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See detailThe non-trivial dispersion of Y2BaCuO5 particles trapped in the YBa2Cu3O7-x crystal matrix
Vandewalle, Nicolas ULg; Pirard, E.; Cloots, Rudi ULg et al

in Philosophical Magazine Letters (1998), 77(5), 301-306

Micrographs of melt-textured YBa2Cu3O7-x/Y2BaCuO5 (123/211) have been digitized. Through image analysis, we point out that the dispersion of the 211 particles is highly inhomogeneous in the melt and in ... [more ▼]

Micrographs of melt-textured YBa2Cu3O7-x/Y2BaCuO5 (123/211) have been digitized. Through image analysis, we point out that the dispersion of the 211 particles is highly inhomogeneous in the melt and in the 123 crystal matrix. Indeed, free 211 particle regions and 211 aggregates are observed. The distribution laws are given. Moreover, the dispersions of 211 particles in the melt and those trapped in the crystal matrix are quite different. We point out that this difference cannot be explained solely by the partial dissolution of the 211 particles during the growth process. [less ▲]

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See detailNon-uniform adaptive vertical grids for 3D numerical ocean models
Hofmeister, R.; Burchard, H.; Beckers, Jean-Marie ULg

in Ocean Modelling (2010), 33

A new strategy for the vertical gridding in terrain-following 3D ocean models is presented here. The vertical grid adaptivity is partially given by a vertical diffusion equation for the vertical layer ... [more ▼]

A new strategy for the vertical gridding in terrain-following 3D ocean models is presented here. The vertical grid adaptivity is partially given by a vertical diffusion equation for the vertical layer positions, with diffusivities being proportional to shear, stratification and distance from the boundaries. In the horizontal, the grid can be smoothed with respect to z-levels, grid layer slope and density. Lagrangian tendency of the grid movement is supported. The adaptive terrain-following grid can be set to be an Eulerian–Lagrangian grid, a hybrid r–q or r–z grid and combinations of these with great flexibility. With this, internal flow structures such as thermoclines can be well resolved and followed by the grid. A set of idealised examples is presented in the paper, which show that the introduced adaptive grid strategy reduces pressure gradient errors and numerical mixing significantly. The grid adaption strategy is easy to implement in various types of terrain-following ocean models. The idealised examples give evidence that the adaptive grids can improve realistic, long-term simulations of stratified seas while keeping the advantages of terrain-following coordinates. [less ▲]

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See detailNon-uniform adaptive vertical grids in one-dimensional numerical ocean models
Burchard, Hans; Beckers, Jean-Marie ULg

in Ocean Modelling (2004), 6(1), 51-81

It is demonstrated in this paper how the concept of general vertical coordinates can be exploited for constructing adaptive grids in primitive equation ocean models. The term adaptive is used here in the ... [more ▼]

It is demonstrated in this paper how the concept of general vertical coordinates can be exploited for constructing adaptive grids in primitive equation ocean models. The term adaptive is used here in the sense of coordinate iso-surfaces which follow certain internal structures of the flow in such a way that higher vertical resolution is obtained in locations where vertical gradients are large. The internal structures considered here are shear and stratification. In this paper, one-dimensional models are applied in order to demonstrate the ability of such grid adaptation methods to follow internal structures even in flow situations dominated by vertical mixing processes. Here, a variational approach is considered for the generation of grids which results in a diffusion equation for the vertical coordinate. The method is tested for five different idealised and realistic scenarios with the result that the discretisation error can be significantly reduced in comparison to equidistant Cartesian grids. Some recommendations for extending these methods for three-dimensional models are given at the end of this paper. (C) 2003 Elsevier Science Ltd. All rights reserved. [less ▲]

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See detailNon-uniqueness of the natural and projectively equivariant quantization
Radoux, Fabian ULg

in Journal of Geometry & Physics (2008), 58

In [C. Duval, V. Ovsienko, Projectively equivariant quantization and symbol calculus: Noncommutative hypergeometric functions, Lett. Math. Phys. 57 (1) (2001) 61–67], the authors showed the existence and ... [more ▼]

