study we focus on the vagile macro-fauna (invertebrates with a size > 500µm) inhabiting the exported litter accumulations of the Calvi Bay (France). We took standardised samples at two different sites (a sheltered one and an exposed one) before and after leaf fall. We emphasised that crustaceans represent 65 – 85% of the biodiversity, followed by annelids and molluscs, representing respectively 10-20% and 10-15% of the diversity. That general pattern differs between sampling sites and we highlighted changes after leaf fall at both sites. In order to assess the impact of the autumn period litter input on the trophic structure of these invertebrates, we conducted gut contents observations and “bulk” stable isotope analysis. The isotopic compositions of C and N stable isotopes of the potential detritic food sources and of the most abundant invertebrate’s species were measured using EA-IRMS. We finally focused on the two most abundant Gammaridean Amphipoda species representing up to about 60% of the vagile macrofauna found in litter accumulations: Gammarella fucicola and Gammarus aequicauda. The results of their isotopic measurements were used in the “SIAR” Bayesian mixing model to calculate the potential contribution of their potential food sources. [less ▲]

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See detailIMPACT OF DEPTH AND SOIL COMPACTION ON BACTERIAL DIVERSITY IN SOIL
Stroobants, Aurore ULiege; Degrune, Florine; Olivier, Claire et al

Poster (2012, August 19)

Bacteria are the most abundant and diverse microorganisms in soils. The amount of bacteria in soils can reach 10^10 cells per gram of soil. These organisms are involved in various processes in ... [more ▼]

Bacteria are the most abundant and diverse microorganisms in soils. The amount of bacteria in soils can reach 10^10 cells per gram of soil. These organisms are involved in various processes in agroecosystems such as nutrient cycling, contributing to plant nutrition, plant health and soil structure. The knowledge about this diversity is limited because only one percent of these organisms can be cultured by laboratory methods. During the last decades, many molecular-based techniques have been developed to assess the diversity of bacterial communities. The aim of this study was to determine the quantity and diversity of bacteria in two agricultural soils with differents soil management practices (tillage and no tillage) at different depths (10, 30 and 45 centimeters) and different compaction levels (high and low). Quantity was evaluated by real time PCR and diversity was analysed by the DGGE (Denaturing Gradient Gel Electrophoresis) technique. The results show that soil management has an impact on bacterial quantity at 45 centimeters and quantity is higher in till soil. Compaction level affects the bacterial quantity in till soil, quantity is higher in low compaction. And finally, depth influences the bacterial quantity in till and no till soil. In both soils, quantity decreases with the depth. The results will be presented and discussed on the poster. [less ▲]

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See detailSTUDY OF BACTERIAL DIVERSITY IN AN AGRICULTURAL SOIL
Stroobants, Aurore ULiege; Bodson, Bernard ULiege; Portetelle, Daniel ULiege et al

Poster (2012, August 19)

Bacterial growth in soil is dependent on soil characteristics. In this experiment, we have studied the evolution of bacterial diversity during a winter wheat crop and the impacts caused by the tillage and ... [more ▼]

Bacterial growth in soil is dependent on soil characteristics. In this experiment, we have studied the evolution of bacterial diversity during a winter wheat crop and the impacts caused by the tillage and residue incorporation. Three growth stages of wheat was chosen for this work : germination, tillering and booting. The analyse of bacterial diversity in these conditions was performed by the Next Generation Sequencing technology. Results obtained by this method indicate that the soil is composed, in average, by 38,02 (±4,81)% Proteobacteria; 19,71(±3,88)% Actinobacteria; 7,77(±1,44)% Firmicutes; 6,94(±1,58)% Fibrobacteres/Acidobacteria group; 5(±3,21)% Bacteroidetes/Chlorobi group; 3,89(±1,36)% Chloroflexi; 2,96(±0,67)% Planctomycetes; 2,87(±1,58)% Verrucomicrobia; 1,42(±0,41)% Cyanobacteria and 15,38(±2,64)% others. The tillage influences mostly the Deltaproteobacteria, Gammaproteobacteria, Actinobacteridae, Bacteroidetes/Chlorobi group and Verrucomicrobia. Residue incorporation has an impact on Betaproteobacteria, Gammaproteobacteria, Actinobacteridae, Acidimicrobidae, Firmicutes and Bacteroidetes/Chlorobi group. The wheat growth stages affect especially Betaproteobacteria, Deltaproteobacteria, Actinomycetales, Acidibacteria, Fibrobacteres and Bacillales. The results will be presented and discussed on the poster. [less ▲]

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See detailOpening the archaeal box in a oligotrophic freshwater environment
Llirós, M; Garcia-Armisen, T; Crowe, SA et al

Poster (2012, August 19)

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See detailPathogenicity test of the fungus Aspergillus clavatus on aphid Acyrthosiphon pisum (Aphididae)
Seye, Fawrou; Bawin, Thomas ULiege; Delvigne, Frank ULiege et al

Poster (2012, August 19)

Pea aphid is a pest of many cultivated and wild plants, but also a vector of several viral diseases. To control this pest, the most widely used methods are physical, chemical and more recently an ... [more ▼]

Pea aphid is a pest of many cultivated and wild plants, but also a vector of several viral diseases. To control this pest, the most widely used methods are physical, chemical and more recently an integrated approach that includes biological control. With the use of pathogenic agents against insects, the use of entomopathogenic fungi is one of the most promising. The present study demonstrated the possibility of using an entomopathogenic fungus Aspergillus clavatus against aphids. In laboratory conditions (8/16 photoperiod, average temperature 25°C), the insects were in contact with different concentrations ranging from 10^2 to 10^4 spores/cm2 deposited on filter paper in Petri dishes, or applied directly to young plants with doses ranging from 10^4 to 10^6 spores/ml. In 24 hours, mortality was 0 to 31.5% in Petri dishes. For treatment plants, the cumulative mortality in 5 days was 55 to 79%. Microscopic observations showed that the aphids were infected by contact and fungus has a mycosis effect. From these preliminary results, investigations should be made to study the action of the fungus on the reproduction of aphids. Therefore, A. clavatus could be introduced along with other fungi found in the literature as a biological control agent against aphids. [less ▲]

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See detailInteractions between western lowland gorillas (Gorilla gorilla gorilla Savage & Wyman 1847) and timber exploitation: Preliminary insights in a Gabonese logging concession
Haurez, Barbara ULiege; Petre, Charles-Albert ULiege; Doucet, Jean-Louis ULiege

