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See detailGroundwater flow and transport modelling at regional scale: lessons learned from different applications in the Walloon Meuse basin
Dassargues, Alain ULg; Goderniaux, Pascal; Orban, Philippe ULg et al

Conference (2016, July 28)

An overview is proposed of the recent groundwater modelling works, at the groundwater body scale, performed by the Hydrogeology & Environmental Geology team of the University of Liège. The developed ... [more ▼]

An overview is proposed of the recent groundwater modelling works, at the groundwater body scale, performed by the Hydrogeology & Environmental Geology team of the University of Liège. The developed modelling tools are built in the general objective of improving our understanding and management, at short, middle and long terms, of the groundwater bodies. The general strategy to be followed implies that conceptualization, parameterization and calibration must be adapted to the actual objectives of each model (Wildemeersch et al., 2014). 3 specific applications are illustrated involving two main groundwater bodies: - application of the HFEMC method (Wildemeersch et al., 2010) within the SUFT3D code for groundwater flow modelling of the ‘Synclinorium of Dinant’ (Orban et al., 2010 and Brouyère et al., 2011); - application of the HFEMC method and the SUFT3D code for the nitrate trends (Batlle-Aguilar et al., 2007) simulations in the Geer basin (Orban et al., 2010) for different scenarios of nitrate inputs; - application of the HGS integrated model for assessing the impact of climate change on the groundwater reserves in the Geer basin (Brouyère et al., 2004, Goderniaux et al., 2009 and 2011) with quantification and comparison of the different uncertainty sources (Goderniaux et al., 2015) Lessons and perspectives are learned and proposed from these modelling experiences at the scale of the groundwater body. [less ▲]

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See detailHow groundwater interactions can influence UPSH (Underground Pumping Storage Hydroelectricity) operations
Bodeux, Sarah ULg; Pujades, Estanislao ULg; Orban, Philippe ULg et al

Conference (2016, July 28)

In the current energy grid, renewable energy has an increasing role to play. However, their intermittence cannot afford to regulate the produced electricity according to the irregular demand (Evans et al ... [more ▼]

In the current energy grid, renewable energy has an increasing role to play. However, their intermittence cannot afford to regulate the produced electricity according to the irregular demand (Evans et al., 2012). Pumped Storage Hydroelectricity (PSH) is a well-known efficient technology to store and release electricity according to the demand needs but appropriate potential new sites are getting scarce (Steffen, 2012). An innovative alternative consists in using abandoned mines as lower reservoir of an Underground Pumping Storage Hydroelectricity (UPSH) plant. In such configuration, large amount of water will be pumped or injected in underground cavities, creating subsequently head oscillations in the surrounding aquifers. Consequently, this seepage occurring between the considered cavity and the varying groundwater heads in the surrounding geological medium may influence the efficiency of the UPSH plant but also the magnitude of the potential impacts on the groundwater resources. A hybrid 3D finite element mixing cell method (Brouyère et al., 2009) is used to simulate numerically the use of a representative UPSH cavity and calculate the induced changes in groundwater heads in the surrounding geological medium. Different scenarios are computed varying parameter values (hydrogeological and lower reservoir characteristics), boundary conditions, and pumping/injection time-sequences. By analyzing the computed piezometric heads at different distances from the underground reservoir, the magnitude of the aquifer response to pumping storage operations is assessed. The most expected and noticeable effect is the oscillation of groundwater levels. The existence a mean pseudo/ dynamic steady-state and the required time to reach it are also determined. The head difference and its time evolution between the cavity and the surrounding medium is triggering the leakage of groundwater into the cavity or the contrary. The resulting effects on the UPSH plant efficiency can be estimated. Combining these outcomes, some feasibility criteria of this type of projects are identified. Going into practice, further models should include more in de-tails local and specific geometrical and hydrogeolog-ical data of the considered old mine cavities used as lower reservoir. This kind of modelling approach can be used as a first approach for determining how the aquifer will response to short and long term changes in UPSH pumping/injection schemes. [less ▲]

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See detailDe la crise à l’entreprise, en passant par vous…
Choffray, Jean-Marie ULg

Book published by Amazon, Kindle Edition (2016)

