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See detailAllelopathic potential of sunflower against the great brome
Bouhaouel, Imen ULg; Gfeller, Aurélie; Fauconnier, Marie-Laure ULg et al

Poster (2014, February 06)

Control methods commonly used to suppress the great brome (Bromus diandrus Roth., syn. Bromus rigidus Roth. subsp. gussonii Parl.) in Tunisian cereal crop are essentially chemical, raising both efficacy ... [more ▼]

Control methods commonly used to suppress the great brome (Bromus diandrus Roth., syn. Bromus rigidus Roth. subsp. gussonii Parl.) in Tunisian cereal crop are essentially chemical, raising both efficacy and safety issues. The introduction of allelopathic species into the crop rotation or utilizing allelopathic plants as living/green mulches has been suggested as a cost-effective way to reduce the weed presence. Among these species, the sunflower (Helianthus annuus L.) has shown an allelopathic potential against some troublesome weed species. In this study, we analyzed the biological activities of water extract of different tissues (root, shoot, leaf and flower) of sunflower on the seedling establishment of the great brome. In a second experiment, the allelopathic influence of sunflower residues (leaf or flower) against this weed was also studied under glasshouse conditions at more advanced stages of growth using different concentrations (0, 6, 12 and 18g tissue dry weight / kg of soil). The first experiment showed an effect depending on the parts of the sunflower. Indeed, the roots seem to be the less allelopathic part (22% of root inhibition growth) as compared to the leaves and flowers (82% and 100%, respectively). This potential seems to simultaneously affect the radicle and the coleoptile growth of the great brome. In the second experiment, weed growth was inhibited in a dose-dependent manner, using increasing amounts of sunflower residues. The allelopathic potential of the leaves or flowers reduced both the root or shoot length and biomass accumulation of the weed. These results suggest that the sunflower can be a good previous crop for cereal cultivation by controlling the presence of some weeds, including the great brome. In this perspective, the inhibitory effects of sunflower residues on cultivated cereals in the field need to be assessed. [less ▲]

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See detailImpact of extraction procedures on the chemical, rheological and textural properties of ulvan from Ulva lactuca of Tunisia coast
Yaich, Hela; Garna, Haikel; Besbes, Souhail et al

in Food Hydrocolloids (2014), (40), 53-63

The impact of the extraction conditions has been studied on the yield, chemical composition, rheological and textural properties of ulvan from the green seaweed Ulva lactuca. High ulvan yield was obtained ... [more ▼]

The impact of the extraction conditions has been studied on the yield, chemical composition, rheological and textural properties of ulvan from the green seaweed Ulva lactuca. High ulvan yield was obtained after combining enzymatic and chemical extraction but the lowest yield results at the drastic conditions (pH 1.5 and 90 C). Besides, solvent acidity was an important parameter controlling the ulvan extraction efficiency. The different extraction processes affected chemical composition of ulvan extracts and in particular, sulphate, ash and sugar contents. Low proportions of galactose, glucose and protein were also found in sulphated polysaccharides. The extract, which is resulted from combined enzymatic and chemical extraction, was mainly composed of high peak molecular weight polysaccharides. Ulvan hy-drocolloids demonstrated a pseudoplastic behavior. Viscoelastic behavior was carried out at a concen-tration of 1.6% (w/v) in the presence of 7 mM sodium tetraborate and at pH 7.5. However, polysaccharides formed a gel. It was not the case for the extract at pH 1.5 and 90 C under the same conditions. The results showed that a significant effect of the conditions of extraction on the textural characteristic (firmness, springiness and adhesiveness) of ulvan gels. [less ▲]

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See detailExperimental investigation of meandering jets in shallow reservoirs
Peltier, Yann ULg; Erpicum, Sébastien ULg; Archambeau, Pierre ULg et al

in Environmental Fluid Mechanics (2014)

Meandering flows in rectangular shallow reservoirs were experimentally investi- gated. The characteristic frequency, the longitudinal wave length and the mean lateral exten- sion of the meandering jet ... [more ▼]

