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See detailInactivation of genes coding for mitochondrial Nd7 and Nd9 complex I subunits in Chlamydomonas reinhardtii. Impact of complex I loss on respiration and energetic metabolism.
Massoz, Simon; Larosa, Véronique ULg; Plancke, Charlotte et al

in Mitochondrion (2013)

In Chlamydomonas, unlike in flowering plants, genes coding for Nd7 (NAD7/49kDa) and Nd9 (NAD9/30kDa) core subunits of mitochondrial respiratory-chain complex I are nucleus-encoded. Both genes possess all ... [more ▼]

In Chlamydomonas, unlike in flowering plants, genes coding for Nd7 (NAD7/49kDa) and Nd9 (NAD9/30kDa) core subunits of mitochondrial respiratory-chain complex I are nucleus-encoded. Both genes possess all the features that facilitate their expression and proper import of the polypeptides in mitochondria. By inactivating their expression by RNA interference or insertional mutagenesis, we show that both subunits are required for complex I assembly and activity. Inactivation of complex I impairs the cell growth rate, reduces the respiratory rate, leads to lower intracellular ROS production and lower expression of ROS scavenging enzymes, and is associated to a diminished capacity to concentrate CO2 without compromising photosynthetic capacity. [less ▲]

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See detailInactivation of nucleolin leads to nucleolar disruption, cell cycle arrest and defects in centrosome duplication.
Ugrinova, Iva; Monier, Karine; Ivaldi, Corinne et al

in BMC Molecular Biology (2007), 8

BACKGROUND: Nucleolin is a major component of the nucleolus, but is also found in other cell compartments. This protein is involved in various aspects of ribosome biogenesis from transcription regulation ... [more ▼]

BACKGROUND: Nucleolin is a major component of the nucleolus, but is also found in other cell compartments. This protein is involved in various aspects of ribosome biogenesis from transcription regulation to the assembly of pre-ribosomal particles; however, many reports suggest that it could also play an important role in non nucleolar functions. To explore nucleolin function in cell proliferation and cell cycle regulation we used siRNA to down regulate the expression of nucleolin. RESULTS: We found that, in addition to the expected effects on pre-ribosomal RNA accumulation and nucleolar structure, the absence of nucleolin results in a cell growth arrest, accumulation in G2, and an increase of apoptosis. Numerous nuclear alterations, including the presence of micronuclei, multiple nuclei or large nuclei are also observed. In addition, a large number of mitotic cells showed a defect in the control of centrosome duplication, as indicated by the presence of more than 2 centrosomes per cell associated with a multipolar spindle structure in the absence of nucleolin. This phenotype is very similar to that obtained with the inactivation of another nucleolar protein, B23. CONCLUSION: Our findings uncovered a new role for nucleolin in cell division, and highlight the importance of nucleolar proteins for centrosome duplication. [less ▲]

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See detailInactivation of rat liver RNA polymerases I and II and yeast RNA polymerase I by pyrodixal 5'-phosphate. Evidence for the participation of lysyl residues at the active site.
Martial, Joseph ULg; Zaldivar, J.; Bull, P. et al

in Biochemistry (1975), 14

Purified DNA-dependent RNA polymerase forms I (A) and II (B) from rat liver and form I from yeast are rapidly inactivated by pyridoxal 5'-phosphate at pH 8.0. The inhibition is relatively specific since ... [more ▼]

Purified DNA-dependent RNA polymerase forms I (A) and II (B) from rat liver and form I from yeast are rapidly inactivated by pyridoxal 5'-phosphate at pH 8.0. The inhibition is relatively specific since pyridoxamine 5'-phosphate is not an inhibitor and pyridoxal is about 12 times less effective than pyridoxal 5'-phosphate. The inactivation is reversed by high concentrations of amines, and can be made irreversible by reduction with NaBH4. Spectral analysis of the inhibited enzyme and its NaBH4 reduction product indicates that a Schiff base forms between the aldehyde group of pyridoxal 5'-phosphate and one or more amino groups of the protein. Nepsilon-Pyridoxyllysine was identified as the only product in acid hydrolysates of the reduced yeast RNA polymerase I-pyridoxal 5'-phosphate complex. Complete inactivation of yeast polymerase I results in the incorporation of 3-4 mol of pyridoxal 5'-phosphate/1 mol of enzyme. DNA and nucleotide substrates partially protect the enzymes from inactivation. These results suggest that one or more lysyl amino groups are critical for the activity of animal RNA polymerases and show that pyridoxal 5'-phosphate is a suitable probe for studying the active sites of these enzymes. Comparison of the present results with those previously obtained with Eschericha coli RNA polymerase in this laboratory suggest a new degree of structural homology between eucaryotic and procaryotic RNA polymerases. [less ▲]