« Si un homme a de la chance, avant de mourir, il rassemblera autant qu'il le peut son patrimoine culturel pour le transmettre à ses enfants. Et jusqu’à son dernier souffle, il sera reconnaissant d’avoir ... [more ▼]

« Si un homme a de la chance, avant de mourir, il rassemblera autant qu'il le peut son patrimoine culturel pour le transmettre à ses enfants. Et jusqu’à son dernier souffle, il sera reconnaissant d’avoir pu laisser cet héritage inépuisable, sachant que c'est notre mère nourricière et notre vie éternelle. » (W. and A. Durant, 1968) « De la crise à l’entreprise, en passant par vous » est une invitation à l’action, à la prise de responsabilité, à la création responsable de valeur économique et à la recherche obstinée d’une croissance rentable. Oui ! Notre monde vient d’échapper à un effondrement systémique dont 1929 n’aurait constitué qu’un aimable préambule. Oui ! L’entreprise privée est le seul acteur social créateur de richesse économique et la solution la plus adaptée au mal qui se répand. Oui ! Il est extrêmement difficile de changer quoi que ce soit sur terre et d’apprendre à dire « non ! » En cas d’échec, le coût est connu : licenciement, exil, condamnation à mort ! L’objet de cet ouvrage est de partager le fruit d’une réflexion menée au cours de ces dernières années sur le rôle de l’entreprise dans l’environnement exceptionnel que nous connaissons depuis la Grande Récession de 2008-2009. Il aborde les causes et les conséquences de cet événement financier, industriel et politique historique ; le rôle de l’entreprise privée, de l’innovation et des entrepreneurs – eh oui ! vous… –, dans la recherche d’une solution ; et, enfin, les principales leçons de l’histoire à la lumière de ce qu’advint de l’œuvre de quelques grands hommes, innovateurs et agents du changement : Steve Jobs, Napoléon Bonaparte, et Jésus de Nazareth. Ecrire sur des thèmes aussi complexes, et aussi lourds de conséquences pour notre devenir commun, est un véritable défi et invite à la modestie. J’espère que les choix effectués mériteront votre investissement, votre attention et votre temps ! [less ▲]

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

Poster (2016, July 27)

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

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

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

Poster (2016, July 26)

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

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

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See detailApports phénoménologiques à l’étude de la relation au corps dans le jeu vidéo
Delbouille, Julie ULg

in Implications philosophiques (2016)

J’évite un obstacle. Je cours. Je saute. Alors que quelques notes de musique m’avertissent de l’échec de ce dernier mouvement, je vois mon corps chuter, happé par le vide au-delà de l’écran. Cette scène ... [more ▼]

J’évite un obstacle. Je cours. Je saute. Alors que quelques notes de musique m’avertissent de l’échec de ce dernier mouvement, je vois mon corps chuter, happé par le vide au-delà de l’écran. Cette scène, qui tout comme ses multiples variations s’inscrit en filigrane au cœur de nombreuses expériences vidéoludiques, soulève la question du rapport au corps dans le jeu vidéo. Dans le champ des Game et des Play Studies, nombreux sont les chercheurs qui se sont déjà emparés de l’interactivité comme objet d’étude, et d’une de ses modalités dans le jeu vidéo : l’avatar. Interface récurrente entre le joueur et l’univers vidéoludique, nous postulons que cette « enveloppe pilotable » constitue une porte d’entrée pour envisager la problématique corporelle dans le jeu vidéo. En effet, la fonction d’incarnation permise par l’avatar ajoute à la relation entre le corps et l’esprit du joueur une dimension nouvelle : celle du corps virtuel. Ce corps « autre », dont le joueur prend possession, constitue une des conditions de son « insertion » dans le monde du jeu. [less ▲]

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See detailInvestir ou mourir, il faut choisir…
Choffray, Jean-Marie ULg

Book published by Amazon, Kindle Edition (2016)

Investir : c’est croire en l’avenir. C’est renoncer en partie au présent pour donner vie au futur. C’est tourner le dos aux « bouffeurs d’espoir » et à l’illusoire confort du statu quo. Enfin, et surtout ... [more ▼]

