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See detailBulletin agrométéorologique - Août 2005
Tychon, Bernard ULg; Ozer, Pierre ULg; De Longueville, Florence ULg et al

in Bulletin Agrométorologique (2005), 4(5), 1-4

Le mois d’août a été caractérisé par des valeurs climatiques proches de la normale. Cependant, les températures et les valeurs de rayonnement étaient anormalement faibles. Par rapport à l’année dernière ... [more ▼]

Le mois d’août a été caractérisé par des valeurs climatiques proches de la normale. Cependant, les températures et les valeurs de rayonnement étaient anormalement faibles. Par rapport à l’année dernière et, sur l’ensemble du territoire, les prévisions de rendements des principales cultures printanières sont équivalentes dans le cas de la betterave sucrière, et à la baisse pour le maïs fourrager et la pomme de terre Bintje. [less ▲]

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See detailMultiplication by a Constant and Recognizability in an Abstract Numeration System
Charlier, Emilie ULg

Poster (2005, September 12)

One of the main interesting concerns in work about numeration systems is studying the relationship that exist between arithmetic properties of numbers and syntactical properties of their representation ... [more ▼]

One of the main interesting concerns in work about numeration systems is studying the relationship that exist between arithmetic properties of numbers and syntactical properties of their representation. More precisely, we prefer to manipulate set of numbers whose representations are characterized by very simple syntactical rules, that is, forming a regular language. Such sets are called S-recognizable sets, where S is the numeration system we are working with. In particular, we would like to obtain numeration systems in which the whole set N is recognizable, partly due to the fact that, if the set of representations of all integers is regular, there are very simple algorithms making it possible to decide if a word stands or does not stand for a number. Some general questions in this area are the following. • Characterization of the recognizable parts in a fixed numeration system. • Determination of the numeration systems for which a given set of numbers is recognizable. • To examine the stability of recognizability under arithmetic operations. In this poster we present our research about that last problem. First, we will define the abstract numeration systems based on a regular language. Then we will study the relationship between multiplication by a constant and the S-recognizability for languages of the type a_1^∗ . . . a_k^∗. [less ▲]

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See detailVinyl acetate: a challenge for living radical polymerisation
Debuigne, Antoine ULg

Scientific conference (2005, September 11)

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See detailMolecular characterisation of a versatile peroxidase from a Bjerkandera strain
Moreira, Patricia R.; Duez, Colette ULg; Dehareng, Dominique ULg et al

in Journal of Biotechnology (2005), 118(4), 339-352

The cloning and sequencing of the rbpa gene coding for a versatile peroxidase from a novel Bjerkandera strain is hereby reported. The 1777 bp isolated fragment contained a 1698 bp peroxidase-encoding gene ... [more ▼]

The cloning and sequencing of the rbpa gene coding for a versatile peroxidase from a novel Bjerkandera strain is hereby reported. The 1777 bp isolated fragment contained a 1698 bp peroxidase-encoding gene, interrupted by 11 introns. The 367 amino acid-deduced sequence includes a 27 amino acid-signal peptide. The molecular model, built via homology modelling with crystal structures of four fungal peroxidases, highlighted the amino acid residues putatively involved in manganese binding and aromatic substrate oxidation. The potential heme pocket residues (R44, F47, H48, E79, N85, H177, F194 and D239) include both distal and proximal histidines (H48 and H177). RBP possesses potential calcium-binding residues (D49, G67, D69, S71, S178, D195, T197, I200 and D202) and eight cysteine residues (C3, C15, C16, C35, C121, C250, C286, C316). In addition, RIBP includes residues involved in substrate oxidation: three acidic residues (E37, E41 and D183)-putatively involved in manganese binding and H83 and W172-potentially involved in oxidation of aromatic substrates. Characterisation of nucleotide and amino acid sequences include RBP in versatile peroxidase group sharing catalytic properties of both UP and MnP. In addition, the RBP enzyme appears to be closely related with the ligninolytic peroxidases from the Trametes versicolor strain. (C) 2005 Published by Elsevier B.V. [less ▲]

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See detailFunctionalization of poly(epsilon-caprolactone) by pendant hydroxyl, carboxylic acid and epoxide groups by atom transfer radical addition
Riva, Raphaël ULg; Lenoir, Sandrine ULg; Jérôme, Robert ULg et al

in Polymer (2005), 46(19), 8511-8518

A straightforward strategy is proposed for grafting hydroxyl, carboxylic acid and epoxide groups along poly (epsilon-caprolactone) chains. Statistical copolymerization of epsilon-caprolactone (epsilon-CL ... [more ▼]

