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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 detailDevelopment of Hyphenated Methods for the Comprehensive Analysis of Complex Biological Samples
Brasseur, Catherine ULg

Doctoral thesis (2015)

The successful analysis of complex mixtures requires the combination of highly efficient separation techniques with advanced detection technologies to provide individual structural information. The ... [more ▼]

The successful analysis of complex mixtures requires the combination of highly efficient separation techniques with advanced detection technologies to provide individual structural information. The coupling of gas chromatography and mass spectrometry was one of the first steps in hyphenated method development. Nowadays, due to continuous hardware improvement, the term hyphenation has been extended to multidimensional separations and/or multiple detectors. The objective of the thesis is to develop hyphenated methods to extend the range of applications and propose solutions to improve the characterization of specifically selected complex samples. The main hyphenated technique that was used is comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC×GC-TOFMS). Three thematic areas, presenting different levels and types of complexity were investigated: Forensic geotaphonomy with grave soil samples, lignocellulose biomass valorization with termite gut microbiota samples, and human monitoring for emerging organohalogen contaminants with blood samples. Data processing strategies were also developed in order to extract the relevant information from the large quantities of data produced. The different strategies included retention time alignment, comparative data processing, multivariate analysis using unsupervised learning algorithm such as principal component analysis (PCA), univariate analysis of variance (one-way ANOVA), and scripting for automated filtering of mass spectra. All developed methods allowed to successfully improve the characterization of samples originating from the different areas. For the first time, and because of the high level of specificity of GC×GC-TOFMS, the presence of methyl-branched alkane compounds was highlighted in grave soil samples, allowing to develop a screening method that has the capacity to differentiate between soils at proximity of buried decaying pig carcasses and control soils. This strategy could complement other approaches and contribute to aid forensic geotaphonomy investigators. In the biomass valorization area, more than 300 compounds were isolated and partly identified in the 1µL fluid volume available from the termite gut. A comparative study demonstrated that the adaptation of the termite system to non-optimal carbon sources is reflected in the metabolite profile. These results demonstrated the potential interest to investigate metabolite profiling with state-of-the-art separation science tools, to contribute to a better understanding of how termites efficiently degrades lignocellulose. In the human monitoring area, the analysis of serum samples using GC×GC-TOFMS and scripting allowed the efficient reduction of the data matrix from thousands of detected signals to a few important dozens, including the environmental contaminants of interest present in human blood plasma. Such an approach reduced data processing and reviewing time by several orders of magnitude while maintaining a high degree of identification power. This exploratory approach could result in the identification of emerging toxicants and help regulation bodies to gather better information before they rule on emerging issues. GC with high resolution mass spectrometry (HRMS) was also used, using a selective approach to evaluate human exposure to dechloranes, a family of emerging halogenated flame retardants recently reported as significantly present in the environment. A comprehensive approach was also developed using GC×GC coupled to high resolution TOFMS (HRTOFMS). The developed methodology will facilitate the monitoring of these emerging dechlorane contaminants and analogues in future exploratory studies. [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 detailEncourager un vieillissement cognitif sain par un travail adapté (work shop)
Grotz, Catherine ULg; Adam, Stéphane ULg

Conference (2015, February 12)

L'objectif du workshop est d'apporter des éléments pratiques/cliniques en faveur d'un vieillissement cognitif de qualité, y compris une discussion des mesures à mettre en place en ce qui concerne l ... [more ▼]

L'objectif du workshop est d'apporter des éléments pratiques/cliniques en faveur d'un vieillissement cognitif de qualité, y compris une discussion des mesures à mettre en place en ce qui concerne l'employabilité de la population active plus âgée. [less ▲]

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See detailQuand la clinique bouscule les concepts
Englebert, Jérôme ULg

Scientific conference (2015, February 11)

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See detailRisk of emergence of a hyperpathogenic bovine leukemia virus by mutation of a single envelope N-linked glycosylation site
De Brogniez, Alix ULg; Bouzar, Amel-Baya; Jacques, Jean-Rock ULg et al

Poster (2015, February 11)

- Introduction : Pathogens have co-evolved with their host to ensure efficient replication and transmission without inducing excessive pathogenicity that would indirectly impair their persistence. This is ... [more ▼]

