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See detailCARACTÉRISATION DE LA DIVERSITÉ GÉNÉTIQUE DE CULTIVARS D’OIGNON (ALLIUM CEPA L.) DU NIGER EN VUE DE LEUR CONSERVATION IN SITU ET DE LEUR AMÉLIORATION
Abdou, Rabiou ULg

Doctoral thesis (2014)

Plante monocotylédone, allogame, entomophile, avec un cycle cultural annuel pour la production des bulbes, bisannuel pour celle des graines, l’oignon est l’un des légumes le plus important au Niger en ... [more ▼]

Plante monocotylédone, allogame, entomophile, avec un cycle cultural annuel pour la production des bulbes, bisannuel pour celle des graines, l’oignon est l’un des légumes le plus important au Niger en raison de son utilisation en alimentation et en médecine. Le semis en pépinière suivi d’un repiquage des planches est le mode de culture le plus fréquent chez les producteurs nigériens. Cette étude explore la diversité génétique des cultivars d’oignon du Niger. La diversité est à comprendre ici au sens de la diversité nommée, la diversité morphologique et la diversité moléculaire. Cette thèse se propose d’utiliser ces trois approches complémentaires pour identifier et caractériser les variétés et écotypes selon la perception des producteurs, de caractériser la diversité morphologique et agronomique à partir des descripteurs du genre Allium établis par Bioversity International, et d’analyser la diversité moléculaire des variétés et écotypes d’oignon du Niger à partir des marqueurs moléculaires microsatellites. Cinquante-deux écotypes nommés ont été inventoriés, mais après analyse et regroupement des synonymes, il ressort que dix-sept écotypes sont cultivés au Niger. Les principaux critères des paysans pour caractériser un écotype local sont la couleur des bulbes et la zone de provenance. Les variables quantitatives et qualitatives les plus distinctives entre les écotypes d’oignon sont la longueur et le diamètre des feuilles, le poids des bulbes, la couleur des feuilles, la forme et la couleur des bulbes, l’uniformité de la forme et de la couleur des bulbes. La distance génétique est plus grande, d’une part, entre les écotypes les plus éloignées géographiquement, et d’autre part, entre les écotypes les plus différents au niveau des caractères morphologiques. Le nombre de morphotypes varie de un à neuf par écotype testé. Les analyses moléculaires confirment la forte variabilité à l’intérieur des écotypes et les conclusions relatives à la distance génétique observée à partir des données morphologiques. A l’issue de ces travaux de caractérisation génétique de l’oignon, il est donc utile de combiner des stratégies de conservation in situ et ex situ, et l’exploitation de ces ressources génétiques pour améliorer la production et la rusticité des cultivars d’oignon du Niger. [less ▲]

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See detailRegards sur la "Wallonie prussienne" et la Première Guerre mondiale
Brüll, Christoph ULg

Conference given outside the academic context (2014)

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See detailCannabis use initiation among adolescents: the predictive role of peers, alcohol, expectancies and internalizing factors.
Schmits, Emilie ULg; Mathys, Cécile ULg; Quertemont, Etienne ULg

Conference (2014, September 05)

Theoretical background: Cannabis is the most commonly used illicit drug among teenagers. Initiation is influenced by environmental factors and personal characteristics, events or experiences. An early ... [more ▼]

Theoretical background: Cannabis is the most commonly used illicit drug among teenagers. Initiation is influenced by environmental factors and personal characteristics, events or experiences. An early initiation increases the risks of problems related to cannabis use (e.g. negative psychosocial effects, delinquent behaviors, mental disorders). Prevent initiation, through the identification of risk/protective factors and their interaction, seems crucial in terms of public health. Research question and significance: This study aimed to examine the progression of use, to identify protective and risk factors of cannabis initiation (including peers, alcohol, expectancies and internalizing factors) and to specifically focus on the influence of social anxiety and its moderators/mediators. Methods: A questionnaire was administered twice to 877 teenagers (49.94% female, M=15.61) with one year interval. Sex, age, demographic variables, peer cannabis use, cannabis-related variables (lifetime, frequency, problems and expectancies), alcohol use, social anxiety, trait-anxiety and depression were assessed through validated scales. Logistic regressions, mediation and moderation analyzes were performed. Results: During the follow-up period, 12.89% of the young participants initiated cannabis use. Several factors significantly predict initiation: alcohol use, peer users, perceptual enhancement and craving effect expectancies. Others factors significantly protect from initiation: negative behavioral effect expectancies and social anxiety. Gender, age, relaxation/social facilitation and cognitive impairment effect expectancies, trait-anxiety and depression do not significantly influence cannabis use initiation. In moderated mediation model, after controlling for relevant variables, social anxiety protected from initiation trough the mediating role of perceptual enhancement and craving effect expectancies. The number of peer users and alcohol use do not moderate this mediation. Negative behavioral effect expectancies do not significantly mediate the relation between social anxiety and cannabis initiation. Interpretation of findings: Through low positive expectancies, adolescents with social anxiety symptoms are less likely to initiate cannabis use than the others, whatever the number of peer users and the alcohol use. Findings are discussed in terms of risk and protective characteristics of relevant factors, in an overall and evolutionary approach including internalizing factors. Results support the identification of internalizing profile of adolescents concerned by prevention or treatment and the importance of social anxiety and expectancies in intervention. [less ▲]