Poster (2012, August 15)

Interactions between western lowland gorillas (WLG) and a timber exploitation were studied in Central Gabon. WLG densities were estimated in two sites with different logging histories (not logged vs ... [more ▼]

Interactions between western lowland gorillas (WLG) and a timber exploitation were studied in Central Gabon. WLG densities were estimated in two sites with different logging histories (not logged vs. logged one month before), and nesting behavior was described. Seeds dispersed by WLG were identified through fecal analysis and germination trials assessed seed viability after gut passage. Four treatments were realized for the most abundant species: passed seeds, passed seeds in fecal matrix, seeds surrounded by fresh pulp and seeds extracted from fresh fruits. Relatively high WLG densities were observed in the concession (3.7 weaned gorillas/km² in unlogged forest and 1.7 weaned gorillas/km² in logged forest). WLG nested preferentially in open areas (particularly open terra firme and swamp forest) and frequently used old logging road network for nesting and feeding. WLG dispersed sixteen species during the course of the study (February-May 2011). The most dispersed species was Santiria trimera (Burseraceae). The germination successes of S. trimera were significantly higher after gut passage (N=378; P<0.001) because of pulp removal and seed coat scarification. This pilot study suggests that timber exploitation and WLG conservation are not mutually exclusive. WLG are important agents of forest regeneration by dispersing seeds in logged areas. Nest sites in logging gaps could be particularly favorable for seedlings development. This consideration must encourage forest managers to strengthen WLG-conservative practices in their concessions. [less ▲]

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See detailEffect of duration and temperature of previous vacuum-packed storage on the oxidative stability of Belgian Blue meat packed in high-oxygen atmosphere
Didimo Imazaki, Pedro Henrique ULiege; Tahiri, Assia ULiege; Thimister, Jacqueline ULiege et al

Poster (2012, August 13)

The aim of this experiment was to study the effect of duration and temperature of previous vacuum-packed (VP) storage on the oxidative stability of Belgian Blue meat packed in high-oxygen atmosphere. VP ... [more ▼]

The aim of this experiment was to study the effect of duration and temperature of previous vacuum-packed (VP) storage on the oxidative stability of Belgian Blue meat packed in high-oxygen atmosphere. VP striploins from bulls and cows were stored at −1 °C and +4 °C for up to 80 days and analyzed. These same meat samples were also repackaged under modified atmosphere (MA) – 70 % O2/30 % CO2 – at different times, stored 2 d at +4 °C and 5 d at +8 °C, and then analyzed. Meat from cows presented a lower loss of redness than meat from bulls. A low lipid oxidation was observed in VP samples, but an increase of lipid oxidation took place after MA repackaging. Meat from cows presented a higher -tocopherol content. A decrease of α-tocopherol content during storage was observed as well. The fat content was also higher in meat from cows than in meat from bulls. The duration and temperature of vacuum-packed storage influenced the sensitivity of Belgian Blue beef to pigment and lipid oxidation during subsequent high-oxygen storage. [less ▲]

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See detailRisk of introduction of alphaviruses responsible for American equine encephalitides in Belgium
De la Grandière de Noronha Cotta, Maria Ana ULiege; Dal Pozzo, Fabiana ULiege; Francis, Frédéric ULiege et al

Poster (2012, August)

Arthropod-borne viruses are a threat for human and animal healths in regards with their dissemination out of their endemic area. The arboviruses reviewed here belong to the family Togaviridae genus ... [more ▼]

Arthropod-borne viruses are a threat for human and animal healths in regards with their dissemination out of their endemic area. The arboviruses reviewed here belong to the family Togaviridae genus Alphavirus and are small enveloped positive sense RNA viruses. They are considered as exotic equid pathogens in Europe and can cause severe diseases in humans in the context of an epidemic. Arboviruses have complex epidemiologic features characterised by interactions between viruses, vectors, reservoir or susceptible host species, and environment. A bibliographic search was performed to identify the mean factors that influenced past outbreaks in America and the presence of potential vectors/vertebrate hosts that could play a role in the transmission cycle in Belgium. Three equine arboviruses, currently considered as the main current threats of emergence/introduction in Western Europe, were chosen as model for this study: Eastern equine encephalitis virus (EEEV), Western equine encephalitis virus (WEEV) and Venezuelan equine encephalitis virus (VEEV). In conclusion, taking into consideration the globalisation (increase of international exchanges) and climate warming, the analysis of the different features of the arbovirus cycles are essential to a balanced risk expertise in the Belgian context. Research supported by the Belgium Federal Public Service, Health, Food Chain Safety and Environment. [less ▲]

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See detailGenetics and genomics of energy balance measured in milk using mid-infrared spectroscopy
McParland, Sinead; Calus, Mario; Coffey, Mike et al

Poster (2012, August)

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See detailTermites artificially-fed on unusual diet and resulting enzymatic switches
Bauwens, Julien ULiege; Tarayre, Cédric ULiege; Matteotti, Christel et al

Poster (2012, August)

Wood-feeding termites as Reticulitermes santonensis generally feed on cellulose, hemicelluloses and lignin. However, these opportunistic insects are also able to degrade other carbohydrates, such as ... [more ▼]

Wood-feeding termites as Reticulitermes santonensis generally feed on cellulose, hemicelluloses and lignin. However, these opportunistic insects are also able to degrade other carbohydrates, such as starch. The production of putative endogenous α - amylase has been previously shown in R. flavipes, as the disappearance of the major symbiotic flagellates from the hindgut. Here, we compared enzymatic activities (CMCase, MCCase, xylanase, amylase, α- and β-glucosidase) between different fractions of the digestive tract of starch-, cellulose-, and wood-fed termites. Main compounds of the artificial diets, namely starch or MCC, resulted in differential enzymatic activity. Even the substitution of wood by artificial diets itself seemed to induce changes in enzymatic activities, regardless of the main substrate in the diet, as we observed strong midgut α-glucosidase activity only for artificially-fed termites. Preliminary assays to isolate and characterize enzymes were performed using proteomic methods. [less ▲]

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See detailHepatitis E virus infection in domestic swine in Belgium
Thiry, Damien ULiege; Mauroy, Axel ULiege; Brochier, Bernard et al

