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See detailDensity functional theory beyond the linear regime: Validating an adiabatic local density approximation
Helbig, N.; Fuks, J. I.; Casula, M. et al

in Physical Review. A (2011), 83

We present a local density approximation (LDA) for one-dimensional (1D) systems interacting via the soft-Coulomb interaction based on quantum Monte Carlo calculations. Results for the ground-state ... [more ▼]

We present a local density approximation (LDA) for one-dimensional (1D) systems interacting via the soft-Coulomb interaction based on quantum Monte Carlo calculations. Results for the ground-state energies and ionization potentials of finite 1D systems show excellent agreement with exact calculations obtained by exploiting the mapping of an N-electron system in d dimensions onto a single electron in N×d dimensions, properly symmetrized by the Young diagrams. We conclude that 1D LDA is of the same quality as its three-dimensional (3D) counterpart, and we infer conclusions about 3D LDA. The linear and nonlinear time-dependent responses of 1D model systems using LDA, exact exchange, and the exact solution are investigated and show very good agreement in both cases, except for the well-known problem of missing double excitations. Consequently, the 3D LDA is expected to be of good quality beyond the linear response. In addition, the 1D LDA should prove useful in modeling the interaction of atoms with strong laser fields, where this specific 1D model is often used. [less ▲]

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See detailRelations entre la structure et la texture poreuse de xérogels de TiO2 dopés au phosphore et leurs propriétés photocatalytiques
Bodson, Céline ULg; Cattoën, Xavier; Bied, Catherine et al

in Récents Progrès en Génie des Procédés, Lavoisier Technique et Documentation, Volume 101, 6 p. (CD-ROM) (2011)

The sol-gel process is used to prepare phosphorus (P)-doped TiO2 xerogels by cogelation of Ti(O-iPr)4 with a functionalized P-based alkoxide : NH2-(CH2)2-NH-(CH2)2-P(O)-(OEt)2, in various alcohols. These ... [more ▼]

The sol-gel process is used to prepare phosphorus (P)-doped TiO2 xerogels by cogelation of Ti(O-iPr)4 with a functionalized P-based alkoxide : NH2-(CH2)2-NH-(CH2)2-P(O)-(OEt)2, in various alcohols. These xerogels were dried under vacuum at 150°C during 12 h, and calcined under air for 5 h at 350 °C, 450 °C, 550 °C and 650 °C. The samples obtained were characterized by X-ray diffraction, nitrogen adsorption-desorption isotherms and diffuse reflectance spectroscopy in UV/Vis region. The presence of phosphorus in the samples leads to a significant increase of their specific surface area, proportionally to the amount of phosphorus in the sample. Furthermore, the doping of the TiO2 by a phosphonate compound increases the thermal stability of the TiO2 and delays the phase transformation from amorphous to anatase. The diffuse reflectance measurements clearly show the translation of absorption peak of TiO2 towards the visible region when the content in phosphorus increases. Indeed, it is observed a degradation of the p-nitrophenol under visible light by using these P-doped TiO2 xerogels, which means that the P-doping enhances the photocatalytic activity in the visible region. [less ▲]

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See detailPauvreté et mortalité différentielle chez les personnes âgées
Lefebvre, Mathieu ULg; Pestieau, Pierre ULg; Ponthiere, Grégory ULg

in Reflets et Perspectives de la Vie Economique (2011), L(4), 45-54

Cette note a pour objectif d’illustrer, dans le cas de la Belgique et de ses régions, un problème particulier posé par la mesure de la pauvreté. Etant donné que la mortalité varie selon le niveau de ... [more ▼]

