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See detailAlgorithmic and Computational Advances for Fast Power System Dynamic Simulations
Aristidou, Petros ULg; Van Cutsem, Thierry ULg

in Proceedings of the IEEE PES General Meeting (2014, July 30)

In this paper, some algorithmic and computational advances are presented for power system dynamic simulations. The heart is a Schur-complement-based solution algorithm, stemming from domain decomposition ... [more ▼]

In this paper, some algorithmic and computational advances are presented for power system dynamic simulations. The heart is a Schur-complement-based solution algorithm, stemming from domain decomposition methods, applied to the differential-algebraic equation model. This algorithm is then accelerated computationally, by employing parallel computing techniques, and numerically, by exploiting time-scale decomposition and localization. Models of a real medium-scale system and a realistic large-scale test system are used for the performance evaluation of the proposed methods. [less ▲]

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See detailQuelle histoire pour les forêts d'Afrique centrale ?
Morin-Rivat, Julie ULg

Scientific conference (2014, July 24)

Conférence grand public sur les indicateurs de perturbations climatiques et anthropiques dans les forêts d'Afrique centrale.

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See detailGEOMETRICAL VALIDITY OF HIGH-ORDER PYRAMIDAL FINITE ELEMENTS
Johnen, Amaury ULg; Geuzaine, Christophe ULg

Conference (2014, July 24)

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See detailThe vegetative state/unresponsive wakefulness syndrome: a systematic review of prevalence studies
Van Erp, WS; Lavrijsen, JC; Van De Laar, FA et al

in European Journal of Neurology (2014)

One of the worst outcomes of acquired brain injury is the vegetative state, recently renamed ‘unresponsive wakefulness syndrome’ (VS/UWS). A patient in VS/UWS shows reflexive behaviour such as spontaneous ... [more ▼]

One of the worst outcomes of acquired brain injury is the vegetative state, recently renamed ‘unresponsive wakefulness syndrome’ (VS/UWS). A patient in VS/UWS shows reflexive behaviour such as spontaneous eye opening and breathing, but no signs of awareness of the self or the environment. We performed a systematic review of VS/UWS prevalence studies and assessed their reliability. Medline, Embase, the Cochrane Library, CINAHL and PsycINFO were searched in April 2013 for cross-sectional point or period prevalence studies explicitly stating the prevalence of VS/UWS due to acute causes within the general population. We additionally checked bibliographies and consulted experts in the field to obtain ‘grey data’ like government reports. Relevant publications underwent quality assessment and data-extraction. We retrieved 1032 papers out of which 14 met the inclusion criteria. Prevalence figures varied from 0.2 to 6.1 VS/UWS patients per 100 000 members of the population. However, the publications’ methodological quality differed substantially, in particular with regards to inclusion criteria and diagnosis verification. The reliability of VS/UWS prevalence figures is poor. Methodological flaws in available prevalence studies, the fact that 5/14 of the studies predate the identification of the minimally conscious state (MCS) as a distinct entity in 2002, and insufficient verification of included cases may lead to both overestimation and underestimation of the actual number of patients in VS/UWS. [less ▲]

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See detailLiver proteomic response to hypertriglyceridemia in human-apolipoprotein C-III transgenic mice at cellular and mitochondrial compartment levels
Ehx, Grégory ULg; Gerin, Stéphanie ULg; Mathy, Grégory et al

in Lipids in Health and Disease (2014), 13

Background: Hypertriglyceridemia (HTG) is defined as a triglyceride (TG) plasma level exceeding 150 mg/dl and is tightly associated with atherosclerosis, metabolic syndrome, obesity, diabetes and acute ... [more ▼]