A straightforward strategy is proposed for grafting hydroxyl, carboxylic acid and epoxide groups along poly (epsilon-caprolactone) chains. Statistical copolymerization of epsilon-caprolactone (epsilon-CL) with alpha-chloro-epsilon-caprolactone (alpha-Cl-epsilon-CL) has been initiated by 2,2-dibutyl-2-stanna-1,3-dioxepane (DSDOP), followed by the atom transfer radical addition (ATRA) of but-3-en-1-ol, vinylacetic acid and 1,2-epoxyhex-5-ene, respectively, onto the alpha-chloro units of a poly(alpha-Cl-epsilon-CL-co-epsilon-CL) copolymer. alpha-Cl-epsilon-CL is easily prepared by the Baeyer-Villiger oxidation of 2-chlorocyclohexanone. The influence of the experimental conditions, i.e. temperature, solvent, catalyst, on the grafting yield has been discussed. Because ATRA is tolerant of the investigated functional groups, no protection/deprotection reaction is required, which is a major advantage of the method. [less ▲]

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See detailLe froment d'hiver
Vancutsem, Françoise ULg; Couvreur, Luc; Bodson, Bernard ULg et al

in Livre Blanc: Céréales - Gembloux - Informations avant les semis (2005, September 08)

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See detailEscourgeon et Orge d'hiver fourragers
Herman, Jean-Luc; Monfort, Bruno; Couvreur, Luc et al

in Livre Blanc: Céréales - Gembloux - Informations avant les semis (2005, September 08)

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See detailLa qualité des froments d'hiver en 2005?
Sinnaeve, Geoges; Lenartz, J.; Herman, Jean-Luc et al

in Livre Blanc: Céréales - Gembloux - Informations avant les semis (2005, September 08)

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See detailOr bleu / Or noir
BALTHASAR, JEAN PIERRE; COLLIGNON, FABRICE; DE WIT, PIERRE et al

Article for general public (2005)

Au grand mécontentement général, le prix du pétrole augmente irrésistiblement. Malgré cela, notre société ne semble pas disposée à changer ses habitudes. [...] Ces mois de vacances ont été riches en ... [more ▼]

Au grand mécontentement général, le prix du pétrole augmente irrésistiblement. Malgré cela, notre société ne semble pas disposée à changer ses habitudes. [...] Ces mois de vacances ont été riches en catastrophes climatiques. Ainsi, en Afrique de l'Ouest, des milliers de personnes ont disparu suite à une longue famine consécutive à un ciel resté trop longtemps avare en précipitations. En Méditerranée occidentale, on ne compte plus les milliers d'hectares de forêt partis en fumée à cause de la sécheresse. Au même moment, l'Europe centrale et orientale est lasse de patauger dans l'eau. Les spécialistes qualifient ces inondations comme étant les plus graves qu'aient connues la Suisse et la Roumanie. L'Inde est également noyée alors que Taïwan se prépare à la tempête la plus violente de son histoire. Et après ces préliminaires dramatiques, voici Katrina qui sème chaos et désolation. [...] [less ▲]

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See detailNatural and projectively equivariant quantizations
Radoux, Fabian ULg

Conference (2005, September 02)

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See detailVariabilité intra- et inter-races du profil en acides gras de la matière grasse du lait
Soyeurt, Hélène ULg

Master's dissertation (2005)

Currently there is no cattle selection program which is based on fatty acid profile in milk fat. According to several publications, both the saturated and insaturated fatty acids have positive as well as ... [more ▼]

Currently there is no cattle selection program which is based on fatty acid profile in milk fat. According to several publications, both the saturated and insaturated fatty acids have positive as well as negative effects on human health. So using overall milk fat as the only criteria in selection may be considered not appropriate. The aim of this research was to evaluate the potential effectiveness of selection on higher nutritional quality of milk fat. The variability within and across breeds for Dual Purpose Belgian Blue, Holstein-Friesian, Jersey, Montbeliarde and Red and White animals were analysed. The quantity of fatty acids in milk and milk fat was measured by medium infrared and were analysed using mixed model methodology; this analysis showed that several differences between the five dairy breeds for the profile of fatty acids exist. High repeatability estimates suggest that high additive genetic variance for fatty acid profile exists within each breeds. Moreover the variability for each component was demonstrated in the population. This first investigation showed that genetic improvement of the nutritional quality of milk fat, therefore on the fatty acid profile, is possible and researcher or development dairy selection progress is justified. [less ▲]

