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See detailLes éventrations parastomales: prévention et traitement
DETRY, Olivier ULg

Scientific conference (2017, February 24)

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See detailInterplay between Penicillin-binding proteins and SEDS proteins promotes bacterial cell wall synthesis.
Leclercq, Sophie ULg; Derouaux, Adeline ULg; Olatunji, Samir ULg et al

in Scientific Reports (2017), 7

Bacteria utilize specialized multi-protein machineries to synthesize the essential peptidoglycan (PG) cell wall during growth and division. The divisome controls septal PG synthesis and separation of ... [more ▼]

Bacteria utilize specialized multi-protein machineries to synthesize the essential peptidoglycan (PG) cell wall during growth and division. The divisome controls septal PG synthesis and separation of daughter cells. In E. coli, the lipid II transporter candidate FtsW is thought to work in concert with the PG synthases penicillin-binding proteins PBP3 and PBP1b. Yet, the exact molecular mechanisms of their function in complexes are largely unknown. We show that FtsW interacts with PBP1b and lipid II and that PBP1b, FtsW and PBP3 co-purify suggesting that they form a trimeric complex. We also show that the large loop between transmembrane helices 7 and 8 of FtsW is important for the interaction with PBP3. Moreover, we found that FtsW, but not the other flippase candidate MurJ, impairs lipid II polymerization and peptide cross-linking activities of PBP1b, and that PBP3 relieves these inhibitory effects. All together the results suggest that FtsW interacts with lipid II preventing its polymerization by PBP1b unless PBP3 is also present, indicating that PBP3 facilitates lipid II release and/or its transfer to PBP1b after transport across the cytoplasmic membrane. This tight regulatory mechanism is consistent with the cell's need to ensure appropriate use of the limited pool of lipid II. [less ▲]

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See detailA class of valid inequalities for multilinear 0-1 optimization problems
Crama, Yves ULg; Rodriguez Heck, Elisabeth ULg

in Discrete Optimization (2017)

This paper investigates the polytope associated with the classical standard linearization technique for the unconstrained optimization of multilinear polynomials in 0-1 variables. A new class of valid ... [more ▼]

This paper investigates the polytope associated with the classical standard linearization technique for the unconstrained optimization of multilinear polynomials in 0-1 variables. A new class of valid inequalities, called 2-links, is introduced to strengthen the LP relaxation of the standard linearization. The addition of the 2-links to the standard linearization inequalities provides a complete description of the convex hull of integer solutions for the case of functions consisting of at most two nonlinear monomials. For the general case, various computational experiments show that the 2- links improve both the standard linearization bound and the computational performance of exact branch & cut methods. The improvements are especially significant for a class of instances inspired from the image restoration problem in computer vision. The magnitude of this effect is rather surprising in that the 2-links are in relatively small number (quadratic in the number of terms of the objective function). [less ▲]

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See detailDialogues sur la Diversité
Brahy, Rachel ULg; Dumont, Elisabeth

Conference given outside the academic context (2017)

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See detailImplementation of the biogenic emission model MEGAN(v2.1) into the ECHAM6-HAMMOZ chemistry climate model
Henrot, Alexandra-Jane ULg; Stanelle, T.; Schröder, S. et al

in Geoscientific Model Development [=GMD] (2017), 10

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See detailSeven temperate terrestrial planets around the nearby ultracool dwarf star
Gillon, Michaël ULg; Triaud, Amaury; Demory, Brice-Olivier et al

in Nature (2017), 542

One focus of modern astronomy is to detect temperate terrestrial exoplanets well-suited for atmospheric characterisation. A milestone was recently achieved with the detection of three Earth-sized planets ... [more ▼]

One focus of modern astronomy is to detect temperate terrestrial exoplanets well-suited for atmospheric characterisation. A milestone was recently achieved with the detection of three Earth-sized planets transiting (i.e. passing in front of) a star just 8% the mass of the Sun 12 parsecs away. Indeed, the transiting configuration of these planets combined with the Jupiter-like size of their host star - named TRAPPIST-1 - makes possible indepth studies of their atmospheric properties with current and future astronomical facilities. Here we report the results of an intensive photometric monitoring campaign of that star from the ground and with the Spitzer Space Telescope. Our observations reveal that at least seven planets with sizes and masses similar to the Earth revolve around TRAPPIST-1. The six inner planets form a near-resonant chain such that their orbital periods (1.51, 2.42, 4.04, 6.06, 9.21, 12.35 days) are near ratios of small integers. This architecture suggests that the planets formed farther from the star and migrated inward. The seven planets have equilibrium temperatures low enough to make possible liquid water on their surfaces. [less ▲]

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See detailL’imprimerie à Bruxelles sous les archiducs Albert et Isabelle (1598-1633)
Adam, Renaud ULg

Conference (2017, February 23)

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See detailL’impôt des sociétés dans une perspective internationale : entre concurrence et convergence
Richelle, Isabelle ULg