Background: Hypertriglyceridemia (HTG) is defined as a triglyceride (TG) plasma level exceeding 150 mg/dl and is tightly associated with atherosclerosis, metabolic syndrome, obesity, diabetes and acute pancreatitis. The present study was undertaken to investigate the impact of hypertriglyceridemia on the mitochondrial, sub-mitochondrial and cellular proteomes in the hepatocytes of a hypertriglyceridemic transgenic mouse model overexpressing the human apolipoproteinC-III. Methods: Quantitative comparative proteomics (2D-DIGE) was carried out in both “low-expressor” (LE) and “high-expressor” (HE) mice, respectively exhibiting moderate and severe HTG, to characterize the effect of the TG plasma level on the proteomic response. Results: The mitoproteome analysis revealed the occurrence of a large-scale adaptation in transgenic mice consisting of a general down-regulation of matricial proteins and up-regulation of inner membrane proteins. Remarkably, the magnitude of these proteomic changes appears to strongly depend on the TG plasma level. Altogether, our different analyses indicate that, in HE mice, the capacity of several metabolic pathways is altered to promote the availability of acetyl-CoA, glycerol-3-phosphate, ATP and NADPH for de novo TG biosynthesis. The up-regulation of several cytosolic ROS detoxifying enzymes also tend to confirm that the cytoplasm of HTG mice is subjected to oxidative stress as previously stated. The up-regulation of cytosolic ferritin indicates that iron over-accumulation could take place in the cytosol of HE mice hepatocytes and contribute to (i) enhance oxidative stress and (ii) promote cellular proliferation. Conclusions: The present analyses demonstrate that important TG dose-responsive metabolic adaptations are set up in human apolipoproteinC-III-overexpressing mice. Our results indicate that these adaptations could support the higher TG production rates which have been previously reported in this HTG model, and also suggest that cytosolic oxidative stress may result from FFA over-accumulation, iron overload and enhanced activity of some ROS-producing catabolic enzymes. [less ▲]

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See detailShort Prime Quadratizations of Cubic Negative Monomials
Crama, Yves ULg; Rodriguez Heck, Elisabeth ULg

E-print/Working paper (2014)

Pseudo-Boolean functions naturally model problems in a number of different areas such as computer science, statistics, economics, operations research or computer vision, among others. Pseudo-Boolean ... [more ▼]

Pseudo-Boolean functions naturally model problems in a number of different areas such as computer science, statistics, economics, operations research or computer vision, among others. Pseudo-Boolean optimization (PBO) is NP-hard, even for quadratic polynomial objective functions. However, much progress has been done in finding exact and heuristic algorithms for the quadratic case. Quadratizations are techniques aimed at reducing a general PBO problem to a quadratic polynomial one. Quadratizing single monomials is particularly interesting because it allows quadratizing any pseudo-Boolean function by termwise quadratization. A characterization of short quadratizations for negative monomials has been provided. In this report we present a proof of this characterization for the case of cubic monomials, which requires a different analysis than the case of higher degree. [less ▲]

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See detailDetermination of the ruminant origin of bone particles using fluorescence in situ hybridization (FISH).
Lecrenier, Marie-Caroline ULg; Ledoux, Quentin; Berben, Gilbert et al

in Scientific reports (2014), 4

Molecular biology techniques such as PCR constitute powerful tools for the determination of the taxonomic origin of bones. DNA degradation and contamination by exogenous DNA, however, jeopardise bone ... [more ▼]

Molecular biology techniques such as PCR constitute powerful tools for the determination of the taxonomic origin of bones. DNA degradation and contamination by exogenous DNA, however, jeopardise bone identification. Despite the vast array of techniques used to decontaminate bone fragments, the isolation and determination of bone DNA content are still problematic. Within the framework of the eradication of transmissible spongiform encephalopathies (including BSE, commonly known as "mad cow disease"), a fluorescence in situ hybridization (FISH) protocol was developed. Results from the described study showed that this method can be applied directly to bones without a demineralisation step and that it allows the identification of bovine and ruminant bones even after severe processing. The results also showed that the method is independent of exogenous contamination and that it is therefore entirely appropriate for this application. [less ▲]

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See detailInventory-routing problem with pickups and deliveries of RTI in closed-loop supply chain
Iassinovskaia, Galina; Limbourg, Sabine ULg; Riane, Fouad

Conference (2014, July 17)

Reducing environmental impact, related regulations and potential for operational benefits are the main reasons why companies share their Returnable Transport Items (RTIs) among different partners of a ... [more ▼]

Reducing environmental impact, related regulations and potential for operational benefits are the main reasons why companies share their Returnable Transport Items (RTIs) among different partners of a closed-loop supply chain. This research deals with an inventory-routing problem with pickups and deliveries of RTIs. A mixed-integer linear program is developed and tested on small instances. To handle realistic large size problems, a clustering algorithm is coupled with a simulation model. This hybrid heuristic allows assessing the benefits of information and RTIs sharing among partners. [less ▲]

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See detailNumerical modelling of mirror nozzle flow
De Cock, Nicolas ULg; Massinon, Mathieu ULg; Mercatoris, Benoît ULg et al

Conference (2014, July 15)