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See detailIs Geometallurgy Teachable? A challenge for the new Erasmus Mundus EMerald
Pirard, Eric ULg

Conference (2014, September 05)

designate any kind of advanced ore characterisation prior to mineral processing operations while in fact it should clearly refer to a multidisciplinary integration of geological, mining, metallurgical ... [more ▼]

designate any kind of advanced ore characterisation prior to mineral processing operations while in fact it should clearly refer to a multidisciplinary integration of geological, mining, metallurgical, environmental and economic information into a single orebody model. In order to instil the best available geometallurgical practices in the professional world, it seems essential to break the traditional cleavages among disciplines and educate a new generation of engineers. The Erasmus Mundus EMerald “Master in Georesources Engineering” program initiated by four European universities under the coordination of University of Liege, has been designed to exactly tackle this challenge. It is not surprising that this program has been set up by universities having a long tradition in mixing a double perspective of geology and engineering (Nancy; Lulea; Liege and Freiberg). Geometallurgy requires both an excellent understanding of the natural variability and complexity of an ore and a comprehensive overview of the techniques available to extract and concentrate any valuable material. The course program has been designed to achieve a right balance between knowledge of mineral resources (geology, resource characterisation, reserve estimation, modelling) and processing (comminution, preconcentration, leaching, waste disposal,...). It also includes a broader view on life cycle analysis and urban mining. A series of professional seminars, suggested by an industrial advisory board, shed light on strategic issues, economic and environmental challenges, corporate social responsibilities, etc. Mobility and multicultural experience is an added-value of the Erasmus Mundus experience which definitely contributes to breeding engineers for tomorrow. [less ▲]

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See detailObservational signatures of past mass-exchange episodes in massive binaries
Raucq, Françoise ULg; Rauw, Grégor ULg; Gosset, Eric ULg et al

Poster (2014, September 05)

Mass and momentum exchanges in massive binaries can produce several observational signatures, such as asynchronous rotation and altered chemical compositions, which remain once the stars detach again. We ... [more ▼]

Mass and momentum exchanges in massive binaries can produce several observational signatures, such as asynchronous rotation and altered chemical compositions, which remain once the stars detach again. We have started to investigate these effects for a sample of detached massive O-star binaries that are thought to have previously experienced a Case A Roche lobe overflow. Using phase-resolved spectroscopy, we perform the disentangling of the spectra of the two stars. The reconstructed primary and secondary spectra are then analyzed to determine a range of stellar effective temperatures and gravity, as well as rotational velocities. Using model atmosphere codes we also constrain the chemical composition of the components. In this contribution, we present the first results of our analyses of HD149404 (O7.5If + ON9.5I, P = 9.81 days). [less ▲]

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See detailMulti-period Stochastic Optimization Problems in Transportation Management
Pironet, Thierry ULg

Doctoral thesis (2014)

The topic of this thesis in management science is to propose a methodology to tackle multi-period decision problems including stochastic forecasts and to apply it to the field of transportation management ... [more ▼]

