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See detailCharacterization of the placoderm (Gnathostomata) assemblage from the tetrapod-bearing locality of Strud (Belgium, Upper Famennian)
Olive, Sébastien ULg; Clément, Gaël; Daeschler, Edward et al

in Palaeontology (in press)

The placoderm fauna of the late Famennian tetrapod-bearing locality of Strud, Belgium, is studied on the basis of historical and newly collected material. It includes the previously described antiarch ... [more ▼]

The placoderm fauna of the late Famennian tetrapod-bearing locality of Strud, Belgium, is studied on the basis of historical and newly collected material. It includes the previously described antiarch Grossilepis rikiki, the groenlandaspidid Turrisaspis strudensis sp. nov. and the actinolepidoideid Phyllolepis undulata. P. undulata is thoroughly described and joins the list of the valid Phyllolepis species confidently diagnosed. A morphometrical analysis performed on the centronuchal and anterior ventrolateral plates of the Phyllolepis material demonstrates that there is only one species of Phyllolepis in Belgium (thus, Phyllolepis konincki becomes a junior synonym of P. undulata), that P. rossimontina (Pennsylvania) is a synonym of P. undulata and that the unity of the genus Phyllolepis is strongly supported, although the characterization of several species within this genus is blurred. The strong resemblance between the faunal compositions in Strud and Red Hill (Pennsylvania, USA) suggests important faunal exchanges between these regions of the Euramerica landmass. [less ▲]

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See detailStratigraphy and depositional environments of the Late Famennian (Late Devonian) of Southern Belgium and characterization of the Strud locality
Denayer, Julien ULg; Prestianni, Cyrille; Gueriau, Pierre et al

in Geological Magazine (in press)

The Famennian (Upper Devonian, c. 372 to 359 Ma) strata of Belgium have recently received much attention after the discoveries of early tetrapod remains and outstandingly preserved continental arthropods ... [more ▼]

The Famennian (Upper Devonian, c. 372 to 359 Ma) strata of Belgium have recently received much attention after the discoveries of early tetrapod remains and outstandingly preserved continental arthropods. The Strud locality has yielded a diverse flora and fauna including seed-plants, tetrapods, various placoderm, actinopterygian, acanthodian and sarcopterygian fishes, crustaceans (anostracans, notostracans, conchostracans and decapods) and a putative complete insect. This fossil assemblage is one of the oldest continental – probably fresh-water – ecosystems with a considerable vertebrate and invertebrate diversity. The study of the palaeoenvironment of the Strud locality is crucial because it records one of the earliest and most important phases of tetrapod evolution that took place after their emergence but before their terrestrialization. It raises the question of environmental and ecological conditions for the Devonian aquatic ecosystem and the selection pressures occurring at the onset of tetrapod terrestrialization. The present study characterized the fluvial facies of the Upper Famennian sedimentary rocks of Strud and the surrounding areas. The exceptional preservation of arthropods and plants in the main fossiliferous layers is explained by rapid burial in the fine-grained sediment of the quiet and confined flood plain environment. Newly investigated fossiliferous sections in the Meuse–Samson area led to the description and correlation of key sections (Strud, Wierde and Jausse sections, complemented by the less continuous Haltinne, Huy and Coutisse sections). Moreover, the investigated sections allowed a review of the age of the fossiliferous horizon, which is now definitely considered to be Late Famennian in age. [less ▲]

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See detailLa resiliencia comunitaria en el centro de la mitigacion de amenazas naturales: un breve estado del arte
Schmitz, Serge ULg

in Hermesse, Julie; Schmitz, Serge; Servais, Olivier (Eds.) et al Ordenamiento territorial en la prevención de desastres (in press)

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See detailExperimental and computational micro–mechanical investigations of compressive properties of polypropylene/multi–walled carbon nanotubes nanocomposite foams
Wan, Fangyi; Tran, Minh Phuong; Leblanc, Christophe ULg et al

in Mechanics of Materials (in press)

The compressive behavior of nanocomposite foams is studied by both experimental and computational micro-mechanics approaches with the aim of providing an efficient computational model for this kind of ... [more ▼]

