Last 7 days     Results 121-140 of 16081.   2 3 4 5 6 7 8 9 10 11 12   Boucle et répétition : musique, littérature, arts visuelsBelloi, Livio ; Delville, Michel ; Levaux, Christophe et alBook published by Presses Universitaires de Liège (in press)Detailed reference viewed: 18 (2 ULg) PROPRIETES PHYSICO-CHIMIQUES ET FONCTIONNALITES TECHNOLOGIQUES DES MATIERES GRASSES VEGETALES Quelques applications alimentairesDanthine, Sabine in Christophe, Lavelle (Ed.) Science culinaire (in press)Detailed reference viewed: 10 (0 ULg) Climatological study of ionospheric irregularities over the European mid-latitude sector with GPSWautelet, Gilles ; Warnant, René in Journal of Geodesy (in press)High-frequency variability of the ionosphere, or irregularities, constitutes the main threat for real-time precise positioning techniques based on Global Navigation Satellite Systems (GNSS) measurements ... [more ▼]High-frequency variability of the ionosphere, or irregularities, constitutes the main threat for real-time precise positioning techniques based on Global Navigation Satellite Systems (GNSS) measurements. Indeed, during periods of enhanced ionospheric variability, GNSS users in the field – who cannot verify the integrity of their measurements – will experience positioning errors that can reach several decimeters, while the nominal accuracy of the technique is cm-level. In the frame of this paper, a climatological analysis of irregularities over the European mid-latitude region is presented. Based on a ten year GPS dataset over Belgium, the work analyzes the occurrence rate (as a function of the solar cycle, season and local time) as well as the amplitude of ionospheric irregularities observed at a single GPS station. The study covers irregularities either due to space weather events (solar origin) or of terrestrial origin. If space weather irregularities are responsible for the largest effects in terms of ionospheric error, their occurrence rate highly depends on solar activity. Indeed, the occurrence rate of ionospheric irregularities is about 9% during solar maximum, whereas it drops to about 0% during medium or low solar activity periods. Medium-Scale Ionospheric Disturbances (MSTIDs) occurring during daytime in autumn/winter are the most recurrent pattern of the time series, with yearly proportions slightly varying with the solar cycle and an amplitude of about 10% of the TEC background. Another recurrent irregularity type, though less frequent than MSTIDs, is the noise-like variability in TEC observed during summer nighttime, under quiet geomagnetic conditions. These summer nighttime irregularities exhibit amplitudes ranging between 8 and 15% of the TEC background. [less ▲]Detailed reference viewed: 10 (3 ULg) Interactions of lipases with milk fat globule membrane monolayers using a Langmuir film balanceDanthine, Sabine ; Blecker, Christophe in International Dairy Journal (in press)Detailed reference viewed: 14 (1 ULg) An astronomical survey conducted in BelgiumNazé, Yaël ; Fontaine, Sébastien in Physics Education (in press)This article presents the results of the first survey conducted in Belgium about the interest and knowledge in astronomy. Two samples were studied, the public at large (667 questionnaires) and students ... [more ▼]This article presents the results of the first survey conducted in Belgium about the interest and knowledge in astronomy. Two samples were studied, the public at large (667 questionnaires) and students (2589 questionnaires), but the results are generally similar in both samples. We evaluated people’s interest, main information source, and attitudes towards astronomy, as well as their supposed and actual knowledge of the subject. The main conclusion is that, despite a poor self-confidence, people do know the basic astronomical concepts. However, that knowledge is not deeply rooted, as reasoning questions show well-spread misconceptions and/or misunderstandings. [less ▲]Detailed reference viewed: 14 (5 ULg) ORIGINALApport de la musculation en sport collectifamateur : exemple du handball fémininJidovtseff, Boris ; Frère, Pauline; Theunissen, Catherine in Science & Sports (in press)SeasonalSummaryIntroduction. — The aim of the study was to verify, in a non-professional handball female, if theintroduction of two short workouts per week during all season has a positive impact on ... [more ▼]SeasonalSummaryIntroduction. — The aim of the study was to verify, in a non-professional handball female, if theintroduction of two short workouts per week during all season has a positive impact on muscularperformance.Methods. — Eighteen