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See detailOrbital, spin state and thermophysical characterization of near-Earth asteroid (3200) Phaethon
Hanus, Josef; Delbo, Marco; Vokrouhlický, D. et al

in Astronomy and Astrophysics (2016)

The near-Earth asteroid (3200) Phaethon is an intriguing object: its perihelion is only at 0.14 au and is associated with the Geminid meteor stream. We aim to use all available disk-integrated optical ... [more ▼]

The near-Earth asteroid (3200) Phaethon is an intriguing object: its perihelion is only at 0.14 au and is associated with the Geminid meteor stream. We aim to use all available disk-integrated optical data to derive reliable convex shape model of Phaethon. By interpreting the available space- and ground-based thermal infrared data and Spitzer spectra using a thermophysical model, we also aim to further constrain its size, thermal inertia, and visible geometric albedo. We apply the convex inversion method to the new optical data obtained by six instruments together with the already existing observations. The convex shape model is then used as an input for the thermophysical modeling. We also study the long-term stability of Phaethon’s orbit and spin axis by a numerical orbital and rotation-state integrator We present a new convex shape model and rotational state of Phaethon – sidereal rotation period of 3.603958(2) h and ecliptic coordinates of the preferred pole orientation of (319◦ , −39◦) with a 5◦ uncertainty. Moreover, we derive its size (D=5.1±0.2 km), thermal inertia (Γ=600±200 J m-2s -1/2K -1), geometric visible albedo (pV=0.122±0.008), and estimate the macroscopic surface roughness. We also find that the Sun illumination at the perihelion passage during past thousands of years is not connected to a specific area on the surface implying non-preferential heating. [less ▲]

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See detailÉtude de cas : le site Gamekult (période « post-premium »)
Krywicki, Boris ULg

Scientific conference (2016, May 18)

Ce pure player dédié à l’actualité généraliste du jeu vidéo reflète un positionnement assez hybride au sein du champ de la presse vidéoludique numérique. Tout en restant chevillé au traitement classique « ... [more ▼]

Ce pure player dédié à l’actualité généraliste du jeu vidéo reflète un positionnement assez hybride au sein du champ de la presse vidéoludique numérique. Tout en restant chevillé au traitement classique « news – previews – tests » de ce type de médias, il cherche à se montrer plus intransigeant que ses concurrents. Le lancement de son modèle économique « premium », qui fait basculer une partie des articles proposés par le portail en accès payant, s’accompagne d’une série de discours réflexifs sur le métier de journaliste de jeu vidéo et ses pratiques endogamiques, que l’équipe ne manque pas de montrer du doigt. Ainsi, les contenus éditoriaux de Gamekult s’inscrivent dans le suivi de l’actualité « chaude » du jeu vidéo, mais cherchent à paraître plus pertinents ou plus avertis que les propositions des autres sites par toute une série de stratégies rédactionnelles et oratoires. Le choix, loin de s’avérer anodin, de mettre en scène l’équipe de la rédaction au sein d’un documentaire, à l’occasion des 15 ans du site, lui confère un espace pour illustrer ce qu’elle présente à plusieurs reprises comme un « combat ambitieux ». De la même manière, nous pourrons observer comment, par une kyrielle d’adresses à sa destination plus ou moins subtiles, Gamekult performe son lectorat, lui bâtit un ouitllage clé-en-main pour se définir en tant que lecteur-partisan des valeurs proposées par le portail et, par effet communautaire, opposé à la concurrence. L’information que construit Gamekult s’appuie énormément sur une vision du jeu vidéo et de son industire qui, à plusieurs égards, vient justifier et légitimer le parti-pris du portail en termes de modèle économique. Ce cas particulier permettra de résumer les enjeux des adresses aux lecteurs de la critique culturelle et, par extension, d’interroger les limites de l’instrumentalisation des récepteurs en tant que porte-étendards d’une communauté de valeurs définies par l’orientation politico-économique d’un média. Il illustrera comment l’accumulation de petits clins d’œil, parfois triviaux d’apparence, permettent de convaincre, sur le long terme, de la bonne foi des acteurs d’un milieu, par opposition aux déviances d’autres, et de la glorification d’un ethos à l’aune de l’éthique, pourtant relative. [less ▲]

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See detailDébats autour du concept de type en typologie des langues
Lttr13; Badir, Sémir ULg; Polis, Stéphane ULg et al