Poster (2012, August)

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See detailCharacterization of Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) overwintering sites
Fassotte, Bérénice ULiege; Durieux, Delphine ULiege; Francis, Frédéric ULiege et al

Poster (2012, August)

Originally introduced as a biological control agent, the multicoloured Asian ladybeetle, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), has become an invasive pest throughout Europe and North ... [more ▼]

Originally introduced as a biological control agent, the multicoloured Asian ladybeetle, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), has become an invasive pest throughout Europe and North America in the last few years. Although its effectiveness to control aphid and coccid populations was impressive, some negative impacts appeared rapidly, notably on human health. Indeed, to protect themselves from cold temperatures, H. axyridis individuals move inside dwellings and buildings and form large aggregations in concealed portions of structures to overwinter. The aggregating beetles are responsible for some annoyances due to, on one hand, the number of individuals inside homes and, on the other hand, the hemolymph secretions they release when they are disturbed, which can cause allergic reactions. In order to highlight the specific features of infested houses, we investigated a large number of overwintering sites in Wallonia between 2007 and 2011. These sites were characterized through a survey sent to homeowners confronted to invasion problems. This survey was mainly focused on a general description of the infested house (type, colour, infested floor(s), building material), the orientation of the colonized rooms and the position of the beetles’ cluster. The collected data indicate that H. axyridis preferentially selects isolated brick houses with red or white fronts to take shelter. Aggregations are mostly located at the first floor, essentially inside south, west or southwest oriented rooms. Furthermore, ladybeetles generally gathered into wooden windows frames facing south, west or southwest and to a lesser extent, in the upper corners of walls presenting the same orientation. All these results contribute to improve the knowledge on the aggregative behaviour of H. axyridis and could promote the development of more specific and efficient management methods to prevent massive infestations into dwellings, such as artificial shelters or trapping systems located at the outside of buildings. [less ▲]

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See detailOzone tropospheric and stratospheric trends (1995-2011) at six ground-based FTIR stations (28°N to 79°N)
Vigouroux, Corinne; De Mazière, Martine; Demoulin, Philippe ULiege et al

Poster (2012, August)

Five ground-based stations in Western Europe, from 79°N to 28°N, all part of the Network for the Detection of Atmospheric Composition Change (NDACC), have joined their efforts to homogenize and optimize ... [more ▼]

Five ground-based stations in Western Europe, from 79°N to 28°N, all part of the Network for the Detection of Atmospheric Composition Change (NDACC), have joined their efforts to homogenize and optimize the retrievals of ozone profiles from FTIR (Fourier transform infrared) solar absorption spectra. Using the optimal estimation method, distinct vertical information can be obtained in four layers: ground—10 km, 10—18 km, 18—27 km, and 27—42 km, in addition to total column amounts. Vigouroux et al. (2008) applied a bootstrap resampling method to the ozone data to determine the trends of the total columns and of the partial columns in the above four layers, over the period 1995-2004. The updated trends for the period 1995-2009 have been published in the WMO 2010 report. Here, we present the updated trends, obtained using the bootstrap resampling method, for the 1995-mid-2011 period, for the five European stations and also for the station Thule, Greenland (77°N), which has joined this effort. The trends have also been estimated using a multiple regression model including the Quasi Biennial Oscillation (QBO) and the solar flux as explanatory variables. The trends obtained by the two methods will be compared and discussed. One of the major results is the significant positive trend observed in the upper stratosphere at the station Jungfraujoch (47°N), which provides a sign of ozone recovery at mid-latitudes. Significant positive trends are also observed in the upper stratosphere at the high latitude stations. [less ▲]

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See detailFeeding humans with edible insects : actual state and perspectives in Belgium and Europe
Sablon, Ludovic ULiege; Alabi, Taofic; Drugmand, Didier et al

Poster (2012, August)

In future decades, world population will grow up to 9 billion of people and we will be confronted to a lack of nutritive resources. We will not continue to produce proteins with our conventional livestock ... [more ▼]

In future decades, world population will grow up to 9 billion of people and we will be confronted to a lack of nutritive resources. We will not continue to produce proteins with our conventional livestock as beef, poultry or pig. It will therefore look to other sources and edible insects are one of these solutions. Indeed, more than 2000 species of edible insects were actually consumed by 3000 ethnic groups in the world. In undernourished populations, entomophagy is essential to relieve deficiencies in proteins, fatty acids and some vitamins. In Europe, we have acquired sedentary habits and we have lost our ancestral harvesting and hunting traditions. It is the reason of disinterest for edible insects and entomophagy was considered as a "barbarian" food habit. Facing food challenges of tomorrow, it is important to sensitize industrialized populations and to reintroduce edible insects in our plates and habits. The first step is to overcome neophobia of food products. Our studies focused on different insect preparations and on perception of entomophagy by different age classes. Globally, our first results indicated that entomophagy was accepted by belgian consumers but the more difficult for them is to taste the first time. These results confirmed neophobia for this type of food products and thus the importance of positive informations and education for acceptance of entomophagy. [less ▲]

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See detailEffect of reduced water supply on aphid physiology : A proteomic approach on peach-aphid interaction
Verdugo, Jaime; Lacroze, Jean-philippe; Sauge, Marie-Hélène et al

Poster (2012, August)

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See detailRetrievals of ethane from ground-based high-resolution FTIR solar observations with updated line parameters: determination of the optimum strategy for the Jungfraujoch station.
Bader, Whitney ULiege; Perrin, Agnès; Jacquemart, David et al

Poster (2012, August)

Ethane (C2H6) is the most abundant Non-Methane HydroCarbon (NMHC) in the Earth’s atmosphere, with a lifetime of approximately 2 months. C2H6 has both anthropogenic and natural emission sources such as ... [more ▼]

