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See detailSpin texture induced by oxygen vacancies in strontium perovskite (001) surfaces: A theoretical comparison between SrTiO3 and SrHfO3
Garcia Castro, Andrés Camilo ULg; Vergniory, Maia G.; Bousquet, Eric ULg et al

in Physical Review B (2016), 93

The electronic structure of SrTiO3 and SrHfO3 (001) surfaces with oxygen vacancies is studied by means of first-principles calculations. We reveal how oxygen vacancies within the first atomic layer of the ... [more ▼]

The electronic structure of SrTiO3 and SrHfO3 (001) surfaces with oxygen vacancies is studied by means of first-principles calculations. We reveal how oxygen vacancies within the first atomic layer of the SrTiO3 surface (i) induce a large antiferrodistortive motion of the oxygen octahedra at the surface, (ii) drive localized magnetic moments on the Ti 3d orbitals close to the vacancies, and (iii) form a two-dimensional electron gas localized within the first layers. The analysis of the spin texture of this system exhibits a splitting of the energy bands according to the Zeeman interaction, lowering of the Ti 3dxy level in comparison with dxz and dyz, and also an in-plane precession of the spins. No Rashba-like splitting for the ground state or for the ab initio molecular dynamics trajectory at 400 K is recognized as suggested recently by A. F. Santander-Syro et al. [Nat. Mater. 13, 1085 (2014)]. Instead, a sizable Rashba-like splitting is observed when the Ti atom is replaced by a heavier Hf atom with a much larger spin-orbit interaction. However, we observe the disappearance of the magnetism and the surface two-dimensional electron gas when full structural optimization of the SrHfO3 surface is performed. Our results uncover the sensitive interplay of spin-orbit coupling, atomic relaxations, and magnetism when tuning these Sr-based perovskites. [less ▲]

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See detailFar beyond primary poly(vinylamine)s through free radical copolymerization and amide hydrolysis
Dréan, Mathilde ULg; Guégan, Philippe; Jérôme, Christine ULg et al

in Polymer Chemistry (2016), 7(1), 69-78

Due to their affinity for many supports, their pH responsiveness, metal binding capacity and polyelectro- lyte complexation, poly(vinylamine) derivatives have attracted attention for many applications ... [more ▼]

Due to their affinity for many supports, their pH responsiveness, metal binding capacity and polyelectro- lyte complexation, poly(vinylamine) derivatives have attracted attention for many applications including coatings, water purification, or gas membrane separation. Nevertheless, most of them possess only pendant primary amines despite the possible benefits of incorporating different amino groups along the chain. In this work, a straightforward and scalable synthesis route towards polymers bearing primary and secondary amines, as well as imidazole groups, is reported. The general strategy relies on the radical copolymerization of different vinylamides and vinyl imidazoles followed by the hydrolysis of the resulting poly(vinylamide) derivatives. Binary and ternary free radical copolymerizations of N-vinylacetamide (NVA), N-methyl vinylacetamide (NMVA) and 1-vinylimidazole (VIm) were investigated and the reactivity ratios for each copolymerization system were determined. Thanks to these values a series of statistical copolymers with predictable composition and low deviation over the chain distribution could then be synthesized. Finally, the acidic hydrolysis of the acetamide functions towards the corresponding amine was performed and optimized. Copolymers containing various pendant amino groups and with low dispersity in the chain composition could be obtained, which opens new perspectives for the above mentioned applications. [less ▲]

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See detailVers un financement de la culture à deux vitesses?
Vandenbulke, Antoine ULg

Article for general public (2016)

The extension of the tax shelter to performing arts in Belgium: towards an increased privatization of culture funding?

