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See detailLiens entre le statut socio-économique et la consommation de substances chez les adolescents : Quelles incidences pour les filles et les garçons ?
Mathys, Cécile ULg; Hénin, Tamara; Glowacz, Fabienne ULg

Conference (2014, May)

La consommation de substances à l’adolescence constitue une conduite à risque qui n’en est pas moins populaire chez les jeunes. Ses facteurs explicatifs sont régulièrement examinés, toutefois, les liens ... [more ▼]

La consommation de substances à l’adolescence constitue une conduite à risque qui n’en est pas moins populaire chez les jeunes. Ses facteurs explicatifs sont régulièrement examinés, toutefois, les liens qui unissent le statut socio-économique et la consommation de substances ne sont toujours pas clairs. Par exemple, le concept de statut socio-économique reste difficilement appréhendable du point de vue de l’adolescent et la question de la différence entre les genres demeure. Cette étude se propose d’analyser dans quelle mesure le statut socio-économique peut prédire, directement et par effet d’interaction avec l’estime de soi, autre prédicteur examiné, la consommation d’alcool et de substances illicites au sein des deux sexes. Des mesures auto-rapportées et standardisées ont été administrées à 330 adolescents, âgés de 14 à 17 ans, et provenant de différents types d’enseignement de la Fédération Wallonie-Bruxelles, respectivement 162 filles (moy. âge = 15,6 ans) et 168 garçons (moy. âge = 15,6 ans). A l’aide de statistiques réalisées par SPSS, nous pouvons premièrement montrer une différence significative dans la consommation de substances entre les filles et les garçons (t (328) = 2,21, p= 0,03). Deuxièmement, le statut socio-économique ne serait pas significatif chez les garçons (b = 0,48, 95% CI [-0,59, 1,56], t = 0,89, NS), tandis qu’il expliquerait marginalement la consommation de substances chez les filles (b = 0,11, 95% CI [-0,003, 0,21], t = 1,91, p = 0,06). D’autre part, la relation positive entre le statut socio-économique et la consommation de substances s’avèrerait plus forte lorsque les jeunes filles présentent des niveaux peu élevés d’estime de soi (b = -0,33, 95% CI [-0,06, -0,004], t = -2,27, p = 0,02). Cette étude se conclut par une discussion concernant l’implication de ces résultats, notamment en matière de compréhension des facteurs explicatifs de la consommation d’alcool et de substances illicites chez les filles et chez les garçons. [less ▲]

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See detailAdolescents et délinquance : Quelles représentations de la sexualité et de la pornographie, pour quelle sexualité ?
Puglia, Rosa ULg; Glowacz, Fabienne ULg

Conference (2014, May)

Bien que la pornographie ne soit pas un phénomène nouveau, ses supports, ses modalités d’accès, son public, etc. se sont vus modifiés suite à l’avènement des nouvelles technologies. Ainsi, de nos jours ... [more ▼]

Bien que la pornographie ne soit pas un phénomène nouveau, ses supports, ses modalités d’accès, son public, etc. se sont vus modifiés suite à l’avènement des nouvelles technologies. Ainsi, de nos jours, les adeptes de ce média peuvent d’un simple clic visionner une variété d’images et de films à caractère pornographique de manière anonyme et gratuite. Alors que de nombreuses questions se posent quant à l’influence de ces médias sur le développement psycho-sexuel et sur les conduites des adolescents, peu d’études y ont été consacrées. Avant de considérer la population délinquante, il était important d’évaluer la consommation pornographique dans une perspective développementale auprès d’une population d’adolescents. Nos recherches se sont centrées, d‘une part sur l’impact de l’accessibilité et de la visualisation de ces médias au niveau des représentations de la sexualité et de la pornographie, et d’autre part, sur l’influence de la consommation pornographique au niveau du développement psycho-sexuel et des pratiques sexuelles des adolescents. Une enquête a été menée auprès de 319 jeunes (150 filles) comprenant, en plus des items se rapportant à la sexualité et la pornographie, plusieurs tests évaluant des dimensions du fonctionnement psychologique et social (test de solitude, recherche de sensation, relations aux pairs, délinquance auto-révélée,... ). Des entretiens semi-directifs ainsi que les différents tests ont été proposés à 20 adolescents délinquants judiciarisés. Nos résultats mettent en évidence que la consommation pornographique influence les représentations (et réciproquement) et certains aspects des pratiques sexuelles des jeunes. Il ressort également que les adolescents délinquants (auto-révélés et judiciarisés) apparaissent comme plus vulnérables par rapport aux sollicitations de ces médias. [less ▲]

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See detailGrade retention at the transition to secondary school: A quasi-experimental study of its consequences on relationships with parents and peers
Lecocq, Aurélie; Mathys, Cécile ULg; Véronneau, Marie-Hélène

Conference (2014, May)

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See detailAlien plant species along watercourses in the Natura 2000 network
Monty, Arnaud ULg; Aimont, Hélène; Mahy, Grégory ULg

Conference (2014, May)

Natura 2000 is the centerpiece of EU nature and biodiversity policy. It is a European wide network of nature protection areas aiming at assuring the long-term survival of Europe's most valuable and ... [more ▼]

Natura 2000 is the centerpiece of EU nature and biodiversity policy. It is a European wide network of nature protection areas aiming at assuring the long-term survival of Europe's most valuable and threatened species and habitats. However, alien plants do not stop their spread at the border of protection areas and invasive plants are reported to threaten aquatic and riparian ecosystems. Our study aimed at assessing the plant invasion threat along watercourses within the Natura 2000 in Southern Belgium. A stratified random sampling, based on the natural region and the size of the watershed, was conducted. 187 sections of watercourses bank were visited between May and September 2013. For all recorded alien species, data were collected about local abundance, competitive impacts, regeneration potential and ecological conditions. 51 alien species were observed. Some were widespread (e.g. Impatiens glandulifera, with 17 % of linear banks invaded) whereas others were either rare or considered emergent alien species. Emergent species, showing low occurrence but high impact index, are appropriate target species for early detection programs and preventive management actions. Analyses showed that typical riparian species’ occurrence increased with the size of the watershed, indicating propagule pressure within protected areas through hydrochory. No link could be established between the presence of disturbance(s) and alien species in the considered N2000 sites. [less ▲]

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See detailLa mineuse de la tomate et ses risques agriculturaux
De Backer, Lara ULg; Verheggen, François ULg

Conference (2014, May)

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See detailSustainable Resource Availability : Ge, Ni, Al three contrasting stories
Pirard, Eric ULg

Conference (2014, May)

The sustainable availability of raw materials used in manufacturing advanced products is a question that consumers will raise more and more in the future. In order to answer this legitimate request it is ... [more ▼]

The sustainable availability of raw materials used in manufacturing advanced products is a question that consumers will raise more and more in the future. In order to answer this legitimate request it is mandatory to define characterization factors capable of taking into account the geological scarcity of an element but also the social and environmental impact of its exploitation and beneficiation. Recent studies (Vieira et al. 2012; Swart el al. 2013) have focused on decreasing ore grades as rough indicators, but clearly such indicators can be severely biased by breakthrough innovations in mining technologies as well as by high metal prices generated by increasing demand. In this paper, we will briefly review three metals that could technically be extracted from very different social and natural environments: Germanium is nowadays mainly a byproduct of coal burnt in China, but could as well be gained from alternative sources such as zinc sulfides. Aluminium is produced from bauxite with Gallium as a byproduct but could technically be extracted from alternative resources such as regionally available clays. Finally, the world nickel production follows two very different processing routes starting either from silicates (laterite deposits) or from sulfides (ultramafic magmas). By comparing the geological; environmental and social impact of mining operations for these three metals, we will try to show what is hidden behind simple ore grades and what indicators should be taken into account in a more complex analysis of sustainable availability. The intention is to build a geographical information system (GIS) of mineral resources and mining operations to help product manufacturers in properly selecting their raw materials providers. Vieira, M.D.M., Goedkoop, M.J., Storm, P. and Huijbregts, M.A.J., 2012, Ore grade decrease as a life cycle impact indicator for metal scarcity : The case of copper. Environ. Sci. Technol. 46, 12772-12778 Swart, P. and Dewulf, J., 2013, Quantifying the impacts of primary metal resource use in life cycle assessment based on recent mining data. Resources, Conservation and Recycling, 73, 180-187. [less ▲]

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See detailAlkaline hydrolysis for animal carcass disposal: a regulatory challenge
Van der Meulen, Karen; Custer, René; Houthoofd, Koen et al

Conference (2014, May)

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See detailAnalyse socio-cognitive des modes de schémas précoces inadaptés et des caractéristiques de personnalité au sein d’une population de femmes victimes de violences conjugales
Garcet, Serge ULg; Perick, Thomas ULg

Conference (2014, May)

La violence à l’égard des femmes fait depuis longtemps débat dans le champ de la victimologie. De la vision historique de la victime « coupable » à la victime « innocente » des mouvements féministes, les ... [more ▼]