Conference (2016, May 18)

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See detailL'ordinateur dans la littérature allemande au tournant du millénaire
Dupont, Bruno ULg

Poster (2016, May 18)

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See detailConceptualisation de l’espace public dans la Théorie critique
Glorie, Caroline ULg

Conference (2016, May 18)

Mon projet de recherche consiste en une étude généalogique et critique des conceptualisations de l’espace public qu’on peut trouver dans la Théorie critique. Il vise à problématiser les formes du public à ... [more ▼]

Mon projet de recherche consiste en une étude généalogique et critique des conceptualisations de l’espace public qu’on peut trouver dans la Théorie critique. Il vise à problématiser les formes du public à l’aide de Walter Benjamin, Oskar Negt et Hans-Magnus Enzensberger. Je procéderai selon deux axes. Premièrement, il s’agira de réaliser une généalogie philosophique du concept d’espace public d’après la Théorie critique de Benjamin, Negt et Enzensberger. D’une part, une telle généalogie doit être effectuée en regard du concept habermassien d’espace public, en particulier en ce qui concerne la problématisation negtienne d’un espace public oppositionnel. D’autre part, cette étude ne pourra être réalisée sans une attention aux formes et conceptualisations historiques de l’espace public au cours des XIXème et XXème siècles : les salons littéraires, la presse, le développement de la radio, etc. Dans le cadre du projet ARC « Humanités critiques », une attention particulière sera accordée à la forme revue qui, chez les trois auteurs concernés, peut être considérée comme un lieu primordial de théorisation et de conceptualisation de l’espace public. Deuxièmement, sur la base de cette autre lignée de la Théorie critique, il s’agira de construire une problématisation de l’espace public. Mon hypothèse est la suivante : l’approche critique proposée par Benjamin, Negt et Enzensberger consiste à prendre en considération une dialectique toujours à l’œuvre entre différents espaces publics, ainsi qu’entre des formes hétérogènes qu’ils peuvent prendre. [less ▲]

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See detailGérer l’Etat belge, pas la S.A. Belgique
Delvenne, Pierre ULg; Rossignol, Nicolas ULg

Article for general public (2016)

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See detailChaotic Bohmian trajectories for stationary states
Cesa, Alexandre ULg; Martin, John ULg; Struyve, Ward

Poster (2016, May 18)

We study the possibility of chaos for the Bohmian dynamics when the wave function is stationary. Examples of stationary wave functions are given for which there is chaos, as demonstrated by numerical ... [more ▼]

We study the possibility of chaos for the Bohmian dynamics when the wave function is stationary. Examples of stationary wave functions are given for which there is chaos, as demonstrated by numerical computations, for one particle moving in 3 spatial dimensions and for two and three entangled particles in 2 dimensions. What is important for the amount of chaos is the overall complexity of the wave function. Some simple measures that partly capture the complexity of the wave function are considered: the participation ratio and different measures of entanglement. We find that these measures often tend to correlate to the amount of chaos. However, the correlation is not perfect, because the measures do not depend on the intrinsic complexity of the states of a given basis. [less ▲]

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See detailDevelopment of a hydrogen maser in the TE111 mode
Van Der Beken, Emeline ULg; Léonard, Daniel; Counet, Arnaud et al

Poster (2016, May 18)

We present the recent progress in the development of a hydrogen maser in the unusual TE111 mode. In contrast to standard hydrogen maser that exploits the TE011 mode, the TE111 mode allows one to design ... [more ▼]

We present the recent progress in the development of a hydrogen maser in the unusual TE111 mode. In contrast to standard hydrogen maser that exploits the TE011 mode, the TE111 mode allows one to design hydrogen masers with significant reduced dimensions which represents a huge benefit for space applications and in particular for the global positioning system. We present in details the different parts of our model : cavity with a thin Teflon sheet, magnetic shielding, temperature control of the maser... [less ▲]

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See detailA New Approach for the Characterization of Organic Residues from Stone Tools Using GC×GC-TOFMS
Perrault, Katelynn ULg; Stefanuto, Pierre-Hugues ULg; Dubois, Lena ULg et al

in Separations (2016), 3(2), 16

Headspace solid-phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS) have traditionally been used, in combination with other analyses, for the chemical characterization of ... [more ▼]

