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See detailStudies of the Domains II and III of Bacillus subtilis PBP4a in relation with the protein localization
Vanden Broeck, Arnaud ULg; Van Der Heiden, Edwige ULg; Sauvage, Eric ULg et al

Poster (2014, April 23)

Bacillus subtilis PBP4a belongs to the class-C1 PBPs characterized by two internal additional domains of unknown function. Seven lysine residues (K) are protruding from domain II. Four of them have been ... [more ▼]

Bacillus subtilis PBP4a belongs to the class-C1 PBPs characterized by two internal additional domains of unknown function. Seven lysine residues (K) are protruding from domain II. Four of them have been mutated in glutamine residues (Q). Both proteins (WT and Mut4KQ PBP4a) have been produced without signal peptide in E. coli and their sub-cellular localizations determined by measuring the DD-carboxypeptidase activities in the different compartments (cytoplasmic vs membrane attached proteins). In order to detect a possible influence of the PBP4a domain III in the localization of the protein, its encoding sequence has been cloned into pET-28b-BlaP, a vector allowing the production of WT BlaP β-lactamase or BlaP/DIII chimeric protein (with domain III inserted in a permissive loop of BlaP). The nitrocefin hydrolysis activities of BlaP or BlaP/DIII have been measured in the different cellular compartments. [less ▲]

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See detailThe archeological context of the last Neandertals and first Modern Humans in Europe
Flas, Damien ULg

Scientific conference (2014, April 23)

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See detailL'approche par compétences dans le cours de droit matériel européen
Sibony, Anne-Lise ULg

Diverse speeche and writing (2014)

Cette vidéo expose un exemple de mise ne oeuvre de l'approche par compétences dans le cadre d'un cours de droit européen (cours de 3ème année donné à 200 étudiants) et des séances d'exercices ... [more ▼]

Cette vidéo expose un exemple de mise ne oeuvre de l'approche par compétences dans le cadre d'un cours de droit européen (cours de 3ème année donné à 200 étudiants) et des séances d'exercices correspondantes. Elle est accompagnée d'un document qui illustre le propos par des exemples concrets (conseils donnés aux étudiants, corrigé d'exercice, grille d'évaluation). [less ▲]

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Peer Reviewed
See detailLe psychopathe : apprésentation, chosification de l’alter ego et compétences émotionnelles
Englebert, Jérôme ULg

Conference (2014, April 23)

La psychopathie est une entité diagnostique « trouble », tant au sein de la tradition psychopathologique que dans les nosographies internationales contemporaines (DSM-IV et DSM-V). Le modèle faisant ... [more ▼]

La psychopathie est une entité diagnostique « trouble », tant au sein de la tradition psychopathologique que dans les nosographies internationales contemporaines (DSM-IV et DSM-V). Le modèle faisant autorité en psychologie forensic est celui développé par R.D. Hare (2003) à travers une échelle diagnostique appelée PCL-R. Ce modèle rencontre, d’un point de vue théorique, plusieurs apories, et, d’un point de vue clinique, de nombreuses impasses. Nous proposons de réaliser un exercice de compréhension psychopathologique axé sur notre pratique clinique en nous inspirant des recommandations du courant de la psychopathologie phénoménologique (Minkowski, 1966 ; Binswanger, 1960 ; Stanghellini, 2006 ; Sass, Parnas & Zahavi, 2011). Celui-ci suggère de procéder par la mise en évidence de la structure psychopathologique qui organise le fonctionnement psychologique du sujet. De façon plus précise, nous centrerons notre propos sur deux dimensions essentielles à l’être-au-monde psychopathique. D’une part, nous réaliserons une comparaison avec l’être-au-monde maniaque à travers les variables de l’apprésentation et de la chosification de l’alter ego – telles que les développe Binswanger (1960). Nous discuterons, d’autre part, du vécu émotionnel propre à la psychopathie qui est davantage source d’adaptation (du moins en certaines situations) que de carence véritable. Ce constat nous permettra de rediscuter brièvement de la notion d’empathie en psychopathologie. Nous verrons que ces dimensions propres à l’existence psychopathique font apparaitre une thématique explicitement absente de la nosographie de Hare, celle de la morale. [less ▲]

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See detailSpatio-Temporal Analysis of Equatorial Ionospheric Scintillations in the Frame of Absolute GNSS Positioning Algorithms
Lonchay, Matthieu ULg; Cornet, Yves ULg; Aquino, Marcio et al

