References of "Poster"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailWireworms use barley root volatile chemicals to locate their host plant in soil
Barsics, Fanny ULg; Latine, Rémi ULg; Haubruge, Eric ULg et al

Poster (2011, July)

Wireworms (Coleoptera: Elateridae) are soil dwelling pests of many crops. Aldrin and lindane used to provide satisfactory treatment levels of infested lands. Their withdrawal from the market for ... [more ▼]

Wireworms (Coleoptera: Elateridae) are soil dwelling pests of many crops. Aldrin and lindane used to provide satisfactory treatment levels of infested lands. Their withdrawal from the market for environmental issues gave birth to new needs in terms of management. In order to enhance integrated management of this pest, we work on the chemical ecology of Agriotes sordidus Illiger. We focus on its interaction with barley roots, mediated by volatile organic compounds (VOCs). Our experimentations are based on behavioural responses of wireworms in olfactometric devices and their statistical relevance. [less ▲]

Detailed reference viewed: 72 (11 ULg)
Full Text
Peer Reviewed
See detailTwo-level Mixtures of Markov Trees
Schnitzler, François ULg; Wehenkel, Louis ULg

Poster (2011, June 29)

We study algorithms for learning Mixtures of Markov Trees for density estimation. There are two approaches to build such mixtures, which both exploit the interesting scaling properties of Markov Trees. We ... [more ▼]

We study algorithms for learning Mixtures of Markov Trees for density estimation. There are two approaches to build such mixtures, which both exploit the interesting scaling properties of Markov Trees. We investigate whether the maximum likelihood and the variance reduction approaches can be combined together by building a two level Mixture of Markov Trees. Our experiments on synthetic data sets show that this two-level model outperforms the maximum likelihood one. [less ▲]

Detailed reference viewed: 40 (10 ULg)
Peer Reviewed
See detailFASST- a FMRI Artefact rejection and Sleep Scoring Toolbox
Schrouff, Jessica ULg; Leclercq, Yves ULg; Noirhomme, Quentin ULg et al

Poster (2011, June 28)

We started writing the “fMRI artefact rejection and sleep scoring toolbox”, or “FASST”, to process our sleep EEG-fMRI data, that is, the simultaneous recording of electroencephalographic and functional ... [more ▼]

We started writing the “fMRI artefact rejection and sleep scoring toolbox”, or “FASST”, to process our sleep EEG-fMRI data, that is, the simultaneous recording of electroencephalographic and functional magnetic resonance imaging data acquired while a subject is asleep. FAST tackles three crucial issues typical of this kind of data: (1) data manipulation (viewing, comparing, chunking, etc.) of long continuous M/EEG recordings, (2) rejection of the fMRI-induced artefact in the EEG signal, and (3)manual sleep-scoring of the M/EEG recording. Currently, the toolbox can efficiently deal with these issues via a GUI, SPM8 batching system or handwritten script. The tools developed are, of course, also useful for other EEG applications, for example, involving simultaneous EEG-fMRI acquisition, continuous EEG eye-balling, and manipulation. Even though the toolbox was originally devised for EEG data, it will also gracefully handle MEG data without any problem. “FAST” is developed in Matlab as an add-on toolbox for SPM8 and, therefore, internally uses its SPM8-meeg data format. “FAST” is available for free, under the GNU-GPL. [less ▲]

Detailed reference viewed: 30 (2 ULg)
Peer Reviewed
See detailHow do climate warming, plant species richness and plant functional group affect ammonia oxidizing bacteria diversity and function in experimental grasslands?
Malchair, Sandrine ULg; Carnol, Monique ULg

Poster (2011, June 27)

How do climate warming, plant species richness and plant functional group affect ammonia oxidizing bacteria diversity and function in experimental grasslands? Malchair S. and Carnol M. Laboratory of Plant ... [more ▼]

How do climate warming, plant species richness and plant functional group affect ammonia oxidizing bacteria diversity and function in experimental grasslands? Malchair S. and Carnol M. Laboratory of Plant and Microbial Ecology Department of Sciences and Environmental Management University of Liege, Belgium Background: There is increasing evidence of diversity-function relationship and impact of warming for aboveground vegetation. Belowground effects of warming and plant species richness remain however largely unknown, although bacteria regulate many soil processes and some groups, like ammonia oxidizing bacteria (AOB) were, have been suggested highly sensitive to environmental stress. Objectives: 1. Investigation of the response of AOB richness, community composition and function to warming, plant species richness and functional group 2. Exploration of the AOB richness-function link Methods: Soil samples were taken at 2 depths from grassland model ecosystems with different species richness levels (1, 3, 9) and temperature treatments (ambient, ambient+3°C). Selected species belonged to 3 plant functional groups: forbs, legumes and grasses. AOB function: potential nitrification assay (shaken soil slurry method) AOB diversity: polymerase chain reaction followed by denaturing gradient gel electrophoresis (PCR-DGGE) Results: 1. All retrieved AOB sequences were Nitrosospira-like ones 2. Warming had no effect on AOB richness and function 3. Higher plant species richness leads to increased AOB richness and modified community structure. AOB function was increased only at lower depth under warming 4. No difference in AOB richness between the plant functional groups 5. AOB community structure was different and AOB function higher under legumes. 6. The AOB richness-function link was negative under legumes. Conclusions: 1. Plant species influenced AOB richness and community composition. Plant functional group seems to be more important that species richness. 2. Legumes may impact AOB diversity and function through ammonia availability. [less ▲]

Detailed reference viewed: 59 (4 ULg)
Full Text
Peer Reviewed
See detailDecoding Directed Brain Activity in fMRI using Support Vector Machines and Gaussian Processes
Schrouff, Jessica ULg; Kussé, Caroline ULg; Wehenkel, Louis ULg et al

Poster (2011, June 26)

Predicting a particular cognitive state from a specific pattern of fMRI voxel values is still a methodological challenge. Decoding brain activity is usually performed in highly controlled experimental ... [more ▼]

Predicting a particular cognitive state from a specific pattern of fMRI voxel values is still a methodological challenge. Decoding brain activity is usually performed in highly controlled experimental paradigms characterized by a series of distinct states induced by a temporally constrained experimental design. In more realistic conditions, the number, sequence and duration of mental states are unpredictably generated by the individual, resulting in complex and imbalanced fMRI data sets. This study tests the classification of brain activity, acquired on 16 volunteers using fMRI, during mental imagery, a condition in which the number and duration of mental events were not externally imposed but self-generated. To deal with these issues, two classification techniques were considered (Support Vector Machines, SVM, and Gaussian Processes, GP), as well as different feature extraction methods (General Linear Model, GLM and SVM). These techniques were combined in order to identify the procedures leading to the highest accuracy measures. Our results showed that 12 data sets out of 16 could be significantly modeled by either SVM or GP. Model accuracies tended to be related to the degree of imbalance between classes and to task performance of the volunteers. We also conclude that the GP technique tends to be more robust than SVM to model unbalanced data sets. [less ▲]

Detailed reference viewed: 79 (13 ULg)
Full Text
Peer Reviewed
See detailModulating effect of COMT genotype on the brain regions underlying inhibition
Jaspar, Mathieu ULg; Grandjean, Julien ULg; Salmon, Eric ULg et al

Poster (2011, June 26)

Introduction Catechol-O-methytransferase (COMT) is an important enzyme which degrades catecholamines, such dopamine, notably in the prefrontal cortex (Männistö & Kaakkola, 1999). Actually, a transition of ... [more ▼]

Introduction Catechol-O-methytransferase (COMT) is an important enzyme which degrades catecholamines, such dopamine, notably in the prefrontal cortex (Männistö & Kaakkola, 1999). Actually, a transition of guanine to adenine at codon 158 of the COMT gene results in a valine to methionine substitution (Lotta & al., 1995). This phenomenon leads to different COMT genotypes, each associated with a different COMT enzymatic activity (Weinshilboum, & al., 1999). A large number of studies reported an effect of COMT on executive functioning. However, most of them used multi-determined executive tasks (e.g., Barnett & al., 2007). We are interested here to determine the effect of COMT Val158Met genotype on the activity of frontal and parietal areas (Nee & al., 2007; Laird & al., 2005) underlying the specific executive process of inhibition. Methods Procedure In an event-related fMRI experiment, a modified form of the Stroop task was administered to 44 young adults (age range: 18-30) separated into three groups according to their COMT Val158Met genotype: 15 homozygous val/val (VV), 14 homozygous met/met (MM) and 15 heterozygotes val/met (VM) carriers. The Stroop task consisted in the presentation of color words printed in various ink colors (e.g the word blue written in red). Subjects were instructed to name of ink color as fast and accurately as possible by avoiding to read the word. In this version of the Stroop task, three different contexts were created (data not showed here): (1) a congruent context (MC) with a majority of facilitator items (IC), (2) a non-congruent context (MI) with mainly interfering items (II), (3) a neutral context (MN) with mainly neutral items (IN, series of %%% written in different colors). MRI acquisition, data analysis Functional MRI time series were acquired on a 3T head-only scanner operated with the standard transmit-receive quadrature head coil. Multislice T2*-weighted functional images were acquired with a gradient-echo echo-planar imaging sequence using axial slice orientation and covering the whole brain (32 slices, FoV = 220x220 mm², voxel size 3.4x3.4x3 mm³, 30% interslice gap, matrix size 64x64x32, TR = 2130 ms, TE = 40 ms, FA = 90°). Structural images were obtained using a high resolution T1-weighted sequence (3D MDEFT [Deichmann & al., (2004)] ; TR = 7.92 ms, TE = 2.4 ms, TI = 910 ms, FA = 15°, FoV = 256 x 224 x 176 mm³, 1 mm isotropic spatial resolution). Preprocessing and statistical analyses were performed with SPM8 (p<.001 uncorrected). Results Behavioral results indicated the presence of a general interference effect (II – IN items) for reaction time (F(1,41) = 292,44 ; p < 0,001) but no significant difference in interference between the three groups (F(2,41) = 0,27; p = 0,76). FMRI results revealed that interference effect [(MI_II-MI_IN) + (MC_II-MC_IN) + (MN_II-MN_IN)] observed in our three groups is mainly associated with cerebral activity in frontal and parietal areas. Moreover, group comparisons indicates that this effect is associated with increased medial frontal and precentral gyrus activity in VV and VM groups by comparison with MM group, but also in the superior temporal gyrus and in the thalamus in the VM by comparison to MM . Conversely, no supplementary brain area was observed for the comparison of the MM to the two other groups. Conclusions The fronto-parietal brain network associated with interference resolution observed here is consistent with prior reports (Nee & al., 2007; Laird & al., 2005). Moreover, results showed activity in different brain areas according to the COMT genotype. Indeed, a similar behavioral performance is associated to the recruitment of supplementary areas in the carriers of the val allele. This observation, paralleling with the lower COMT enzymatic activity and, thus, the higher cortical dopamine level in met/met individuals, confirms our expectation of a COMT Val158Met genotype modulation of the brain regions underlying inhibition efficiency. [less ▲]

Detailed reference viewed: 51 (8 ULg)
Full Text
Peer Reviewed
See detailThe role of the physioterapist in physical activity promotion
Cloes, Marc ULg; MUGNIER, Benoît ULg; Mouton, Alexandre ULg

Poster (2011, June 25)

This study aimed to understand physiotherapists’ awareness about their physical activity (PA) promoting role and to analyse their actions to promote PA. 185 physiotherapists fulfilled a questionnaire ... [more ▼]

This study aimed to understand physiotherapists’ awareness about their physical activity (PA) promoting role and to analyse their actions to promote PA. 185 physiotherapists fulfilled a questionnaire related to their perceptions of (1) the PA individual motivational determinants, (2) the importance of promoting PA and (3) their actions related to people’s PA promotion. Results show that physiotherapists are aware of their crucial role in PA promotion. Nevertheless, their actions should be more devoted to the prevention and detection of sedentary behaviours. Moreover, connections with other actors of PA promotion should be emphasized in order to respect the principles of an ecological approach. [less ▲]