The compressive behavior of nanocomposite foams is studied by both experimental and computational micro-mechanics approaches with the aim of providing an efficient computational model for this kind of material. The nanocomposites based on polypropylene (PP) and different contents of multi-walled carbon nanotubes (CNTs) are prepared by melt mixing method. The nanocomposite samples are foamed using super-critical carbon dioxide (ScCO2) as blowing agent at different soaking temperatures. The influence of this foaming parameter on the morphological characteristics of the foam micro-structure is discussed. Differential Scanning Calorimetry (DSC) measurements are used to quantify the crystallinity degree of both nanocomposites and foams showing that the crystallinity degree is reduced after the foaming process. This modification leads to mechanical properties of the foam cell walls that are different from the raw nanocomposite PP/CNTs material. Three--point bending tests are performed on the latter to measure the flexural modulus in terms of the crystallinity degree. Uniaxial compression tests are then performed on the foamed samples under quasi-static conditions in order to extract the macro-scale compressive response. Next, a two-level multi-scale approach is developed to model the behavior of the foamed nanocomposite material. On the one hand, the micro-mechanical properties of nanocomposite PP/CNTs cell walls are evaluated from a theoretical homogenization model accounting for the micro-structure of the semi-crystalline PP, for the degree of crystallinity, and for the CNT volume fraction. The applicability of this theoretical model is demonstrated via the comparison with experimental data from the described experimental measurements and from literature. On the other hand, the macroscopic behavior of the foamed material is evaluated using a computational micro-mechanics model using tetrakaidecahedron unit cells and periodic boundary conditions to estimate the homogenized properties. The unit cell is combined with several geometrical imperfections in order to capture the elastic collapse of the foamed material. The numerical results are compared to the experimental measurements and it is shown that the proposed unit cell computational micro-mechanics model can be used to estimate the homogenized behavior, including the linear and plateau regimes, of nanocomposite foams. [less ▲]

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See detailp-regularity of the p-adic valuation of the Fibonacci sequence
Medina, Luis; Rowland, Eric ULg

in Fibonacci Quarterly (The) (in press)

We show that the p-adic valuation of the sequence of Fibonacci numbers is a p-regular sequence for every prime p. For p≠2,5, we determine that the rank of this sequence is α(p)+1, where α(m) is the ... [more ▼]

We show that the p-adic valuation of the sequence of Fibonacci numbers is a p-regular sequence for every prime p. For p≠2,5, we determine that the rank of this sequence is α(p)+1, where α(m) is the restricted period length of the Fibonacci sequence modulo m. [less ▲]

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See detailComment la participation à une recherche contribue au développement professionnel : le cas des exemples à l’Université
Fossion, Gilles ULg; Faulx, Daniel ULg

in Recherches Qualitatives (in press)

La recherche scientifique constitue un des piliers centraux de l’activité universitaire. Nous nous sommes donc questionnés sur les apprentissages générés par celle-ci. Après avoir brièvement décrit les ... [more ▼]

La recherche scientifique constitue un des piliers centraux de l’activité universitaire. Nous nous sommes donc questionnés sur les apprentissages générés par celle-ci. Après avoir brièvement décrit les objectifs et enjeux de cette communication, nous proposons une présentation des objectifs et de la méthodologie de la recherche que nous avons menée au sein des Facultés de Psychologie et des Sciences de l’Éducation de l’Université de Liège. Nous poursuivons, enfin, par la mise en évidence de ses principaux résultats. Ces résultats se situent sur deux niveaux. D’une part, nous présentons les résultats inhérents à la recherche - relative aux impacts générés par la mobilisation de l’exemple au sein du discours pédagogique - et qui contribue à l’enrichissement du champ scientifique abordé. D’autre part, nous abordons les résultats qui permettent la mise en évidence de l’aspect formatif que revêt la participation à une recherche scientifique pour les acteurs. [less ▲]

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See detailCariteo
Amendola, Cristiano ULg

in Frare, Pierantonio; Langella, Giuseppe; Frasso, Giuseppe (Eds.) Dizionario Biblico della Letteratura Italiana (in press)

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See detailContribution of the Finite Volume Point Dilution Method for measurement of groundwater fluxes in a fractured aquifer
Jamin, Pierre ULg; Goderniaux, Pascal; Bour, Olivier et al

in Journal of Contaminant Hydrology (in press)

Measurement of groundwater fluxes is the basis of all hydrogeological study, from hydraulics characterization to the most advanced reactive transport modelling. Usual groundwater fluxes estimation with ... [more ▼]