Headspace solid-phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS) have traditionally been used, in combination with other analyses, for the chemical characterization of organic residues recovered from archaeological specimens. Recently in many life science fields, comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (GC×GC-TOFMS) has provided numerous benefits over GC-MS. This study represents the first use of HS-SPME-GC×GC-TOFMS to characterize specimens from an experimental modern reference collection. Solvent extractions and direct analyses were performed on materials such as ivory, bone, antlers, animal tissue, human tissue, sediment, and resin. Thicker film column sets were preferred due to reduced column overloading. The samples analyzed by HS-SPME directly on a specimen appeared to give unique signatures and generally produced a higher response than for the solvent-extracted residues. A non-destructive screening approach of specimens may, therefore, be possible. Resin and beeswax mixtures prepared by heating for different lengths of time appeared to provide distinctly different volatile signatures, suggesting that GC×GC-TOFMS may be capable of differentiating alterations to resin in future studies. Further development of GC×GC-TOFMS methods for archaeological applications will provide a valuable tool to uncover significant information on prehistoric technological changes and cultural behavior. [less ▲]

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See detailAnticoherence of spin states with point-group symmetries
Baguette, Dorian ULg; Damanet, François ULg; Giraud, Olivier et al

Poster (2016, May 18)

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See detailSuper- and subradiance from indistinguishable atoms with quantized motion
Damanet, François ULg; Braun, Daniel; Martin, John ULg

Poster (2016, May 18)

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See detailCan tropical basil be integrated in vegetable crop pest management?
Yarou, Boni Barthélémy ULg; Verheggen, François ULg; Heuskin, Stéphanie ULg et al

Poster (2016, May 17)

To address human and environmental health issues related to the use of synthetic pesticides, it is important to explore other ecological pest management approaches. Within this context, a study was ... [more ▼]

To address human and environmental health issues related to the use of synthetic pesticides, it is important to explore other ecological pest management approaches. Within this context, a study was conducted to evaluate the toxic and repellent effect of Ocimum gratissimum L. (Lamiaceae) on Myzus persicae S. (Aphididae). The toxicity of O. gratissimum essential oil (EO) was evaluated on M. persicae comparing 3 concentrations (0.001%; 0.01% and 0.1%) to a control (15% sucrose). Mortality rate and fecundity were assessed for each concentration. The observations were made daily, for 4 days, on 12 replicates per treatment. To test the repellent effect of O. gratissimum plants, 2 treatments were compared: a group of 8 Amaranthus cruentus L. (Amaranthaceae) plants with 1 plant of O. gratissimum in the middle and a group of 9 A. cruentus plants (control). The distribution of aphids was analyzed 12 days after the middle plant infestation (20 aphids per plant) for each treatment (6 replicates per treatment). O. gratissimum EO was found toxic from a concentration of 0.01%, with a mortality rate of 34% versus 12% for the control ; The fecundity felt from 30 larvae after 4 days (control) to 15 larvae for the 3 doses of the EO. The analysis with the generalized linear mixed model with Poisson error distribution followed by Turkey test (5 %) showed that EO is significantly more toxic than the control, both for mortality and fecundity (p <0.001). In association test, the population of M. persicae (15 aphids per plant) was significantly (p<0,001) lower when A. cruentus plants was associated with O. gratissimum plant than with the control (22 aphids per plant). Furthermore, the population increases gradually as one moves away from the infestation point in association test whereas it decreases in the control. With regards to these results, it appears that O. gratissimum has biocide effects on M. persicae. This plant may be used in an integrated pest management strategy in the production of vegetable to reduce the use of synthetic pesticides and avoid chemicals residues. [less ▲]

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See detailCharacterization and biocontrol properties of Lactuca sativa rhizosphere microbiota in an aquaponic system
Stouvenakers, Gilles ULg; Massart, Sébastien ULg; Jijakli, Haissam ULg

Poster (2016, May 17)

Aquaponics is an integrated recirculated system that combines aquaculture and hydroponic plant production. The dissolved nutrients generated by the fish rearing after bacterial activities are used by the ... [more ▼]