La violence à l’égard des femmes fait depuis longtemps débat dans le champ de la victimologie. De la vision historique de la victime « coupable » à la victime « innocente » des mouvements féministes, les enjeux moraux déterminent le plus souvent les arguments des parties dans une dialectique militante, de revendication et de rapport de force. Se plaçant résolument dans une position scientifique, la présente étude analyse au sein d’une population de femmes victimes de violences conjugales rencontrées dans le cadre d’expertises pré-sententielles, l’influence des représentations précoces inadaptées (schémas) selon la classification de J. Young sur la perception de la relation. Dans une perspective sociocognitive, l’étude mesure la prévalence de différents schémas précoces dysfonctionnels et envisage comment ceux-ci contribuent chez la victime adulte au maintien d’une vision dévalorisée d’elle-même et d’un rapport inégalitaire à l’altérité propice à l’émergence de comportements violents. L’étude analyse également l’impact de ces schémas sur la construction de la personnalité adulte et met en évidence la fréquence de certains modes préférentiels de personnalité selon les classifications DSM-IV/V au sein de cette population de femmes victimes. [less ▲]

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See detailAméliorer la formation clinique en logopédie par un stage socle au sein de l'université
Martinez Perez, Trecy ULg; Willems, Sylvie ULg; Maillart, Christelle ULg

Conference (2014, May)

La formation clinique des étudiants en logopédie (orthophonie) occupe une place importante dans leur cursus. Cette formation se dispense principalement via des stages réalisés dans des structures ... [more ▼]

La formation clinique des étudiants en logopédie (orthophonie) occupe une place importante dans leur cursus. Cette formation se dispense principalement via des stages réalisés dans des structures extérieures au centre de formation. Si cette ouverture permet aux étudiants de se confronter à la réalité du terrain, elle implique en contrepartie une hétérogénéité des lieux de stage et, par conséquent, une hétérogénéité de la formation avec certaines compétences qui sont peu ou pas travaillées dans certains lieux de stage. Face à cette problématique, un stage « socle », garant d’un base commune préalable, est désormais proposé à tous les étudiants du Master 1 Logopédie de l’Université de Liège au sein de la clinique universitaire. Ce dispositif poursuit un double objectif : (a) permettre à tous les étudiants en logopédie d’accéder aux apprentissages de base nécessaires pour une pratique future de qualité, (b) par son design, accompagner l’étudiant dans le développement réflexif et intégré de plusieurs compétences professionnelles du logopède. Plus précisément, ce stage de 60H se réalise en binôme. Chaque binôme participe à cinq séances de quatre heures sur la réalisation d’un bilan logopédique. Par ailleurs, un système de caméra permet aux étudiants d’observer activement le bilan réalisé par un second binôme et sert de support pour une séance de feedback. En 2012-2013, l’évaluation du dispositif indique notamment que : pour 84% des étudiants, ce dispositif leur a permis d’apprendre et/ou de pratiquer des notions qui ne sont pas abordé par ailleurs dans leur parcours de formation ; pour 82% des étudiants, ce dispositif les a aidé à relier la pratique aux notions abordées aux cours ; 100% des étudiants pensent pouvoir utiliser ce qu’ils ont développé lors du dispositif dans leur pratique professionnelle. [less ▲]

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See detailSécurité alimentaire à Kinshasa. Analyse comparative des modes de consommation alimentaire des ménages selon les saisons
Muteba Kalala, Damien; Ntoto, Roger; Lebailly, Philippe ULg

Conference (2014, May)

Les résultats de l’étude montre qu’en général, les quantités consommées dans les ménages de Kinshasa ainsi que les apports énergétiques et protéiques sont déficitaires et en baisse. Ces quantités et ... [more ▼]

Les résultats de l’étude montre qu’en général, les quantités consommées dans les ménages de Kinshasa ainsi que les apports énergétiques et protéiques sont déficitaires et en baisse. Ces quantités et apports sont plus faibles en saison pluvieuse qu’en saison sèche. La situation est alarmante pour les ménages pauvres dont les quantités d’aliments consommées/individu/jour en saison pluvieuse sont inférieures à 500g avec les apports énergétiques estimés à 1.130 calories et 50 g de protéines. Il apparait donc que, c’est pendant la saison pluvieuse que les ménages surtout les plus pauvres déjà en insécurité alimentaire, y tombent davantage. C’est une sorte de période des « vaches maigres » pour ces Kinois. C’est la saison pluvieuse qui est donc la période indiquée et pouvant rendre plus pertinentes les interventions à caractère social ou humanitaire tant du Gouvernement Congolais que des autres partenaires. L’analyse qui découle des quantités consommées, des apports énergétiques et protéiques permet de confirmer qu’à Kinshasa, comme dans la quasi-totalité des pays du Tiers-Monde, les modes de consommation sont caractérisés par une forte consommation relative de céréales et/ou de racines et tubercules, complétées parfois par des produits riches en protéines, essentiellement les légumineuses. Il apparait aussi clairement que les modes de consommation des Kinois s’inspirent des modèles traditionnels ruraux. [less ▲]

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See detailLe redoublement scolaire rend-il les élèves plus agressifs? Etude quasi-expérimentale sur le redoublement scolaire en début de secondaire et ses conséquences sur l’agressivité
Mathys, Cécile ULg; Véronneau, Marie-Hélène; Lecocq, Aurélie

Conference (2014, May)

Le taux de redoublement scolaire est particulièrement élevé en Belgique. Bien que ses effets concernant les performances académiques soient régulièrement étudiés, les conséquences du redoublement scolaire ... [more ▼]

Le taux de redoublement scolaire est particulièrement élevé en Belgique. Bien que ses effets concernant les performances académiques soient régulièrement étudiés, les conséquences du redoublement scolaire sur l’adaptation psychosociale des élèves fait encore peu l’objet de recherches rigoureuses, notamment concernant le niveau d’agressivité des élèves qui ont vécu un redoublement. Par ailleurs, l’entrée en enseignement secondaire coïncide avec l’affirmation de nouveaux statuts sociaux pour les élèves et l’agressivité peut être une façon d’établir une hiérarchie au sein des groupes de pairs. L’objectif de cette étude est d’examiner si le redoublement scolaire affecte à court terme le niveau d’agressivité d’élèves se situant au début de leur cursus d’enseignement secondaire. Un protocole quasi-expérimental a été utilisé et deux groupes d’élèves comparables (doublants et promus) ont pu être crées grâce à des scores de propension sur base de 26 variables collectées. Des mesures auto-rapportées et standardisées ont été administrées sur deux semestres et un échantillon de 72 élèves provenant d’un établissement secondaire typique de la Fédération Wallonie-Bruxelles (moy. âge = 12.9 ans, 47.2% de filles, 70% d’origine belge) a été identifié. Des analyses univariées réalisées par SPSS (F (1,67) = 6,98, p = 0,01) révèlent que durant l’année suivant le redoublement scolaire, les élèves ayant doublé ne montrent pas de diminution de leur niveau d’agressivité (t (35) = 0,50, ns), contrairement aux élèves ayant été promus (t (32) = 3,32, p = 0,01). En outre, ces résultats sont significativement « palpables » comme l’indique la taille de l’effet plutôt élevée (d = .64). Ces résultats sont discutés en termes d’implications, notamment concernant l’importance de continuer à maintenir un statut social pour les élèves ayant vécu une expérience de redoublement au début de leur cursus en enseignement secondaire, contrairement aux élèves qui ont été promus. [less ▲]

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See detailProcessing of alloy Ti-6Al-4V and of stainless steel 316L by Laser Beam Melting
Mertens, Anne ULg; Paydas, Hakan ULg; Reginster, Sylvie ULg et al

Conference (2014, May)

Additive manufacturing processes such as Selective Laser Melting (SLM) appear very promising in view of the economic production of near-net-shape, complex and (almost) fully dense parts from metallic ... [more ▼]

Additive manufacturing processes such as Selective Laser Melting (SLM) appear very promising in view of the economic production of near-net-shape, complex and (almost) fully dense parts from metallic materials such as Ti alloys and stainless steels. Practically, in SLM, a metallic powder is deposited layer-by-layer in a powder bed and then molten locally according to the desired shape. An important feature of this process is that the structure undergoes an ultra-fast cooling once the beam leaves the working zone, thus giving rise to strongly out-of-equilibrium microstructures. In the case of Ti alloy Ti-6Al-4V, in particular, the microstructural anisotropy resulting from the epitaxial growth of the newly deposited layer on the material previously solidified has been shown to exert a very strong influence on the mechanical properties [1] In the present work, the thermophysical behaviour of Ti-alloy Ti-6Al-4V and of stainless steel 316L has been characterised in details, in order to reach a better understanding of the phenomena controlling the microstructures and mechanical properties of parts. In particular, the thermal conductivity of Ti-alloy Ti-6Al-4V and of stainless steel 316L at high temperature has been determined by combining dilatometry, Differential Scanning Calorimetry (DSC) and laser flash diffusivimetry based on Laplace’s equation. Since Ti-alloy Ti-6Al-4V and stainless steel 316L exhibit quite different physical behaviours, their careful comparison is shown to shed more light into the role of phenomena such as epitaxial growth, out-of-equilibrium phase transformations and/or internal stresses in the additive manufacturing of metallic materials. [less ▲]

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See detail« La flexicurité : une politique des idées ? Regards croisés d’acteurs institutionnels belges en 2013 »
Beuker, Laura ULg; Gérard, Julie ULg; Orianne, Jean-François ULg

Conference (2014, May)

Cette communication porte sur la traduction, en Belgique, d’une politique européenne de l’emploi – la flexicurité – par différents acteurs institutionnels. À partir d’une analyse documentaire et d’une ... [more ▼]