Cette note a pour objectif d’illustrer, dans le cas de la Belgique et de ses régions, un problème particulier posé par la mesure de la pauvreté. Etant donné que la mortalité varie selon le niveau de revenu – les personnes aux revenus plus élevés vivant plus longtemps, en moyenne, que les personnes aux revenus plus faibles – les taux de pauvreté calculés pour les classes âgées dépendent non seulement de ce que l’on pourrait appeler la vraie pauvreté, mais aussi de la sélection induite par la mortalité différentielle selon le revenu. En calculant les taux de pauvreté que l’on observerait si des personnes avec différents niveaux de revenus avaient toutes la même espérance de vie, on peut ainsi estimer la vraie pauvreté, en neutralisant les interférences dues à la mortalité différentielle. Cet ajustement des mesures de pauvreté est particulièrement intéressant pour la Belgique, où les écarts de longévité entre Flamands et Francophones et entre riches et moins riches sont importants. [less ▲]

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See detailPresent day carbon dioxide fluxes in the coastal ocean and possible feedbacks under global change
Borges, Alberto ULg

in da Silva Duarte, P. M.; Santana Casiano, J. M. (Eds.) Oceans and the atmospheric carbon content (2011)

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See detailMathematical modeling of cell-cell and cell-matrix adhesion in tissue engineering using continuum models
Geris, Liesbet ULg; Gerisch, A.

in Geffen, A. (Ed.) Cellular and Biomolecular Mechanics and Mechanobiology (2011)

Key factors in the formation of cell aggregates in tissue engineering and other fields are the cell-cell and cell-matrix interactions. Other important factors are culture conditions such as nutrient and ... [more ▼]

Key factors in the formation of cell aggregates in tissue engineering and other fields are the cell-cell and cell-matrix interactions. Other important factors are culture conditions such as nutrient and oxygen supply and the characteristics of the environment (medium versus hydrogel). As mathematical models are increasingly used to investigate biological phenomena, it is important that processes such as cell adhesion are adequately described in the models. Recently a technique was developed to incorporate cell-cell and cell-matrix adhesion in continuum models through the use of non-local terms. In this study we apply this technique to model adhesion in a cell-in-gel culture set-up often found in tissue engineering applications. We briefly describe the biological issues underlying this study and the various modeling techniques used to capture adhesive behaviour. We furthermore elaborate on the numerical techniques that were developed in the course of this study. Finally, we consider a tissue engineering model that describes the spatiotemporal evolution of the concentration of cells, matrix, hydrogel, matrix degrading enzymes and oxygen/nutrients in a cell-in-gel culture system. Sensitivity analyses indicate a clear influence of the different adhesive processes on the final cell and collagen density and distribution, demonstrating the significance of cell adhesion in tissue engineering and the potential of the proposed mathematical technique. [less ▲]

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See detailIdentification of differential item functioning in multiple-group settings: A multivariate outlier detection approach
Magis, David ULg; De Boeck, Paul

in Multivariate Behavioral Research (2011), 46

This paper focuses on the identification of differential item functioning (DIF) when more than two groups of examinees are considered. We propose to consider items as elements of a multivariate space ... [more ▼]

This paper focuses on the identification of differential item functioning (DIF) when more than two groups of examinees are considered. We propose to consider items as elements of a multivariate space, where DIF items are outlying elements. Following this approach, the situation of multiple groups is a quite natural case. A robust statistics technique is proposed to identify DIF items as outliers in the multivariate space. For low dimensionalities, up to two three groups, also a simple graphical tool is derived. We illustrate our approach with a re-analysis of data from Kim, Cohen, and Park (1995) on using calculators for a mathematics test. [less ▲]

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See detailInventaire des archives de la Société anonyme d'Ougrée-Marihaye (1835-1955)
Delvaux, Anne-Catherine ULg

Book published by Archives générales du Royaume (2011)

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See detailTolerability of shortened infliximab infusion times in patients with inflammatory bowel disease: a single center cohort study
Breynaert, C; Ferrante, F; Fidder, H et al

in Acta Gastro-Enterologica Belgica (2011)

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See detailComplément d'épidémiologie
Bruyère, Olivier ULg

Learning material (2011)

