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See detailLectotypification of the Famennian pre-ovule Condrusia rumex Stockmans, 1948
Prestianni, Cyrille ULg; Gerrienne, Philippe ULg

in Review of Palaeobotany and Palynology (2006), 142(3-4), 161-164

Condrusia rumex Stockmans 1948 occurs in several localities of the Belgian Evieux Formation (late Famennian, Upper Devonian). It consists of a hastate organ borne at the tip of "slender, dichotomizing ... [more ▼]

Condrusia rumex Stockmans 1948 occurs in several localities of the Belgian Evieux Formation (late Famennian, Upper Devonian). It consists of a hastate organ borne at the tip of "slender, dichotomizing" axes. Various interpretations have been given to this intriguing structure, ranging from a spore-bearing organ to a fern prothallus but recent investigations consider Condrusia to be an ovulate structures produced by early seed plants. The genus Condrusia includes 3 species: C rumex Stockmans, C. minor Stockmans and C. brevis Petrosjan. C rumex was described by Stockmans in 1948, who provided a diagnosis and illustrations, but failed to designate a holotype. We are currently reinvestigating the genus and we here designate and illustrate a lectotype for the genus and species C. rumex. (c) 2006 Elsevier B.V. All rights reserved. [less ▲]

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See detailThe in vitro influences of neurotensin on the motility characteristics of human U373 glioblastoma cells
Servotte, S.; Camby, I.; Debeir, O. et al

in Neuropathology & Applied Neurobiology (2006), 32(6), 575-584

Astrocytic tumours are associated with dismal prognoses due to their pronounced ability to diffusely invade the brain parenchyma. Various neuropeptides, including gastrin, are able to modulate tumour ... [more ▼]

Astrocytic tumours are associated with dismal prognoses due to their pronounced ability to diffusely invade the brain parenchyma. Various neuropeptides, including gastrin, are able to modulate tumour astrocyte migration. While neurotensin has been shown to influence the proliferation of glioma cells and the migratory ability of a large set of other cell types, its role in glioma cell migration has never been investigated. Neurotensin-induced modifications to the motility features of human U373 glioblastoma cells therefore constitute the topic of the present study. We evidenced that three subtypes of neurotensin receptors (NTR1, NTR2 and NTR3) are expressed in U373 glioblastoma cells, at least as far as their mRNAs are concerned. Treating U373 tumour cells with 10 nM neurotensin markedly modified the morphological patterns of these cells and also profoundly altered the organization of their actin cytoskeletons. Pull-down assays revealed that neurotensin induced the activation in U373 cells of both Rac1 and Cdc42 but not RhoA. Scratch wound assays evidenced that neurotensin (0.1 and 10 nM) very significantly inhibited wound colonization by U373 cells cultured in the absence of serum. In addition, quantitative phase-contrast videomicroscopy analyses showed that neurotensin decreases the motility levels of U373 glioblastoma cells when these cells are cultured on plastic. In sharp contrast, neurotensin stimulates the motility of U373 cells when they are cultured on laminin, which is a pro-adhesive extracellular matrix component ubiquitously secreted by glioma cells. Our data thus strongly suggest that, in addition to gastrin, neurotensin is a neuropeptide capable of modulating tumour astrocyte migration into the brain parenchyma. [less ▲]

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See detailDeployment of an Algorithm for Large-Scale Topology Discovery
Donnet, Benoît ULg; Raoult, Philippe; Friedman, Timur et al

in IEEE Journal on Selected Areas In Communications (2006), 24(12), 2210--2220

Topology discovery systems are starting to be in- troduced in the form of easily and widely deployed software. Unfortunately, the research community has not examined the problem of how to perform such ... [more ▼]

Topology discovery systems are starting to be in- troduced in the form of easily and widely deployed software. Unfortunately, the research community has not examined the problem of how to perform such measurements efficiently and in a network-friendly manner. This paper describes several contributions towards that end. These were first presented in the proceedings of ACM SIGMETRICS 2005. We show that standard topology discovery methods (e.g., skitter) are quite inefficient, repeatedly probing the same interfaces. This is a concern, because when scaled up, such methods will generate so much traffic that they will begin to resemble DDoS attacks. We propose two metrics focusing on redundancy in probing and show that both are important. We also propose and evaluate Doubletree, an algorithm that strongly reduces redundancy while maintaining nearly the same level of node and link coverage. The key ideas are to exploit the tree-like structure of routes to and from a single point in order to guide when to stop probing, and to probe each path by starting near its midpoint. Following the SIGMETRICS work, we implemented Doubletree, and deployed it in a real network environment. This paper describes that implementation, as well as preliminary favorable results. [less ▲]

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See detailSound field modeling in architectural acoustics using a diffusion equation
Picaut, Judicaël; Valeau, Vincent; Billon, Alexis ULg et al

