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See detailOndes de choc et tendinopathies : expérience clinique du CHU de Liège
Kaux, Jean-François ULg

Conference (2014, March 11)

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See detailOn the Identication of Symmetric N-qubit Maximally Entangled States
Baguette, Dorian ULg; Bastin, Thierry ULg; Martin, John ULg

Poster (2014, March 11)

Maximally entangled states can serve as a useful resource in many different contexts. It is therefore important to identify those states. Here we are interested in the identification of maximally ... [more ▼]

Maximally entangled states can serve as a useful resource in many different contexts. It is therefore important to identify those states. Here we are interested in the identification of maximally entangled states in the symmetric subspace of an N-qubit system. By maximally entangled states, we refer to symmetric states characterized by a one qubit reduced density matrix proportional to the identity. These states maximise various entanglement measures [1] such as von Neumann and Meyer-Wallach entropy and are unique up to LU in their SLOCC class [2]. We identify and characterize all maximally entangled symmetric states up to 4 qubits. We provide general conditions for a symmetric state with an arbitrary number of qubits to be maximally entangled and identify families of SLOCC classes which do not contain any maximally entangled states. [1] F. Verstraete, J. Dehaene, B. De Moor, Phys. Rev. A 68, 012103 (2003). [2] G. Gour, N. Wallach, N. J. Phys. 13, 073013 (2011) [less ▲]

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See detailMédias et acteurs économiques en Europe. De la crise du journalisme aux discours de crise
Geuens, Geoffrey ULg

Conference given outside the academic context (2014)

Detailed reference viewed: 21 (12 ULg)
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See detailComputational homogenization of cellular materials capturing micro-buckling, macro-localization and size effects
Nguyen, Van Dung ULg

Doctoral thesis (2014)

The objective of this thesis is to develop an efficient multi-scale finite element framework to capture the macroscopic localization due to the micro-buckling of cell walls and the size effect phenomena ... [more ▼]

The objective of this thesis is to develop an efficient multi-scale finite element framework to capture the macroscopic localization due to the micro-buckling of cell walls and the size effect phenomena arising in structures made of cellular materials. Under the compression loading, the buckling phenomenon (so--called micro--buckling) of the slender components (cell walls, cell faces) of cellular solids can occur. Even if the tangent operator of the material of which the micro--structure is made, is still elliptic, the presence of the micro--buckling can lead to the loss of ellipticity of the resulting homogenized tangent operator. In that case, localization bands are formed and propagate in the macroscopic structure. Moreover, when considering a cellular structure whose dimensions are close to the cell size, the size effect phenomenon cannot be neglected since deformations are characterized by a strain gradient. On the one hand, a classical multi-scale computational homogenization scheme (so-called first-order scheme) looses accuracy with the apparition of the macroscopic localization or the high strain gradient arising in cellular materials because the underlying assumption of the local action principle, in which the stress state on a macroscopic material point depends only on the strain state at that point, is no--longer suitable. On the other hand, the second-order multi-scale computational homogenization scheme proposed by Kouznetsova exhibits a good ability to capture such phenomena. Thus this second--order scheme is improved in this thesis with the following novelties so that it can be used for cellular materials. First, at the microscopic scale, the periodic boundary condition is used because of its efficiency. As the meshes generated from cellular materials exhibit a large void part on the boundaries and are not conforming in general, the classical enforcement based on the matching nodes cannot be applied. A new method based on the polynomial interpolation without the requirement of the matching mesh condition on opposite boundaries of the representative volume element (RVE) is developed. Next, in order to solve the underlying macroscopic Mindlin strain gradient continuum of this second-order scheme by the displacement-based finite element framework, the presence of high order terms (related to the higher stress and strain) leads to many complications in the numerical treatment. Indeed, the resolution requires the continuities not only of the displacement field but also of its first derivatives. This work uses the discontinuous Galerkin (DG) method to weakly impose these continuities. This proposed second--order DG--based FE2 scheme appears to be easily integrated into conventional parallel finite element codes. Finally, the proposed second-order DG-based FE2 scheme is used to model cellular materials. As the instability phenomena are considered at both scales, the path following technique is adopted to solve both the macroscopic and microscopic problems. The micro--buckling leading to the macroscopic localization and the size effect phenomena can be captured within the proposed framework. [less ▲]

