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See detailComics and Utopia
Dony, Christophe ULg

Scientific conference (2016, April 22)

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See detailNumérisation : quel intérêt pour la recherche ? Quel impact sur la conservation ? Le projet DONum
Simon, Stéphanie ULg

Conference given outside the academic context (2016)

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Peer Reviewed
See detailHeart failure assessment with a multiscale model
Negroni, Jorge; Cabrera-Fischer, Edmundo; Kosta, Sarah ULg et al

Poster (2016, April 21)

Many cardiac diseases lead to heart failure (HF) causing increasing morbidity and mortality worldwide. Several alterations at the myocyte level have been identified, but their specific influence on ... [more ▼]

Many cardiac diseases lead to heart failure (HF) causing increasing morbidity and mortality worldwide. Several alterations at the myocyte level have been identified, but their specific influence on contractile and hemodynamic impairment is not yet clear. Mathematical modeling is a tool to address this issue enabling the analysis of individual myocyte changes on the overall circulatory response. Some myocyte models have been able to reproduce the impact of HF on experimentally detected myocyte components (1), but their integration into a ventricular model forming part of a multiscale circulatory approach has not been fully undertaken. Thus, the aim of this study is to compare the experimental hemodynamic and regional contractile response to acute HF versus a multiscale model based on a human myocyte representation. The experimentally-validated multiscale model shows adequate coupling between myocyte-derived left ventricular chamber and circulatory properties , and would be useful to predict the contractile and hemodynamic response to HF changes in myocyte variables. [less ▲]

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See detailElephant Man. Du cas clinique au monstre cinématographique
Jousten, Lison ULg

Conference given outside the academic context (2016)

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See detailHigh-resolution climate and land surface interactions modeling over Belgium: current state and decennial scale projections
Jacquemin, Ingrid ULg; Henrot, Alexandra-Jane ULg; Beckers, Veronique et al

Poster (2016, April 21)

The interactions between land surface and climate are complex. Climate changes can affect ecosystem structure and functions, by altering photosynthesis and productivity or inducing thermal and hydric ... [more ▼]

The interactions between land surface and climate are complex. Climate changes can affect ecosystem structure and functions, by altering photosynthesis and productivity or inducing thermal and hydric stresses on plant species. These changes then impact socio-economic systems, through e.g., lower farming or forestry incomes. Ultimately, it can lead to permanent changes in land use structure, especially when associated with other non-climatic factors, such as urbanization pressure. These interactions and changes have feedbacks on the climate systems, in terms of changing: (1) surface properties (albedo, roughness, evapotranspiration, etc.) and (2) greenhouse gas emissions (mainly CO2, CH4, N2O). In the framework of the MASC project (« Modelling and Assessing Surface Change impacts on Belgian and Western European climate »), we aim at improving regional climate model projections at the decennial scale over Belgium and Western Europe by combining high-resolution models of climate, land surface dynamics and socio-economic processes. The land surface dynamics (LSD) module is composed of a dynamic vegetation model (CARAIB) calculating the productivity and growth of natural and managed vegetation, and an agent-based model (CRAFTY), determining the shifts in land use and land cover. This up-scaled LSD module is made consistent with the surface scheme of the regional climate model (RCM: ALARO) to allow simulations of the RCM with a fully dynamic land surface for the recent past and the period 2000-2030. In this contribution, we analyze the results of the first simulations performed with the CARAIB dynamic vegetation model over Belgium at a resolution of 1km. This analysis is performed at the species level, using a set of 17 species for natural vegetation (trees and grasses) and 10 crops, especially designed to represent the Belgian vegetation. The CARAIB model is forced with surface atmospheric variables derived from the monthly global CRU climatology or ALARO outputs (from a 4 km resolution simulation) for the recent past and the decennial projections. Evidently, these simulations lead to a first analysis of the impact of climate change on carbon stocks (e.g., biomass, soil carbon) and fluxes (e.g., gross and net primary productivities (GPP and NPP) and net ecosystem production (NEP)). The surface scheme is based on two land use/land cover databases, ECOPLAN for the Flemish region and, for the Walloon region, the COS-Wallonia database and the Belgian agricultural statistics for agricultural land. Land use and land cover are fixed through time (reference year: 2007) in these simulations, but a first attempt of coupling between CARAIB and CRAFTY will be made to establish dynamic land use change scenarios for the next decades. A simulation with variable land use would allow an analysis of land use change impacts not only on crop yields and the land carbon budget, but also on climate relevant parameters, such as surface albedo, roughness length and evapotranspiration towards a coupling with the RCM. [less ▲]

