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See detailInfluence de l'évolution de la phytotechnie du blé sur le raisonnement de la protection fongicide
Bodson, Bernard ULg; Meeus, Patrick; Falisse, André

in Conférence internationale sur les maladies des plantes (1997, December 03)

Au cours de la dernière décennie, le rendement des cultures de blé a largement progressé essentiellement grâce à l'amélioration génétique et aux performances accrues en matière de fertilisation et de ... [more ▼]

Au cours de la dernière décennie, le rendement des cultures de blé a largement progressé essentiellement grâce à l'amélioration génétique et aux performances accrues en matière de fertilisation et de protection de la culture. L'amélioration génétique a petit à petit transformé la plante de blé: l'accroissement du potentiel de rendement repose principalement sur l'amélioration des composantes du rendement déterminées tardivement: fertilité des épis et capacité de remplissage des grains. La part de matière sèche produite à partir du stade dernière feuille devient prépondérante. La fertilisation azotée de la culture s'adapte à cette évolution: report d'une partie de la fumure en cours de montaison (France), renforcement de la fraction de la fumure apportée au stade dernière feuille (Belgique). Le glissement d'une part de la fumure azotée vers des stades plus avancés de la culture modifie les données de l'interaction entre les maladies cryptogamiques et la fumure la pression des maladie diminue en début de montaison mais s'accentue en fin de végétation. Dès lors, les programmes de protection fongicides devraient privilégier la protection des organes supérieurs de la plante: dernière feuille et épi. Les nouveaux fongicides de la famille des strobilurines sont dans cette optique des outils très intéressants. [less ▲]

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See detailSortir des ghettos culturels
Martiniello, Marco ULg

Scientific conference (1997, December 02)

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See detailCoherent and random sequences in financial fluctuations
Vandewalle, Nicolas ULg; Ausloos, Marcel ULg

in Physica A: Statistical Mechanics and its Applications (1997), 246(3-4), 454-459

The detrended fluctuation analysis (DFA) is used to sort out temporal correlations in financial data. Its usefulness for the investigations of long-range power-law correlations in economic sequences is ... [more ▼]

The detrended fluctuation analysis (DFA) is used to sort out temporal correlations in financial data. Its usefulness for the investigations of long-range power-law correlations in economic sequences is shown. Our findings of persistent and antipersistent sequences are surprisingly similar to those for DNA sequences which appeared as a mosaic of coding and non-coding patches. [less ▲]

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See detailDistinct Signal Transduction Pathways Mediate Nuclear Factor-Kappab Induction by Il-1beta in Epithelial and Lymphoid Cells
Bonizzi, Giuseppina; Piette, Jacques ULg; Merville, Marie-Paule ULg et al

in Journal of Immunology (1997), 159(11), 5264-72

We previously demonstrated that IL-1beta-mediated induction of the nuclear factor-kappaB (NF-kappaB) transcription factor proceeds through the production of reactive oxygen intermediates in lymphoid cells ... [more ▼]

We previously demonstrated that IL-1beta-mediated induction of the nuclear factor-kappaB (NF-kappaB) transcription factor proceeds through the production of reactive oxygen intermediates in lymphoid cells, while it occurs independently of any oxidative stress in epithelial transformed cells. Indeed, inhibition of receptor internalization as well as NH4Cl and chloroquine blocked IL-1beta-mediated induction of NF-kappaB in OVCAR-3 and in other epithelial cell lines but not in lymphoid cells, indicating that distinct pathways are involved. Conversely, while we observed phospholipase A2 activity in both cell types following IL-1beta stimulation, specific inhibitors of this enzyme inhibited NF-kappaB induction only in lymphoid cells. Moreover, expression of the 5-lipoxygenase (5-LOX) enzyme was not detected in epithelial cells, and inhibition of this enzyme blocked NF-kappaB induction by IL-1beta only in lymphoid cells. This study thus indicates that the activation of NF-kappaB following IL-1beta treatment involves the activation of phospholipase A2 and 5-LOX and the production of reactive oxygen intermediates (ROIs) in lymphoid cells, while in epithelial cells, another pathway predominates and could involve the acid sphingomyelinase. Moreover, arachidonic acid could induce NF-kappaB in epithelial and lymphoid cells, but this activation involved the 5-LOX enzyme and the production of ROIs only in lymphoid cells. The inefficiency of the ROI pathway in epithelial cells is probably the consequence of both low ROI production due to undetectable expression of 5-LOX and rapid degradation of hydrogen peroxide due to high catalase activity. [less ▲]