In [C. Duval, V. Ovsienko, Projectively equivariant quantization and symbol calculus: Noncommutative hypergeometric functions, Lett. Math. Phys. 57 (1) (2001) 61–67], the authors showed the existence and the uniqueness of a sl(m+1,R)-equivariant quantization in non-critical situations. The curved generalization of the sl(m+1,R)-equivariant quantization is the natural and projectively equivariant quantization. In [M. Bordemann, Sur l’existence d’une prescription d’ordre naturelle projectivement invariante (submitted for publication). math.DG/0208171] and [Pierre Mathonet, Fabian Radoux, Natural and projectively equivariant quantizations by means of Cartan connections, Lett. Math. Phys. 72 (3) (2005) 183–196], the existence of such a quantization was proved in two different ways. In this paper, we show that this quantization is not unique. [less ▲]

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See detailNon-visual brain sensitivity to light in aging
Daneault, V; Vandewalle, Gilles ULg; Hébert, M et al

Poster (2011, March)

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See detailNonadiabatic observables in main sequence delta Scuti stars
Moya, A.; Garrido, R.; Dupret, Marc-Antoine ULg

in IAU Colloq. 193: Variable Stars in the Local Group (2004, May 01)

Using a theoretical nonadiabatic pulsation model, phase differences and amplitude ratios between the relative effective temperature variation and the relative radial displacement have been calculated ... [more ▼]

Using a theoretical nonadiabatic pulsation model, phase differences and amplitude ratios between the relative effective temperature variation and the relative radial displacement have been calculated. These quantities, when compared with photometric observations in different colors, provide an efficient instrument for mode identification, the first step to understand the internal structure of the stars. The theoretical results presented in this paper show a dependence for delta Scuti stars on the mixing length parameter alpha used to treat the convection using the standard Mixing Length Theory. The nonadiabatic pulsational code developed here includes the pulsation atmosphere interaction as described by Dupret et al. (2002). The equilibrium models are provided by the CESAM evolutionary code, where a complete reconstruction of non-grey atmospheres (Kurucz models) is included. [less ▲]

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See detailNONADIABATIC UNIMOLECULAR REACTIONS .2. ISOTOPE EFFECTS ON THE KINETIC-ENERGY RELEASE
Remacle, Françoise ULg; Dehareng, Dominique ULg; Lorquet, Jean-Claude ULg

in Journal of Physical Chemistry (1988), 92(16), 4784-4787

This paper investigates the isotope effect that occurs when XOCO+ ions dissociate into XOC+ + 0 on a microsecond time scale (X = H or D). The reaction mechanism involves an electronic spin-forbidden ... [more ▼]

This paper investigates the isotope effect that occurs when XOCO+ ions dissociate into XOC+ + 0 on a microsecond time scale (X = H or D). The reaction mechanism involves an electronic spin-forbidden predissociation between a stable singlet state and a repulsive triplet. Application of the statistical equations developed in the previous paper shows that, at a given energy, the predissociation rate constant is consistently smaller for DOCO’ than for HOCO+. Therefore, the internal energy necessary to bring about dissociation of the hydrogenated compound with a given rate constant is always lower than that of the deuteriated compound by a quantity AE* which is found to be equal to ca. 0.050 eV when k = lo6 s-l and to ca 0.020 eV for k = lo3 s-1. As a result, the excess energy which is released as kinetic energy carried by the fragments is substantially greater for the deuteriated than for the hydrogenated compound. This accounts for experiments which indicate that, in the microsecond time scale, DOCO’ gives rise to a dished metastable peak whereas the corresponding signal for HOCO’ is simply Gaussian. [less ▲]

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See detailNonadiabatic Unimolecular Reactions of Polyatomic Molecules
Desouter-Lecomte, Michèle ULg; Dehareng, Dominique ULg; Leyh-Nihant, Brigitte et al

in Journal of Physical Chemistry (1985), 89

The nonadiabatic couplings which arise when two potential energy surfaces of a polyatomic molecule get close in energy can be classified as follows: (A) avoided crossings, (B) genuine intersections (Jahn ... [more ▼]

The nonadiabatic couplings which arise when two potential energy surfaces of a polyatomic molecule get close in energy can be classified as follows: (A) avoided crossings, (B) genuine intersections (Jahn-Teller and conical), (C) glancing intersections (Renner-Teller interactions). The characteristics of the potential energy surfaces in the adiabatic and diabatic representations are discussed for each case. The three coupling cases differ in the structure of the Hamiltonian matrix. When the latter is written in the diabatic representation, it is meaningful to retain the leading term only in its power series expansion. This gives rise to a so-called minimum-order model which is found to be surprisingly accurate (at least in a restricted zone of nuclear coordinates) when compared to the results of ab initio calculations. The characteristic features of each coupling case can only be understood in a two-dimensional configuration space, Le., when two nuclear degrees of freedom, often with different symmetry properties, are explicitly considered. A simple expression of the nonadiabatic transition probability between two electronic states can be worked out in the framework of the minimum-order models. Two-dimensional extensions of the Landau-Zener formula are obtained, which can be used to study the consequences of the anisotropic properties of the coupling. In the case of avoided crossings, only nuclear trajectories having a well-defined direction are able to bring about surface hopping, wheras there exists two active degrees of freedom for conical intersections. Hence, nonadiabatic processes which are controlled by genuine intersections are expected to take place faster than those controlled by avoided crossings. [less ▲]