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See detailThe inactive members of the aspartic proteinase family in the ruminant placenta: specificity of three different radioimmunoassay systems
Perenyi, Zsolt; Sulon, Joseph ULg; Szenci, Otto et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2001), 5(1), 26-27

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See detailInAs with wurtzite crystal structure: full-potential and psedopotential ab-initio calculations
Zanolli, Zeila ULg; von Barth, Ulf

in Luitz, Joachim; Hebert, Cecile; Weinmeier, Kerstin (Eds.) et al DFTEM2006 - bringing together two communities (2006)

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See detailInbreeding depression for global and partial economic indexes, production, type and functional traits in the Walloon Region of Belgium
Croquet, Coraline; Mayeres, Patrick; Gillon, Alain ULg et al

in INTERBULL Bulletin (2005), 33

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See detailInbreeding depression for global and partial economic indexes, production, type, and functional traits
Croquet, Coraline; Mayeres, Patrick; Gillon, Alain ULg et al

in Journal of Dairy Science (2006), 89(6), 2257-2267

The objective of this research was to examine the effects of inbreeding in the population of Holstein cattle in the Walloon region of Belgium. The effects of inbreeding on the global economic index and ... [more ▼]

The objective of this research was to examine the effects of inbreeding in the population of Holstein cattle in the Walloon region of Belgium. The effects of inbreeding on the global economic index and its components were studied by using data from the genetic evaluations of February 2004 for production, somatic cell score (SCS), computed from somatic cell counts and type. Inbreeding coefficients for 956,516 animals were computed using a method that allows assigning an inbreeding coefficient to individuals without known parents. These coefficients were equal to the mean inbreeding coefficient of contemporary individuals with known parents. The significance of inbreeding effects on the different evaluated traits and on the different indexes were tested using a t-test comparing estimated standard errors and effects. The inbreeding effect was significantly different from zero for the vast majority of evaluated traits and for all of the indexes. Inbreeding had the greatest deleterious effects on production traits. Inbreeding decreased yield of milk, fat, and protein during a lactation by 19.68, 0.96, and 0.69 kg, respectively, per each 1% increase in inbreeding. The regression coefficient of SCS per 1% increase in inbreeding was +0.005 SCS units. The inbreeding depression was thus relatively low for SCS, but inbred animals had higher SCS than non-inbred animals, indicating that inbred animals would be slightly more sensitive to mastitis than non-inbred animals. Estimates of inbreeding effects on evaluated type traits per 1% increase were small. The most strongly affected type traits were chest width, rear leg, and overall development on a standardized scale. For several type traits, particularly traits linked to the udder, the estimates suggested a favorable effect of inbreeding. The global economic index was depressed by around 6.13 Euro of lifetime profit per 1% increase in inbreeding for the Holstein animals in the Walloon region of Belgium. [less ▲]

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See detailLes incapacités
Leleu, Yves-Henri ULg

Book (2003)

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See detailL’incendie : feu purificateur ?
Close, Florence ULg

in Bulletin de la Société d'Art et d'Histoire du Diocèse de Liège (2013), LXX

Dans la nuit du 3 au 4 août 1312, la Cité de Liège est mise à feu et à sang. Sept siècles plus tard, la mémoire collective liégeoise compte encore cet évènement au nombre des jalons les plus tragiques de ... [more ▼]

