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See detailComparaison empirique des méthodes classiques de détection du fonctionnement différentiel d’items en psychométrie
Magis, David ULg; De Boeck, Paul; Raîche, Gilles

in Raîche, Gilles; Paquette-Côté, Karine; Magis, David (Eds.) Des mécanismes pour assurer la validité de l’interprétation de la mesure en éducation. Tome 1 : la mesure. (2011)

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See detailComparaison empirique des méthodes classiques de détection du fonctionnement différentiel d’items en psychométrie
Magis, David ULg; De Boeck, Paul; Raîche, Gilles

Conference (2009, May)

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See detailComparaison entre deux techniques d'étude de l'utilisation de l'habitat par la sérotine commune (Eptesicus serotinus): le radiopistage et la prospection avec une détecteur d'ultrasons hétérodyne.
Motte, Gregory; Kervyn, Thierry; Libois, Roland ULg

in Arvicola (1998), Arvicola

During the course of a study on the use of habitat by the common serotine bat in Belgium, we have had recourse to radiotracking and the prospecting with an ultrasonic detector. The results obtained with ... [more ▼]

During the course of a study on the use of habitat by the common serotine bat in Belgium, we have had recourse to radiotracking and the prospecting with an ultrasonic detector. The results obtained with the two techniques used have been compared. The preferred habitats of the bats were found identical with the two techniques, with a preferece for leafy environments. However, the interpretation of the results affords different information depending on the technique adopted. We have thus compared the limits of each of the two techniques. In conclusion, the results obtained by radiotracking and with the ultrasonic detector are at the same time virtually the same but also complementary. [less ▲]

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See detailComparaison entre l'huile de colza pure et le gasoil EN590
Lumaye, François ULg

Scientific conference (2012, February 29)

The experimental farm of GxABT-Université de Liège has a Deutz-Fahr M650 "Natural Power" tractor which is factory designed for rape oil. Indeed it's equipped with two fuel tanks: one for the EN590 gasoil ... [more ▼]

The experimental farm of GxABT-Université de Liège has a Deutz-Fahr M650 "Natural Power" tractor which is factory designed for rape oil. Indeed it's equipped with two fuel tanks: one for the EN590 gasoil and another for rape oil. A fuel consumption test show that rape oil running increase fuel consupmtion for more or less one liter per hour. [less ▲]

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See detailComparaison entre le profil vertical de la vitesse du vent observé dans les basses couches de la troposphère et celui simulé par le modèle WRF en Belgique
Doutreloup, Sébastien ULg; Fettweis, Xavier ULg; Beaumet, Julien ULg et al

in Camberlin, Pierre; Richard, Yves (Eds.) Actes du XXVIIe Colloque de l'Association Internationale de Climatologie : CLIMAT : SYSTÈME & INTERACTIONS (2014, July 02)

In the framework of FLEXIPAC project funded by the "RELIABLE" program of Walloon Region (Belgium), the Laboratory of Climatology Topoclimatology (LCT) of the University of Liège (Belgium) aims to adjust ... [more ▼]

In the framework of FLEXIPAC project funded by the "RELIABLE" program of Walloon Region (Belgium), the Laboratory of Climatology Topoclimatology (LCT) of the University of Liège (Belgium) aims to adjust the WRF regional model (v.3.4.) forced by the ERA-Interim reanalysis for Belgium. Our analysis shows that wind speeds at 100m simulated by WRF are systematically overestimated compared to wind speeds extracted from wind productions of two wind farms. In order to solve this problem, four ways are considered in this contribution. The first way is to compare the WRF model with the reanalysis data. The second way is to test the influence of the spatial resolution by running WRF with a finer resolution. The third way is to smooth WRF outputs, where in order to analyze the variability created by the model. And finally, the fourth way is to compare the WRF model with the MAR (v3.3.) regional model. This last way seems to confirm that the MAR model better simulates wind speeds at 10m and at 100m than the WRF model. [less ▲]

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See detailComparaison histologique et comportementale de différentes souches de souris après un épisode d’ischémie cérébrale
Fassotte, Ludivine ULg

Master's dissertation (2011)

L’ischémie cérébrale, qui correspond à une interruption du flux sanguin causée par l’obstruction d’une artère cérébrale, est occasionnée dans plus de 80% des AVCs humains. Cette maladie neurologique est ... [more ▼]