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See detailNonalcoholic steatohepatitis and insulin resistance: interface between gastroenterologists and endocrinologists.
Scheen, André ULg; Luyckx, Françoise ULg

in Acta Clinica Belgica (2003), 58(2), 81-91

Nonalcoholic steatohepatitis (NASH), along with other forms of nonalcoholic fatty liver disease, is an increasingly common clinico-pathological syndrome. It is frequently associated with obesity ... [more ▼]

Nonalcoholic steatohepatitis (NASH), along with other forms of nonalcoholic fatty liver disease, is an increasingly common clinico-pathological syndrome. It is frequently associated with obesity, especially visceral fat, and type 2 diabetes, and is intimately related to markers of the insulin resistance syndrome. Both the prevalence and the severity of liver steatosis are related to body mass index, waist circumference, hyperinsulinaemia, hypertriglyceridemia and impaired glucose tolerance. The pathophysiology of NASH involves two steps: 1) insulin resistance, which causes steatosis; 2) and oxidative stress, which produces lipid peroxidation and activates inflammatory cytokines. The identification of subjects who may progress from fatty liver to NASH, and from NASH to fibrosis/cirrhosis is an important clinical challenge as well as the finding of appropriate therapy that could prevent such deleterious process. Substantial weight loss is accompanied by a marked attenuation of insulin resistance and related metabolic syndrome and, concomitantly, by an important regression of liver steatosis in most patients, although mild inflammation may be detected in some subjects. Thus, NASH may be considered as another disease of affluence, as is the insulin resistance syndrome and perhaps being part of it. [less ▲]

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See detailNonaqueous capillary electrophoresis method for the enantiomeric purity determination of S-timolol using heptakis(2,3-di-O-methyl-6-O-sulfo)-beta-cyclodextrin: validation using the accuracy profile strategy and estimation of uncertainty.
Marini Djang'Eing'A, Roland ULg; Servais, Anne-Catherine ULg; Rozet, Eric ULg et al

in Journal of Chromatography. A (2006), 1120(1-2), 102-11

Nonaqueous capillary electrophoresis (NACE) was successfully applied to the enantiomeric purity determination of S-timolol maleate using heptakis(2,3-di-O-methyl-6-O-sulfo)-beta-cyclodextrin (HDMS-beta-CD ... [more ▼]

Nonaqueous capillary electrophoresis (NACE) was successfully applied to the enantiomeric purity determination of S-timolol maleate using heptakis(2,3-di-O-methyl-6-O-sulfo)-beta-cyclodextrin (HDMS-beta-CD) as chiral selector. With a background electrolyte made up of a methanolic solution of 0.75 M formic acid, 30 mM potassium camphorsulfonate and containing 30 mM HDMS-beta-CD, the determination of 0.1% of R-timolol in S-timolol could be performed with an enantiomeric resolution of 8.5. Pyridoxine was selected as internal standard. The NACE method was then fully validated by applying a novel strategy using accuracy profiles. It is based on beta-expectation tolerance intervals for the total measurement error which includes trueness and intermediate precision. The uncertainty of measurements derived from beta-expectation tolerance intervals was estimated at each concentration level of the validation standards. To confirm the suitability of the developed and validated method, several real samples of S-timolol maleate containing R-timolol maleate at different concentrations were analysed and the results were compared to those obtained by liquid chromatography. [less ▲]

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See detailNonaqueous capillary electrophoretic behavior of 2-aryl propionic acids in the presence of an achiral ionic liquid - A chemometric approach
Francois, Yannis; Varenne, Anne; Juillerat, Emilie et al

in Journal of Chromatography. A (2007), 1138(1-2), 268-275

Ionic liquids (ILs) appear really attractive as electrolyte additives in nonaqueous capillary electrophoresis (NACE). These salts may offer new possibilities of interactions to modulate analyte effective ... [more ▼]

