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See detailTemporal shift of diet in alternative cannibalistic morphs of the tiger salamander
Denoël, Mathieu ULg; Whiteman, Howard H.; Wissinger, Scott A.

in Biological Journal of the Linnean Society (2006), 89(2), 373-382

Evolutionary theory predicts that alternative trophic morphologies are adaptive because they allow a broad use of resources in heterogeneous environments. The development of a cannibal morphology is ... [more ▼]

Evolutionary theory predicts that alternative trophic morphologies are adaptive because they allow a broad use of resources in heterogeneous environments. The development of a cannibal morphology is expected to result in cannibalism and high individual fitness, but conflicting results show that the situation is more complex. The goal of the present study was to increase our understanding of the ultimate benefits of a cannibalistic polyphenism by determining temporal changes in the feeding habits and biomass intake in a population of tiger salamanders (Ambystoma tigrinum nebulosum). Cannibals in this species develop a larger head than typicals and have prominent teeth, both useful for consuming large prey. Although cannibalism was only detected in cannibal morphs, large temporal variation in resource partitioning was found between morphs. The two morphs always differed in their foraging habits, but cannibalism mainly occurred immediately after the ontogenetic divergence between morphs. Cannibals shifted their foraging later to a more planktivorous diet (i.e. the primarily prey of the typical morph). Cannibals also obtained more prey biomass than typicals. These results indicate that the cannibalistic morph is advantageous over the typical development, but that these advantages vary ontogenetically. Although the results obtained are consistent with models predicting the maintenance of cannibalism polyphenism in natural populations, they show that the foraging tactics utilized by cannibal morphs, and the fitness consequences accrued by such tactics, are likely to be more complex and dynamic than previous studies have suggested. (c) 2006 The Linnean Society of London. [less ▲]

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See detailDetermination of Vs-models for the Basel region: Comparison between Array measurements, SASW and S-wave reflection
Havenith, Hans-Balder ULg; Polom, Ulrich; Fäh, Donat et al

in Geophysical Research Abstracts (2006)

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See detailParasites and the island syndrome: the colonization of the western Mediterranean islands by Heligmosomoides polygyrus (Dujardin, 1845)
Nieberding, Caroline M. ULg; Morand, S.; Libois, Roland ULg et al

in Journal of Biogeography (2006), 33(7), 1212-1222

Aim Populations of free-living vertebrates on islands frequently differ from their mainland counterparts by a series of changes in morphometric, life-history, behavioural, physiological and genetic traits ... [more ▼]

Aim Populations of free-living vertebrates on islands frequently differ from their mainland counterparts by a series of changes in morphometric, life-history, behavioural, physiological and genetic traits, collectively referred to as the 'island syndrome'. It is not known, however, whether the 'island syndrome' also affects parasitic organisms. The present study establishes the colonization pattern of the Mediterranean islands by the nematode Heligmosomoides polygyrus, a direct and specific parasite of rodent hosts of the Apodemus genus, and evaluates the effects of island colonization by this species on two components of the island syndrome: the loss of genetic diversity and the enlargement of the ecological niche. Location Heligmosomoides polygyrus was sampled on seven western Mediterranean islands - Corsica, Crete, Elba, Majorca, Minorca, Sardinia and Sicily - as well as in 20 continental locations covering the Mediterranean basin. Methods The mitochondrial cytochrome b gene (690 base pairs) was sequenced in 166 adult H. polygyrus individuals sampled in the 27 continental and island locations. Phylogenetic reconstructions in distance, parsimony, maximum likelihood and Bayesian posterior probabilities were carried out on the whole cytochrome b gene data set. The levels of nucleotide, haplotype and genetic divergence (Kimura two-parameter distance estimator) diversities were estimated in each island population and in the various continental lineages. Results Phylogenetic reconstructions show that the mainland origins of H. polygyrus were continental Spain for the Balearic Islands (Majorca, Minorca), northern Italy for the Tyrrhenian Islands (Corsica, Sardinia, Elba), southern Italy for Sicily, and the Balkan region for Crete. A comparison of island H. polygyrus populations with their mainland source populations revealed two characteristic components of the island syndrome in this parasite. First, island H. polygyrus populations display a significant loss of genetic diversity, which is related (r(2) = 0.73) to the distance separating the island from the mainland source region. Second, H. polygyrus exhibits a niche enlargement following insularization. Indeed, H. polygyrus in Corsica is present in both A. sylvaticus and Mus musculus domesticus, while mainland H. polygyrus populations are present exclusively in Apodemus hosts. Main conclusions Our results show that H. polygyrus has undergone a loss of genetic diversity and a niche (host) enlargement following colonization of the western Mediterranean islands. To our knowledge, this study provides the first evidence for components of the 'island syndrome' in a parasitic nematode species. [less ▲]