L’ischémie cérébrale, qui correspond à une interruption du flux sanguin causée par l’obstruction d’une artère cérébrale, est occasionnée dans plus de 80% des AVCs humains. Cette maladie neurologique est la seconde cause de mortalité dans les sociétés industrialisées et son impact est lourd sur les survivants. En effet, elle génère des déficits fonctionnels subsistant pendant des mois, voire des années. Ce travail s’inscrit dans la perspective de développement d’un traitement permettant une récupération fonctionnelle de ces déficits par la recherche de techniques permettant de mimer un AVC humain sur différentes souches de rongeurs. Le présent travail consiste en la mise en place d’une batterie de tests comportementaux permettant l’évaluation à court et à long terme des déficits sensorimoteurs, comportementaux et cognitifs causés par une ischémie cérébrale expérimentale de 30 minutes induite par la technique d’occlusion de l’artère cérébrale moyenne (MCAo) à droite. Dans cette perspective, deux souches murines couramment utilisées en laboratoire, 129S2/SvPas et C57Black6J ont été comparées. Une semaine puis trois semaines après l’opération, les capacités sensorimotrices des animaux sont évaluées à l’aide du rotarod, du pole test, du test d’agrippement tandis que l’activité locomotrice et l’anxiété sont mesurées dans un open field. Après un mois, l’endurance et la motivation sont testées par un programme de FR progressif alors que la flexibilité cognitive est évaluée à l’aide du programme du reversal learning. Au terme de l’évaluation comportementale, le cerveau des animaux est prélevé et l’étendue de la lésion cérébrale est évaluée à l’aide d’une révélation immunohistochimique utilisant le marquage anti-neuronal NeuN. Les résultats témoignent d’un effet significatif de l’ischémie chez la souche C57 sur les capacités sensorimotrices des animaux (rotarod et locomotion). Les résultats au FR progressif montrent qu’une ischémie de 30 minutes altère l’endurance des animaux lorsque le nombre d’appuis demandé est élevé. De même, un trouble des fonctions exécutives est également observé (passage d’un comportement à un autre). La lésion occasionnée par l’ischémie touche le striatum dorsolatéral chez les deux souches ainsi qu’une portion plus moins étendue du cortex cérébral dans le cas de la souche C57. L’étendue plus ou moins importante de la lésion est liée à l’anatomie vasculaire cérébrale qui est variable d’une souche à l’autre. Puisque le cortex moteur n’est pas affecté, les troubles observés sont probablement liés à la lésion du striatum, une portion du cerveau qui est étroitement connectée avec le cortex moteur. A l’issue de ces expériences, l’utilisation de la souche C57 semble être plus appropriée à l’étude de l’ischémie cérébrale transitoire chez la souris que la souche 129S2. Le présent travail montre que l’établissement d’une batterie de tests comportementaux sensibles à l’ischémie doit comporter à la fois des tests sensorimoteurs afin de déceler des troubles transitoires tels que la coordination motrice et l’endurance. Une telle batterie doit également comporter des tests cognitifs détectant des déficits subsistant à long terme tels que les troubles de la fonction exécutive. La sélection d’un modèle animal le plus approprié ainsi que la mise en place d’une telle batterie de tests permettront idéalement de corréler les déficits observés et les structures nerveuses impliquées dans les fonctions touchées par l’ischémie cérébrale. Dès que ces bases auront été posées, de nouveaux traitements appropriés pourront alors être testés. [less ▲]

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See detailUne comparaison internationale des systèmes de santé. A la recherche de l’efficacité et de l’équité
Fecher-Bourgeois, Fabienne ULg

Conference given outside the academic context (2013)

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See detailComparaison of dust concentrations in pig buildings and in an environmental inhalation chamber
Urbain, B.; Gustin, P.; Nicks, Baudouin ULg

in Proceedings of the 12th Congress of the International Pig Veterinary Society (1992)

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See detailComparaison of the allergenicity of the zymogen and mature form of Der p 3.
Bouaziz, Ahlem ULg

Poster (2013, February)

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See detailComparaison of the flower scents of two Impatiens species
Marlet, Christelle ULg; Lognay, Georges ULg; Jacquemart, Anne-Laure et al

Poster (2010, September 27)