Detailed reference viewed: 81 (20 ULg)
Full Text
Peer Reviewed
See detailCharacteristics and evolution of hantavirus infection in Liège Area (Belgium)
Krzesinski, Jean-Marie ULg; parotte, Marie-Christine; Vanden velde, Christian

Poster (2011, June 24)

Hantavirus is a zoonosis transmitted by rodents responsible in Europe for Hemorrhagic fever with acute renal syndrome (called nephropathia epidemica or NE). Hantavirus epidemics were increased in the ... [more ▼]

Hantavirus is a zoonosis transmitted by rodents responsible in Europe for Hemorrhagic fever with acute renal syndrome (called nephropathia epidemica or NE). Hantavirus epidemics were increased in the recent years in the South part of Belgium. After acute illness, the question could be about its evolution. [less ▲]

Detailed reference viewed: 11 (0 ULg)
Full Text
Peer Reviewed
See detailPhysiotherapists' representations about physical activity
Mouton, Alexandre ULg; MUGNIER, Benoît ULg; Cloes, Marc ULg

Poster (2011, June 24)

This study aimed to analyze the knowledge and representations of physiotherapists about the physical activity (PA) key concepts. 185 physiotherapists fulfilled a questionnaire related to their knowledge ... [more ▼]

This study aimed to analyze the knowledge and representations of physiotherapists about the physical activity (PA) key concepts. 185 physiotherapists fulfilled a questionnaire related to their knowledge about PA (1) definition, (2) benefits for health, (3) criterion for an effective practice and (4) recommendations. The results shows that the physiotherapists’ knowledge about the key concepts of PA and its implications for PA promotion are surprisingly low. Even if they are aware about the population actual lack of PA practice, their recommendations provided to the public would be inaccurate. Future directions for a more effective action of the physiotherapists as PA promoters are discussed. [less ▲]

Detailed reference viewed: 44 (6 ULg)
Full Text
See detailError distribution estimation in right censored and selection biased location-scale models
Laurent, Géraldine ULg; Heuchenne, Cédric ULg

Poster (2011, June 23)

Suppose the random vector (X;Y) satis es the regression model Y = m(X)+sigma(X)*epsilon where m(X) = E[Y|X] and sigma²(X) = Var[Y|X] are unknown smooth functions and the error epsilon, with unknown ... [more ▼]

Suppose the random vector (X;Y) satis es the regression model Y = m(X)+sigma(X)*epsilon where m(X) = E[Y|X] and sigma²(X) = Var[Y|X] are unknown smooth functions and the error epsilon, with unknown distribution, is independent of the covariate X. The pair (X;Y) is subject to generalized selection biased and the response to right censoring. We construct a new estimator for the cumulative distribution function of the error epsilon, where the estimators of m(.) and sigma²(.) are obtained by extending the conditional estimation methods introduced in de Uña-Alvarez and Iglesias-Perez (2010). The asymptotic properties of the proposed estimator are established. A bootstrap technique is proposed to select the smoothing parameter involved in the procedure. This method is studied via extended simulations and applied to real unemployment data. Reference de UNA-ALVAREZ, J., IGLESIAS-PEREZ, M.C. (2010): Nonparametric estimation of a conditional distribution from length-biased data. Annals of the Institute of Statistical Mathematics, Vol. 62, 323-341. [less ▲]

Detailed reference viewed: 33 (5 ULg)
Full Text
Peer Reviewed
See detailImpurity fingerprints for the identification of counterfeit medicines - a feasibility study
Sacré, Pierre-Yves ULg; deconinck, Eric; Daszykowski, Michal et al

Poster (2011, June 22)

Detailed reference viewed: 24 (3 ULg)
Full Text
See detailThe attachment of Bacillus amyloliquefaciens FZB42 to tomato roots is impaired in a mutant devoid of GalM and PBP4a.
Van der Heiden, Edwige; Jourdan, Emmanuel ULg; Delmarcelle, Michaël ULg et al

Poster (2011, June 20)

In vivo experiments on tomato (Lycopersicon esculentum) roots have been performed: drench of 10-day hydroponic cultures with bacterial suspensions. A second identical treatment was applied one week later ... [more ▼]

In vivo experiments on tomato (Lycopersicon esculentum) roots have been performed: drench of 10-day hydroponic cultures with bacterial suspensions. A second identical treatment was applied one week later and after 30 days of culture, the plants were collected and the bacteria detached from a precise weight of roots were diluted, plated and counted. The mutant devoid of both GalM and PBP4a (encoded by the galM and dacC operon) is affected in its capacity to colonize the tomato roots. [less ▲]

Detailed reference viewed: 101 (8 ULg)
Full Text
Peer Reviewed
See detailHigh Throughput determination of Levonorgestrel in human plasma using a Sensitive LC-MS/MS method
Hubert, Cédric ULg; Streel, Bruno; Sibenaler, Renilde et al

Poster (2011, June 19)

Detailed reference viewed: 255 (20 ULg)
Full Text
See detailReversibly core-cross-linked micelles sensitive to reductive environment for the design of drug delivery systems
Cajot, Sébastien ULg; Danhier, F.; Collodoro, M. et al

Poster (2011, June 16)

Detailed reference viewed: 100 (17 ULg)
See detailThe recent introduction of Lamprichthys tanganicanus in Lake Kivu (Eastern Africa): a threat for the pelagic fishery?
Masilya, Pascal M; Isumbisho, Mwapu; Kaningini, M et al

Poster (2011, June 13)

Detailed reference viewed: 28 (1 ULg)
Full Text
Peer Reviewed
See detailA RAPID UHPLC-DAD-ESI-MSn METHOD FOR ANTHOCYANINS QUANTIFICATION FROM Euterpe oleracea FRUITS HARVESTED AT DIFFERENT TIMES
Dias, A.; Chataigné, G.; Rozet, Eric ULg et al

Poster (2011, June 09)

Euterpe oleracea is a palm tree widely distributed in northern South America. Its greatest occurrence and economic importance happens in the floodplains of the Amazonian delta. The fruits called açai are ... [more ▼]

Euterpe oleracea is a palm tree widely distributed in northern South America. Its greatest occurrence and economic importance happens in the floodplains of the Amazonian delta. The fruits called açai are an interesting source of different anthocyanins. Lately they have gained popularity in North America and in the European countries in the food industry and in the health sector due to their extremely high antioxidant capacity and potential anti-inflammatory activities [1]. Some studies have characterized chemically açaí pulps and have reported anthocyanin profiles which differ both qualitatively and quantitatively. Among other reasons, these differences may be associated with the stages of ripening of the fruits, since açai fruits are generally harvested in different maturation stages. The evaluation of the anthocyanin profile of açai fruits during different maturation stages is thus important for the post-harvest industry. In addition a rapid separation by UHPLC and an unambiguous identification by MSn are very useful for an effective quality control of the fruits. Thus, the aim of this study was to characterize the anthocyanin profiles of açai fruits at different stages of maturity. The fruits were harvested during the peak harvesting season, between July and October 2009, in the floodplains of the eastern Amazonian region (State of Pará, Brazil). A protocol of solid-liquid extraction of phenolic compounds was developed. Characterisation of the anthocyanins present in the fruits of Euterpe oleracea was conducted by UHPLC–DAD–ESI–MSn analysis, in positive ionization mode. All identified compounds was separated in 10 minutes of a total run time of 21 min instead of 55 min in the previously developed HPLC method. Six anthocyanins were identified in the extracts namely: cyaniding-3-glucoside, cyaniding-3-rutinoside, pelargonidin-3-glucoside, peonidin-3-glucoside, peonidin-3-rutinoside and cyanidin. The first two compounds were the major constituents in all maturity stages, with similar proportions, except for the first maturity stage for which the anthocyanins were under the limit of quantification. However, in the last maturity stage, cyanidin-3-glucoside became less abundant than cyanidin-3-rutinoside. On the other hand, cyanidin decreased with maturation. For the other compounds, proportions were similar along maturation. Hence, this work was important as it provides valid information on variation of anthocyanin profiles of açai fruits during maturation. This may contribute to the selection of an optimal maturity stage for harvesting as well as it will allow a rapid quality control of the fruits. [1]: Heinrich, M., et al., Açai (Euterpe oleracea Mart.)- A phytochemical and pharmacological assessment of the species’ health claims. Phytochem. Lett. (2010), doi: 10.1016/j.phytol.2010.11.005 [less ▲]

Detailed reference viewed: 78 (1 ULg)
Full Text
See detailAnalysis of Root Secreted Proteases in Arabidopsis thaliana and Nicotiana tabacum
Désiron, Carole ULg; De Lemos Esteves, Frédéric ULg; Natalis, Lucie et al

Poster (2011, June 09)

Plants are promising tools to produce complex recombinant proteins like antibodies. When host plants are grown on hydroponics, the production of recombinant proteins that are secreted by the roots ... [more ▼]

Plants are promising tools to produce complex recombinant proteins like antibodies. When host plants are grown on hydroponics, the production of recombinant proteins that are secreted by the roots ('rhizosecretion') greatly simplifies harvest and purification of the product, during whole plant life. However, proteases represent up to 10% of the naturally secreted proteins and are known to significantly decrease the yield of production by rhizosecretion. In this study, we analyzed the rhizosecreted proteases of Arabidopsis thaliana and Nicotiana tabacum. Total rhizosecreted proteins were recovered by salt extraction and the protease activity was assayed in vitro or by zymography. The relative contribution of major protease families to total activity was evaluated with specific inhibitors and revealed significant differences between the two species. The degradation capacity of the root-secreted proteases was further characterized against selected target proteins: BSA and human IgGs. [less ▲]

Detailed reference viewed: 93 (31 ULg)
Peer Reviewed
See detailAn integrative model based approach to optimize calcium phosphate scaffold-stem cell combinations
Carlier, Aurélie ULg; Chai, Yoke Chin; Theys, Tina et al

Poster (2011, June 07)

Detailed reference viewed: 12 (1 ULg)
Full Text
Peer Reviewed
See detailDisruption of PDZ protein-protein interactions inhibits Tax transformation and HTLV-1 infection capacities.
Twizere, Jean-Claude ULg; DEWULF, Jean-François; Blibek, Karim ULg et al

Poster (2011, June 06)

Human T-cell leukemia virus type I (HTLV-1) encodes a Tax oncoprotein that is critical for both viral replication and cellular transformation. HTLV-1 Tax possesses a PDZ domain binding motif (PBM) at its ... [more ▼]

Human T-cell leukemia virus type I (HTLV-1) encodes a Tax oncoprotein that is critical for both viral replication and cellular transformation. HTLV-1 Tax possesses a PDZ domain binding motif (PBM) at its C-terminus that is essential for its transforming activity in a Rat-1 model and for IL-2. Tax has been shown to interact with several PDZ domain containing proteins including PSD-95, Beta1-syntrophin, the precursor of interleukin-16, the mammalian homolog of the Drosophila discs large tumor suppressor protein Dlg, PDLIM2, Lin7, hTid1, Tip1, hScrib and MAGI3. In the 15th International Conference on Human Retrovirology: HTLV and Related Retroviruses, we will present a specificity map for the Tax/PDZ domain interactions generated using the human ORFeome 5.1. and we will focus on some of the new Tax/PDZ interactions. [less ▲]

Detailed reference viewed: 49 (20 ULg)
Full Text
Peer Reviewed
See detailNovel drug delivery sytem of siRNA based on chitosan, pegylated chitosan and polyethyleneimine
Ragelle, Héloïse; Vandermeulen, Gaëlle; Riva, Raphaël ULg et al

Poster (2011, June 06)

Detailed reference viewed: 62 (5 ULg)
Full Text
Peer Reviewed
See detailPotentialities of using ASTER & SRTM DEM for road planning in Central African sustainable forest logging context. A case study in East Gabon
Philippart, Julien ULg; Handerek, Daphné ULg; Lejeune, Philippe ULg et al

Poster (2011, June 02)

Slope is the main constraint for sustainable forest road planning in Central Africa. Remote sensing now provides free and downloadable Data Elevation Model (DEM) covering most of appeared lands. In this ... [more ▼]

