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See detailRole of transcription factor sox4b in the differentiation of pituitary cells in zebrafish.
Quiroz O' Donova, Yobhana ULg

Doctoral thesis (2014)

The pituitary is a complex gland comprising different cell types each secreting specific hormones. The extensive network of signaling molecules and transcription factors required for determination and ... [more ▼]

The pituitary is a complex gland comprising different cell types each secreting specific hormones. The extensive network of signaling molecules and transcription factors required for determination and terminal differentiation of specific cell types is still not fully understood. The SRY-like HMG-box (SOX) transcription factor Sox4 plays important roles in many developmental processes and has two homologs in zebrafish, Sox4a and Sox4b. We show that the sox4b gene is expressed in the pituitary anlagen starting at 24hpf and later in the entire head region including the pituitary. At 48hpf, sox4b mRNA colocalizes with that for thyroid stimulating hormone (tsh), glycoprotein subunit  (gsu) and the Zn finger transcription factor Gata2a. Loss of Sox4b function, using morpholino knock-down or expression of a dominant negative Sox4 mutant, leads to a drastic decrease in tsh and gsu expression and reduced levels of gh, while other anterior pituitary gland markers including prl, slβ, pomc and lim3 are not affected. Sox4b is also required for expression of gata2a in the pituitary. Knockdown of gata2a leads to decreased tsh and gsu expression at 48hpf, similar to sox4b morphants. Injection of gata2a mRNA into sox4b morphants rescued tsh and gsu expression in thyrotrope cells. Finally, sox4b or gata2a knockdown causes a significant decrease of gonadotropin expression (lhβ and fshβ) at 4dpf. In summary, our results indicate that Sox4b is expressed in zebrafish during pituitary development and plays a crucial role in the differentiation of thyrotrope and gonadotrope cells through induction of gata2a expression in the developing pituitary. [less ▲]

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See detailBiorefine: Recovery of nutrients and metallic trace elements from different wastes by chemical and biochemical processes
Tarayre, Cédric ULg; Fischer, Christophe ULg; De Clercq, Lies et al

Conference (2014, June 05)

At present, most waste processing operations are not oriented towards the valorization of valuable reusable components such as nitrogen, phosphorus, potassium and even Metallic Trace Elements (MTEs ... [more ▼]

At present, most waste processing operations are not oriented towards the valorization of valuable reusable components such as nitrogen, phosphorus, potassium and even Metallic Trace Elements (MTEs). Currently, sewage sludge, for example is usually used as a fertilizer in agriculture, in energy production or in the field of construction. Ashes originating from sludge incineration contain heavy metals and minerals in large quantities. Manure is mainly used in agriculture, although considerable amounts of nutrients are lost and cause pollution. Digestate is also used in agriculture, but other alternatives have been proposed, such as the energetic valorization. Better valorization of these wastes in agriculture (or other sectors) is however largely constrained by a multitude of legal requirements. An important problematic point is the concentration in MTEs that is found in those wastes. Consequently, recovery of nutrients and MTEsmay be a key solution for optimal valorization of wastes. Many unit operations used in the field of chemical and biochemical engineering (mechanical operations on fluids, solids, mass and heat transfers, chemical reactions, etc.) could be used in order to achieve an efficient recovery yield of nutrients and trace elements. The aim of the BioRefine Project is to make an inventory of all recovery techniques of nutrients and MTEs in five countries: Belgium, France, Germany, United Kingdom and The Netherlands. Pilot plants will also be tested to assess the efficiency of new treatment techniques after which the most efficient processes will be chosen to be applied on a larger scale. In addition, the collected data will be used to propose exploitation scenarios taking into account legal constraints and optimized logistics.This work is supported through an INTERREG IVB NWE programme(ref. 320J-BIOREFINE). [less ▲]

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See detailExploration du récit de vie d’adolescents
Poudat, Céline; Boulard, Aurore ULg

in Née, Emilie; Daube, Jean-Michel; Valette, Mathieu (Eds.) et al Proceedings-actes des 12èmes journées d'analyse statistique de données textuelles (2014, June 05)