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See detailCorsican seagrass detritus: An opportune shelter or a copepod Eldorado?
Mascart, Thibaud ULg; Lepoint, Gilles ULg; Remy, François ULg et al

Poster (2014, March 07)

Seagrass ecosystems are extensive beds of marine flowering plants bordering tropical and temperate coastal regions. They play an important role in maintaining biological productivity and bio-geochemical ... [more ▼]

Seagrass ecosystems are extensive beds of marine flowering plants bordering tropical and temperate coastal regions. They play an important role in maintaining biological productivity and bio-geochemical cycles in the sea and support higher diversity and abundance of fauna in comparison to adjacent non-vegetated areas. The seagrass meadow primary production can be directly consumed through herbivory but the majority of the plant material falls on the sea floor during the autumnal leaf senescence. The leaf litter then degrades within the meadow or accumulates with other micro- and macrophytodetritus to form detritus accumulations on the adjacent non-vegetated sand patches. These exported accumulations are quite dynamic in relation to seafloor geomorphology and local hydrodynamics. Thus, the detritus accumulations are an easily disturbed ephemeral environment with one large influx a year. Consequently the physico-chemical characteristics can change very fast and impact the sheltering capacity and food supply present. Nonetheless, fishes, macrofauna and meiofauna are omnipresent throughout the year. In our study site along the shore of N-W Corsica, Posidonia oceanica seagrass meadows are characterised by substantial detritus accumulations. The present study aimed to analyse the biodiversity of the copepod species communities (Crustacea, Copepoda) in those detritus accumulations. The results showed that the copepod detritus community consisted of a mixture of species that are also found in adjacent habitats (seagrass meadow, sediment, epilithic habitats, water column). Each adjacent habitat is characterised by organisms that are morphologically adapted to the specific features of that habitat. The majority of copepods are epiphytic (order Harpacticoida), that occur typically on seagrass leaves and macroalgae. Other species are planktonic (orders Cyclopoida and Calanoida) and some were benthic (order Harpacticoida), known from the nearby sediment. A minority of the copepod community were parasitic on fish or invertebrate (order Siphonostomatoida). In order to clarify their origin, we assume that passive transport by currents plays a significant role next to the active migration from the anoxic sediments under the detritus. For sure they also reproduce within the detritus packages as we found many nauplii, copepodites and gravid females. The above mentioned suggestions cannot explain such high density of copepods by themselves. Other attraction mechanisms are needed to explain the important amount of planktonic and epiphytic species with good swimming ability, such as higher food accessibility. In the detritus no plant-defence mechanisms are present anymore and a lot of micro-organisms and thus potential food sources are present. Furthermore, the dense detritus package provides shelter and protection from potential predators. Subsequently we may consider the detritus accumulations as a copepod species-specific opportune Eldorado for sheltering, nursing and feeding. [less ▲]

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See detailA framework for using decision-support tools at various spatial scales for the management of irrigated agriculture in semi-arid West-Africa
Wellens, Joost ULg

Doctoral thesis (2014)

The Kou watershed, situated in the Southwestern part of Burkina Faso, has succumbed since a couple of decades to a typical theater play of anarchistic water management. With its 1.800 km², this small ... [more ▼]