Slope is the main constraint for sustainable forest road planning in Central Africa. Remote sensing now provides free and downloadable Data Elevation Model (DEM) covering most of appeared lands. In this study, we evaluate potentialities and limitations of Shuttle Radar Topography Mission (SRTM) DEMs, derived from radar interferometry and Advanced Spaceborn Thermal Emission and Reflection Radiometer (ASTER) DEMs, themselves derived from digital photogrammetry for slope evaluation. Assessment is presented for hilly (Milole) and flat (Okondja) areas. Three elevation maps were derived from initial ASTER 30-m and SRTM 90-m DEMs : a SRTM 30-m resampled from SRTM 90-m and two ASTER 30-m where absurd values (artifacts) were corrected with SRTM 90-m and resampled SRTM 30-m respectively. We qualitatively and quantitatively assess the accuracy of all elevation maps compared to 992 (698) slope measures on field along transects of 10.5 (7.5) km in Milolé (Okondja). We estimated root mean square error (RMSE) for slope estimation at 7.8 (10.7), 8.1 (10.1), 11.7 (11.2), 10.1 (11.2) and, 9.3° (11.0°) for SRTM 90-m, SRTM 30-m, ASTER 30-m, ASTER 30-m CORR 90 and ASTER 30-m CORR 30 respectively in Milolé (Okondja). We also use a classification error matrix to assess Global Accuracy (GA) and User’s Accuracy (UA) of elevation maps by classifying ground slopes in two categories: lower or equal and higher than maximum slope limitation of 12% (30%) for primary (secondary) roads. All DEMs show a greater GA in hilly area (Milolé) than in flat area (Okondja) and SRTM derived DEMs show a higher UA for secondary roads constraint. UA for the lower or equal category varies between 55.5 and 75.2% (63.9 and 91.7%) for primary (secondary) roads. The use of corrected aster DEMs increases initial ASTER UA from 0.1 to 18.8% depending on category and slope limitation. Despite a relatively high RMSE for slope grade, all of the DEMs tested were found to be consistent for consideration of maximum slope constraint aiming at sustainable road planning for forest logging in Central Africa. [less ▲]

Detailed reference viewed: 83 (25 ULg)
Full Text
Peer Reviewed
See detailVoice Impact of a Prolonged Reading Task at two Intensity Levels
Remacle, Angélique ULg; FINCK, Camille ULg; Roche, Anne et al

Poster (2011, June 02)

The purpose of this study is to evaluate the impact on voice of both duration and intensity level of 2 hours of continuous oral reading. Fifty normophonic women undergo two sessions of voice loading in ... [more ▼]

The purpose of this study is to evaluate the impact on voice of both duration and intensity level of 2 hours of continuous oral reading. Fifty normophonic women undergo two sessions of voice loading in which the required intensity level of voice varied: 60-65 dB(A) for the first session, and 70-75 dB(A) for the second session. Serial voice quality objective data is obtained every 30 minutes during the oral reading tasks, by use of Multi-Dimensional Voice program (Average fundamental frequency (AvF0), Jitter percent (Jitt), Shimmer percent (Shim), Noise-to-Harmonic Ratio (NHR)). Serial measurements of voice range are also carried out every 30 minutes of the oral reading tasks, by use of the voice range profile. Results indicate that AvF0, lowest frequency of voice range and softest output of phonation rise during prolonged oral reading. On the contrary, Jitt tends to decrease and Shim decreases significantly with the passage of time during the voice loading. NRH does not vary statistically. AvF0 and highest outpout of phonation are the only parameters influenced by the required intensity of oral reading task: they are significantly higher in the 70-75 dB session compared to the 60-65 dB session. [less ▲]

Detailed reference viewed: 46 (12 ULg)
Full Text
See detailSpecific contribution of short-term memory for serial order information to early reading acquisition: A longitudinal study
Martinez Perez, Trecy ULg; Majerus, Steve ULg; Poncelet, Martine ULg

Poster (2011, June 02)

Early reading acquisition skills have been linked to verbal short-term memory (STM) capacity. However, the nature of this relationship remains controversial. Here we distinguished between STM for item and ... [more ▼]

Early reading acquisition skills have been linked to verbal short-term memory (STM) capacity. However, the nature of this relationship remains controversial. Here we distinguished between STM for item and order information based on recent studies showing that STM for order is an important and independent predictor of oral language development. Tasks maximizing STM for serial-order or item information and reading tests were administered to 42 children from kindergarten through 1st grade. Results showed that order STM capacity measured at kindergarten predicted phonological recoding abilities at 1st grade. Implications of poor serial-order STM for reading acquisition in dyslexia are discussed. [less ▲]

Detailed reference viewed: 81 (17 ULg)
Full Text
See detailInfluence of thermoelectric coupling on pacemaker activity generated by mechano-electric feedback in a one-dimensional ring-shaped model of cardiac fiber
Collet, Arnaud ULg; Desaive, Thomas ULg; Pierard, Luc ULg et al

Poster (2011, June 01)

The mechano-electric feedback (MEF) in the heart consists in the influence of the tissue deformations on the cardiac electrical activity. Under certain conditions, tissue deformations can generate ... [more ▼]

The mechano-electric feedback (MEF) in the heart consists in the influence of the tissue deformations on the cardiac electrical activity. Under certain conditions, tissue deformations can generate electrical perturbations via stretch-activated channels, such that the membrane potential can exceed the threshold value needed in order to trigger cardiac action potentials (APs). In the present study, we have developed a one-dimensional ring-shaped model of cardiac fiber taking into account three different couplings: the excitation-contraction coupling (ECC), the MEF and the thermoelectric coupling (TEC). The main goal of this work is to examine the effects of the TEC on the different properties of the pacemaker activity generated by the MEF. [less ▲]

Detailed reference viewed: 50 (16 ULg)
Peer Reviewed
See detailAn easy-to-use pipeline for creating connectomes
Ziegler, Erik ULg; Foret, Ariane; Matarazzo, Luca et al

Poster (2011, June)

Detailed reference viewed: 17 (2 ULg)
See detailTowards the understanding of the structure and assembly of the E. coli septum
Derouaux, Adeline ULg; Vollmer, Waldemar

Poster (2011, June)

Detailed reference viewed: 11 (3 ULg)
Full Text
See detailDefining Antonymy by studying Co-occurrences in Context
Steffens, Marie ULg

Poster (2011, June)

Detailed reference viewed: 13 (0 ULg)
Full Text
See detailModeling post-combustion CO2 capture with amine solvents
Léonard, Grégoire ULg; Heyen, Georges ULg

Poster (2011, June)

Carbon capture and storage is a technology that can contribute to face the challenge of rising energy demand combined with a growing environmental awareness. In the present work, the CO2 capture process ... [more ▼]

Carbon capture and storage is a technology that can contribute to face the challenge of rising energy demand combined with a growing environmental awareness. In the present work, the CO2 capture process with monoethanolamine (MEA) is modeled using the simulation tool Aspen Plus. Two different modeling approaches are studied and compared: the equilibrium and the rate-based approaches. An optimization of key process parameters is performed and process modifications are studied with the objective of improving the global process energy efficiency. [less ▲]

Detailed reference viewed: 46 (1 ULg)
Full Text
See detailA cytokinin route to flowering in Arabidopsis
Bouché, Frédéric ULg; André, Julie ULg; D'Aloia, Maria ULg et al

Poster (2011, June)

Cytokinins (CKs) are involved in many physiological processes. We observed that the application of N6-benzylaminopurine (BAP) to the roots of hydroponically grown plants of Arabidopsis thaliana promotes ... [more ▼]

Cytokinins (CKs) are involved in many physiological processes. We observed that the application of N6-benzylaminopurine (BAP) to the roots of hydroponically grown plants of Arabidopsis thaliana promotes flowering in non-inductive short days. The response to BAP treatment does no require FLOWERING LOCUS T (FT), but activates its paralogue TWIN SISTER OF FT (TSF), as well as FD and SUPPRESSOR OF OVEREXPRESSION OF CO1 (SOC1) (D'Aloia et al., 2011). We present here complementary data obtained with transgenic plants overexpressing a catalytic CK OXIDASE/DEHYDROGENASE (CKX) in the roots. The high efficiency of BAP in promoting flowering in our experimental system contrasts with the variability that emerges from studies gathered in literature. Many factors, either experimental or inherent to plant material, might explain these discrepancies and we are interested in identifying endogenous regulators that might provide a mechanistic explanation. We are therefore investigating whether the endogenous pathways underlying plant developmental phase changes might regulate the relative contribution of CKs to flowering. [less ▲]

Detailed reference viewed: 164 (30 ULg)
Full Text
Peer Reviewed
See detailKynurenic acid is able to suppress cortical spreading depression and the effect size is sex hormone dependent
Chauvel, Virginie ULg; Vamos, Eniko; Pardutz, Arpat et al

Poster (2011, June)

Detailed reference viewed: 19 (5 ULg)
Full Text
Peer Reviewed
See detailCOMPARATIVE STUDY OF SPR BIOSENSORS BASED GOLD AND SILVER COLLOIDAL NANOPARTICLES
Lismont, Marjorie ULg; Dreesen, Laurent ULg

Poster (2011, June)

Noble metal nanoparticles (NPs) can be used as a robust tool for optical bio-sensing. These NPs are known for their strong interactions with light through their surface plasmon resonance (SPR), which ... [more ▼]

Noble metal nanoparticles (NPs) can be used as a robust tool for optical bio-sensing. These NPs are known for their strong interactions with light through their surface plasmon resonance (SPR), which corresponds to the collective oscillations of the conduction electrons on the particles [1]. Among metals, silver and gold NPs are of particular interest not only because they are air-stable but also because their SPR absorption bands are in the visible and near ultra-violet spectral regions, that appear as the most appropriate for technological applications [2]. The first advantage of such optical SPR biosensors is their ability to measure complex formation in real time. Indeed, the SPR absorption spectrum band of the NPs is sensitive to the shape, size, inter-particle distance and composition of the NP as well as the dielectric properties of the surrounding medium [2]. Because of the sensitivity of SPR to the local dielectric environment, plasmonic NPs can act as transducers that convert small changes in the local refractive index and the inter-particle distance into spectral shifts and broadening in the absorption spectra bands [3]. Biotin is a water-soluble B complex vitamin necessary for the production of fatty acids and the metabolism of fats and amino acids. The avidin is a tetrameric protein which can react with biotin to form the strongly bonded biotin-avidin complex.The prototypical biotin-avidin interaction forms the basis of a simple sol-based diagnostic technique for biological analytes. We focused on this well-known couple of bio-molecules to compare optical properties of silver and gold colloidal NPs. Gradual changes with time in the absorption spectra bands of biotinylated 10 nm silver and gold NPs were studied as a function of added avidin. After avidin addition, an increased red-shift of the SPR wavelength and a broadening of the absorption band with time are observed. These changes in the optical properties of colloidal NPs are due to the biomolecular recognition process between biotin and avidin which leads to aggregation of these NPs arising from cross-linking by the tetrameric protein. Moreover, the recognition process induces a variation of the local refractive index around these NPs and thus induces a red-shift of SPR also. The maximum SPR red-shift was reached after 45 minutes and was equal to 25 nm and 15 nm for silver NPs and gold NPs respectively. We concluded that the dielectric sensitivity of gold NPs is smaller than the silver NPs one for a same geometry and for an equivalent concentration of avidin. Therefore, the silver sol is more adapted to detection of avidin than the gold sol. The detection limit, described as the lowest concentration for clear identification of wavelength shift [4] due to biomolecular recognition is determined to be 4 nM for both silver and gold NPs. In this case, the corresponding wavelength shift is about 3 nm. The specificity of the interaction between biocytin and avidin was checked by replacing avidin by BSA. When BSA was added, we observed a SPR shift which was smaller than the detection limit of 3 nm. Future works will be devoted to transpose this kind of biomolecular recognition experiments on gold nanorods in order to improve the dynamic phototherapy efficiency of cancers. [less ▲]