Investir : c’est croire en l’avenir. C’est renoncer en partie au présent pour donner vie au futur. C’est tourner le dos aux « bouffeurs d’espoir » et à l’illusoire confort du statu quo. Enfin, et surtout, c’est oser « oser » ! La distance séparant le discours public de la performance économique avérée suffit à démontrer l’incompréhension des mécanismes de création de richesse de ceux qui sont censés en avoir la maîtrise et/ou les mettre en œuvre. Il est peu de domaines où les illusions, et autres idées fausses, ont un succès tel qu’elles amènent à s’interroger sur le profit que d’aucuns pourraient en tirer… L’objet de cet ouvrage est de partager le fruit d’une réflexion menée sur le thème de l’investissement, forme proéminente et condition première de l’activité économique, au moment où certains s’interrogent sur son encadrement et cherchent à en limiter la liberté. Il aborde les bouleversements technologiques les plus significatifs ; l’art et la science d’investir avec Internet ; la recherche d’opportunités nouvelles ; et, se termine par quelques observations et souhaits quant à « l’état » du monde ! [less ▲]

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See detailHCOOH distributions from IASI for 2008-2014: comparison with ground-based FTIR measurements and a global chemistry-transport model
Pommier, M.; Clerbaux, C.; Coheur, P.-F. et al

in Atmospheric Chemistry and Physics (2016), 16

Formic acid (HCOOH) is one of the most abundant volatile organic compounds in the atmosphere. It is a major contributor to rain acidity in remote areas. There are, however, large uncertainties on the ... [more ▼]

Formic acid (HCOOH) is one of the most abundant volatile organic compounds in the atmosphere. It is a major contributor to rain acidity in remote areas. There are, however, large uncertainties on the sources and sinks of HCOOH and therefore HCOOH is misrepresented by global chemistry-transport models. This work presents global distributions from 2008 to 2014 as derived from the measurements of the Infrared Atmospheric Sounding Interferometer (IASI), based on conversion factors between brightness temperature differences and representative retrieved total columns over seven regions: Northern Africa, southern Africa, Amazonia, Atlantic, Australia, Pacific, and Russia. The dependence of the measured HCOOH signal on the thermal contrast is taken into account in the conversion method. This conversion presents errors lower than 20 % for total columns ranging between 0.5 and 1 × 1016 molec/cm2 but reaches higher values, up to 78 %, for columns that are lower than 0.3 × 1016 molec/cm2. Signatures from biomass burning events are highlighted, such as in the Southern Hemisphere and in Russia, as well as biogenic emission sources, e.g., over the eastern USA. A comparison between 2008 and 2014 with ground-based Fourier transform infrared spectroscopy (FTIR) measurements obtained at four locations (Maido and Saint-Denis at La Réunion, Jungfraujoch, and Wollongong) is shown. Although IASI columns are found to correlate well with FTIR data, a large bias (> 100 %) is found over the two sites at La Réunion. A better agreement is found at Wollongong with a negligible bias. The comparison also highlights the difficulty of retrieving total columns from IASI measurements over mountainous regions such as Jungfraujoch. A comparison of the retrieved columns with the global chemistry-transport model IMAGESv2 is also presented, showing good representation of the seasonal and interannual cycles over America, Australia, Asia, and Siberia. A global model underestimation of the distribution and a misrepresentation of the seasonal cycle over India are also found. A small positive trend in the IASI columns is observed over Australia, Amazonia, and India over the 2008–2014 period (from 0.7 to 1.5 %/year), while a decrease of ∼ 0.8 %/year is measured over Siberia. [less ▲]

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See detailEpiphytic bryozoans on Neptune grass – a sample-based data set
Lepoint, Gilles ULg; Heughebaert, André; Michel, Loïc ULg

in ZooKeys (2016), 606

Background The seagrass Posidonia oceanica L. Delile, commonly known as Neptune grass, is an endemic species of the Mediterranean Sea. It hosts a distinctive and diverse epiphytic community, dominated by ... [more ▼]