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See detailAssessing spatiotemporal variability and trends (2000-2013) of modeled and measured Greenland Ice Sheet albedo
Alexander, P.; Tedesco, M.; Fettweis, Xavier ULg et al

in Cryosphere Discussions (The) (2014), 8

Accurate measurements and simulations of Greenland Ice Sheet (GrIS) surface albedo are essential, given the crucial role of surface albedo in modulating the amount of absorbed solar radiation and ... [more ▼]

Accurate measurements and simulations of Greenland Ice Sheet (GrIS) surface albedo are essential, given the crucial role of surface albedo in modulating the amount of absorbed solar radiation and meltwater production. In this study, we assess the spatio-temporal variability of GrIS albedo (during June, July, and August) for the period 2000–2013. We use two remote sensing products derived from data collected by the Moderate Resolution Imaging Spectroradiometer (MODIS), as well as outputs from the Modèle Atmosphérique Régionale (MAR) regional climate model (RCM) and data from in situ automatic weather stations. Our results point to an overall consistency in spatiotemporal variability between remote sensing and RCM albedo, but reveal a difference in mean albedo of up to ~0.08 between the two remote sensing products north of 70° N. At low elevations, albedo values simulated by the RCM are positively biased with respect to remote sensing products and in situ measurements by up to ~0.1 and exhibit low variability compared with observations. We infer that these differences are the result of a positive bias in simulated bare-ice albedo. MODIS albedo, RCM outputs and in situ observations consistently point to a~decrease in albedo of −0.03 to −0.06 per decade over the period 2003–2013 for the GrIS ablation zone (where there is a net loss of mass at the GrIS surface). Nevertheless, satellite products show a~decline in albedo of −0.03 to −0.04 per decade for regions within the accumulation zone (where there is a net gain of mass at the surface) that is not confirmed by either the model or in situ observations. [less ▲]

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See detailHigher Symmetries of the conformal Laplacian
Radoux, Fabian ULg

Conference (2014, July 14)

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See detailOptimization of the service start time for an elementary shortest path problem with time windows
Arda, Yasemin ULg; Crama, Yves ULg; Kucukaydin, Hande ULg

E-print/Working paper (2014)

We investigate an elementary shortest path problem with resource constraints where a single capacitated vehicle, initially located at a depot, must serve a set of customers while respecting their ... [more ▼]

We investigate an elementary shortest path problem with resource constraints where a single capacitated vehicle, initially located at a depot, must serve a set of customers while respecting their individual time windows. When the vehicle visits a customer, it delivers the customer's demand and collects a revenue in return for the delivery. The vehicle can start its trip at any desired time. The transportation cost is a function of both the total distance traveled and the duration of the assigned trip. The objective is to determine the service start time from the depot, the subset of customers to be served, and the trip to be performed so as to minimize the total loss, which is calculated as the di erence between the transportation cost and the revenue collected from the customers. We develop two exact dynamic programming algorithms which can deal with an in nite number of Pareto-optimal states arising from the fact that the starting time and the duration of the trip act like continuous decision variables. We report computational results obtained with these algorithms and with a faster heuristic for the elementary shortest path problem. We also examine the performance of these algorithms when they are used to solve the pricing subproblem arising in the framework of a column generation algorithm for a related vehicle routing problem with time windows. [less ▲]

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See detailEffect of lignocellulose related compounds on microalgae growth and product biosynthesis: a review
Miazek, Krystian ULg; Remacle, Claire ULg; Richel, Aurore ULg et al

in Energies (2014), 7(2014), 4446-4481

Microalgae contain valuable compounds that can be harnessed for industrial applications. Lignocellulose biomass is a plant material containing in abundance organic substances such as carbohydrates ... [more ▼]

Microalgae contain valuable compounds that can be harnessed for industrial applications. Lignocellulose biomass is a plant material containing in abundance organic substances such as carbohydrates, phenolics, organic acids and other secondary compounds. As growth of microalgae on organic substances was confirmed during heterotrophic and mixotrophic cultivation, lignocellulose derived compounds can become a feedstock to cultivate microalgae and produce target compounds. In this review, different treatment methods to hydrolyse lignocellulose into organic substrates are presented first. Secondly, the effect of lignocellulosic hydrolysates, organic substances typically present in lignocellulosic hydrolysates, as well as minor co-products, on growth and accumulation of target compounds in microalgae cultures is described. Finally, the possibilities of using lignocellulose hydrolysates as a common feedstock for microalgae cultures are evaluated. [less ▲]