Detailed reference viewed: 207 (25 ULg)
Full Text
See detailDiallyl disulfides: comparison between classical and microwave assisted synthesis
DETHIER, Bérénice ULg; Richel, Aurore ULg; Laurent, Pascal ULg et al

Poster (2011, June)

Garlic contains organosulfur compounds, such as diallyl disulfides (DADS), diallyl monosulfides (DAMS) and diallyl trisulfides (DATS), which have potential health properties. The first objective of this ... [more ▼]

Garlic contains organosulfur compounds, such as diallyl disulfides (DADS), diallyl monosulfides (DAMS) and diallyl trisulfides (DATS), which have potential health properties. The first objective of this work is to conduct the synthesis of these molecules by heating in a classical oil bath or by microwave irradiation with a phase transfer catalyst. We concluded that the synthesis should be cnducted at 40°C in an oil bath, with a phase transfer catalyst. [less ▲]

Detailed reference viewed: 64 (22 ULg)
Full Text
Peer Reviewed
See detailThe perceptual and verbal analogical reasoning in children with specific language impairment (SLI)
Leroy, Sandrine ULg; Guénébaud, Mélanie; Parisse, Christophe et al

Poster (2011, June)

Detailed reference viewed: 53 (6 ULg)
Full Text
See detailTranscriptomic analysis of Arabidopsis roots during floral induction by photoperiod
D'Aloia, Maria ULg; Lamoureux, Thibaut ULg; Tocquin, Pierre ULg et al

Poster (2011, June)

Contribution of the root system to the flowering process remains poorly studied. Part of the problem resides in its difficult isolation from the substrate, especially on adult plants. We used an ... [more ▼]

Contribution of the root system to the flowering process remains poorly studied. Part of the problem resides in its difficult isolation from the substrate, especially on adult plants. We used an hydroponic device that allows synchronous growth and flowering of Arabidopsis and performed global transcript profiling of roots. Samples were harvested during the extension period of a single long day (LD), and in non inductive short day. Microarray data were validated by real-time RT-PCR, and the expression patterns of selected probes were further analyzed in shoots and roots. Some of the genes that were differentially expressed in the roots during the inductive LD did not show the same variations in the shoot, indicating that root transcriptome undergoes specific changes at floral transition. These genes include, for example, GIGANTEA. T-DNA mutants from selected candidate genes are being studied. Both the expression analysis and the reverse genetic approach provide new insights into the contribution of the roots to the flowering process. [less ▲]

Detailed reference viewed: 98 (19 ULg)
Peer Reviewed
See detailEffect of blue monochromatic light on non-visual functions in aging
Daneault, V; Vandewalle, Gilles ULg; Teikari, P et al

Poster (2011, June)

Detailed reference viewed: 13 (1 ULg)
Peer Reviewed
See detailAnt-aphid mutualism - How do ants locate aphid colonies?
Fischer, Christophe ULg; Sablon, Ludovic ULg; Duriaux, Adrien ULg et al

Poster (2011, June)

That some ant species show mutualistic relationships with some aphid species is well known since several decades. Ants protect aphids against natural enemies and as a reward collect the sugar-rich aphid ... [more ▼]

That some ant species show mutualistic relationships with some aphid species is well known since several decades. Ants protect aphids against natural enemies and as a reward collect the sugar-rich aphid excretion called honeydew. However, very little information is available on possible semiochemicals involved in these interactions. This study aims to identify semiochemicals involved in the establishment of this relation, using both chemical and behavioral approaches. Preliminary choice tests confirmed that ant scouts are able to detect aphid colonies at a distance using volatile organic compounds (VOC). Those VOC influencing ant’s orientation may originate from different sources: the attacked plant, the honeydew produced by the aphids and the aphids themselves. VOC emission profiles of each of those potential sources have been established using gas chromatography. Y-olfactometer assay revealed that honeydew volatile compounds are the key element in this distant attraction. Moreover, based on these VOCs, ant scouts are able to discriminate between the honeydew produced by a myrmecophilous and a non myrmecophilous aphid species. Thus, more than just a sugar source, honeydew is an attractant for ant scouts towards myrmecophilous aphids. [less ▲]

Detailed reference viewed: 142 (12 ULg)
See detailMolecular histology for epithelial ovarian cancers biomarker hunting: new issues for biology and pharmacology.
Longuespée, Rémi ULg; Boyon, Charlotte; Kerdraon, Olivier et al

Poster (2011, June)

Detailed reference viewed: 63 (0 ULg)
Full Text
See detailOn generalized Hölder spaces
Kreit, Damien ULg; Nicolay, Samuel ULg

Poster (2011, June)

The Hölder spaces provide a natural way for measuring the smoothness of a function. These spaces appear in different areas such as approximation theory and multifractal analysis and lead to natural ... [more ▼]

The Hölder spaces provide a natural way for measuring the smoothness of a function. These spaces appear in different areas such as approximation theory and multifractal analysis and lead to natural definitions of the notion of fractal function; for example a function belonging to $C^\alpha$ with $\alpha\in (0,1)$ typically has a fractal graph. The purpose of this poster is to present a generalization of such spaces as well as some recent results about their characterizations. [less ▲]

Detailed reference viewed: 130 (20 ULg)
Full Text
See detailStructure-Surface Activity Relationships Of Uronic Acid-Derivative Surfactants From Renewable Resources Applications
Razafindralambo, Hary ULg; Richel, Aurore ULg; Richard, Gaetan ULg et al

Poster (2011, June)

Introduction and Background: Uronic acid-derivative surfactants are amphiphilic compounds with growing interests owing to their potential applications in various areas [1]. This class of carbohydrate ... [more ▼]

Introduction and Background: Uronic acid-derivative surfactants are amphiphilic compounds with growing interests owing to their potential applications in various areas [1]. This class of carbohydrate-based surfactants can be easily prepared from renewable raw materials in a wide range of structure by modular synthesis thanks to the presence of one carboxylic and numerous hydroxyl groups. The polar head group configurations according to the stereochemistry of OH groups, and geometry (cyclic or not), the hydrophobic tail (number and length of alkyl chain), and the type of linker (ester, acetal and amide, etc) are among the main variables in their structural entities. Therefore, the investigation of their structure-surface activity relationships appears valuable for increasing backgrounds, and achieving a rational design for selecting the best structures to be used in different industrial fields [2]. Methodology: A few analogous of glucuronic acid-derivative surfactants have been synthesized by chemical or enzymatic routes. After purification, their structure has been confirmed by various spectroscopic techniques (RMN, MS, IR). Surface tensions of true aqueous solution have been then measured in dynamic and static modes using a series of complementary techniques. Critical micelle concentrations, minimum molecular areas, and maximum surface excesses have also been determined. Results and Discussion: Glucuronic acid derivative surfactants under investigation vary in the polar head group configuration including cyclic or non-cyclic structure and α or β anomeric form, in the hydrophobic tail regarding to the chain length (C8 to C14), the presence of a double bond, as well as an OH group at the terminal carbon, and in the type of linker, ester in C6 or acetal in C1. Results showed that all of these structural attributes affect both dynamic and equilibrium surface properties of glucuronic acid -based surfactants. Conclusion: A set of synthetic glucuronic acid-based surfactants varying in the polar head group, hydrophobic tail, and linker allow us to generate various surface-active properties at the air-water interface, and to increase the knowledge on relationships between their structure and surface-active properties. [1] Laurent, P.; Razafindralambo, H.; Wathelet, B.; Blecker, C.; Wathelet, J.-P.; Paquot, M., Synthesis and Surface-Active Properties of Uronic Amide Derivatives, Surfactants from Renewable Organic Raw Materials. Journal of Surfactants and Detergents 2010, in press. [2] Razafindralambo, H.; Blecker, C.; Mezdour, S.; Deroanne, C.; Crowet, J.; Brasseur, R.; Lins, L.; Paquot, M., Impacts of the Carbonyl Group Location of Ester Bond on Interfacial Properties of Sugar-Based Surfactants: Experimental and Computational Evidences. The Journal of Physical Chemistry B 2009, 113 (26), 8872-8877. Acknowledgment: This work was supported by Belgian Walloon Region within DGTRE research project of excellence (TECHNOSE). [less ▲]

Detailed reference viewed: 163 (26 ULg)
Full Text
See detailFunctional and physicochemical properties of starches isolated from pearl millet landraces grown in hyperarid regions
Boudries, Nadia; Sindic, Marianne ULg; Nadjemi, Boubekeur et al

Poster (2011, May 31)

Detailed reference viewed: 14 (4 ULg)
Full Text
Peer Reviewed
See detailKraft RB : recurrent neural network prediction of steam production
Sainlez, Matthieu ULg; Heyen, Georges ULg

Poster (2011, May 30)

In this study, neural networks approaches are compared for predicting the high pressure (HP) steam flow rate from a Kraft recovery boiler. We apply two types of neural networks: a static multilayer ... [more ▼]

In this study, neural networks approaches are compared for predicting the high pressure (HP) steam flow rate from a Kraft recovery boiler. We apply two types of neural networks: a static multilayer perceptron and a dynamic Elman’s recurrent neural network. Starting from a one-day database of raw process data related to the boiler, the goal is to model and predict the next 12-hours of HP steam flow production from the boiler to the steam turbine. The results illustrate the potential of the dynamic approach in this task. [less ▲]

Detailed reference viewed: 31 (11 ULg)
Full Text
Peer Reviewed
See detailEfficacy of errorless learning in the acquisition of a new procedural skill in Alzheimer's disease
Schmitz, Xavier ULg; Lejeune, Caroline ULg; Vervecken, Nancy et al

Poster (2011, May 27)

In Alzheimer’s disease (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 ... [more ▼]

In Alzheimer’s disease (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). Following Baddeley and Wilson (1994)’s assumption, Maxwell et al. (2001) showed that reducing errors during motor learning minimizes the building of declarative knowledge and would allow implicit knowledge accumulation. However, most studies on errorless learning focused on learning of face-name associations (Clare et al., , 2001), and 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). The aim of this study was to examine the efficacy of an error-reducing versus an errorfull method in motor skill learning. We examined the acquisition of a new motor skill in 24 patients with AD and 24 healthy older adults matched for age, sex, and education. In this task, subjects had to follow with a reversed mouse the contour of a form (a star) displayed on a computer screen. Half the subjects learned in an error-reducing condition, and the others in an errorfull condition. After the learning phase, all the subjects had to complete a novel form. Results show an advantage for the error-reducing condition in the AD group, whereas the performance of the healthy participants did not differ between the two conditions, confirming the efficiency of errorless learning principles in AD for procedural learning situations. [less ▲]

Detailed reference viewed: 92 (11 ULg)
Full Text
See detailLexical and inflectional spelling abilities in French : Same or different ?
Binamé, Florence ULg; Poncelet, Martine ULg

Poster (2011, May 27)

Inflectional spelling abilities have been less extensively studied than lexical spelling abilities and the relationship between these two types of spelling abilities is poorly understood. In this study ... [more ▼]

Inflectional spelling abilities have been less extensively studied than lexical spelling abilities and the relationship between these two types of spelling abilities is poorly understood. In this study, we compared lexical and inflectional spelling abilities in 12-year-old children, by hypothesizing that attentional load may be particularly detrimental for sentence context-dependent inflectional spelling abilities, in contrast to sentence context-independent lexical spelling abilities. Ninety-five sixth graders had to write to dictation sentences containing orthographically inconsistent words as well as inflected words (plural nouns and verbs at the 3th person) in three different cognitive load conditions. In a medium load condition, a time constraint obliged the subjects to write the sentences as quickly as possible. In a high load condition, the participants had to write the sentences as quickly as possible while further carrying out calculation problems (additions). The minimal load condition corresponded to standard writing to dictation, with no time constraint or any secondary task. The number of spelling errors for orthographically inconsistent words (lexical spelling abilities) and inflected words (inflectional spelling abilities) was calculated for each condition. We observed that spelling performance for inconsistent words was not impacted by cognitive load. On the other hand, spelling performance for inflected words decreased significantly in the medium and high load conditions. These results suggest that inflectional spelling abilities are less proceduralized than lexical spelling abilities, and rely to a greater extent on cognitive control processes. [less ▲]