Detailed reference viewed: 113 (8 ULg)
See detailCentre de réadaptation ambulatoire et réseau de soins infanto-juvéniles : De quelle multi-disciplinarité parle-t-on?
Garcet, Serge ULg

Conference given outside the academic context (2016)

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See detailBien soigner l'arthrose: un enjeu capital pour notre société!
Henrotin, Yves ULg

Conference (2016, January 07)

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See detailIndo-Trinidadian Women and the Indian Public Sphere: Women under the Influence?
Munos, Delphine ULg

Conference (2016, January 06)

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See detailExtramuros - État de la recherche et réflexion sur l’implémentation de l’ErE dans la formation initiale élargie à 5 ans des enseignants du primaire
Partoune, Christine ULg

Conference given outside the academic context (2016)

Propositions de réforme de la formation initiale pour que les enseignants du primaire exploitent davantage les environs immédiats de l'école pour développer l'éducation relative à l'environnement et ... [more ▼]

Propositions de réforme de la formation initiale pour que les enseignants du primaire exploitent davantage les environs immédiats de l'école pour développer l'éducation relative à l'environnement et fonder des apprentissages dans toutes les disciplines. [less ▲]

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See detailLe Risorgimento, la Belgique et l’Europe (1848-1870)
Genin, Vincent ULg

Conference given outside the academic context (2016)

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See detailA prospective cohort study of the clinical presentation of non-traumatic osteonecrosis of the femoral head: spine and knee symptoms as clinical presentation of hip osteonecrosis.
HAUZEUR, Jean-Philippe ULg; Malaise, Michel ULg; de MARTELAER, v

in International Orthopaedics (2016)

To study the clinical presentation of femoral head osteonecrosis (ONFH). Publications dedicated to this aspect of ONFH are rare. Our aim was to systematically collect and describe the clinical data.

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See detailFertility progression in Germany: An analysis using flexible nonparametric cure survival models
Bremhorst, Vincent; Kreyenfeld, Michaela; Lambert, Philippe ULg

E-print/Working paper (2016)

- Objective - This paper uses data from the German Socio-Economic Panel (GSOEP) to study the transition to second and third births. In particular, we seek to distinguish the factors that determine the ... [more ▼]

- Objective - This paper uses data from the German Socio-Economic Panel (GSOEP) to study the transition to second and third births. In particular, we seek to distinguish the factors that determine the timing of fertility from the factors that influence ultimate parity progression. - Methods - As a method, we employ cure survival models, a technique that is commonly used in epidemiological studies and in the statistical literature, but is only rarely applied to fertility research. - Results - We find that education has a different impact on the timing and the ultimate probability of having a second and a third birth. Furthermore, we show that the shape of the fertility schedule for the total population differs from that of “susceptible women” (i.e., those who have a second or a third child). - Conclusion - Standard event history models conflate timing and quantum effects. Our approach overcomes this shortcoming. It estimates separate parameters for the hazard rate of having a next child for the “susceptible population,” and the ultimate probability of having another child for the entire population at risk. - Contribution - We go beyond standard cure survival models (also known as split population models) used in fertility research by specifying a flexible non-parametric model (using Bayesian P-splines) for the latent distribution (related to the timing of an extra birth), instead of a parametric model. Our approach is (so far) limited to time-constant covariates, but can be extended to include time-varying covariates as well. [less ▲]

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See detailCLIMATE CHANGE : Causes and consequences (2016). "Global Societal Challenges and Smart Cities"
Ozer, Pierre ULg

Scientific conference (2016, January 05)

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See detailProcessing of a new class of multifunctional hybrid for electromagnetic absorption based on a foam filled honeycomb
Bollen, Pierre; Quievy, Nicolas; Detrembleur, Christophe ULg et al

in Materials & Design (2016), 89

A multifunctional hybrid material class in the form of a sandwich panel has been developed towards the com- bined optimization of mechanical and electromagnetic absorption performance. The faces of the ... [more ▼]

A multifunctional hybrid material class in the form of a sandwich panel has been developed towards the com- bined optimization of mechanical and electromagnetic absorption performance. The faces of the panel are made of glass fibre reinforced epoxy composites and the core is made of carbon nanotube reinforced polymer foam filling a metallic honeycomb. The different processing strategies and options tested to fabricate the core material are described aswell as the associated scientific and technological issues. The most efficient processing route is by foaming the nanocomposite with a chemical foaming agent directly inside the honeycomb. This route offers a good surface finish and the operation can be achieved in one step. But, in order to produce large panels with a semi-continuous process, thermo-mechanical insertion of the foamed nanocomposite with supercritical CO2 can be more suitable. The characterization of the electromagnetic absorption of the panels produced by dif- ferent routes shows that the performance is not much sensitive to processing defects making possible upscaling to mass production. [less ▲]