The Kou watershed, situated in the Southwestern part of Burkina Faso, has succumbed since a couple of decades to a typical theater play of anarchistic water management. With its 1.800 km², this small watershed includes the second largest city of Burkina Faso (Bobo-Dioulasso), a former state run irrigated rice scheme and several informal agricultural zones. Despite the abundance of water resources, most water users find themselves regularly faced with shortages due to an increase in population and low irrigation efficiencies. Local stakeholders are hence in need of easy to use and low-cost decision support tools for the monitoring and exploitation of the water resources at different spatial and user levels. A top-to-bottom string of adapted water management tools has successfully been installed to tackle the problems: from watershed (top) to field level (bottom), not to mention the 1200 ha irrigation scheme. Land use maps have been derived from satellite and aerial images. Combined with data from a network of hydrologic gauging stations, regional water use maps were established. Hot spots in inefficient water use could be geographically identified and more detailed actions undertaken. Scheme Information Management Information System (SIMIS) was put in place for the management of the regions irrigated rice scheme. A more equitable distribution for the ever diminishing available water resources could be elaborated. A public-private partnership was installed to guarantee its sustainability. Day to day water use on irrigated plots was monitored by soil humidity and crop canopy measurements. A simple field-crop-water balance model AquaCrop was calibrated and validated, and is used by extension workers to draft optimal irrigation charts. Each tool is applied independently, requiring only limited data; but their combined results contribute to an improved integrated water management. [less ▲]

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See detailModes intentionnels
Dewalque, Arnaud ULg

Conference (2014, March 07)

Je dresse le bilan de la situation des recherches actuelles en théorie de la perception (entre représentationalisme et relationalisme), et je suggère que la voie d'investigations la plus prometteuse est l ... [more ▼]

Je dresse le bilan de la situation des recherches actuelles en théorie de la perception (entre représentationalisme et relationalisme), et je suggère que la voie d'investigations la plus prometteuse est l'intentionalisme modal. D'après l'intentionalisme modal, un état mental est individualisé par son contenu intentionnel et par son mode intentionnel. En m'appuyant sur la méthode descriptive de Franz Brentano, je propose alors un argument en faveur de cette conception: l'argument de la complétude. [less ▲]

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Peer Reviewed
See detailEquations fantaisistes : l'argent comme ressort burlesque dans l'œuvre de Pierre La Police
Belloi, Livio ULg

Conference (2014, March 06)

Conçue comme une vaste parodie du discours médiatique en général et de la presse quotidienne en particulier, la série "Véridique !" (Cornélius, 1999-2002) du dessinateur français Pierre La Police met ... [more ▼]

Conçue comme une vaste parodie du discours médiatique en général et de la presse quotidienne en particulier, la série "Véridique !" (Cornélius, 1999-2002) du dessinateur français Pierre La Police met volontiers en scène des questions ou des rapports d’argent. Le plus souvent lié à la sphère politique, le thème de l’argent autorise l’auteur à jeter un regard narquois et particulièrement acéré sur des événements qui firent grand bruit dans la France des années 1990 (l’affaire Roland Dumas, le scandale de l’ARC, l’affaire des emplois fictifs à la ville de Paris, etc.). Ma communication étudie au plus près les mises en scène de l’argent dans l’œuvre de Pierre La Police et s'efforce de porter au jour les véritables équations mises au point à cet égard par l’auteur. Toutes à leur manière, ces équations concourent à faire du thème de l’argent un ressort burlesque à part entière ; elles participent également d’une esthétique générale de la distorsion et de l’approximation, qui est comme la marque de fabrique de Pierre La Police. [less ▲]

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See detailEarly neuropsychological detection of Alzheimer's disease
Bastin, Christine ULg

Conference (2014, March 06)

Considering that brain pathology due to Alzheimer’s disease starts many years before the clinical symptoms become evident, subtle cognitive changes may exist already in the predementia phase. Different ... [more ▼]