female playing handball at the top Belgian level were monitored duringthe complete season. Ten of these girls (‘‘Muscu’’ group) achieved, in addition to their usualtraining, two short (30 minutes) strength training sessions weekly. The other (‘‘Control’’ group)followed the usual training, without any strength training session. A battery of tests (leg power,arm power, vertical jump, sprint, throwing, flexibility) has been set up to four times during theseason to follow up muscular performance.Results. — According to the literature, the ‘‘Control’’ group showed any change in performanceduring the year. By contrast, ‘‘Muscu group results demonstrated that the short strength trai-ning program was efficient, with significant improvements in leg power (P < 0.005) and sprint(P < 0.05) tests. Increase in vertical jump was very close to the level of significance (P = 0.06).Arms power did not improve but appeared to be superior in the ‘‘Muscu’’ group in comparisonwith ‘‘Control’’ at the end of the season, which was not the case at the beginning.© 2013 Elsevier Masson SAS. All rights reserved. [less ▲]Detailed reference viewed: 57 (5 ULg) Estimating the parameters of a 3-D root distribution function from root observations with the trench profile method: case study with simulated and field-observed root dataVansteenkiste, Joachim; Van Loon, Jelle; Garré, Sarah et alin Plant and Soil (in press)Background and Aims Root length density (RLD) is a parameter that is difficult to measure, but crucial to estimate water and nutrient uptake by plants. In this study a novel approach is presented to ... [more ▼]Background and Aims Root length density (RLD) is a parameter that is difficult to measure, but crucial to estimate water and nutrient uptake by plants. In this study a novel approach is presented to characterize the 3-D root length distribution by supplementing data of the 3-D distribution of root intersections with data of root length density from a limited number of soil cores. Methods The method was evaluated in a virtual experiment using the RootTyp model and a field experiment with cauliflower (Brassica oleracea L. botrytis) and leek (Allium porrum, L.). Results The virtual experiment shows that total root length and root length distribution can be accurately estimated using the novel approach. Implementation of the method in a field experiment was successful for characterizing the growth of the root distribution with time both for cauliflower and leek. In contrast with the virtual experiment, total root length could not be estimated based upon root intersection measurements in the field. Conclusions The novel method of combining root intersection data with root length density data from core samples is a powerful tool to supply root water uptake models with root system information. [less ▲]Detailed reference viewed: 17 (5 ULg) Étude anatomoradiologique d’un crâne déformé d’Ancón (Pérou)Ricciardetto, Antonio ; Boman, Françoise; Duchat, Florent et alin Charlier, Philippe (Ed.) Actes du Ve Colloque international de Pathographie (in press)Matériels et méthodes : l’étude porte sur un crâne déformé provenant d’Ancón au Pérou, inventorié au Muséum National d’Histoire Naturelle (MNHN) de Paris en 1889. L’étude est géographique, historique ... [more ▼]Matériels et méthodes : l’étude porte sur un crâne déformé provenant d’Ancón au Pérou, inventorié au Muséum National d’Histoire Naturelle (MNHN) de Paris en 1889. L’étude est géographique, historique, macroscopique et tomodensitométrique. Résultats : situé sur la côte à 40 km au nord de Lima, la capitale du Pérou, le site d’Ancón est un site archéologique de la période lithique, et un lieu de sépulture depuis l’époque Chavín (1250 à 250 av. J.-Chr.). Dès l’époque Chavín, les peuples du Pérou ancien construisaient des centres cérémoniels dirigés par une élite théocratique, et déformaient le crâne des enfants dès les premiers jours de la vie, à l’aide de moyens de pression variés. La déformation du crâne d’Ancón est une déformation antéro-postérieure oblique, brachycéphale, bilobée et asymétrique, sans trépanation ni déformation dentaire associée. C’est une variante bilobée du type Huaura de déformation crânienne, qui est associé aux régions de Chancay-Ancón et Lima. L’étude tomodensitométrique des variations d’épaisseur de la voûte, avec amincissement en regard des zones de pression, a montré que la déformation était intentionnelle, et caractérisée par une pression fronto-pariéto-temporale bilatérale surtout antérieure et dégressive d’avant en arrière, associée à une pression frontale, occipitale, et