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See detailEvaluation of geochemical determinism of trace elements in forest soils at regional scales. Lessons from the Permanent Forest Condition Survey.
Colinet, Gilles ULg; Baize, Denis; Lacroix, Daniel et al

Conference (2006)

The natural concentration of some elements in soil varies regionally according to lithology and locally with site-specific soil forming conditions such as relief or vegetation characteristics. Knowledge ... [more ▼]

The natural concentration of some elements in soil varies regionally according to lithology and locally with site-specific soil forming conditions such as relief or vegetation characteristics. Knowledge of the natural total concentrations of trace metals is now considered as prerequisite for the detection and assesment of anthropogenic contaminations. The Permanent Forest Inventory is a programme financed by the Ministry of the Walloon Region which aims at assessing and monitoring the forest condition in Southern Belgium. A part of this programme is dedicated to the implementation of a soil quality monitoring network. The observation plots are located at the intersection of a regular grid. Ten percent of the forest plots are planned to be sampled each year, which theorically supposes a time-frequency of 10 years for the monitoring considerations. Up to now, three field campaigns have been completed and 245 soil samples analyzed. Once a plot precisely located on the field, soil is sampled by mixing twenty 20cm-deep cores taken at the perimeter of a 10m large circle. Environmental observations complete the field work. These concern the physical environment, the soil morphology and the vegetation characteristics. The following parameters are measured in the laboratory: total organic carbon, total nitrogen, pHwater, pHKCl, exchangeable acidity and aluminium, cationic exchangeable capacity, NH4Cl-exctractible cations, total, mineral, and exchangeable P, and aqua-regia extractible concentrations of Ca, Mg, K, Al, Fe, Cr, Ni, Mn, Zn, Cu, Pb, Co, and Cd. Statistical analysis were then performed on the results in order to identify the driving factors of the soil properties, especially the geochemical determinism. Relationships between parameters and between parameters and field observations were thus investigated. Then the relevance of some classifications to differenciate the soil properties was evaluated and finally the spatial structure of the parameters was compared to the geographical distribution patterns of lithology, soil associations, or ecological territories. Although some diversity can be found among the soil series in this survey, soils developped from shales and/or sandstones are largely dominant. The first results therefore show a large extreme-based variability and moderate variation coefficients. The exchangeable cations and carbonate–sensitive parameters are the most variable. Frequency distributions are often largely skewed. Exchangeable cations appear to be more closely linked to acidity status than organic content while pseudo-total concentrations show rather good linear relationships between each other, to the exception of Pb and Cd. Both elements seem linked to specific lithologies, the presence of limestone for Pb, some clay-rich parent material or limestone for Cd. Among the soil characteristics, the nature and the abundance of the coarse fragments associated to the fine earth is the most differenciating criteria for pseudo-total content. Finally, there are clear convergences between spatial distributions of most of the elements and lithology or small natural regions. [less ▲]

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See detailLogement et gestion du foncier
Dogot, Thomas ULg

Article for general public (2006)

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See detailOrbitofrontal dysfunction related to both apathy and disinhibition in frontotemporal dementia
Peters, Frederic; Perani, Daniela; Herholz, Karl et al

in Dementia & Geriatric Cognitive Disorders (2006), 21(5-6), 373-379

Orbitofrontal metabolic impairment is characteristic of the frontal variant of frontotemporal dementia (fv-FTD), as are early changes in emotional and social conduct. Two main types of behavioral ... [more ▼]