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See detailDeep Impact at ESO Telescopes
Kaufl, Hans-Ullrich; Ageorges, Nancy; Bagnulo, Stefano et al

in The Messenger (2005), 121

This article is a first summary of the observations done with ESO telescopes and instrumentation in the context of NASA's Deep Impact (DI) space mission. The ESO observers were part of an extremely active ... [more ▼]

This article is a first summary of the observations done with ESO telescopes and instrumentation in the context of NASA's Deep Impact (DI) space mission. The ESO observers were part of an extremely active, communicative and thus successful worldwide network of observers. Through this network all information was freely exchanged and highlights are reported here as well. [less ▲]

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See detailIsotopic abundances of carbon and nitrogen in Jupiter-family and Oort Cloud comets
Hutsemekers, Damien ULg; Manfroid, Jean ULg; Jehin, Emmanuel ULg et al

in Astronomy and Astrophysics (2005), 440(Letters), 21-24

The [SUP]12[/SUP]C[SUP]14[/SUP]N/[SUP]12[/SUP]C[SUP]15[/SUP]N and [SUP]12[/SUP]C[SUP]14[/SUP]N/[SUP]13[/SUP]C[SUP]14[/SUP]N isotopic ratios are determined for the first time in a Jupiter-family comet, 88P ... [more ▼]

The [SUP]12[/SUP]C[SUP]14[/SUP]N/[SUP]12[/SUP]C[SUP]15[/SUP]N and [SUP]12[/SUP]C[SUP]14[/SUP]N/[SUP]13[/SUP]C[SUP]14[/SUP]N isotopic ratios are determined for the first time in a Jupiter-family comet, 88P/1981 Q1 Howell, and in the chemically peculiar Oort Cloud comet C/1999 S4 (LINEAR). By comparing these measurements to previous ones derived for six other Oort Cloud comets (including one of Halley-type), we find that both the carbon and nitrogen isotopic ratios are constant within the uncertainties. The mean values are [SUP]12[/SUP]C/[SUP]13[/SUP]C ~= 90 and [SUP]14[/SUP]N/[SUP]15[/SUP]N ~=145 for the eight comets. These results strengthen the view that CN radicals originate from refractory organics formed in the protosolar molecular cloud and subsequently incorporated in comets. [less ▲]

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See detailMembrane-type 1 matrix metalloproteinase expression is regulated by zonula occludens-1 in human breast cancer cells
Polette, M.; Gilles, Christine ULg; Nawrocki-Raby, B. et al

in Cancer Research (2005), 65(17), 7691-7698

The acquisition of a migratory/invasive phenotype by tumor cells is characterized by the loss of cell-cell adhesion contacts and the expression of degradative properties. In this study, we examined the ... [more ▼]

The acquisition of a migratory/invasive phenotype by tumor cells is characterized by the loss of cell-cell adhesion contacts and the expression of degradative properties. In this study, we examined the effect of the disorganization of occludin/zomda occludens (ZO)-1 tight junction (TJ) complexes on the expression of membrane-type I matrix metalloproteinase (MT1-MMP). We first compared the expression of MT1-MMP and the localization of occludin/ZO-1 complexes in breast tumor cell lines displaying various degrees of invasiveness. We showed that the expression of MT1-MMP in invasive breast tumor cell lines correlates with the absence of occludin and with a cytoplasmic localization of ZO-1. In contrast, noninvasive cell lines displayed a membrane staining for both ZO-1 and occludin and did not express MT1-MMP. In vivo, cytoplasmic ZO-1 and MTI-MMP could be detected in invasive tumor clusters of human breast carcinomas. We then used RNA interference strategy to inhibit ZO-1 expression in invasive BT549 cells and to evaluate the effect of ZO-1 downregulation on MTI-MMP expression. We observed that ZO-1 small interfering RNA transfection down-regulates MT1-MMP mRNAs and proteins and subsequently decreases the ability of tumor cells to invade a reconstituted basement membrane in a Boyden chamber assay. Inversely, transfection of expression vectors encoding wild-type ZO-1 or the NH2-terminal fragment of ZO-1 comprising the PSD95/DLG/ZO-1 domains in BT549 activated a human MT1-MMP promoter luciferase reporter construct and increased cell invasiveness. Such transfections concomitantly activated the beta-catenin/TCF/LEF pathway. Our results therefore show that ZO-1, besides its structural role in TJ assembly, can intervene in signaling events promoting tumor cell invasion. [less ▲]