Dans la nuit du 3 au 4 août 1312, la Cité de Liège est mise à feu et à sang. Sept siècles plus tard, la mémoire collective liégeoise compte encore cet évènement au nombre des jalons les plus tragiques de l’histoire de la Principauté. Les conditions dans lesquelles moururent les patriciens demeurent inqualifiables, de même que les moyens auxquels recourut la masse populaire révoltée pour venir à bout de son adversaire. Cet évènement anecdotique au regard de la grande histoire met en lumière la place ambivalente du feu dans la vie et la mentalité des hommes et des femmes du Moyen Âge. Il invite à une profonde réflexion mêlant des considérations juridiques, spirituelles, symboliques et anthropologiques [less ▲]

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See detailIncentive Effects on Risk Attitude in Small Probability Prospects
Lefebvre, Mathieu ULg; Villeval, Marie-Claire; Vieider, Ferdinand

E-print/Working paper (2009)

Most studies on the role of incentives on risk attitude report data obtained from within-subject experimental investigations. This may however raise an issue of sequentiality of effects as later choices ... [more ▼]

Most studies on the role of incentives on risk attitude report data obtained from within-subject experimental investigations. This may however raise an issue of sequentiality of effects as later choices may be influenced by earlier ones. This paper reports instead between-subject results on the effect of monetary stakes on risk attitudes for small probability prospects in a laboratory experiment. Under low stakes, we find the typical risk seeking behavior for small probabilities predicted by the prospect theory. But under high stakes, we provide some evidence that risk seeking behavior is dramatically reduced. This could suggest that utility is not consistently concave over the outcome space, but rather contains a convex section for very small amounts. [less ▲]

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See detailIncentive Effects on Risk Attitude in Small Probability Prospects
Lefebvre, Mathieu ULg; Vieider, Ferdinand; Villeval, Marie Claire

in Economics Letters (2010), 109(2),

We report between-subject results on the effect of monetary stakes on risk attitudes. While we find the typical risk seeking for small probabilities, risk seeking is reduced under high stakes. This ... [more ▼]

We report between-subject results on the effect of monetary stakes on risk attitudes. While we find the typical risk seeking for small probabilities, risk seeking is reduced under high stakes. This suggests that utility is not consistently concave. [less ▲]

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See detailIncentive salience attribution under reward uncertainty: A Pavlovian model
Anselme, Patrick ULg

in Behavioural Processes (2015), 111(1), 6-18

There is a vast literature on the behavioural effects of partial reinforcement in Pavlovian conditioning. Compared with animals receiving continuous reinforcement, partially rewarded animals typically ... [more ▼]

There is a vast literature on the behavioural effects of partial reinforcement in Pavlovian conditioning. Compared with animals receiving continuous reinforcement, partially rewarded animals typically show (a) a slower development of the conditioned response (CR) early in training and (b) a higher asymptotic level of the CR later in training. This phenomenon is known as the partial reinforcement acquisition effect (PRAE). Learning models of Pavlovian conditioning fail to account for it. In accordance with the incentive salience hypothesis, it is here argued that incentive motivation (or ‘wanting’) plays a more direct role in controlling behaviour than does learning, and reward uncertainty is shown to have an excitatory effect on incentive motivation. The psychological origin of that effect is discussed and a computational model integrating this new interpretation is developed. Many features of CRs under partial reinforcement emerge from this model. [less ▲]

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See detailIncentives for BGP Guided IP-Level Topology Discovery
Donnet, Benoît ULg

in First International Workshop on Traffic Monitoring and Analysis (2009, May)

Internet topology discovery has been an attractive research field during the past decade. In particular, the research community was interested in modeling the network as well as providing efficient tools ... [more ▼]

Internet topology discovery has been an attractive research field during the past decade. In particular, the research community was interested in modeling the network as well as providing efficient tools, mostly based on traceroute, for collecting data. In this paper, we follow this track of rendering traceroute-based exploration more efficient. We discuss incentives for coupling passive monitoring and active measurements. In particular, we show that high-level information, such as BGP updates, might be used to trigger targeted traceroutes. As a result, the network dynamics might be better capture. We also provide a freely available tool for listening to BGP feeds and triggering dedicated traceroutes. [less ▲]

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See detailIncentives in Organizations
Gautier, Axel ULg