Considering that brain pathology due to Alzheimer’s disease starts many years before the clinical symptoms become evident, subtle cognitive changes may exist already in the predementia phase. Different approaches have been used to detect initial cognitive impairments indicative of Alzheimer’s disease. One approach is the assessment of the predictive power of neuropsychological tools in characterizing patients with stable mild cognitive impairment (MCI) versus MCI patients who subsequently develop Alzheimer’s disease. Another approach is the longitudinal evaluation of large cohorts of older adults in population-based studies. Findings from several studies suggest that a memory test that ensures deep encoding of information and assesses retrieval with free as well as cued recall is a useful tool to distinguish patients at an early stage of Alzheimer disease from MCI non-converters. Impaired semantic memory has also been proposed as a neuropsychological marker of predementia Alzheimer’s disease. Beyond the memory domain, category verbal fluency has been shown to predict progression to Alzheimer’s disease. Moreover, combining neuropsychological scores of memory and executive functions and neuroimaging data allows a better discrimination between stable MCI and converters than neuroimaging data alone. Altogether, it is possible to detect cognitive changes that are predictive of the typical form of probable Alzheimer’s disease already in the predementia stage. Such at risk people are thought to be the best target for therapeutic interventions. [less ▲]

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See detailL'utilisation de la spectrométrie (NIR) et l’imagerie hyperspectrale (NIR-HIS) proche infrarouge pour étudier la composition chimique et botanique de des fourrages
Dale, Laura-Monica ULg

Doctoral thesis (2014)

Forage quality or nutritive value is related to chemical composition, which can be determinated by laboratory methods. The NIR technique in comparison with classical methods is non-destructive, non ... [more ▼]

Forage quality or nutritive value is related to chemical composition, which can be determinated by laboratory methods. The NIR technique in comparison with classical methods is non-destructive, non-polluting, fast and relatively inexpensive per analysis. Investigations on nutritional quality of Carpathians Apuseni Mountains (Romania) grasslands are rarely performed with NIR technique. Therefore, the objective of the thesis was to develop non-destructive methods for evaluating the quality of feed originating from the Gârda area of the Carpathians Apuseni Mountains (Romania) potentially and to similar grassland arround the world. The first task was to study the potential of NIR spectroscopy for building a spectral database for forage quality based on a large collection of semi-natural grassland samples, using a ‘local’ calibration model built by the Walloon Agricultural Research Centre (CRA-W), in Belgium, to determine various parameters (e.g., protein, dry matter, ash, fibre, fat, aNDFom, ADF, lignin, digestibility, crude energy) from samples collected worldwide, outside Romania. The second task was to develop calibration models for an NIR-HSI system, which involved larger spectral data registration as an image. Until now, analyses to determine plant species were based on botanical composition evaluation, including visual observation, which is a subjective method involving identifying plants directly in the field. Distinguishing samples of pure grassland species can be time consuming, and it was therefore decided to build a spectral database of pure samples and then discriminate these samples into binary and ternary artificial sample mixtures. The main objective of these tasks was to identify the botanical families to which the samples belonged (Poaceae, Fabaceae and Other Botanical Families [OBF]). The focus was not on quantity monitoring, but rather on determining forage quality from stationary experiments in the grasslands. To conclude, this research has shown that it is possible to develop calibration models not only for quality assessment, but also for sample discrimination in dry powder samples. It was intended, that the mathematical models constructed and the database obtained, would be used for future research. [less ▲]

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See detailA vision-based autonomous inter-row weeder
Krishna Moorthy Parvathi, Sruthi Moorthy ULg; Detry, Renaud ULg; Boigelot, Bernard ULg et al

Conference (2014, March 05)

Autonomous robotic weed destruction plays a significant role in crop production as it automates one of the few unmechanized and drudging tasks of agriculture i.e. manual weed destruction. Robotic ... [more ▼]