Scientific conference (2017, February 23)

Réformer l’imposition des sociétés implique de tenir compte de sa place dans le système fiscal. L’on songe à l’articulation avec l’impôt des personnes physiques, auquel sont soumis les entreprises ... [more ▼]

Réformer l’imposition des sociétés implique de tenir compte de sa place dans le système fiscal. L’on songe à l’articulation avec l’impôt des personnes physiques, auquel sont soumis les entreprises personnelles et les actionnaires individuels. Par ailleurs, est également abordée la question de l’efficacité des incitants fiscaux à l’Isoc, notamment en matière d’investissement, de recherche ou d’environnement. - Les mutations du cadre fiscal international réduisent fortement la marge de manœuvre du législateur belge. Les initiatives de l’OCDE (BEPS) et de l’Union européenne obligent la Belgique à repenser sa politique dite « de niches fiscales » et pourraient déboucher vers une plus forte convergence des systèmes fiscaux. En parallèle, il faut tenir compte des réformes mises en œuvre dans les autres Etats européens, qui eux aussi cherchent à s’adapter au nouveau contexte tout en restant compétitifs [less ▲]

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See detailEmbarquement pour Mars: défi et opportunité
Stiepen, Arnaud ULg

Conference given outside the academic context (2017)

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See detailComment le changement climatique influence-t-il la croissance du hêtre (Fagus sylvatica L.) le long du gradient bioclimatique de la Belgique ? Une approche dendroécologique.
Latte, Nicolas ULg

Doctoral thesis (2017)

Health anomalies (e.g., worsening crown conditions) on beech (Fagus sylvatica L.) observed throughout Europe since the 1990s have raised growing concerns among foresters, particularly about the future ... [more ▼]

Health anomalies (e.g., worsening crown conditions) on beech (Fagus sylvatica L.) observed throughout Europe since the 1990s have raised growing concerns among foresters, particularly about the future behavior of the species in the face of climate change. This PhD research examined the relationship between beech and its environment in the context of global changes using dendroecology, combination of dendrochronology and forest ecology. The radial growth was used to evaluate the effects of global changes, particularly climate change, on beech development and vitality over time along a bioclimatic gradient in Belgium. Various analyses were carried out using dendrochronological tools (pointer years, mean sensitivity, growth-climate correlation, etc.) and modeling approaches (linear and non-linear mixed models, partial least squares regression, etc.) considering several scales: tree, stand and region. Results show that climate predominantly influenced beech growth since the mid-20th century and did so rather uniformly across Belgium. Beech mean sensitivity increased mainly in response to the higher frequency and intensity of summer heat waves and spring droughts. Isolated but pronounced annual growth reductions induced a gradual diminution of mean growth. The increasing influence of climate progressively concealed the effect of local site growing conditions inducing strong between-sites synchronization along the bioclimatic gradient. Increasing mean sensitivity and decreasing mean growth were more pronounced in lowlands than in uplands, and for a given site, older trees are more affected than younger ones. Although mean sensitivity increases and mean growth decreases naturally with age, the climate change effect was much more important than the age effect. Furthermore, within a tree, along the main stem, climate sensitivity slightly decreased from breast height to crown base and strongly increased from crown base to tree top. These results were interpreted based on ecophysiological knowledge of beech. The influences of silviculture, soil compaction and nitrogen deposition (as part of atmospheric pollution) as well as the consequences of the past and future climate change on beech were discussed. Comparisons with other studies in Europe highlighted that beech is affected on a large part of its natural distribution range (except in high altitude and high latitude). Contrary to what one might think, beech is not only affected in the southern limit (Mediterranean). Although growing conditions are more favorable in Belgium, beech has also more to lose. Beech has coped with global change up to now. Although its climate sensitivity increased and its mean growth decreased, diebacks observed these last years in Belgium were scarce and generally scattered. However, considering the upcoming climate change, the phytosanitary risk will undeniable increased. Forest policy should now integrate that risk and prepare managers to anticipate and prevent it. [less ▲]

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See detailJeu vidéo : réception et discours
Delbouille, Julie ULg

Scientific conference (2017, February 23)

De nombreuses étiquettes sont associées par la presse et par le grand public tant au jeu vidéo qu’à ses utilisateurs. En se penchant sur les « discours à propos du jeu vidéo », cette séance de cours vise ... [more ▼]

De nombreuses étiquettes sont associées par la presse et par le grand public tant au jeu vidéo qu’à ses utilisateurs. En se penchant sur les « discours à propos du jeu vidéo », cette séance de cours vise à déconstruire les clichés habituellement associés au médium : en étudiant tant les pratiques vidéoludiques que l’évolution des discours, elle tente de reconstruire la place réelle occupée par le jeu vidéo au sein des foyers dans le monde francophone. [less ▲]

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See detailDrivers and patterns of diversification in reef fishes
Frederich, Bruno ULg

Scientific conference (2017, February 23)