- Introduction : Pathogens have co-evolved with their host to ensure efficient replication and transmission without inducing excessive pathogenicity that would indirectly impair their persistence. This is exemplified by the bovine leukemia virus (BLV) system in which lymphoproliferative disorders develop in ruminants after latency periods of several years. Infection of sheep and cattle with BLV is a model system for the related human T-lymphotropic virus type 1 (HTLV-1) responsible for Adult T-cell Leukemia (ATL). - Aims : The goal of this work is to investigate the role of N-glycans of the viral envelope protein during viral replication and pathogenesis. - Methods and results : Using glycosylation inhibitors and lectins, we showed that N-glycosylation is involved in viral infection (i.e. cell-to-cell fusion). Using reverse genetics of an infectious molecular provirus, we next demonstrated that a particular N-linked envelope glycosylation site (N230) limits viral replication and pathogenicity in vitro and in vivo. We have thus generated a viral mutant that is more pathogenic than the wild type strain. - Conclusions : To our knowledge, this is the first time that a hyperpathogenic BLV has been identified. This unexpected observation has important consequences in terms of disease control and managing. Indeed, during evolution, pathogens and their hosts should achieve an equilibrium allowing the coexistence of the two species. Occurrence of this particular mutation may thus represent a potential threat associated with emergence of hyperpathogenic BLV strains and possibly of new variants of the related HTLV-1. [less ▲]

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

Scientific conference (2015, February 11)

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See detailTen years of Martian nitric oxide nightglow observations
Stiepen, Arnaud ULg; Gérard, Jean-Claude ULg; Gagné, Marie-Eve et al

in Geophysical Research Letters (2015)

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See detailC'est la faute à l'Europe !
Grandjean, Geoffrey ULg

Conference given outside the academic context (2015)

Nombreux sont les dirigeants politiques et les citoyens qui considèrent que l’Union européenne est responsable de la situation politique et économique actuelle. L’exposé vise à interroger ces discours et ... [more ▼]

Nombreux sont les dirigeants politiques et les citoyens qui considèrent que l’Union européenne est responsable de la situation politique et économique actuelle. L’exposé vise à interroger ces discours et à comprendre la place et le rôle des institutions européennes. Il permet surtout de relativiser ces discours en ciblant précisément les marges de manœuvre de l’Union européenne. [less ▲]

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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 detailSome misunderstood or unknown LaTeX tricks (XVI)
Merciadri, Luca ULg

E-print/Working paper (2015)

This is the second (and last) part of the tricks I found on StackExchange. First part began in the preceding issue. We will begin by a personal trick, and end by some inquiry about my LaTeX Tips & Tricks.

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See detailSome misunderstood or unknown LaTeX tricks (XV)
Merciadri, Luca ULg

E-print/Working paper (2015)

After having looked at about 150 StackExchange pages of 50 topics (that sums up to about 7500 topics’ names), I give you, in this article and in the next issue, the most interesting topics’ answers to my ... [more ▼]

After having looked at about 150 StackExchange pages of 50 topics (that sums up to about 7500 topics’ names), I give you, in this article and in the next issue, the most interesting topics’ answers to my eyes. We will first begin by two additions in regard to 31(3), 32(1). [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 detailThe return of Turkey to the Western Balkans: a challenge or an opportunity for the European Union ?
Lika, Liridon ULg

Conference (2015, February 07)

In the new Turkish doctrine, besides the great interests in Central Asia, Middle East, Africa and the Caucasus, the Balkans are also important. Turkey is making great efforts to play a greater role on the ... [more ▼]

In the new Turkish doctrine, besides the great interests in Central Asia, Middle East, Africa and the Caucasus, the Balkans are also important. Turkey is making great efforts to play a greater role on the international scene and creates its area of interest, especially where the links of Ottoman legacy can help. Although it is defined as a peaceful power in the region, some describe it as neo-ottoman, a term rejected by the Turkish authorities because of its possible imperialist connotation. This paper aims precisely to study the return of Turkey to the Balkans. Our central question is: what is the purpose of the Turkish foreign policy in the Western Balkans? Related issues will be addressed such as: is there a competition between Turkey and the European Union in this area? What are the specifics of Turkish foreign policy? In order to explore these research questions, this study focuses on the concept of soft power through which Turkey extends its power. Indeed, the Turkish government imposes itself on the Balkans not by force but with the help of economics, diplomacy, trade, culture and religion. Following the crisis in the EU, causing the collapse of Western investment and a relative decrease of attraction for the Balkans, Turkey has taken advantage of the situation in order to increase its influence in all areas. This contribution will proceed in three stages. Firstly, we will make an analysis of the authors of soft power to think about the character of the new Turkish geopolitical doctrine. Secondly, we are going to apply this theoretical framework to the case study identified, namely the influence of Turkey in the Western Balkan countries. Finally, we will show if exists a competition or a cooperation between Turkey and European Union in the Western Balkans. [less ▲]