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See detailPour une histoire du jeu vidéo
Dozo, Björn-Olav ULg

Scientific conference (2016, January 04)

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See detailComprehensive comparison of the chemical and structural characterization of landfill leachate and leonardite humic fractions
Tahiri, Abdelghani ULg; Richel, Aurore ULg; Destain, Jacqueline ULg et al

in Analytical and Bioanalytical Chemistry (2016), 408(7), 1917-1928

Humic substances (HS) are complex and heterogeneous mixtures of organic compounds that occur everywhere in the environment. They represent most of the dissolved organic matter in soils, sediments (fossil ... [more ▼]

Humic substances (HS) are complex and heterogeneous mixtures of organic compounds that occur everywhere in the environment. They represent most of the dissolved organic matter in soils, sediments (fossil), water, and landfills. The exact structure of HS macromolecules has not yet been determined because of their complexity and heterogeneity. Various descriptions of HS are used depending on specific environments of origin and research interests. In order to improve the understanding of the structure of HS extracted from landfill leachate (LHS) and commercial HS from leonardite (HHS), this study sought to compare the composition and characterization of the structure of LHS and HHS using elemental composition, chromatographic (high-performance liquid chromatography (HPLC)), and spectroscopic techniques (UV–vis, FTIR, NMR, and MALDI-TOF). The results showed that LHS molecules have a lower molecular weight and less aromatic structure than HHS molecules. The characteristics of functional groups of both LHS and HHS, however, were basically similar, but there was some differences in absorbance intensity. There were also less aliphatic and acidic functional groups and more aromatic and polyphenolic compounds in the humic acid (HA) fraction than in the fulvic acid (FA) and other molecules (OM) fractions of both origins. The differences between LHS and HHS might be due to the time course of humification. Combining the results obtained from these analytical techniques cold improve our understanding of the structure of HS of different origins and thus enhance their potential use. [less ▲]

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See detailDer belgische Verfassungsgerichtshof
Behrendt, Christian ULg

in von Bogdandy, Armin; Grabenwarter, Christoph; Huber, Peter M. (Eds.) Ius Publicum Europaeum - Band VI - Verfassungsgerichtsbarkeit in Europa : Institutionen (2016)

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See detailAmplitude and frequency variations of oscillation modes in the pulsating DB white dwarf star KIC~08626021. The likely signature of nonlinear resonant mode coupling
Zong, W.; Charpinet, S.; Vauclair, G. et al

in Astronomy and Astrophysics (2016), 585

Context. The signatures of nonlinear effects affecting stellar oscillations are difficult to observe from ground observatories because of the lack of continuous high-precision photometric data spanning ... [more ▼]

Context. The signatures of nonlinear effects affecting stellar oscillations are difficult to observe from ground observatories because of the lack of continuous high-precision photometric data spanning extended enough time baselines. The unprecedented photometric quality and coverage provided by the Kepler spacecraft offers new opportunities to search for these phenomena. Aims: We use the Kepler data accumulated on the pulsating DB white dwarf KIC 08626021 to explore in detail the stability of its oscillation modes, searching, in particular, for evidence of nonlinear behaviors. Methods: We analyze nearly two years of uninterrupted short-cadence data, concentrating on identified triplets that are caused by stellar rotation and that show intriguing behaviors during the course of the observations. Results: We find clear signatures of nonlinear effects that could be attributed to resonant mode coupling mechanisms. These couplings occur between the components of the triplets and can induce different types of behaviors. We first notice that a structure at 3681 μHz, identified as a triplet in previous published studies, is in fact forming a doublet, with the third component being an independent mode. We find that a triplet at 4310 μHz and this doublet at 3681 μHz (most likely the two visible components of an incomplete triplet) have clear periodic frequency and amplitude modulations, which are typical of the so-called intermediate regime of the resonance, with timescales consistent with theoretical expectations. Another triplet at 5073 μHz is likely in a narrow transitory regime in which the amplitudes are modulated while the frequencies are locked. Using nonadiabatic pulsation calculations, based on a model representative of KIC 08626021 to evaluate the linear growth rates of the modes in the triplets, we also provide quantitative information that could be useful for future comparisons with numerical solutions of the amplitude equations. Conclusions: The observed modulations are the clearest hints of nonlinear resonant couplings occurring in white dwarf stars identified so far. These should resonate as a warning to projects that aim at measuring the evolutionary cooling rate of KIC 08626021, and of white dwarf stars in general. Nonlinear modulations of the frequencies can potentially jeopardize any attempt to measure such rates reliably, unless they can be corrected beforehand. These results should motivate further theoretical work to develop the nonlinear stellar pulsation theory. [less ▲]