The present paper follows on from the research we presented in previous JADT (Boulard, Poudat, Gauthier 2012). We still focus on the development of narrative competence (Habermas et Bluck 2000) in ... [more ▼]

The present paper follows on from the research we presented in previous JADT (Boulard, Poudat, Gauthier 2012). We still focus on the development of narrative competence (Habermas et Bluck 2000) in children and adolescents. Although children develop narrative skills, life narratives only emerge in adolescence. On the basis of a corpus made of spontaneous oral speech, we had empirically demonstrated that pre-adolescents aged of 12 had developed stabilized narrative skills enabling them to produce life narratives. Here, we propose a first exploration of the overall structure of adolescent life stories, thanks to a corpus of 268 oral self narratives completed with a questionnaire. [less ▲]

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See detailThe application of the NSGA-II optimization method in designing control charts
Faraz, Alireza ULg; Heuchenne, Cédric ULg; Seif, Asghar

Scientific conference (2014, June 04)

The problem of designing control chart is formulated as a multi-objective optimization problem with the adjusted average time to signal as the statistical objective and the expected cost per hour as the ... [more ▼]

The problem of designing control chart is formulated as a multi-objective optimization problem with the adjusted average time to signal as the statistical objective and the expected cost per hour as the economic objective. Then we try to find the Pareto-optimal designs in which the two objectives are minimized simultaneously by using the elitist non-dominated sorting genetic algorithm method. Through an illustrative example, the advantages of the proposed approach is shown by providing a list of viable optimal solutions and graphical representations, thereby bolding the advantage of flexibility and adaptability. [less ▲]

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See detailL'épaule un carrefour complexe
WANG, François-Charles ULg; LOZZA, Alessandro

Conference (2014, June 04)

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See detailApproche socio-écologique: arrangements de la complexité
Absil, Gaëtan ULg

Conference (2014, June 04)

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See detailUn autre regard sur la vieillesse
Adam, Stéphane ULg

Conference given outside the academic context (2014)

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See detailElectrical characterization of pGeSn/nGe diodes
Baert, Bruno ULg; Gupta, Somya; Gencarelli, Federica et al

Conference (2014, June 03)

I-V characteristics of pGeSn/nGe diodes have been measured and show very good properties. Simulations of the same structure are able to reproduce most of the observed behavior and point to the ... [more ▼]

I-V characteristics of pGeSn/nGe diodes have been measured and show very good properties. Simulations of the same structure are able to reproduce most of the observed behavior and point to the predominating influence of parameters such as the band gap energy of the GeSn layer. C-V characteristics showing little frequency dependence have also been measured, and their analysis for the determination of the carrier concentration is confirmed by simulations. More investigations, including the effect of temperature and other defects at the interface or in the bulk of either layers are still required in order to explain some of the observed behaviors, notably the reverse saturation current. [less ▲]

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See detailUn chiffre en débat. Controverse autour de la dette wallonne
Piron, Damien ULg

Conference (2014, June 03)

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See detailSIMPLIFIED SEISMIC ANALYSIS OF LOCK GATES
Buldgen, Loïc ULg; Degée, Hervé ULg; Lesourne, Hervé et al

in PIANC 2014 Conference (2014, June 02)

The paper deals with the seismic design of lock gates. When such structures are submitted to an earthquake, the water contained in the chamber is responsible for an additional hydrodynamic pressure acting ... [more ▼]

The paper deals with the seismic design of lock gates. When such structures are submitted to an earthquake, the water contained in the chamber is responsible for an additional hydrodynamic pressure acting on the gate. This one is the sum of three different parts, respectively called the convective, rigid and flexible contributions. The two first ones have already been extensively studied in the literature, but the flexible part is more difficult to assess as it is largely influenced by the coupling occurring between the fluid and the gate. To overcome this difficulty, it is of course possible to use finite elements software, but doing so is not always convenient. This is why some research have been undertaken to provide a rapid way for approximating the flexible pressure on lock gates. This is achieved by applying the analytical approach that is shortly presented in this paper. As a matter of validation, the results obtained through this simplified procedure are compared to numerical solutions. The agreement between both of them is found to be satisfactory. [less ▲]