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See detailOriginal findings associated with two cases of bovine papular stomatitis
Dal Pozzo, Fabiana ULg; Martinelle, Ludovic ULg; Gallina, L. et al

in Journal of Clinical Microbiology (2011), 49(12), 4397-4400

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See detailSubtrochanteric fractures after long-term treatment with bisphosphonates: a European Society on Clinical and Economic Aspects of Osteoporosis and Osteoarthritis, and International Osteoporosis Foundation Working Group Report.
Rizzoli, R.; Akesson, K.; Bouxsein, M. et al

in Osteoporosis International (2011), 22

This paper reviews the evidence for an association between atypical subtrochanteric fractures and long-term bisphosphonate use. Clinical case reports/reviews and case-control studies report this ... [more ▼]

This paper reviews the evidence for an association between atypical subtrochanteric fractures and long-term bisphosphonate use. Clinical case reports/reviews and case-control studies report this association, but retrospective phase III trial analyses show no increased risk. Bisphosphonate use may be associated with atypical subtrochanteric fractures, but the case is yet unproven. INTRODUCTION: A Working Group of the European Society on Clinical and Economic Aspects of Osteoporosis and Osteoarthritis and the International Osteoporosis Foundation has reviewed the evidence for a causal association between subtrochanteric fractures and long-term treatment with bisphosphonates, with the aim of identifying areas for further research and providing recommendations for physicians. METHODS: A PubMed search of literature from 1994 to May 2010 was performed using key search terms, and articles pertinent to subtrochanteric fractures following bisphosphonate use were analysed. RESULTS: Several clinical case reports and case reviews report a possible association between atypical fractures at the subtrochanteric region of the femur in bisphosphonate-treated patients. Common features of these 'atypical' fractures include prodromal pain, occurrence with minimal/no trauma, a thickened diaphyseal cortex and transverse fracture pattern. Some small case-control studies report the same association, but a large register-based study and retrospective analyses of phase III trials of bisphosphonates do not show an increased risk of subtrochanteric fractures with bisphosphonate use. The number of atypical subtrochanteric fractures in association with bisphosphonates is an estimated one per 1,000 per year. It is recommended that physicians remain vigilant in assessing their patients treated with bisphosphonates for the treatment or prevention of osteoporosis and advise patients of the potential risks. CONCLUSIONS: Bisphosphonate use may be associated with atypical subtrochanteric fractures, but the case is unproven and requires further research. Were the case to be proven, the risk-benefit ratio still remains favourable for use of bisphosphonates to prevent fractures. [less ▲]

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See detailOptimization of multibody systems and their structural components
Bruls, Olivier ULg; Lemaire, Etienne ULg; Duysinx, Pierre ULg et al

in Blajer, W.; Arczewski, K.; Fraczek, J. (Eds.) et al Multibody Dynamics: Computational Methods and Applications (2011)

This work addresses the optimization of flexible multibody systems based on the dynamic response of the full system with large amplitude motions and elastic deflections. The simulation model involves a ... [more ▼]

This work addresses the optimization of flexible multibody systems based on the dynamic response of the full system with large amplitude motions and elastic deflections. The simulation model involves a nonlinear finite element formulation, a time integration scheme and a sensitivity analysis and it can be efficiently exploited in an optimization loop. In particular, the paper focuses on the topology optimization of structural components embedded in multibody systems. Generally, topology optimization techniques consider that the structural component is isolated from the rest of the mechanism and use simplified quasi-static load cases to mimic the complex loadings in service. In contrast, we show that an optimization directly based on the dynamic response of the flexible multibody system leads to a more integrated approach. The method is applied to truss structural components. Each truss is represented by a separate structural universe of beams with a topology design variable attached to each one. A SIMP model (or a variant of the power law) is used to penalize intermediate densities. The optimization formulation is stated as the minimization of the mean compliance over a time period or as the minimization of the mean tip deflection during a given trajectory, subject to a volume constraint. In order to illustrate the benefits of the integrated design approach, the case of a two degrees-of-freedom robot arm is developed. [less ▲]

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See detailModélisation numérique de l'expérience SDZ pour l'Andra
Pardoen, Benoît ULg; Charlier, Robert ULg; Radu, Jean-Pol ULg

Report (2011)