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See detailDiversity of Bacterial Communities in a Profile of a Winter Wheat Field: Known and Unknown Members
Stroobants, Aurore ULg; Degrune, Florine ULg; Olivier, Claire et al

in Microbial Ecology (2014)

In soils, bacteria are very abundant and diverse. They are involved in various agro-ecosystem processes such as the nitrogen cycle, organic matter degradation, and soil formation. Yet, little is known ... [more ▼]

In soils, bacteria are very abundant and diverse. They are involved in various agro-ecosystem processes such as the nitrogen cycle, organic matter degradation, and soil formation. Yet, little is known about the distribution and composition of bacterial communities through the soil profile, particularly in agricultural soils, as most studies have focused only on topsoils or forest and grassland soils. In the present work, we have used bar-coded pyrosequencing analysis of the V3 region of the 16S rRNA gene to analyze bacterial diversity in a profile (depths 10, 25, and 45 cm) of a well-characterized field of winter wheat. Taxonomic assignment was carried out with the Ribosomal Database Project (RDP) Classifier program with three bootstrap scores: a main run at 0.80, a confirmation run at 0.99, and a run at 0 to gain information on the unknown bacteria. Our results show that biomass and bacterial quantity and diversity decreased greatly with depth. Depth also had an impact, in terms of relative sequence abundance, on 81 % of the most represented taxonomic ranks, notably the ranks Proteobacteria, Bacteroidetes, Actinobacteridae, and Acidobacteria. Bacterial community composition differed more strongly between the topsoil (10 and 25 cm) and subsoil (45 cm) than between levels in the topsoil, mainly because of shifts in the carbon, nitrogen, and potassium contents. The subsoil also contained more unknown bacteria, 53.96 % on the average, than did the topsoil, with 42.06 % at 10 cm and 45.59 % at 25 cm. Most of these unknown bacteria seem to belong to Deltaproteobacteria, Actinobacteria, Rhizobiales, and Acidobacteria. [less ▲]

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See detail(Wrong) representations of physical activity, from definition to recommandations
Cloes, Marc ULg

Conference (2014, July 10)

Faisant partie intégrante de notre vie quotidienne, l’activité physique et la sédentarité constituent deux notions qui s’opposent dans la conception d’un style de vie sain. Les recherches actuelles ... [more ▼]

Faisant partie intégrante de notre vie quotidienne, l’activité physique et la sédentarité constituent deux notions qui s’opposent dans la conception d’un style de vie sain. Les recherches actuelles montrent que chacune d’elles devrait faire l’objet d’une attention particulière. Toutefois, qu’ils fassent partie du grand public ou appartiennent à des professions liées à la santé, il apparait que les individus ne construisent pas toujours des représentations adéquates à propos des bonnes habitudes de vie. Dans la perspective d’influencer favorablement la culture des citoyens en matière d’activité physique, il s’avère donc nécessaire de rappeler régulièrement les informations clés qui devraient être retenues et appliquées dans la vie de tous les jours. Afin d’illustrer la manière avec laquelle les représentations peuvent constituer le fil rouge d’un processus amenant les gens à adopter un style de vie physiquement actif et peu sédentaire, nous passerons brièvement en revue la définition de l’activité physique, l’identification de ses effets et les recommandations proposées actuellement par les agences de santé publique. Nous utiliserons différentes approches ludiques originales, susceptibles de faire vivre aux participants des expériences visant à stimuler le traitement des informations et à privilégier leur rétention. Au niveau de la définition de l’activité physique, l’objectif consistera à faire ressortir les différentes dimensions de l’activité physique. Puisque les recherches les plus récentes en soulignent l’incidence de plus en plus marquée, nous insisterons également sur la distinction entre les différents niveaux d’intensité de la pratique. Ensuite, une classification des effets bénéfiques de l’activité physique sera proposée avant une révision des recommandations internationales. Les modalités de présentation originales qui seront mises en place stimuleront la prise de conscience de certaines mauvaises représentations, courantes dans le public. La dernière partie de l’exposé consistera à illustrer les contre-arguments à opposer à ceux qui ne sont pas encore convaincus qu’ils pourraient bouger davantage. [less ▲]

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See detailSelf broadening coefficients and improved line intensities for the n7 band of C2H4 near 10.5 mm, and impact on ethylene retrievals from Jungfraujoch solar spectra
Vander Auwera, Jean; Fayt, André; Tudorie, Marcela et al

Poster (2014, July 10)