Detailed reference viewed: 57 (16 ULg)
Full Text
See detailEmergency physicians’ communication: What about a standardized handover?
Gillet, Aline ULg; D'ORIO, Vincenzo ULg; Nyssen, Anne-Sophie ULg

Poster (2011, May 27)

In health care organizations, the need for 24-hour care increases the number of patient’s transfer. Handover and shift changes are now recognized as particularly critical moments for the reliability of ... [more ▼]

In health care organizations, the need for 24-hour care increases the number of patient’s transfer. Handover and shift changes are now recognized as particularly critical moments for the reliability of care. However, few studies focused specifically on how physicians share relevant information during these moments. Moreover, emergency departments are known to be extremely vulnerable to error, because of high time pressure, frequent interruptions, high variability and number of patients, etc. Our study aimed to estimate how emergency physicians share information about a patient during handover, and to evaluate the impact of a procedure of medical handover standardization. To do this, we conducted a pre-post test on completeness of transmissions. We first performed observations of 50 physicians’ shift changes in an emergency department. All of these were video-recorded and then analyzed. We classified communications into seven categories (identifying information, current pathology, patient’s current status, significant patient’s tests results, priority medical interventions, diagnose and recommendations, and dispositions). After these observations, we elaborated and implemented a standardization procedure, according to literature, analyses of our observations and physicians’ recommendations. We finally assessed this procedure by observing and analyzing 40 handovers, using the same method as previously described. We also evaluated the physician’s opinion about the quality of the transmission with a 7-point Likert scale. Our results showed three significant differences before and after the standardization of communications. Physicians share more information about patient’s tests results, priority interventions and dispositions. Moreover, we found a significant difference of the perceived quality of the standardized handover. [less ▲]

Detailed reference viewed: 70 (14 ULg)
Peer Reviewed
See detailDevelopmental differences in the procedural learning of a perceptual-motor skill
Lejeune, Caroline ULg; Catale, Corinne ULg; Merbah, Sarah ULg et al

Poster (2011, May 27)

It is generally admitted that procedural learning is efficient early in childhood. However, few studies have brought empirical data confirming this assumption, and many questions remain regarding the ... [more ▼]

It is generally admitted that procedural learning is efficient early in childhood. However, few studies have brought empirical data confirming this assumption, and many questions remain regarding the cognitive mechanisms that sustain procedural learning in children. The aim of our study was to investigate whether perceptual-motor procedural learning was present to the same extent in 7-, 10-year-old children and in adults. We also examined the role of executive functions, working memory, general intelligence, and motor ability during the learning process. A total of 76 subjects divided into 3 age-groups were tested. The task included 4 blocks of 3 trials during which each subject had to trace the contour of a triangle with an inverted computer mouse. Analyses show an important difference between groups in the initial phase of the learning process. They also reveal that executive functions intervene during the first learning phase, which might explain the observed age effect. In addition, results show significant but different learning effects for the procedural task: while the improvement was equivalent between 10-year-olds and adults, 7-year-old children showed a greater learning slope than the other groups; despite their slowness during the first blocks, younger children showed an equivalent performance at the end of the learning phase. These results suggest that, if executive processes are important during the first learning steps, they are not a “necessary condition” for motor skill learning to occur. The role of compensatory strategies sustaining learning in younger children is discussed. [less ▲]

Detailed reference viewed: 37 (4 ULg)
Full Text
Peer Reviewed
See detailChildren and parents: The anxiety sensitivity, what links?
Stassart, Céline ULg; Etienne, Anne-Marie ULg

Poster (2011, May 27)

Objectives. Anxiety sensitivity (AS) is the fear of anxiety-related sensations. This work examines the relationships between childhood learning experiences and the development of AS, in a non-clinical ... [more ▼]

Objectives. Anxiety sensitivity (AS) is the fear of anxiety-related sensations. This work examines the relationships between childhood learning experiences and the development of AS, in a non-clinical sample of children. Methods. Seventy normal children aged 9 to 12 years were interviewed about their learning experiences with anxiety-related and cold-related somatic symptoms. Three learning status were examined: -reinforcement, verbal transmission and observational (mother and father) learning- using the Questionnaire d'Expérience d'Apprentissage (QEA). AS levels were assessed using the Childhood Anxiety Sensitivity Index (CASI). Results. Correlations between QEA and CASI (r between 0.31 and 0.60, p<0.01) are significant, except for the reinforcement of somatic symptoms in learning by observation of the father. For boys, all learning experiences correlate with CASI scores (r between 0.33 and 0.62, p<0.001), except the reinforcement in learning by observation of the father. For girls, two correlations are observed: for verbal transmission learning following anxiety (r = 0.57) and cold (r = 0.55) symptoms (p=0.001). The level of AS correlate with learning by observation of the father only for boys (r=0.38, p<0.05). Conclusions. These results could suggest that learning experiences seem to play a significant role in the development of AS and suggest also a gender transmission: between different status of learning for boys and girls and between the observation of the mother and the father. Learning by observation of the father will only be linked to boy's AS. These findings bring to question the specific impact of a father's fears in the development of children's AS. [less ▲]

Detailed reference viewed: 74 (5 ULg)
Peer Reviewed
See detailThe "other-age" effect in age estimation of faces
Moyse, Evelyne ULg; Manard, Marine ULg; Brédart, Serge ULg

Poster (2011, May 27)

In this study the occurrence of an “other-age” effect on age estimation was assessed. This effect consists in a more accurate estimation of own-age faces than other-age faces. Here, the age of ... [more ▼]

In this study the occurrence of an “other-age” effect on age estimation was assessed. This effect consists in a more accurate estimation of own-age faces than other-age faces. Here, the age of participants (10 to 14 year old children and 20 to 30 year old adults) and the age of stimuli (faces of 10 to 14 year old children and faces of 20 to 30 year old adults) were crossed. Although we did not observe a crossed interaction where each age group would have been more accurate for in-group estimation than for out-group estimation, present results revealed the occurrence of an own-age bias in age estimation. Although both groups did not differ when estimating child faces, adults were more accurate than children when estimating the age of adult faces. Therefore, the present results showed an asymmetrical "other-age" effect. Several hypotheses explaining the present pattern of results are discussed. [less ▲]

Detailed reference viewed: 96 (16 ULg)
Peer Reviewed
See detailPsychology of migration and losses: Mourning process in families native from Democratic Republic of Congo
Thiltges, Esther ULg; D'Amore, Salvatore ULg; Blavier, Adelaïde ULg

Poster (2011, May 27)

Migration constitutes a potentially traumatic event along with cultural losses and psychic reorganizations (Moro, 1994, 1998). The lost object is physically absent but psychologically present and this ... [more ▼]

Migration constitutes a potentially traumatic event along with cultural losses and psychic reorganizations (Moro, 1994, 1998). The lost object is physically absent but psychologically present and this ambiguity precludes the mourning process (Boss, 1999). Indeed migration losses are unclear, incomplete and potentially retrievable (ex: return in the country, Falicov, 2003). The mourning process cannot be achieved because the object (country, family, cultural and social environments) is still existing (Aouattah, 2003). Nevertheless, exile does not have to be seen only as traumatizing but also as a potentially creative experience (Douville, 2001). Therefore, we also took into account benefits of the migration and individual resources. We analyzed a sample of five families from the Democratic Republic of Congo – with open questions during two meetings – and we tested the following hypothesis: "the mourning process is the result of the dynamic interactions between losses, resources and benefits ". We defined these dynamics through three steps: association and confusion; dissociation and identification; integration and achievement of the mourning process. We tested our hypothesis using Alceste – which is a statistical tool for discourse analysis – and the results confirmed it. We can state our conclusions as follows. At the first stage of the process, there exists confusion between losses, resources and benefits. At the second stage, the persons can differentiate and separate these three elements. And at the last step, people can achieve the mourning process, live with their losses and launch themselves into the future. [less ▲]

Detailed reference viewed: 91 (11 ULg)
Full Text
See detailThe importance of short-term memory for order in dissociating short-term memory and language deficits
Attout, Lucie ULg; VAN DER KAA, Marie-Anne ULg; GEORGE, Mercédès ULg et al

Poster (2011, May 27)

Selective verbal short-term memory (STM) deficits are rare, and when they appear, they are often associated with a history of aphasia, raising doubts about the selectivity of these deficits. We explore ... [more ▼]

Selective verbal short-term memory (STM) deficits are rare, and when they appear, they are often associated with a history of aphasia, raising doubts about the selectivity of these deficits. We explore here the distinction between STM for item information and STM for order information to separate STM and language impairments. Recent models of STM consider that STM for item information depends upon activation of the language system, and hence item STM deficits should be associated with language impairment. By contrast, STM for order information is considered to recruit a specific system, distinct from the language system. In this view, order STM should be impaired in patients with STM deficits that cannot be accounted for by language impairment. We applied this rationale to the exploration of STM profiles of patients MB and CG. Patient MB showed mild phonological impairment and associated STM deficits. As predicted, these were characterized by poor item STM but preserved order STM. Patient CG showed verbal STM deficits with no associated language deficits. His STM deficit was characterized by poor order STM but relatively preserved item STM. This study presents the first double dissociation between item and order STM deficits, demonstrating the necessity of this distinction for understanding selective STM impairment. [less ▲]

Detailed reference viewed: 77 (13 ULg)
Full Text
Peer Reviewed
See detailImpact of visual modality on acoustic assessment of rooms
Defays, Aurore ULg; Safin, Stéphane ULg; Billon, Alexis ULg et al

Poster (2011, May 27)

In the context of the conception of a multimodal immersive environment aimed to support the task of assessing the acoustical quality of rooms based on numerical simulations, we study the relationship ... [more ▼]

In the context of the conception of a multimodal immersive environment aimed to support the task of assessing the acoustical quality of rooms based on numerical simulations, we study the relationship between image and sound. Auralias project aims to develop an immersive environment for a collaborative work between architects and acousticians combining 3D sound rendering and 3D view of the room model. In this study, we analyzed the impact of a room picture on the acoustic assessment. We chose reverberation as acoustic parameter. First, we confronted 70 subjects with a sound clip and asked them to assess the reverberation degree (control condition). Then, we divided the subjects into three groups and repeated the same judgment task. However, in the first group, subjects listening the sound clip were confronted with a room picture consistent with the sound. In the second group, they were confronted with a « distractor » room picture (no link with the sound). In the last group, they listened the sound clip without any room picture. Our results showed a positive impact of consistent pictures on reverberation assessment but we found no effect of distractor pictures. [less ▲]

Detailed reference viewed: 53 (7 ULg)
Peer Reviewed
See detailReactive Attachment Disorder and socio-emotional development in childhood: Clinical review.
Wertz, Céline ULg; Gauthier, Jean-Marie ULg; Blavier, Adelaïde ULg

Poster (2011, May 27)

The quality of interactions experienced with primary attachment figures influence the development of emotional skills. On the other hand, we know how emotions fill a critical adaptive role for the social ... [more ▼]

The quality of interactions experienced with primary attachment figures influence the development of emotional skills. On the other hand, we know how emotions fill a critical adaptive role for the social adjustment, in that they assume both a communicative function and an informative value. In this research, we were particularly interested in how children’s patterns of attachment were expressed in terms of emotional regulation abilities. According to Laible & Thompson’s observations (1998), we tested the following hypothesis: insecure attachment representations are associated with a poverty of skills in decoding emotional signals. They especially would affect the perception of negative emotional expressions. We tested this hypothesis by the meeting of five children of primary school age (5 to 8 years old) with a reactive attachment disorder and through the establishment of two methodological tools. At first, the Attachment Story Completion Task (Bretherton et al., 1990) allowed us to identify attachment representations for each child. Secondly, inspired by Pollak & al.’s study, we developed a recognition task of facial emotional expressions. We observed in these children low average rates of identification of basic and primary emotions. Especially, the accuracy of judgments was not only a function of emotion’s valence, but was also dependant of the child’s attachment pattern. Finally, this research confirmed the observations, already showed in previous studies, that interpersonal difficulties presented by these children could be explained specifically by their inefficiency in interpreting social cues surrounding emotional events (Crick & Dodge, 1994). [less ▲]