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See detailModes d'Organisation et Distribution de l'eau: Une Evaluation empirique de la Performance par les Méthodes des frontières de production
Mande Buafua, Patrick ULg

Doctoral thesis (2014)

Cette thèse est une contribution à l’analyse empirique de la performance (efficacité technique et effectivité) dans le secteur de la distribution de l’eau en Afrique Subsaharienne. Nous cherchons à ... [more ▼]

Cette thèse est une contribution à l’analyse empirique de la performance (efficacité technique et effectivité) dans le secteur de la distribution de l’eau en Afrique Subsaharienne. Nous cherchons à répondre à la question de l’impact des modes d’organisation (participation du secteur privé, régulation et une combinaison de deux) sur l’amélioration de la performance dans ce secteur. Notre analyse s’appuie sur les données issues de la base des données de l’AICD pour la période 2000 à 2005. Premièrement, grâce au modèle de Battese & Coelli (1995), nous calculons les scores d’efficacité technique et nous identifions les sources de l’inefficacité technique. L’approche PLP nous sert de technique complémentaire pour approfondir l’examen des élasticités d’échelle et du coût implicite des pertes d’eau sur le réseau pour chaque opérateur. En moyenne, les entreprises de l’échantillon sont techniquement inefficaces sur la période. Réguler par contrat de performance conduit à des scores d’efficacité technique plus élevés que réguler par agence. La participation du secteur privé dans la gestion ou l’exploitation du service présente un effet positif sur l’efficacité technique. Il n’y a pas de preuve d’une différence significative entre l’efficacité technique des entreprises sous gestion publique régulées par contrat de performance ou par agence de régulation et celles avec participation du secteur privé dans la gestion ou l’exploitation régulées par contrat de performance ou par agence de régulation. Les élasticités d’échelle sont, en moyenne, décroissantes. Le coût des pertes d’eau sur le réseau est évalué, en moyenne, à 4 travailleurs pour 100.000 m³ d’eau perdue. De plus, ce coût marginal a tendance à augmenter avec les niveaux de la qualité du réseau. Deuxièmement, nous analysons notre question de recherche en prenant en compte la performance en termes d’effectivité. Nous nous appuyons sur la méthode DEA basée sur la procédure en double bootstrap (Simar & Wilson, 2007) en appliquant l’approche analytique, en 4 étapes, inspirée de Mbuvi et al., (2012). Les résultats laissent entrevoir l’existence d’un problème d’ineffectivité plus élevé que celui d’inefficacité technique. Ainsi, les opérateurs ont besoin des ressources additionnelles pour atteindre 100% de leur effectivité. Réguler par contrat de performance conduit à une plus grande effectivité que réguler par agence de régulation. La variable relative à la participation du secteur privé dans la gestion ou l’exploitation du service a un effet négatif et significatif sur l’effectivité. Enfin, il n’y a pas de différence significative, en termes d’effectivité, entre les entreprises avec participation du secteur privé dans la gestion ou l’exploitation régulées par agence ou par contrat de performance et celles publiques régulées par agence ou par contrat de performance. Enfin, nous évaluons l’impact des variables institutionnelles sur les taux de couverture du service en utilisant les modèles à effets fixes. Nous nous attaquons à la question de l’endogénéité en utilisant le cadre proposé par Heckman (1978). Réguler par contrat de performance a un effet positif et significatif sur les taux de couverture. La participation du secteur privé dans la gestion ou l’exploitation du service possède un effet négatif et significatif sur les taux de couverture du service. Combiner la gestion publique avec la régulation par agence ou par contrat de performance conduit à des taux de couverture du service plus élevés que combiner la participation du secteur privé dans la gestion ou l’exploitation du service avec la régulation par agence ou par contrat de performance. [less ▲]