Measurement of groundwater fluxes is the basis of all hydrogeological study, from hydraulics characterization to the most advanced reactive transport modelling. Usual groundwater fluxes estimation with Darcy’s law may lead to cumulated errors on spatial variability, especially in fractured aquifers where local direct measurement of groundwater fluxes becomes necessary. In the present study, both classical Point Dilution Method (PDM) and Finite Volume Point Dilution Method (FVPDM) are compared on the fractured crystalline aquifer of Ploemeur, France. The manipulation includes the first use of the FVPDM in a fractured aquifer using a double packer. This configuration limits the vertical extend of the tested zone to target a precise fracture zone of the aquifer. The result of this experiment is a continuous monitoring of groundwater fluxes that lasted for more than 4 days. Measurements of groundwater flow rate in the fracture (Qt) by PDM provide good estimates only if the mixing volume (Vw) (volume of water in which the tracer is mixed) is precisely known. Conversely, the FVPDM allows for an independent estimation of Vw and Qt, leading to better precision in case of complex experimental setup such as the one used. The precision of a PDM does not rely on the duration of the experiment while a FVPDM may require long experimental duration to guarantees a good precision. Classical PDM should then be used for rapid estimation of groundwater flux using simple experimental setup. On the other hand, the FVPDM is a more precise method that has a great potential for development but may require longer duration experiment to achieve a good precision if the groundwater fluxes investigated are low and/or the mixing volume is large. [less ▲]

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See detailDrying induced shrinkage of Boom Clay: an experimental investigation
Prime, Noémie; Levasseur, Séverine; Miny, Laurent et al

in Canadian Geotechnical Journal (in press)

Drying induced shrinkage of geomaterials may have a strong effect on geostructure stability and deformation. Settlement of foundations, fracture opening on slopes, roads, tunnel walls may be due to drying ... [more ▼]

Drying induced shrinkage of geomaterials may have a strong effect on geostructure stability and deformation. Settlement of foundations, fracture opening on slopes, roads, tunnel walls may be due to drying shrinkage. However, there is still a lack of knowledge concerning shrinkage evolution in time and shrinkage propagation within the material. In this study, the shrinkage of a specific clayey rock, Boom Clay, under drying conditions is experimentally investigated. This rock is a deep geological formation which is under study for high-level and long-life radioactive waste storage in Belgium. Two experimental campaigns are here presented. The first one, based on vapour equilibrium drying technique and completed by sample size manual measurement, aims to characterize the material shrinkage in balanced states. The second one, based on convective drying technique completed by shape monitoring using X-ray tomography, aims to analyse how shrinkage develops before reaching a steady state. Both approaches put in evidence the shrinkage anisotropy of this structurally bedded rock, with a ratio around 2 between the direction of maximum strains and the direction of minimum strains. However, the two drying techniques also provide complementary results, as the relation between the amount of shrinkage and the retention curve (for the uniform drying imposed with saline solutions) and the kinetics of shrinkage propagation inside the material (for the non-uniform drying imposed with air convection). [less ▲]

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See detailThe np- Control Charts with the Guaranteed In-Control Performance
Faraz, Alireza ULg; Heuchenne, Cédric ULg

E-print/Working paper (2016)

In this paper, we evaluate the in-control performance of np-control charts with estimated parameters. We then apply the bootstrap method to adjust the control charts’ limits to guarantee the desired in ... [more ▼]

In this paper, we evaluate the in-control performance of np-control charts with estimated parameters. We then apply the bootstrap method to adjust the control charts’ limits to guarantee the desired in-control average run length (ARL0) value in monitoring stage. The adjusted limits ensure that ARL0 would take a value greater than the desired value (say, B) with a certain specified probability, that is Pr⁡(ARL_0>B)=1-ρ. We finally provide users with tables which with practitioners do not need to do bootstrapping Phase I data set to obtain the control limit thresholds. [less ▲]

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See detailColère des agriculteurs, à qui la faute?
Habran, Maxime ULg

E-print/Working paper (2016)

Depuis le début de l’été, la colère gronde du côté des agriculteurs et pour cause, les prix du lait et de la viande ont atteint des seuils dangereusement bas. Que ce soit en France ou en Belgique, le ... [more ▼]