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See detailSupporting integrated and systemic management of windthrow crises by public decision-makers
Riguelle, Simon ULg; Hebert, Jacques ULg; Lejeune, Philippe ULg et al

Poster (2016, April 21)

This poster presents the development of an integrated framework for systemic management of storm damage risk in Wallonia (Belgium) and how it can be implemented throughout the risk management cycle with ... [more ▼]

This poster presents the development of an integrated framework for systemic management of storm damage risk in Wallonia (Belgium) and how it can be implemented throughout the risk management cycle with user-friendly tools and suitable methodologies. [less ▲]

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See detailOccurrence, fate and risk assessment of personal care products in river-groundwater interface
Jurado Elices, Anna ULg; Serra-Roig, M. Pau; Diaz-Cruz, M. Silvia et al

Conference (2016, April 21)

This work presents the occurrence and fate of selected personal care products (PCPs) in the urban river-groundwater interface. To this end, urban groundwater and river samples were collected in Sant Adrià ... [more ▼]

This work presents the occurrence and fate of selected personal care products (PCPs) in the urban river-groundwater interface. To this end, urban groundwater and river samples were collected in Sant Adrià del Besòs (NE of Spain) and a total of 16 PCPs were analyzed including benzophenone derivatives, camphor derivatives, p-aminobenzoic acid derivatives, triazoles and parabens in three different campaigns (from May 2010 to July 2014). These compounds reach the aquifer through the recharge of River Besòs that receives large amounts of effluents from waste water treatment plants. Results shown that most of compounds were not or barely detected (maximum concentrations around 30 ng/L) in groundwater samples during the different sampling campaigns. Only two triazoles, named as benzotriazole (BZT) and methyl benzotriazol (MeBZT) were found at high concentrations in groundwater samples (maximum concentration around 2000 ng/L). The fate of PCPs in the aquifer was assessed using mixing analysis considering the temporal variability of the River Besòs. Overall, measured groundwater concentrations were significantly much lower than those estimated by the mixing of the river water. This observation suggested that most of the PCPs are naturally removed when river water infiltrates the aquifer. However, some compounds were more persistent in the aquifer. These compounds were in descending order: the triazoles MeBZT and BZT followed by the camphor derivative 4MBC. The measured concentrations allowed us to assess the environmental risk posed by the selected UV-Fs (e.g. benzophenone derivatives) in the river-groundwater samples. Hazard Quotients (HQs) for diferent aquatic species were calculated in order to characterise the ecotoxicity potential of the studied compounds in the river-groundwater interface. HQ values will be presented and discussed in the presentation. [less ▲]

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See detailDevelopment of the interfacial air layer in the non-aerated region of high-velocity spillway flows. Instabilities growth, entrapped air and influence on the self-aeration onset
Valero Huerta, Daniel ULg; Bung, Daniel B

in International Journal of Multiphase Flow (2016), 84

Self-aeration is traditionally explained by the water turbulent boundary layer outer edge intersection with the free surface. This paper presents a discussion on the commonly accepted hypothesis behind ... [more ▼]

Self-aeration is traditionally explained by the water turbulent boundary layer outer edge intersection with the free surface. This paper presents a discussion on the commonly accepted hypothesis behind the computation of the critical point of self-aeration in spillway flows and a new formulation is proposed based on the existence of a developing air flow over the free surface. Upstream of the inception point of self-aeration, some surface roughening has been often reported in previous studies which consequently implies some entrapped air transport and air–water flows coupling. Such air flow is proven in this study by presenting measured air velocities and computing the air boundary layer thickness for a 1V:2H smooth chute flow. Additionally, the growth rate of free surface waves has been analysed by means of Ultrasonic Sensors measurements, obtaining also the entrapped air concentration. High-speed camera imaging has been used for qualitative study of the flow perturbations. [less ▲]

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See detailAssessing heat tracing experiment data sets for direct forecast of temperature evolution in subsurface models: an example of well and geophysical monitoring data
Hermans, Thomas ULg; Klepikova, Maria; Caers, Jef

Conference (2016, April 21)

Hydrogeological inverse modeling is used for integrating data and calibrating subsurface model parameters. On one hand, deterministic approaches are relatively fast but fail to catch the uncertainty ... [more ▼]

