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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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See detailNarration et jeu vidéo. Pour une exploration des univers fictionnels
Barnabé, Fanny ULg

Book published by Bebooks (2014)

Un jeu vidéo peut-il raconter une histoire ? De quels moyens spécifiques dispose-t-il pour y parvenir ? Classique en game studies, la question de la narration dans le jeu vidéo continue d’interpeller ... [more ▼]

Un jeu vidéo peut-il raconter une histoire ? De quels moyens spécifiques dispose-t-il pour y parvenir ? Classique en game studies, la question de la narration dans le jeu vidéo continue d’interpeller chercheurs, consommateurs et professionnels de l’industrie, après avoir participé à la structuration du champ de recherche ces quinze dernières années. Partant de ces questions, l’ouvrage Narration et jeu vidéo. Pour une exploration des univers fictionnels propose un modèle explicatif fondé sur la notion riche d’univers fictionnel. Sur cette base, il propose de penser la narration vidéoludique hors des cadres traditionnels et de la concevoir comme un dispositif non figé, ouvert à l’infinité d’actualisations possibles que représente chaque partie jouée. Alternant réflexion théorique et analyses de cas, ce livre se destine tant au chercheur qu’au game designer ou au joueur désireux de réfléchir sur sa pratique. Ce livre a été lauréat du prix BiLA en 2012 (Bibliothèque des Littératures d'Aventures). [less ▲]

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See detailHow (not) to perform ecosystem service valuation - Pricing Gorillas in the Mist -
Boeraeve, Fanny ULg; Dendoncker, Nicolas; Jacobs, Sander et al

in Biodiversity and Conservation (2014)

Monetary valuation of ecosystem services (ES) is gaining growing interest in scientific papers, policies and awareness-raising documents for its potential as a communication tool illustrating the societal ... [more ▼]

Monetary valuation of ecosystem services (ES) is gaining growing interest in scientific papers, policies and awareness-raising documents for its potential as a communication tool illustrating the societal importance of biodiversity. However, simultaneously, its limitations are increasingly discussed in the literature. In this paper we argue that monetary valuation of ES should be seen as representing only one component of ES valuations. We provide basic standards to ensure integrated approaches to ES valuation that can effectively contribute to preserving cultural and biological diversity by acknowledging boundaries to resource exploitation and by building on the various interests and socio-cultural values of involved stakeholders. We base our discussion on a recent study that assesses the economic value of the world-famous Virunga National Park in the Democratic Republic of Congo, home to some of the last mountain gorillas (Gorilla beringei beringei). We alert against some ES monetary valuation that narrowly frames biodiversity conservation in terms of economic calculus and argue that subjugating conservation efforts to profit logics downplays the importance of intrinsic, symbolic and other non-economic values of biodiversity. We conclude by providing principles and methodological guidelines to enhance ES valuation as a tool to promote awareness rising for biodiversity conservation through the understanding the overall importance of biodiversity for human societies. [less ▲]

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See detailCompeting as a Luxury SME
Riguelle, France ULg; Van Caillie, Didier ULg

in Reinecke, Sven; Berghaus, Benjamin; Müller-Stewens, Günter (Eds.) The Management of Luxury (2014)

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See detailMineralogy of fine particles in slurry from multispectral imaging
Leroy, Sophie ULg; Dislaire, Godefroid ULg; Barnabé, Pierre ULg et al

Conference (2014, September 02)

Quantitative mineralogy of fine particles in slurry from multispectral imaging Sophie Leroy, Godefroid Dislaire, Pierre Barnabé and Eric Pirard Mineral processing especially in its final stages relies ... [more ▼]

Quantitative mineralogy of fine particles in slurry from multispectral imaging Sophie Leroy, Godefroid Dislaire, Pierre Barnabé and Eric Pirard Mineral processing especially in its final stages relies heavily on the differential behavior of particles in pulps. In order to monitor hydrocyclones and flotation cells in almost real time, it is important to develop at line particle characterization providing information on particle distribution but also mineralogy. A sampling device has been elaborated based on a flow cell with variable wall spacing linked to a high pressure peristaltic pump. This setup allows for dispersion and dilution of the mineral slurry into the cell. Depending on the ore or gangue minerals to be controlled, particles can be imaged either in diffuse reflectance or in transmittance mode. A simple multispectral imaging module has been designed to acquire images at eight different wavelengths. The design is based on a series of dichroic filters thereby avoiding any moving part and enabling a very fast acquisition of multispectral images. Imaging artifacts due, among others, to specular reflectance from the glass window are minimized. Multispectral classification is used to outline particles appearing in the field of view and to qualify their main mineral component. In particular, areas reflecting a meaningful and discriminative spectrum are identified and compared to a multispectral database. The database is continuously enriched through testing of pure mineral particles under similar pulp conditions (dilution, grain size,…). Results of final classification are compared to the modal analysis obtained from polished blocks and conventional reflected light microscopy. The technology developed in this work sets the basis for at line monitoring of ore slurries with reasonably simple mineralogy. Extension of the spectral range is being considered for future developments. [less ▲]