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See detailHOLOCENE DUST RECORD IN A BELGIAN PEAT BOG: MULTIPROXY GEOCHEMICAL APPROACH
Allan, Mouhamd ULg; gael, le roux; Fagel, Nathalie ULg et al

in dust 2014, Book of ABSTRACTS, International Conference on ATMOSPHERIC DUST (2014, June 01)

Ombrotrophic peatlands are unique environmental archives of natural and anthropogenic atmospheric dust deposition. Their surface layers are exclusively fed by atmospheric inputs. A peat bog core from ... [more ▼]

Ombrotrophic peatlands are unique environmental archives of natural and anthropogenic atmospheric dust deposition. Their surface layers are exclusively fed by atmospheric inputs. A peat bog core from Misten in Eastern Belgium southern covering the last 7500 years (dated by 210Pb and 14C methods) was investigated to reconstruct dust depostion based on a combination of the Rare Earth Elements (REE) and lithogenic elements concentrations, as well as Nd and Pb isotopes data. Nd isotope signature was used to decipher between local and distal dust supplies, the Pb isotopes to trace the antropogenic influences. Peat humification was used to evaluate hydroclimatic conditions. Dust fluxes show pronounced increase at 3200-2800BC, 600BC, AD600, 1000AD, 1200AD and from 1700 AD. Lead isotope signatures are consistent with local and regional contamination by coal combustion and smelting activities. The Nd values show large variability, between -5 and –13, identifying three major sources of dust: local soils, distal volcanic and desert particles. Our results are in agreement with atmospheric reconstructions from other continental archives, confirming that the Misten peat is a valid archive for dust deposition. The approach combining geochemical elementary content and isotope data in ombrotrophic peat allows to decipher between dust flux changes related to human and climate forcing. [less ▲]

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See detailThe four duties of family doctors. Quaternary prevention: First, do no harm
Jamoulle, Marc ULg

in Hong Kong Practitioner (2014), 36

Cl inical prevent ion has been organised in a chronological manner since the middle of the 20th century. A paradigm shift from a chronological to a relationship-based preventive pattern of care offers new ... [more ▼]

Cl inical prevent ion has been organised in a chronological manner since the middle of the 20th century. A paradigm shift from a chronological to a relationship-based preventive pattern of care offers new insight into the practice of doctors, and brings to light the concept of quaternary prevention, a critical look at medical activities with an emphasis on the need not to harm. Quaternary prevention addresses the fundamental question of what constitutes too much or too little medicine. It is the fourth form of disease prevention, but also the fourth frame of action for family doctors. New definitions of prevention published in the Wonca Dictionary of Family Medicine offer a structured way to discuss the activities of family doctors, including ethical considerations on the patient-doctor encounter. 摘要 [less ▲]

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See detailPhase resolved X-ray spectroscopy of HDE 288766: Probing the wind of an extreme Of+/WNLha star
Rauw, Grégor ULg; Mahy, Laurent; Nazé, Yaël ULg et al

in Astronomy and Astrophysics (2014), 566

Context. HDE 228766 is a very massive binary system hosting a secondary component, which is probably in an intermediate evolutionary stage between an Of supergiant and an WN star. The wind of this star ... [more ▼]

Context. HDE 228766 is a very massive binary system hosting a secondary component, which is probably in an intermediate evolutionary stage between an Of supergiant and an WN star. The wind of this star collides with the wind of its O8 II companion, leading to relatively strong X-ray emission. <BR /> Aims: Measuring the orbital variations of the line-of-sight absorption toward the X-ray emission from the wind-wind interaction zone yields information on the wind densities of both stars. <BR /> Methods: X-ray spectra have been collected at three key orbital phases to probe the winds of both stars. Optical photometry has been gathered to set constraints on the orbital inclination of the system. <BR /> Results: The X-ray spectra reveal prominent variations of the intervening column density toward the X-ray emission zone, which are in line with the expectations for a wind-wind collision. We use a toy model to set constraints on the stellar wind parameters by attempting to reproduce the observed variations of the relative fluxes and wind optical depths at 1 keV. <BR /> Conclusions: The lack of strong optical eclipses sets an upper limit of ~ 68° on the orbital inclination. The analysis of the variations of the X-ray spectra suggests an inclination in the range 54-61° and indicates that the secondary wind momentum ratio exceeds that of the primary by at least a factor 5. Our models further suggest that the bulk of the X-ray emission arises from the innermost region of the wind interaction zone, which is from a region whose outer radius, as measured from the secondary star, lies between 0.5 and 1.5 times the orbital separation. Based on observations collected with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA member states and the USA (NASA), and on data collected at the San Pedro Mártir observatory (Mexico). [less ▲]