Detailed reference viewed: 234 (34 ULg)
Full Text
Peer Reviewed
See detailRelations between a computerized shopping task and cognitive and clinical variables in patients diagnosed with bipolar disorder and alcohol dependency compared with healthy controls.
Laloyaux, Julien ULg; Michel, Céline; Pellegrini, Nadia et al

Poster (2011, May 27)

Persons diagnosed with bipolar disorder and alcohol dependency are frequently subject to poor everyday life functioning. However, previous studies have primarily used questionnaires or observational ... [more ▼]

Persons diagnosed with bipolar disorder and alcohol dependency are frequently subject to poor everyday life functioning. However, previous studies have primarily used questionnaires or observational methods to assess everyday life functioning, both of which contain a number of limits. In order to address some of these limits, we developed a computerised real-life activity task, in particular, a shopping task where participants are required to shop for a list of 8 grocery store items. Twenty individuals diagnosed with alcoholic dependence and 21 patients diagnosed with bipolar disorder were compared with 20 and 21 matched healthy controls, respectively. All participants completed the shopping task, and both clinical groups were evaluated with an extensive battery of neuropsychological tests and a measure of global functioning. Results showed that, for both clinical groups, performance on the computerised shopping task significantly differentiated patients and healthy controls for a number of variables, especially total time and mean time to consult the shopping list. Performances on shopping task variables, in both clinical groups, were also significantly correlated with neuropsychological tests measuring verbal episodic memory, processing speed and selective attention. Finally, performances on the computerised shopping task were significantly correlated with various clinical variables and with global functioning in both patient groups. These findings suggest that the computerised task used in the present study provides a valid indication of the level of everyday life functioning for these clinical populations, and therefore may be viewed as a valuable instrument in both an evaluation and remediation context. [less ▲]

Detailed reference viewed: 74 (15 ULg)
Peer Reviewed
See detailHow conditioning by one’s job leads to visual misrepresentation: Evidence from Rorschach test in nurse population
Englebert, Jérôme ULg; Blavier, Adelaïde ULg

Poster (2011, May 27)

Exner (1974, 2003, 2005) has developed an empirical method for analyzing answers at Rorschach test. This analysis is not focused on the answer content but more on perception, information processing and ... [more ▼]

Exner (1974, 2003, 2005) has developed an empirical method for analyzing answers at Rorschach test. This analysis is not focused on the answer content but more on perception, information processing and quality of the answer. Thus, contrary to psychoanalysis, the content and its interpretation are not systematically studied in this empirical approach. In this perspective, our purpose was to empirically study how answers and performance at Rorschach test were conditioning by one’s job. We administrated Rorschach test to 38 nurses and 38 paired subjects (matched for gender and age). Our data showed nurses gave significantly more anatomical answers than control subjects, this first result confirmed a clinical assumption that was never objectified by previous studies: conditioning by one’s job influences the answer content at the Rorschach test (e.g., people from medical sector tend to see organs). The second main result is the formal qualities of anatomical answers given by nurses were significantly worse and more unusual than anatomical answers given by the control group. These findings suggest that conditioning by one’s job is so strong that it overrides the other choices of answers and can lead to a deformation of the visual perception. Furthermore, the content is the main answer element subjects can control in this test and thus, it could be a means of affirming his/her identity (e.g., nurse’s identity by anatomical content). Moreover, in regard to the bad formal quality of anatomical answers, it seems that nurse’s identity takes precedence over the reality and the actual form perception. [less ▲]

Detailed reference viewed: 47 (11 ULg)
Peer Reviewed
See detailOpinions and practice of forensic psychologists about credibility assessment
Beerten, Jérôme ULg; Blavier, Adelaïde ULg

Poster (2011, May 27)

Assessing victim’s credibility is essential but very complex when physical evidence is lacking. The dual query of evaluating victim’s credibility and sequels and unclear mandates increase the confusion ... [more ▼]

Assessing victim’s credibility is essential but very complex when physical evidence is lacking. The dual query of evaluating victim’s credibility and sequels and unclear mandates increase the confusion. Similarly, the use of the controversial term “credibility” illustrates the different expectations of the various protagonists involved in the judicial process. The conditions of evaluation and the limitations of available methods and assessment tools make this task difficult for the forensic psychologists. In this context, our exploratory study aimed to understand how forensic psychologists actually performed their task. In 2007, we interviewed 11 forensic psychologists with a questionnaire on their training, their practice, their use of the different methods of assessment, their understanding of the concept of credibility, their perception of their role and the content of their forensic report. Different practices were observed, although a majority of forensic psychologists used the Statement Validity Analysis (SVA) and seemed to use the assessment tools within the limits of their duties. Despite the use of scientifically-validated tools, they gave a great attention and value to nonverbal behaviors and symptoms in their evaluation. Moreover, 5/11 forensic psychologists considered transmission of data about the reality and/or truth of the facts was an integral part of their mission. Another sample of 16 forensic reports we analyzed in parallel showed under-utilization of scientifically valid assessment tools of suggestibility and an overuse of SVA elements (e.g., without video-tape-recording). In conclusion, forensic psychologists seemed to support their conclusions more on a range of consistent elements than on scientifically-based salient information. [less ▲]

Detailed reference viewed: 73 (8 ULg)
Full Text
See detailQuantification and monitoring of contaminant mass fluxes in heterogeneous subsurface media
Jamin, Pierre ULg; Brouyère, Serge ULg

Poster (2011, May 26)

Since the beginning of the years 2000, a consensus has been growing among the scientific, technical and decision makers community concerning the fact that the characterisation and the management of ... [more ▼]

Since the beginning of the years 2000, a consensus has been growing among the scientific, technical and decision makers community concerning the fact that the characterisation and the management of contaminated sites have to be performed in terms of contaminant flux metrics instead of to be based on a simplistic study of pollutant concentration coming from piezometers randomly spread over the site. Contaminant plumes and associated pollutant mass fluxes are extremely variable in space as well as in time. The scientific and technical challenge is to capture this double heterogeneity in order to consider it explicitly or statistically for the management of a contamination issue. This requires (1) the interception of the entire contaminated groundwater flowing section with a control panel; (2) the ability to measure and to calculate accurately groundwater and contaminant fluxes across that panel; and (3) the repetition of the measurement to bring out the spatial and the temporal variation of contaminant fluxes. This research project aims to develop an integrated pollutant flux measurement approach for contaminated groundwater at the scale of the contaminant plume. This approach lays on a triple integration of (1) single well tracing techniques – (2) passive sampling – (3) control panel. Spatial and temporal variability of groundwater fluxes will be quantified by the point dilution tracing method derived from the “FVPDM” technique (Brouyère et al. 2008). In the same time, the amount of pollutant flowing through the same location will be determined by the adequate passive sampling technique (PS). The integration of these two measures in an interpretation schema based on mathematical and numerical modelling will allow quantifying contaminant fluxes and their variability over time. The adaptation at the scale of the contaminant plume will be based on a logging-type use of techniques, repeated along the vertical axis of the monitoring wells and repeated from one well to an other of a control panel implanted to intercept the plume. All the research results and developed techniques will then be integrated into a complete measurement system (PS-FVPDM), mobile and easily usable on field. The whole development and testing will take place on several pilot contaminated test site located in various hydrogeological context. [less ▲]

Detailed reference viewed: 47 (4 ULg)
Full Text
Peer Reviewed
See detailPerformance of leaf wetness sensor used in winter wheat disease management
Mahtour, Abdeslam ULg; El Jarroudi, Moussa ULg; Hoffmann, Lucien et al

Poster (2011, May 26)

Wetness on crop leaves has particular epidemiological significance because many fungal diseases affect plants only when free moisture is present on leaves. The leaf wetness sensor detects the presence of ... [more ▼]

Wetness on crop leaves has particular epidemiological significance because many fungal diseases affect plants only when free moisture is present on leaves. The leaf wetness sensor detects the presence of wetness on a leaf’s surface, enabling researchers and producers to forecast disease and protect plant canopies, and consequently to optimize fungicide application and often reduce environmental load. This research project aimed at better understanding the leaf wetness duration and its influence in winter wheat disease. Measurement of surface wetness duration by three electronic flat-plate sensors (Model 237-Campbell Scientific, Inc) in wheat fields were compared with tactile and visual observations in replicated field experiments at the site of Arlon (Belgium) during the period May-July 2006 and April-July 2007. Performances of the sensor were evaluated against SWEB model outputs and visual observations of disease symptoms. On the field, dew-onset and dry-off of wetness on leaves were observed visually (with a flash light for dew-onset) at 15-minute intervals. Each sensor was placed close the flag leaf. For the three sensors, the two dew-onset and dry-off times measured in both 2006 and 2007 crop seasons gave a leaf wetness duration (LWD) which was on average one hour less than visual observations. In order to establish a relationship between the surface wetness periods and wheat foliar diseases, LWD was compared with the Septoria leaf blotch (SLB) development risk (main winter wheat disease). A minimal surface wetness duration favourable to infection for SLB was established. [less ▲]

Detailed reference viewed: 87 (5 ULg)
Full Text
See detailPrevalence and screening of burnout among Belgian population
DE CIA, Julie ULg; Mairiaux, Philippe ULg; Schippers, Nathalie ULg et al

Poster (2011, May 26)

The aim of the study was to estimate the prevalence of burnout among Belgian workers through the identification of burnout cases within the practices of general practitioners (GP) and the health ... [more ▼]

The aim of the study was to estimate the prevalence of burnout among Belgian workers through the identification of burnout cases within the practices of general practitioners (GP) and the health surveillance carried out by occupational health physicians (OP) .The prevalence may be estimated at about 0,8 % of the Belgian population; this figure is similar among workers consulting GP and OP. [less ▲]

Detailed reference viewed: 96 (26 ULg)
Peer Reviewed
See detailCompetency Model validation process : an illustration in public administration sector
Lothe, Benoit ULg; Hansez, Isabelle ULg; Bertrand, Françoise ULg

Poster (2011, May 26)

Background: Nowadays Human Resource Management issues are highly related to the strategic approach (Analoui, 2007; Daft, 2008; Becker, Huselid & Beatty, 2009 ; Jackson, Schuler & Werner, 2009). Workforce ... [more ▼]

Background: Nowadays Human Resource Management issues are highly related to the strategic approach (Analoui, 2007; Daft, 2008; Becker, Huselid & Beatty, 2009 ; Jackson, Schuler & Werner, 2009). Workforce is considered as an asset and HRM is required to match human capital with organization strategic purposes. HRM practices have accordingly evolved to better fulfil this requirement through for instance Competency Modelling (CM) (Werbel & De Marie, 2005). Diagnosis: This communication illustrates a specific CM validation process in a wide Public Administration. Through a “one-size-fits-all” competency model approach (Mansfield, 1996), the HRM department of this Public Administration has developed a set of 29 transverse competencies broken down across 290 behavioural indicators. After several in-house pre-validation steps (workshops and test cases), Human Resources Development Unit of University of Liege was invited to collaborate to the final validation process. Solution: Based on Van Beirendonck (2006) CM validation criteria, a two steps validation method was jointly developed. Four main criteria were used, therefore each behavioural indicator ought to : (1) meet various organizational departments needs; (2) be clearly understood within the organization (Bowen & Ostroff, 2004); (3) have a straight link with its belonging competency and (4) be observable. A questionnaire survey (n=252) was drawn up to appraise the first three criteria and quantitative analysis results provided the CM improvement framework. The concluding validation stage assessed the three last criteria by measuring Subject Matter Experts (HR managers responsible for staff evaluation) interrater agreement in order to improve CM content validity (Sanchez & Levine, 2009). Finding: Results comfortably confirm CM content validation under the four criteria. One of the project’s more relevant elements is developing a scientifically based method adapted to wide administration organizational features and constraints. In contrast, this CM validation project presents some limitations in relation to the CM theoretical concept (ambiguous concept in its validation perspective) and to organizational constraints (lack of strategic project concerning the use of the CM). Method and outcomes will be discussed in connection with the customer’s requirements and the constraints from the organizational context. [less ▲]

