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See detailA hydrochemical - isotopic approach for assessing factors controlling the regional pollution of an urban aquifer
Gesels, Julie ULg; Orban, Philippe ULg; Popescu, Ileana-Cristina et al

Poster (2015, June 24)

The alluvial aquifer of the Meuse River is contaminated at regional scale in the urbanized and industrialized area of Liège in Belgium, in particular inorganics pollutants such as sulfate, nitrate and ... [more ▼]

The alluvial aquifer of the Meuse River is contaminated at regional scale in the urbanized and industrialized area of Liège in Belgium, in particular inorganics pollutants such as sulfate, nitrate and ammonium. The sources of those contaminants are numerous: brownfields, urban waste water, subsurface acid mine drainage from former coal mines, atmospheric deposits related to former pollutants emissions in the atmosphere ... Sulfate, nitrate and ammonium are both typical pollutants of the aquifer and tracers of the possible pollution sources. In the Water Framework Directive context, a detailed hydrogeochemical characterization of groundwater was performed. The aim is to determine the origin of the inorganic contaminations, the main processes contributing to poor groundwater quality and the spatial extent of the contaminations. A large hydrochemical sampling campaign was performed, based on 71 selected representative sampling locations, to better characterize the different vectors (end-members) of contamination of the alluvial aquifer and their respective contribution to groundwater contamination in the area. Groundwater samples were collected and analyzed for major and minor compounds and metallic trace elements. The analyses also include stable isotopes in water, sulfate, nitrate, ammonium, dissolved inorganic carbon, boron and strontium. Different hydrogeochemical approaches are combined to obtain a global understanding of the hydrogeochemical processes at regional scale. Hydrochemical interpretations are based on classical diagrams, spatial distribution maps, geochemical equations, multivariate statistics such as self-organizing maps and isotopic analyses. With this combined approach, the location of the contaminant sources and most contaminated sectors of the alluvial aquifer together with a better understanding of geochemical processes involved are obtained. Redox processes strongly influence the composition of groundwater, specifically for compounds degrading the quality of groundwater in the area (sulfate, nitrate and ammonium). The highest concentrations of sulfate can be associated with the post-mining stage in the acid mine drainage process. Various reactions involving nitrogen compounds have been identified and allow a better understanding of causes of high concentrations of ammonium and nitrate. Denitrification and sulphate reduction are also demonstrated based on isotopic ratios. [less ▲]

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See detailWood Acid Hydrolysate as a Feedstock for Chlorella Growth
Miazek, Krystian ULg; Goffin, Dorothée ULg; Richel, Aurore ULg et al

Scientific conference (2015, June 24)

In this work, the effect of beech (Fagus sylvatica) wood acid hydrolysate on growth of Chlorella sorokin-iana was evaluated. Experiments carried out in this study show that neutralized wood acid ... [more ▼]

In this work, the effect of beech (Fagus sylvatica) wood acid hydrolysate on growth of Chlorella sorokin-iana was evaluated. Experiments carried out in this study show that neutralized wood acid hydrolysate can vastly improve Chlorella growth, due to the presence of organic carbon. However, simultaneously the suppression of Chlorella growth at the onset of cultivation was observed, presumably due to inhibitory substances, and this effect was more pronounced with the increase of hydrolysate dosage. Beech wood acid hydrolysate can be a valuable feedstock to stimulate Chlorella growth, on condition that inhibitory level of hydrolysate loading is avoided. [less ▲]

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See detailSuperstudio’s Dystopian Tales: Textual and Graphic Practice as Operational Method
Prina, Daniela ULg

in Writing Visual Culture (2015), 6

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See detailIUVS periapse observations of Mars’ Nitric Oxide
Stiepen, Arnaud ULg; IUVS team

Scientific conference (2015, June 24)

Detailed reference viewed: 17 (0 ULg)
See detailAlma @ ULg : Déploiement d'Alma à l'Université de Liège
Renaville, François ULg

Conference given outside the academic context (2015)

Présentation du projet de migration de Aleph et SFX vers le système de gestion de bibliothèque (SGB) Alma d'août 2014 à février 2015.

Detailed reference viewed: 22 (1 ULg)
See detailPrimo dans le Cloud ?
Nabias, Laurent; Jestin, André; Renaville, François ULg

Conference given outside the academic context (2015)

Detailed reference viewed: 16 (3 ULg)
See detailAlma @ ULg : Retour d'expérience après 4 mois
Renaville, François ULg

Conference given outside the academic context (2015)

Présentation des 4 premiers mois d'expérience sur le système de gestion de bibliothèque (SGB) Alma.