Poster (2014, April 23)

The ionosphere has always been a major limitation for GNSS positioning applications. Free electrons in the ionosphere perturb the propagation of GNSS radio signals involving both refraction and ... [more ▼]

The ionosphere has always been a major limitation for GNSS positioning applications. Free electrons in the ionosphere perturb the propagation of GNSS radio signals involving both refraction and diffraction effects. The ionospheric refraction mainly results in a modification of the propagation speed of the GNSS electromagnetic signals, inducing an error (propagation delay or phase advance depending on the observable) in GNSS measurements. In the frame of absolute positioning techniques, single-frequency algorithms usually exploit an ionospheric model to mitigate the ionospheric error while dual-frequency algorithms, such as the well-known Precise Point Positioning (PPP), take the benefit of the availability of two frequencies and the fact that the ionosphere is a dispersive medium to construct an ionosphere-free mathematical model. But these two strategies are not able to counteract the effect of the ionospheric diffraction which is due to small-scale irregularities in the free electron density. By scattering GNSS signals, these irregularities generate rapid fluctuations (scintillations) in the amplitude and phase of GNSS signals with critical consequences for GNSS applications: cycle slips, signal power fading, receiver loss of lock and poor resulting satellite geometry. The goal of our research is to develop a strategy to mitigate the effect of ionospheric scintillations on absolute GNSS positioning techniques, in particular the SPP (Standard Point Positioning) and the PPP (Precise Point Positioning). The strategy is based on the adjustment of the stochastic model. In order to construct the stochastic model (diagonal and non-diagonal elements) and study the correlation between observables, we adopted a “spatial” and an “empirical” approach. The spatial approach consists in a study of the spatial autocorrelation existing in scintillations effects on GNSS signals. The spatial autocorrelation is detected by using specific spatial analysis techniques applied on data from a network of ISMR (Ionospheric Scintillation Monitoring Receiver) stations located at equatorial and polar latitudes, where scintillations effects are most severe. The knowledge of how scintillation effects are spatially correlated is helpful for determining a coherent stochastic model. The empirical approach does not take into account the phenomenon spatiality and the locations of the measurements but only the observation data. Its objective is to determine the statistical correlation which exists between GNSS measurements during a scintillation event by using a moving filter applied on GNSS observation and scintillation data. The spatial approach exploits data and data locations while the empirical approach is based only the data itself. [less ▲]

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See detailDavid Knoke, Economic networks
Dufays, Frédéric ULg

in Lectures (2014)

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See detailLes institutions bleges à l'aube des élections du 25 mai 2014
Grandjean, Geoffrey ULg

Conference given outside the academic context (2014)

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Peer Reviewed
See detailElaboration of drug nanocarriers based on a glucosamine labeled amphiphilic polymer
Boyère, Cédric; Duhem, N; Debuigne, Antoine ULg et al

in Polymer Chemistry (2014), 5(8), 3030-3037

A new functional polymer micelle with high loading efficiency of a poorly soluble drug was made of biocompatible and/or biosourced compounds, i.e. cholesterol-poly(ethylene glycol)-glucosamine (Chol-PEG ... [more ▼]

A new functional polymer micelle with high loading efficiency of a poorly soluble drug was made of biocompatible and/or biosourced compounds, i.e. cholesterol-poly(ethylene glycol)-glucosamine (Chol-PEG-GlcNH2). A synthesis strategy combining enzymatic and metal-free click chemistry was developed in order to meet the increasingly stringent requirements of biomedical applications. After the self-assembly of the Chol-PEG-GlcNH2 amphiphilic polymer in water, the presence of glucosamine at the micelle surface confers an active targeting moiety to the nanocarriers whereas protonation of the peripheral primary amine delay their aggregation. The complete characterization of this novel functional amphiphilic bioconjugate is presented as well as its aqueous solution behaviour and encapsulation efficiency using ketoconazole as a model hydrophobic drug. [less ▲]

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See detailLa Belgique, un pays complexe
Hermans, Michel ULg

in Perdigon, Marie-France (Ed.) Actes des VIIème entretiens sur l'identité européenne (2014, April 19)

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See detailParticipation au Jury du Festival philosophique du Film "Eidolon" (concours "lycéens" et "pro")
Herla, Anne ULg

Diverse speeche and writing (2014)

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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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