Ethane (C2H6) is the most abundant Non-Methane HydroCarbon (NMHC) in the Earth’s atmosphere, with a lifetime of approximately 2 months. C2H6 has both anthropogenic and natural emission sources such as biomass burning, natural gas loss and biofuel consumption. The retrieval of ethane from ground-based infrared spectra is challenging. Indeed, ethane has a complicated spectrum with many interacting vibrational modes and the current state of ethane parameters in HITRAN (see http://www.hitran.com) was rather unsatisfactory in the 3 μm region. In fact, PQ branches outside the 2973–3001 cm-1 range are not included in HITRAN, and most P and R structures are missing. New ethane absorption cross sections recorded at the Molecular Spectroscopy Facility of the Rutherford Appleton Laboratory (Harrison et al., 2010) are used in our retrievals. Pseudoline parameters fitted to these ethane spectra have been combined with HITRAN 2004 line parameters (including all the 2006 updates) for all other species encompassed in the selected microwindows. We evaluated the impact on spectral residuals induced by the update of two O3 lines (encompassed in the PQ3 µ-window) corrected by P. Chelin (LPMA, Paris, France). We also quantified the improvement brought by the update of the line positions and intensities of methyl chloride (CH3Cl) in the 3.4 µm region (Bray et al., 2011). The ethane a priori volume mixing ratio (VMR) profile and associated covariance are based on synthetic data from CHASER 3-D chemical transport model (CTM). In this contribution, we will present updated ethane (total) column retrievals, using the SFIT-2 algorithm (v3.91) and high-resolution Fourier Transform Infrared (FTIR) solar absorption observations recorded with a Bruker 120HR instrument, at the high altitude research station of the Jungfraujoch (46.5°N, 8°E, 3580 m asl), within the framework of the Network for the Detection of Atmospheric Composition Change (NDACC, visit http://www.ndacc.org). Comparisons with synthetic data produced by two chemical transport models (CHASER and the one of the University of Oslo) will also be presented and analyzed, aiming at the determination and interpretation of long-term trends and interannual variations of ethane at Northern mid-latitudes. [less ▲]

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See detailThe use of participatory approaches to evaluate the socio-economic factors impairing the efficacy of animal health surveillance systems
Delabouglise, Alexis; Antoine-Moussiaux, Nicolas ULiege; Phan Dang, Thang ULiege et al

Poster (2012, August)

The need to set up efficient and sustainable surveillance networks is a major concern which must be continually placed at the heart of the overall issue of development. In developing countries, the ... [more ▼]

The need to set up efficient and sustainable surveillance networks is a major concern which must be continually placed at the heart of the overall issue of development. In developing countries, the political priority to reduce poverty means that it is vital to include social aspects in public decision making on health management in general. This focus on social aspects can be considered all the more important regarding surveillance as it is deeply embedded in agents’ everyday life. The flow of information about animal health involves different non-monetary costs, ensuing from stigmatization or from social pressure to withhold or disclose information. Understanding, measuring and alleviating these social costs of information is required to ensure the effectiveness and viability of surveillance. The present study considers the case of highly pathogenic avian influenza surveillance in Vietnam. It aims at establishing a protocol allowing for understanding and quantifying social costs incurred by surveillance agents at the community level. In this prospect, tools and concepts from anthropology, participative epidemiology and experimental economics were combined. More particularly, social network analysis, participatory observation, companion modeling and stated preference surveys were applied for the thorough examination of constraints and costs of health information flows. The opportunity for the scaling-up of such methodologies and for the inclusion of the so-elicited quantitative values in socio-economic evaluation of surveillance systems are discussed. [less ▲]

Detailed reference viewed: 68 (17 ULiège)
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See detailFinding the roots of adolescent violence: A test of two developmental pathways
Veronneau, Marie-Helene; Glowacz, Fabienne ULiege; Born, Michel ULiege

Poster (2012, August)

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See detailVolatile organic compounds released by barley roots attract wireworms
Barsics, Fanny ULiege; Fiers, Marie ULiege; Francis, Frédéric ULiege et al

Poster (2012, August)

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

Wireworms, the soil dwelling larvae of click beetles, are pests of many crops worldwide. Alternatives to insecticide treatments are needed for integrated management strategies. Our work consists in elucidating the role of barley (Hordeum vulgare L.) root-emitted volatile organic compounds (VOC) on the orientation behaviour of Agriotes sordidus Illiger wireworms (Fig. 1). Using dual choice olfactometers, we have evaluated the attractiveness of baits ranging from barley roots themselves to one isolated root-emitted volatile organic compound. [less ▲]

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See detailDioxins in human milk from different regions of France: Pilot of the French longitudinal study of children (ELFE).
Bidondo, ML; Focant, Jean-François ULiege; Saoudi, A et al

Poster (2012, August)

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See detailBreeding sites of main Bluetongue virus vectors in Belgian cowshed
Zimmer, Jean-Yves ULiege; Saegerman, Claude ULiege; Losson, Bertrand ULiege et al

Poster (2012, August)

Bluetongue (BT) is an emerging vectorborne disease of ruminants that was reported in August 2006 in northern Europe. Since 2007, BT virus (BTV) serotype 8 continued its spread across Europe and caused ... [more ▼]

Bluetongue (BT) is an emerging vectorborne disease of ruminants that was reported in August 2006 in northern Europe. Since 2007, BT virus (BTV) serotype 8 continued its spread across Europe and caused considerable economic losses. This observation indicates possible overwintering of the vector from year to year. The biological vectors of BTV are biting midges of the genus Culicoides. Breeding sites of bluetongue vector species have been found near farms (e.g. silage residues) and in neighboring meadows (e.g. cattle dung) but never inside sheds. We conducted a study in five cattle farms in Belgium during February–October 2008. Three samplings were performed and each soil sample collected inside cowsheds was incubated to enable adult midges to emerge. Among 15 soil biotopes sampled, only one showed the emergence of adult Culicoides biting midges: dried dung adhering to walls inside animal enclosures and resulting to the partial removal of used animal litter. It was a breeding site for the C. obsoletus/C. scoticus complex. Physico-chemical characteristics showed that midges of this complex are more prevalent in soil samples with a high carbon:nitrogen (C:N) index. So Culicoides biting midges are able to complete their life cycle in animal enclosures. We identified a breeding site for the primary BTV vector in a cowshed in northern Europe. These observations could explain the persistence of BTV from year to year despite fairly harsh winters. Hygienic measures on farms could reduce biting midges populations and so improve efficacy of vaccination campaigns against BT in Europe. [less ▲]

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See detailDevelopment of original 2-aryloxy/arylamino-5-cyanobenzenesulfonylureas as thromboxane A2 receptor antagonists
Bambi Nyanguile, Sylvie-Mireille ULiege; Hanson, Julien ULiege; Dogné, Jean-Michel et al

Poster (2012, August)