Detailed reference viewed: 16 (2 ULg)
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See detailAging mechanisms in amorphous phase-change materials
Raty, Jean-Yves ULg; Zhang, wei; Luckas, Jennifer et al

in Nature Communications (2015), 6(7467), 1-8

Aging is a ubiquitous phenomenon in glasses. In the case of phase-change materials, it leads to a drift in the electrical resistance, which hinders the development of ultrahigh density storage devices ... [more ▼]

Aging is a ubiquitous phenomenon in glasses. In the case of phase-change materials, it leads to a drift in the electrical resistance, which hinders the development of ultrahigh density storage devices. Here we elucidate the aging process in amorphous GeTe, a prototypical phase-change material, by advanced numerical simulations, photothermal deflection spectroscopy and impedance spectroscopy experiments. We show that aging is accompanied by a progressive change of the local chemical order towards the crystalline one. Yet, the glass evolves towards a covalent amorphous network with increasing Peierls distortion, whose structural and electronic properties drift away from those of the resonantly bonded crystal. This behaviour sets phase-change materials apart from conventional glass-forming systems, which display the same local structure and bonding in both phases [less ▲]

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See detailHölder Continuity and Wavelets
Simons, Laurent ULg

Doctoral thesis (2015)

There exist a lot of continuous nowhere differentiable functions, but these functions do not have the same irregularity. Hölder continuity, and more precisely Hölder exponent, allow to quantify this ... [more ▼]

There exist a lot of continuous nowhere differentiable functions, but these functions do not have the same irregularity. Hölder continuity, and more precisely Hölder exponent, allow to quantify this irregularity. If the Hölder exponent of a function takes several values, the function is said multifractal. In the first part of this thesis, we study in details the regularity and the multifractality of some functions: the Darboux function, the Cantor bijection and a generalization of the Riemann function. The theory of wavelets notably provides a tool to investigate the Hölder continuity of a function. Wavelets also take part in other contexts. In the second part of this thesis, we consider a nonstationary version of the classical theory of wavelets. More precisely, we study the nonstationary orthonormal bases of wavelets and their construction from a nonstationary multiresolution analysis. We also present the nonstationary continuous wavelet transform. For some irregular functions, it is difficult to determine its Hölder exponent at each point. In order to get some information about this one, new function spaces based on wavelet leaders have been introduced. In the third and last part of this thesis, we present these new spaces and their first properties. We also define a natural topology on them and we study some properties. [less ▲]

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See detailAging mechanisms in amorphous phase-change materials
Raty, Jean-Yves ULg

Conference (2015, June 23)

Aging phenomena are common to all amorphous structures, but of special importance in phase change materials (PCM) since it impedes the realization of multi-level memories. Different interpretations have ... [more ▼]

Aging phenomena are common to all amorphous structures, but of special importance in phase change materials (PCM) since it impedes the realization of multi-level memories. Different interpretations have been proposed, but we focus here on the structural relaxation of amorphous GeTe, chosen because it is the simplest system that is representative of the wider class of GST alloys, lying along the GeTe-Sb2Te3 composition line of the GeSbTe phase diagram. The direct melt-and-quench DFT based Molecular Dynamics approach leads to models with a few hundred atoms, and, hence a small number of atomic environments. Here we sample a large number of local atomic environments, and bonding schemes, by chemically substituting different alloys to favor different local atomic structures. This enables spanning a larger fraction of the configuration space relevant to aging. GST alloys are known to display complex bonding that does not follow the chemist’s “octet-rule”. This lead to many controversies, especially concerning the local structure around Ge atoms. We overcome this problem by using state of the art non local DFT-MD, including the so-called van der Waals corrections. This leads to more clearly defined environments that are thoroughly analyzed. We can then identify their fingerprints in the available structural experimental data and assess their stability to find the driving forces leading to the structural relaxation. The calculated electronic properties nicely match the most recent photothermal deflection spectroscopy experiments. Our results support a model of the amorphous phase and its time evolution that involves an evolution of the local (chemical) order towards that of the crystal (by getting rid of homopolar bonds), and an evolution of its electronic properties that drift away from those of the crystal, driven by an increase of the Peierls-like distortion of the local environments in the amorphous [1]. [1] J.Y Raty, W. Zhang, J. Luckas, C. Chen, R. Mazzarello, C. Bichara and M. Wuttig, Nature Comm. To appear. [less ▲]

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Peer Reviewed
See detailDistributive contact lattices with nontangential part-of relations
Raskin, Julien ULg

Conference (2015, June 23)

In a Boolean algebra, the "contact" and "nontangential part-of" relations are linked and interdefinable thanks to the complement. These relations yield on the Stone dual of the algebra two closed ... [more ▼]