The Giant balsam, Impatiens glandulifera Royle (Balsaminaceae) was introduced in Europe from the Himalayas as a garden ornamental plant in 1839. Due to its great success from nursery gardeners (1), it is ... [more ▼]

The Giant balsam, Impatiens glandulifera Royle (Balsaminaceae) was introduced in Europe from the Himalayas as a garden ornamental plant in 1839. Due to its great success from nursery gardeners (1), it is now considered as one of the 100 worst invasive species in Europe. On the contrary, the native I. noli-tangere L. is considered to be in decline. Both species are annuals that absolutely need reproductive output to maintain or extend their populations. High fecundity has frequently been associated with invasiveness. However, traits controlling the reproductive success like pollinator attractiveness have not yet been assessed. The alien species is profusely visited by bumblebees which constituted the main visitors and efficient pollinators (2-3). The native also presents traits linked to insect attractiveness. Flowers produced similar quantities of nectar with the same sugar concentration and composition than the exotic. Therefore, the native could be considered as valuable source of nectar for pollinators. Despite the fact that nectar reward is likely to influence pollinator attractiveness, I. noli-tangere only occasionally received visits. Indeed, a flower of the native is 40 times less visited than a I. glandulifera flower (3). Differences in visitation rates may be explained by several factors, as floral scents, UV patterns or floral display. In summer 2009, a first comparative study of floral scents between these two species was performed. An active sampling in a small glass chamber able to contain single flower left on the plant had been performed on a sorbent tube with Carbograph and Tenax TA. The volatiles of floral scents had been analysed by thermal desorption coupled to gas chromatography and mass spectrometry (4, 5). The composition of flower scents on the basis of area percent of identified peaks had been compared. Terpenes (d-limonene, α-terpinolene, p-cymene, α and β-terpineol) were emitted by the flowers of both species. Higher monoterpenes proportion in area percent was detected for the native species. Terpenes such as β-myrcene, 1,4-cineole, eucalyptol, carveol were absent in the flower scent of the alien I. glandulifera. However, the alien presented a higher alcane proportion. The implication of terpenes in the attractiveness of bumblebees will be studied. [less ▲]

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See detailComparaison of three supplements high in linseeds or linseed oil in dairy cows
Cabaraux, Jean-François ULg; Marche, C.; Hornick, Jean-Luc ULg et al

in Book of absracts of the 54th Annual Meeting of the European Association for Animal Production (2003)

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See detailComparaison par modélisation de la production de ruissellement de toitures stockantes (toitures végétalisées et toiture bac)
Beckers, Eléonore ULg

Master's dissertation (2007)

Rainwater runoff management is becoming extremely complex as the result of the increasingly impervious nature of urban and suburban surfaces. Urbanisation can indeed lead to high volumes of surface water ... [more ▼]

Rainwater runoff management is becoming extremely complex as the result of the increasingly impervious nature of urban and suburban surfaces. Urbanisation can indeed lead to high volumes of surface water runoff. This undesirable effect could be reduced by disconnecting roofs from the sewer system. This study represents a first attempt to establish a model concerning green roofs and flat roof storage systems based on a physical approach method. The aim is to deduce their respective effect on water runoff management by analysing and comparing their performance based on a long period of meteorological conditions data (1989-1995). [less ▲]

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See detailComparaison par simulation de 3 types d'unités d'échantillonage en futaies feuillues de hêtre (Fagus silvatica L.).
Hebert, Jacques ULg; Rondeux, Jacques ULg; Laurent, C.

in Annales des Sciences Forestières (1988), 45(3), 209-222

This study is dealing with the choice of the size and the type of sampling units which could be used in inventories of beech stands (Fagus silvatica L.). Two experimental areas of 16 hectares have been ... [more ▼]

This study is dealing with the choice of the size and the type of sampling units which could be used in inventories of beech stands (Fagus silvatica L.). Two experimental areas of 16 hectares have been considered in evenaged and unevenaged structures. Three types of sampling units were studied : fixed circular plots, Bitterlich plots (non fixed circular plots) and circular plots including a minimum of number of trees (15-20). As regards to the estimations of basal area and number of trees per hectare there is no significative difference between plots of fixed area and plots including a minimum number of trees even if plot sizes and stand structure vary. As expected, compared to the other methods, the Bitterlich plots give little more precise estimations of basal area and less precise estimations of number of trees. The plots with a minimum number of trees would give higher values compared to the other types of plots but no significative difference have been observed. Numerous simulations show that in case of a fixed total cost the use of a great number of small units or of a limited number of large units has little effect on the standard error of estimations. The concept of minimum number of trees (15-20) seems to be valuable according to a compromise between precision and cost. To avoid a risk of bias in stands including large empty zones, it is preferable to use plot radii suitable to normal conditions. [less ▲]