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See detailComputational homogenization of cellular materials
Nguyen, Van Dung ULg; Noels, Ludovic ULg

in International Journal of Solids and Structures (2014), 51(11-12), 2183-2203

In this work we propose to study the behavior of cellular materials using a second–order multi–scale computational homogenization approach. During the macroscopic loading, micro-buckling of thin ... [more ▼]

In this work we propose to study the behavior of cellular materials using a second–order multi–scale computational homogenization approach. During the macroscopic loading, micro-buckling of thin components, such as cell walls or cell struts, can occur. Even if the behavior of the materials of which the micro–structure is made remains elliptic, the homogenized behavior can lose its ellipticity. In that case, a localization band is formed and propagates at the macro–scale. When the localization occurs, the assumption of local action in the standard approach, for which the stress state on a material point depends only on the strain state at that point, is no–longer suitable, which motivates the use of the second-order multi–scale computational homogenization scheme. At the macro–scale of this scheme, the discontinuous Galerkin method is chosen to solve the Mindlin strain gradient continuum. At the microscopic scale, the classical finite element resolutions of representative volume elements are considered. Since the meshes generated from cellular materials exhibit voids on the boundaries and are not conforming in general, the periodic boundary conditions are reformulated and are enforced by a polynomial interpolation method. With the presence of instability phenomena at both scales, the arc–length path following technique is adopted to solve both macroscopic and microscopic problems. [less ▲]

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See detailArrival of european eel in Belgian Part of the Meuse: who and how are they?
Nzau Matondo, Billy ULg; Benitez, Jean-Philippe ULg; Dierckx, Arnaud ULg et al

in Proceedings of the 10th International Conference on Ecohydraulics (2014, June)

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See detailLe Portrait photographique d'écrivain
Bertrand, Jean-Pierre ULg; Durand, Pascal ULg; Lavaud, Martine

in COnTEXTES : Revue de Sociologie de la Littérature (2014), 14

Il en va des phénomènes omniprésents comme des évidences : ils passent volontiers inaperçus quand ils ne sont pas reçus comme procédant d’une nature des choses plutôt que d’une émergence historique et ... [more ▼]