In a Boolean algebra, the "contact" and "nontangential part-of" relations are linked and interdefinable thanks to the complement. These relations yield on the Stone dual of the algebra two closed relations that appear to be the same. In a distributive lattice, the contact and nontangential part-of relations also yield dual closed relations on the Priestley dual. However, as the link between them is lost, these relations are not equal anymore. We explore the conditions linking the contact and nontangential part-of relations one should add in order to recover these relations knowing the intersection of their dual. [less ▲]

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See detailFULLY AUTOMATED ELECTROPHORETICALLY MEDIATED MICROANALYSIS SYSTEM FOR CYP1A1 ACTIVITY MONITORING
Farcas, Elena ULg; Servais, Anne-Catherine ULg; Lamalle, Caroline ULg et al

Poster (2015, June 23)

Introduction Since the efficacy and toxicity of drugs are closely related to their pharmacokinetics, a good understanding of metabolic pathways is important at an early stage of development. The ... [more ▼]

Introduction Since the efficacy and toxicity of drugs are closely related to their pharmacokinetics, a good understanding of metabolic pathways is important at an early stage of development. The identification of the enzymes involved in drug metabolism is thus of critical importance for the design of further clinical studies. The availability of specifically expressed human CYPs, namely supersomes, allows the investigation of the contribution of a single metabolic enzyme to the biotransformation pathway of the compound under investigation. CYP1A1, a member of the cytochrome P450 superfamily, was studied in this project. Interestingly, it has been described to be over expressed in various types of cancer. Consequently, CYP1A1 has emerged as a particularly interesting target for cancer therapy. Methods All the experiments were carried out on a HP3DCE system equipped with an on-column DAD. The EMMA procedure was performed by injecting a plug containing CYP1A1 supersomes, followed by a plug that contained the co-factor and the substrate, then another plug of CYP1A1 supersomes. The reaction was triggered by the application of a voltage switch. The voltage was then turned off to allow the metabolic reaction to occur. The separation of the components was then performed at -25 kV. Results The present study describes the development of a fully automatized in-capillary method to follow metabolization of 7-hydroxycoumarin and screen CYP1A1 inhibitors. After preliminary studies, satisfying results were obtained using CYP1A1 at a concentration of 200 pmol/mL, while the incubation time was settled to 15 min. Equal reactant plugs were injected at -50 mbar for 6 sec. The short-end injection performed gave rise to a baseline separation of the molecules (substrate, product, CYP1A1 and NADPH) in less than 2 minutes. Adequate plugs overlap was obtained using electrophoretic mixing. The DoE performed highlighted that the voltage switch has a great impact on the metabolite formation. The amount of product obtained in the optimal conditions was found to be comparable to the one detected after conventional off-line metabolization. Besides the interest of developing an automatized CE approach for metabolisation studies, we also wanted to investigate the potentiality of this approach to screen CYP1A1 inhibitors. The ability of our system to monitor CYP1A1 inhibition was undertaken with apigenin, a well-known inhibitor. It is noteworthy that the compatibility of our system with MEKC ensures its applicability to a large variety of molecules. Novel aspect Monitoring CYP1A1 activity using a rapid and fully automated EMMA method that could be used for new anticancer agents screening. [less ▲]

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See detailQuality and Innovation, key factors for laboratory evolution
HUYNEN, Pascale ULg

Conference (2015, June 23)

Today the laboratory has to face many challenges: constant increase of number of tests to be run, private labs that competes in reaching a lower TAT, disease outbreak that arises without the possibility ... [more ▼]

Today the laboratory has to face many challenges: constant increase of number of tests to be run, private labs that competes in reaching a lower TAT, disease outbreak that arises without the possibility of human control, like the recent mumps outbreak, the need to provide fast results in case of emergency or for transplants, the request to keep high level of traceability of all results, the accreditation of the lab are just some examples. With the same number of operators, year after year, new clinical needs have to be satisfied in a timely manner, with efficiency and without compromise in quality. The solution for us has been, across several year, to look for innovation. Moving from Elisa to chemiluminescence and therefore from open systems to close and state of the art systems, it has allowed us to face with success all those challenges. The availability of more and more infectious disease markers on fully automated analyzers, with good level of performance, have let us to cope with all the changes that have happened across more than a decade. Indeed innovation and quality are fundamental to support properly the laboratory evolution that occurred since today and it is still occurring. Innovation in our laboratory it is also represented by the introduction of automatized tests not only on serum and plasma specimens, but also on CSF (for Lyme disease diagnosis) and on stool matrix. In 2013 in fact we have introduced, among the assays already tested in our laboratory, two assays performed on this matrix, the C. difficile Toxin A&B and GDH, due to the possibility offered by the LIAISON® systems to run all of them on the same serology platform, without crosscontamination. New markers will be available in the near future, and our laboratory will be always able to meet the next clinical needs. [less ▲]