Depuis le début de l’été, la colère gronde du côté des agriculteurs et pour cause, les prix du lait et de la viande ont atteint des seuils dangereusement bas. Que ce soit en France ou en Belgique, le combat est le même. Les agriculteurs veulent des prix plus élevés pour la viande et pour le lait car actuellement ceux-ci sont inférieurs aux coûts de production. Cette note a pour objectif de répondre à trois questions : d’où vient la crise, quelles sont les solutions et les mesures prises sont-elles suffisantes ? [less ▲]

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See detailEVALUATION OF FISH EXPOSURE TO POP-LIKE (ORGANOTIN) COMPOUNDS IN SEPETIBA BAY (RIO DE JANEIRO STATE, BRAZIL) THROUGH HEPATIC TOTAL TIN CONCENTRATIONS
Paiva, TC; Schilithz, PF; Bisi, TL et al

in Organohalogen Compounds (2016, August)

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See detailPolitique agricole commune. Analyse transversale de la conditionnalité environnementale
Habran, Maxime ULg

Book published by Bruylant (2016)

Pierre angulaire de la construction européenne, la politique agricole commune (PAC) est à l’origine mise en place dans le but d’assurer l’autosuffisance alimentaire de la Communauté européenne. L’objectif ... [more ▼]

Pierre angulaire de la construction européenne, la politique agricole commune (PAC) est à l’origine mise en place dans le but d’assurer l’autosuffisance alimentaire de la Communauté européenne. L’objectif, rapidement atteint, laisse dans son sillage des stocks et excédents considérables ainsi que des dépenses communautaires importantes. Le mode de production agricole basé sur un modèle productiviste montre rapidement ses limites, obligeant les États membres à une réorientation de la PAC. Cette politique sera modifiée et réformée à de nombreuses reprises. La reconnaissance de la protection de l’environnement comme politique transversale contraint les États membres à l’adapter. D’une politique productiviste, elle devient attentive aux considérations environnementales, intégrant ces dernières dans chacune des réformes, allant même jusqu’à lier l’octroi de paiement au respect de règles essentiellement environnementales. Cet ouvrage présente la manière dont s’articule la relation entre les deux politiques autour de la notion de conditionnalité environnementale. À travers une étude minutieuse de chaque réforme de la PAC, une analyse de transversalité permet de saisir les enjeux et les motivations de l’intégration environnementale. [less ▲]

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See detailAn Exact Method for Designing Shewhart X ̅ and S2 Control Charts to Guarantee the In-Control Performance
Faraz, Alireza ULg; Heuchenne, Cédric ULg

in Journal of Quality Technology (2016)

The in-control performance of the Shewhart X ̅ and S2 control charts with estimated in-control parameters has been evaluated by a number of authors. Results indicate an unrealistically large amount of ... [more ▼]

The in-control performance of the Shewhart X ̅ and S2 control charts with estimated in-control parameters has been evaluated by a number of authors. Results indicate an unrealistically large amount of Phase I data is needed to have the desired in-control average run length (ARL) value in Phase II. To overcome this problem, it has been recommended that the control limits be adjusted based on a bootstrap method to guarantee that the in-control ARL is at least a specified value with a certain specified probability. In our paper we present simple formulas for the required control limits so that practitioners do not have to use the bootstrap method. An assumption of normality is required. The advantage of our proposed method is in its simplicity; there is no bootstrapping and the control chart constants do not depend on the Phase I sample data. [less ▲]

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See detailEspace, temps et angoisse psychotique : à propos d'un cas magistral
Englebert, Jérôme ULg

Scientific conference (2016, March 26)

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See detailSaint Genet et le dépassement de la situation : Création d’une clinique sartrienne
Englebert, Jérôme ULg

Scientific conference (2016, March 09)

Nous proposons de partir de Saint Genet : Comédien et Martyr (1952), monumentale psychobiographie de Sartre, pour évoquer une première lecture de la temporalité sartrienne et particulièrement des notions ... [more ▼]