Cette communication porte sur la traduction, en Belgique, d’une politique européenne de l’emploi – la flexicurité – par différents acteurs institutionnels. À partir d’une analyse documentaire et d’une vingtaine d’entretiens semi-directifs, nous étudierons la manière dont ces acteurs s’approprient et interprètent la flexicurité. Nous nous appuierons principalement sur les apports récents de la sociologie de l’action publique, en particulier l’approche cognitive des politiques publiques (Surel, 2000 ; Muller et Surel, 1998) et l’européanisation des politiques d’emploi (Palier et Surel, 2007 ; 2010). Nous montrerons que cette appropriation a donné lieu, en Belgique, à une transformation de sens conféré à la sécurité, celle-ci étant dorénavant substitué à celui de la flexibilité. [less ▲]

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See detailQuand les femmes veulent leur part. L'héritage et la justice à Cotonou
Andreetta, Sophie ULg

Conference (2014, May)

Depuis plusieurs années maintenant, le Bénin tente de réaliser l’un des principes clés des normes internationales : l’égalité. Evoqué dans la constitution de 1990, ce principe est aujourd’hui au centre de ... [more ▼]

Depuis plusieurs années maintenant, le Bénin tente de réaliser l’un des principes clés des normes internationales : l’égalité. Evoqué dans la constitution de 1990, ce principe est aujourd’hui au centre de nombreuses modifications législatives visant, entre autres, à ‘moderniser’ les textes datant pour la plupart de la période coloniale. Parmi ces derniers, le Code des Personnes et de la Famille réforme le droit civil en matière de divorces, de garde d’enfants, et de successions. C’est cette dernière question qui retiendra mon attention. En effet, alors que dans la plupart des coutumes, les femmes n’héritent pas des biens immeubles, cette nouvelle loi déclare tous les héritiers égaux, accordant également au conjoint survivant la pleine propriété du quart de la masse successorale. Je me pencherai donc sur le parcours de ces femmes qui recourent à la justice pour « réclamer leur part » du patrimoine successoral. Pourquoi décident-elles de s’opposer à leurs familles ? Quels sont leurs intermédiaires ? Quels sont les différents forums possibles, les étapes préalables au tribunal ? Comment interprètent-elles, ou utilisent-elles le droit étatique ? Enfin, une fois le tribunal saisi, c’est également la question de l’application des principes du droit qui se pose. Quels sont les arguments des uns et des autres à l’audience ? Comment les juges parviennent-ils à trancher? Mais surtout, comment leurs décisions sont-elles mises en œuvre au-delà du tribunal ? [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

Conference (2014, April 30)

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 detailRetrieval of HCHO from MAX-DOAS measurements at the high-altitude alpine station of Jungfraujoch (46.5°N, 8.0°E)
Hendrick, François; Fayt, Caroline; Franco, Bruno ULg et al

Conference (2014, April 30)

Formaldehyde (HCHO) plays an important intermediate role in the atmospheric photo-oxidation pathways. It is produced during the oxidation of methane and many non-methane volatile organic compounds (NMVOCs ... [more ▼]

Formaldehyde (HCHO) plays an important intermediate role in the atmospheric photo-oxidation pathways. It is produced during the oxidation of methane and many non-methane volatile organic compounds (NMVOCs) which participate to the formation of tropospheric ozone and secondary organic aerosols. HCHO is also directly released by biomass burning and fossil fuel combustion and to a lesser extent by vegetation. Measuring this species is therefore of major importance for air quality and climate change monitoring. In this presentation, HCHO near-surface concentrations and vertical column densities are retrieved from MAX-DOAS measurements performed at the high-altitude station of Jungfraujoch (3580m asl) in the Swiss Alps from July 2010 till December 2012. Although being most of the time located in the free troposphere, this station can be temporarily affected by pollution events originating from the valley, leading to a local increase of air pollutant concentrations. The capability of the MAX-DOAS technique to retrieve HCHO in such high-altitude location is investigated. The spatial representativeness and the impact of cloud cover on the measurements is also discussed. For verification purpose, our retrievals are compared to collocated FTIR observations, taking into account the difference in vertical resolution between both techniques. Simulations from the 3D-CTM IMAGES are also used to further assess the observed seasonal and diurnal cycles of HCHO surface concentration and vertical column. [less ▲]

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See detailRecords of human activity during the late-Holocene in the soils of the African dense humid forest
Morin-Rivat, Julie ULg; Biwolé, Achille; Bourland, Nils ULg et al

Conference (2014, April 30)

Recently, several authors gathered data about the presence of past human populations in tropical regions covered by dense forest nowadays. In central Africa, there is a growing body of evidence for past ... [more ▼]

Recently, several authors gathered data about the presence of past human populations in tropical regions covered by dense forest nowadays. In central Africa, there is a growing body of evidence for past human settlements along the Atlantic coast, but very little information is available further inland. In this perspective, soil records seem to be the most appropriated so as to appraise the spatial and temporal extent of human activity in the African dense humid forest. In this paper, we thus aimed to present a synthesis of the archaeological and archaeobotanical data obtained during several fieldwork campaigns in an archaeologically unexplored area of 200,000 km² located in southern Cameroon and the northern Republic of Congo. A total of 275 test pits, among them 30 pedological pits up to 150 cm deep, were excavated in the study area. So as to get a long temporal scale as well as a fine resolution spatial scale, we quantified wood charcoal and charred endocarps in soil samples by layers of 10 cm taken for 100 pits located along transects of systematic sampling. Spatial projections were performed using statistics together with multivariate analyses. AMS radiocarbon dating allowed interpreting the temporal framework. Evidence of past human activities through either artifacts or charred botanical remains was observed in all pits, in particular with the ubiquitous presence of charcoal at each site. Main charcoal peaks were interpreted as fields (slash-and-burn agriculture) in the vicinity of ancient villages, the later marked by the presence of both potsherds and oil palm endocarps. The dichotomy of these kinds of activities may have impacted differentially the environment during the past. The set of 73 radiocarbon dates extending from 15,000 BP to the present time provided more dates in the late-Holocene showing a bimodal distribution which was interpreted as two phases of human expansion with an intermediate phase of population crash. The 2300–1300 BP phase is correlated with the migrations of supposed farming populations from northwestern Cameroon. Between 1300 and 670 BP, less material could be dated. Following that population collapse, the 670–20 BP phase corresponds to a new period of human expansion known as the Late Iron Age. The dates obtained support the established chronology reported for whole central Africa. This study underlines the necessity of fieldwork efforts and of the usefulness of archives sealed in soil records so as to bring new, extensive and precise evidence of human activities in the Congo Basin. [less ▲]

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See detailDynamique des forêts irrégulières et mélangées: de la modélisation aux recommandations sylvicoles
Ligot, Gauthier ULg

Conference (2014, April 29)

Close-to-nature management of forests has been increasingly advocated and practiced. However forest managers often face difficulties in maintaining the mixture of species with different shade tolerance ... [more ▼]

Close-to-nature management of forests has been increasingly advocated and practiced. However forest managers often face difficulties in maintaining the mixture of species with different shade tolerance. We studied this issue in uneven-aged acidophile medio-European beech forests. In these forests, while forest management has achieved regular timber production, it has rarely succeeded in promoting a diversified natural regeneration. In view of this, our objective is to refine our knowledge about the dynamic of uneven-aged mixed forests using a modelling approach. A set of consistent models were carried out to describe stand dynamic with, in particular, models of regeneration growth and light interception. The models were then implemented in a simulator in order to perform prospective analysis. In contrast to expectations, we found that saplings of beech, the shade-tolerant species, had the highest height growth rate at all light levels. Beech saplings reached an optimum growth at transmittance of 10%, whereas oak saplings needed more than 20%. These results indicate that oak saplings are systematically outcompeted by beech saplings across the light gradient. Thus, the control of canopy opening is not sufficient to promote the natural regeneration of oak beneath a stand also containing beech. Taking into account these latter results, we compared cutting strategies varying in type and intensity. Creating gaps of about 500 m² provided adequate light for small regeneration clumps. Cutting from below, species-specific cutting and uniform cutting were also appropriate but uniform cutting required higher harvest intensity. Cutting from above weakly increased understory light and promoted rather shade tolerant species. Finally we provided indications on different strategies that promote the regeneration of less-shade tolerant species, depending on the spatial aggregation of saplings, and the desired post-harvest stand structure and composition. [less ▲]

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See detailIntermediaries, transport costs and interlinked transaction
Tharakan, Joseph ULg

Conference (2014, April 29)

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Peer Reviewed
See detailDecoding implicit information from the soil map of Belgium and implications for spatial modelling and soil classification
Dondeyne, Stefaan; Legrain, Xavier ULg; Colinet, Gilles ULg et al

Conference (2014, April 29)

A systematic soil survey of Belgium was conducted from 1948 to 1991. Field surveys were done at the detailed scale of 1:5000 with the final maps published at a 1:20,000 scale. Soil surveyors were ... [more ▼]