sagittale médiane. En l’absence de contexte et de datation, l’ancienneté du crâne étudié ne peut pas être précisée au long d’une période de presque trois millénaires, jusqu’à la domination Inca et l’arrivée des Espagnols (1532). Le crâne pourrait appartenir à l’une ou l’autre des cultures successives du site d’Ancón : Chavín, Baňos de Boza o Miramar, Lima, Wari, et Chancay (1200 à 1470), dont les céramiques représentent la déformation bilobée. Le crâne est probablement celui d’une femme âgée de plus de 45 ans à son décès, de statut social élevé, faisant partie de l’élite magico-religieuse, politique et économique dirigeante. L’étude de l’endocrâne a permis d’observer la déformation des veines superficielles et des lobes du cerveau. Il existe des signes de parodonpathie chronique à un stade avancé. Un abcès d’origine dentaire pourrait avoir été la cause du décès. Conclusions et perspectives : en ce qui concerne la pratique des déformations crâniennes, la région d’Ancón-Chancay et de Lima paraît être remarquable à trois égards : par le grand nombre de crânes déformés, par le grand nombre de crânes bilobés, et par la proportion importante de femmes, dont on peut supposer qu’elles étaient nées de familles nobles, et destinées dès l’enfance à faire partie de l’élite théocratique. La reconstitution 3D de l’épaisseur de la voûte crânienne a permis pour la première fois à notre connaissance de caractériser ce type de déformation, et pourrait permettre de reconstituer l’appareil déformateur. Seule la reprise des exhumations programmées sur le site d’Ancón, dans le cadre d’un projet prospectif pluridisciplinaire, pourrait permettre de mieux préciser la proportion d’individus à crâne déformé, la proportion des crânes bilobés, et le sex ratio, dans chaque contexte historique et socio-culturel de ce type de déformation crânienne intentionnelle ; et, peut-être, de retrouver in situ l’appareil déformateur correspondant. [less ▲]Detailed reference viewed: 5 (0 ULg) ÉVOLUTION DE LA TENEUR EN EAU LE LONG D’UNE TOPOSEQUENCE FORESTIERE ARGILO-LIMONEUSEDeraedt, Deborah ; Colinet, Gilles ; Degré, Aurore in Milieux Poreux et Transferts Hydriques (in press)For the hydrological modeling of forested watersheds, the understanding of the forest hydrodynamic is essential. This study focusses on the hydrology of a Belgian forested plot with high stoniness and ... [more ▼]For the hydrological modeling of forested watersheds, the understanding of the forest hydrodynamic is essential. This study focusses on the hydrology of a Belgian forested plot with high stoniness and steep slope. The soil water content is monitored at several positions on the toposequence and at different depth. During rain events, peak in soil water content are observed in different depth depending on the position along the toposequence. [less ▲]Detailed reference viewed: 15 (1 ULg) Impact of the invasive Asian clam, Corbicula spp., on a large river ecosytemPigneur, Lise-Marie; Falisse, Elodie; Roland, Kathleen et alin Freshwater Biology (in press)During the past recent decades, Asiatic clams (Corbicula spp.) have spread spectacularly in several large European rivers. In the River Meuse, a transnational lowland river, an important chlorophyll a ... [more ▼]During the past recent decades, Asiatic clams (Corbicula spp.) have spread spectacularly in several large European rivers. In the River Meuse, a transnational lowland river, an important chlorophyll a decline has been recorded since the mid-2000s, which seems to be related to the invasion by these exotic bivalves. This study aimed at verifying that hypothesis, using clam density data from field surveys, water quality monitoring data, and a simulation model. Estimated Corbicula densities were between 50 and 900 individuals m-2, depending on the site. Using a maximum filtration rate per clam body mass of 0.086 m3 g C-1 day-1 at 20°C derived from the literature, we ran simulations with a non-stationary model to estimate the impact of the exotic bivalve on the river plankton and water quality. In the stretches where the invasive clams developed best, comparison with a clam-free scenario allowed estimating a 70 % phytoplankton biomass loss due to their filtration, leading to a 61 % loss of annual primary productivity. Model simulations also showed that zooplankton may have suffered as much as 75 % loss in terms of biomass. The simulations also point to substantial effects of the invasive Corbicula on the river oxygen budget and on nutrient cycling. We expect that, in the heavily regulated sectors of the river, the loss of planktonic production due