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See detailTroubles de la Régulation du Traitement sensoriel
SCHOLL, Jean-Marc ULg

Conference given outside the academic context (2017)

Actuellement, peu de médecins et de psychologues connaissent les « Troubles de la Régulation Sensorielle ». Or, chez le petit enfant, ils peuvent fortement influencer sa psychologie, ses comportements et ... [more ▼]

Actuellement, peu de médecins et de psychologues connaissent les « Troubles de la Régulation Sensorielle ». Or, chez le petit enfant, ils peuvent fortement influencer sa psychologie, ses comportements et altérer son fonctionnement. Ces difficultés peuvent demeurer chez l’adulte et interférer sur son fonctionnement quotidien. Ainsi, il est utile de former le réseau des professionnels, particulièrement le réseau de la santé mentale de l’enfance et le réseau des crèches et de l’enseignement maternel. Le diagnostic d'un Trouble de la Régulation du traitement Sensoriel est réalisé à partir de l'anamnèse et de la description de l'enfant dans ses différents milieux de vie. Afin de réaliser un dépistage, cette présentation donne une sémiologie précise permettant de reconnaître les signes et symptômes chez l'enfant et chez l'adulte. Il est également utile de systématiquement rechercher s'il n'y a pas d'autres difficultés et comorbidités s'ajoutant à ce premier diagnostic. Le module de formation ici présenté donne divers points de repères : I. Données générales : 1) Prévalence 2) Enjeu de santé publique 3) Vignette Clément 4) Vignette Aude 5) Voies d’entrée des stimuli sensoriels 6) Traitement central de l’information 7) Régulation sensorielle 8) Altération du développement de l’enfant II. Du dépistage au diagnostic : 1) Dépistage et diagnostic 2) Dépistage : hyper- /hypo-sensibilités 3) Dépistage : Exemples d’hypersensibilités 4) Dépistage : Exemples d’hyposensibilités [less ▲]

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See detailMulti-period vehicle allocation with uncertain transportation requests
Crama, Yves ULg; Pironet, Thierry ULg

E-print/Working paper (2017)

This work investigates optimization techniques for a multi-period vehicle allocation problem with uncertain requests. A company owning a limited fleet of trucks attempts to maximize its operational profit ... [more ▼]

This work investigates optimization techniques for a multi-period vehicle allocation problem with uncertain requests. A company owning a limited fleet of trucks attempts to maximize its operational profit over an infinite horizon by optimally assigning transportation orders to the vehicles. Its profit stems from profits collected when transporting full truckloads, minus costs incurred when waiting or when moving unladen. The stochastic component of the problem arises from the uncertainty on the realization of each transportation order. The methodology is based on optimizing decisions for deterministic scenarios. Several policies are generated in this way, either by simple heuristics, or by more complex approaches, such as consensus and restricted expectation algorithms, or from network flow formulations over subtrees of scenarios. Myopic and a-posteriori deterministic optimization models are used to compute bounds allowing for performance evaluation. Numerical experiments are performed on various instances featuring different numbers of orders, graph sizes, sparsity, and probability distributions, and the performance of the algorithms is assessed by statistical tests. The robustness of various policies with respect to erroneous evaluations of the probability distributions is also analyzed. [less ▲]

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See detailCluster growth in driven granular gases
Noirhomme, Martial ULg; Ludewig, François; Vandewalle, Nicolas ULg et al

in Physical Review. E : Statistical, Nonlinear, and Soft Matter Physics (2017)

We investigate numerically and theoretically the internal structures of a driven granular gas in cuboidal cell geometries. Clustering is reported and particles are classified as gaseous or clustered via a ... [more ▼]

We investigate numerically and theoretically the internal structures of a driven granular gas in cuboidal cell geometries. Clustering is reported and particles are classified as gaseous or clustered via a local packing fraction criterion based on a Voronoi tessellation. We observe that small clusters arise in the corners of the box, elucidating early reports of partial clustering. These aggregates have a condensation-like surface growth. When a critical size is reached, a structural transition occurs and all clusters merge together, leaving a hole in the center of the cell. This hole then becomes the new center of particle capture. Taking into account all structural modifications and defining a saturation packing fraction, we propose an empirical model for the cluster growth. [less ▲]

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See detailFanfictions, blogs, web-poetry et jeux vidéo
Dupont, Bruno ULg; Barnabé, Fanny ULg

Scientific conference (2017, February 23)

Comment s'élaborent les cultures des fans ? Quels rapports se créent entre auteur et lecteur-créateur ? Quels sont les enjeux de ces cultures participatives et pourquoi est-il intéressant de les étudier ... [more ▼]

Comment s'élaborent les cultures des fans ? Quels rapports se créent entre auteur et lecteur-créateur ? Quels sont les enjeux de ces cultures participatives et pourquoi est-il intéressant de les étudier aujourd'hui ? [less ▲]

Detailed reference viewed: 54 (4 ULg)