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See detailEvaluation of soil structural changes through macroscopic and microscopic measurement
Parvin, Nargish ULg; Degré, Aurore ULg; Chelin, Marie ULg et al

Poster (2015, April 16)

The heterogeneity of soil structure and pore size distribution are highly influenced by external factors like tillage systems and other agricultural management practices. However, changes in soil ... [more ▼]

The heterogeneity of soil structure and pore size distribution are highly influenced by external factors like tillage systems and other agricultural management practices. However, changes in soil hydrodynamic behavior are not fully understood and are still under research. Also, researchers have explained the impact of tillage practices on soil hydraulic properties related to pore size distribution, connectivity and orientation are involved but the characterization of these modifications and consequences remains a challenge. Furthermore, the relation between macroscopic measurements and microscopic investigation of the soil structure remains scarce. Recently, X-ray tomography (X- μCT) has been used in order to characterize changes in soil pore size distribution in various contexts and the method is able to link microtomography information to hydrodynamic measurement. In our study, X-μCT has been used in order to characterize changes in soil pore system. Since, tomography does not count most of the micropores, Richards’ pressure plate and evaporation method was also combined to get complete range of pore size distribution. We found good match between evaporation data with X-μCT at the macropore scale and evaporation data with pressure plate method at micropore scale. X-μCT data refines retention and hydraulic curves near saturation where Richards’ data alone can lead to numerous sets of fitted parameters. On the otherhand, evaporation data (Hyprop apparatus ©) provide comparable datasets with X-μCT. Combining micro and macroscopic measurements allows us to validate X-μCT information, which is otherwise not so obvious. [less ▲]

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See detailSnow cover evolution during the last fifty years in the Hautes Fagnes (Belgium) using the regional climate MAR model
Wyard, Coraline ULg; Fettweis, Xavier ULg; Erpicum, Michel ULg

Conference (2015, April 16)

The MAR model is a regional climate model originally developped for the polar regions to study the surface mass balance. In this study, the MAR model has been adapted to Belgium in order to study the snow ... [more ▼]

The MAR model is a regional climate model originally developped for the polar regions to study the surface mass balance. In this study, the MAR model has been adapted to Belgium in order to study the snow cover evolution of the Hautes Fagnes (south-east of Belgium), a region covered by snow one to two months per year. As validation, we have sucessfully compared MAR based daily snow heights with snowcam-based observations. Then, the model has been forced by ERA-Interim since 1958 to study the snow cover evolution during the last fifty years at the summit of Belgium. The results show non-significant trend. [less ▲]

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See detailCorrelation between levels of β-hydroxybutyrate and fatty acids in blood and milk and its impact on ketosis diagnosis in dairy cows
Lessire, Françoise ULg; Knapp, Emilie ULg; Dotreppe, Olivier et al

Poster (2015, April 16)

SKC at herd level is difficult to diagnose. Poor production and reproduction performances are usually observed as an increased incidence of periparturient diseases in the herd (Suthar et al., 2013 ... [more ▼]

SKC at herd level is difficult to diagnose. Poor production and reproduction performances are usually observed as an increased incidence of periparturient diseases in the herd (Suthar et al., 2013). Diagnosis methods include determination of beta-hydroxybutyrate (BHB) and increased non-esterified fatty acids (NEFA) resulting from body fat mobilization. BHB and NEFA could be dosed in blood of animals in late gestation and in early lactation. Post calving, cows presenting BHB over 1. 2-1.4 mmol/L are considered SCK-cows while those presenting NEFA over 0.6 mg/L are labelled fat mobilising cows. Development of non-invasive diagnosis techniques could be interesting to sample animals at a larger scale with lesser stress. The aim of this study was to verify whether blood and milk BHB values were correlated and whether diagnostic methods by milk analysis could be developed. Seventy -five cows out of 8 selected Walloon dairy herds were followed up monthly from calving to pregnancy diagnosis regarding production and reproduction. At each visit (V), BHB and NEFA levels were determined in milk and blood. A maximum of 5 V was made. BHB was determined in blood using a cow-side test and in milk by a colorimetric test . Blood NEFA and milk fatty acids were determined by gas chromatography (GC). Statistical analysis was performed by SAS 9.1. BHB levels in blood and milk were highly correlated (r= 0.86), indicating the possibility of diagnosis of SCK by milk sampling. The earliest the samples have been taken, the better the correlation is (r=0.95 V1; r = 0.91 V2). Comparison of BHB with NEFA demonstrated a better correlation with milk BHB than with blood BHB (respectively 0.51 and 0.53 in milk vs 0.41 and 0.48 in blood for the V1 and V2 respectively). After the 2d V, the correlation dropped to 0.38 (V3) and -0.14 (V4).To conclude, dosage of milk BHB could be a good indicator for ketosis diagnosis taking into account that correlation with blood BHB and with NEFA is time-related. [less ▲]