Doctoral thesis (2001)

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See detailL’inceppo e l’affondo: Oralità e figure di ripetizione in Raffaello Baldini
Benzoni, Pietro ULg

in Strumenti Critici (2007), 113(1), 90-104

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See detailInception of Taeniate Bisaccates pollen: further evidence and age implications for the Monte Alegre Formation (Pennsylvanian, Amazon Basin).
Melo, JHG; Loboziak, S; Dino, R et al

in Annals Academia Brazil Cienca (1997)

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See detailIncertitudes liées à la modélisation agro-environnementale en vue de développer des outils d'aide à la décision
Dumont, Benjamin ULg

Doctoral thesis (2014)

The European Nitrates Directive 91/6/76/EEC aims to ensure water quality by preventing pollution of surface and groundwater induced by nitrates originating from agricultural sources and by promoting ... [more ▼]

The European Nitrates Directive 91/6/76/EEC aims to ensure water quality by preventing pollution of surface and groundwater induced by nitrates originating from agricultural sources and by promoting agronomical good practices. While the implementation of this Directive seems effective, it appears however that the use of nitrogen has still increased by 6% over the last four years in 27 European countries. Furthermore, agricultural sources would be still at the origin of 50% of the total amount of nitrogen discharged into surface waters (http://ec.europa.eu/environment/water/water-nitrates/index_en.html). In Wallonia (Belgium), the Nitrates Directive has been transposed under the Sustainable Nitrogen Management in Agriculture Program (PGDA). Launched in 2002, it involves different sets of actions, like rules definitions concerning fertilizers application, specific and appropriate crop management in vulnerable areas, the control of potentially leachable nitrogen (APL) levels in soils, etc. This is the global context in which lies the present thesis. The main aim is to optimise the nitrogen fertiliser practices to ensure that the needs of a winter wheat culture (Triticum aestivum L.) could be met while reducing the environmental pressure. It relies on the use of crop models, which describe the growth and the development of a culture interacting with its environment, namely the soil and the atmosphere. The major difficulty while working with crop models and model-based decision support tools lies in the fact that different sources of uncertainties have an impact on the modelled phenomena. Indeed, crop models are constituted by a consequent number of differential non-linear equations, involving a lot of parameters which need to be determined as accurately as possible in order to match as close as possible observed sequences of measurements. The first source of uncertainty is thus constituted by the parameters definition. Once the model has been correctly and robustly calibrated it can be used to perform predictions. However, in an agronomical context, the time-delay between sowing and harvest is consequent. As the end-season yield is often the expected output, the uncertainty linked to the non-knowledge of the future implies for the modeller to refer to different hypothesis concerning upcoming climatic scenarios. Finally, moving from models to decision systems dealing with N management involves a last source of uncertainty. Indeed the main problem is that the impact of a given practice is delayed in time from its realisation. In addition to the uncertainty linked to climatic projections themselves, it is highly important to consider the interactions between the practices and the climate. Furthermore, in a decision-making process, it could be highly relevant to know the uncertainty's estimation that could be tolerated on the decision.. Therefore, the present thesis aims to study these different sources of uncertainty in order to design an efficient decision support system. It is divided into five parts. In the first part, a Bayesian sampling algorithm, known as DREAM (DiffeRential Evolution Adaptative Metropolis) will be presented. It was successfully coupled with the STICS soil-crop model used in this study. The a posteriori probability density function of many parameters was sampled in order to improve the simulations of the growth of a winter wheat culture (Triticum aestivum L.). The DREAM algorithm offers different advantages in comparison to usual methods. Among these, it is possible to study i) the most probable a posteriori parameters distributions, ii) the parameters correlations, and iii) the uncertainties impacted on model outputs. Furthermore, a new version of the likelihood function was proposed, making an explicit use of the coefficient of variation. Results showed that it allowed the noise existing on measurements to be considered, but also the heteroscedasticity phenomenon usually encountered in biological growth processes. In parallel, assimilation data is another way to improve models simulations. These techniques allow considering measurements performed in real-time (e.g. remote measures of LAI or soil water content) in order to correct and adjust the possible drift of model simulations. In particular, a recently developed algorithm, known as variational filter, was evaluated. Its superiority, both in term of state variables simulations improvement and parameter resampling, was demonstrated. The third part of the research focuses on the real-time end season yield prediction. It involves building climate matrix ensembles, combining different time ranges of projected mean data and real measured weather originating from the historical records. As the crop growing season progresses, the effects of real monitored data plays a greater role and the prediction reliability increases. Our results demonstrated that a reliable predictive delay of 3-4 weeks before harvest could be obtained. Finally, using real-time data acquired with a micrometeorological station enabled to (i) predict, daily, potential yield at the local level, (ii) detect stress occurrence, and (iii) quantify yield losses (or gains). Being based on projected seasonal norms, this methodology is in opposition to another technique that consists to offer a panel of solution for what concerns the future. Such probabilistic technique relies on the use of stochastic weather generator (LARS-WG in this case). However, in the fourth part of this thesis, on the basis of the convergence in law theorem, it was demonstrated that in 90% of the climatic situations, both approaches were equivalent, exhibiting RRMSE and normalised deviation criteria inferior to 10%. Furthermore the two approaches offered similar predictive delay-time. The main difference between techniques lies in the finality. The first allows to quickly simulate the remaining yield potential, while the second aims to quantify the uncertainty level associated to the predictions. In the fifth and last part of this thesis, in order to quantify the uncertainty level associated to different modalities of N applications, the STICS model answers were studied under stochastic climatic realisations. It was demonstrated that, if no N was applied, under our temperate climatic conditions, the yield distribution could be considered as normal. However, with increasing N practices, the asymmetry level was found itself increasing. As soon as N was applied, not only were the yields higher, but also was the probability to achieve yields that were at least superior to the mean of the distribution. This undoubtedly reduced the risk for the farmer to achieve low yields levels. To summary all the researches conducted in this thesis, a N strategic decision support system was developed. In a general way, for what concerns the Hesbaye Region, the superiority of three fractions N protocols was demonstrated. In addition, the three rates fertilisation management based on the systematic applications of 60 kgN.ha-1 at tillering and stem extension stages and offering the possibility to adapt the flag-leaf fraction in real-time appeared as an optimal strategy. Within this tool, the uncertainty associated to climatic variability could be finely characterised, and the risk encountered by the farmer was quantified for different investigated practices. But far more important, it was demonstrated that N management could be optimised in real-time. In a general way, the research should be pursued by studying more fundamentally and systematically a wide range of different agro-environmental situations. In particular, it would be interesting to study of the Genotype × Environment × Cultural practices interactions to ensure food security in a climatic changing world. [less ▲]