Ionic liquids (ILs) appear really attractive as electrolyte additives in nonaqueous capillary electrophoresis (NACE). These salts may offer new possibilities of interactions to modulate analyte effective mobilities. The presence of 1-n-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (BMIM NTf2) in acetonitrile/alcohol background electrolytes (BGEs) was investigated in this work. The aim of this study was to elucidate the influence of the IL concentration on the electrophoretic behavior of four arylpropionic acids and to identify the interactions between the analytes and the 1L cation. The influence on mobility of the IL concentration, the nature and the proportion of the organic solvents, and the concentration of the ionic components of the BGE was first studied by a univariate approach. A four-factor D-optimal experimental design was then applied to provide a deeper insight into analyte interaction with IL cation present both free in BGE and adsorbed onto the capillary wall. (c) 2006 Elsevier B.V. All rights reserved. [less ▲]

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See detailNonaqueous electrokinetic chromatography-electrospray ionization mass spectrometry using anionic cyclodextrins
Mol, Roelof; Servais, Anne-Catherine ULg; Fillet, Marianne ULg et al

in Journal of Chromatography. A (2007), 1159(1-2), 51-57

The set-up of an on-line method for coupling nonaqueous electrokinetic chromatography (NAEKC) and electrospray ionization mass spectrometry (ESI-MS) is presented. It allows the use of the single-isomer ... [more ▼]

The set-up of an on-line method for coupling nonaqueous electrokinetic chromatography (NAEKC) and electrospray ionization mass spectrometry (ESI-MS) is presented. It allows the use of the single-isomer derivative anionic cyclodextrins heptakis(2,3-di-O-methyl-6-O-sulfo)-beta-cyclodextrin (HDMS-beta-CD) and heptakis(2.3-di-O-acetyl-6-O-sulfo)-beta-cyclodextrin (HDAS-beta-CD) for chiral and achiral separations of positively charged analytes. The effect of the cyclodextrins (CDs) on the MS signal intensities of model compounds was studied. When a voltage is applied over the CE capillary, the overall mobility of the CDs is towards the inlet vial preventing CDs from entering the ion source. However, the sodium counter ions of the CDs still enter the ion source and appeared to cause ionization suppression. Nevertheless, significant analyte signals could still be detected with detection limits in the sub-mu g/ml. System parameters such as sheath liquid composition and flow rate, nebulizing gas pressure, capillary position in the sprayer and the drying gas flow and temperature were studied and optimized. The selection of a relatively low nebulizing gas pressure appeared to be important to achieve optimum sensitivity. The chiral selectivity of the NAEKC-ESI-MS system could be improved by addition of camphorsulfonate to the background electrolyte. Using mixtures of drugs and drug-related compounds, the NAEKC-ESI-MS system is shown to offer potential for (chiral) drug profiling. (c) 2007 Elsevier B.V. All rights reserved. [less ▲]

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See detailThe Noncatalytic Triad of Alpha-Amylases: A Novel Structural Motif Involved in Conformational Stability
Marx, J. C.; Poncin, J.; Simorre, J. P. et al

in Proteins (2008), 70(2), 320-328

Chloride-activated alpha-amylases contain a noncatalytic triad, independent of the glycosidic active site, perfectly mimicking the catalytic triad of serine-proteases and of other active serine hydrolytic ... [more ▼]

Chloride-activated alpha-amylases contain a noncatalytic triad, independent of the glycosidic active site, perfectly mimicking the catalytic triad of serine-proteases and of other active serine hydrolytic enzymes. Mutagenesis of Glu, His, and Ser residues in various alpha-amylases shows that this pattern is a structural determinant of the enzyme conformation that cannot be altered without losing the intrinsic stability of the protein. (1)H-(15)N NMR spectra of a bacterial alpha-amylase reveal proton signals that are identical with the NMR signature of catalytic triads and especially a deshielded proton involving a protonated histidine and displaying properties similar to that of a low barrier hydrogen bond. It is proposed that the H-bond between His and Glu of the noncatalytic triad is an unusually strong interaction, responsible for the observed NMR signal and for the weak stability of the triad mutants. Furthermore, a stringent template-based search of the Protein Data Bank demonstrated that this motif is not restricted to alpha-amylases, but is also found in 80 structures from 33 different proteins, amongst which SH2 domain-containing proteins are the best representatives. [less ▲]