An in situ ventilation test (SDZ) is performed by the French national radioactive waste management agency (ANDRA) in the Meuse/Haute-Marne underground research laboratory. The aim is to characterise the ... [more ▼]

An in situ ventilation test (SDZ) is performed by the French national radioactive waste management agency (ANDRA) in the Meuse/Haute-Marne underground research laboratory. The aim is to characterise the effect of the desaturation and possible resaturation of the damaged zone located around an experimental gallery due to controlled ventilation imposed in this gallery. Hydro and hydro-mechanical numerical modellings are realised in order to acquire a better understanding of clayey rock behaviour and transfers occurring during the test. [less ▲]

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See detailBenthic remineralization in the northwest European continental margin (northern Bay of Biscay)
Suykens, Kim; Schmidt, Sabine; Delille, Bruno ULg et al

in Continental Shelf Research (2011), 31

We report a dataset of sediment characteristics and biogeochemical fluxes at the watersediment interface at the northwest European continental margin (northern Bay of Biscay). Cores were obtained in June ... [more ▼]

We report a dataset of sediment characteristics and biogeochemical fluxes at the watersediment interface at the northwest European continental margin (northern Bay of Biscay). Cores were obtained in June 2006, May 2007 and 2008, at 18 stations on the shelf break (120 to 180 m), and at 2 stations on the continental slope (520 m and 680 m). Water-sediment fluxes of dissolved oxygen (O2), total alkalinity (TA), nitrate (NO3-), and dissolved silicate (DSi) were measured at a total of 20 stations. Sediment characteristics include: grain size, chlorophyll-a (Chl-a) and phaeopigment (Phaeo) content, particulate organic (POC) and inorganic (PIC) carbon content, and lead-210 (210Pb) and thorium-234 (234Th) activities. Sediments were sandy (fine to coarse) with organic matter (OM) (1.0 - 4.0 %) and Chl-a (0.01 - 0.95 μg g-1) contents comparable to previous investigations in the same region, and a relatively high PIC fraction (0.8 - 10.2 %). Water-sediment O2 fluxes (-2.4 to -8.4 mmol O2 m-2 d-1) were low compared to other coastal environments and correlated well with OM and Chl-a content. 234Th activity profiles indicated that Chl-a sediment content was mainly controlled by physical mixing processes related to local hydrodynamics. The correlation between water-sediment fluxes of O2 and NO3- indicated a close coupling of nitrification/denitrification and total benthic organic carbon degradation. Dissolution of biogenic silica (0.05 to 0.95 mmol m-2 d-1) seemed uncoupled from organic carbon degradation, as characterized by water-sediment O2 fluxes. The link between water-sediment fluxes of TA and O2 indicated the occurrence of metabolic driven dissolution of calcium carbonates (CaCO3) in the sediments (~ 0.33 ± 0.47 mmol m-2 d-1) which represented ~ 1 % of the pelagic calcification rates due to coccolithophores measured during the cruises. These CaCO3 dissolution rates were below those reported in sediments of continental slopes and of the deep ocean, probably due to the high over-saturation with respect to CaCO3 of the water column overlying the continental shelf sediments of the northern Bay of Biscay. Rates of total benthic organic carbon degradation were low compared to water column rates of primary production and aphotic community respiration obtained during the cruises. [less ▲]

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See detailRate of Malignancies and Infections in a Large Single Center Cohort of IBD Patients Treated With Thiopurines and Anti-TNF-Antibodies.
Ochsenkühn, T; Steinborn, A; Beigel, F et al

in Journal of Crohn’s and Colitis (2011)

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See detailIntroduction sur la croissance
Kaux, Jean-François ULg

Learning material (2011)

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See detailEffective Production of the Biodiesel Additive STBE by a Continuous Flow Process
Monbaliu, Jean-Christophe ULg; Winter, Marc; Chevalier, Bérengère et al

in Bioresource Technology (2011), 102

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See detailInventaire des archives de la Compagnie générale des Conduites d'Eau (1865-1965)
Delvaux, Anne-Catherine ULg

Book published by Archives générales du Royaume (2011)

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