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See detailThe seamod.ro operational stochasting forecasting system of the Black Sea
Vandenbulcke, Luc ULg; Barth, Alexander ULg; Capet, Arthur et al

Poster (2015, April 15)

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See detailVariogram-based inversion of time-lapse electrical resistivity data: development and application to a thermal tracing experiment
Hermans, Thomas ULg; Nguyen, Frédéric ULg

Poster (2015, April 15)

Electrical resistivity tomography (ERT) has become a popular imaging methodology in a broad range of applications given its large sensitivity to subsurface parameters and its relative simplicity to ... [more ▼]

Electrical resistivity tomography (ERT) has become a popular imaging methodology in a broad range of applications given its large sensitivity to subsurface parameters and its relative simplicity to implement. More particularly, time-lapse ERT is now increasingly used for monitoring purposes in many contexts such as water content, permafrost, landslide, seawater intrusion, solute transport or heat transport experiments. Specific inversion schemes have been developed for time-lapse data sets. However, in contrast with static inversions for which many techniques including geostatistical, minimum support or structural inversion are commonly applied, most of the methodologies for time-lapse inversion still rely on non-physically based spatial and/or temporal smoothing of the parameters or parameter changes. In this work, we propose a time-lapse ERT inversion scheme based on the difference inversion scheme. We replace the standard smoothness-constraint regularization operator by the parameter change covariance matrix. This operator takes into account the correlation between changes in resistivity at different locations through a variogram computed using independent data (e.g., electromagnetic logs). It may vary for subsequent time-steps if the correlation length is time-dependent. The methodology is first validated and compared to the standard smoothness-constraint inversion using a synthetic benchmark simulating the injection of a conductive tracer into a homogeneous aquifer inducing changes in resistivity values of known correlation length. We analyze the influence of the assumed correlation length on inversion results. Globally, the method yields better results than the traditional smoothness constraint inversion. Even if a wrong correlation length is assumed, the method performs as well as the smoothness constraint since the regularization operator balances the weight given to the model constraint functional in the objective function. Then the methodology is successfully applied to a heat injection and pumping experiment in an alluvial aquifer. The comparison with direct measurements in boreholes (temperature loggers and distributed temperature sensing optic fibres) shows that ERT-derived temperatures and breakthrough curves image reliably the heat plume through time (increasing part of the curve, maximum and tail are correctly retrieved) and space (lateral variations of temperature are observed) with less spatial smoothing than standard methods. The development of new regularization operators for time-lapse inversion of ERT data is necessary given the broad range of applications where ERT monitoring is used. In many studies, independent data are available to derive geostatistical parameters that can be subsequently used to regularize geophysical inversions. In the future, the integration of spatio-temporal variograms into existing 4D inversion schemes should further improve ERT time-lapse imaging. [less ▲]

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See detailExperimental design to monitor the influence of crop residue management on the dynamics of soil water content
Chelin, Marie ULg; Parvin, Nargish ULg; Hiel, Marie-Pierre ULg et al

Poster (2015, April 15)

Choices related to crop residue management affecting soil structure determine spatio-temporal dynamics of water content and eventually crop yields. In this contribution, we discuss the experimental design ... [more ▼]

Choices related to crop residue management affecting soil structure determine spatio-temporal dynamics of water content and eventually crop yields. In this contribution, we discuss the experimental design we adopted to study the influence of three different agricultural management strategies (tillage and residue management) on the soil water dynamics under maize in a Cutanic Siltic Luvisol in Gembloux, Belgium. In order to limit soil disturbance, we opted for the use electrical resistivity tomography (ERT) and we use the bulk electrical conductivity as a proxy for soil moisture content. ERT is collected every week on a surface of two square meters corresponding to three rows of seven maize plants through surface stainless steel electrodes. Four additional sticks with stainless steel electrodes will be vertically inserted into the soil up to 1.20 m to get more detailed information near to the central maize row. In each of the monitoring plots, two time-domain reflectometry (TDR) probes will be installed for data validation. In order to calibrate the relationship between electrical resistivity and soil water content under highly variable field conditions (changes in soil structure, variable weather conditions, plant growth, fertilization), a trench will be dug, in which a set of four electrodes, one TDR probe and one temperature sensor will be placed at four different depths. In addition, two suction cups will be installed in each of the plots to quantify changes in ion composition and electrical conductivity of the soil solution at two different depths. Within the framework of the multidisciplinary research platform AgricultureIsLife, regular assessment of pore structure and crop developement will be conducted using X-ray images. Combining this wide range of data, we will be able to investigate and quantify the effect of simultaneously changing pore water conductivity, soil porosity, soil temperature and soil moisture on the effectiveness of time-lapse ER measurements as a proxy for soil moisture changes. [less ▲]

