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See detailAn Alternative to Semantics?
Gauvry, Charlotte ULg

Conference (2015, February 12)

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See detailVolatile Organic Chemicals in the Rhizosphere of Barley, and their Role on the Foraging Behavior of Wireworms (Coleoptera: Elateridae)
Barsics, Fanny ULg

Doctoral thesis (2015)

Many species of wireworms, the larvae of click beetles (Coleoptera: Elateridae), are known as worldwide belowground pests of a large range of crops including cereals. Pesticide based agricultural ... [more ▼]

Many species of wireworms, the larvae of click beetles (Coleoptera: Elateridae), are known as worldwide belowground pests of a large range of crops including cereals. Pesticide based agricultural practices seem to have allowed significant population reduction in the past, but there is an increasing need for alternative control methods. In the first Chapter of this work, we review the current knowledge concerning 1) Integrated Pest Management (IPM) of wireworms and 2) their chemical ecology. These reviews shed light on promising approaches to develop new management strategies, as well as gaps of knowledge to be filled in that purpose. One of them is investigated here. The research aim of this PhD thesis (detailed in Chapter II) is the identification of the volatile organic compounds (VOC) released by the roots and used by wireworms to locate their food source. To achieve this goal, we defined three objectives: 1) developing a behavioral assay suitable for the study of wireworm orientation behavior under exposure to root-produced VOC; 2) profiling VOC released in the rhizosphere, according to different growth conditions; and 3) evaluating the role of the identified VOC on wireworm foraging behavior. Our experimental model involved Agriotes sordidus Illiger wireworms and Hordeum distichon L. (spring barley). In Chapter III, we report on the developmental steps of an adequate olfactometric method for wireworms. This includes an initial setup, the “Y-shaped” olfactometer, and dual-choice pipes gathering the necessary upgrades to efficiently observe the behavior of wireworms exposed to a VOC source. By resorting to live roots in a variety of features, we attempted to highlight appropriate abiotic and biotic experimental parameters, as well as the limits to the use of our olfactometric devices. The bioassays confirmed the attraction of wireworms towards VOC emitted by live roots. With a first sampling method on excised roots, Solid – Phase Micro – Extraction (SPME – semi-quantitative), coupled to Gas Chromatography – Mass Spectrometry (GC-MS), we detected a high number of molecules that might act as semiochemicals on wireworms, notably in our bioassays. In the fourth Chapter, the bioassays were performed with selected VOC, detected during the chemical profiling. Firstly, we assessed if wireworms were attracted towards 2 pentylfuran, the main VOC highlighted with SPME. The molecule was submitted to the larvae by encapsulation in alginate beads. An adequate formulation allowed reaching an emission rate matching quantification estimates. In the aim to improve the VOC profiling, we also used Dynamic Head-Space Sampling (DHS), on roots ground in liquid nitrogen. It highlighted four volatile aldehydes. Their biological activity on wireworms was evaluated thanks to glass wool/triacetin-based dispensers, inserted in the dual-choice pipes. Through this work, we show that VOC produced by barley roots carry information useable by foraging wireworms. The two sampling methods indicate two different modalities of root-VOC production and are encouraging for further understanding of belowground VOC production and emission. The developed olfactometric method and related results open new perspectives to increase knowledge on wireworm ecology. Combined to other developments in research on their management, they could lead to interesting, innovative and ecological management practices. [less ▲]

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See detailPourquoi certaines réparations échouent-elles ? Un problème de compatibilité !
Courard, Luc ULg

Scientific conference (2015, February 12)

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See detailEnvironmental / climatic changes & the people ...
Ozer, Pierre ULg

Scientific conference (2015, February 11)

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See detailCognitive remediation of autobiographical memory in schizophrenia and its relation with depressive mood.
Blairy, Sylvie ULg

Scientific conference (2015, February 09)

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See detailQuestion d'actualité en environnement : un cours intégrateur/ transversal qui fait sens pour les étudiants de Bac1 en sciences Bio-ingénieur
Colaux, Catherine ULg

Conference given outside the academic context (2015)

Lors de son entrée à l'université l'étudiant primant est souvent décontenancé. Tous les changements auxquels il doit faire face (organisation des cours, exigences des enseignants, nouveau contexte social ... [more ▼]