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See detailInter- and intra-guild interactions related to aphids in nettle (Urtica dioica L.) strips closed to field crops.
Alhmedi, A.; Haubruge, Eric ULg; Bodson, Bernard ULg et al

in Communications in Agricultural and Applied Biological Sciences (2006), 71(2 Pt B), 413-23

A field experiment designed to assess the biodiversity related to nettle strips closed to crops, and more particularly the aphid and related beneficial populations, was established in experimental farm ... [more ▼]

A field experiment designed to assess the biodiversity related to nettle strips closed to crops, and more particularly the aphid and related beneficial populations, was established in experimental farm located in Gembloux (Belgium). Margin strips of nettle (Urtica dioica) closed to wheat (Triticum aestivum), green pea (Pisum sativum) and rape (Brassicae napus) fields were investigated. The diversity, abundance of aphids and related predators were analysed according to the plant crop species and the differential pesticide application (treated plot and control). Insects were visually observed every week during all the cultivation season. Two main families of aphidophagous predators were found in all field crops and nettle, the Coccinellidae and Syrphidae. The diversity of the aphidophagous predators was shown to be higher on nettle than in field crops, particularly the Chrysopidae, the Anthocoridae and the Miridae. However, a striking difference of ladybird abundance was observed according to the aphid host plant. In one side, Coccinella septempunctata was much more abundant on Acyrthosiphon pisum infested green pea than on the other host plant species. At the opposite, higher occurrence of Harmonia axyridis was observed on the aphid infested nettle plants than on the crop plants. In particular, none of H. axyridis was found in wheat crop. Also, more than only a significant positive correlation between predator and aphid abundance, specialised relations between particular aphid species and some so-called generalist predators was determined in the fields. Finally, intraguild interactions between the aphidophagous predators was assessed and shown that only a significant negative correlation between Episyrphus balteatus and H. axyridis related to the nettle aphid, Micrlophium carnosum, was observed. The relative distribution of the ladybirds, namely C. septempunctata and H. axyridis according to the host plant, nettle strips and crop plots was discussed in relation to integrated pest management approach. [less ▲]

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See detailComparison of noise, hot and cold contrast of eight tomographic camera models.
Seret, Alain ULg; Nguyen, Thibaut

in European Journal of Nuclear Medicine and Molecular Imaging (2006), 33(S2), 282

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See detailSérologie infectieuse: interprétation des résultats et pièges à éviter
Huynen, Pascale ULg; Hayette, Marie-Pierre ULg; Melin, Pierrette ULg et al

in Revue Médicale de Liège (2006), 61(12), 827-833

In Medical Microbiology, in addition to the direct methods of indentification of infectious agentss, the serologic indirect techniques by quantification of antibodies have extremely useful in infectiology ... [more ▼]