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See detailRegularized focusing inversion of time-lapse electrical resistivity data: an approach to parametrize the minimum gradient support functional
Nguyen, Frédéric ULg; Hermans, Thomas ULg

Poster (2015, April 15)

Inversion of time-lapse resistivity data allows obtaining ‘snapshots’ of changes occurring in monitored systems for applications such as aquifer storage, geothermal heat exchange, site remediation or ... [more ▼]

Inversion of time-lapse resistivity data allows obtaining ‘snapshots’ of changes occurring in monitored systems for applications such as aquifer storage, geothermal heat exchange, site remediation or tracer tests. Based on these snapshots, one can infer qualitative information on the location and morphology of changes occurring in the subsurface but also quantitative estimates on the degree of changes in certain property such as temperature or total dissolved solid content. Analysis of these changes can provide direct insight into flow and transport and associated processes and controlling parameters. However, the reliability of the analysis is dependent on survey geometry, measurement schemes, data error, and regularization. Survey design parameters may be optimized prior to the monitoring survey. Regularization, on the other hand, may be chosen depending on available information collected during the monitoring. Common approaches consider smoothing model changes both in space and time but it is often needed to obtain a sharp temporal anomaly, for example in fractured aquifers. We here propose to use the alternative regularization approach based on minimum gradient support (MGS) (Zhdanov, 2002) for time-lapse surveys which will focus the changes in tomograms snapshots. MGS will limit the occurrences of changes in electrical resistivity but will also restrict the variations of these changes inside the different zones. A common difficulty encountered by practitioners in this type of regularization is the choice of an additional parameter, the so-called , required to define the MGS functional. To the best of our knowledge, there is no commonly accepted or standard methodology to optimize the MGS parameter . The inversion algorithm used in this study is CRTomo (Kemna 2000). It uses a Gauss-Newton scheme to iteratively minimize an objective function which consists of a data misfit functional and a model constraint functional. A univariate line search is performed at each Gauss-Newton iteration step to find the optimum value of the regularization parameter  which minimizes the data misfit as a function of  while the data misfit is above the desired value and yields the desired target misfit (root-mean square value of error-weighted data misfit equal to 1) at the last iteration for a maximum value of . We propose here to optimize the  of the MGS functional by considering a univariate line search at the first iteration to find the  that minimizes the data misfit. The parameter is then kept constant during the Gauss-Newton iterative scheme. In this contribution, we validate our approach on a numerical benchmark and apply it successfully on a case study in the context of salt tracers in fractured aquifers. Zhdanov M.S. 2002. Geophysical Inverse Theory and Regularization Problems. Elsevier, Amsterdam, 628 p. Kemna A. 2000. Tomographic Inversion of Complex Resistivity - Theory and Application. PhD Thesis, Ruhr University Bochum. [less ▲]

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See detailFirst evidence of Neandertal cannibalism in Northern Europe: the case of the “Troisieme Caverne” of Goyet (Belgium)
Rougier, H.; Crevecoeur, I.; Beauval, C. et al

Conference (2015, April 15)

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See detailLIPOSOME CONTAINING ESTETROL FOR THE TREATMENT OF ISCHEMIA DISEASES IN PREMATURE BABIES
Palazzo, Claudio ULg; Karim, Reatul ULg; Mawet, Mawet et al

Poster (2015, April 14)

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See detailUse of NIR Hyperspectral Imaging and dichotomist classification tree based on SVM in order to discriminate roots and crop residues of winter wheat
Eylenbosch, Damien ULg; Fernández Pierna, Juan Antonio; Baeten, Vincent et al

Poster (2015, April 14)

NIR Hyperspectral Imaging coupled with SVM chemometric tool is proposed as an alternative method to the tedious and time-consuming hand sorting step needed before root quantification using the soil coring ... [more ▼]

NIR Hyperspectral Imaging coupled with SVM chemometric tool is proposed as an alternative method to the tedious and time-consuming hand sorting step needed before root quantification using the soil coring method. This method was applied to quantify roots under a winter wheat crop. [less ▲]

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See detailFuture projections of the Greenland ice sheet mass balance using the regional climate MAR model coupled with the GRISLI ice sheet model
Wyard, Coraline ULg; Fettweis, Xavier ULg; Ritz, Catherine

Poster (2015, April 14)

During the two last decades, the Greenland ice sheet (GrIS) contribution to the global mean sea level rise has significantly increased. But, difficulties remain to assess GrIS future contribution because ... [more ▼]