The topic of this thesis in management science is to propose a methodology to tackle multi-period decision problems including stochastic forecasts and to apply it to the field of transportation management. This methodology relies mostly on a sequence of numerical experimentations based on a set of algorithms to assess the value of the multi-period setting and the interest to use the stochastic information contained in the forecasts. Moreover, a statistical validation method to compare the performances of algorithms enables us to rank them meaningfully. From theory to practice, the thesis is structured into four parts. Firstly, we define the thesis subject and content. Then, based on a literature review, we present the past and present issues within the research field: "Optimization in Transportation". Mainly, we define the differences between multi-period stochastic models and classical deterministic mono-period ones. We explain how dynamism and stochasticity are taken into account within transportation problems. Secondly, our methodology, which is our main contribution, is exposed from a generic point of view in the theoretical research field: "Multi-period Stochastic Optimization Problems". On the one hand, temporal parameters and computational issues in multi-period optimization are detailed; on the other hand a summary of optimization techniques and algorithms for stochastic optimization problems is provided. Afterwards, the statistical validation of algorithmic performance is discussed. Then, part three contains two applications that lead us to set up the methodology, following an inductive method. The first problem, based on an industrial application at the start of the research, investigates a "multi-period vehicle loading problem with stochastic release dates". The second application, based on a more generic approach for the deployment of the methodology, deals with a "multi-period vehicle assignment problem with stochastic load availability". Finally, in the fourth part, we conclude on the thesis contributions and propose some perspectives. [less ▲]

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See detailGuidance on current good radiopharmacy practice for the small-scale preparation of radiopharmaceuticals using automated modules: a European perspective
Aerts, Joël ULg; Ballinger, james; Behe, Martin et al

in Journal of Labelled Compounds & Radiopharmaceuticals (2014), 57

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See detailThe PLATO 2.0 Mission
Rauer, H.; Catala, C.; Aerts, C. et al

in Experimental Astronomy (2014)

PLATO 2.0 has recently been selected for ESA’s M3 launch opportunity (2022/24). Providing accurate key planet parameters (radius, mass, density and age) in statistical numbers, it addresses fundamental ... [more ▼]

PLATO 2.0 has recently been selected for ESA’s M3 launch opportunity (2022/24). Providing accurate key planet parameters (radius, mass, density and age) in statistical numbers, it addresses fundamental questions such as: How do planetary systems form and evolve? Are there other systems with planets like ours, including potentially habitable planets? The PLATO 2.0 instrument consists of 34 small aperture telescopes (32 with 25 s readout cadence and 2 with 2.5 s candence) providing a wide field-of-view (2232 deg 2) and a large photometric magnitude range (4–16 mag). It focusses on bright (4–11 mag) stars in wide fields to detect and characterize planets down to Earth-size by photometric transits, whose masses can then be determined by ground-based radial-velocity follow-up measurements. Asteroseismology will be performed for these bright stars to obtain highly accurate stellar parameters, including masses and ages. The combination of bright targets and asteroseismology results in high accuracy for the bulk planet parameters: 2 %, 4–10 % and 10 % for planet radii, masses and ages, respectively. The planned baseline observing strategy includes two long pointings (2–3 years) to detect and bulk characterize planets reaching into the habitable zone (HZ) of solar-like stars and an additional step-and-stare phase to cover in total about 50 % of the sky. PLATO 2.0 will observe up to 1,000,000 stars and detect and characterize hundreds of small planets, and thousands of planets in the Neptune to gas giant regime out to the HZ. It will therefore provide the first large-scale catalogue of bulk characterized planets with accurate radii, masses, mean densities and ages. This catalogue will include terrestrial planets at intermediate orbital distances, where surface temperatures are moderate. Coverage of this parameter range with statistical numbers of bulk characterized planets is unique to PLATO 2.0. The PLATO 2.0 catalogue allows us to e.g.: - complete our knowledge of planet diversity for low-mass objects, - correlate the planet mean density-orbital distance distribution with predictions from planet formation theories,- constrain the influence of planet migration and scattering on the architecture of multiple systems, and - specify how planet and system parameters change with host star characteristics, such as type, metallicity and age. The catalogue will allow us to study planets and planetary systems at different evolutionary phases. It will further provide a census for small, low-mass planets. This will serve to identify objects which retained their primordial hydrogen atmosphere and in general the typical characteristics of planets in such low-mass, low-density range. Planets detected by PLATO 2.0 will orbit bright stars and many of them will be targets for future atmosphere spectroscopy exploring their atmosphere. Furthermore, the mission has the potential to detect exomoons, planetary rings, binary and Trojan planets. The planetary science possible with PLATO 2.0 is complemented by its impact on stellar and galactic science via asteroseismology as well as light curves of all kinds of variable stars, together with observations of stellar clusters of different ages. This will allow us to improve stellar models and study stellar activity. A large number of well-known ages from red giant stars will probe the structure and evolution of our Galaxy. Asteroseismic ages of bright stars for different phases of stellar evolution allow calibrating stellar age-rotation relationships. Together with the results of ESA’s Gaia mission, the results of PLATO 2.0 will provide a huge legacy to planetary, stellar and galactic science. [less ▲]