A systematic soil survey of Belgium was conducted from 1948 to 1991. Field surveys were done at the detailed scale of 1:5000 with the final maps published at a 1:20,000 scale. Soil surveyors were classifying soils in the field according to physical and morphogenetic characteristics such as texture, drainage class and profile development. Mapping units are defined as a combination of these characteristics but to which modifiers can be added such as parent material, stoniness or depth to substrata. Interpretation of the map towards predicting soil properties seems straight forward. Consequently, since the soil map has been digitized, it has been used for e.g. hydrological modelling or for estimating soil organic carbon content at sub-national and national level. Besides the explicit information provided by the legend, a wealth of implicit information is embedded in the map. Based on three cases, we illustrate that by decoding this information, properties pertaining to soil drainage or soil organic carbon content can be assessed more accurately. First, the presence/absence of fragipans affects the soil hydraulic conductivity. Although a dedicated symbol exits for fragipans (suffix “...m”), it is only used explicitly in areas where fragipans are not all that common. In the Belgian Ardennes, where fragipans are common, their occurrence is implicitly implied for various soil types mentioned in explanatory booklets. Second, whenever seasonal or permanent perched water tables were observed, these were indicated by drainage class “.h.” or “.i.”, respectively. Stagnic properties have been under reported as typical stagnic mottling – i.e. when the surface of soil peds are lighter and/or paler than the more reddish interior – were not distinguished from mottling due to groundwater gley. Still, by combining information on topography and the occurrence of substratum layers, stagnic properties can be inferred. Thirdly, soils with deep anthropogenic enriched organic matter (Anthrosols) are distinguished for their specific profile development (code “..m”). Obviously, when assessing soil organic carbon content these soil types need particular consideration. Soils in the Campine region with anthropogenic layers only 30 to 40 cm thick, not being Anthrosols, got a specific suffix code (“. . . 3”). Still, as these soils may have a buried Ah horizon of up to 20 cm, their soil organic carbon content can be comparable to those of Anthrosols. The buried Ah horizon is however not explicitly mapped; its presence needs to be inferred from other environmental information. In conclusion, conventional soil maps convey more information than what transpires from just the explicit legend’s semantics. Although a challenge, decoding the implicit information should be particularly useful for spatial modeling. The cases also point to the importance of classifying soil characteristics explicitly, wherever possible, and in particularly when soil maps are integrated into geographical information systems. [less ▲]

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See detailTowards deep changes for a more resilient farming system: Examining roles farmers, science and citizens can play in transition
Klaedtke, Stephanie ULg

Conference (2014, April 29)

This lecture considers the complexity of challenges of the agricultural transition from the perspective of farmers, who act at the intersection between the ecology, economy and policy. The lecture will ... [more ▼]

This lecture considers the complexity of challenges of the agricultural transition from the perspective of farmers, who act at the intersection between the ecology, economy and policy. The lecture will start by providing an overview on the resource requirements for our global production chains of life stock and meat, grain and legume farming and say some words on the human diet, and food and feed conversion efficiency of energy-intake through food. This lecture also places a fresh emphasis on the development of local knowledge and locally specific arming and nutrition practices that are adapted to local environments, as a necessary complement to agricultural science striving to make universal claims. This leads on to basic insights on needs for knowledge production in agriculture, and merits and limitations of action research and engaged research, raising questions on how farmers, scientists and citizens might better collaborate to inform choices in food production and consumption. For the future there are some indications on a new trend on new more decentralised governance of the food system including citizen’s involvement in French organic certification and Community based Auditing and citizens science in communities in Australia to work with farmers on reducing environmental impacts and address ensuing trade-offs for farmers as a community. [less ▲]

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See detailQuasi-periodic flares in Jupiter's aurora : new results
Bonfond, Bertrand ULg; Grodent, Denis ULg; Badman, Sarah et al

Conference (2014, April 29)

Two recent Hubble Space Telescope observation campaigns have been dedicated to the Jovian Far-UV aurora (GO 12883 – PI: D. Grodent and GO 13035 – PI: S. Badman). Both of them made use of the Time-Tag mode ... [more ▼]

Two recent Hubble Space Telescope observation campaigns have been dedicated to the Jovian Far-UV aurora (GO 12883 – PI: D. Grodent and GO 13035 – PI: S. Badman). Both of them made use of the Time-Tag mode of the Space Telescope Imaging Spectrograph (STIS), a high time resolution mode which allows to observe temporal variations on timescales of tens of seconds. In the present study, we focus on sudden and spectacular bursts of auroral emissions taking place in the active region located poleward of the main emissions and called “flares”. A previous study, based on only two image sequences acquired with rather unfavorable viewing angles, showed that these flares could reappear quasi-periodically on time scales of 2-3 minutes. Phenomena with similar timescales have been identified by in-situ spacecraft in relativistic electron and radio data as well as in reconnection signatures, for example. But the physical mechanism behind these ubiquitous signatures remains to be unveiled. Here we make use of the most recent and much larger data set to study in further details the occurrence rate, the period, the location, the extent and the motion of these quasi-periodic flares and to compare their behavior in both hemispheres. Quantifying these parameters allows us to narrow down the possibilities among likely explanations and provide a tentative scenario for these short timescale quasi-periodic features. [less ▲]

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See detailCode du développement territorial et politique foncière
Fontaine, Pierre; Halleux, Jean-Marie ULg

Conference (2014, April 28)

Detailed reference viewed: 16 (2 ULg)
Peer Reviewed
See detailContribution of a new active faults map and sedimentary cores to the characterization of seismogenic sources in an interdisciplinary approach (Western Gulf of Corinth, Greece)
Beckers, Arnaud ULg; Hubert, Aurelia ULg; Beck, Christian et al

Conference (2014, April 28)

The Corinth rift is one of the fastest spreading rifts on Earth. 5 earthquakes of magnitude greater than 5.8 occurred during the last 40 years. The question of seismic hazard is consequently particularly ... [more ▼]

The Corinth rift is one of the fastest spreading rifts on Earth. 5 earthquakes of magnitude greater than 5.8 occurred during the last 40 years. The question of seismic hazard is consequently particularly relevant. Despite a long earthquake catalogue, estimations of earthquake hazard remain problematic because of the difficulty to associate each historical event to one of the many active faults mapped in the area. Consequently, combining seismology, history and paleoseismology in an interdisciplinary approach is here necessary and is the goal of the ANR-SISCOR project. In this framework, we investigated the offshore sediments in order to (1) better constraint the length of the active offshore faults, and (2) look for sedimentary signature of historical earthquakes. 600 km of high resolution seismic reflexion data have been acquired during two surveys and 12 short gravity cores have been retrieved. The latters are 0.5 to 1 m long, allowing us to analyze about 500 yrs of sedimentation. Two new faults potentially able to trigger M>5.5 earthquakes have been mapped in the northern part of the gulf based on seismic data. Sedimentary events (turbidites and mud flows) have been identified in some cores, essentially in the deep basin and in a 180m-deep sub-basin close to the northern coast. The comparison with the critically reviewed historical records shows that some of these events could have been triggered by historical earthquakes. The link between these potential earthquakes sedimentary signatures, historical events and active faults is discussed based on intensity maps and our new active fault map. [less ▲]

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See detailThe age of river-transported carbon: new data from African catchments and a global perspective
Marwick, TR; Tamooh, F; Teodoru, C et al

Conference (2014, April 27)

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See detailTemporal variability and spatial dynamics of CO2 and CH4 concentrations and fluxes in the Zambezi River system
Teodoru, C; Borges, Alberto ULg; bouillon, S et al

Conference (2014, April 27)

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See detailDisproportionate contribution of riparian inputs to organic carbon in freshwater systems
Marwick, TR; Van Acker, K; Darchambeau, François ULg et al

Conference (2014, April 27)

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See detailPerception of melodic accuracy in occasional singers: role of pitch fluctuations?
Larrouy, Pauline ULg; Pfordresher, Peter Q

Conference (2014, April 26)

When listening to operatic singers performances, our perception of vocal pitch accuracy is influenced by several acoustical parameters such as the fluctuation of the fundamental frequency (i.e vibrato ... [more ▼]

When listening to operatic singers performances, our perception of vocal pitch accuracy is influenced by several acoustical parameters such as the fluctuation of the fundamental frequency (i.e vibrato). In the case of occasional singers, produced pitch is likewise not constant, but the fluctuations in such cases tend not to involve vibrato but to instead involve “scoops” at the beginning and ends of tone, as well as other forms of instability. However, little is known about the fluctuations that characterize occasional singers (including poor-pitch singers) and to what degree these fluctuations influence perception of pitch accuracy. We report results of ongoing research designed to address these issues. First, we describe a descriptive model used to identify perturbations of F0 in occasional singers that differ between accurate and poor-pitch singers. Next, we report results of recent experiments that explore the influence of the pitch fluctuations described by the model on the perception of pitch accuracy. [less ▲]

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Peer Reviewed
See detailDiagrams for ampliative reasonings
Leclercq, Bruno ULg

Conference (2014, April 26)

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See detailHow to locate intermodal terminals for achieving economic and environmental competitiveness?
Mostert, Martine ULg; Limbourg, Sabine ULg

Conference (2014, April 25)

Europe has a strong commitment to the development of competitive and sustainable transportation. An intermediate objective cited in the “White Paper” is to shift 30% of 300 km and above road freight ... [more ▼]

Europe has a strong commitment to the development of competitive and sustainable transportation. An intermediate objective cited in the “White Paper” is to shift 30% of 300 km and above road freight transportation to more environmentally-friendly modes of transport such as rail and water by 2030. Improving and expanding the intermodal network is one way to achieve this goal. However, intermodal transport requires intermodal terminals where the transfer from one mode to another can occur. The location of those terminals is of strategic importance for the competitiveness of intermodal transport. The objective of this paper is therefore to develop a network design model which allows the optimal location of intermodal terminals to be determined, subject to both economic and environmental efficiency. Three possible combinations are considered: (i) Road-only, (ii) Intermodal transport using road (drayage) and rail (long-haul) and (iii) Intermodal transport using road (drayage) and inland waterways (long-haul). External costs are also included in the analysis, i.e. costs that are generated by an economic agent but supported by other agents of the society. This strategy is in line with the willingness of Europe to internalize external costs. The developed model can be used to test how modal split is influenced by the undertaken policies, such as internalizing external costs in the transportation costs. Tests are carried out on the case study of Belgium. [less ▲]