Hydrogeological inverse modeling is used for integrating data and calibrating subsurface model parameters. On one hand, deterministic approaches are relatively fast but fail to catch the uncertainty related to the spatial distribution of model parameters. On the other hand, stochastic inverse modeling is time-consuming and sampling the full high-dimensional parameter space is generally impossible. Even then, the end result is not the inverted model itself, but the forecast built from such models. In this study, we investigate a prediction-focused approach (PFA) in order to derive a direct statistical relationship between data and forecast without explicitly calibrating any models to the data. To derive this relationship, we first sample a limited number of models from the prior distribution using geostatistical methods. For each model, we then apply two forward simulations: the first corresponds to the forward model of the data (past), the second corresponds to the forward model of the forecast (future). The relationship between observed data and forecast is generally highly non-linear, depending on the complexity of the prior distribution and the differences in the two forward operators. In order to derive a useful relationship, we first reduce the dimension of the data and the forecast through principal component analysis (PCA) related techniques in order to keep the most informative part of both sets. Then, we apply canonical correlation analysis (CCA) to establish a linear relationship between data and forecast in the reduced space components. If such a relationship exists, it is possible to directly sample the posterior distribution of the forecast with a multi-Gaussian framework. In this study, we apply this methodology to forecast the evolution with time of the distribution of temperature in a control panel in an alluvial aquifer. We simulate a heat tracing experiment monitored with both well logging probes and electrical resistivity tomography. We show (1) that the proposed method can be used to quantify the uncertainty on the forecast both spatially and temporally and (2) that spatially-distributed data acquired through geophysical methods help to significantly reduce the uncertainty of the posterior. [less ▲]

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See detailTime lapse imaging of water content with geoelectrical methods: on the interest of working with absolute water content data
Dumont, Gaël ULg; Pilawski, Tamara ULg; Robert, Tanguy et al

Poster (2016, April 21)

The electrical resistivity tomography is a suitable method to estimate the water content of a waste material and detect changes in water content. Various ERT profiles, both static data and time-lapse ... [more ▼]

The electrical resistivity tomography is a suitable method to estimate the water content of a waste material and detect changes in water content. Various ERT profiles, both static data and time-lapse, where acquired on a landfill during the Minerve project. In the literature, the relative change of resistivity ( Delta rho/rho ) is generally computed. For saline or heat tracer tests in the saturated zone, the Delta rho/rho can be easily translated into pore water conductivity or underground temperature changes (provided that the initial salinity or temperature condition is homogeneous over the ERT panel extension). For water content changes in the vadose zone resulting of an infiltration event or injection experiment, many authors also work with the Delta rho/rho or relative changes of water content Delta theta /theta (linked to the change of resistivity through one single parameter: the Archie’s law exponent “m”). This parameter is not influenced by the underground temperature and pore fluid conductivity ( rho_w) condition but is influenced by the initial water content distribution. Therefore, you never know if the loss of / signal is representative of the limit of the infiltration front or more humid initial condition. Another approach for the understanding of the infiltration process is the assessment of the absolute change of water content ( Delta theta ). This requires the direct computation of the water content of the waste from the resistivity data. For that purpose, we used petrophysical laws calibrated with laboratory experiments and our knowledge of the in situ temperature and pore fluid conductivity parameters. Then, we investigated water content changes in the waste material after a rainfall event ( Delta theta = Delta theta /theta * theta ). This new observation is really representatives of the quantity of water infiltrated in the waste material. However, the uncertainty in the pore fluid conductivity value may influence the computed water changes ( Delta theta =k*m*(rho_w)^1/2 ; where “m” is the Archie’s law exponent). Using these two complementary approaches, we analyzed the effect a major rainfall (20-30 mm in 2 hours) that occurred on the test site, characterized by a vegetalized and relatively dry zone and a devegatelized and humid zone. We intended to prove that most of the information contained in the Delta theta /theta distribution is the initial water content distribution in the ground.Water addition in dry zones resulting in large relative changes. The computation of the Delta theta is necessary to demonstrate preferential infiltration through the capping in a restricted zone of the vegetalized area. [less ▲]

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See detailAssessment of a design to monitor the influence of crop residue management on the dynamics of soil water content with ERT
Chelin, Marie ULg; Hiel, Marie-Pierre ULg; Hermans, Thomas ULg et al

Poster (2016, April 21)

Choices related to crop residue management affect the soil structure. As a consequence, they may determinethe spatio-temporal dynamics of water content and eventually the crop yields. In order to better ... [more ▼]