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See detailIn situ investigation of scCO2 assisted impregnation of drug into polymer by high pressure FTIR micro-spectroscopy
Champeau, Mathilde ULg; Thomassin, Jean-Michel ULg; Jérôme, Christine ULg et al

in Analyst (2015), 140(3), 869-879

An original experimental set-up combining a FTIR microscope with a high pressure cell has been built in order to analyze in-situ the impregnation of solute into microscopic polymer samples, such as fibers ... [more ▼]

An original experimental set-up combining a FTIR microscope with a high pressure cell has been built in order to analyze in-situ the impregnation of solute into microscopic polymer samples, such as fibers or films, subjected to supercritical CO2. Thanks to this experimental set-up, key factors governing the impregnation process can be simultaneously followed such as the swelling of the polymeric matrix, the CO2 sorption, the kinetic of impregnation and the drug loading into the matrix. Moreover, the solute/polymer interactions and the speciation of the solute can be analyzed. We have monitored in situ the impregnation of aspirin and ketoprofen into PEO (Polyethylene Oxide) platelets at T=40°C and P=5; 10 and 15 MPa. The kinetic of impregnation of aspirin was quicker than the one of ketoprofen and the final drug loading was also higher in case of aspirin. Whereas the CO2 sorption and the PEO swelling remain constant when PEO is just subjected to CO2 under isobaric conditions, we noticed that both parameters can increase while the drug impregnates PEO. Coupling these results with DSC measurements, we underlined the plasticizing effect of the drug that also leads to decrease the crystallinity of PEO in situ thus favoring the sorption of CO2 molecules into the matrix and the swelling of the matrix. The plasticizing effect increases with the drug loading. Finally, the speciation of drug was investigated considering the shift of the carboxyl bands of the drugs. Both drugs were found to be mainly homogeneously dispersed into PEO. [less ▲]

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See detailLa pérennisation des partenariats publics-privés dans le champ de l’emploi : entre application, interprétation et ajustement du cadre réglementaire
Remy, Céline ULg; Gérard, Julie ULg; Beuker, Laura ULg

Conference (2015, February 07)

Dans une perspective de gestion mixte du marché du travail, les services publics de l’emploi sont invités, par la Convention 181 de l’OIT de 1997, à déléguer et à confier l’exploitation et la gestion de ... [more ▼]

Dans une perspective de gestion mixte du marché du travail, les services publics de l’emploi sont invités, par la Convention 181 de l’OIT de 1997, à déléguer et à confier l’exploitation et la gestion de leurs activités à des opérateurs privés de service, dans le cadre d’une entente contractuelle. Alors que les modalités de la collaboration (telles que le public-cible, le type et le nombre d’accompagnements dispensés, les résultats à atteindre, etc.) sont fixées, initialement, par les services publics de l’emploi, elles sont ensuite mises en pratique par les diverses parties-prenantes du partenariat. Les acteurs publics et privés exploitent la part de latitude inhérente à leur fonction pour interpréter et ajuster les termes du contrat ou pour pouvoir réaliser leur mission d’accompagnement des demandeurs d’emploi. Partant du postulat que la règle est incomplète, notre objectif est d’analyser la mise en œuvre du partenariat en saisissant les arguments avancés par les acteurs pour justifier et légitimer leurs actions. À partir de cette analyse, nous montrerons que les acteurs du partenariat doivent interpréter les règles – écart entre le travail prescrit et le travail effectivement presté – dans leurs pratiques quotidiennes. Agissant comme des « pseudo » street-level bureaucrats, ces derniers usent de leur pouvoir pour ajuster les règles. En outre, il semblerait que ces pratiques d'indiscipline permettent, en réalité, de maintenir les relations partenariales entre services publics de l’emploi et opérateurs privés, et d’œuvrer, in fine, à la pérennisation de celles-ci dans le champ de l’emploi. Nous appuierons notre analyse sur un matériau empirique composé d’observations participantes et d’entretiens semi-directifs réalisés auprès des parties-prenantes des PPP, situés en Belgique francophone. [less ▲]

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