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See detailAlors, on change ! Spéciale Climat COP21
Ozer, Pierre ULg

Speech/Talk (2016)

Catégorie: Vie quotidienne Programme: Alors on change ! Description Alors On Change ! sera à Paris pour la COP21... avec des propositions inspirantes pour nous aider à changer notre comportement et à ... [more ▼]

Catégorie: Vie quotidienne Programme: Alors on change ! Description Alors On Change ! sera à Paris pour la COP21... avec des propositions inspirantes pour nous aider à changer notre comportement et à relever le défi climatique. L'occasion sera belle de faire la chasse aux idées reçues et d'insister sur notre capacité individuelle à agir. Au programme, 3 portraits, un invité expert en bilan carbone et le tout présenté au coeur de happenings concoctés par des participants à la COP21, invités ou pas, désireux de faire de cette "grand-messe" autre chose qu'un chapelet de voeux pieux ! Pour vous éclairer, un graphique mettra en perspective l'impact en émission CO2 de différents secteurs d'activité (transport, consommation, travail, placements financiers...). Il servira de base pour faire une chasse aux idées reçues et sera explicité par son auteur, Frédéric Chômé, expert en bilan carbone : - Non, ce n'est pas le transport qui pollue le plus. - Oui, c'est notre épargne, si petite soit-elle, qui est le bras de levier le plus puissant pour réduire nos émissions CO2. Et cela ne signifie pas pour autant qu'un geste de non-consommation ou consommation responsable n'en vaille pas la peine : "Avec le climat, on parle de tout : de sciences, de philosophie, de sociologie, d'économie, de justice,... Donc, on doit tout changer dans un monde englué dans une triple inertie, à la fois politique, technologique et comportementale", affirme Pierre Ozer, géographe de ULg. " Alors, on change ! " s'est toujours appuyée sur les citoyens qui ont changé de comportement et cela reste le principe fondamental de la ligne éditoriale pour cette spéciale COP21 qui dressera le portrait de trois d'entre eux. - Uwe et son compagnon sont végétariens, en passe de devenir végétaliens. Ce couple vivant en communauté germanophone a le respect ancré en lui : respect de soi, des autres et des autres espèces. Renoncer à la viande, voire aux autres protéines animales ? Bien plus qu'un symbole... Un portrait réalisé par Aurélie Michel, journaliste à Télévesdre. - Pierret System est une PME spécialisée en portes et châssis à Transinne. Son patron Jean-Luc s'est adressé à Factor X, une autre PME, pour établir son bilan carbone et chercher des pistes pour réduire son empreinte. Récupérer et recycler les portes et châssis que l'entreprise remplace en est une qui emmène cette entreprise sur un modèle d'économie circulaire. Un portrait signé Antoine Masson, de TVLux. - Antoine a pris conscience de l'impact en CO2 de ses placements financiers et a décidé d'en reprendre le contrôle. Il est devenu animateur de groupes d'investisseurs pour Financité... Un portrait rêvé par Isabelle Salesse et Olivier Appart (RTBF). En dressant trois portraits, chacun ancré dans une réalité spécifique (consommation, travail, placements financiers), " Alors, on change ! " propose trois voies inspirantes. Libre à chacun d'agir là où il se sent le plus inspiré... En mettant en valeur les happenings de la COP 21 plutôt que les discours qui s'y tiennent, l'émission choisit de mettre l'accent sur l'engagement citoyen de celles et ceux qui veulent que le monde change. [less ▲]

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See detailInsan her şeyin ölçüsü şüdür? Çağdas dünya ısiğinda Protagoras
Gavray, Marc-Antoine ULg

in Sabah Ülkesi (2016), 46

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See detailDes légumes sur le bitume : L'agriculture urbaine est en plein développement
Jijakli, Haissam ULg

Article for general public (2016)

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