Lors de son entrée à l'université l'étudiant primant est souvent décontenancé. Tous les changements auxquels il doit faire face (organisation des cours, exigences des enseignants, nouveau contexte social etc.) le conduisent quelques fois à douter, allant même quelques fois jusqu'à remettre en question son choix d'orientation. Les étudiants Bioingénieurs de Gembloux Agro Bio Tech ne dérogent pas à cette règle. Il nous paraissait donc primordial de proposer à l'horaire de première année un cours intégrateur qui puisse conforter les étudiants dans leur choix de filière mais plus encore, qui puisse impacter leur perception de valeur, souvent négative, de certains de leurs enseignements. Un des objectifs de ce cours est donc de démontrer à nos étudiants, en traitant un sujet d'actualité en environnement que leurs cours de mathématique, physique, chimie etc. sont nécessaires à leur formation de bioingénieurs. Ce cours se veut également innovant puisqu'il sortira du canevas ex-cathedra classiquement appliqué en première année et proposera aux étudiants un travail en petits groupes et essentiellement en ligne. Ce sera l'occasion d'aborder avec eux en tout début de cursus ces compétences transversales qui prennent de plus en plus de place dans nos formations. [less ▲]

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See detailCritique des données statistiques 'macro' disponibles dans les institutions internationales
Ozer, Pierre ULg

Scientific conference (2015, February 09)

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See detailImaging the mechanisms involved in abdominal aortic aneurysms rupture; a step towards patient-specific risk assessment
NCHIMI LONGANG, Alain ULg

Doctoral thesis (2015)

Introduction The general context of this dissertation is to evaluate patient-specifi c approaches to the risk of rupture of abdominal aortic aneurysm (AAA), using imaging techniques with ability to assess ... [more ▼]

Introduction The general context of this dissertation is to evaluate patient-specifi c approaches to the risk of rupture of abdominal aortic aneurysm (AAA), using imaging techniques with ability to assess biological processes. Following a thorough description of available imaging techniques, our work is divided in two main research objectives, namely: (i) to provide greater clinical value to existing but unproven imaging concepts, and (ii) to suggest new concepts for improved AAA risk of rupture assessment. Methods The fi rst research objective evaluated how far imaging biological activities using 18F-Fluorodeoxyglucose (FDG) Positron Emission Tomography (PET) and modeling wall stress using fi nite element simulations (FES) may help clinical decisionmaking in patients with AAA, and what would be their incremental value as compared to diameter-based patient management algorithms. On a patient basis, clinical outcomes were evaluated with regard to FDG PET and FES signaling. Further, the concept of AAA risk-equivalent diameter using FES was described and retrospectively validated using data from large multicenter trials. The second research objective included the assessment of the biological activities of the intraluminal thrombus (ILT) and the demonstration of its deleterious role in AAA using multimodality imaging. A special emphasis was put on the ability of magnetic resonance imaging (MRI) to monitor the biological activities of ILT without exogenous contrast, by evaluating its iron content. Results Increased FDG uptake was a diameter-independent marker of AAA-related events over 2 years. Missing dichotomy prevented such a fi nding for increased wall stress, although its correlation with increased FDG uptake indicates a potentially comparable value in terms of risk management. Wall metabolism is infl uenced by patient-specifi c susceptibility factors, indicating hereditary or acquired alteration of the biological responses to wall stress. The concept of risk-equivalent diameters on FES links biomechanical estimates to basic conclusions drawn from large diameter-based clinical AAA trials. Our retrospective and diameter-adjusted validation analysis verifi ed that biomechanical risk indicators are higher in ruptured than non-ruptured AAAs. Part of the FDG uptake is associated with biological activity along the luminal surface of the ILT, where we experimentally demonstrated phagocytosis of superparamagnetic iron oxide on MRI , both ex vivo and in vivo. This phagocytosis is correlated with the abundance of leukocytes and proteolytic activity. In addition, unenhanced MRI appearances resulting from the endogenous iron distribution within ILT also relate to these biological activities. Lastly, multimodality imaging was used to confi rm the concept of the deleterious role of the ILT in AAA growth in a model of AAA by infusion of elastase in the rat. Conclusion MRI and FDG PET are capable of evidencing and quantifying in vivo some of the notoriously deleterious biological processes taking place in the aneurysmal sac, especially related to the entrapped phagocytes and red blood cells in ILT and the periadventitial infl ammatory response. The central role played by ILT and its biological activities was demonstrated in vivo using several imaging techniques. The clinical value of imaging these biological activities is epitomized by a diameterindependent 2-year increased risk of event in AAA with increased wall metabolism. [less ▲]