Background The seagrass Posidonia oceanica L. Delile, commonly known as Neptune grass, is an endemic species of the Mediterranean Sea. It hosts a distinctive and diverse epiphytic community, dominated by various macroalgal and animal organisms. Mediterranean bryozoans have been extensively studied but quantitative data assessing temporal and spatial variability have rarely been documented. In Lepoint et al. (2014a, b) occurrence and abundance data of epiphytic bryozoan communities on leaves of P. oceanica inhabiting the Revellata Bay (Corsica, Mediterranean Sea) were reported and trophic ecology of Electra posidoniae Gautier assessed. New information Here, we provide metadata information on data set discussed in Lepoint et al. 2014a and published on the GBIF portal as a sampling-event data set: http://ipt.biodiversity.be/resource?r=ulg_bryozoa&v=1.0). The data set, compared to Lepoint et al. 2014a, is enriched by data concerning species settled on Posidonia scales (dead petiole of Posidonia leaves, remaining after limb abscission). [less ▲]

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See detailCounting time measurement and statistics in gamma spectrometry: the balance
Guembou Shouop, Cébastien Joel ULg; Ndontchueng Moyo, Maurice; Chene, Grégoire ULg et al

Poster (2016, July 11)

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

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

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See detailBallkani Perëndimor: terren veprimi i Bashkimit europian dhe fuqive emergjente?
Lika, Liridon ULg

Scientific conference (2016, July 11)

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See detailReproducibility of a tennis serve protocol
Tubez, François ULg; FORTHOMME, Bénédicte ULg; Croisier, Jean-Louis ULg et al

Conference (2016, July 08)

INTRODUCTION Serve in modern tennis game is a real offensive weapon for players. In kinematic analysis, it is the most studied stroke of this game because it is the only stroke played in a closed skill ... [more ▼]

INTRODUCTION Serve in modern tennis game is a real offensive weapon for players. In kinematic analysis, it is the most studied stroke of this game because it is the only stroke played in a closed skill. Players have a maximum of control on this stroke. It is unclear whether 3D kinematic tests are reproducible for the same player under identical conditions and if a familiarization session is necessary. In practice, with professional players, who have little time available to perform tests, familiarization sessions are difficult. The aim of our study is to measure the reproducibility of a 3D serve protocol test. METHODS Nine tennis players (righties, regional level, 20 ± 2 years) were asked to hit first flat serves in a 1 m² area placed on the "T" zone of deuce diagonal of the tennis court. Two identical tests are performed one week apart. For each test, we selected the three best serves of the 25 trials (with the highest speed and the highest accuracy). Kinetics measurements were performed using a 3D analysis system (Codamotion), a force platform (Kistler) and a radar gun. 28 markers were placed on the players’ bodies to measure kinematics of the movements: ankles, knees, hips, trunk, shoulder, elbow and wrist dominant side. We measured ball speed, leg drive, linear velocity of the racket and joints, joints range of motion and maximum angular velocities at different positions (armed, maximum external rotation and impact) (1). RESULTS All analyzed parameters (linear speeds of racket and joints, leg drive force, joint angles and angular velocities) are reproducible with exception of a small part of them. Our study shows that 5,7% (7 of 122 measurements) joint position parameters and 8,3% (4 of 48 measures) angular velocity parameters are not reproducible from a session to another. DISCUSSION Various errors sources encountered in 3D analysis can justify the presence of non-reproducible parameters (2-3). However, after this work, we can state that the established protocol provides reproducible results when analyzing the tennis serve. [less ▲]

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See detailClostridium difficile a new zoonotic agent? Assessment of human transmission potential of hypervirulent strains of Clostridium difficile through food products consumption
Rodriguez Diaz, Cristina ULg

Doctoral thesis (2016)

Clostridium difficile is a spore-forming anaerobic bacterium recognised as a major human pathogen responsible for pseudomembranous colitis and nosocomial-antibiotic associated diarrhea. Traditionally ... [more ▼]