Orbitofrontal metabolic impairment is characteristic of the frontal variant of frontotemporal dementia (fv-FTD), as are early changes in emotional and social conduct. Two main types of behavioral disturbances have been distinguished in fv-FTD patients: apathetic and disinhibited manifestations. In this study, we searched for relationships between brain metabolism and presence of apathetic or disinhibited behavior. Metabolic activity and behavioral data were collected in 41 fv-FTD patients from European PET centers. A conjunction analysis of the PET data showed an expected impairment of metabolic activity in the anterior cingulate, ventromedial and orbital prefrontal cortex, the dorsolateral prefrontal cortex and the left anterior insula in fv-FTD subjects compared to matched controls. A correlation was observed between disinhibition scores on the Neuropsychiatric Inventory scale and a cluster of voxels located in the posterior orbitofrontal cortex ( 6, 28, - 24). Comparison of brain activity between apathetic and nonapathetic fv-FTD patients from two centers also revealed a specific involvement of the posterior orbitofrontal cortex in apathetic subjects ( 4, 22, - 22). The results confirm that the main cerebral metabolic impairment in fv-FTD patients affects areas specializing in emotional evaluation and demonstrate that decreased orbitofrontal activity is related to both disinhibited and apathetic syndromes in fv-FTD. Copyright (C) 2006 S. Karger AG, Basel. [less ▲]

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See detailLe catalogue de l’exposition Dis-moi (+) : une invitation au dialogue
Bawin, Julie ULg

in Art Même : Chronique des Arts Plastiques de la Communauté française de Belgique (2006), (31), 46-47

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See detailLuc Grossen, une figure de l’art engagé
Bawin, Julie ULg

in Art Même : Chronique des Arts Plastiques de la Communauté française de Belgique (2006), (30), 33

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See detailLos 'sin voz' y los intelectuales en México. Reflexiones sobre algunos ensayos de Mariano Azuela, Octavio Paz y el EZLN.
Vanden Berghe, Kristine ULg

in Latinoamérica. Revista de estudios latinoamericanos. (2006), 42(1), 131-152

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See detailThe Critical Neighbourhood Range for Asymptotic Overlay Connectivity in Ad Hoc Networks
Calomme, Sandrine; Leduc, Guy ULg

in Ad Hoc & Sensor Wireless Networks (2006), 2(2), 169-187

We first motivate the use of ad hoc overlays. In particular, we argue that overlay routing could play a role in the spreading of ad hoc networks. We then define a simple criterion for neighbourhood: two ... [more ▼]

We first motivate the use of ad hoc overlays. In particular, we argue that overlay routing could play a role in the spreading of ad hoc networks. We then define a simple criterion for neighbourhood: two overlay nodes are neighbours if and only if there exists a path between them of at most R hops, and R is called the (overlay) neighbourhood range. A small R may result in a disconnected overlay, while an unnecessarily large R would generate extra control traffic. We are interested in the minimum R ensuring overlay connectivity, the so-called critical R. We study conditions on R to achieve asymptotic connectivity of the overlay almost surely, i.e. connectivity with probability 1 when the number of nodes in the underlying ad hoc network tends to infinity (so-called dense networks) or when the size of the field tends to infinity (socalled sparse networks), under the hypothesis that the underlying ad hoc network is itself asymptotically almost surely connected. For dense networks, we derive a necessary and sufficient condition on R, and for sparse networks we derive distinct necessary and sufficient conditions that are however asymptotically tight. These conditions, though asymptotic, shed some light on the relation linking the critical R to the number of nodes n, the field size the radio transmission range r and the overlay density D (i.e., the proportion of overlay nodes). These conditions can be considered as approximations when the number of nodes (resp. the field) is large enough. Since r is considered as a function of n or l , we are able to study the impact of topology control mechanisms, by showing how the shape of this function impacts the critical R. [less ▲]

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See detailProteome variations of the Myzus persicae aphid according to host plant change.
Francis, Frédéric ULg; GERKENS, P.; Harmel, Nicolas ULg et al

in Insect Biochemistry and Molecular Biology (2006), 36(3), 219-227

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See detailCompte rendu de David BRADSHAW, "Aristotle East and West. Metaphysics and the Division of Christendom"
Gavray, Marc-Antoine ULg

in Antiquité Classique : Revue Interuniversitaire d'Etudes Classiques (2006), 75

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See detailCompte rendu deLuciana ROMERI, "Philosophie entre mots et mets. Plutarque, Lucien et Athénée à la table de Platon"
Gavray, Marc-Antoine ULg

in Antiquité Classique : Revue Interuniversitaire d'Etudes Classiques (2006), 75

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See detailLa forme du poème : effets analytiques, effets synthétiques
Purnelle, Gérald ULg

in Delville, Michel; Belloi, Livio (Eds.) L'oeuvre en morceaux: Esthétiques de la mosaïque (2006)