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See detailNanostructured catalysts by sol-gel process
Lambert, Stéphanie ULg; Heinrichs, Benoît ULg

Conference (2014, April 25)

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See detail"Types de productions langagières" et canevas de séquences didactiques en langues modernes
Simons, Germain ULg; Pagnoul, Pierre ULg

Conference (2014, April 25)

Cette communication était structurée en quatre grands volets. Dans le premier, nous avons exploré la notion de "genre" et celle de "type de production langagière" ainsi que leur présence ou absence dans ... [more ▼]

Cette communication était structurée en quatre grands volets. Dans le premier, nous avons exploré la notion de "genre" et celle de "type de production langagière" ainsi que leur présence ou absence dans les prescrits légaux (référentiels, programmes, outils d'évaluation) en langues modernes en Fédération Wallonie-Bruxelles mais aussi dans le Cadre européen commun de référence pour les langues. Dans le deuxième volet, nous avons présenté et analysé le document "Familles de tâches en langues modernes" où apparaît, pour la première fois, la notion de "types de productions langagières à dominante... descriptive/informative, incitative/injonctive, narrative et argumentative", et avons tenté une clarification opérationnelle des notions de genre et de productions langagières en didactique des langues modernes. Dans le troisième volet, nous avons présenté deux canevas didactiques, un linéaire et l'autre par situation-problème, et avons montré en quoi ce dernier se prêtait particulièrement bien au travail sur le genre. Le concept de "noticing the gap" a été ici convoqué et nous avons fourni un exemple de DEBAT organisé avec la technique dite de "l'aquarium", procédé didactique destiné à mettre tous les élèves à la tâche. Enfin, dans le quatrième et dernier volet, nous avons évoqué les problèmes liés à ce champ de recherche sur le genre et avons proposé quelques pistes de solutions. Différentes références bibliographiques relatives aux quatre parties de l'exposé ont également été proposées au terme de la communication. [less ▲]

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See detailTowards an Archaeological Information System: improving the core data model
Van Ruymbeke, Muriel ULg; Carré, Cyril ULg; Delfosse, Vincent ULg et al

Conference (2014, April 25)

Grounded on archaeological information modeling works undertaken at the Geomatics Unit of the University of Liege, this paper goes a step further in handling time and function imperfection, interpretative ... [more ▼]

Grounded on archaeological information modeling works undertaken at the Geomatics Unit of the University of Liege, this paper goes a step further in handling time and function imperfection, interpretative sequences and people interacting with historical objects. Designed in 2011, the initial model already gathered both geometrical and historical information. It was partially based on the urban data standard City GML mainly for interoperability purposes. Its specificity, the version concept, allowed multiple geometries experiments. That property enabled us to handle geometrical ambiguity and incompleteness. To validate this model, and in a showcase purpose, a first prototype has been realized. One year later this prototype’s model has been improved to manage in a better way all objects’ versions and possible representations. Until now, this model integrates and manages imperfect archaeological data but only partially: the version concept being only dedicated to express geometric ambiguity or imprecision. Henceforth, with the version notion widening, we propose to encompass function and time imperfection as well. It is an important progress because on an archaeological point of view, time and function are quite generally incomplete, uncertain, imprecise or contradictory. Another enhancement must be highlighted: the agent enlistment. Historical characters, on one hand, and contemporaneous people (like authors, archaeologists etc.) on another hand are key elements of archaeological game pieces. Finally, we will describe the way of structuring versions into interpretative sequences. With those improvements, we wish to carry on feeding the scientific debate as much as drafting Archaeological Information Systems. [less ▲]

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See detailLes genres en didactique des langues étrangères et en littérature pour la jeunesse. Introduction à la journée du 25 avril 2014.
Simons, Germain ULg; Delbrassine, Daniel ULg

Conference (2014, April 25)

Dans cette brève communication introductive, nous avons d'abord expliqué les objectifs de cette journée sur le genre dans le domaine de la didactique des langues étrangères et de la littérature pour la ... [more ▼]

Dans cette brève communication introductive, nous avons d'abord expliqué les objectifs de cette journée sur le genre dans le domaine de la didactique des langues étrangères et de la littérature pour la jeunesse. Nous avons ensuite dévoilé le programme de la journée. Enfin, nous avons brièvement présenté les deux orateurs extérieurs, Mme M. Jacquin (Université de Genève) et M. H.-H. Ewers (Université de Francfort). [less ▲]

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See detailLa démarche RAI, historique, philosophie, outils
Delye, Samuel ULg; Maggi, Patrick ULg; Gosset, Christiane ULg

Conference (2014, April 25)

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See detailExemples de séquences didactiques axées sur différents genres : introduction
Simons, Germain ULg

Conference (2014, April 25)

Cette brève communication visait à introduire et à contextualiser cinq séquences didactiques articulées autour de la notion de genre. Ces séquences, conçues et mises en pratique par d'anciens étudiants de ... [more ▼]

Cette brève communication visait à introduire et à contextualiser cinq séquences didactiques articulées autour de la notion de genre. Ces séquences, conçues et mises en pratique par d'anciens étudiants de l'ULg dans le cadre de l'AESS/du Master à finalité didactique ou du CAPAES, portaient sur le débat régulé (anglais), le reader digest (anglais et néerlandais), l'entretien d'embauche (espagnol), la Kurzgeschichte (allemand), le Krimi (allemand/langue maternelle). Cette introduction a également permis de rappeler les grandes phases du canevas didactique par situation-problème. [less ▲]

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See detailIntroduction aux deux journées d'études : "Questions de genres"
Letawe, Céline ULg; Simons, Germain ULg

Conference (2014, April 24)

Lors de cette brève introduction, nous avons a) rappelé les objectifs de l'Entité de recherche structurelle en Langues et littératures modernes de l'ULg ; b) fourni quelques éléments généraux sur l'objet ... [more ▼]

Lors de cette brève introduction, nous avons a) rappelé les objectifs de l'Entité de recherche structurelle en Langues et littératures modernes de l'ULg ; b) fourni quelques éléments généraux sur l'objet de recherche "genre" ; c) présenté le programme complet des deux journées dans les quatre grands domaines : littérature (en ce compris la littérature pour la jeunesse), linguistique, traduction, didactique, et d) remercié les différents partenaires qui ont contribué à la réalisation de ce symposium. [less ▲]

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See detailLogistics hub: the case of Liège
Limbourg, Sabine ULg; Mostert, Martine ULg; Paquay, Célia ULg

Conference (2014, April 24)

A logistics hub can be defined as a specific area where all the activities relating to transport, logistics and goods distribution are carried out. With its central location in Europe, highly developed ... [more ▼]

A logistics hub can be defined as a specific area where all the activities relating to transport, logistics and goods distribution are carried out. With its central location in Europe, highly developed infrastructures, airport and inland terminals, the region of Liège claims to be a logistics hub. This paper applies a strategic decision model based on seven relevant criteria (infrastructure, proximity to market, land availability, government and industry support, labour supply, origin/destination distances and congestion) to assess the efficiency of the logistics hub of the region of Liège. Two SWOT analyses are performed in parallel to evaluate the positions of Liège Airport and of the inland freight hub, Trilogiport, in relation to their own performances and the competition. The two main development factors of inland freight hubs are considered: the possibility of modal shift from road transport to more environmentally friendly transportation modes and the avoidance of the congestion of the two seaport areas of Antwerp and Rotterdam. This article concludes by highlighting that the bid of the region of Liège and its characteristics should contribute to a more efficient intermodal transport in Europe, helping to boost the distribution of products, and at the same time, encourage the reduction of greenhouse gas emissions. However, the development of Liège as an inland freight hub depends on its ability to generate a critical mass, notably thanks to the local businesses, in order to realise economies of scale. [less ▲]

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Peer Reviewed
See detailEnforcement of accounting standards, financial crisis, and their impact on impairment of non financial assets
Yammine, Mira ULg; Olivier, Henri ULg

Conference (2014, April 24)

The consistent application of IFRS is a concern for the different users of financial statements. In this context this study aims to investigate the impact exercised by the enforcement of accounting ... [more ▼]

The consistent application of IFRS is a concern for the different users of financial statements. In this context this study aims to investigate the impact exercised by the enforcement of accounting standards and the financial crisis on the consistent application of IAS 36 `impairment of assets¿. Listed companies from17 European countries applying IFRS are selected. Two groups of countries are selected based on government indicators namely rule of law, control of corruption, regulatory quality, and government effectiveness. Enforcement of accounting standards is determined from a survey addressed to the institutional oversights bodies that supervise and enforce accounting standards applications in each country. We find that the enforcement of accounting standards has decreased the impairment of assets registrations. But this observation appears to be true only in high government indicators countries. In these same countries the financial crisis has a positive impact on the impairment of assets magnitude. [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 detailStudy of a solar concentrator for space based on a diffractive/refractive optical combination
Michel, Céline ULg; Loicq, Jerôme ULg; Thibert, Tanguy ULg et al

Conference (2014, April 16)

The present work proposes a theoretical optical study of a new planar solar concentrator for space applications. The concentrator focuses light onto three spatially separated photovoltaic cells (three ... [more ▼]