Aquaponics is an integrated recirculated system that combines aquaculture and hydroponic plant production. The dissolved nutrients generated by the fish rearing after bacterial activities are used by the plants for their growth. This uptake reduces the accumulation of some molecules which allow a longer water recirculation. When comparing growth conditions between aquaponics and hydroponics, we observed much lower concentration of several key nutrients in aquaponics. Nevertheless, several experimentations report similar or better yield in aquaponics compared with hydroponics. One explanation of this phenomenon could be linked to microbial actions. Nowadays, microorganisms related to aquaculture and hydroponics are well characterized but very little is known about the microbiota associated with aquaponic system. The first aim of this study is to characterize the rhizosphere microbiota (metagenomics) of lettuces growing in an aquaponics system. A NGS approach targeting the 16S rDNA will be carried out to evaluate the bacterial composition and diversity. The second aim is to assess the resistance of aquaponics lettuces following a pest introduction. Yields, symptoms and microbial changes due to the pest will be recorded and analysed to determine if aquaponics systems provide a better plant protection than hydroponics. Depending on the results, the final steps will be to identify the optimal conditions for the management of the potential beneficial microbiota or isolate a beneficial microorganism. [less ▲]

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See detailLa réception de la littérature médiévale de langue française en Hainaut (XVe-XVIe s.)
Adam, Renaud ULg

Scientific conference (2016, May 17)

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See detailAvatar et jeu vidéo. Réflexions sur le rapport au corps virtuel
Delbouille, Julie ULg

Scientific conference (2016, May 17)

Cette intervention se penche sur les différentes modalités relationnelles qui s’instaurent entre le corps physique du joueur et son répondant virtuel. La question du rapport au corps est centrale dans la ... [more ▼]

Cette intervention se penche sur les différentes modalités relationnelles qui s’instaurent entre le corps physique du joueur et son répondant virtuel. La question du rapport au corps est centrale dans la relation avatariale : touchant à la tension entre l’ « ici » — la physicalité du joueur faisant face à l’écran — et le « là » — la présence de l’avatar au sein de l’univers de jeu —, elle met en relief le paradoxe caractérisant le rôle actif du joueur, dont l’action s’étend à la fois au sein et aux marges du jeu. Cette problématique du rapport au corps, entendu comme « moyen général d’avoir un monde », apporte un regard neuf sur l’histoire du jeu vidéo depuis ses origines. [less ▲]

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See detailNew elicitors to protect wheat against Zymoseptoria tritici: biocontrol tools for IPM strategies
Le Mire, Géraldine ULg; SIAH, Ali; BRISSET, Marie-Noëlle et al

Conference (2016, May 17)

Elicitors are increasingly considered as promising biocontrol tools in the preventive treatment of plants against various diseases. These plant-immunity triggering compounds, also called “stimulators of ... [more ▼]

Elicitors are increasingly considered as promising biocontrol tools in the preventive treatment of plants against various diseases. These plant-immunity triggering compounds, also called “stimulators of plant natural defenses”, induce a general and systemic resistance of the plant to a large spectrum of biotic stresses. Today, focus is made on the crucial protection of wheat, as one of the most cultivated crop plants in the world. This crop is constantly challenged by a persistent and harmful fungus known as Zymoseptoria tritici, responsible of the Septoria Tritici Blotch (STB) disease. Control of this disease mainly depends on phytosanitary products, and the social and economic importance of wheat make it all the more urgent to identify and develop new elicitors as biocontrol tools in wheat IPM strategies. This study focuses on the screening of nine molecules of various origins and structures for their potential eliciting properties to protect winter wheat against Zymoseptoria tritici. Three products were selected after screening trials in greenhouse conditions: EGL1, EGL4, and EGL5. They were efficient to reduce foliar disease symptoms from 40 to 80%. The biocide activity and phytotoxicity of these 3 products were evaluated directly towards the pathogen and the plant under laboratory and greenhouse conditions, respectively. On the other hand, the triggered signaling pathways were investigated by studying the activity of the defense-related enzymes lipoxygenase (LOX), peroxidase (POX) and phenylalanine ammonia-lyase (PAL) in treated wheat leaves. In addition, the expression of five defense genes (lox, pal, pox2, chi, pr1) was studied by qRT-PCR in wheat leaves treated with these elicitors and/or inoculated with Zymoseptoria tritici. The corresponding results will be presented and discussed, with the perspective to investigate the influence of environmental parameters on the elicitation capacity and the efficacy of the elicitors in field conditions. [less ▲]

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