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See detailComparaison pratique de quelques méthodes d'analyse discriminante
Lazaar, N.; Palm, Rodolphe ULg

in Biométrie-Praximétrie (1994), 34

Dans cette étude, on compare les performances des trois méthodes d'analyse discriminante suivantes : analyse discriminante linéaire, analyse discriminante quadratique et analyse discriminante logistique ... [more ▼]

Dans cette étude, on compare les performances des trois méthodes d'analyse discriminante suivantes : analyse discriminante linéaire, analyse discriminante quadratique et analyse discriminante logistique. Les performances sont étudiées dans le cas de données réelles, en envisageant diverses transformations de variables destinées à modifier les conditions de normalité et d'égalité des variances entre populations. Aucune différence significative de performances entre méthodes n'a pu être mise en évidence au niveau de signification de 0,05. Par contre, les performances des trois méthodes diminuent quand les distributions des variables sont nettement non normales ou de variances très inégales. Différentes estimations des taux d'erreur ont également été comparées : resubstitutin, extraction-insertion et utilisation d'un échantillon-test. Les résultats ont montré que, par rapport à l'utilisation d'échantillons-tests, la méthode de resubstitution sous-estime le taux d'erreur. Cette sous-estimation est de l'ordre de 13 % du taux d'erreur réel. La méthode d'extraction-insertion donne par contre des résultats très semblables à la méthode utilisant un échantillon-test. [less ▲]

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See detailComparaison quantitative de différentes techniques de restauration rapide dans les réseaux IP/MPLS
Mélon, Laurent; Leduc, Guy ULg

in Obaid, A. (Ed.) Ingénierie des protocoles - Réseaux mobiles et ad hoc, qualité de service, multimédia, ingénierie de trafic (2002, May 27)

This article is dealing with a quantitative comparison of different fast restoration approaches in the context of a Multi-Protocol Label Switching (MPLS) network. The objective is to analyse the general ... [more ▼]

This article is dealing with a quantitative comparison of different fast restoration approaches in the context of a Multi-Protocol Label Switching (MPLS) network. The objective is to analyse the general behaviour of these approaches (local rerouting, edge-to-edge rerouting, ...) in case of failure by means of simulations. This study is realised in the context of Best Effort only traffic, routing being done with a shortest paths algorithm. Many papers justify the choice between an edge-to-edge or a local scheme by means of intuition and then present a new algorithm for routing backup paths which try to optimize some parameters. Our approach aims to clarify the situation by comparing by means of concrete results the pros and cons of each mechanism. [less ▲]

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See detailComparaisons calculs-essais pour l'éprouvette cylindrique
Beckers, Pierre ULg; Debongnie, Jean-François ULg; Masset, Luc ULg

Report (1996)

In this first application of the machining simulation tool prototype, great difficulties were encountered in the interpretaion of the physical test. In fact, parasitic deformations occured, with a three ... [more ▼]

In this first application of the machining simulation tool prototype, great difficulties were encountered in the interpretaion of the physical test. In fact, parasitic deformations occured, with a three-lobed form. This implied the necessity of filtering the experimental data and a physical interpretation of the undue deformation. A theoretical study is performed, leading to the result that this phenomenon is due to the combined effect of the clearance of the clamping jaws and the pre-stress of the dead center. [less ▲]

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See detailComparaisons calculs-essais pour le carter d'alimentation d'huile TA96
Beckers, Pierre ULg; Debongnie, Jean-François ULg; Masset, Luc ULg

Report (1996)

On this application, the computed results were in the opposite direction as compared to the physical tests. A sound analysis led to the result that a parasitic deformation was due to clamping deformations ... [more ▼]

On this application, the computed results were in the opposite direction as compared to the physical tests. A sound analysis led to the result that a parasitic deformation was due to clamping deformations. In fact, the three supports of the work were found to be unsufficiently coplanar. [less ▲]

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