Choices related to crop residue management affect the soil structure. As a consequence, they may determinethe spatio-temporal dynamics of water content and eventually the crop yields. In order to better understand the influence of these strategies on hydraulic processes occurring at the plot scale, we opted for the use electrical resistivity tomography (ERT). This approach presents the advantage to limit soil disturbance but is still faced to important challenges when applied in an agricultural field context. Especially changing soil-electrode contact has to be considered, as it can lead to bad quality data, especially for setups with small electrodes and small inter-electrode distance. The objective of this study was to test the efficiency of a high-resolution 3-D field measurement design to properly assess the dynamics of soil water content. ERT measurements were conducted in a Cutanic Siltic Luvisol in Gembloux, Belgium, on two plots of 2m^2 ploughed in Oct 2014 at a depth of 25 cm and sown with maize in April 2015. The plants were removed on one of the plots in order to obtain a bare soil reference. A grid of 98 surface stainless steel electrodes was layed-out on each plot and four sticks supporting each eight stainless steel electrodes were vertically inserted into the soil up to 1.20 m to get more detailed information in depth. The experiments were performed between Jul and Oct 2015, in order to get measurements both in dry and wet periods. For surface and borehole monitoring, a dipole-dipole array configuration including in-line and cross-line measurements was adopted. Normal and reciprocal measurements were performed systematically to assess the data quality: only the datasets with a mean reciprocal error lower than 3% were considered for the data inversion. This contribution will show the first inverted results showing the complexity of experimental design and data analysis for high-resolution, timelapse ERT in field conditions. Based on these results, we will draw conclusions about a minimal data set to be obtained in our upcoming field experiments. [less ▲]

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See detailReconstruction of the Greenland ice sheet surface mass balance over 1900-2015 with the help of the regional climate MARv3.6 model
Fettweis, Xavier ULg; Agosta, Cécile ULg; Hubert, Gallée

Speech/Talk (2016)

With the aim of studying the recent Greenland ice sheet Surface Mass Balance (SMB) decrease with respect to the last century, we have forced the regional climate MAR model (version 3.6) with the ERA ... [more ▼]

With the aim of studying the recent Greenland ice sheet Surface Mass Balance (SMB) decrease with respect to the last century, we have forced the regional climate MAR model (version 3.6) with the ERA-Interim (1979-2015), ERA-40 (1958-2001), NCEP1 (1948-2015), NCEP2 (1979-2015), JRA-55 (1958-2015), 20CRv2(c) (1880-2012) and ERA-20C (1900-2010) reanalysis. While all of these forcing products are reanalyses, MAR simulates differences in SMB over the common period. A temperature correction of +1°C (resp. -1°C) had notably to be applied to the MAR boundary conditions given that ERA-20C (resp. 20CRv2) is ~1° colder (resp. warmer) over Greenland than ERA-Interim data over 1980-2010. Comparisons with PROMICE daily temperature measurements valid these corrections. In most of regions, the SMB discrepancies between the different simulations are not significant except in the South-East where the maximum of precipitation occurs and where SMB measurements are missing. This suggests that uncertainties in the current SMB reconstruction remain and that observations are still needed. Comparisons with SMB measurements from the PROMICE data set, ice cores and satellite derived melt extent allows to select the best reanalysis forced data set. All of these simulations show that i) the period 1961-1990 usually chosen as reference for SMB and ice dynamics (stable ice sheet) over Greenland is a period when the SMB was abnormally high in respect to the last 120 years; ii) SMB has been significantly decreasing after this reference period due to increasing melt. Both ERA-20C and 20CRv2 forced simulations suggest a precipitation increase since the beginning of the last century and the ERA-20C forced simulation only suggests that SMB during the 1920-1930 warm period over Greenland was comparable with the SMB of the 2000's. Finally, the sensitivity of switching on the erosion of the snow by the wind in MARv3.6 will be discussed. [less ▲]

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See detailVivre dans un film
Englebert, Jérôme ULg; Valentiny, Caroline

Scientific conference (2016, April 20)

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See detailSources pour l’étude des transferts de cultes en Grèce antique
Palamidis, Alaya ULg

Conference (2016, April 20)

A couple of Greek inscriptions show that it was possible to transfer a cult, that is to no longer honour a deity in their original sanctuary, but in a new one founded on this occasion at a different ... [more ▼]

A couple of Greek inscriptions show that it was possible to transfer a cult, that is to no longer honour a deity in their original sanctuary, but in a new one founded on this occasion at a different location. However, they provide few elements to study this phenomenon. The contribution of literary sources is also very limited. Thus, the 1st century A.D. author Strabo mentions four cases of cult transfers, which, however, prove not to correspond to historical events. We should therefore turn to archaeological sources, and especially to the negative evidence: the absence of archaeological material testifying to the frequentation of a sanctuary while the cult of the deity is still attested by other sources provides the best clue to such transfers. On the contrary, there is positive evidence for the relocation of temples, which were entirely taken down and reconstructed elsewhere — the so-called «Wandering temples» — but the reuse of building materials does not imply the transfer of the cult. Further indications that a cult was transferred include coins or even the orientation of temples. [less ▲]

Detailed reference viewed: 13 (0 ULg)