A series of novel 2-aryloxy/arylamino-5-cyanobenzenesulfonylureas were synthesized. The newly synthesized compounds were tested in vitro and ex vivo as thromboxane A2 receptor antagonists. Some of the ... [more ▼]

A series of novel 2-aryloxy/arylamino-5-cyanobenzenesulfonylureas were synthesized. The newly synthesized compounds were tested in vitro and ex vivo as thromboxane A2 receptor antagonists. Some of the test compounds showed potent thromboxane A2 receptor antagonist activity. Three compounds (7h, 8h and 8e) were identified as leads for further pharmacological and toxicological studies. [less ▲]

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See detailFirst steps of a new methodology for integrating ground-based ozone profile data
Pastel, M.; Godin-Beekmann, S.; Mahieu, Emmanuel ULiege et al

Poster (2012, August)

A new methodology is developed for integrating complementary ground-based data sources to provide consistent ozone vertical distribution time series as well as tropospheric and stratospheric ozone partial ... [more ▼]

A new methodology is developed for integrating complementary ground-based data sources to provide consistent ozone vertical distribution time series as well as tropospheric and stratospheric ozone partial columns. Primary results are presented for the Alpine station of the Network for the Detection of Atmospheric Composition Changes (NDACC). Ozone measurements from the lidar at Haute-Provence Observatory, the microwave spectrometer at Bern and the FTIR spectrometer at the Jungfrauch station are used for this purpose. First step is to evaluate the validity domain of ozone profile data considered here by assessing instrumental error and vertical resolution. Each instrument has its own vertical resolution; therefore adjustments need to be done for the creation of an homogeneous data set. Indeed, because of the higher resolution of lidar measurements, smoothing of the data is necessary for the comparison with FTIR and microwave measurements. However, smoothing the data induces a loss of scientific information. Therefore a compromise has to be established and discussed. The various intercomparisons provide an evaluation of the differences due to instrumental error and atmospheric variability. The statistical method used for combining the different measurements in order to obtain ozone vertical profile time series consistent with total ozone measurements is then discussed. [less ▲]

Detailed reference viewed: 13 (2 ULiège)
See detailAnimal circus: de dierenwereld in de poëzie van Hans Faverey
Dieu, Véronique ULiege

Poster (2012, August)

Detailed reference viewed: 19 (3 ULiège)
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See detailDevelopment of noninvasive genetic identification methods and polymorphic microsatellites for the Pyrenean desman (Galemys pyrenaicus)
Gillet, François ULiege; Cabria Garrido, Maria Teresa; Némoz, Mélanie et al

Poster (2012, August)

The Pyrenean desman (Galemys pyrenaicus) is probably one of the most threatened European mammal species. This small insectivorous and semi-aquatic species is endemic to the Pyrenean Mountains and of the ... [more ▼]

The Pyrenean desman (Galemys pyrenaicus) is probably one of the most threatened European mammal species. This small insectivorous and semi-aquatic species is endemic to the Pyrenean Mountains and of the north of the Iberic Peninsula. Many biologic aspects of this species are currently suffering from a major lack of information, particularly those concerning its genetics. Therefore the implementation of conservative efforts for the Pyrenean Desman remains extremely difficult. In order to improve the knowledge of this vulnerable species and notably, to better understand its distribution area, the first aim of our research was to develop non invasive genetic identification methods based on faeces. The second aim was the development of several polymorphic microsatellites markers in order to have a first look at the genetic structure of the Pyrenean Desman in its French distribution area. The identification methods were developed on the basis of the sequencing of a small mitochondrial DNA (cyt b) fragment as well as a RFLP method. These approaches led to the identification of the Pyrenean desman and to the differentiation of the latter from two other species living in the same type of habitat, the white-throated dipper (Cinclus cinclus) and the water shrew (Neomys fodiens). More than fifteen polymorphic microsatellites markers could be found for the Pyrenean Desman and their genotyping revealed a low number of alleles per locus (two to five). The results of this preliminary work tend to show a low genetic diversity for the Pyrenean Desman but this result needs to be confirmed in the future with a more extended and complete study. [less ▲]

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See detailBehavioral response of Harmonia axyridis towards their footprints according to their physiological state
Durieux, Delphine ULiege; Fassotte, Bérénice ULiege; Vanderplanck, Maryse ULiege et al

Poster (2012, August)

In order to survive cold, the multicolored Asian ladybeetle, Harmonia axyridis (Pallas), aggregates inside dwellings during winter. It has been recently highlighted that overwintering H. axyridis ... [more ▼]

In order to survive cold, the multicolored Asian ladybeetle, Harmonia axyridis (Pallas), aggregates inside dwellings during winter. It has been recently highlighted that overwintering H. axyridis individuals lay an area marking while walking, which is used by conspecifics to locate aggregation sites. These footprints are made-up of hydrocarbons, comprising both saturated and unsaturated homologues. However, it has not been demonstrated whether this “following area marking” behavior is specific to the overwintering individuals. The work presented herein was oriented to the study of the chemical evolution of these footprints according to the physiological state of H. axyridis. Monthly GC-MS analyses revealed that the area marking contained a greater amount of di-unsaturated compounds when laid by overwintering ladybeetles, suggesting the great importance of these chemicals in the ladybeetles aggregation process. In the second instance, behavioral investigations conducted in a Y-shaped glass tube were performed to assess (1) the evolution of H. axyridis behavior towards their footprints and (2) whether this behavioral modification is due to an evolution of the ladybeetles sensitivity or rather to an evolution of the area marking attractiveness. The results revealed that only the overwintering individuals follow their area marking, and that this behavior is linked to the ladybeetle physiological state rather than to the chemical profile of the marking biomolecules. [less ▲]

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See detailRole of aphid endosymbionts on virus transmission efficiency
Bosquée, Emilie ULiege; Haubruge, Eric ULiege; Francis, Frédéric ULiege

Poster (2012, July 26)

A large number of phytoviruses are transmitted exclusively by aphids in a circulative manner after transport by the aphid haemolymph to the salivary glands before transmission to new plant short time ... [more ▼]