to the invasive filter-feeders will negatively affect other suspension feeders and alter ecosystem function and productivity. [less ▲]Detailed reference viewed: 14 (3 ULg) IntroductionLevaux, Christophe in Belloi, Livio; Delville, Michel; Levaux, Christophe (Eds.) et al Boucle et répétition : musique, littérature, arts visuels (in press)Detailed reference viewed: 11 (0 ULg) On the asymptotic standard error of a class of robust estimators of ability in dichotomous item response modelsMagis, David in British Journal of Mathematical & Statistical Psychology (in press)In item response theory, the classical estimators of ability are highly sensitive to response disturbances and can return strongly biased estimates of the true underlying ability level. Robust methods ... [more ▼]In item response theory, the classical estimators of ability are highly sensitive to response disturbances and can return strongly biased estimates of the true underlying ability level. Robust methods were introduced to lessen the impact of such aberrant responses onto the estimation process. The computation of asymptotic (i.e., large sample) standard errors (ASE) for these robust estimators, however, has not been fully considered yet. This paper focuses on a broad class of robust ability estimators, defined by an appropriate selection of the weight function and the residual measure, for which the ASE is derived from the theory of estimating equations. The maximum likelihood (ML) and the robust estimators, together with their estimated ASE, are then compared through a simulation study. It is concluded that both the estimators and their ASE perform similarly in absence of response disturbances, while the robust estimator and its estimated ASE are less biased and outperform their ML counterparts in presence of response disturbances with large impact on the item response process. [less ▲]Detailed reference viewed: 14 (2 ULg) A review of the available data on lithostratigraphy, archaeostratigraphy and chronostratigraphyPirson, Stéphane ; Hauzeur, Anne ; Jungels, C. et alin Rougier, H.; Semal, P. (Eds.) Spy Cave. State of 125 Years of Pluridisciplinary Research on the Betche-aux-Rotches from Spy (Jemeppe-sur-Sambre, Province of Namur, Belgium) (in press)Detailed reference viewed: 3 (0 ULg) PrologueSemal, P.; Rougier, H.; Crevecoeur, I. et alin Rougier, H.; Semal, P. (Eds.) Spy Cave. State of 125 Years of Pluridisciplinary Research on the Betche-aux-Rotches from Spy (Jemeppe-sur-Sambre, Province of Namur, Belgium) (in press)Detailed reference viewed: 4 (0 ULg) A Schur Complement Method for DAE Systems in Power System Dynamic SimulationsAristidou, Petros ; Fabozzi, Davide; Van Cutsem, Thierry in Lecture Notes in Computational Science and Engineering (in press)This paper proposes a Schur complement-based Domain Decomposition Method to accelerate the time-domain simulation of large, non-linear and stiff Differential and Algebraic Equation systems stemming from ... [more ▼]This paper proposes a Schur complement-based Domain Decomposition Method to accelerate the time-domain simulation of large, non-linear and stiff Differential and Algebraic Equation systems stemming from power system dynamic studies. The proposed algorithm employs a star-shaped decomposition scheme and exploits the locality and sparsity of the system. The simulation is accelerated by the use of quasi-Newton schemes and parallel programming techniques. The proposed algorithm is implemented using the shared-memory parallel programming model and tested on a large-scale, realistic power system model showing significant speedup. [less ▲]Detailed reference viewed: 59 (13 ULg) A Super-Jupiter orbiting a late-type star: A refined analysis of microlensing event OGLE-2012-BLG-0406Tsapras, Y.; Choi, J.-Y.; Street, R. A. et alin Astrophysical Journal (in press)We present a detailed analysis of survey and follow-up observations of microlensing event OGLE-2012-BLG-0406 based on data obtained from 10 different observatories. Intensive coverage of the lightcurve ... [more ▼]We present a detailed analysis of survey and follow-up observations of microlensing event OGLE-2012-BLG-0406 based on data obtained from 10 different observatories. Intensive coverage of the lightcurve, especially the perturbation part, allowed us to accurately measure the parallax effect and lens orbital motion. Combining our measurement of the lens parallax with the angular Einstein radius determined from finite-source effects, we estimate the physical parameters of the lens system. We find that the event was caused by a $2.73\pm 0.43\ M_{\rm J}$ planet