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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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See detailDevelopment of a semiochemical-based control method against the walnut husk fly
Sarles, Landry ULg; Heuskin, Stéphanie ULg; Verheaghe, Agnès et al

Conference (2016, May 17)

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See detailHerbicidal activity of Tunisian plant extracts against various weeds
Ben Kaab, Sofiène ULg; Parisi, Olivier ULg; Ksouri, Riadh et al

Conference (2016, May 17)

In agricultural systems, weeds can dramatically reduce crop yields (by the constant competition for water and nutrients) and interfere with plant functions to suppress their growth causing huge economic ... [more ▼]

In agricultural systems, weeds can dramatically reduce crop yields (by the constant competition for water and nutrients) and interfere with plant functions to suppress their growth causing huge economic losses.Yield losses can reach up to 34% in crops. Plant extracts are known since a long time to have phytotoxicity potentialities and could be used as new natural compounds with bioherbicide activities. The study began with the selection of ten plant species suspected to be phytotoxic due to their wealth of phenolic, terpene and alcaloid compounds, such as flavonoids and phenolic acids coumarins. Then, three weeds were selected from Maghreb and European weeds as models (Phalaris minor, Sylibum marianum and Trifolium incanatum). Aerial plant materials were grounded and macerated with methanol for 24H. Methanol was then eliminated along rotavapor. The yield of plant extract varied between 5.29% and 29.71 % following the species. The essential oil was extracted by hydrodistillation using a Clevenger type apparatus (with a yield of 1.2%). Methanol extracts and the essential oil were then tested for their herbicidal activity in post-emergence assays against the three weeds species.The most active extracts were selected and formulated to increase their efficiency. Post-emergence bioassays consisted in spraying each extract at 3 concentrations (7500, 20000 and 340000 ppm) at 2 leaves stage . Pelargonic acid was used as commercial positive control at 34000 ppm. After 7 days on incubation in greenhouses, results showed that E6, presented poor phytotoxicity against three weeds at 7500 and 20000 ppm. However, E6 caused total wilting and several leaf blight against Phalaris minor and Trifolium incanatum and sever necrosis against Sylibum marianum. At that higher concentration of 34000 ppm. , the extracts E3 and E8 and the essential oil appeared also phytotoxic. The three extracts and the essential oil were selected for the formulation. After formulation to enhance the distribution, the coverage and the penetration of the active molecules at 34000 ppm, E3, E6, E8 and essential oil presented a high herbicidal activity compared with the extracts without formulation. E6 with the formulation has completely punctured Trifolium incanatum and suppressed growth of Phalaris minor and Sylibum marianum. The results of this study reveal that plant extracts, after formulation, are more effective in inhibiting weed growth. The strong weed suppressive ability of formulated E6 therefore offers interesting possibilities as an effective natural environment-friendly approach for weed management. [less ▲]

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See detailInsights gained from metagenomic sequencing of apple fruit surface (cv. Pinova)
Angeli, Dario; Massart, Sébastien ULg; Sare, Abdoul Razack ULg et al

Poster (2016, May 17)

Plant microbial communities (microbiota) living at the surface of fruit have been the source of the majority of biocontrol agents (BCAs). Despite this interest, their role as a community has been poorly ... [more ▼]

Plant microbial communities (microbiota) living at the surface of fruit have been the source of the majority of biocontrol agents (BCAs). Despite this interest, their role as a community has been poorly studied so far. They holistic study was an unattainable objective due to the absence of techniques to survey microbial communities and their evolution. The recent developments in high-throughput sequencing (HTS) have now enabled the holistic analysis of the microbiota genomes. A pioneering assay has been carried out to get insight into the microbiota of apple surface through metagenome sequencing. Apple from Pinova cultivar have been sampled in orchard and the microbiota isolated. After DNA extraction, the HTS assay generated 14.5 Gbases which were assembled in 133,888 contigs. These contigs provided useful information on taxonomic composition of the microbiota. A total of 1398 bacterial species and 397 fungal species have been identified. Among them, 22 species corresponded to known apple pathogens (Penicillium expansum, Penicillium spp, Botrytis cinerea, Monilinia fructicola, Nectria haematococca, Glomerella cingulate, G. graminicola, Alternaria alternate, Alternaria brassicicola, A. citri, A. longipes, A. solani, A. tenuissima, Fusarium solani, F. oxysporum, F. culmorum, F. lateritium, Mucor circinelloides, M. hiemalis, F. racemosus, Venturia inaequalis, Cladosporium cladosporioides). In addition, several contigs were assigned to species or genus of known BCA strains like Pichia canadensis, Bacillus sp., Debaryomyces hansenii, Aureobasidium pullulans and Pantoea vagans. These results will be discussed. In any case, these results underline a very diverse microbial community whose role needs to be characterized. In this line, the functional analysis (gene function determination) of the contigs is ongoing. [less ▲]

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See detailInfluence of the balls kinematics and ball/race contact models on quasi-static approaches for ball bearing
Servais, Christophe ULg; Bozet, Jean-Luc ULg