A large number of phytoviruses are transmitted exclusively by aphids in a circulative manner after transport by the aphid haemolymph to the salivary glands before transmission to new plant short time later. Some proteins, synthesized in aphids by symbiotic bacteria, are hypothesized to bind to virus particles in the haemolymph, to help transfer inside the aphid without any problem and finally promoting viral transmission efficiency. Multiple endosymbionts commonly coexist in the same host insects. The endosymbiotic bacterial partners of aphids fall into two categories: the obligate “primary” symbiont such as Buchnera sp. found in almost all aphids and the facultative “secondary” bacteria that are not always present. Particular associations between aphids and both Buchnera sp. and secondary symbionts well documented according to adaptation to host plant specificity. In contrast, the impact of specific associations between Buchnera and other facultative secondary endosymbionts on the virus transmission is less well understood. In order to understand the role of some ensymbionts associated to the primary one in the PeMV (Pea enation Mosaic Virus) transmission, several Acyrthosiphon pisum clones presenting different patterns of endosymbionts (Buchnera-Serratia, Buchnera-Spiroplasma, Buchnera-Rickettsia), were used in PeMV efficiency transmission assays on broad bean. The PeMV occurrence in plants was tested by enzyme- linked immunosorbent assay technique (ELISA). The higher virus transmission was found when Serratia bacteria was present in the pea aphid. The occurrence of Serratia endosymbiotic bacteria was concluded to be very important in the PeMV transmission. Finally, the aphid symbiont pattern modulation was discussed in multitrophic approach and potential control of aphid and associated dispersion of viral diseases. [less ▲]

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See detailIdentification of bacteria community associated with earthworm gut
Lemtiri, Aboulkacem ULiege; Alabi, Taofic; Bodson, Bernard ULiege et al

Poster (2012, July 26)

The role of earthworms in soil fertility and transformation of organic waste was regulary cited to be of first importance. Associated to these macro-invertebrates, a large diversity of micro-orgnisms are ... [more ▼]

The role of earthworms in soil fertility and transformation of organic waste was regulary cited to be of first importance. Associated to these macro-invertebrates, a large diversity of micro-orgnisms are found indirectly in their closed environment or directly in their gut. Functional aspects of these interactions and symbiosis in relation with soil characteristics and fertility rates are poorly developed. Here, the micro-organisms diversity and potential related functions of earthworm gut were investigated using a proteiomic approach for both protein and micro-organism identifications. Microbial community investigation was detected by proteomic approach based on bidimensional electrophoresis coupled with mass spectrometry using Matrix Assisted Laser Desorption Ionisation – time of flight (Maldi-Tof). Diversity of gut associated bacterial communities was discussed. Indeed, application of particular crop production practices such as crop residue management at the field level could regulate the gut bacterial communities in earthworm but also microbials in soils. Agricultural systems had to consider the microbial and associated organisms in the soil to enhance fertlility and crop production in sustainable ways. [less ▲]

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See detailA comparison between subjective and objective methods for evaluating the vocal accuracy of a popular song
Larrouy, Pauline ULiege; Lévêque, Yohana; Giovanni, Antoine et al

Poster (2012, July 25)

Vocal accuracy of a sung performance can be evaluated by two methods: acoustical analyses and subjective judgements. For one decade, acoustic analyses have been presented as a more reliable solution to ... [more ▼]

Vocal accuracy of a sung performance can be evaluated by two methods: acoustical analyses and subjective judgements. For one decade, acoustic analyses have been presented as a more reliable solution to evaluate vocal accuracy, avoiding the limitation of experts’ perceptive system and their variability. This paper presents for the first time a direct comparison of these methods. 166 occasional singers were asked to sing the popular song « Happy Birthday ». Acoustic analyses were performed to quantify the pitch interval deviation, the number of contour errors and the number of tonality modulations for each recording. Additionally, eighteen experts in singing voice or music rated the global pitch accuracy of these performances. The results showed a high inter-rater concordance within the judges. In addition, a high correlation occurred between acoustic measurements and subjective rating. The total model of acoustic analyses explained 81% of the variance of the judges’ scores. Their rating was influenced by both tonality modulations and interval deviations. This study highlights the congruence between objective and subjective measurements of vocal accuracy while the assessment is done by music or singing voice experts. Our results confirm the relevance of the “pitch interval deviation” criterion in vocal accuracy assessment. Furthermore, the “number of tonality modulations” is a salient criterion in perceptive rating and should be taken into account in studies using acoustical analyses. [less ▲]

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See detailValidation of ACE-FTS using ground-based FTIR measurements of CFC-11, CFC-12 and HCFC-22
Kolonjari, F.; Mahieu, Emmanuel ULiege; Walker, K.A. et al

Poster (2012, July 24)

Satellite data can be an effective global monitoring tool for long-lived compounds in the atmosphere. The Atmospheric Chemistry Experiment (ACE) is a mission on-board the Canadian satellite SCISAT. The ... [more ▼]

Satellite data can be an effective global monitoring tool for long-lived compounds in the atmosphere. The Atmospheric Chemistry Experiment (ACE) is a mission on-board the Canadian satellite SCISAT. The primary instrument on SCISAT is a high-resolution infrared Fourier Transform Spectrometer (ACE-FTS) which is capable of measuring a wide range of gases including key chlorofluorocarbon (CFC) and hydrochlorofluorocarbon (HCFC) species. These families of species are of interest because of their significant contribution to anthropogenic ozone depletion and to global warming. To assess the quality of data derived from satellite measurements, validation using other data sources is critical. Ground-based Fourier transform infrared spectrometers (FTIRs) are particularly useful for this purpose. In this study, five FTIRs located at four sites around the world are used to validate the CFC- 11, CFC-12, and HCFC-22 data products from ACE-FTS. These species are related; HCFC-22 was the primary replacement for CFC-11 and CFC-12 in refrigerant and propellant applications. The five FTIR instruments used in this study record solar absorption spectra at Eureka, Canada, Jungfraujoch, Switzerland, Poker Flat, USA, and Toronto, Canada. Details on the instrumentation at each site will be provided. The retrieval of CFC-11, CFC-12, and HCFC-22 are not standard products for many of these FTIRs, and as such, the initial stage of this study is to develop the retrieval of each species. Harmonization of retrieval parameters between the sites is an important step in this process. The development of these retrievals and preliminary results will be presented. Additionally, a new method for the validation of ACE-FTS measurements will be discussed. [less ▲]

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See detailLaser cooling of Iron atoms
Huet, Nicolas ULiege; Krins, Stéphanie ULiege; Bastin, Thierry ULiege

Poster (2012, July 24)