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See detailLes constellations (V).
Renson, Pierre ULg

in Ciel et Terre (1997), 113

Not Available

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See detailESO & NOT photometric monitoring of the Cloverleaf quasar
Ostensen, R.; Remy, M.; Lindblad, P. O. et al

in Astronomy and Astrophysics. Supplement Series (1997), 126

The Cloverleaf quasar, H1413+117, has been photometrically monitored at ESO (La Silla, Chile) and with the NOT (La Palma, Spain) during the period 1987--1994. All good quality CCD frames have been ... [more ▼]

The Cloverleaf quasar, H1413+117, has been photometrically monitored at ESO (La Silla, Chile) and with the NOT (La Palma, Spain) during the period 1987--1994. All good quality CCD frames have been successfully analysed using two independent methods (i.e. an automatic image decomposition technique and an interactive CLEAN algorithm). The photometric results from the two methods are found to be very similar, and they show that the four lensed QSO images vary significantly in brightness (by up to 0.45 mag), nearly in parallel. The lightcurve of the $D$ component presents some slight departures from the general trend which are very likely caused by micro-lensing effects. Upper limits, at the 99% confidence level, of 150 days on the absolute value for the time delays between the photometric lightcurves of this quadruply imaged variable QSO, are derived. This is unfortunately too large to constrain the lens model but there is little doubt that a better sampling of the lightcurves should allow to accurately derive these time delays. Pending a direct detection of the lensing galaxy (position and redshift), this system thus constitutes another good candidate for a direct and independent determination of the Hubble parameter. Based on observations collected at the European Southern Observatory (La Silla, Chile) and with the Nordic Optical Telescope (La Palma, Spain). Table 1. Logbook for the ESO and NOT observations together with photometric results for the Cloverleaf quasar. This long table can be accessed on the WWW at the URL address: http://vela.astro.ulg.ac.be/grav_lens/glp_homepage.html} [less ▲]

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See detailSmall-angle neutron scattering studies of low polarity telechelic ionomer solutions. 2. Single chain scattering
Karayianni, Eleni; Jérôme, Robert ULg; Cooper, Stuart L

in Macromolecules (1997), 30(24), 7444-7455

A direct probe of the single chain conformation in associating low polarity model telechelic ionomer solutions has been obtained using small-angle neutron scattering. A contrast matching technique was ... [more ▼]

A direct probe of the single chain conformation in associating low polarity model telechelic ionomer solutions has been obtained using small-angle neutron scattering. A contrast matching technique was employed utilizing a solution of hydrogenated and deuterated ionomer chains in a mixture of labeled and unlabeled solvent molecules. The scattering data at all concentrations and ionic levels examined show an excellent fit to the wormlike chain model. Single chain scattering patterns were obtained for two sodium-neutralized carboxy−telechelic polystyrene ionomers that differ by a factor of 2 in their molecular weight, in a concentration range from the dilute to the concentrated solution regime. The single chain dimensions were found to be influenced by both the ionic interactions and the extent of association. Both ionomer systems showed a contraction of the chain dimensions in the dilute solution regime which is more pronounced for the lower molecular weight telechelic ionomer. As concentration increases, the single chain dimensions increase until they reach a plateau value in the concentrated solution regime. This plateau value is very close to the chain dimensions of the ionomer in the bulk, as was found from a previous SANS study on similar ionomer systems. This plateau value chain dimension is also the same as the unperturbed dimension of the nonionic parent polymer in the bulk. The effect of concentration on the ionomer chain dimensions is attributed to the influence of ionic interactions as the nonionic form of the material shows larger chain dimensions in the concentration regime studied. These results indicate that intramolecular interactions with the formation of self loops prevail in the dilute solution regime. Intermolecular interactions with ionic groups connecting to different chains prevail in the concentrated solution regime, as evidenced by an extension of the chain dimensions. [less ▲]

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See detailDifunctional anionic initiator based on 1.3-diisopropenylbenzene. 5. Effect of polar additives and initiator seeding on the synthesis of poly(styrene-b-butadiene-b-styrene) copolymer
Yu, Y. S.; Dubois, Philippe ULg; Teyssié, Philippe et al

in Macromolecules (1997), 30(24), 7356-7362

The initiation of butadiene and styrene polymerization by a pure hydrocarbon soluble difunctional organolithium, 1,3-bis(1-lithio-1,3,3‘-trimethylbutyl)benzene, has been studied in a hydrocarbon solvent ... [more ▼]