Meandering flows in rectangular shallow reservoirs were experimentally investi- gated. The characteristic frequency, the longitudinal wave length and the mean lateral exten- sion of the meandering jet were extracted from the first paired modes, obtained by a proper orthogonal decomposition of the surface velocity field measured by large scale PIV. The depth-normalised characteristic lengths and the Strouhal number were then compared to the main dimensionless numbers characterizing the experiments: Froude number, friction num- ber and reservoir shape factor. The normalised wave length and mean lateral extension of the meandering jet are neither correlated with the Froude number nor with the reservoir shape factor; but a clear relationship is found with the friction number. Similarly, the Strouhal num- ber is found proportional to a negative power of the friction number. In contrast, the Froude number and the reservoir shape factor enable to predict the occurrence of a meandering flow pattern: meandering jets occur for Froude number greater than 0.21 and for a shape factor smaller than 6.2. [less ▲]

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See detailForecasting Daily Solar Energy Production Using Robust Regression Techniques
Louppe, Gilles ULg; Prettenhofer, Peter

Conference (2014, February 05)

We describe a novel approach to forecast daily solar energy production based on the output of a numerical weather prediction (NWP) model using non-parametric robust regression techniques. Our approach ... [more ▼]

We describe a novel approach to forecast daily solar energy production based on the output of a numerical weather prediction (NWP) model using non-parametric robust regression techniques. Our approach comprises two steps: First, we use a non-linear interpolation technique, Gaussian Process regression (also known as Kriging in Geostatistics), to interpolate the coarse NWP grid to the location of the solar energy production facilities. Second, we use Gradient Boosted Regression Trees, a non-parametric regression technique, to predict the daily solar energy output based on the interpolated NWP model and additional spatio-temporal features. Experimental evidence suggests that two aspects of our approach are crucial for its effectiveness: a) the ability of Gaussian Process regression to incorporate both input and output uncertainty which we leverage by deriving input uncertainty from an ensemble of 11 NWP models and including convidence intervals alongside the interpolated point estimates and b) the ability of Gradient Boosted Regression Trees to handle outliers in the outputs by using robust loss functions - a property that is very important due to the volatile nature of solar energy output. We evaluated the approach on a dataset of daily solar energy measurements from 98 stations in Oklahoma. The results show a relative improvement of 17.17% and 46.19% over the baselines, Spline Interpolation and Gaussian Mixture Models, resp. [less ▲]

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See detailIs dark matter made of mirror matter? Evidence from cosmological data
Ciarcelluti, Paolo; Wallemacq, Quentin ULg

in Physics Letters B (2014), 729

We present new fast numerical simulations of cosmic microwave background and large scale structure in the case in which the cosmological dark matter is made entirely or partly of mirror matter. We ... [more ▼]

We present new fast numerical simulations of cosmic microwave background and large scale structure in the case in which the cosmological dark matter is made entirely or partly of mirror matter. We consider scalar adiabatic primordial perturbations at linear scales in a flat Universe. The speed of the simulations allows us for the first time to use Markov Chain Monte Carlo analyses to constrain the mirror parameters. A Universe with pure mirror matter can fit very well the observations, equivalently to the case of an admixture with cold dark matter. In both cases, the analyses show a clear indication of the presence of a consistent amount of mirror dark matter, 0.05 < Ω_{mirror} h^2 < 0.12. [less ▲]

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See detailStation de pompage de Jemeppe-sur-Meuse : suivi de forages et rapport de synthèse
Delvoie, Simon ULg; Collin, Frédéric ULg

Report (2014)

Suivi et analyse de neuf forages carottés réalisés à Jemeppe-sur-Meuse au sein de roches houillères. Les forages atteignent des cotes entre +35,00 et +31,00 m.

Detailed reference viewed: 9 (3 ULg)
See detailHors-cadres : des images qui manquent. Quand le documentaire ne peut pas tout montrer.
Hamers, Jérémy ULg

Conference given outside the academic context (2014)

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See detailTransnational modelling of the Meuse District with PegOpera simulation software
Grard, Aline ULg; Everbecq, Etienne ULg; MAGERMANS, POL ULg et al

in International Journal of River Basin Management (2014)

The environmental software PEGOPERA is a new tool resulting from the coupling of the PEGASE model (Planification Et Gestion de l’ASsainissement des Eaux, French acronym for planning and management of ... [more ▼]