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See detailZones humides : entre modifications environnementales et actions humaines
Ozer, Pierre ULg

Conference (2015, February 08)

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See detailQuand science politique et droit dialoguent : quelle typologie des instruments mémoriels en fonction du degré de contrainte ?
Grandjean, Geoffrey ULg

Conference (2015, February 07)

Envisager les études sur la mémoire comme sous-champ de la science politique francophone ouvre des pistes enrichissantes pour les politologues, notamment lorsqu’ils sont amenés à analyser les instruments ... [more ▼]

Envisager les études sur la mémoire comme sous-champ de la science politique francophone ouvre des pistes enrichissantes pour les politologues, notamment lorsqu’ils sont amenés à analyser les instruments mémoriels régissant un ou plusieurs système(s) politique(s). Dans cette perspective, la communication vise à présenter, d’un point de vue épistémologique, les apports découlant de l’interaction entre les sciences politique et juridique dans le processus de consolidation des études sur la mémoire comme sous-champ disciplinaire de la science politique. Plus précisément, la communication vise à offrir une typologie des instruments mémoriels en fonction du degré de contrainte et d’imposition d’une mémoire officielle. Par exemple, une résolution adoptée par une assemblée législative est faiblement contraignante alors qu’une loi réprimant le négationnisme impose à la fois une mémoire officielle tout en sanctionnant pénalement les citoyens qui ne la respectent pas. La typologie passe en revue les multiples instruments mémoriels pouvant être adoptés par les autorités publiques : résolution, loi déclarative, loi pénale, plan de commémorations ou encore mise en valeur d’un lieu de mémoire. L’accent est mis sur les instruments mémoriels de deux pays francophones : la Belgique et la France. Au final, cette communication permet d’insister sur l’apport de la science politique en analysant l’exercice de prérogatives de puissance publique et sur l’apport de la science juridique en classifiant les types d’instruments mémoriels en fonction du degré de contrainte ; tout en faisant dialoguer des cas d’étude différents. [less ▲]

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See detailRevisiting the SN1987A gamma-ray limit on ultralight axion-like particles
Payez, Alexandre ULg; Evoli, Carmelo; Fischer, Tobias et al

in Journal of Cosmology and Astroparticle Physics [= JCAP] (2015), 2015(02), 006

We revise the bound from the supernova SN1987A on the coupling of ultralight axion-like particles (ALPs) to photons. In a core-collapse supernova, ALPs would be emitted via the Primakoff process, and ... [more ▼]

We revise the bound from the supernova SN1987A on the coupling of ultralight axion-like particles (ALPs) to photons. In a core-collapse supernova, ALPs would be emitted via the Primakoff process, and eventually convert into gamma rays in the magnetic field of the Milky Way. The lack of a gamma-ray signal in the GRS instrument of the SMM satellite in coincidence with the observation of the neutrinos emitted from SN1987A therefore provides a strong bound on their coupling to photons. Due to the large uncertainty associated with the current bound, we revise this argument, based on state-of-the-art physical inputs both for the supernova models and for the Milky-Way magnetic field. Furthermore, we provide major amendments, such as the consistent treatment of nucleon-degeneracy effects and of the reduction of the nuclear masses in the hot and dense nuclear medium of the supernova. With these improvements, we obtain a new upper limit on the photon-ALP coupling: g_{a\gamma} < 5.3 x 10^{-12} GeV^{-1}, for m_a < 4.4 x 10^{-10} eV, and we also give its dependence at larger ALP masses. Moreover, we discuss how much the Fermi-LAT satellite experiment could improve this bound, should a close-enough supernova explode in the near future. [less ▲]

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See detailSingle Wavelength Coarse Phasing In Segmented Telescopes
Simar, Juan Felipe ULg

in Applied Optics (2015), 54

Space observations of fainter and more distant astronomical objects constantly require telescope primary mirrors with a larger size. The diameter of monolithic primary mirrors is limited to 10 m because ... [more ▼]