The present work proposes a theoretical optical study of a new planar solar concentrator for space applications. The concentrator focuses light onto three spatially separated photovoltaic cells (three single-junctions, dedicated to two different light spectra), allowing for independent control of the output power of each cell. The design, based on a blazed diffraction grating superimposed on a Fresnel lens, combines advantages of both spectral splitting and light focusing. Theoretical model and optimization of the optical design are presented, including the variation of the grating period along the lens. Numerical results are detailed, highlighting the possibility to design a concentrator at more than 10× for each cell, with an optical efficiency of ~71% and less than 10% of losses for tracking errors < ±0.85°. A thermal study completes the work, as well as a first theoretical comparison with a planar Fresnel based solar concentrator focusing on a GaAs cell. [less ▲]

Detailed reference viewed: 20 (6 ULg)
See detailPelvic neuroanatomy
Bonnet, Pierre ULg

Conference (2014, April 15)

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Peer Reviewed
See detailImproving our vision on human cadaveric decomposition chemistry
Stefanuto, Pierre-Hugues ULg; Stadler, S; Perrault, K et al

Conference (2014, April 15)

Detailed reference viewed: 17 (2 ULg)
See detailThe paravesical and para rectal space, parameter and paracervix
Bonnet, Pierre ULg

Conference (2014, April 15)

Detailed reference viewed: 8 (1 ULg)
See detailThe anatomy of the internal iliac artery
Bonnet, Pierre ULg

Conference (2014, April 15)

Detailed reference viewed: 4 (0 ULg)
See detailThe vascular anatomy of the para-aortic spaces
Bonnet, Pierre ULg

Conference (2014, April 15)

Detailed reference viewed: 6 (0 ULg)
See detailStudy of an undershoot in chlorophyll fluorescence signal after a saturating pulse in PAM measurements
Fratamico, Anthony ULg; Cardol, Pierre ULg; Tocquin, Pierre ULg et al

Conference (2014, April 14)

In 1989, Larcher and Neuner have reported the observation of a sudden reversible drop in modulated chlorophyll fluorescence measurements (PAM) immediately after a saturating pulse, and called it “low ... [more ▼]

In 1989, Larcher and Neuner have reported the observation of a sudden reversible drop in modulated chlorophyll fluorescence measurements (PAM) immediately after a saturating pulse, and called it “low-wave”. 25 years later, whereas some papers reported this phenomenon as a trivial detail, scarcely two works have investigated the origin of this particular signal, in which a link with a low CO2 availability seems clear. Our work on Haematococcus pluvialis, a freshwater green microalga, provides a new point of view on this fluorescence undershoot, caused by a rapidly established non-photochemical quenching. We have demonstrated that in the light-adapted state, a low-wave after a saturating flash can be considered as a consequence of an induction process engaged in response to the brief light increase under low CO2 conditions. The non-photochemical quenching during low-waves was found to be dependent on electron transport to oxygen during the preceding flash. Moreover, in conditions in which low-waves were observed in the light-adapted state, the fluorescence induction kinetics in the first minute of lighting after dark-adaptation presented also a reversible strong drop. Nevertheless, at the stationary state, oxygen production and photochemical yield of photosystem II were not affected. Providing a better understanding of the processes underlying low-waves, our work also draws attention on the effect of CO2 concentration on the onset of photosynthesis. [less ▲]

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See detailCumulative effect of Aox1 inactivation and N source modulation on the cellular proteome of Chlamydomonas reinhardtii - New insights in the metabolic interconnexion between respiration and photosynthesis
Gerin, Stéphanie ULg; Mathy, Grégory; Franck, Fabrice ULg

Conference (2014, April 14)

In Chlamydomonas reinhardtii, the Aox1 gene encoding the mitochondrial alternative oxidase (AOX) is tightly regulated by the N source: its transcription is stimulated by nitrate and repressed by ammonium ... [more ▼]

In Chlamydomonas reinhardtii, the Aox1 gene encoding the mitochondrial alternative oxidase (AOX) is tightly regulated by the N source: its transcription is stimulated by nitrate and repressed by ammonium. AOX has been proposed to play a key role in regards to the N source by acting as a trigger factor for the TCA cycle to promote the production of reduced cofactors which, together with photo-generated reductant, could contribute to support nitrate assimilation. In the present work, the cellular proteomes of wild-type and AOX-deficient strains grown either on nitrate or ammonium in the presence of acetate have been compared using two dimensional-differential in-gel electrophoresis (2D-DIGE) coupled to hierarchical clustering and ANOVA-2 statistical analyses in order to further investigate the physiological role(s) of AOX, particularly in regards to the N source. The dramatic up-regulation of chloroplastic components of the carbon-concentrating mechanism (CCM) in response to Aox1 inactivation importantly suggests that AOX plays a key role in the CCM in both N sources by allowing the production of CO2 through the TCA cycle. The concomitant down-regulation of photorespiratory enzymes in cells lacking AOX indicates that such an induction of the CCM could actually be sufficient to over-compensate the effects of AOX deficiency on CO2 availability in the local environment of Rubisco and maintain high rates of inorganic carbon fixation despite lower TCA cycle-mediated CO2 production. The global overexpression of diverse photosynthetic chain and Calvin cycle components in cells lacking AOX further evidences that a tight functional relationship exists between mitochondrial and chloroplastic processes of energy transduction, and that there could be a global redirection of bioenergetics towards photosynthesis to limit the harmful consequences (particularly oxidative stress) of mitochondrial deficiency. The observation that numerous N-responsive proteomic modifications are strongly attenuated (or even abolished) in response to Aox1 inactivation supports that AOX also exerts a more specific role as a central effector of the metabolic plasticity induced by modulating the N source in the growth medium. Our proteomic results tend notably to confirm that respiration (through AOX activity) and photosynthesis collaborate to provide nitrate reduction with electrons in mixotrophic condition and that acetate oxidation could be promoted to support AOX involvement in this context. [less ▲]

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See detailThe path of the ureter
Bonnet, Pierre ULg

Conference (2014, April 14)

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See detailCentral Pelvic spaces: Limits, content & landmarks
Bonnet, Pierre ULg

Conference (2014, April 14)

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See detailPelvic anatomy, a constructive approach
Bonnet, Pierre ULg

Conference (2014, April 14)

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See detailAnterolateral inferior abdominal wall anatomy: nerves and vessels.
Bonnet, Pierre ULg

Conference (2014, April 14)

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See detailThe International Criminal Court as the Principal Authority for Defining the Boundaries of its own Human Rights Obligations
Deprez, Christophe ULg

Conference (2014, April 14)

This paper addresses the applicability of human rights standards to the activity of the International Criminal Court. It argues that, in practice, the Court itself is the key authority when it comes to ... [more ▼]

This paper addresses the applicability of human rights standards to the activity of the International Criminal Court. It argues that, in practice, the Court itself is the key authority when it comes to determining the content of its own human rights obligations. This paradox is due to the fact that the only two legal constructions on which the ICC can convincingly and practically be said to be bound by human rights law – i.e. those that are respectively based on general sources of international law and on the Court’s founding treaty – leave much discretion to the interpreter as to the content of the resulting duties. [less ▲]

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See detailWhat about Google Scholar when searching information in Human and Physical Geography?
Stirbu, Simona ULg

Conference (2014, April 12)

This study focuses on four bibliographic tools and aims to highlight what the use of the Google Scholar search engine can yield, in comparison with three commercial bibliographical databases: the well ... [more ▼]

This study focuses on four bibliographic tools and aims to highlight what the use of the Google Scholar search engine can yield, in comparison with three commercial bibliographical databases: the well known multidisciplinary database Web of Science (WoS); GeoRef, a specialized data base in geosciences; and FRANCIS, which includes international geographical bibliography. To identify the bibliographic references published yearly between the years 2005 to 2009, ten keywords placed between quotation marks have been searched through the title field of the search tool interfaces. On a monthly basis, from November 2010 to July 2011, an identical process was repeated to get some information on the repeatability of the searches. Initially the whole set of results was analysed, and then the search results of two keywords were studied in more details. The results indicate that GS provides a high overlap with the search results of the other databases, but also yields numerous unique hits. Moreover, it seems that it is also able to find diverse types of literature, while the others are more specialized. [less ▲]

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See detailXenogeneic GVHD in NSG mice: focus on rapamycin
Ehx, Grégory ULg

Conference (2014, April 11)

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See detailLe pilotage par les chiffres de la politique sportive belge francophone
Zeimers, Géraldine ULg

Conference (2014, April 10)

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See detailFonctionnalisation des matières grasses alimentaires
Danthine, Sabine ULg; Blecker, Christophe ULg

Conference (2014, April 07)

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See detailElectromagnetic hypersensitivity and occupational exposure to electromagnetic fields (EMF)
Demaret, Isabelle ULg

Conference (2014, April 07)

Introduction Scientific publications on electromagnetic hypersensitivity began in the early 80' and were first related to video display terminals in the professional environment. Electromagnetic ... [more ▼]