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See detailAchromatic optical vortex coronagraph with subwavelength gratings
Mawet, Dimitri ULg; Riaud, Pierre ULg; Baudrand, J. et al

in Proceedings of the Coronagraph Workshop (2006)

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See detailLe “vers de prose” : vers et prose ? entre vers et prose ? (ni vers ni prose ?)
Purnelle, Gérald ULg

in Formes Poétiques Contemporaines (2006), 4

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See detailInfluence of experimental parameters on properties and microstructure of the steel X210CrW12 in the semi-solid state
Fraipont, Céline; Puettgen, Wolfgang; Bleck, Wolfgang et al

in Solid State Phenomena (2006), 116-117

This paper deals with the examination of the steel grade X210CrW12 and its suitability for Thixoforming. In the semi-solid state, the microstructure of this steel consists of a homogeneous distribution of ... [more ▼]

This paper deals with the examination of the steel grade X210CrW12 and its suitability for Thixoforming. In the semi-solid state, the microstructure of this steel consists of a homogeneous distribution of globular particles surrounded by liquid. Additionally, carbides are stabile up to fraction liquid contents of approximately 40%. After quenching, this steel reveals a globular austenitic microstructure with eutectic (former liquid phase) at the grain boundaries. Compression tests permit to determine the influence of different process parameters on the properties and the material behaviour in the semi-solid state. Their influence on the microstructure was investigated but not yet highlighted. Further investigations on this steel allow a fine-tuning to establish optimal process windows of the different thixoforming- and rheoforming-routes. [less ▲]

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See detailThe power of hybrid acceleration
Boigelot, Bernard ULg; Herbreteau, Frédéric

in Lecture Notes in Computer Science (2006), 4144

This paper addresses the problem of computing symbolically the set of reachable configurations of a linear hybrid automaton. A solution proposed in earlier work consists in exploring the reachable ... [more ▼]

This paper addresses the problem of computing symbolically the set of reachable configurations of a linear hybrid automaton. A solution proposed in earlier work consists in exploring the reachable configurations using an acceleration operator for computing the iterated effect of selected control cycles. Unfortunately, this method imposes a periodicity requirement on the data transformations labeling these cycles, that is not always satisfied in practice. This happens in particular with the important subclass of timed automata, even though it is known that the paths of such automata have a periodic behavior. The goal of this paper is to broaden substantially the applicability of hybrid acceleration. This is done by introducing powerful reduction rules, aimed at translating hybrid data transformations into equivalent ones that satisfy the periodicity criterion. In particular, we show that these rules always succeed in the case of timed automata. This makes it possible to compute an exact symbolic representation of the set of reachable configurations of a linear hybrid automaton, with a guarantee of termination over the subclass of timed automata. Compared to other known solutions to this problem, our method is simpler, and applicable to a much larger class of systems. [less ▲]

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See detailCompte rendu de l'ouvrage de G. Michaud et É. Nardout-Lafarge, Constructions de la modernité au Québec
Provenzano, François ULg

in Mondes francophones.com : revue mondiale des francophonies (2006)

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See detailHippocampal response at training promotes insight after sleep
Darsaud, Annabelle; Balteau, Evelyne ULg; Desseilles, Martin ULg et al

in NeuroImage (2006), 31(Suppl. 1),

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See detailLa langue des vers : le cas des e post-toniques entravés
Purnelle, Gérald ULg

in Viprey, Jean-Marie (Ed.) JADT 06. Actes des 8es Journées internationales d’Analyse statistique des Données Textuelles (2006)

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