Space observations of fainter and more distant astronomical objects constantly require telescope primary mirrors with a larger size. The diameter of monolithic primary mirrors is limited to 10 m because of manufacturing limitations. For space telescopes, the primary mirrors are limited to less than 5 m due to fairing capacity. Segmented primary mirrors thus constitute an alternative solution to deal with the steadily increase of the primary mirror size. The optical path di erence between the individual segments must be close to zero (few nm) in order to be di raction limited. We propose in this paper a new inter-segment piston sensor based on coherence measurement of a star image. This sensor is intended to be used in the co-phasing system of future segmented mirrors. [less ▲]

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See detailA mixed integer nonlinear programming bi-objective model for intermodal network design
Mostert, Martine ULg; Caris, An; Limbourg, Sabine ULg

Conference (2015, February 05)

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See detailQuaternary prevention, an answer of family doctors to overmedicalization
Jamoulle, Marc ULg

in International Journal of Health Policy and Management (2015), 4((X)), 1-4

In response to the questioning of Health Policy and Management (HPAM) by colleagues on the role of rank and file family physicians in the same journal, the author, a family physician in Belgium, is trying ... [more ▼]

In response to the questioning of Health Policy and Management (HPAM) by colleagues on the role of rank and file family physicians in the same journal, the author, a family physician in Belgium, is trying to highlight the complexity and depth of the work of his colleagues and their contribution to the understanding of the organization and economy of healthcare. It addresses, in particular, the management of health elements throughout the ongoing relationship of the family doctor with his/her patients. It shows how the three dimensions of prevention, clearly included in the daily work, are complemented with the fourth dimension, quaternary prevention or prevention of medicine itself, whose understanding could help to control the economic and human costs of healthcare [less ▲]

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See detailSuppression of Limit Cycle Oscillations using the Nonlinear Tuned Vibration Absorber
Habib, Giuseppe ULg; Kerschen, Gaëtan ULg

in Proceeding IMAC XXXIII A Conference and Exposition on Structural Dynamics, Orlando 2-5 February 2015 (2015, February 03)

The objective of the present study is to mitigate, or even completely eliminate, the limit cycle oscillations in mechanical systems using a passive nonlinear absorber, termed the nonlinear tuned vibration ... [more ▼]

The objective of the present study is to mitigate, or even completely eliminate, the limit cycle oscillations in mechanical systems using a passive nonlinear absorber, termed the nonlinear tuned vibration absorber (NLTVA). An unconventional aspect of the NLTVA is that the mathematical form of its restoring force is not imposed a priori, as it is the case for most existing nonlinear absorbers. The NLTVA parameters are determined analytically using stability and bifurcation analyses, and the resulting design is validated numerically using the MATCONT software. The proposed developments are illustrated using a Van der Pol-Du ng primary system. [less ▲]

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See detailContribution to the Macrophytic Typology of Belgian Reference Watercourses
Galoux, Daniel; Cherot, Frédéric; Rosillon, Francis ULg et al

in Advances in Botany (2015), Volume 2015, Article ID 651369

The objective of the study is to create a typology of macrophytes for the reference watercourses of the Meuse River catchment ... [more ▼]

The objective of the study is to create a typology of macrophytes for the reference watercourses of the Meuse River catchment basininWalloniaasasteptowardstheimplementationoftheEuropeanWaterFrameworkDirective.The50sitesstudiedarethe objectofaphysicochemicalandenvironmentalcharacterizationfollowedbyafloristicsurvey(phanerogams,mosses,liverworts, andmacroalgae).Sixclustersofwatercourseswiththeircharacteristicspeciesarehighlightedbytwo-wayclusteringandindicator species. The abundance of phanerogams in some watercourses of the Arden region is not only linked to light intensity but also dependsonthedegreeofslopeandthenatureofthegeologicalsubstrate [less ▲]

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See detailEconomics of a decision-support system for managing the main fungal diseases of winter wheat in the Grand-Duchy of Luxembourg
El Jarroudi, Moussa ULg; Kouadio, Louis; Beyer, Marco et al

in Field Crops Research (2015), 172(2), 32-41

We evaluated the cost effectiveness of a decision-support system (DSS) developed for assessing in real time the risk of progression of the main fungal diseases (i.e., Septoria leaf blotch, powdery mildew ... [more ▼]