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See detailL'astronomie dans le monde
Manfroid, Jean ULg

Article for general public (2005)

Deep Impact, Mars, Le cratère Nicholson, 248 MARSIS, CLUSTER, Aurores de Saturne, Sylvia, Planète X (suite), Supernova de M51

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See detailAn asteroseismic study of the β Cephei star θ Ophiuchi: spectroscopic results
Briquet, Maryline ULg; Lefever, K.; Uytterhoeven, K. et al

in Monthly Notices of the Royal Astronomical Society (2005), 362

We present the results of a detailed analysis of 121 ground-based high-resolution, high signal-to-noise ratio spectroscopic measurements spread over 3 yr for the β Cephei star θ Ophiuchi. We discovered θ ... [more ▼]

We present the results of a detailed analysis of 121 ground-based high-resolution, high signal-to-noise ratio spectroscopic measurements spread over 3 yr for the β Cephei star θ Ophiuchi. We discovered θ Oph to be a triple system. In addition to the already known speckle B5 companion of the B2 primary, we showed the presence of a low-mass spectroscopic companion and we derived an orbital period of 56.71 d with an eccentricity of 0.1670. After removing the orbit we determined two frequencies for the primary in the residual radial velocities: f[SUB]1[/SUB]= 7.1160 cd[SUP]-1[/SUP] and f[SUB]2[/SUB]= 7.4676 cd[SUP]-1[/SUP]. We also found the presence of f[SUB]3[/SUB]= 7.3696 cd[SUP]-1[/SUP] by means of a two-dimensional frequency search across the SiIII 4567-Åprofiles. We identified the m-value of the main mode with frequency f[SUB]1[/SUB] by taking into account the photometric identifications of the degrees l. By means of the moment method and the amplitude and phase variations across the line profile, we derived (l[SUB]1[/SUB], m[SUB]1[/SUB]) = (2, -1). This result allows us to fix the mode identifications of the whole quintuplet for which three components were detected in photometry. This is of particular use for our forthcoming seismic modelling of the primary. We also determined stellar parameters of the primary by non-local thermodynamic equilibrium hydrogen, helium and silicon line profile fitting and we obtained T[SUB]eff[/SUB]= 24000 K and logg= 4.1, which is consistent with photometrically determined values. [less ▲]

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See detailChemical abundances in 43 metal-poor stars
Jonsell, K.; Edvardsson, B.; Gustafsson, B. et al

in Astronomy and Astrophysics (2005), 440

We have derived abundances of O, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Fe, Ni, and Ba for 43 metal-poor field stars in the solar neighbourhood, most of them subgiants or turn-off-point stars with iron ... [more ▼]

We have derived abundances of O, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Fe, Ni, and Ba for 43 metal-poor field stars in the solar neighbourhood, most of them subgiants or turn-off-point stars with iron abundances [Fe/H] ranging from -0.4 to -3.0. About half of this sample has not been spectroscopically analysed in detail before. Effective temperatures were estimated from uvby photometry, and surface gravities primarily from Hipparcos parallaxes. The analysis is differential relative to the Sun, and was carried out with plane-parallel MARCS models. Various sources of error are discussed and found to contribute a total error of about 0.1-0.2 dex for most elements, while relative abundances, such as [Ca/Fe], are most probably more accurate. For the oxygen abundances, determined in an NLTE analysis of the 7774 Å triplet lines, the errors may be somewhat larger. We made a detailed comparison with similar studies and traced the reasons for the, in most cases, relatively small differences. Among the results we find that [O/Fe] possibly increases beyond [Fe/H] = -1.0, though considerably less so than in results obtained by others from abundances based on OH lines. We did not trace any tendency toward strong overionization of iron, and find the excesses, relative to Fe and the Sun, of the alpha elements Mg, Si, and Ca to be smaller than those of O. We discuss some indications that also the abundances of different alpha elements relative to Fe vary and the possibility that some of the scatter around the trends in abundances relative to iron may be real. This may support the idea that the formation of Halo stars occurred in smaller systems with different star formation rates. We verify the finding by Gratton et al. (2003b, A&A, 406, 131) that stars that do not participate in the rotation of the galactic disk show a lower mean and larger spread in [ alpha/Fe] than stars participating in the general rotation. The latter stars also seem to show some correlation between [ alpha/Fe] and rotation speed. We trace some stars with peculiar abundances, among these two Ba stars, <ASTROBJ>HD 17072</ASTROBJ> and <ASTROBJ>HD 196944</ASTROBJ>, the second already known to be rich in s elements. Finally we advocate that a spectroscopic study of a larger sample of halo stars with well-defined selection criteria is very important, in order to add to the very considerable efforts that various groups have already made. [less ▲]