Ethylene (ethene, C2H4) is a tropospheric pollutant on the Earth, also present as a by-product of methane photochemistry in the atmosphere of outer solar system bodies. Remote sensing of ethylene in the ... [more ▼]

Ethylene (ethene, C2H4) is a tropospheric pollutant on the Earth, also present as a by-product of methane photochemistry in the atmosphere of outer solar system bodies. Remote sensing of ethylene in the infrared range relies on the 10 mm region. This spectral range corresponds to the excitation of 7 modes of vibration of 12C2H4, 4 of which being infrared active (see Fig. 1 of [1]). The corresponding n10, n7, n4 and n12 bands are located near 826, 949, 1026 and 1442 cm-1, respectively [1]. Among these, the n7 band is the strongest, indeed used for remote sensing measurements of ethylene. Relying on high-resolution Fourier transform infrared (FTIR) spectra recorded in Brussels, the present work involved extensive measurements of individual line intensities and self broadening coefficients for the n7 band of 12C2H4. Compared to the corresponding information available in the latest edition of the HITRAN spectroscopic database (HITRAN 2012 [2]), the measured line intensities were found to be higher by about 10 % for high J lines in the P branch and lower by about 5 % for high J lines of the R branch, varying between these two limits roughly linearly with the line positions. Test calculations performed in this work indicated that these discrepancies could result from the relative values of the transition moments of the n10, n7 and n12 bands used when the information provided in HITRAN was generated (the transition moment of the n4 band was set to zero). The measured self broadening coefficients exhibit a dependence on both J and Ka, which was modeled empirically. The spectroscopic information for ethylene available in HITRAN 2012 was modified to match the present observations. The impact of these modifications on retrievals of atmospheric ethylene was then evaluated via FTIR retrievals in the 949.0 – 952.0 cm-1 microwindow, from a subset of ground-based high-resolution FTIR solar spectra recorded at the Jungfraujoch station. The new line intensities were found to lead to a reduction of the measured total columns of ethylene by -4.1±0.1 %, compared to the use of HITRAN 2012. [less ▲]

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See detailOutils d’étude pour caractériser l’impact de l’ hydrodynamique sur la culture de cellules animales adhérentes cultivées sur microporteurs en bioréacteurs à cuve agitée
Collignon, Marie-Laure ULg

Conference (2014, July 10)

Cette présentation montre l'importance du choix des conditions d'agitation lors de la culture de cellules animales adhérentes sur microporteurs en bioréacteurs à cuve agitée. Elle montre des exemples d ... [more ▼]

Cette présentation montre l'importance du choix des conditions d'agitation lors de la culture de cellules animales adhérentes sur microporteurs en bioréacteurs à cuve agitée. Elle montre des exemples d'outils pour caractériser à l'échelle locale l'hydrodynamique au sein de ces bioréacteurs et une approche Euler-Lagrange qui a terme permettra de faire le lien entre l'hydrodynamique et la réponse cellulaire grâce à l'établissement de l'historique de conditions rencontrées localement par les cellules. [less ▲]

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See detailWhich links exist between depression, engagement in activities’ level and several psychological processes?
Wagener, Aurélie ULg; Blairy, Sylvie ULg

Poster (2014, July 09)

In Europe, depression affects 33.4 millions of people every year. According to the World Health Organization, depression will be the leading cause of disabilities in 2030. This highlights the need for ... [more ▼]

In Europe, depression affects 33.4 millions of people every year. According to the World Health Organization, depression will be the leading cause of disabilities in 2030. This highlights the need for available, effective and efficient treatments of this psychopathology. In order to offer such treatments, there is a need for a deep understanding of depression’s mechanisms. Depression is characterized by a decrease of the level of engagement in activities: for instance, depressed patients stay in bed, don’t see friends, don’t go out anymore and can be on sick leave for a long period of time. Reciprocally, this decrease maintains depressive symptoms. This link between depression and level of engagement in activities is well-established in the scientific literature. However, no study has, until yet, determined which psychological processes are mediators of this link. Therefore, this study’s aim is to determine these psychological processes. In order to reach this aim, 500 subjects, suffering from psychopathology or not, will fulfill a set of questionnaires. These questionnaires will assess mood (anxiety and depression), level of engagement in activities and five categories of psychological processes that have been selected from different theoretical models of depression (self-image, environmental satisfaction, negative repetitive thoughts, experiential avoidance and emotional regulation). Statistical analysis will be performed in order to confirm a LISREL model. Data collection is ongoing and results will be presented and discussed during the congress. [less ▲]

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