In Medical Microbiology, in addition to the direct methods of indentification of infectious agentss, the serologic indirect techniques by quantification of antibodies have extremely useful in infectiology, for the diagnosis and the therapeutic or vaccination follow-up as well as for epidemiologic enquiries, serodiagnosis methods have significantly improved. Meanwhile, results may reveal hard to interpret, especially when are tries to specify the time of the beginning of an infection. The results require in the majority of the cases to be compared on two subsequent serum samples, to observe a possible increase in antibodies level. In addition, the infectious serology results may not be considered as the only element of final diagnosis. In all cases, they have to be interpreted and challenged against the clinical context. [less ▲]

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See detailEléments de paléontologie
Javaux, Emmanuelle ULg

Learning material (2006)

powerpoint sur MyULg

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See detailBibliographie sélective
Provenzano, François ULg

in Denis, Benoît; De Marneffe, Daphné (Eds.) Les réseaux littéraires (2006)

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See detailMAXIMIZATION OF PULL-IN VOLTAGE OF MICRO-ELECTROMECHANICAL STRUCTURES USING TOPOLOGY OPTIMIZATION
Lemaire, Etienne ULg; Rochus, Véronique ULg; Fleury, Claude ULg et al

Conference (2006)

The design problem consists in maximizing the pull-in voltage using topology optimization method, which is formulated as an optimal material distribution. In addition to the classical volume constraint ... [more ▼]

The design problem consists in maximizing the pull-in voltage using topology optimization method, which is formulated as an optimal material distribution. In addition to the classical volume constraint, different structural constraints could be taken into consideration. Sensitivity analysis is one of the key issues of the optimization process and is performed with the formulation of eigenvalue topology optimization problems. Here the paper investigates topology optimization of strongly coupled electromechanical systems. To avoid important modifications of the electric field by the optimization process, this first study considers a non design electrode and use topology optimization to design an optimal suspension structure. Solution procedure of the optimization problem is based on CONLIN optimizer using a sequential convex programming. This method that has proved its efficiency in many structural problems (sizing, shape) is here tailored to strongly coupled multiphysics design problems under consideration. The choice of appropriate explicit convex approximations schemes for multiphysic problems is investigated. The proposed method is illustrated and validated on microbeam optimization applications. [less ▲]

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See detailDiagnosis of osteoporosis without prevalent fractures: are we missing our main target?
Richy, F.; Reginster, Jean-Yves ULg

in Osteoporosis Action (2006), 1

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See detailVertebrate origins: does the tunic make the man?
Delsuc, Frédéric; Baurain, Denis ULg; Philippe, Hervé

in Medecine Sciences : M/S (2006), 22(8-9, AUG-SEP), 688-690

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See detailStress constrained optimization using X-FEM and Level-Set description
Van Miegroet, Laurent ULg; Jacobs, Thibault; Lemaire, Etienne ULg et al

in Proceedings of III European Conference on Computational Mechanics. Solids, Structures and Coupled Problems in Engineering (2006)

This paper presents and describes an intermediate approach which takes its place between the two classical methods of shape and topology optimization. It is based on using the recent Level Set description ... [more ▼]

This paper presents and describes an intermediate approach which takes its place between the two classical methods of shape and topology optimization. It is based on using the recent Level Set description of the geometry and the novel eXtended Finite Element Method (X-FEM). The method benefits from the fixed mesh work using X-FEM and from the curves smoothness of the Level Set description. Design variables are shape parameters of basic geometric features. The number of design variables of this formulation remains small whereas various global and local constraints can be considered. A key problem which is investigated here is the sensitivity analysis and the way it can be carried out precisely and efficiently. Numerical applications revisit some classical 2D (academic) benchmarks from shape optimization and illustrate the great interest of using X-FEM and Level Set description together. The paper presents the results of stress constrained problems using the proposed X-FEM and Level Set based formulation. A central issue is the sensitivity analysis (related to the compliance and/or the stresses) and the way it can be carried out efficiently. A special attention is also paid to stress constrained problems which are often neglected in other Level Set Methods works. [less ▲]

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See detailA scale transition procedure for flexural effects
Mercatoris, Benoît ULg; Massart, Thierry J.

in 7th National Congress on Theoretical and Applied Mechanics (NCTAM2006) (2006)