Autonomous robotic weed destruction plays a significant role in crop production as it automates one of the few unmechanized and drudging tasks of agriculture i.e. manual weed destruction. Robotic technology also contributes to long-term sustainability with both economic and environmental benefits, by minimising the current dependency on chemicals. The aim of this study is to design a small low-cost versatile robot allowing the destruction of weeds that lie between the crop rows by navigating in the field autonomously and using a minimum of a priori information of the field. For the robot to navigate autonomously, necessary and sufficient information can be supplied by a machine vision system. One important issue with the application of machine vision is to develop a system that recognises the crop rows accurately and robustly which is tolerant to problems such as crops at varying growth stages, poor illumination conditions, missing crops, high weed pressure, etc. Aiming at accurate and robust real-time guidance of autonomous robot through the field, the plethora of image processing algorithms like Ostu’s threshold method and hough transform will be explored for two main processes namely the image segmentation and crop row detection respectively. In order to overcome the issue of large variabilities encountered in agriculture such as varying weather conditions, intelligent stochastic data fusion and machine learning algorithms will be used to combine data from heterogeneous sensors. Besides crop row detection, other major challenges foreseen are: mapping the unknown geometry of the field, high-level planning of efficient and complete coverage of the field, controlling the low-level op- erations of the robot, and ensuring security. Specialised sensors such as GPS will be considered to generate the map of the field enabling Simultaneous Localisation And Mapping (SLAM) in real time on a mobile platform. The generated map will be exploited along with the sensorial in- formation from crop row detection to efficiently plan and execute the guidance of the robot au- tonomously in the field, thereby enabling weed elimination. [less ▲]

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See detailPeriodicity of the algebras O_n and O_{p,q}
Kreusch, Marie ULg

E-print/Working paper (2014)

We study a series of complex (resp. real) non-associative algebras O_n (resp. O_{p,q}) characterized by a cubic form over the field Z_2. Continuing the work of classification, we establish a periodicity ... [more ▼]

We study a series of complex (resp. real) non-associative algebras O_n (resp. O_{p,q}) characterized by a cubic form over the field Z_2. Continuing the work of classification, we establish a periodicity for the algebras O_n and O_{p,q} similar to that of the Clifford algebras Cl_n and Cl_{p,q} excluded the exceptional algebras O_{n,0} and O_{0,n}. [less ▲]

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See detailChemical Hydrolysis of Fagus sylvatica Wood: Dilute Acid vs. Alkaline Treatment
Miazek, Krystian ULg; Goffin, Dorothée ULg; Richel, Aurore ULg

Poster (2014, March 05)

Lignocellulosic biomass, found in a large variety of plants such as coniferous trees (Softwood), broad leaved trees (Hardwood), grasses and agricultural or food residues, is the most abundant source of ... [more ▼]

Lignocellulosic biomass, found in a large variety of plants such as coniferous trees (Softwood), broad leaved trees (Hardwood), grasses and agricultural or food residues, is the most abundant source of molecules required for production of biofuels and high value - added products. Lignocellulose is composed of three polymers: cellulose, hemicellulose and lignin. Cellulose is a non-branched polymer consisting of glucoses (hexoses). Hemicellulose is a complex carbohydrate containing pentoses (mainly xyloses in the case of Hardwood, grasses and agricultural wastes) or hexoses (usually mannoses in the case of Softwood) as the main sugars. Lignin is a biopolymer with aromatic alcohols as basic monomeric units. Cellulose chains are arranged in bundles and interlinked with hemicellulose. Lignin is cross-linked with hemicellulose and occupies space between cellulose bundles. Due to complex polymeric structure, lignocellulosic materials are resistant to hydrolysis. A number of treatment methods (mechanical, chemical, biochemical) is implemented to successfully hydrolyse lignocellulose. Amongst chemical methods harnessed to break lignocellulose structure, dilute acid and alkaline treatments are commonly mentioned, as the most efficient ones. The objective of this study was to evaluate the effect of dilute acid and alkaline treatment on hydrolysis rate of polymeric components in Fagus sylvatica wood. Fagus sylvatica also known as common beech is a broad leaved, deciduous tree that belongs to the family of Fagaceae, widely spread in Europe. Beech wood was determined to contain 48 % glucose, 18 % xylose and 20 % Klason lignin in its dry material. Results of this study showed that 1 h hydrolysis at 100 °C with the use of 3 % H2SO4 resulted in 71 % removal of xylose and 4 % removal of glucose with Klason lignin remained intact. Additionally, the presence of sugar degradation products: 2 - furfural and hydroxymethylfurfural was detected in dilute acid hydrolysate. Release of 2 - furfural and hydroxymethylfurfural from beech wood was determined as 0.03 % and 0.1 %, respectively. On the other hand, 1 h hydrolysis at 100 °C with the use of 7 % NaOH caused 59 % xylose removal and 11 % removal of Klason lignin with no effect on glucose. Dilute acid hydrolysis proved to be more efficient in removing xylose, but alkaline hydrolysis additionally showed to remove Klason lignin. [less ▲]