The initiation of butadiene and styrene polymerization by a pure hydrocarbon soluble difunctional organolithium, 1,3-bis(1-lithio-1,3,3‘-trimethylbutyl)benzene, has been studied in a hydrocarbon solvent. The initiation occurs in such a way that part of the diadduct remains unreacted. When a second monomer feed along with tetrahydrofuran (THF) is added to the living chains, the residual diadduct is activated to the point where novel chains are formed. Weakly polar additives such as lithium alkoxides and aromatic ether can prevent part of the initiator from being inactive, although these additives are not effective enough to initiate the controlled synthesis of poly(styrene-b-butadiene-b-styrene) (SBS) triblock copolymers. The seeding of the initiator which consists of butadiene oligomerization in the presence of anisole and tBuOLi in cyclohexane, has proved to be very efficient in providing SBS containing 85% 1,4-microstructure polybutadiene (PBD) and with high mechanical properties, e.g., ultimate tensile strength higher than 30 MPa and elongation at a break of 1000%. [less ▲]

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See detailSpectroscopic analysis of the Alpha Centauri system
Neuforge-Verheecke, C.; Magain, Pierre ULg

in Astronomy and Astrophysics (1997), 328

A detailed spectroscopic analysis of the two components of the binary system alpha Centauri has been carried out on the basis of extensive high resolution and high signal-to-noise spectra. The ... [more ▼]

A detailed spectroscopic analysis of the two components of the binary system alpha Centauri has been carried out on the basis of extensive high resolution and high signal-to-noise spectra. The temperatures of the stars have been determined from the Fei excitation equilibrium and checked from the H_alpha line wings. The abundances of 17 elements have been obtained and indicate a general overabundance of 0.24 dex relative to the Sun, with no significant difference between the two stars. All elements analysed, from CNO to the iron peak, show basically the same overabundance. Only nickel seems to be significantly more overabundant, while the neutron capture elements appear less enhanced. Based on observations carried out at the European Southern Observatory (La Silla, Chile) [less ▲]

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See detailInfluence des hautes pressions hydrostatiques sur la congélation-décongélation de la viande de porc.
Massaux, Carine; Bera, François ULg; Steyer, Bénédicte et al

Poster (1997, December)

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See detailDirectional solidification by appropriate chemically active single crystal seed: An alternative way of generating large superconducting 123 single domain
Cloots, Rudi ULg; Auguste, F. X.; Rulmont, André ULg et al

in Journal of Materials Research (1997), 12(12), 3199-3202

A Dy2O3 single crystal has been used as a seed for the growth of isothermally melt-textured DY-123 material. The nucleation-controlled step has been observed to be related to the heterogeneous nucleation ... [more ▼]

A Dy2O3 single crystal has been used as a seed for the growth of isothermally melt-textured DY-123 material. The nucleation-controlled step has been observed to be related to the heterogeneous nucleation of 211 particles at the surface of the dysprosium oxide single crystal. The subsequent growth mode seems to be controlled by a high concentration gradient of dysprosium in the liquid phase. This leads to a directional solidification process of the 123 phase. The size of the 211 particles seems to decrease as the distance from the dysprosium oxide single crystal increases. [less ▲]

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See detailResilience, desistance and delinquent career of adolescent offenders
Born, Michel ULg; Chevalier, V.; Humblet, I.

in Journal of Adolescence (1997), 20(6), 679-694

This study examines resilience and desistance from delinquent behaviours and attempts to identify factors which predict persistent or increased or decreased delinquency between adolescence and early ... [more ▼]

This study examines resilience and desistance from delinquent behaviours and attempts to identify factors which predict persistent or increased or decreased delinquency between adolescence and early childhood. A sample of 363 young people was obtained from the population of five public institutions in 1987 and 1992. Their delinquent trajectories were described on the basis of legal records. These suggested that resilience is a rare phenomenon and is associated with stable relationships, absence of diagnostic label and good adaptation to the institution. Two axes were identified which can be used to describe the population, the family background and the psychological characteristics of the individual. Information which predicted desistance from a delinquent career was identified by means of a stepwise multiple regression. Analyses were conducted separately for each age group to take account of differences in time after the placement. The results indicated that there are important age-related differences in the characteristics which influence desistance or risk. They also show length of stay in an institution to be a predictor. Desistance from further delinquency seems to depend on the time spent in the residential environment associated with an increase of guilt, an improvement of self-image and of attachment to one or more other people. [less ▲]