Conference (2006, December)

A numerical approach is proposed to model the reverberated sound field in rooms. The model is based on the numerical implementation of a diffusion model enabling spatial variations of the sound energy ... [more ▼]

A numerical approach is proposed to model the reverberated sound field in rooms. The model is based on the numerical implementation of a diffusion model enabling spatial variations of the sound energy within a room, unlike the statistical theory. The proposed method allows to take into account most of complex phenomena encountered in room acoustics, like mixed reflections on walls (diffuse and specular), low and high absorption on walls, atmospheric attenuation, fitted zones. Moreover, the model can be applied to complex geometries, like multiple coupled rooms of different sizes. In this paper, the model and its numerical implementation are first detailed. Then, an application is proposed for a complex geometry defined by multiple coupled rooms with fitting objects, including low and high absorption on walls, in terms of sound level and reverberation times. The main interest of the model is that such approach requires less computational time in comparison with common approaches like ray-tracing simulations. [less ▲]

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See detailAn exceptional specimen of the early land plant Cooksonia paranensis, and a hypothesis on the life cycle of the earliest eutracheophytes
Gerrienne, Philippe ULg; Dilcher, D. L.; Bergamaschi, S. et al

in Review of Palaeobotany and Palynology (2006), 142(3-4), 123-130

An exceptionally large specimen of the early land plant Cooksonia paranensis Gerrienne et al. has been discovered from the type locality (Jackson de Figueiredo, Parana Basin, Brazil; early Lochkovian ... [more ▼]

An exceptionally large specimen of the early land plant Cooksonia paranensis Gerrienne et al. has been discovered from the type locality (Jackson de Figueiredo, Parana Basin, Brazil; early Lochkovian, Early Devonian). This nearly complete specimen consists of five dichotomous axes attached at their base to a small thalloid(?) structure. Each terminal axis segment ends in an expanded, cup-like, empty tip. Three interpretations of the specimen are proposed. (1) The whole specimen is a gametophyte of the Sciadopkyton-type, with a central area from which five axes depart; under this interpretation, the terminal cups are gametangiophores. (2) The basal structure represents the remains of a rhizome bearing five upright aerial axes, in which case the whole plant is a sporophyte. (3; our favoured hypothesis) The specimen is a cluster of five individual sporophytes still attached to the remains of a small female or bisexual gametophyte. In the latter case, this fossil is evidence that reduced thalloid gametophytes and branched axial sporophytes are plesiomorphic among the earliest eutracheophytes. We suggest that a major difference in life cycle defines a basal dichotomy in tracheophytes. Eutracheophyta, including all living vascular plants, have a heteromorphic, sporophyte dominant alternation of generations, whereas their extinct sister-group Rhymopsida (renamed here Paratracheophyta) is characterised by a more or less isomorphic alternations of generations. (c) 2006 Elsevier B.V. All rights reserved. [less ▲]

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See detailBulletin de la Société Voltaire n°12
Tilkin, Françoise ULg

E-print/Working paper (2006)

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See detailQuestions de didactique du français langue seconde (cycle de conf.)
Defays, Jean-Marc ULg

Scientific conference (2006, December)

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See detailBuilding EnCOrE : Encyclopédie de Chimie Organique Electronique
Colaux, Catherine ULg; Seleck, Caroline; Henry, Julie et al

Poster (2006, December)

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See detailLe portrait dans Daguerréotypes d'Agnès Varda
Van Cauwenberge, Geneviève ULg

Conference (2006, December)

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See detailExperimental tests for the Babu-Zee two-loop model of Majorana neutrino masses
Aristizabal Sierra, Diego ULg; Hirsch, M.

in Journal of High Energy Physics [=JHEP] (2006), 0612

The smallness of the observed neutrino masses might have a radiative origin. Here we revisit a specific two-loop model of neutrino mass, independently proposed by Babu and Zee. We point out that current ... [more ▼]

The smallness of the observed neutrino masses might have a radiative origin. Here we revisit a specific two-loop model of neutrino mass, independently proposed by Babu and Zee. We point out that current constraints from neutrino data can be used to derive strict lower limits on the branching ratio of flavour changing charged lepton decays, such as μ→eγ. Non-observation of Br(μ→eγ) at the level of 10^(−13) would rule out singly charged scalar masses smaller than 590 GeV (5.04 TeV) in case of normal (inverse) neutrino mass hierarchy. Conversely, decay branching ratios of the non-standard scalars of the model can be fixed by the measured neutrino angles (and mass scale). Thus, if the scalars of the model are light enough to be produced at the LHC or ILC, measuring their decay properties would serve as a direct test of the model as the origin of neutrino masses. [less ▲]