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See detail'What is an incident?': Conceptual Boundaries under the Microscope
Rossignol, Nicolas ULg

Scientific conference (2014, September 04)

Within the context of a nuclear facility, how can an event be qualified as an incident or not, depending on different definitions, either formal or corresponding to actors' own representations? In this ... [more ▼]

Within the context of a nuclear facility, how can an event be qualified as an incident or not, depending on different definitions, either formal or corresponding to actors' own representations? In this presentation, we show how different those definitions are, and we elaborate on the reasons why such a focus on conceptual boundaries is interesting in the context of "incident reporting". [less ▲]

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See detailTeaching Practices in Science: a Survey of Primary Teachers in the French Speaking Community of Belgium
Quittre, Valérie ULg; Meyer, Coralie; Monseur, Christian ULg

Conference (2014, September 04)

Since PISA 2000, the performance of 15 year-old students from French speaking Community of Belgium (FWB) in science is largely below the OECD average (OECD, 2002, 2004, 2007, 2010 and 2013). This low ... [more ▼]

Since PISA 2000, the performance of 15 year-old students from French speaking Community of Belgium (FWB) in science is largely below the OECD average (OECD, 2002, 2004, 2007, 2010 and 2013). This low level of performance is not really unexpected as it was already observed at grade 7 and grade 8 in TIMSS 1995 (Harmon, Smith & Martin, 1997). In mathematics and in reading, the average performance of the 15 year-olds do not significantly differ from the OECD mean. Can these differences in performance in comparison with the OECD means be partly attributed to the emphasis and importance of the respective intended and implemented curricula? Does the relative importance of science teaching differ between primary and secondary education? In this investigation, we make the assumptions that the problem already exists in primary education and persists in secondary education. Therefore, we will focus on primary education. Data will be mainly collected on opportunities to learn (OTL) for science education and on professional knowledge and teaching practices More precisely, these study intents to question teachers at grade 3 and grade 4 about their beliefs and practices in science. Do the primary teachers feel confident and comfortable with science knowledge and science teaching? What’s the effective learning time of our pupils in science? Can we identify patterns of teachers that current international research has shown to have a significant role in science education of pupils? [less ▲]

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See detailx
Dodeigne, Jérémy ULg

Conference (2014, September 04)

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See detailEtude de l'implication de cellulases dans la voie de biosynthèse de cellulose chez les bactéries
Delsaute, Maud ULg

Doctoral thesis (2014)

By definition, cellulases are enzymes that catalyze the degradation of cellulose. However, their involvement in cellulose biosynthesis by bacteria and plants has been reported, although their exact ... [more ▼]

By definition, cellulases are enzymes that catalyze the degradation of cellulose. However, their involvement in cellulose biosynthesis by bacteria and plants has been reported, although their exact contribution remains unclear. In the present study, we have investigated the involvement of cellulases from glycoside hydrolase family 5 (GH5) in cellulose synthesis. In particular, we have functionally and structurally characterized the Ps_Cel5A cellulase from Pseudomonas stutzeri and its metagenome-derived homolog RBcel1, which both belong to the GH5 family and are suspected to be involved in cellulose biosynthesis. In addition, we have also compared these enzymes with the well-characterized Ta_Cel5A cellulase from the cellulolytic fungus Thermoascus aurantiacus. The first part of the work was devoted to the description of the tridimensional structure of RBcel1, in comparison with other glycoside hydrolases from GH5. In the second part of the study, we focused on the functional and structural comparison between RBcel1, Ps_CelA and Ta_Cel5A. Biochemical analysis has highlighted that, besides their hydrolytic activity, RBcel1 and Ps_Cel5A were able to catalyze transglycosylation in vitro. This synthesis reaction was not detected for Ta_Cel5A, which seemed to remain hydrolytic only. Determination of the structure of RBcel1 in complex with cellobiose has revealed distinct features in the aglycone substrate binding sites compared to Ta_Cel5A which could potentially explain the observed differences in their activities in vitro. Finally, the involvement of Ps_Cel5A in cellulose production by P. stutzeri was confirmed, by analysis the ability of P. stutzeri-ΔPs_Cel5A to produce the polymer. Complementation of this mutant strain by the three cellulases was also performed and discussed. [less ▲]

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See detailLes effets délétères métaboliques et oxydants induits lors d'un sepsis sur la fonction rénale
Quoilin, Caroline ULg

Doctoral thesis (2014)