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See detailState-of-the-art of photorefractive holographic interferometry and potentialities for space applications
Georges, Marc ULg; Lemaire, Philippe; Launay, Jean-Claude et al

in Otrio, G. (Ed.) Proceedings of CNES International Conference on Space Optics '97 (1997, December)

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See detailL'Univers est l'avenir de l'homme
Nazé, Yaël ULg

Article for general public (1997)

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See detailMorphometric Study of the Equine Navicular Bone: Comparisons between Fore and Rear Limbs
Gabriel, Annick ULg; Yousfi, S.; Detilleux, Johann ULg et al

in Zentralblatt für Veterinarmedizin. Reihe A (1997), 44(9-10), 579-94

Navicular bones collected from the four limbs of 95 sound horses were studied. The anatomic bases have been laid down about morphometry of the navicular bones and their variations according to limbs ... [more ▼]

Navicular bones collected from the four limbs of 95 sound horses were studied. The anatomic bases have been laid down about morphometry of the navicular bones and their variations according to limbs, after corrections have been made for morphologic type, gender, weight, size and age. All the dimensions of the navicular bone (except for the thickness) were larger in the fore limb. This phenomenon probably reflects an attempt to compensate for the greater forces exerted upon the fore limbs during exercise and at rest. Navicular bones collected from the four limbs of 61 sound horses were studied and the anatomic bases were described for histomorphometry of the fore and rear navicular bones. Fore navicular bones possess less cortical bone at the level of the articular surface, as well as at the level of the flexor surface and proximal border, but larger amounts of cancellous bone. Articular and flexor surface cortical bone show a larger porosity in the fore navicular bones and a larger amount of mineralized cartilage. The mineralized portion for distal impar- and collateral sesamoidean ligaments are also larger for the fore navicular bones. Two distinct zones are observed for the flexor surface cortex that have never been reported in the literature before: an external zone, which is mainly composed of poorly remodelled lamellar bone, arranged in a disto-proximal oblique direction, and an internal zone, which is mainly composed of secondary bone, with a latero-medial direction of Haversian canals. Bone architecture is discussed with regard to the mechanic load, encountered by the bone during locomotion. [less ▲]

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See detailComparison between Three- and Four-Element Windkessel Models to Characterize Vascular Properties of Pulmonary Circulation
Lambermont, Bernard ULg; Gérard, Paul ULg; Detry, Olivier ULg et al

in Archives of Physiology & Biochemistry (1997), 105(7), 625-32

In 11 anaesthetised pigs the accuracy of the three-element (WK3) and the four-element (WK4) Windkessel models to describe hemodynamic properties of the pulmonary circulation was compared during six ... [more ▼]

In 11 anaesthetised pigs the accuracy of the three-element (WK3) and the four-element (WK4) Windkessel models to describe hemodynamic properties of the pulmonary circulation was compared during six different experimental conditions increasing pulmonary arterial pressure: increase in left atrial pressure, increase in alveolar pressure, increase in pulmonary blood flow, endotoxin shock, mechanical obstruction of left pulmonary artery or histamine infusion. Our results showed that WK4 fitted better the data than did WK3 because values of 1-R2 decreased from 6 percent (WK3) to 1.4 percent (WK4) when WK4 was used (P < 0.0005). 1-R2 was an adequate marker of the accuracy of the linear regression used to solve equations of both models. Compliance values estimated by WK4 were decreased by 5% comparatively to WK3 (P = 0.008). However, this difference can be considered as not physiologically relevant. Values of characteristic resistance corresponding to R1 + (L/R2C) in WK4 and to R1 in WK3 were not different (P = 0.22). The relative changes in R1, R2, and C observed due to the different experimental conditions were comparable regardless of the model. In conclusion, the conversion of WK3 in WK4 by adding an inductance, whose physiological meaning is not clear, resulted in an increased statistical accuracy of the model, but did not seem to have relevant influence on parameters or their evolution during experimental conditions. [less ▲]

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See detailDigestibility and fermentation of inulin in the weaned piglets digestive tract.
Rossi, Florence; Ewodo, C.; Fockedey, R. et al

in Proceedings of the International Symposium " Non-digestible oligosaccharides : healthy food for the colon?" (1997, December)

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