Introduction Scientific publications on electromagnetic hypersensitivity began in the early 80' and were first related to video display terminals in the professional environment. Electromagnetic hypersensitivity is now more heterogeneous and complaints about electromagnetic fields (EMF) are often associated to mobile phone or wifi. Provocation studies did not find that persons claiming to have electromagnetic hypersensitivity were more able to detect EMF than others or that they displayed any special physiological changes when exposed to EMF. Since 1996, WHO defined this syndrome as Idiopathic Environmental Intolerance to ElectroMagnetic Fields (IEI-EMF), characterised by symptoms attributed to EMF. The diagnostic is made by the person itself. The symptoms are heterogeneous and are frequently encountered in the general population. Despite the lack of a proven causal relationship with EMF, these symptoms, and the anxiety related, can lead to important suffering. Some persons with IEI-EMF are even unable to work. IEI-EMF is classified among the functional somatic syndromes as other syndromes with no physiological basis (as multiple chemical sensitivity). Directive and IEI-EMF Studies showed that persons who feel more stressed in their professional environment and are less satisfied with their work are more prone to IEI-EMF. There are some elements in the directive that could frighten these persons: the directive does not consider long term effects; the limit values can be exceeded temporarily and a worker must be informed that he can have transient symptoms. Discussion Persons with IEI-EMF are afraid of adverse health effects and often think that these effects are not taken into account by official agency. For them, everything that can aggravate their fears will be difficult to handle. [less ▲]

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See detailEffet des conditions d'extraction sur la composition et les activités antioxydantes des ulvanes de l'algue Ulva lactucas
Yaich, Hela; Garna, Haikel; Paquot, Michel ULg et al

Conference (2014, April 07)

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See detailCaractérisation de la sève du palmier dattier
Makhlouf-Gafsi, Inès; Mokni-Ghribi, Abir; Attia, Hammadi et al

Conference (2014, April 07)

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See detailEnzymatic process for the fractionation of baker's yeast cell wall (saccharomyces cerevisiae)
Borchani, Chema; Fonteyn, Fabienne; Jamin, Guilhem et al

Conference (2014, April 07)

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See detailAccumulation lipidique par Yarrowia lipolytica: un nouvel outil d'observation
Bouchedja, Doria Naïla; Delvigne, Frank ULg; Boudjellal, Abdelghani et al

Conference (2014, April 06)

Detailed reference viewed: 34 (1 ULg)
See detailLe "Gate fever" : la cristallisation du temps carcéral
Englebert, Jérôme ULg

Conference (2014, April 05)

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See detailLiquidity Constraints and Global Imbalances
Artige, Lionel ULg; Cavenaile, Laurent

Conference (2014, April 05)

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See detailModélisation de l'attitude des médecins généralistes envers la prévention
Vanmeerbeek, Marc ULg; Giet, Didier ULg; Quittre, Valérie ULg et al

Conference (2014, April 05)

Objectifs En Belgique, la mise en œuvre des procédures préventives reste insuffisante et inéquitable dans plusieurs domaines. Les médecins généralistes (MG) sont-ils désireux de participer à ... [more ▼]

Objectifs En Belgique, la mise en œuvre des procédures préventives reste insuffisante et inéquitable dans plusieurs domaines. Les médecins généralistes (MG) sont-ils désireux de participer à l’amélioration de cette situation ? Méthode Un questionnaire postal a été envoyé à un échantillon aléatoire de 2.500 généralistes, répartis entre Flandre, Wallonie et Bruxelles. L’opinion des MG a été évaluée au moyen d’une échelle d’attitude. Cinq axes définis par une enquête qualitative préalable ont été explorés : vision globale de la santé, stratégies de prévention collectives, évaluation de pratique, collaboration interprofessionnelle et santé publique. Un consensus d’experts a défini les « meilleures » réponses aux échelles de Likert. Les résultats ont été soumis à une analyse factorielle exploratoire, puis à une analyse « Item Response Theory (IRT) » adaptée au traitement de réponses catégorielles (d’accord – pas d’accord). Résultats Les 457 réponses reçues ont été analysées pour modéliser l’attitude des MG ; trois dimensions ont été isolées : • Evaluation : positionne les MG selon leur souci à pratiquer une technique d’évaluation, à travailler par objectifs ou gérer leur base de données cliniques. • Responsabilité : attitude des MG qui se sentent responsables de la santé de leurs patients, ou qui organisent les conditions matérielles et relationnelles pouvant contribuer à son maintien. • Compétences professionnelles particulières : positionne les MG selon leur utilisation de plusieurs compétences « mineures » : acquisition et mise en pratique de l’information scientifique, délimitation des compétences entre praticiens et autorités de santé publique, délégation de tâches à des paramédicaux. Conclusion Une diffusion plus large et équitable des actes préventifs passe par la prise en compte de facteurs personnels et organisationnels propres aux MG. Leur distribution parmi les MG est probablement hétérogène, et leur degré d’acceptabilité variable. Une étude plus approfondie de la population des MG belges serait nécessaire. [less ▲]

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See detailEffet du traitement enzymatique sur la composition en polyphénols et sur le pouvoir antioxydant du sirop de dattes
Abbès, Fatma; Wissal, Kchaou; Blecker, Christophe ULg et al

Conference (2014, April 05)

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See detailCARACTERISATION MINERALOGIQUE, GEOCHIMIQUE ET GEOTECHNIQUE DES MATIERES PREMIERES UTILISEES DANS LE SITE POTIER D’AGAFAY (MARRAKECH, MAROC).
El Boudour El Idrissi, Hicham ULg; Daoudi, Lahcen; El Ouahabi, Meriam ULg et al

Conference (2014, April 04)

Le site potier d’Agafay est localisé à 20 km au Sud-Ouest de la ville de Marrakech. Le site comporte environ 240 artisans répartis sur 90 ateliers. Les principales pièces produites sont les gasriyas (i.e ... [more ▼]

Le site potier d’Agafay est localisé à 20 km au Sud-Ouest de la ville de Marrakech. Le site comporte environ 240 artisans répartis sur 90 ateliers. Les principales pièces produites sont les gasriyas (i.e., plats traditionnels de couscous et de modelage de pâtes de pains) et les briques traditionnelles. Les matières premières utilisées, brutes ou en mélange, sont issues des terres agricoles locales (Ag1 et Ag5) pour les gasriyas et des dépôts actuels de l’oued N’Fis (Ag7) pour les briques. Les défauts rencontrés dans la production diffèrent selon le type de produit confectionné et selon le type de matière première utilisée. La qualité des produits confectionnés à partir de Ag1 et Ag5 est altérée par la présence de grains de chaux qui gonflent après refroidissement des tessons cuits ; ce qui engendre des décollements dans les tessons et nuit à la qualité du produit final. Par ailleurs, les briques confectionnées à partir de Ag7 se caractérisent par une très grande variation de couleur, ce qui est du à une mauvaise cuisson et à une distribution non homogène de la chaleur à l’intérieur des fours traditionnels utilisés ; certaines briques sont totalement fondues. De plus les briques présentent généralement des torsions qui peuvent débuter après le cycle de séchage, mais qui s’amplifient après la cuisson. Notre étude vise à une caractérisation scientifique des différentes phases de fabrication afin de remédier à ces problèmes. Les résultats des analyses montrent que la composition chimique de l’ensemble des matières utilisée est surtout silico-alumineuse (55 à 61 % de SiO2 ; 16 à 20% d’Al2O3), la teneur en Fe2O3 se situe entre 6 et 8 %, celle de CaO ne dépasse pas 6% pour les pâtes des gasriyas et atteint 10 % pour les pâtes des briques. La teneur en carbonates varie de 5 à 14 %, alors que celle de la matière organique est comprise entre 5 et 7,5 %. L’indice de plasticité oscille entre 16 et 17,5. Pour des teneurs en eau proches de la limite de plasticité le degré de retrait au séchage des gasriyas est de l’ordre de 5 %, il est plus élevé pour les briques (8%) ce qui nécessite une plus grande maitrise du processus de séchage pour éviter que les pièces ne se tordent. La granulométrie des pâtes utilisées pour les gasriyas a montré une teneur moyenne de 50 % pour les argiles, 32 % pour les limons et 18 % pour les sables. Les briques comportent une proportion à peu prés équivalente des trois classes granulométriques. La minéralogie de l’ensemble des pâtes est formée de quartz (< 27%), plagioclase (13%), calcite (7 à 9%), dolomite (5%) et argile (50% pour Ag1 et Ag5, 34% pour Ag7). Le feldspath potassique est présent uniquement dans l’échantillon Ag7. Concernant la fraction argileuse, l’illite est dominante pour l’ensemble des pâtes ; elle est associée à des interstratifiés irréguliers 14c-14s (environ 13 %) pour la pâte des briques et à des smectites (environ 11 %) pour la pâte des gasriyas (Ag5). La mesure de la vitesse sonique a montré que les pièces formées par pression aboutissent à une porosité moindre que celle des pièces produites par boudinage. La densité des pièces produites reste semblable pour les cuissons à 950°C et 1050°C. Le plus bas degré de porosité ainsi que les plus grandes valeurs de résistance mécanique à la compression ont été enregistrés sur les pièces cuites à 1050 °C. Les contraintes maximales atteintes se situent entre 51 et 59 MPa pour les gasriyas et 24,5 MPa pour les briques. Quant à la résistance mécanique à la flexion, elle varie entre 17,4 et 20,3 N/mm² pour les gasriyas et 9,4 N/mm² pour les briques. L’analyse DRX des pièces cuites à 1050 °C a montré la disparition totale des carbonates et des argiles à cette température, accompagnée de l’apparition de la géhelénite, cristobalite, anorthoclase, diopside, spinelle et hématite. A l’issue de cette étude, nous recommandons un tamisage humide à 1 mm pour réduire l’effet des grains de chaux, un cycle de séchage plus adéquat, une cuisson par palier jusqu’à 1050°C et l’utilisation de fours qui garantissent une meilleure distribution de la chaleur. [less ▲]

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See detailRapports de forces et conflits : « la question balkanique »
Lika, Liridon ULg

Conference (2014, April 04)