Acute kidney injury (AKI) is a frequent complication of sepsis that can increase mortality as high as 70%. The pathophysiology of this kidney failure was previously believed to be secondary to decreased ... [more ▼]

Acute kidney injury (AKI) is a frequent complication of sepsis that can increase mortality as high as 70%. The pathophysiology of this kidney failure was previously believed to be secondary to decreased global renal perfusion causing hypoxia-induced injury. However, new research suggests this paradigm is overly simplistic, and injury is now considered multifactorial in origin. Mechanisms that contribute to kidney injury mainly include inflammation, alterations in microvascular renal blood flow and changes in bioenergetics. To study the mechanism of oxygen regulation in acute kidney injury during sepsis, we developed a sepsis-induced in vitro model using proximal tubular epithelial cells (HK-2) exposed to a bacterial endotoxin (lipopolysaccharide, LPS). Our first investigation, by using both high-resolution respirometry and electron spin resonance spectroscopy, showed that HK-2 cells exhibit a decreased oxygen consumption rate when treated with LPS. Surprisingly, this cellular respiration alteration persists even after the stress factor is removed. We suggested that this irreversible decrease in renal oxygen consumption after LPS challenge is related to a pathologic metabolic down-regulation such as a lack of oxygen utilization by cells for ATP production. In the long term, this metabolic disturbance leads cells to a predominantly apoptotic death. To confirm this hypothesis of cytopathic hypoxia, we demonstrated that this alteration in the renal respiratory function is mainly due to an impairment in the metabolic activity of HK-2 cell mitochondria. Following LPS treatment, the oxidative phosphorylation is interrupted because of the inhibition of cytochrome c oxidase activity. As a consequence, disruptions in the electron transport and the proton pumping across the system occur, leading to a decrease of the mitochondrial membrane potential, the release of apoptotic-inducing factors and a decrease in ATP production. To clarify the mechanism by which the LPS induces mitochondrial alterations, we studied the oxidative stress generation in HK-2 cells. Interestingly, we revealed that the induction of a cytosolic oxidative stress is an event that appears before mitochondrial dysfunction in the LPS-treated HK-2 cells. This primary redox state is notably due to the activation of the two enzymes NADPH oxidase 4 and inducible NO synthase. The simultaneous production of anion superoxide and nitric oxide strongly suggests the formation of peroxynitrite, a relative stable powerful oxidant that can diffuse through mitochondrial compartments and undergo cytotoxic reactions. To our knowledge, our model reveals for the first time the role of NADPH oxidase-derived cytosolic ROS in triggering tubular cell damage. Moreover, after being first target of the oxidative stress, mitochondria become in turn producer of reactive oxygen species that carry on mitochondrial dysfunction. It seems thus that a mechanism of oxidative stress-induced redox cycling is a main cause of the mitochondrial dysfunction of LPS-treated HK-2 cells. The role of oxidants in mitochondrial dysfunction was further confirmed by the use of iNOS inhibitors or antioxidants that preserve cytochrome c oxidase activity and block mitochondrial membrane potential dissipation. Overall, these results suggest that sepsis-induced AKI should not only be regarded as failure of energy status but also as an integrated response, including transcriptional events, ROS signaling, mitochondrial activity and metabolic orientation such as apoptosis. [less ▲]

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See detailUn référentiel de compétences pour la formation des architectes et après?
Scheffers, Patricia ULg

Scientific conference (2014, September 03)

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See detailPhysiopathology of cerebral palsy
VIELLEVOYE, Renaud ULg

Conference (2014, September 03)

Cerebral palsy describes a group of disorders of the development of movement and posture, causing activity limitation, that are attributed to nonprogressive disturbances that occurred in the developing ... [more ▼]

Cerebral palsy describes a group of disorders of the development of movement and posture, causing activity limitation, that are attributed to nonprogressive disturbances that occurred in the developing fetal or infant brain. The vulnerability of different brain structures and types of disability associated with CP are influenced by the gestational age at which brain development is altered. Understanding the pathophysiology of CP is crucial for the development of neuroprotective strategies. In the first trimester of gestation, genetic disorders, infectious and toxic diseases explain the vast majority of lesions. In the preterm newborn, neuroinflammation and anoxo-ischemia induce activation of the microglia and a maturational blockade of oligodendrocytes disrupting the developmental program of white matter. In term infants, hypoxic-ischemic encephalopathy is the consequence of the excitotoxic cascade leading to cortical and/or basal ganglia lesions. Clinical disabilities are the consequence of these lesions modulated by cerebral plasticity process. [less ▲]

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