Nous proposons de partir de Saint Genet : Comédien et Martyr (1952), monumentale psychobiographie de Sartre, pour évoquer une première lecture de la temporalité sartrienne et particulièrement des notions d’« instant » et de « conversion ». Le sujet clinique sur lequel s’appuiera notre propos et qui retiendra notre attention est l’incendiaire (dont on rappellera la différence avec le pyromane). Ensuite, nous convoquerons, et confondrons, L’esquisse d’une théorie des émotions (1933) et les Questions de Méthodes (1957). Ces deux points de repère nous permettront de reprendre le cas Genet et sa réaction à la lecture du volume que Sartre lui a consacré. D’importantes questions méthodologiques en psychologie clinique naîtront de ce développement et feront émerger une perspective « en double spirale » et la décisive question du corps. [less ▲]

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See detailMapping of riparian invasive species with supervised classification of Unmanned Aerial System (UAS) imagery
Michez, Adrien ULg; Piégay, Hervé; Lisein, Jonathan ULg et al

in International Journal of Applied Earth Observation and Geoinformation (2016), 44

Riparian zones are key landscape features, representing the interface between terrestrial and aquatic ecosystems. Although they have been influenced by human activities for centuries, their degradation ... [more ▼]

Riparian zones are key landscape features, representing the interface between terrestrial and aquatic ecosystems. Although they have been influenced by human activities for centuries, their degradation has increased during the 20th century. Concomitant with (or as consequences of) these disturbances, the invasion of exotic species has increased throughout the world’s riparian zones. In our study, we propose a easily reproducible methodological framework to map three riparian invasive taxa using Unmanned Aerial Systems (UAS) imagery: Impatiens glandulifera Royle, Heracleum mantegazzianum Sommier and Levier, and Japanese knotweed (Fallopia sachalinensis (F. Schmidt Petrop.), Fallopia japonica (Houtt.) and hybrids). Based on visible and near-infrared UAS orthophoto, we derived simple spectral and texture image metrics computed at various scales of image segmentation (10,30, 45, 60 using eCognition software). Supervised classification based on the random forests algorithm was used to identify the most relevant variable (or combination of variables) derived from UAS imagery for mapping riparian invasive plant species. The models were built using 20% of the dataset, the rest of the dataset being used as a test set (80%). Except for H. mantegazzianum, the best results in terms of global accuracy were achieved with the finest scale of analysis (segmentation scale parameter = 10). The best values of overall accuracies reached 72%, 68%, and 97% for I. glandulifera, Japanese knotweed, and H. mantegazzianum respectively. In terms of selected metrics, simple spectral metrics (layer mean / camera brightness) were the most used. Our results also confirm the added value of texture metrics (GLCM derivatives) for mapping riparian invasive species. The results obtained for I. glandulifera and Japanese knotweed do not reach sufficient accuracies for operational applications. However, the results achieved for H. mantegazzianum are encouraging. The high accuracies values combined to relatively light model-inputs needed (delineation of a few umbels) make our approach a serious contender as a cost-effective tool to improve the field management of H. mantegazzianum. [less ▲]

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See detailHistoire, géographie et esthétique : peut-on récapituler la psychologie clinique ?
Englebert, Jérôme ULg

Scientific conference (2016, January 23)

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See detailI grecismi in Gaio
Rochette, Bruno ULg

Conference (2016, January 11)

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See detailAre there synthetic a priori propositions ? The paradigmatic case of mathematics, from Kant to Frege and Peirce
Leclercq, Bruno ULg

in Petrov, Vesselin (Ed.) Mathematics in Philosophy (2016)

Bernard Bolzano notoriously rejected Immanuel Kant’s claim that arithmetic and geometry were grounded on synthetic a priori judgements based on pure intuition. According to Bolzano, only analysis of ... [more ▼]

Bernard Bolzano notoriously rejected Immanuel Kant’s claim that arithmetic and geometry were grounded on synthetic a priori judgements based on pure intuition. According to Bolzano, only analysis of concepts could ground the generality of mathematical statements and proofs; such a stand would later lead to logicism (from Frege to Carnap). Far from going in this way, however, Charles Sanders Peirce, who was one of the fathers of formal logic but also a great admirer of Kant, provided semiotic reasons to believe that diagrams do have a general meaning and that they can provide a knowledge which is both general and “ampliative”. Unlike mere logical analysis, diagrams (the analogon of Kant’s schemas) help to explore concepts by going somehow “outside of them” in such a way that new knowledge is gained. This provides new support to Kant’s notion of intuitive construction, which is supposed to be both deductive and inventive [less ▲]

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