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See detailDeux ans d'analyse de saisies d'heroine en region liegeoise
Denooz, Raphael ULg; Dubois, Nathalie ULg; Charlier, Corinne ULg

in Revue Médicale de Liège (2005), 60(9), 724-8

The results of heroin analysis from seizures in the Liege area during the last two years are presented in this article. Between January 2003 and January 2005, 50 samples were analysed in the Laboratory of ... [more ▼]

The results of heroin analysis from seizures in the Liege area during the last two years are presented in this article. Between January 2003 and January 2005, 50 samples were analysed in the Laboratory of Clinical Toxicology and Forensic Toxicology of the University of Liege. Mean heroin concentration was 14,7%. Noscapine and papaverine, other opium alcaloids, were simultaneously present with heroin. As diluents, we only identified caffein and acetaminophen. [less ▲]

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See detailRole of disulfide bridges in the activity and stability of a cold-active alpha-amylase
Siddiqui, K. S.; Poljak, A.; Guilhaus, M. et al

in Journal of Bacteriology (2005), 187(17), 6206-6212

The cold-adapted alpha-amylase from Pseudoalteromonas haloplanktis unfolds reversibly and cooperatively according to a two-state mechanism at 30 degrees C and unfolds reversibly and sequentially with two ... [more ▼]

The cold-adapted alpha-amylase from Pseudoalteromonas haloplanktis unfolds reversibly and cooperatively according to a two-state mechanism at 30 degrees C and unfolds reversibly and sequentially with two transitions at temperatures below 12 degrees C. To examine the role of the four disulfide bridges in activity and conformational stability of the enzyme, the eight cysteine residues were reduced with beta-mercaptoethanol or chemically modified using iodoacetamide or iodoacetic acid. Matrix-assisted laser desorption-time of flight mass spectrometry analysis confirmed that all of the cysteines were modified. The iodoacetamide-modified enzyme reversibly folded/unfolded and retained approximately one-third of its activity. Removal of all disulfide bonds resulted in stabilization of the least stable region of the enzyme (including the active site), with a concomitant decrease in activity (increase in activation enthalpy). Disulfide bond removal had a greater impact on enzyme activity than on stability (particularly the active-site region). The functional role of the disulfide bridges appears to be to prevent the active site from developing ionic interactions. Overall, the study demonstrated that none of the four disulfide bonds are important in stabilizing the native structure of enzyme, and instead, they appear to promote a localized destabilization to preserve activity. [less ▲]

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See detailThe active site is the least stable structure in the unfolding pathway of a multidomain cold-adapted alpha-amylase
Siddiqui, K. S.; Feller, Georges ULg; D'Amico, Salvino ULg et al

in Journal of Bacteriology (2005), 187(17), 6197-6205

The cold-active alpha-amylase from the Antarctic bacterium Pseudoalteromonas haloplanktis (AHA) is the largest known multidomain enzyme that displays reversible thermal unfolding (around 30 degrees C ... [more ▼]

The cold-active alpha-amylase from the Antarctic bacterium Pseudoalteromonas haloplanktis (AHA) is the largest known multidomain enzyme that displays reversible thermal unfolding (around 30 degrees C) according to a two-state mechanism. Transverse urea gradient gel electrophoresis (TUG-GE) from 0 to 6.64 M was performed under various conditions of temperature (3 degrees C to 70 degrees C) and pH (7.5 to 10.4) in the absence or presence of Ca2+ and/or Tris (competitive inhibitor) to identify possible low-stability domains. Contrary to previous observations by strict thermal unfolding, two transitions were found at low temperature (12 degrees C). Within the duration of the TUG-GE, the structures undergoing the first transition showed slow interconversions between different conformations. By comparing the properties of the native enzyme and the N12R mutant, the active site was shown to be part of the least stable structure in the enzyme. The stability data supported a model of cooperative unfolding of structures forming the active site and independent unfolding of the other more stable protein domains. In light of these findings for AHA, it will be valuable to determine if active-site instability is a general feature of heat-labile enzymes from psychrophiles. Interestingly, the enzyme was also found to refold and rapidly regain activity after being heated at 70 degrees C for 1 h in 6.5 M urea. The study has identified. fundamental new properties of AHA and extended our understanding of structure/stability relationships of cold-adapted enzymes. [less ▲]

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