Clostridium difficile is a spore-forming anaerobic bacterium recognised as a major human pathogen responsible for pseudomembranous colitis and nosocomial-antibiotic associated diarrhea. Traditionally, hospitals were considered the main reservoirs for infection. However, in the last years the incidence, deaths, complications and costs of C. difficile infection (CDI) have been rising, not only in healthcare facilities, but also within the community. In the community, it has been detected in a growing number of CDI cases in previously healthy individuals without antimicrobial exposure, hospital stay or any other classical risk factors. Furthermore, the disease has been repeatedly described in younger patients, including children. Some hypotheses have been proposed to explain this peak of community cases, the most obvious being that nowadays more attention is given to CDI surveillance. In the last years, diarrhea due to C. difficile disease might have gone undiagnosed, and in many cases went unreported, particularly in the community. Since 2004, severe outbreaks of CDI have been documented increasingly in the United States, Canada and in Europe. These outbreaks have been associated with the emergence of a novel strain, known as PCR-ribotype 027, characterised by higher than usual levels of toxins A and B production, and the presence of a third toxin named CDT or binary toxin. This strain type is also characterised by its resistance to both erythromycin and fluoroquinolones (i.e. moxifloxacin, gatifloxacin and levofloxacin). However, according to the latest hospital surveillance studies in Europe, since 2010 there is a decrease in the incidence rates of PCR-ribotype 027 while other PCR-ribotypes, including PCR-ribotypes 014, 020, 001, 002, 078 and 015 are increasing. Person to person contact is one source proposed for the spread in the community, occurring after visiting hospitalised patients or residents in long-term care facilities. Employees of these health-care settings can also carry spores and contaminate their entourage. The second hypothesis is contamination from the environment, following visits to a potentially contaminated place, such as hospitals or nursing homes. The two most important potential sources of CDI in the community, which have been demonstrated by investigations in the last decade are animals and foods. While C. difficile is also known as enteric pathogen in some food producing and companion animal species, there are several reports describing the presence of the bacterium in the intestinal contents of apparently healthy animals. Moreover, data published recently suggests animals as an important source of human CDI, which can spread disease through environmental contamination, direct or indirect contact, or food contamination, including carcass and meat contamination at slaughter or in the case of crops, through the use of organic animal manure. By definition, zoonoses are infectious diseases that can be transmitted directly or indirectly between animals and humans, through direct contact or close proximity with infected animals, or through the environment. Foodborne zoonotic pathogens are transmitted via the consumption of contaminated food or drink water. The first description of C. difficile in domestic animals and their environments dates from 1974 and possible foodborne transmission was reported for the first time in 1982. However, nowadays the importance of C. difficile as zoonotic disease remains largely unknown. The "One Health" concept is a worldwide strategy, which recognises that the health of humans and animals is connected and also depends on the environment. The present dissertation is a 5 year national study that has investigated the presence of C. difficile in animals and food, from “farm-totable”. The study was also extended to humans resident in a nursing home and in two hospitals in Belgium and in Spain. The characterisation of the isolates obtained has ultimately allowed comparison of the PCR-ribotype distribution in the different European hospitals, as well as with the PCR-ribotype distribution found in animals and foods. This work explores how C. difficile spreads among human patients, animals, foods and the environment to better understand the potential of the bacterium as a zoonotic or foodborne infectious agent. [less ▲]

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See detailNonlinear analysis of compliant mechanisms: application to tape springs
Dewalque, Florence ULg; Bruls, Olivier ULg

Poster (2016, July 07)

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

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

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

Poster (2016, July 07)

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

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

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

Poster (2016, July 07)

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

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See detailGamifier un quiz – Effet graduel sur la performance, l’immersion et la perception de compétence
le Maire, Nathalie ULg; Fauconnier, Marie-Laure ULg; Colaux, Catherine ULg et al

Conference (2016, July 06)

Dans un contexte marqué par l’arrivée d’une génération pour laquelle les technologies, les réseaux sociaux et les jeux en ligne relèvent de l’évidence (Stein, 2013; Weiler, 2004), le jeu a souvent été ... [more ▼]