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See detailUse of on-line flow cytometry for the characterization of microbial stress dynamics during the bioprocess
Brognaux, Alison ULg; Han, Shanshan; Sorensen, Soren et al

Conference (2014, April 03)

Microbial cell population heterogeneity is now recognized as a major source of issues for the development and optimization of bioprocesses. Flow cytometry is a very powerful tool for the follow up of ... [more ▼]

Microbial cell population heterogeneity is now recognized as a major source of issues for the development and optimization of bioprocesses. Flow cytometry is a very powerful tool for the follow up of physiological properties of microbial cells in process-related conditions at the single cell level, and can be used to study the dynamics of segregation directly in bioreactors. In this context, specific interfaces have been developed in order to connect flow cytometer (FC) directly on bioreactor for automated analyses. In this work, we propose a simplified version of such interface and demonstrated its usefulness for multiplexed experiments. This automated FC system has been tested for the follow up of the dynamics of an E. coli pfis::gfpAAV fluorescent bio-reporter and its PI uptake, correlated with membrane permeability. This bioreporter is composed of a fis promoter, a growth dependent promoter-indicator of the nutrient status of cells, fused to a gene expressing an unstable variant of GFP. The results obtained showed that the dynamics of the GFP synthesis is complex and can be attributed to a complex set of biological parameters. Segregation in the membrane permeability has been noticed. This work demonstrates that a simplified version of on-line FC can be used at the process level for the investigation of the dynamics of complex physiological mechanisms. [less ▲]

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See detailCaractérisation minéralogique, géochimique et géotechnique des matières premières utilisées en poterie dans le site d’Agafay, Marrakech, Maroc.
El Boudour El Idrissi, Hicham; Daoudi, Lahcen; El Ouahabi, Meriam ULg et al

Conference (2014, April 03)

Le site potier d’Agafay est localisé à 20 km au S-W de la ville de Marrakech, à l’ouest de l’oued N’Fis. L’activité potière y a débuté par transfert du savoir-faire à partir du village de Tamsloht vers ... [more ▼]

Le site potier d’Agafay est localisé à 20 km au S-W de la ville de Marrakech, à l’ouest de l’oued N’Fis. L’activité potière y a débuté par transfert du savoir-faire à partir du village de Tamsloht vers 1940 apr. J.-C. Le site comporte environ 90 ateliers où sont actifs 240 artisans. Les principales pièces produites sont les gasriyas (i.e., plats traditionnels de couscous et de modelage de pâtes de pains) et les briques des grandes murailles traditionnelles. Les matières premières utilisées, brutes ou en mélange, sont issues des terres agricoles locales (Ag1 et Ag5) pour les gasriyas et des dépôts actuels du oued N’Fis (Ag7) pour les briques. Les problématiques rencontrées dans ce site concernent les deux types de produits, gasriyas et briques. Dans le premier cas, des grains de la chaux gonflent dans les pièces après le contact prolongé des pièces produites avec l’air. Ce gonflement engendre des décollements dans les tessons et nuit à la qualité du produit final. Dans le deuxième cas, la distribution non homogène de la chaleur à l’intérieur des fours traditionnels utilisés engendre une très grande variation de couleur dans les briques, elles sont généralement tordues et certaines fondent totalement. Notre projet vise à une caractérisation scientifique des différentes phases de fabrication afin de remédier à ces problèmes. Les résultats montrent que la composition chimique est surtout silico-alumineuse (55 à 61 % de SiO2 ; 16 à 20% d’Al2O3), la teneur en Fe2O3 se situe entre 6 et 8 %, celle de CaO ne dépasse pas 6% pour les pâtes des gasriyas et atteint 10 % pour les pâtes des briques. La teneur en carbonates mesurée par le calcimètre de Bernard varie entre 5 et 14 %. La teneur en matière organique varie entre 5 et 7,5 %. L’indice de plasticité oscille entre 16 et 17,5. Pour des teneurs en eau proches de la limite de plasticité le degré de retrait au séchage des gasriyas est de l’ordre de 5 %, il est plus élevé pour les briques (8%) ce qui nécessite une plus grande maitrise du processus de séchage pour éviter que les pièces ne se tordent pas. La granulométrie des pâtes utilisées pour les gasriyas a montré une teneur moyenne de 50 % pour les argiles, 32 % pour les limons et 18 % pour les sables. Les briques comportent une proportion égale des trois classes granulométriques. La minéralogie de l’ensemble des pâtes est formée de quartz (< 27%), plagioclase (13%), calcite (7 à 9%), dolomite (5%) et argile (50%, 34% et 34% pour Ag1, Ag5 et Ag7, respectivement). Le feldspath potassique est présent uniquement dans l’échantillon Ag7. Concernant la fraction argileuse, elle est surtout constituée d’illite pour l’ensemble des pâtes, associée à des interstratifiés irréguliers 14c-14s (13 %) pour la pâte des briques, et une teneur de 11 % de smectite pour la pâte des gasriyas (Ag5). La mesure de la vitesse sonique a montré que les pièces formées par pression aboutissent à une porosité moindre que celle des pièces produites par boudinage. La densité des pièces produites reste semblable pour les cuissons à 950°C et 1050°C. Le plus bas degré de porosité ainsi que les plus grandes valeurs de résistance mécanique à la compression ont été enregistrés sur les pièces cuites à 1050 °C. Les contraintes maximales atteintes se situent entre 51 et 59 MPa pour les gasriyas et 24,5 MPa pour les briques. Quant à la résistance mécanique à la flexion, elle varie entre 17,4 et 20,3 N/mm² pour les gasriyas et 9,4 N/mm² pour les briques. L’analyse DRX des pièces cuites à 1050 °C a montré la disparition totale des carbonates et des argiles à cette température, accompagnée de l’apparition de la géhelénite, cristobalite, anorthoclase, diopside, spinelle et hématite. A l’issue de cette étude, nous recommandons un tamisage humide à 1 mm pour réduire l’effet des gros grains de la chaux, une cuisson par palier jusqu’à 1050°C est également nécessaire pour comprendre les transformations des phases minéralogiques et vitreuses. Finalement, l’utilisation des fours équipés d’une sonde pour garantir une meilleure distribution de la chaleur. [less ▲]

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See detailBayesian inference of a dynamic vegetation model for grassland
Minet, Julien ULg; Laloy, Eric; Tychon, Bernard ULg et al

Conference (2014, April 02)

As a part of the MACSUR task L2.4, we probabilistically calibrated the CARAIB dynamic vegetation model by Markov chain Monte Carlo (MCMC) simulation with the DREAMZS sampler.. CARAIB is a mechanistic ... [more ▼]

As a part of the MACSUR task L2.4, we probabilistically calibrated the CARAIB dynamic vegetation model by Markov chain Monte Carlo (MCMC) simulation with the DREAMZS sampler.. CARAIB is a mechanistic model that calculates the carbon assimilation of the vegetation as a function of the soil and climatic conditions, and can thus be used for simulating grassland production under cutting or grazing management. Bayesian model inversion was performed at 4 grassland sites across Europe: Oensingen, CH; Grillenburg, DE; Laqueuille, FR and Monte-Bodone, IT. Four daily measured variables from these sites: the Gross Primary Productivity (GPP), Net Ecosystem Exchange (NEE), Evapotranspiration (ET) and Soil Water Content (SWC) were used to sample 10 parameters related to rooting depth, stomatal conductance, specific leaf area, carbon-nitrogen ratio and water stresses. The maximized likelihood function therefore involved four objectives, whereas the applied Bayesian framework allowed for assessing the so called parameter posterior probability density function (pdf), which quantifies model parameter uncertainty caused by measurement and model errors. Sampling trials were performed using merged data from all sites (all-sites-sampling) and for each site (site-specific sampling) separately. The derived posterior parameter pdfs from the all-sites sampling and site-specific sampling runs showed differences in relation with the specificities of each site. Analysis of these distributions also revealed model sensitivity to parameters conditioned on the measured data, as well as parameter correlations. [less ▲]

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See detailFirst evidence of a volatile sex pheromone in the invasive Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae)
Fassotte, Bérénice ULg; Fischer, Christophe ULg; Durieux, Delphine ULg et al

Conference (2014, April 02)

Data about sex pheromones, or any semiochemicals that play a role in Coccinellid mating, remain limited. Since years, various studies and behavioral observations have hypothesized that such molecules are ... [more ▼]

Data about sex pheromones, or any semiochemicals that play a role in Coccinellid mating, remain limited. Since years, various studies and behavioral observations have hypothesized that such molecules are involved in sexual communication of ladybeetles. In this study, we collected volatile organic compounds released by virgin females of the multicolored Asian ladybeetle, Harmonia axyridis (Pallas), which were either allowed or not allowed to feed on aphids. In the presence of aphids, virgin females exhibited “calling behavior”, which has been associated with the emission of a sex pheromone in several Coleoptera species. Bioassays showed that these females released a blend of volatile compounds that is involved in the attraction of males. Gas Chromatography-Mass Spectrometry analyses highlighted specific volatile cues emanating from females, whereas males did not produce these compounds. Five components were identified: (–)-β-caryophyllene, β elemene, methyl-eugenol, α humulene, and α bulnesene. All compounds were produced after virgin females were fed aphids, and their quantity increased across the experimental period. The results confirm that female H. axyridis produce a volatile sex pheromone. Therefore, this study provides important biological information that could promote the development of efficient pest control management methods to manipulate the movements of this invasive ladybeetle, and to reduce its negative impacts on biodiversity. [less ▲]

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