Il en va des phénomènes omniprésents comme des évidences : ils passent volontiers inaperçus quand ils ne sont pas reçus comme procédant d’une nature des choses plutôt que d’une émergence historique et sociale. Vitrines de libraires, quatrièmes de couverture, affiches publicitaires, catalogues d’éditeur, manuels scolaires, monographies illustrées, journaux, magazines, émissions de télévision, documentaires, vidéos continuent d’enfoncer jour après jour dans notre œil l’évidence aveuglante que l’écrivain a un visage. Il n’en a pas toujours été ainsi et c’est bien en s’en avisant que l’on peut se mettre en condition de prendre la mesure des effets que la photographie, après d’autres formes de représentation iconographique, puis en concurrence avec celles-ci, a exercés non seulement sur la mise en image de la littérature et la visibilité de ceux qui la produisent, mais encore sur leur commune définition sociale après 1840. C’est dans cet esprit général, sensible aux modalités matérielles de l’histoire des représentations ainsi qu’aux implications épistémologiques du portrait photographique d’écrivain, que s’inscrivent les contributions réunies à l’enseigne de la revue Contextes. Elles proviennent de deux journées d’études qui se sont tenues à l’Université de Liège les 6 et 7 juin 2013 en vue d’éclairer sous différents aspects l’histoire des formes, des supports et des usages du portrait photographique d’écrivain de la fin des années 1830 à l’époque contemporaine — du romantisme au Nouveau Roman ou encore de Balzac à Houellebecq. Conformément à l’objet étudié, l’approche développée se veut résolument transdisciplinaire. Historiens de l’art et de la photographie rappellent utilement les conditions de naissance et de développement exponentiel d’un genre ayant bousculé l’ordre des représentations et les esthétiques. Historiens et sociologues de la littérature font ressortir les liens établis entre portrait photographique et auteurs photographiés, avec les implications que le médium a occasionnées durablement dans l’imaginaire littéraire. Sémioticiens et spécialistes des sciences du langage mettent en œuvre leur outillage descriptif sur la matérialité et la discursivité du cliché. Avec cela de commun en ligne de mire : à quoi tient la littérarité d’un portrait photographique d’écrivain ? A cette question, le dossier apporte quelques éléments de réponse en proposant un recadrage et un décadrage. Recadrage de l’image elle-même au sein des configurations auxquelles elle participe. Décadrage du portrait en direction des effets de contexte et de support qui sont inducteurs de sa signification. SOMMAIRE Martine LAVAUD (Paris IV), « Envisager l’histoire littéraire. Pour une épistémologie du portrait photographique d’écrivain » Pascal DURAND (ULg), « De Nadar à Dornac. Hexis corporelle et figuration photographique des écrivains » Jean-Pierre BERTRAND (ULg), « Esquisse d’un protocole de lecture du portrait photographique d’écrivain » Marc-Emmanuel MÉLON (ULg), Portrait de l’écrivain absorbé. Une allégorie photographique » Adeline WRONA (Celsa, Université Paris Sorbonne), « Le portrait-carte, de la photographie au journal. Le marché périodique du portrait d’écrivain » Hélène VÉDRINE (Université Paris Sorbonne), « Portraits de masques et de fantômes. Le portrait photographique dans le livre (1860-1930) » Bernard VOUILLOUX (Université Paris Sorbonne), « Une collection d’unica : les livres à portraits d’Edmond de Goncourt » François PROVENZANO (ULg), « Portrait photographique d’écrivain et newsmagazine. Pour une approche rhétorique de l’événementialité du littéraire » Fanny LORENT (ULg), « Portrait et imaginaire photographique. Cliché et anti-cliché du Nouveau Roman » Maria Giulia DONDERO (FNRS/ULg), « Les approches sémiotiques du portrait photographique. De l’identité à l’“air” » Jérôme MEIZOZ (Université de Lausanne), « Portrait photographique et présentation de soi. Cendrars, Houellebecq » [less ▲]

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See detailOn the Quality of BGP Route Collectors for iBGP Policy Inference
Cittadini, Luca; Vissicchio, Stefano; Donnet, Benoît ULg

in IFIP Networking (2014, June)

A significant portion of what is known about Internet routing stems out from public BGP datasets. For this reason, numerous research efforts were devoted to (i) assessing the (in)completeness of the ... [more ▼]

A significant portion of what is known about Internet routing stems out from public BGP datasets. For this reason, numerous research efforts were devoted to (i) assessing the (in)completeness of the datasets, (ii) identifying biases in the dataset, and (iii) augmenting data quality by optimally placing new collectors. However, those studies focused on techniques to extract information about the AS-level Internet topology. In this paper, we show that considering different metrics influences the conclusions about biases and collector placement. Namely, we compare AS-level topology discovery with \iac inference. We find that the same datasets exhibit significantly diverse biases for these two metrics. For example, the sensitivity to the number and position of collectors is noticeably different. Moreover, for both metrics, the marginal utility of adding a new collector is strongly localized with respect to the proximity of the collector. Our results suggest that the ``optimal'' position for new collectors can only be defined with respect to a specific metric, hence posing a fundamental trade-off for maximizing the utility of extensions to the BGP data collection infrastructure. [less ▲]

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