The environmental software PEGOPERA is a new tool resulting from the coupling of the PEGASE model (Planification Et Gestion de l’ASsainissement des Eaux, French acronym for planning and management of water purification) with a friendly Graphical User Interface. PEGASE is an integrated and physically based river/basin model and is devoted to the characterisation of the physico-chemical state of surface water, at the scale of a whole watershed or basin, including International River Basin District (IRBD). The aim of the model is to simulate non stationary scenarios at various scales (from a few km² to hundreds of thousands km²) while handling the entire river tree (hundreds to thousands of water bodies). The purpose of PEGOPERA is to provide the stakeholders - as regards to surface water management - with a tool dedicated to the deterministic calculation of water quality of the rivers taking into account pollutant loads and discharges. In the context of the Water Framework Directive 2000/60/EC, the international coordination between neighbouring states and regions is required. The PEGOPERA software is adapted to simulate the IRBD Meuse. Indeed: i. An integrated transnational database relevant to the entire district is available; ii. The software is operational: the Meuse application has been calibrated and validated independently on most of regional sub-basins of the district; iii. The software could be used to simulate historical and future scenarios to assess water quality improvement that may be expected after applying basic and supplementary measures. The results demonstrate the relevance of the use of this software in this kind of transnational modelling. Some regions of the International District of the Meuse are validated on historical situations. Other parts still need to be improved in terms of consolidating the input databases. Prospective scenarios implementing measures from the WFD are carried out at this District scale. [less ▲]

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See detailLe rêve: la voie royale de la découverte freudienne de l'inconscient
Naziri, Despina ULg

Diverse speeche and writing (2014)

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See detailOpinions, attitudes et comportements politiques. Tome 1. Notes provisoires
Grandjean, Geoffrey ULg

Learning material (2014)

Detailed reference viewed: 25 (5 ULg)
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See detailCoastal flood damage and adaptation costs under 21st century sea-level rise
Hinkel, J.; Lincke, D.; Vafeidis, A. T. et al

in Proceedings of the National Academy of Sciences of the United States of America (2014), online

Coastal flood damage and adaptation costs under 21st century sea-level rise are assessed on a global scale taking into account a wide range of uncertainties in continental topography data, population data ... [more ▼]

Coastal flood damage and adaptation costs under 21st century sea-level rise are assessed on a global scale taking into account a wide range of uncertainties in continental topography data, population data, protection strategies, socioeconomic development and sea-level rise. Uncertainty in global mean and regional sea level was derived from four different climate models from the Coupled Model Intercomparison Project Phase 5, each combined with three land-ice scenarios based on the published range of contributions from ice sheets and glaciers. Without adaptation, 0.2–4.6% of global population is expected to be flooded annually in 2100 under 25–123 cm of global mean sea-level rise, with expected annual losses of 0.3–9.3% of global gross domestic product. Damages of this magnitude are very unlikely to be tolerated by society and adaptation will be widespread. The global costs of protecting the coast with dikes are significant with annual investment and maintenance costs of US$ 12–71 billion in 2100, but much smaller than the global cost of avoided damages even without accounting for indirect costs of damage to regional production supply. Flood damages by the end of this century are much more sensitive to the applied protection strategy than to variations in climate and socioeconomic scenarios as well as in physical data sources (topography and climate model). Our results emphasize the central role of long-term coastal adaptation strategies. These should also take into account that protecting large parts of the developed coast increases the risk of catastrophic consequences in the case of defense failure. [less ▲]

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See detailQuand le manuscrit devient tablette : préservation et exploitation d’un patrimoine culturel et universitaire à l’ère numérique
Simon, Stéphanie ULg

Conference given outside the academic context (2014)

Au cours de l'année 2013, le Réseau des Bibliothèques de l'ULg a pu réaliser la numérisation d'une cinquantaine de manuscrits exceptionnels issus de ses collections. Cette présentation replace ce projet ... [more ▼]

Au cours de l'année 2013, le Réseau des Bibliothèques de l'ULg a pu réaliser la numérisation d'une cinquantaine de manuscrits exceptionnels issus de ses collections. Cette présentation replace ce projet dans le cadre général de la numérisation du patrimoine et vous en détaille les différentes étapes. [less ▲]

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See detailPaleoenvironmental record of the Amik Basin (Amuq Plain, Southern Turkey) over the last 4000 years
Hubert, Aurelia ULg; El Ouahabi, Meriam ULg; Lebeau, Hélène ULg et al

Poster (2014, February 04)

Continous human occupation is attested in the Amik Basin since 6000-7000 BC. The low-lying Amuq plain is covered by tell settlements first explored by Robert Braidwood in the 1930s. The Basin also is ... [more ▼]