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See detailEnquêter auprès des sourds. Implications éthiques, méthodologiques et statistiques de l’adaptation d’enquêtes d’opinion au public sourd.
Fontaine, Sébastien ULg

Doctoral thesis (2015)

For technical and logistical reasons, disabled people (and especially deaf people) are excluded from opinion surveys. This leads to the situation that deaf people remain unrepresented in the statistical ... [more ▼]

For technical and logistical reasons, disabled people (and especially deaf people) are excluded from opinion surveys. This leads to the situation that deaf people remain unrepresented in the statistical tendencies emerging from such quantitative opinion surveys. This observation is at the heart of the research presented in this work. This thesis consists of four chapters, each one tackling specific aspects of the implications of this lack of representation of deaf people in opinion surveys. The first chapter gives a short description of the situation of deaf people, from a sociological point of view. The second chapter discusses the moral and ethical issues raised by the lack of representation of deaf people in opinion surveys, in a more philosophical perspective. In the third chapter, we present new adapted methods making it possible to conduct opinion surveys among deaf people. Thanks to a new type of electronic questionnaire including sign language videos, we more specifically show how deaf people can be surveyed for different purposes. On the basis of these new techniques, the final chapter offers a commented statistical analysis of the deaf people situation in French-speaking Belgium. [less ▲]

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See detailThe European Parliament within the global governance of culture: voice and influence
Vlassis, Antonios ULg

Conference (2015, June 23)

Abstract: The paper deals with the international actorness of the European Parliament (EP) within the global governance of cultural industries, and in particular with its ability to promote the ... [more ▼]

Abstract: The paper deals with the international actorness of the European Parliament (EP) within the global governance of cultural industries, and in particular with its ability to promote the Convention on diversity of cultural expressions (CDCE) on its international relations and on the EU international agreements. In this respect, it attempts to analyse empirically not only the EP’s interests and strategies about the CDCE and its place within the EU external relations, but also the ways that the EP shapes the process of the global governance of cultural industries, challenging its political asymmetries and hierarchies. In this sense, the paper draws five main conclusions: a. it illustrates a recent multiplication of EP resolutions and of written parliamentary questions towards the culture in EU external relations, and especially the link between trade agreements and culture; b. the EP seeks to promote a more normative position for the global governance of cultural industries, taking cultural concerns seriously into account; c. the negotiations between EU and United States reveal that the EP does not follow the pro-liberalization agenda of the European Commission and especially of DG Trade. On the contrary, the EP sided with the French government and the cultural professional organizations and it interpreted the CDCE as a normative tool protecting and promoting the cultural policies in the context of the trade negotiations; d. the EP’s votes towards the culture in EU external relations follow more the national cleavages existing within the European Council rather than a left-right divide, showing that the national lines seem to be a substantial factor in order to understand the EP’s preferences; e. despite the establishment of an international normative framework towards the cultural sector and the inclusion of the culture as a component of the EU foreign policy, the EP’s diplomacy has not yet fully integrated the culture among its priorities. In this sense, the different aspects of the cultural sector such as the cultural and creative industries or the tangible, natural and intangible cultural heritage are absent from the discussions of the EP with national and other regional parliaments. [less ▲]

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See detailLearning Artificial Intelligence in Large-Scale Video Games: A First Case Study with Hearthstone: Heroes of Warcraft
Taralla, David ULg

Master's dissertation (2015)

Over the past twenty years, video games have become more and more complex thanks to the emergence of new computing technologies. The challenges players face now involve the simultaneous consideration of ... [more ▼]

Over the past twenty years, video games have become more and more complex thanks to the emergence of new computing technologies. The challenges players face now involve the simultaneous consideration of many game environment variables — they usually wander in rich 3D environments and have the choice to take numerous actions at any time, and taking an action has combinatorial consequences. However, the artificial intelligence (AI) featured in those games is often not complex enough to feel natural (human). Today's AI is still most of the time hard-coded, but as the game environments become increasingly complex, this task becomes exponentially difficult. To circumvent this issue and come with rich autonomous agents in large-scale video games, many research works already tried and succeeded in making video game AI learn instead of being taught. This thesis does its bit towards this goal. In this work, supervised learning classification based on extremely randomized trees is attempted as a solution to the problem of selecting an action amongst the set of available ones in a given state. In particular, we place ourselves in the context where no assumptions are made on the kind of actions available and where action simulations are not possible to find out what consequences these have on the game. This approach is tested on the collectible card game Hearthstone: HoW, for which an easily-extensible simulator was built. Encouraging results were obtained when facing Nora, the resulting Mage agent, against random and scripted (medium-level) Mage players. Furthermore, besides quantitative results, a qualitative experiment showed that the agent successfully learned to exhibit a board control behavior without having been explicitly taught to do so. [less ▲]

Detailed reference viewed: 79 (8 ULg)