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See detailGeneralized Shape And Topology Optimization: Recent Developments And Application Perspectives To Automotive Structures
Duysinx, Pierre ULg; Van Miegroet, Laurent ULg; Remouchamps, Alain et al

in New Advances in Body Engineering - Lightweight design, passive safety, pedestrian protection, and numerical optimization (2006, December)

More than 15 years after the seminal work by Bendsøe and Kikuchi, topology optimization of structures has taken advantage of my research efforts and has now become a commercial available tool (e.g ... [more ▼]

More than 15 years after the seminal work by Bendsøe and Kikuchi, topology optimization of structures has taken advantage of my research efforts and has now become a commercial available tool (e.g. OptiStruct by Altair, Topol by Samtech, etc.). These software tools are daily used in automotive industry and provide engineers with a rational tool for preliminary design of efficient structural components. This paper presents the status of available topology optimization tools and introduces the recent developments that extend their capabilities in order to handle stress constraints, manufacturing constraints, etc. The communication also presents a novel approach of generalized shape optimization that has been introduced to circumvent the difficulties of parametric shape optimization and to complement topology optimization. The approach is based on the eXtended Finite Element Method (XFEM) and the Level Set Description of the geometry. The Level Set description introduces smooth curve descriptions and allows modifying the connectivity of the wholes. The XFEM works with a fixed mesh as in topology optimization, which makes the method very convenient for engineers. Thus the novel approach is likely to bring the next future evolution of structural optimization. Impressive capabilities of this new generation approach will be demonstrated. Application examples from automotive and aerospace engineering will illustrate the different possibilities offered by two approaches. [less ▲]

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See detailPredictable disruption tolerant networks and delivery guarantees
François, Jean-Marc; Leduc, Guy ULg

Report (2006)

This article studies disruption tolerant networks (DTNs) where each node knows the probabilistic distribution of contacts with other nodes. It proposes a framework that allows one to formalize the ... [more ▼]

This article studies disruption tolerant networks (DTNs) where each node knows the probabilistic distribution of contacts with other nodes. It proposes a framework that allows one to formalize the behaviour of such a network. It generalizes extreme cases that have been studied before where (a) either nodes only know their contact frequency with each other or (b) they have a perfect knowledge of who meets who and when. This paper then gives an example of how this framework can be used; it shows how one can find a packet forwarding algorithm optimized to meet the 'delay/bandwidth consumption' trade-off: packets are duplicated so as to (statistically) guarantee a given delay or delivery probability, but not too much so as to reduce the bandwidth, energy, and memory consumption. [less ▲]

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See detailTreating gliomas with glucocorticoids: from bedside to bench
Piette, Caroline ULg; Munaut, Carine ULg; Foidart, Jean-Michel ULg et al

in Acta Neuropathologica (2006), 112(6), 651-664

Glucocorticoids are used in the treatment of gliomas to decrease tumour-associated oedema and to reduce the risk of acute encephalopathy associated with radiotherapy. However, the mechanisms by which ... [more ▼]

Glucocorticoids are used in the treatment of gliomas to decrease tumour-associated oedema and to reduce the risk of acute encephalopathy associated with radiotherapy. However, the mechanisms by which glucocorticoids work are still largely unknown. In this paper, we survey the experimental and clinical evidence for the effects of glucocorticoids on tumour cell proliferation, apoptosis and sensitivity to chemotherapy, angiogenesis and vascular permeability. We then review current guidelines on the choice of molecule, dose and duration of glucocorticoid treatment for gliomas. [less ▲]

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See detailSynthesis of block copolymers and their use for biomedical applications
Jérôme, Christine ULg

Conference (2006, December)

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See detailFunctional morphology of the sonic apparatus in Ophidion barbatum (Teleostei, Ophidiidae)
Parmentier, Eric ULg; Fontenelle, N.; Fine, M. L. et al

in Journal of Morphology (2006), 267(12), 1461-1468

Most soniferous fishes producing sounds with their swimbladder utilize relatively simple mechanisms: contraction and relaxation of a unique pair of sonic muscles cause rapid movements of the swimbladder ... [more ▼]

Most soniferous fishes producing sounds with their swimbladder utilize relatively simple mechanisms: contraction and relaxation of a unique pair of sonic muscles cause rapid movements of the swimbladder resulting in sound production. Here we describe the sonic mechanism for Ophidion barbatum, which includes three pairs of sonic muscles, highly transformed vertebral centra and ribs, a neural arch that pivots and a swimbladder whose anterior end is modified into a bony structure, the rocker bone. The ventral and intermediate muscles cause the rocker bone to swivel inward, compressing the swimbladder, and this action is antagonized by the dorsal muscle. Unlike other sonic systems in which the muscle contraction rate determines sound fundamental frequency, we hypothesize that slow contraction of these antagonistic muscles produces a series of cycles of swimbladder vibration. [less ▲]

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