Detailed reference viewed: 164 (3 ULg)
Full Text
See detailMultiqubit symmetric states with a high geometric entanglement
Martin, John ULg; Giraud, Olivier; Braun, Peter et al

Poster (2011, May 25)

We propose a detailed study of the geometric entanglement properties of pure symmetric N-qubit states, focusing more particularly on the identification of symmetric states with a high geometric ... [more ▼]

We propose a detailed study of the geometric entanglement properties of pure symmetric N-qubit states, focusing more particularly on the identification of symmetric states with a high geometric entanglement and how their entanglement behaves asymptotically for large N. We show that much higher geometric entanglement with improved asymptotical behavior can be obtained in comparison with the highly entangled balanced Dicke states studied previously. We also derive an upper bound for the geometric measure of entanglement of symmetric states. The connection with the quantumness of a state is discussed. [less ▲]

Detailed reference viewed: 49 (10 ULg)
See detailComparative study of gold and silver based nanobiosensors
Lismont, Marjorie ULg; Dreesen, Laurent ULg

Poster (2011, May 25)

Due to their particular optical properties, resulting from the surface plasmon resonance (SPR) phenomenon, silver and gold nanoparticles (NPs) can be used as robust tools for optical biosensing [1 ... [more ▼]

Due to their particular optical properties, resulting from the surface plasmon resonance (SPR) phenomenon, silver and gold nanoparticles (NPs) can be used as robust tools for optical biosensing [1]. Optical SPR biosensors are able to measure complex formation in real time. Indeed, the SPR absorption spectrum band of the NPs is sensitive to the shape, size, inter-particle distance and composition of the NP as well as the dielectric properties of the surrounding medium [2]. Due to the sensitivity of SPR to the local dielectric environment, plasmonic NPs can act as transducers that convert small changes in the local refractive index and the inter-particle distance into spectral shifts and broadening in the absorption spectra bands [3]. In our study, the prototypical biocytin-avidin interaction was used to study gradual changes with time in the absorption spectra bands of biotinylated 10 nm silver and gold NPs as a function of added avidin. After avidin addition, a SPR red-shift and a broadening of the SPR bands were observed with both NPs. These optical changes evolved with time and reached their final values after around 45 min for each system. The maximum SPR red-shifts were equal to 25 nm and 15 nm for silver NPs and gold NPs, respectively. The detection limit, described as the lowest concentration for clear identification of wavelength shift due to biomolecular recognition, is determined to be 4 nM for both silver and gold NPs. The specificity of the biocytin-avidin biosensors was checked by replacing avidin by BSA. When BSA was added, we observed a SPR band shift which was smaller than the detection limit of 3 nm, attesting the biosensor selectivity. Our work demonstrates the superiority of Ag over Au NPs for the elaboration of biosensors based on SPR. [less ▲]

Detailed reference viewed: 50 (2 ULg)
Full Text
Peer Reviewed
See detailField evaluation of survival rates of Harmonia axyridis (Coleoptera: Coccinellidae) and other aphidophagous species
Vandereycken, Axel ULg; Durieux, Delphine ULg; Joie, Emilie ULg et al

Poster (2011, May 24)

The multicoloured Asian ladybird Harmonia axyridis Pallas (Coleoptera: Coccinellidae), previously introduced as a biological control agent against aphids, is now frequently considered as an intraguild ... [more ▼]

The multicoloured Asian ladybird Harmonia axyridis Pallas (Coleoptera: Coccinellidae), previously introduced as a biological control agent against aphids, is now frequently considered as an intraguild predator, consuming other aphids natural enemies. Interactions between this exotic ladybird and the other aphidophagous species present in Belgian agro-ecosystems such as Coccinella septempunctata, Episyrphus balteatus, Chrysoperla carnea are asymmetric to the benefit of H. axyridis. Many studies have already shown its predatory behaviour. This study focuses on the survival rate of three aphidophagous species Harmonia axyridis (Ha), Coccinella septempunctata (C7) and Episyrphus balteatus (Eb) in biological fields of potato and sugar beet. During June and July, hermetic cages were disposed on the crops with 10 larvae (second stage) of each aphidophagous. There were 4 combinations of insects placed inside the cages (1) Ha+Eb+C7+ aphids, (2) Ha+Eb+C7, (3) Eb+C7+ aphids and (4) Eb+C7. Each combination was repeated three times. Aphids (Aphis fabae) were added in excess when needed. In sugar beet fields, E. balteatus was the species with the highest mortality rate. The two coccinellid species had a better survival rate than E. balteatus. All aphidophagous species had higher mortality rates in absence of aphids. In potato, the survival rate of all aphidophagous was lower than sugar beet when aphids were present in excess probably because A. fabae reproduced less in potato. Nevertheless, we have observed in potato no mortality of C. 7-punctata during all its development cycle. This suggests that C. 7-punctata could use more efficiently aphids as food sources than H. axyridis. In potato and sugar beet, H. axyridis had the longest development cycle, being still at the larval stage when C. 7-punctata and E. balteatus reached the pupae stage. We can suppose that pupae of E. balteatus and C. 7-punctata were an alternative food (intraguild prey) to H. axyridis when aphids were lacking. Pupae are immobile and therefore more sensitive to the attack of predators. [less ▲]

Detailed reference viewed: 108 (21 ULg)
Full Text
See detailPredominant effects of host plant species on Aphis gossypii aphid and Episyrphus balteatus hoverfly in a tritrophic approach
Poligui, René Noël ULg; Francis, Frédéric ULg; Haubruge, Eric ULg

Poster (2011, May 24)

The aphid Aphis gossypii Glover (Homoptera: Aphididae) is known as worldwide important pest. It causes serious injuries to crops, but is also able to feed on various cultivated and wild plants. Some ... [more ▼]

The aphid Aphis gossypii Glover (Homoptera: Aphididae) is known as worldwide important pest. It causes serious injuries to crops, but is also able to feed on various cultivated and wild plants. Some programs are developped to control this aphid. In many studies , hoverfy Episyrphus balteatus De Geer (Diptera : Syrphidae) is used as an efficient and aphid specific predator in biological control systems. In this work, we study cotton aphid choice plant discrimination, the effect of host plants on its developpment(fecondity and mortality), and the E.balteatus foraging and oviposition behavior according aphid host plants. Biologic parameters were observed using various plant combinations. E.balteatus behavioral observations were conducted using the Noldus Observer v.5.0. A.gossypii makes discriminant choice of his hosts, with better preference on Cucurbita pepo L. (Cucurbitaceae) and Capsicum annuum L. (Solanaceae). Dacryodes edulis (G. Don) H.J. Lam. (Burseraceae) and Vicia faba L. (Fabaceae) are the midle choice while Hibiscus sabdariffa L. (Malvaceae) is less chosen. A.gossypii develops easily on C.pepo, and weakly on C.anuum, H.sabdariffa,and V.faba. D. edulis induces very high mortality to A.gossypii. According to E. balteatus behavior, A. gossypii is more attractive when infesting C .pepo and V.faba, less on H. sabdariffa. While non infested , the hoverfly more attractive plant is V.faba. Our results highlited the importance of interactions between aphids and their host plants and the prey-host influence on a specific aphid predatory hoverfy. Suitable ways in correlation with this work are to investigated to complete this study and perform aphids biological control. [less ▲]

Detailed reference viewed: 56 (2 ULg)
Full Text
See detailScreening Elisa method to assess in vitro efficacy of new agents based on Lactoperoxydase system against phytopathogens
Bafort, Françoise ULg; Lepoivre, Philippe ULg; Jijakli, Haissam ULg et al

Poster (2011, May 24)

The lactoperoxydasesystem (LPS) is a natural biological protection system in human saliva, milk and tears. Lactoperoxydase catalyzes the oxidation of iodide (I-) and thiocyanate (SCN-) in presence of ... [more ▼]

The lactoperoxydasesystem (LPS) is a natural biological protection system in human saliva, milk and tears. Lactoperoxydase catalyzes the oxidation of iodide (I-) and thiocyanate (SCN-) in presence of hydrogen peroxide in hypoiodite (OI-) and hypothiocyanite (OSCN-) ions. Both ions have inhibitory action against pathogenic bacteria, fungi and viruses. Until now, the ions OI- and OSCN- applied separately from the LPS were not tested against plant pathogens. Seventeen KI/KSCN/H2O2 ratios with 3 dilutions for each one were tested against Botrytiscinerea. Results showed that the ions OI- and OSCN- gives a better % of inhibition with: -high concentration of KI+KSCN, -a ratio of KI/KSCN of 4.5 and -a ratioof (KI+KSCN)/H2O2 near 1. Increased dilution combined with lower KI+KSCN concentration reduced the efficacy of the ions. From the screening against B.cinerea, 4 ratios of KI+KSCN were selected and tested against 6 other phytopathogens. Results showed that the OI- and OSCN- ions give 87 and 100% inhibition against Penicillium expansum and Verticillium dahlia respectively. The inhibitory activity of the ions solution was ranged between 70 and 79% regarding Fusarium avenaceum, Phytophthora infestans and Colletotrichum lindemuthanium. The ions OI- and OSCN- showed an insufficient inhibitory activity against Septoria tritici. The screening method highlighted that high KI/KSCN ratios and low dilution were more efficient against phytopathogens. The efficient ratios will be further evaluated in vivo. [less ▲]

Detailed reference viewed: 101 (27 ULg)
Full Text
See detailVolatile organic compounds of the roots of barley and their role in the rhizosphere
Fiers, Marie ULg; Barsics, Fanny ULg; Camerman, Marc ULg et al

Poster (2011, May 24)

Volatile organic compounds emitted by plants are known to intervene with various biotic environmental factors. Up to now, most of the studies have been focused on aerial volatiles and root liquid exudates ... [more ▼]

Volatile organic compounds emitted by plants are known to intervene with various biotic environmental factors. Up to now, most of the studies have been focused on aerial volatiles and root liquid exudates. Very few researches have been completed concerning belowground volatiles released into the rhizosphere despite their potential capacity to carry information between organisms. The Rhizovol project, started in autumn 2010, involves 5 different units of Gembloux Agro-Bio Tech collectively studying the production of belowground volatiles by barley roots underlying various biotic interactions in the rhizosphere. Some preliminary results of each partner of the project will be presented. To achieve this goal, analytical methods allowing the sampling, separation, identification and quantification of belowground volatile compounds have to be developed, taking into account their potential modifications in the rhizosphere once released by the roots. They enable the subsequent characterization and study of the interactions between barley and its rhizospheric partners chosen for this study. These interactions imply three types of organisms: beneficial organisms, pathogenic agents and plant and insect pests. Beneficial organisms can promote the growth of barley by the emission of volatiles; on the other hand barley can support their growth and metabolism. These phenomenons will be assessed by the study of 19 strains of plant growth-promoting bacteria (PGPR). Three pathogenic agents - two fungi (Fusarium culmorum and Cochliobolus sativus) and one virus (Barley yellow dwarf virus) - were chosen as they are known to cause various diseases on barley, especially on roots. The attractive or repellent effects of barley root volatiles on the pathogenic agents or their vectors, as well as the effect of volatiles on the diseases evolution will be evaluated. The project also includes several types of pests such as plants and insects. Plants can compete with barley for space and nutrients through volatile interactions. This will be assessed by the study of autotoxicity by barley itself and allelopathy with 8 weeds and a hemiparasitic plant (Rhinanthus minor). The effects of barley volatiles can also impact the severity of the attacks by insects. This part will be conducted with wireworms as they represent worldwide known pests, and aphids, through their viral vector role. Eventually, as soil characteristics can strongly influence the diffusion of volatile compounds, the diffusion behaviour of the identified volatile biomolecules through the soil will be modelled. Tritrophic interactions (e.g. insect-plant-pathogenic fungi) will be studied based on each bitrophic interaction results. Over-all, the Rhizovol project aims at improving the knowledge of interactions mediated by volatile compounds in the rhizosphere and at establishing new biocontrol methods that could contribute to integrated disease and pest management systems. [less ▲]