Conference (2016, May 17)

The frictional power dissipated within dry lubricated ball bearings is a prime concern, especially for high speed applications. Nevertheless, the exact balls behavior is still a source of interrogations ... [more ▼]

The frictional power dissipated within dry lubricated ball bearings is a prime concern, especially for high speed applications. Nevertheless, the exact balls behavior is still a source of interrogations. Firstly, a comparison of several ball/race contact models has been performed by prescribing the kinematical variables. This has been done by using an existing quasi-static approach to reach the ball bearing equilibrium. Secondly, a parametric study has been carried out on the ball kinematics. This time the contact model remained fixed. The results demonstrate the predominance of the kinematics on the ball bearing behavior with an emphasis on the dissipated power within ball/race contacts. This shows that the kinematics must be rightly computed. On the other hand, the ball/race contact model doesn’t necessitate a high refinement in order to evaluate the ball bearing equilibrium. Conversely, this refinement is essential for a precise evaluation of the power losses. [less ▲]

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See detailMonstres et images : premiers pas vers une redéfinition de la monstruosité cinématographique
Jousten, Lison ULg

Conference (2016, May 17)

La communication propose un déplacement du monstre en tant qu’objet filmé pour l’envisager en tant que forme filmique. Cette hypothèse est avancée puis expérimentée par le biais d'une étude de cas.

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See detailFUNCTIONAL SPECIFICATION METHODOLOGY FOR AN ARCHITECTURAL MODELER SUPPORTING A MODULAR CONSTRUCTIVE SYSTEM
Boulanger, Christelle ULg; Rahhal, Anabelle ULg; Delfosse, Vincent ULg et al

in Design2016 (2016, May 16)

This article presents a methodological approach which helped the software development of an architectural modeler that aims to support the life cycle of buildings with a modular construction system. The ... [more ▼]

This article presents a methodological approach which helped the software development of an architectural modeler that aims to support the life cycle of buildings with a modular construction system. The modeler assists the building composition processes, the production of useful documents like drawing plans, quantities and specifications, and the evaluation of the thermal performance of the building at any phase of its design. Conducted within a multidisciplinary team of architects engineers, computer engineers and ergonomists, this methodology is based on a constant interaction between the various skills, so that the different perspectives are systematically integrated into the decision process. The methodology is based on the analysis of three fields of functions (composition - production and evaluation) which are considered simultaneously through a theoretical framework stemming from ergonomics: Activity Theory [Engeström 1987]. At first, the software development context is presented. Then, the choice of the Activity Theory as a framework for the analysis will be motivated. The next section relates the multiple concepts of the methodology to each others, in order to identify the principles as well as the inputs and the outputs. Each step in its implementation is then described, followed by the results in terms of the software interface. Finally, the discussion that will follow will consider the contributions and limitations of this methodological approach in the understanding of a system, in order to offer an efficient IT support. [less ▲]

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See detailEmbargo on Lion Hunting Trophies from West Africa: An Effective Measure or a Threat to Lion Conservation ?
Bouché, Philippe; Crosmary, William; Kafando, Pierre et al

in PLoS ONE (2016), 11(5), 0155763

The W-Arly-Pendjari (WAP) ecosystem, shared among Benin, Burkina Faso and Niger, represents the last lion stronghold of West Africa. To assess the impact of trophy hunting on lion populations in hunting ... [more ▼]

The W-Arly-Pendjari (WAP) ecosystem, shared among Benin, Burkina Faso and Niger, represents the last lion stronghold of West Africa. To assess the impact of trophy hunting on lion populations in hunting areas of the WAP, we analyzed trends in harvest rates from 1999 to 2014. We also investigated whether the hunting areas with higher initial hunting intensity experienced steeper declines in lion harvest between 1999 and 2014, and whether lion densities in hunting areas were lower than in national parks. Lion harvest rate remained overall constant in the WAP. At initial hunting intensities below 1.5 lions/1000km2, most hunting areas experienced an increase in lion harvest rate, although that increase was of lower magnitude for hunting areas with higher initial hunting intensity. The proportion of hunting areas that experienced a decline in lion harvest rate increased at initial hunting intensities above 1.5 lions/1000km2. In 2014, the lion population of the WAP was estimated with a spoor count at 418 (230–648) adults and sub-adult individuals, comparable to the 311 (123–498) individuals estimated in the previous 2012 spoor survey. We found no significant lion spoor density differences between national parks and hunting areas. Hunting areas with higher mean harvest rates did not have lower lion densities. The ratio of large adult males, females and sub-adults was similar between the national parks and the hunting areas. These results suggested that the lion population was not significantly affected by hunting in the WAP. We concluded that a quota of 1 lion/1000km2 would be sustainable for the WAP. Based on our results, an import embargo on lion trophies from the WAP would not be justified. It could ruin the incentive of local actors to conserve lions in hunting areas, and lead to a drastic reduction of lion range in West Africa. [less ▲]

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