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See detailLe nonce et le confesseur princier: jeux d'influence au sein des Pays-Bas espagnols durant la première moitié du xviie siècle
Pirlet, Pierre-François ULg

in Revista de la Inquisicion (2012), 16

À Bruxelles, à la cour des archiducs puis des Gouverneurs-généraux, le confesseur princier est vu comme un personnage influent. Les nonces, soutenus par la secrétairerie d'État romaine, vont développer ... [more ▼]

À Bruxelles, à la cour des archiducs puis des Gouverneurs-généraux, le confesseur princier est vu comme un personnage influent. Les nonces, soutenus par la secrétairerie d'État romaine, vont développer, au cours du xviie siècle, un ensemble de stratégies pour faire de ce personnage la pièce maîtresse de leur action. Ces religieux, quant à eux, se considèrent plutôt comme les serviteurs de la Couronne espagnole, dont les intérêts ne sont pas toujours en phase avec ceux de la papauté. Cette étude vise à démontrer l'asymétrie de la relation entre confesseurs et diplomates romains. [less ▲]

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See detailNonclinical Participants' Reports of Hallucinatory Experiences
Laroi, Frank ULg; Van der Linden, Martial ULg

in Canadian Journal of Behavioural Science = Revue Canadienne des Sciences du Comportement (2005), 37

Hallucinatory experiences in nonclinical subjects were examined using a French adaptation of a self-report questionnaire (Launay-Slade Hallucinations Scale; LSHS). The factor structure of this ... [more ▼]

Hallucinatory experiences in nonclinical subjects were examined using a French adaptation of a self-report questionnaire (Launay-Slade Hallucinations Scale; LSHS). The factor structure of this questionnaire was examined. In addition to prevalence, we explored various characteristics of the reported hallucinatory experiences, including frequency, degree of control, emotional reaction, relationship to stressful events, and personal saliency. We also examined the relationship between the presence of hallucinatory experiences and other factors, such as substance use and social desirability. Two hundred and thirty-six nonclinical participants completed a modified version of the LSHS, a social desirability scale, and answered follow up questions. Factor analysis of the present version of the LSHS revealed a five-factor structure. Results regarding participants' hallucination frequency, perceived levels of control, and affective responses are reported. Additional results and implications are discussed. [less ▲]

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See detailNoncollinear magnetism and single-ion anisotropy in multiferroic perovskites
Weingart, C.; Spaldin, N.; Bousquet, Eric ULg

in Physical Review. B, Condensed Matter and Materials Physics (2012), 86(9),

The link between the crystal distortions of the perovskite structure and the magnetic exchange interaction, the single-ion anisotropy (SIA), and the Dzyaloshinsky-Moriya (DM) interaction are investigated ... [more ▼]

The link between the crystal distortions of the perovskite structure and the magnetic exchange interaction, the single-ion anisotropy (SIA), and the Dzyaloshinsky-Moriya (DM) interaction are investigated by means of density functional calculations. Using BiFeO 3 and LaFeO 3 as model systems, we quantify the relationship between the oxygen octahedra rotations, the ferroelectricity, and the weak ferromagnetism (wFM). We recover the fact that the wFM is due to the DM interaction induced by the oxygen octahedra rotations. We find a simple relationship between the wFM, the oxygen rotation amplitude, and the ratio between the DM vector and the exchange parameter such that the wFM increases with the oxygen octahedra rotation when the SIA does not compete with the DM forces induced on the spins. Unexpectedly, we also find that in spite of the d5 electronic configuration of Fe3 +, the SIA is very large in some structures and is surprisingly strongly sensitive to the chemistry of the A-site cation of the ABO 3 perovskite. In the ground R3c state phase we show that the SIA shape induced by the ferroelectricity and the oxygen octahedra rotations are in competition such that it is possible to turn the wFM "on" and "off" through the relative size of the two types of distortion. © 2012 American Physical Society. [less ▲]

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See detailNonconsumption of the reinforcer under drug action
Faidherbe, J.; Richelle, Marc ULg; Schlag, J.

in Journal of the Experimental Analysis of Behavior (1962), 5(4), 521-524

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See detailNonconventional radiographic projections in the equine orthopaedic examination
Richard, Eric ULg; Alexander, Kate

in Equine Veterinary Education (2007), 19(10), 551-559

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See detailNoncovalent functionalization of multi-walled carbon nanotubes by pyrene containing polymers
Petrov, Petar; Stassin, Fabrice; Pagnoulle, Christophe et al

in Chemical Communications (2003), (23), 2904-2905

Multi-walled carbon nanotubes (MWNTs) have been solubilized in water and in various organic solvents by noncovalent side-wall functionalization by pyrene containing polymers.

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