Continous human occupation is attested in the Amik Basin since 6000-7000 BC. The low-lying Amuq plain is covered by tell settlements first explored by Robert Braidwood in the 1930s. The Basin also is crossed by The Dead Sea Fault (DSF), a major neotectonic structure in the Middle East extending from the Red Sea in the south to Turkey in the north. The study focuses on the sedimentary record of the Amik Lake occupying the central part of the Basin. Our objective is to constrain major paleo-environmental changes in the area over the last 4000 years and assess possible human impact. The lake has been drained and progressively dried up since the mid-50s so that it is not watered during the summer season and constitutes a unique opportunity to collect sediment records. Sediments were collected at 1 cm to 2 cm intervals in a trench and in cores up to a depth of 5 meters in the clay deposits. A diverse array of complementary methods is applied to study the records: magnetic susceptibility, grain size, organic matter and inorganic carbon (L.O.I), XRD mineralogy, XRF geochemistry, carbon geochemistry. The age of the record is constrained combining radionuclide and radiocarbon dating. The record shows two intense phases of soil erosion with enrichments in Chromium and Nickel. The most recent erosion phase might be linked with enhanced development during the Roman and the growth of the Antioch City. The oldest one would occur around 3000 BC. The record also allows reconstructing past lake level variations and discusses the results in comparison with variations of the Dead Sea. [less ▲]

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See detailLes représentations de Synagoga aux portails occidentaux de la cathédrale d’Amiens : l’illustration de l’ « antijudaïsme » au lendemain de Latran IV ?
Lekane, Marie ULg

Conference (2014, February 04)

Les portails occidentaux amiénois sont munis de trois représentations de la Synagogue, sous la forme bien connue d’une personnification féminine aux yeux bandés. Deux scènes particulières, montrant la ... [more ▼]

Les portails occidentaux amiénois sont munis de trois représentations de la Synagogue, sous la forme bien connue d’une personnification féminine aux yeux bandés. Deux scènes particulières, montrant la Synagoga, se jouent sur des culots du portail de la Vierge, sous les pieds des Rois mages. Si l’une de ces scènes semble représenter le découronnement de la figure allégorique par le Christ, la seconde est plus énigmatique. Au portail du Jugement dernier, sous les pieds de l’archange Michel, se loge le couple antagoniste Ecclesia-Synagoga. La position éminemment négative de la Synagogue – sous le plateau démoniaque, à senestre du Christ, côtoyant le monde infernal – fait-elle écho aux récentes positions contre les Juifs prises et actées lors du Concile de Latran IV (1215) ? Afin de pouvoir amener des pistes de réflexions sur ces points, déjà soulevés par certains auteurs (W. Schlink, 1991), nous interrogerons les sources historiques sur la présence effective d’une communauté juive à Amiens et sur leurs conditions de vie. En outre, et plus généralement, nous analyserons les retombées tangibles des décisions prises lors du Concile de 1215, auquel participait Jean d’Abbeville, doyen de la cathédrale d’Amiens au moment de sa reconstruction, volontiers présenté comme « programmateur » de l’ensemble. Il est indispensable de reconsidérer soigneusement ces images et leurs composantes afin de définir leurs particularités et d’infirmer ou confirmer un « antijudaïsme » aux portails amiénois, ou du moins de pouvoir le caractériser. [less ▲]

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See detailMariage pour tous, homoparentalité
Naziri, Despina ULg

Conference given outside the academic context (2014)

Detailed reference viewed: 12 (0 ULg)
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See detailHigh-frequency A-type pulsators discovered using SuperWASP
Holdsworth, Daniel L.; Smalley, B.; Gillon, Michaël ULg et al

in Monthly Notices of the Royal Astronomical Society (2014)

We present the results of a survey using the WASP archive to search for high-frequency pulsations in F-, A- and B-type stars. Over 1.5 million targets have been searched for pulsations with amplitudes ... [more ▼]

We present the results of a survey using the WASP archive to search for high-frequency pulsations in F-, A- and B-type stars. Over 1.5 million targets have been searched for pulsations with amplitudes greater than 0.5 millimagnitude. We identify over 350 stars which pulsate with periods less than 30 min. Spectroscopic follow-up of selected targets has enabled us to confirm 10 new rapidly oscillating Ap stars, 13 pulsating Am stars and the fastest known δ Scuti star. We also observe stars which show pulsations in both the high-frequency domain and the low-frequency δ Scuti range. This work shows the power of the WASP photometric survey to find variable stars with amplitudes well below the nominal photometric precision per observation. [less ▲]

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