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See detailAn efficient standard error formula for the weighted likelihood estimator of ability
Magis, David ULg

Scientific conference (2014, March 04)

The weighted likelihood estimator (WLE; Warm, 1989) has become a very popular ability estimator in item response theory. It was developed to basically cancel the estimation bias of the maximum likelihood ... [more ▼]

The weighted likelihood estimator (WLE; Warm, 1989) has become a very popular ability estimator in item response theory. It was developed to basically cancel the estimation bias of the maximum likelihood estimator (MLE) with short tests. However, some uncertainty remains about its standard error formula. Warm (1989) established the asymptotic equivalence of the standard errors of both MLE and WLE, but there exists actually various practical formulas for the latter (Magis & Raîche, 2012; Nydick, 2013; Partchev, 2012; Warm, 2007), leading obviously to confusion. The purpose of this talk is to briefly sketch a general approach to derive a first-order approximation of the standard error of the WLE. Based on asymptotic adjustments of the law of large numbers and central limit theorem, a simple formula is derived. The efficiency of the latter is compared to aforementioned formulas by means of a simulation study under Rasch modeling. Preliminary results indicate that the derived formula has lower bias and RMSE than any other competing formula, especially with short tests. All formulas behave similarly with longer tests, as expected. [less ▲]

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See detailHistoire des musiques africaines-américaines; partim LE BLUES après 1945
Sacré, Robert ULg

Conference given outside the academic context (2014)

Après 1945: multiplication des petites compagnies de disques indépendantes- Electrification des instruments ; migrations noires Sud-Nord; maintien des styles ruraux (en léthargie) - développement des ... [more ▼]

Après 1945: multiplication des petites compagnies de disques indépendantes- Electrification des instruments ; migrations noires Sud-Nord; maintien des styles ruraux (en léthargie) - développement des styles urbains (Memphis, Chicago, Houston, New Orleans,...Louisiane, Californie,...) Désaffection des noirs US pour le blues; blues revival en Europe; le blues aujourd'hui [less ▲]

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See detailThe yellow hypergiant HR 5171 A: Resolving a massive interacting binary in the common envelope phase
Chesneau, O.; Meilland, A.; Chapellier, E. et al

in Astronomy and Astrophysics (2014), 563

Context. Only a few stars are caught in the very brief and often crucial stages when they quickly traverse the Hertzsprung-Russell diagram, and none has yet been spatially resolved in the mass transfer ... [more ▼]