orbiting a $0.44\pm 0.07\ M_{\odot}$ early M-type star. The distance to the lens is $4.97\pm 0.29$\ kpc and the projected separation between the host star and its planet at the time of the event is $3.45\pm 0.26$ AU. We find that the additional coverage provided by follow-up observations, especially during the planetary perturbation, leads to a more accurate determination of the physical parameters of the lens. [less ▲]Detailed reference viewed: 13 (3 ULg) De Jacques Antoine aux Eperonniers : l'édition littéraire en Belgique au passé et au présent (seconde partie)Durand, Pascal ; Habrand, Tanguy in Textyles : Revue des Lettres Belges de Langue Française (in press)Second volet d'un article en deux parties portant sur l'édition littéraire contemporaine en Belgique, autour de deux maisons importantes : les éditions Jacques Antoine et les éditions des Eperonniers. La ... [more ▼]Second volet d'un article en deux parties portant sur l'édition littéraire contemporaine en Belgique, autour de deux maisons importantes : les éditions Jacques Antoine et les éditions des Eperonniers. La seconde partie de cette étude porte plus précisément sur la transition d'une maison à l'autre et sur la politique de la création contemporaine suivie par Lysiane d'Hayere aux Eperonniers. [less ▲]Detailed reference viewed: 16 (2 ULg) High-speed imaging use to predict spray retention on barley leavesBoukhalfa, Hassina dite Hafida ; Massinon, Mathieu ; Lebeau, Frédéric in Communications in Agricultural and Applied Biological Sciences (in press)Laboratory studies were conducted to validate the effectiveness of the use of high-speed imaging method to replace chemical nalysis by fluoremetrie. Measurements were performed with a high-speed camera ... [more ▼]Laboratory studies were conducted to validate the effectiveness of the use of high-speed imaging method to replace chemical nalysis by fluoremetrie. Measurements were performed with a high-speed camera coupled with a retro-LED lighting. Size and velocity of the drop were extracted by image analysis. Drop impact types were determined by the operator. Drops were produced with a flat-fan nozzle mounted on a movable ramp. Two surfactants (Break-Thru® S240 and Li700 ®) were sprayed on BBCH 12 barley leaves to highlight the effect of the reduction of surface tension. Relative volume proportions were computed within of an energy scale divided into 11 classes based on the Weber number. results are compared to the results of the chemical analysis by spectrofluerometry. [less ▲]Detailed reference viewed: 60 (20 ULg) compte rendu de : Eleanor DICKEY, The Colloquia of the Hermeneumata Pseudodositheana. Volume I. Colloquia Monacensia-Einsidlensia, Leidense-Stephani, and Stephani, Cambridge, Cambridge University Press, 2012. 1 vol. 21,5 x 28,5, XI-276 p. (CAMBRIDGE CLASSICAL TEXTS AND COMMENTARIES, 49). ISBN : 978-1-107-02010-8.Rochette, Bruno in Gnomon : Kritische Zeitschrift für die Gesamte Klassische Altertumswissenschaft (in press)Detailed reference viewed: 22 (0 ULg) Accuracy of asymptotic standard errors of the maximum and weighted likelihood estimators of proficiency levels with short testsMagis, David in Applied Psychological Measurement (in press)The maximum likelihood (ML) and the weighted likelihood (WL) estimators are commonly used to obtain proficiency level estimates with pre-calibrated item parameters. Both estimators have the same ... [more ▼]The maximum likelihood (ML) and the weighted likelihood (WL) estimators are commonly used to obtain proficiency level estimates with pre-calibrated item parameters. Both estimators have the same asymptotic standard error (ASE) that can be easily derived from the expected information function of the test. However, the accuracy of this asymptotic formula is uncertain with short tests when only a few items are administered. The purpose of this paper is to compare the ASE of these estimators to their exact values, evaluated at the proficiency level estimates. The exact SE is computed by generating the full exact sample distribution of the estimators, so its practical feasibility is limited to small tests (except under the Rasch model). A simulation study was conducted to compare the ASE and the exact SE of the ML and WL estimators, to the “true” SE (i.e., computed as the exact SE with the true proficiency levels). It is concluded that with small tests, the exact SEs are less biased and return smaller root mean squared error values than the asymptotic SEs, while as expected the two estimators return similar results with longer tests. [less ▲]Detailed reference viewed: 18 (4 ULg)