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See detailFeasability of forest conversion: ecological, social and economic aspects (FEFOCON)
Verheyen, Kris; Lust, Noel; Carnol, Monique ULg et al

Report (2006)

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See detailBaryon resonances in large N(c) QCD
Matagne, Nicolas; Stancu, Floarea ULg

in Bled Workshops in Physics (2006), 7(1), 61-66

The baryon spectra are discussed in the context of the $1/N_c$ expansion approach, with emphasis on mixed symmetric states. The contributions of the spin dependent terms as a function of the excitation ... [more ▼]

The baryon spectra are discussed in the context of the $1/N_c$ expansion approach, with emphasis on mixed symmetric states. The contributions of the spin dependent terms as a function of the excitation energy are shown explicitly. At large energies these contributions are expected to vanish. [less ▲]

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See detailTreatment of anaemia with erythropoietin
Beguin, Yves ULg; Dujardin, C.; Piron, Maude ULg et al

in Brugnara, C.; Beaumont, C. (Eds.) ESH Scientific Updates. Disorders of Iron Homeostasis, Erythrocytes and erythropoiesis (2006)

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See detailQuantitative approach to the conservation of a tropical seabird population in the western Indian Ocean
Monticelli, David; Ramos, J. A.; Doucet, Jean-Louis ULg et al

Poster (2006)

The roseate tern (Sterna dougalli) is an oceanic seabird species showing mainly a tropical distribution, with a relatively fragile status worldwide. It was still recently considered as a "near-threatened ... [more ▼]

The roseate tern (Sterna dougalli) is an oceanic seabird species showing mainly a tropical distribution, with a relatively fragile status worldwide. It was still recently considered as a "near-threatened" (IUCN red list) due to the strong decline in population trends over the last decades. For instance, the annual breeding population found on Aride Island, western Indian Ocean, has fluctuated between a high of 4,000 in the 1970's to a low of 60-1200 pairs from 2000 onwards. As a result, an intensive monitoring program was conducted on Aride between 1998 and 2006 in order to understand how environmental factors may affects this breeding population. This included the estimation of annual productivity (no of chicks fledged per pair), demographic parameters such as survival rate and recruitment (age-specific breeding probabilities), and their affecting co-factors (e.g. food availability, tick parasitism,...). We suggest that these three parameters (productivity, survival, recruitment) constitute the necessary basis to model the life-cycle of this population, and, ultimately, to provide local managers with conservations measures. [less ▲]

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See detailDutch Literature [YWMLS]
Steyaert, Kris ULg

in Parkinson, Steven; Barber, Lisa (Eds.) The Year's Work in Modern Language Studies (2006)

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See detailAnalytical validation of potentiometric method for cetirizinium ion
Rachidi, Mohamed ULg; Digua, K.; Hubert, Philippe ULg et al

in Analytical Letters (2006), 39(8), 1699-1708

Accuracy and reliability of the analytical results are crucial for ensuring quality, safety, and efficacy of pharmaceutical products. However, to ensure these criteria, analytical validation is required ... [more ▼]

Accuracy and reliability of the analytical results are crucial for ensuring quality, safety, and efficacy of pharmaceutical products. However, to ensure these criteria, analytical validation is required. In this matter, many official documents describing the criteria of validation are available. However, these concern mainly chromatography analysis and bio-analytical methods of pharmaceutical products, but they do not propose any experimental protocol for direct potentiometric methods using ion-selective electrodes applied in pharmaceutical analysis. In this work, we are proposing a validation strategy based on the normative and regulatory guidelines applied to a potentiometric method with a polymeric membrane selective to cetirizine dihydrochloride. The statistical analysis obtained from raw data is described for all steps of this protocol. Also this validated method was successfully applied to the determination of cetirizine in pharmaceutical preparations using direct potentiometry with a mean relative standard deviation of 0.57% and a mean recovery of 99.63%. [less ▲]

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