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See detailIncertitudes sur l'habitus
Frère, Bruno ULg

in Archives Européennes de Sociologie = European Journal of Sociology = Europaisches Archiv für Soziologie (2005), XLVI(3), 469-494

Bourdieu fut le fondateur d’un paradigme structuraliste aujourd’hui appliqué à l’envi par certains sociologues et radicalement évincé par d’autres. Nous nous intéresserons ici aux tentatives ... [more ▼]

Bourdieu fut le fondateur d’un paradigme structuraliste aujourd’hui appliqué à l’envi par certains sociologues et radicalement évincé par d’autres. Nous nous intéresserons ici aux tentatives intermédiaires de Lahire et Corcuff qui, sans omettre de pointer des impasses, ont bien vu l’intérêt du concept d’habitus « singulier ». Après avoir repris leurs approches, nous proposerons une définition « fictionnelle » de cet habitus afin de rendre ce paradigme opérationnel sur des terrains pour lesquels sa capacité heuristique est faible (comme les nouveaux mouvements sociaux). Bourdieu was the founder of a structuralist paradigm which is now often applied by some sociologists and strongly criticised by others. We are interested here in the intermediate attempts of Lahire and Corcuff. Without omitting to notice some dead ends, they understood the interest of the "singular" habitus concept. After following their approach, we propose a "fictional" definition of this habitus in order to make this paradigm operational in areas where its heuristic capacity is low (like the new social movements). [less ▲]

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