We evaluated the cost effectiveness of a decision-support system (DSS) developed for assessing in real time the risk of progression of the main fungal diseases (i.e., Septoria leaf blotch, powdery mildew, leaf rusts and Fusarium head blight) of winter wheat in the Grand-Duchy of Luxembourg (GDL). The study was conducted in replicated field experiments located in four agricultural locations (representative of the main agro-ecological regions of the country) over a 10-year period (2003-2012). Three fungicide spray strategies were compared: a single DSS-based system and two commonly used spray practices in the GDL, a double- (2T)- and a triple- spray (3T) spray treatment; there was also a non-treated control. In years with a high disease pressure, the DSS-based recommendation resulted in protection of the three upper leaves comparable to that achieved with the 2T and 3T treatments, with significant grain yield increases (P > 0.05) compared to the control (a 4 to 42% increase, depending on the site and year). Overall, the financial gain in treated plots compared with the control ranged from 3 to 16% at the study sites. Furthermore, in seasons when dry weather conditions precluded epidemic development, no the DSS-basedDSS recommended no fungicide spray was recommended, reducing use of fungicide, and thus saving the cost of the product. The gain in yield for the 2T and 3T plots (compared with control) did not necessarily result in a financial gain during the duration of the experiment. This study demonstrates the potential advantages and profitability of using a DSS -based approach for disease management. [less ▲]

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See detailLes PPP comme nouveau mode de régulation du marché de l'accompagnement des demandeurs d'emploi. A chaque modèle de partenariat son type de stratégie
Remy, Céline ULg

in Cahiers Loyola (2015, February), 1

Cette communication vise à montrer en quoi les partenariats publics-privés (PPP) constituent désormais un nouveau mode de régulation du marché de l’accompagnement des demandeurs d’emploi. Les services ... [more ▼]

Cette communication vise à montrer en quoi les partenariats publics-privés (PPP) constituent désormais un nouveau mode de régulation du marché de l’accompagnement des demandeurs d’emploi. Les services publics de l’emploi (SPE) doivent établir des PPP avec des prestataires de service pour la mise en place de formation à destination des demandeurs d’emploi. La réalisation de trois études de cas au sein des SPE, dont deux en Belgique et une en Suisse, nous permet de mettre en évidence une forte influence du modèle de gestion du PPP sur la collaboration entre les parties-prenantes mais aussi sur les stratégies développées par les prestataires pour surmonter les problèmes liés à la collaboration avec l’Office de l’Emploi et à la mise en place de la prestation de service. [less ▲]

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See detailEffects of low dose endosulfan exposure on brain neurotransmitter levels in the African clawed frog Xenopus laevis
Preud'Homme, Valérie; Milla, Sylvain; Gillardin, Virginie et al

in Chemosphere (2015), 120(2), 357-364

Understanding the impact of pesticides in amphibians is of growing concern to assess the causes of their decline. Among pesticides, endosulfan belongs to one of the potential sources of danger because of ... [more ▼]

Understanding the impact of pesticides in amphibians is of growing concern to assess the causes of their decline. Among pesticides, endosulfan belongs to one of the potential sources of danger because of its wide use and known effects, particularly neurotoxic, on a variety of organisms. However, the effect of endosulfan was not yet evaluated on amphibians at levels encompassing simultaneously brain neurotransmitters and behavioural endpoints. In this context, tadpoles of the African clawed frog Xenopus laevis were submitted to four treatments during 27 d: one control, one ethanol control, and two low environmental concentrations of endosulfan (0.1 and 1 μg L−1). Endosulfan induced a significant increase of brain serotonin level at both concentrations and a significant increase of brain dopamine and GABA levels at the lower exposure but acetylcholinesterase activity was not modified by the treatment. The gene coding for the GABA transporter 1 was up-regulated in endosulfan contaminated tadpoles while the expression of other genes coding for the neurotransmitter receptors or for the enzymes involved in their metabolic pathways was not significantly modified by endosulfan exposure. Endosulfan also affected foraging, and locomotion in links with the results of the physiological assays, but no effects were seen on growth. These results show that low environmental concentrations of endosulfan can induce adverse responses in X. laevis tadpoles. At a broader perspective, this suggests that more research using and linking multiple markers should be used to understand the complex mode of action of pollutants. [less ▲]

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