Last 7 days
Bookmark and Share    
Full Text
See detailAharonov-Bohm oscillations of bosonic matter-wave beams in the presence of disorder and interaction
Chrétien, Renaud ULg; Dujardin, Julien; Petitjean, Cyril ULg et al

Poster (2016, May 18)

We study the one-dimensional (1D) transport properties of an ultracold gas of Bose-Einstein condensed atoms through Aharonov-Bohm (AB) rings. Our system consists of a Bose-Einstein condensate (BEC) that ... [more ▼]

We study the one-dimensional (1D) transport properties of an ultracold gas of Bose-Einstein condensed atoms through Aharonov-Bohm (AB) rings. Our system consists of a Bose-Einstein condensate (BEC) that is outcoupled from a magnetic trap into a 1D waveguide which is made of two semi-infinite leads that join a ring geometry exposed to a synthetic magnetic flux φ. We specifically investigate the effects both of a disorder potential and of a small atom-atom contact interaction strength on the AB oscillations. The main numerical tools that we use for this purpose are a mean-field Gross-Pitaevskii (GP) description and the truncated Wigner (tW) method. We find that a correlated disorder suppress the AB oscillations leaving thereby place to weaker amplitude, half period oscillations on transmission, namely the Aronov-Al’tshuler-Spivak (AAS) oscillations. The competition between disorder and interaction leads to a flip of the transmission at the AB flux φ = π. This flip could be a possible preliminary signature of an inversion of the coherent backscattering (CBS) peak. Our study paves the way to an analytical description of the inversion of that peak. [less ▲]

Detailed reference viewed: 26 (4 ULg)
Full Text
Peer Reviewed
See detailAnalyse de l'implantation d'une approche de formation interactive à destination des entraîneurs de football
Theunissen, Catherine ULg; Lombard, Gilles ULg; Cloes, Marc ULg

Conference (2016, May 18)

Les méthodes qui aident à la formation des entraîneurs sont en perpétuelle remise en question. Intéressée par les méthodes interactives diffusées par l’Association Canadienne des Entraîneurs (ACE ... [more ▼]

Les méthodes qui aident à la formation des entraîneurs sont en perpétuelle remise en question. Intéressée par les méthodes interactives diffusées par l’Association Canadienne des Entraîneurs (ACE), l’Association des Clubs Francophones de Football (Belgique) a choisi de tester la mise en place d’une approche similaire au sein de sa formation des cadres. Pour évaluer la pertinence du projet, plusieurs sources de données ont été utilisées : questionnaires pré- et post-formation pour les candidats, interviews et questionnaires de perception de séances pour les formateurs ainsi que des observations de terrain. Les résultats montrent que les formateurs ne semblent pas complètement à l’aise dans leur nouveau rôle de modérateur et délaissent les outils interactifs lorsqu’ils rencontrent un obstacle. De leur côté, les candidats sont séduits par ces nouvelles méthodes et jugent les résultats des travaux de meilleure qualité. Des adaptations concrètes sont proposées pour améliorer le système. [less ▲]

Detailed reference viewed: 18 (0 ULg)
Full Text
See detailEthane rise associated with North American oil and gas exploitation
Franco, Bruno ULg; Mahieu, Emmanuel ULg; Emmons, Louisa et al

Conference (2016, May 18)

Ethane (C2H6) is mainly emitted in the atmosphere from leakage during production and transport of natural gas, biofuel consumption and biomass burning. As it shares concurrent anthropogenic emission ... [more ▼]

Ethane (C2H6) is mainly emitted in the atmosphere from leakage during production and transport of natural gas, biofuel consumption and biomass burning. As it shares concurrent anthropogenic emission sources with methane (CH4), a better understanding of the atmospheric distribution of C2H6 and any trends in its abundance can be used to better constrain the sources of CH4 from oil and gas activities. Until very recently, the C2H6 abundance in the atmosphere has been declining due to the reduction of fugitive emissions as a result of air pollution abatement measures. However, a renewal of the atmospheric C2H6 burden has been detected over North America and Europe from 2009 onwards. It is attributed to the unprecedented growth in the exploitation of shale gas and tight oil reservoirs in North America. Using time series of C2H6 abundance derived from ground-based high-resolution infrared solar absorption spectra recorded at complementary NDACC FTIR sites, we present here sharp C2H6 rises in the Northern Hemisphere, of up to 5 %/yr since 2009. Using model simulations, we show that the HTAP2 bottom-up inventories for anthropogenic emissions greatly underestimate the observed pre-increase C2H6 abundances and that they are too low by a factor two. We also evaluate new top-down emissions of C2H6 from the North American oil and gas activities, biofuel consumption and biomass burning, derived from space-borne observations of CH4 from GOSAT. We find a good agreement with the observations at the North American mid-latitudinal sites, close to regions with high drilling productivity, but an overestimation at remote sites. We also estimate that the North American C2H6 emissions have increased by 75% over the past six years (2009-2014), annihilating the benefits of more than two decades of successful anthropogenic emission reduction, and that the associated annual CH4 emissions from the North American oil and gas sector grew from 20 to 35 Tg/yr over the same period. [less ▲]

Detailed reference viewed: 34 (5 ULg)
Full Text
Peer Reviewed
See detailExtracellular vesicles in blood, milk and body fluids of the female and male urogenital tract and with special regard to reproduction
Foster, Brandon; Balassa, Timea; Benen, Thomas et al

in Critical Reviews in Clinical Laboratory Sciences (2016)

Detailed reference viewed: 39 (2 ULg)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 8 (1 ULg)
Full Text
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 ▲]

Detailed reference viewed: 17 (0 ULg)
Full Text
Peer Reviewed
See detailDébats autour du concept de type en typologie des langues
Lttr13; Badir, Sémir ULg; Polis, Stéphane ULg et al

Conference (2016, May 18)

Detailed reference viewed: 20 (3 ULg)
Full Text
See detailL'ordinateur dans la littérature allemande au tournant du millénaire
Dupont, Bruno ULg

Poster (2016, May 18)

Detailed reference viewed: 10 (0 ULg)
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 ▲]

Detailed reference viewed: 24 (1 ULg)
See detailGérer l’Etat belge, pas la S.A. Belgique
Delvenne, Pierre ULg; Rossignol, Nicolas ULg

Article for general public (2016)

Detailed reference viewed: 11 (0 ULg)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 25 (4 ULg)
Full Text
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 ▲]

Detailed reference viewed: 14 (1 ULg)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 28 (8 ULg)
Full Text
Peer Reviewed
See detailAnticoherence of spin states with point-group symmetries
Baguette, Dorian ULg; Damanet, François ULg; Giraud, Olivier et al

Poster (2016, May 18)

Detailed reference viewed: 25 (4 ULg)
Full Text
Peer Reviewed
See detailSuper- and subradiance from indistinguishable atoms with quantized motion
Damanet, François ULg; Braun, Daniel; Martin, John ULg

Poster (2016, May 18)

Detailed reference viewed: 20 (2 ULg)
Full Text
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 ▲]

Detailed reference viewed: 13 (2 ULg)
Full Text
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 ▲]

Detailed reference viewed: 54 (3 ULg)