We report on the first laser cooling of Iron atoms. Our laser cooling setup makes use of 2 UV laser radiation sent colinearly in a 0.8 m Zeeman slower. One laser is meant for optical pumping of the Iron ... [more ▼]

We report on the first laser cooling of Iron atoms. Our laser cooling setup makes use of 2 UV laser radiation sent colinearly in a 0.8 m Zeeman slower. One laser is meant for optical pumping of the Iron atoms from the ground state to the lowest energy metastable state. The second laser cools down the atoms using a quasi-perfect closed transition from the optical pumped metastable state. The velocity distribution at the exit of the Zeeman slower is obtained from a probe laser crossing the atom beam at an angle of 50 degrees. The fluorescence light is detected using a photomultiplier tube coupled with a boxcar analyzer. The Iron atom beam is produced with a commercial effusion cell working at around 1950 K. Our laser radiations are stabilized using standard saturated-absorption signals in both an Iron hollow cathode absorption cell and an Iodine cell. We will present our experimental setup, as well as the first evidences of cooled down Iron atoms at the exit of the Zeeman slower. [less ▲]

Detailed reference viewed: 25 (8 ULiège)
See detailThe Metagenomic in the Service of the Food Microbiology.
Taminiau, Bernard ULiege; Nezer, Carine; Poullet, Jean-Baptiste et al

Poster (2012, July 23)

Introduction: Food products represent great biotopes for bacteria. The optimisation of foodstuffs conservation, mattering so economically as from the point of view of the public health, pass by a better ... [more ▼]

Introduction: Food products represent great biotopes for bacteria. The optimisation of foodstuffs conservation, mattering so economically as from the point of view of the public health, pass by a better understanding of those biotopes and their spoilage. Microbiologists had already tried to resolve this problem throughout several approaches. Studies based on classical microbiology cultures were completed by strategies centred on approaches independent from the microbiological culture. Purpose: The current techniques of new generation sequencing give a new dimension to the microbial ecology, through the metagenomic analysis of individuals' large number, within a mixed microbial population. Our aim is to demonstrate that this methodology can be successfully applied to the study of foodstuffs microbial flora, and can be adapted to the specific requirements of food microbiology. Methods: This study was carried out on pork's minced meat and white sausage, with shelf-life tests in various conditions of preservation (temperature and packaging). The rDNA 16S was extracted from the original products and samples in the best-before date and, after standardization, hypervariable regions V5 were sequenced. Results: A total about 130.000 sequences were obtained and a metagenomic analysis succeeded in the taxonomic classification to the genus level for 80 % of this population. The subsequent analysis of microbial populations shows that the majority microbial populations at the expiration date are the same ones which are generally observed during microbiological analysis of these meat products. However, the population subdominants and especially several populations of not cultivable germs were able to be identified. These groups of bacteria, more difficult to obtain by the other methods, must be studied because they participate in the spoilage process of food products. Significance: The sensibility of this technology makes possible the analysis of foodstuffs presenting a very low microbial rate and, thus, allows the identification of the microbial contaminants before they grow the levels detected by cultural methods. [less ▲]

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See detailImpact of Myzus persicae infestation on the volatile emission of Arabidopsis thaliana Col-0.
Hien, Truong Thi Dieu ULiege; Delaplace, Pierre ULiege; Francis, Frédéric ULiege et al

Poster (2012, July 22)

Being members of complex communities, plants often emit a wide range of volatile organic compounds to defend themselves against insect invasions. Although many studies exist on insect-induced plant ... [more ▼]

Being members of complex communities, plants often emit a wide range of volatile organic compounds to defend themselves against insect invasions. Although many studies exist on insect-induced plant volatile emission, most of them either compare the influences of various herbivore species on one plant species or the impact of a given herbivore on several host plant species. Moreover, informations related to the influence of insect density as well as the infestation duration are still needed. Here, we showed that a sucking insect – Myzus persicae (green peach aphid) induced the volatile emission from Arabidopsis thaliana Columbia wild-type (A.thaliana Col-0) under laboratory conditions based on results obtained by solid-phase micro-extraction coupled with gas chromatography - mass spectrometry (SPME-GC/MS). The released volatile blend was discussed in relation to related biosynthesis pathways and functions. These included terpenoids, green leaf volatiles, alcohols and isothiocyanate. The qualitative and overall proportion of volatile components differed depended on the number and residence duration of aphids on leaves. By studying the effects of sucking insect stresses to plant, we not only aim to contribute to the fundamental understanding of the emission of volatile components in the interaction between plants and pests, but also to provide standardised and easy to use assays to assess A.thaliana volatile changes according to cross stresses, including both biotic and abiotic ones in ongoing experiments. [less ▲]

Detailed reference viewed: 101 (22 ULiège)
See detailAn effective Real-time Quantitative PCR protocol for quantification of pathogens in foodstuffs
Adolphe, Y.; Crevecoeur, Sébastien ULiege; Duval, P. et al

Poster (2012, July 22)

Detailed reference viewed: 18 (1 ULiège)
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See detailPrevious errorless sequence-learning promotes subsequent SRT performance in patients with Alzheimer's Disease
Schmitz, Xavier ULiege; Bier, Nathalie; Joubert, Sven et al

Poster (2012, July 17)

Motor-learning capacities are known to be relatively preserved in Alzheimer's disease (AD), which is crucial in the context of the patient’s autonomy (e.g., Rouleau et al., 2002). However, it is important ... [more ▼]

Motor-learning capacities are known to be relatively preserved in Alzheimer's disease (AD), which is crucial in the context of the patient’s autonomy (e.g., Rouleau et al., 2002). However, it is important to determine the most appropriate techniques for such learning. In AD, implicit or procedural rehabilitation techniques would be more effective to train new skills than explicit or declarative learning methods (van Halteren-van Tilborg, 2007). Maxwell et al. (2001) showed that reducing errors during motor learning minimizes the building of declarative knowledge and would allow implicit knowledge accumulation. If errorless learning induces the formation of an implicit knowledge, this technique appears to be adapted to the learning of a perceptual-motor skill in patients with impaired controlled processes. Very few studies have investigated errorless learning in procedural learning situations, even though some data suggest that errorless learning would be efficient for learning instrumental activities of daily living (e.g., Thivierge et al., 2008). In this study we examined the acquisition of a new perceptual-motor skill in 12 patients with AD and 12 healthy older adults. We compared the impact of two preliminary sequence learning conditions (errorless vs. errorful) on a serial reaction time (SRT) performance. In SRT, the subject must react as quickly as possible to the appearance of a target on a screen by pressing the key corresponding to the position of the stimulus. The effectiveness of learning is demonstrated by a reaction time improvement when the target follows a repeating sequence. For patients with AD, results confirm that the advantage provided by prior learning occurs only in the errorless condition whereas both learning modes improve SRT performance in healthy participants. In conclusion, these results confirm that the errorless learning promotes the development of implicit knowledge and appears to be an effective method for procedural learning in Alzheimer's disease. [less ▲]