Dans un contexte marqué par l’arrivée d’une génération pour laquelle les technologies, les réseaux sociaux et les jeux en ligne relèvent de l’évidence (Stein, 2013; Weiler, 2004), le jeu a souvent été qualifié de véhicule d’une pédagogie rendant l’étudiant acteur de son apprentissage, conférant une dimension de défi aux activités éducatives et générant une motivation intrinsèque (Foster, 2008; Kang & Tan, 2008; McFarlane et al., 2002; Mitchell & Savill-Smith, 2004; Papastergiou, 2009). Ce potentiel éducatif du jeu a cependant été souvent associé à des jeux immersifs (de Freitas, 2006) requérant la mise en œuvre d’une trame narrative et dont le développement peut s’avérer couteux. L’utilisation de mini-jeux est considérée comme une solution alternative à ces « serious games » complexes car ils permettent d’enseigner un grand nombre de concepts tout en générant de faibles coûts de développement (Illanas, Gallego, Satorre, & Llorens, 2008). Ceux-ci présentent des règles basiques, sont faciles à jouer et conçus comme objets d’apprentissage de sorte qu’il soit aisé pour l’étudiant de percevoir les informations essentielles et que leur pratique soit bénéfique pour l’apprentissage (Frazer, Argles, & Wills, 2007). La gamification, à savoir la transposition des principes issus de l’univers du jeu au domaine de l’éducation (Deterding, Dixon, Khaled, & Nacke, 2011), ne porte donc pas ici sur des jeux de simulation immersifs mais vise plus réalistement la transposition à des activités d’apprentissage d’un certain nombre de principes et de leviers à l’œuvre dans des mini-jeux populaires tel que Candy Crush. La question de recherche qui a guidé l’expérience décrite ci-après concerne l’évaluation du potentiel pédagogique de l’utilisation d’un mini-jeu de ce type dans un cours de chimie générale en complément des supports pédagogiques plus classiquement utilisés en première année d’université. Concrètement, ce mini-jeu appelé « Atomica » se présente comme un quiz d’entrainement portant sur un chapitre réputé difficile du cours, l’atomistique. Ce quiz a fait l’objet de quatre versions activant chacune un nombre croissant d’éléments de gamification (indiqués en gras) décrits par plusieurs auteurs comme étant les « ingrédients » ou « building blocks » d’un bon jeu (Bunchball Inc., 2010; Dignan, 2011; Reeves & Read, 2013) : - La version contrôle du QCM se présente comme similaire aux évaluations formatives couramment utilisées à l’université ; - La version 1 segmente le QCM en six niveaux de difficulté ; - La version 2 ajoute un feedback automatisé aux niveaux de difficulté ; - La version 3 présente une version maximaliste de la gamification puisque, aux éléments précédents, elle ajoute un compte à rebours, des indices dont l’appel engendre une perte de points, un classement des meilleurs joueurs et un indicateur social (possibilité de se situer par rapport à la communauté de joueurs). Ce choix d’un dispositif graduel se justifie notamment par l’intérêt pour la détection d’un seuil à partir duquel l’ajout d’éléments de gamification fait basculer la perception d’un quiz habituel vers un artefact relevant du mini-jeu et générant ainsi un état de flow chez le joueur. Chaque version a été soumise à un groupe d’une trentaine d’étudiants, selon une procédure expérimentale contrôlée, avec pour objectif la collecte de données (en cours) sur : - L’état de flow ou expérience optimale engendré par chacune des versions (orientation comparative) défini comme un état subjectif de bien-être (Csikszentmihalyi, 1990) engendrant une immersion totale dans l’activité. Afin de mesurer le flow, une échelle spécifique aux jeux éducatifs (EGameFlow) développée en 2009 (Fu, Su, & Yu, 2009) a été utilisée dans le cadre de cette étude. - Une des trois composantes du modèle de la dynamique motivationnelle de Viau, la perception du sentiment de compétence (Bandura, 1993; Pajares, 2014) considéré comme un moteur essentiel à l’apprentissage et un déterminant de l’intérêt pour une discipline scolaire. - La performance à un test de connaissance soumis aux étudiants avant et après l’expérience de jeu. Les motivations sous-tendant le processus d’exploration des mini-jeux sont à chercher du côté d’un certain discours pédagogique qui prône l’inscription d’une dimension ludique dans les apprentissages en enseignement supérieur. Nourrie par ses résultats expérimentaux, la communication proposera un retour réflexif plus général sur la valeur, les limitations et les conditions de réalisation de ce discours. [less ▲]

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

Poster (2016, July 06)

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

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

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