Detailed reference viewed: 84 (19 ULg)
Full Text
Peer Reviewed
See detailEVALUATION FOR RESISTANCE TO APHIDS OF WHEAT GERMPLASM RESOURCES IN CHINA
Zhou, Haibo ULg

Poster (2011, May 24)

Host plant resistance plays important roles in controlling pests and protecting of natural enemies in an agroecosystem, and the effect of insect resistant varieties in reducing damage is conspicuous ... [more ▼]

Host plant resistance plays important roles in controlling pests and protecting of natural enemies in an agroecosystem, and the effect of insect resistant varieties in reducing damage is conspicuous. Fuzzy recognition technique evaluation were used to determine sources of resistance in wheat to populations of the wheat aphids in five field experiments over 2 years in wheat-producing areas of China. Results showed that the majority of wheat varieties identified were susceptible to aphids, and no immune and highly resistant varieties was observed. The mean percentage from the wheat varieties with resistant, lowly susceptible, moderately susceptible and highly susceptible to aphid were 9.30%, 23.15%, 42.32%, and 25.23% in whole wheat varieties respectively. 5 wheat varieties (Lantian18, Lantian20, Lantian22, Lantian00-30 and Shanmai175) were moderately resistant in Jiangyou in 2009, other resistant sources were low levels for aphid-resisant. And more importantly, 2 wheat varieties (Lantian20, Lantian22) with the continuous resistance to wheat aphid in the five experimental fields over 2 years were found. Although resistance of wheat varieties had a close relation to their genetics and inheritance, we also found that the evaluation result of the same wheat varieties were varied in different place. The results indicated that the resistance to aphid could be affected by geographical environment.These evaluations on reaction to aphid metapopulation that could be crucial when germplasm is used in crosses to improve wheat cultivars. This research is part of program to evaluate germplasm for useful traits and make this information available to the germplasm system. [less ▲]

Detailed reference viewed: 42 (4 ULg)
See detailStand structure of mosquitoes (Diptera: Culicidae) in farms and establishment of a new potential vector of West Nile Virus for Belgium
Boukraa, Slimane ULg; Zimmer, Jean-Yves ULg; Simonon, Grégory ULg et al

Poster (2011, May 24)

Many Diptera, spread across the globe are likely to play a role in the transmission of various human and animal diseases. Mosquitoes in particular, give rise to various countries on research increasingly ... [more ▼]

Many Diptera, spread across the globe are likely to play a role in the transmission of various human and animal diseases. Mosquitoes in particular, give rise to various countries on research increasingly expanded and deepened. To better understand the structure of the Culicidae at cattle farms in Belgium and identify habitats favorable to the development of each species, a taxonomic inventory was conducted in 2008 and 2009 in ten different sites. They fall into five natural regions: Condroz, Ardenne, Fagne-Famenne, Lorraine and Compine. The collection of mosquitoes is based on sampling of larvae in 13 biotopes such as water troughs, tires, abandoned utensils and temporary puddles or not. The results of the morphotaxonomic study of the mosquitoes collected in the different study sites show the presence of five species of Culicidae divided into three genera, Anopheles, Culex and Culiseta. Of the 1843 individuals examined in 2009, Culex pipiens represents 79.98% of the total harvest. A new species is reported for Belgium, Culex modestus Ficalbi, 1890. This species is one of the most important from an epidemiological and medical-veterinary entomology, given its role in the transmission of West Nile and myxomatosis viruses. [less ▲]

Detailed reference viewed: 92 (30 ULg)
See detailA semiochemical enhancing the attractiveness of aphidophagous predators in potato crops
Leroy, Pascal ULg; Vandereycken, Axel ULg; Sabri, Ahmed ULg et al

Poster (2011, May 24)

Aphids are major pests of crops worldwide and the use of pesticides has led to resistant populations. The integration of aphid natural enemies in integrated management programs could be an option, but ... [more ▼]

Aphids are major pests of crops worldwide and the use of pesticides has led to resistant populations. The integration of aphid natural enemies in integrated management programs could be an option, but their efficacy is often limited by their quick dispersal from the ecosystem where they are released. Here, using wind-tunnel and field experiments, we have demonstrated that 3-Methyl-2-butenal acts as an efficient attractant and ovipositional stimulant for the hoverfly Episyrphus balteatus (De Geer) (Diptera: Syrphidae), enhancing its efficiency as biological control agent in crop fields. Wind-tunnel assays allowed determining that a minimal dose of 250 µg of 3-Methyl-2-butenal is required to attract the hoverflies over a distance of 2.5 m while a minimal dose of 500 µg is needed to induce the oviposition. Both attraction and oviposition increased proportionally to the tested doses showing that hoverflies are able to regulate their oviposition according to the chemical stimuli from their environment. In field experiments, both Syrphidae and Chrysopidae were strongly attracted by the 3-Methyl-2-butenal at a dose of 10 mg which also induces the oviposition of these two aphid predators in potato crops. This study also highlighted that hoverflies are the most abundant aphid predators found in natural environment. Against aphids, the use of this semiochemical could certainly enhance the efficiency of natural enemies. Furthermore, the use of the chemical cue 3-Methyl-2-butenal could provide a novel approach to control aphids in field and greenhouse systems. [less ▲]

Detailed reference viewed: 104 (26 ULg)
Full Text
See detailActivity-Flexibility and Stability Relationships as revealed by multiple mutants of a psychrophilic alpha-Amylase
Cipolla, Alexandre ULg; D'Amico, Salvino ULg; Feller, Georges ULg

Poster (2011, May 23)

Permanently cold environments, like polar regions, have been colonized by a great variety of psychrophilic organisms producing enzymes adapted to function efficiently at low temperatures. We have ... [more ▼]

Permanently cold environments, like polar regions, have been colonized by a great variety of psychrophilic organisms producing enzymes adapted to function efficiently at low temperatures. We have investigated the role of weak interactions in thermal adaptation of proteins by site-directed mutagenesis of the psychrophilc alpha-amylase (AHA) from the Antarctic bacterium Pseudoalteromonas haloplanktis. Two stabilized multiple-mutants (Mut5 and Mut5CC) have been constructed. The single mutations were selected by comparison of the presence of weak interactions in a mesophilic homolog from pig pancreas, PPA. The three enzymes AHA, Mut5 and Mut5CC have been analyzed by differential scanning calorimetry, thermal and chemical denaturation. The flexibility has been studied by acrylamide-induced fluorescence quenching. In order to investigate the kinetic origin of the gain in stability, the kinetics of unfolding and refolding in GdmCl have been monitored at 15°C. The newly introduced weak interactions stabilized the mutants, protected them against heat and chemical unfolding and also induced an effective loss of flexibility. In addition, the two multiple-mutants exhibit an increased optimum temperature for activity. The first results of kinetic studies show a similar refolding phase but differences between the three amylases in the unfolding phase. These results unambiguously support the capital role of weak interactions in the balance between activity, flexibility and stability and provide a better knowledge of the adaptation of enzymes to cold temperatures. [less ▲]

Detailed reference viewed: 41 (9 ULg)
Peer Reviewed
See detailBelgo-Serbian explorations on the massif of Durmitor (Montenegro) since 2008
Peeters, Alexandre ULg

Poster (2011, May 21)

Abstract: This poster relates the results of the Belgo-Serbian explorations on the massif of Durmitor (Montenegro) since 2008. These explorations were only possible thanks to the Serbian cavers of ASAK ... [more ▼]

Abstract: This poster relates the results of the Belgo-Serbian explorations on the massif of Durmitor (Montenegro) since 2008. These explorations were only possible thanks to the Serbian cavers of ASAK that we met in Lazareva, training camp in Serbia. Thereafter, the Serbian cavers gave us the opportunity of an exploration on the massif of Durmitor. For the Belgian cavers, this exploration was part of the federal training project Explo2009, whose purpose is to train the young cavers underground exploration. Regarding the results of these explorations, this poster details the discovery of the three main caves: Pedina sa ledom pod Bandijerne, l’ébouleuse and Fliš. Pedina sa ledom pod Bandijerne has long been known because of its entry porch which can be seen from the camp. With the discovery of a new passage in the chamber that follows the entrance, the exploration of this new réseau was done by the Serbian cavers in 2008 and was continued by the Belgian cavers in 2009, reaching the depth of 141 m.L’ébouleuse, which is near the Minin Bogaz pass, has been discovered in 2009. It has been completely explored in several days, reaching the bottom of the cave at the depth of 113 m. Last but not least, the main result of these explorations is Fliš. The exploration of this deep cave began in 2009 and is still in progress. The depth of 432 m was reached in 2009 and then 582 m in 2010. This cave is characterized by deep pits in which we can see the sequence of the sedimentary rocks, called Flysch. [less ▲]

Detailed reference viewed: 23 (5 ULg)
Full Text
Peer Reviewed
See detailZebrafish Skeleton Measurements using Image Analysis and Machine Learning Methods
Stern, Olivier ULg; Marée, Raphaël ULg; Aceto, Jessica ULg et al

Poster (2011, May 20)

The zebrafish is a model organism for biological studies on development and gene function. Our work aims at automating the detection of the cartilage skeleton and measuring several distances and angles to ... [more ▼]

The zebrafish is a model organism for biological studies on development and gene function. Our work aims at automating the detection of the cartilage skeleton and measuring several distances and angles to quantify its development following different experimental conditions. [less ▲]

Detailed reference viewed: 67 (19 ULg)
Full Text
Peer Reviewed
See detailEvaluation of the use of VEGF111 for the treatment of tendon lesions.
Janssen, Lauriane ULg; Kaux, Jean-François ULg; Drion, Pierre ULg et al

Poster (2011, May 20)

Alterations of tendons are common pathologies resulting from repetitive or abnormal mechanical sollicitations. Very frequently lesions become chronic and may even lead to rupture. As there is no current ... [more ▼]

Alterations of tendons are common pathologies resulting from repetitive or abnormal mechanical sollicitations. Very frequently lesions become chronic and may even lead to rupture. As there is no current efficient treatment for curing this type of diseases, new therapeutic approaches are being tested and developed. Injection of platelet-rich plasma (PRP) seems to be a promising treatment by local release of growth factors. Among these factors, VEGF-A is known to induce positive effects on vascular functions and angiogenesis, and could be implicated in the healing process of tendons. Several isoforms of VEGF-A have been described in literature, including VEGF165 and 121. VEGF111 is encoded by exons 1-4 and 8a. The lack of exon 5 enables VEGF111 to resist to proteolytic degradation and the absence of exons 6 and 7 reduces its affinity for several macromolecules present on the cell surface and in the extracellular matrix. In vivo, it has been shown to be highly proangiogenic and diffusible. A 5mm defect was surgically performed in the Achilles tendon of 60 rats. Two hours after closure of the fascia and the skin, an injection within the wound was performed with PBS alone (n=30) or with PBS containing 100 ng of VEGF111 (n=30). 10 rats of each group were sacrificed at days 5, 15 and 30. The operated tendon was then carefully removed and collected for either immunohistochemical analyses or mechanical testing. At each time point, the section and the overall appearance of the repairing tendons were similar for PBS and VEGF111-injected tendon. As compared to controls, injection of VEGF111 seemed to promote a faster angiogenesis, although the number of samples was at this stage too low for performing reliable statistical analysis. Mechanical resistance to rupture of the repairing tendons was also measured. No difference between the two groups was observed after 5 or 15 days. By contrast, increased tensile strength was clearly evidenced in the VEGF-treated group after 30 days. These preliminary data seem to indicate a positive effect of a single VEGF111 injection for restoring the mechanical properties of tendons after their section. Additional experiments are planned for confirmation purposes and for further characterizing the model. It includes a “dose- response” analysis, the use of VEGF165 as an additional control and a study evaluating the effect of several injections. [less ▲]

Detailed reference viewed: 85 (17 ULg)