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See detailLearning and Error Reproduction in Alzheimer Disease
Wansard, Murielle ULiege; Erkès, jérôme; Adam, Stéphane ULiege et al

Poster (2012, July 15)

Alzheimer disease (AD) is characterized by an early impairment of explicit memory processes associated to a preservation of implicit memory processes (Fleischman & Gabrieli 1998). Due to the role of ... [more ▼]

Alzheimer disease (AD) is characterized by an early impairment of explicit memory processes associated to a preservation of implicit memory processes (Fleischman & Gabrieli 1998). Due to the role of explicit memory in the suppression of errors during learning, AD patients tend to reproduce automatically (implicitly) errors that occurred during a previous learning (Baddeley & Wilson, 1994). Consequently, errorless learning should be more efficient than a classical “trial-and-error” procedure for AD patients. Indeed, errorless learning decreases the involvement of (impaired) explicit memory by avoiding the interference caused by the production of errors (Bier et al., 2002). The present study investigates the automatic post-learning error production in mild AD patients and matched control subjects by using a word stem completion task (Adam et al., 2005) in conditions of both errorless and trial-and-error learning. Results showed a lower word stem completion performance in mild AD than control subjects, but a similar performance in the patients’ group for the two learning conditions. Moreover, in the trial-and-error procedure, the errors consisted mainly in erroneous responses already produced during the learning phase. In addition, correlation analyses indicate that the ability to suppress errors in the trial-and-error learning condition in mild AD patients is subtended by the efficiency of episodic memory processes, but not by inhibitory abilities. These results suggest that the errorless procedure improves the quality of learning of mild AD patients (production of fewer errors) but do not influence the learning rate per se. [less ▲]

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See detailThe acquisition of new orthographic representations among dyslexic children
Binamé, Florence ULiege; Defraigne, Aurélie; Poncelet, Martine ULiege

Poster (2012, July 14)

Purpose – In developmental dyslexia, spelling deficits have been much less explored than reading deficits, although the former tend to be more persistent than the latter. The aim of this study was to ... [more ▼]

Purpose – In developmental dyslexia, spelling deficits have been much less explored than reading deficits, although the former tend to be more persistent than the latter. The aim of this study was to explore the ability to acquire new orthographic representations through different learning conditions in dyslexic children. Method – Fifteen dyslexic French-speaking children (mean chronological age: 11; 4 years; mean reading age: 7; 6 years), 15 chronological age (CA) and 15 reading age (RA) matched controls participated in the study. Their ability to acquire new orthographic representations was assessed through different learning conditions: isolated pseudowords decoding, text reading with embedded target pseudowords and writing of pseudowords after presentation in their visual form associated or not to a semantic representation. In each condition, ten target pseudowords were presented six times. Orthographic learning was measured by a dictation of the targets immediately after the learning session and one week later. Results – Orthographic learning of dyslexics was significantly impaired and decreased more over time relative to CA group but not to RA group. Otherwise, dyslexics, as other groups, performed better when learning conditions consisted in writing pseudowords than in decoding them. Furthermore the condition associating a semantic representation to the pseudowords did not enhance the performances in any group. Conclusion – These results confirm that decoding abilities are essential to develop orthographic representations and suggest that writing is a powerful learning mechanism in dyslexic as in normal readers. By contrast, a semantic representation seems not to support the development of orthographic representations. [less ▲]

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Peer Reviewed
See detailInversion of multi-temporal geoelectrical field data sets: insights on noise characterization and regularization
Nguyen, Frédéric ULiege; Kemna, Andreas; Robert, Tanguy ULiege et al

Poster (2012, July 11)

Inversion of geoelectrical time-lapse data sets is increasingly growing as monitoring systems are being used in more applications such as seawater intrusion, landslides, remediation of contaminated sites ... [more ▼]

Inversion of geoelectrical time-lapse data sets is increasingly growing as monitoring systems are being used in more applications such as seawater intrusion, landslides, remediation of contaminated sites, landfill operation, shallow geothermal systems, or management of water resources. To date, several inversion strategies exist for taking into account the temporal dimension of the data. The most used nowadays are the independent inversion of multi-temporal data sets, the difference inversion, the temporally-constrained inversion, and the more recent process-based inversion. However, difference inversion schemes generally assume that part of the noise contained in the data cancels out when working with temporal data differences. Temporally-constrained inversion on the other hand assumes that the changes are localized and minor. Process-based inversion requires a more advanced knowledge of the system prior the inversion. In this study we demonstrate that the resolution of the time-lapse inversion scheme is mostly dependent on the quantification of the temporal behavior of the data error, on the resolution of the model-dependent pattern of the survey, and not on the regularization strategy. Our study is based on the imaging results of different data sets with different time and spatial scales, and with different degrees of geological complexity and resistivity contrast, The considered sites are a shallow sandy aquifer and a fractured hard rock aquifer where tracer experiments were performed and monitored using surface arrays. The two studied transport processes are advection, with velocities on the order of 10 m/hour and slower advection/diffusion processes. The strongest improvements were brought by using the data difference and a quantitative estimation of the data error. We found in particular a dependence of the time-lapse data error to the measured resistance (i.e., signal-to-noise-ratio), permitting to formulate an error model to describe the data error present in time-lapse data sets. We used minimum gradient support regularization to invert for model changes with enhanced contrast and found this technique more suited to time-lapse studies than for static images. Noise characterization and error models appear therefore as essential and the most impacting for a successful inversion both for static and time-lapse data whereas different spatio-temporal regularization techniques allowed to decrease artefacts but needs to be coherent with the process. [less ▲]

Detailed reference viewed: 65 (16 ULiège)