Context. Only a few stars are caught in the very brief and often crucial stages when they quickly traverse the Hertzsprung-Russell diagram, and none has yet been spatially resolved in the mass transfer phase. Aims: We initiated long-term optical interferometry monitoring of the diameters of massive and unstable yellow hypergiants (YHG) with the goal of detecting both the long-term evolution of their radius and shorter term formation of a possible pseudo-photosphere related to proposed large mass-loss events. Methods: We observed HR 5171 A with AMBER/VLTI. We also examined archival photometric data in the visual and near-IR spanning more than 60 years, as well as sparse spectroscopic data. Results: HR 5171 Aexhibits a complex appearance. Our AMBER data reveal a surprisingly large star for a YHG R∗ = 1315 ± 260R⊙ (or ~6.1 AU) at the distance of 3.6 ± 0.5 kpc. The source is surrounded by an extended nebulosity, and these data also show a large level of asymmetry in the brightness distribution of the system, which we attribute to a newly discovered companion star located in front of the primary star. The companion's signature is also detected in the visual photometry, which indicates an orbital period of Porb = 1304 ± 6 d. Modeling the light curve with the NIGHTFALL program provides clear evidence that the system is a contact or possibly over-contact eclipsing binary. A total current system mass of 39^+40_-22 M⊙ and a high mass ratio q ≥ 10 is inferred for the system. Conclusions: The low-mass companion of HR 5171 is very close to the primary star that is embedded within its dense wind. Tight constraints on the inclination and vsini of the primary are lacking, which prevents us from determining its influence precisely on the mass-loss phenomenon, but the system is probably experiencing a wind Roche-Lobe overflow. Depending on the amount of angular momentum that can be transferred to the stellar envelope, HR 5171 A may become a fast-rotating B[e]/luminous blue variable/Wolf-Rayet star. In any case, HR 5171 A highlights the possible importance of binaries for interpreting the unstable YHGs and for massive star evolution in general. [less ▲]

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See detailImpacts of earthworms on soil components and dynamics. A review
Lemtiri, Aboulkacem ULg; Colinet, Gilles ULg; Alabi, Taofic ULg et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2014), 18

Earthworm populations are important decomposers contributing to aggregate formation and nutrient cycling processes involving nitrogen cycles, phosphorus and carbon. They are known to influence soil ... [more ▼]

Earthworm populations are important decomposers contributing to aggregate formation and nutrient cycling processes involving nitrogen cycles, phosphorus and carbon. They are known to influence soil fertility by participating to important processes in soil such as soil structure regulation and organic matter dynamics. Earthworms also modify the microbial communities through digestion, stimulation and dispersion in casts. Consequently, changes in the activities of earthworm communities, as a result of soil management practices, can also be used as indicators of soil fertility and quality. It is therefore important to understand how earthworm communities affect soil dynamics. This review adresses the current state of knowledge on earthworm’s impacts on soil structure and soil organic matter (carbon, nitrogen, and phosphorus) dynamics, with special emphasis on the effects of land management practices on earthworm communities. [less ▲]

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See detailAn astronomical survey conducted in Belgium
Nazé, Yaël ULg; Fontaine, Sébastien ULg

in Physics Education (2014), 49

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 ▲]

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See detailMode identification based on time-series spectrophotometry for the bright rapid sdB pulsator EC 01541-1409
Randall, Suzanna K; Fontaine, Gilles; Geier, Stephan et al

in Astronomy and Astrophysics (2014), 563

We present an analysis of time-resolved spectrophotometry gathered with FORS/VLT for the rapidly pulsating hot B subdwarf EC 01541-1409 with the aim of identifying the degree index ℓ of the larger ... [more ▼]

We present an analysis of time-resolved spectrophotometry gathered with FORS/VLT for the rapidly pulsating hot B subdwarf EC 01541-1409 with the aim of identifying the degree index ℓ of the larger amplitude modes. This mode identification can be extremely useful in detailed searches for viable asteroseismic models in parameter space, and can be crucial for testing the validity of a solution a posteriori. To achieve it, we exploit the ℓ-dependence of the monochromatic amplitude, phase, and velocity-to-amplitude ratio of a mode as a function of wavelength. We use the ℓ-sensitive phase lag between the flux perturbation and the radial velocity as an additional diagnostic tool. On this basis, we are able to unambiguously identify the dominant 140.5 s pulsation of our target as a radial mode, and the second-highest amplitude periodicity at 145.8 s as an ℓ = 2 mode. We further exploit the exceptionally high-sensitivity data that we gathered for the dominant mode to infer modal properties that are usually quite difficult to estimate in sdB pulsators, namely the physical values of the dimensionless radius, temperature, and surface gravity perturbations. [less ▲]

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See detailEmbodying the divine: herms in Greek vase-painting
Collard, Hélène ULg

Conference (2014, March)

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