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See detailFrom geometallurgy to ecometallurgy:Building mines for the future
Pirard, Eric ULg

Conference (2014, September 02)

geometallurgy will become the central pivot of a successful mining operation. Recently, Europe has awakened from a long period of lethargy in the raw materials sector. A series of important initiatives ... [more ▼]

geometallurgy will become the central pivot of a successful mining operation. Recently, Europe has awakened from a long period of lethargy in the raw materials sector. A series of important initiatives inspired by the European Innovation Partnership (EIP) have paved the way for more intense cooperation between industry, research centres and universities. Among these, the establishment of a Knowledge Innovation Community (KIC) in 2015 will definitely boost innovation and education in the sector. Interestingly, EIP addresses the whole value chain and considers mining, recycling and substitution as essential pillars of the raw materials policy. This vision strengthens the role of geometallurgy but also brings up the need for a close dialogue between mineralogists, metallurgists and product designers. Microelectronics and nanotechnologies are ubiquitous in our technologies and have greatly improved their functionality, but they have also made recycling and efficient recovery of metals a tough technical challenge. Our urban mines formed by the accumulation of end-of-life products should be scrutinized from now on using an ecometallurgical approach whereby important questions should be addressed such as: 1. Metal concentrations: Is the metal grade high enough to pay for recycling? Does the manufacturer help to maintain grades above a technological cut-off? 2. Metal speciation: Under which form (alloy, salt, organic compound,…) is the metal present? Is there a processing technology available to separate these species? 3. Metal paragenesis: What are the metal assemblages found in the product? Will it be feasible to separate those metals and at what costs? Are there penalty or contaminating elements associated? 4. Textural assemblage: How will the product behave during dismantling? Is it realistic to liberate a given component? What comminution strategy will be needed to achieve phase liberation? 5. Reserve estimation: What are the tonnages expected for this kind of product? Can selective collection be organised? 6. Homogeneity: What will the next generation of products look like? Should one expect strong differences in concentration, speciation, paragenesis, etc.? Will this kind of product be blended with others during collection? How will this impact on downstream recycling? Ecometallurgy, as introduced here, is essentially about establishing a dialogue with product designers and material scientists to make sure that, once unearthed, metals will remain easily and sustainably available for the future generations. Geologists and mineralogists, even though generally kept away from the synthetic materials, could greatly contribute to this progress by bringing their expertise in dealing with complex and variable orebodies of the future. [less ▲]

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See detailCost monitoring to promote the value added for clam raising farmers in the Northern area of Vietnam
Bui Thi, Nga; Tran Thu, Hoai; Tran Huu, Cuong et al

Conference (2014, September 02)

Clam farming in coastal provinces of Vietnam has notably developed since the last decade. It generated high income, improve socio-economic development for many local communities. However, many clam ... [more ▼]

Clam farming in coastal provinces of Vietnam has notably developed since the last decade. It generated high income, improve socio-economic development for many local communities. However, many clam raising farms are facing difficulties of farm management, disease control, markets and systems of quality control. This research aims to study about the real situation of cost monitoring in the clam raising farms in the Northern area of Vietnam and suggest some recommendation for apply a suitable model for cost monitoring to promote the value added for farmers. The paper based on the semi-structure, standard questionnaires and PRA method to collect data from 89 clam raising farms in two coastal provinces (Nam Dinh and Thai Binh) in the Northern area of Vietnam in 2014. The findings show that clam raising provides farmers a chance of getting high income parallel with high risk. There were 32.15% surveyed farms got profit, 32.14% of them met the breakeven and 35.71% was lost. The study finds out four key factors affecting farms’ economic performance and efficiency. The first is capacity of farm cost control as the cost for clam raising was very high at 8,142 to 9,190 USD per ha. The second is the farmers’ experience, skill, technique and ability of risk control. The third is low, unstable market price and unsuitable market channel with the dominant of the traders. Final factors is the area and location of clam raising. Despite of these difficulties, 55.14% surveyed farms still want to expand their production, 25% of them will continue, and only 17.86% will stop or change to other activities. In order to promote the value added for clam raising farmers, cost control should be paid more attention, improvement of the farmers’ capacity is necessary, and market should be regarded. [less ▲]

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