During the two last decades, the Greenland ice sheet (GrIS) contribution to the global mean sea level rise has significantly increased. But, difficulties remain to assess GrIS future contribution because of large uncertainties linked to the feedback between the surface mass balance (SMB) and GrIS topography changes. The regional climate MAR model has been coupled with the GRISLI ice sheet model, in order to account of this feedback in the future projections. The aim of this study is to assess the pertinence of the MAR-GRISLI coupling which requires long computation time. In order to identify GRISLI sensitivity to MAR forcing, GRISLI has been forced with various non-coupled (i.e. using a fixed topography), coupled and modified non-coupled MAR outputs. To adapt the non-coupled MAR outputs to the GRISLI topography changes, we use an interpolation technique based on SMB vs elevation vertical gradient. These experiences evaluate the performances/limits of this interpolation technique used to avoid a RCM-ice sheet model coupling. [less ▲]

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See detailUse of NIR-HIS and dichotomist classification tree based on SVMDA models in order to discriminate roots and crop residues of winter wheat
Eylenbosch, Damien ULg; Fernández Pierna, Juan Antonio; Baeten, Vincent et al

in EARSeL 2015: 9th EARSeL SIG Imaging Spectroscopy workshop, Luxembourg 14-16 April 2015 (2015, April 14)

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See detailOptical Study of a Spectrum Splitting Solar Concentrator based on a Combination of a Diffraction Grating and a Fresnel Lens
Michel, Céline ULg; Loicq, Jerôme ULg; Thibert, Tanguy ULg et al

Poster (2015, April 14)

This poster presents recent improvements of our new solar concentrator design for space application. The concentrator is based on a combination of a diffraction grating (blazed or lamellar) coupled with a ... [more ▼]

This poster presents recent improvements of our new solar concentrator design for space application. The concentrator is based on a combination of a diffraction grating (blazed or lamellar) coupled with a Fresnel lens. Thanks to this diffractive/refractive combination, this optical element splits spatially and spectrally the light and focus approximately respectively visible light and IR light onto electrically independent specific cells. It avoid the use of MJs cells and then also their limitations like current matching and lattice matching conditions, leading theoretically to a more tolerant system. The concept is reminded, with recent optimizations, ideal and more realistic results, and the description of an experimental realization highlighting the feasibility of the concept, and the closeness of theoretical and experimental results. [less ▲]

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See detailEGU2015 - ENSO forecast using a wavelet-based mode decomposition
Deliège, Adrien ULg; Nicolay, Samuel ULg; Fettweis, Xavier ULg

Conference (2015, April 13)

The aim of this work is to introduce a new method for forecasting major El Niño/ La Niña events with the use of a wavelet-based mode decomposition. These major events are related to sea surface ... [more ▼]

The aim of this work is to introduce a new method for forecasting major El Niño/ La Niña events with the use of a wavelet-based mode decomposition. These major events are related to sea surface temperature anomalies in the tropical Pacific Ocean: anomalous warmings are known as El Niño events, while excessive coolings are referred as La Niña episodes. These climatological phenomena are of primary importance since they are involved in many teleconnections ; predicting them long before they occur is therefore a crucial concern. First, we perform a wavelet transform (WT) of the monthly sampled El Niño Southern Oscillation 3.4 index (from 1950 to present) and compute the associated scale spectrum, which can be seen as the energy carried in the WT as a function of the scale. It can be observed that the spectrum reaches five peaks, corresponding to time scales of about 7, 20, 31, 43 and 61 months respectively. Therefore, the Niño 3.4 signal can be decomposed into five dominant oscillating components with time-varying amplitudes, these latter being given by the modulus of the WT at the associated pseudo-periods. The reconstruction of the index based on these five components is accurate since more than 93% of the El Niño/ La Niña events of the last 60 years are recovered and no major event is erroneously predicted. Then, the components are smoothly extrapolated using polynomials and added together, giving so several years forecasts of the Niño 3.4 index. In order to increase the reliability of the forecasts, we perform several months hindcasts (i.e. retroactive probing forecasts) which can be validated with the existing data. It turns out that most of the major events can be accurately predicted up to three years in advance, which makes our methodology competitive for such forecasts. Finally, we discuss the El Niño conditions currently undergone and give indications about the next La Niña event. [less ▲]

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See detailRetrieval of ammonia from ground-based FTIR measurements and its use for validation of satellite observations by IASI
Dammers, E; Palm, M; Warneke, T et al

in Geophysical Research Abstracts (2015, April 13), 17

Atmospheric Ammonia (NH3) has a major impact on human health and ecosystem services and plays a major role in the formation of aerosols [Erisman et al.,2013; Paulot and Jacob 2014]. NH3 concentrations are ... [more ▼]

Atmospheric Ammonia (NH3) has a major impact on human health and ecosystem services and plays a major role in the formation of aerosols [Erisman et al.,2013; Paulot and Jacob 2014]. NH3 concentrations are highly variable in space and time with overall short lifetime due to deposition and aerosol formation. The global atmospheric budget of nitrogen and in turn NH3 is still uncertain which asks for more ground-based and satellite observations around the world. Recent papers have described the possibility to measure NH3 with satellite infrared sounders which open up the way for calculations of global and regional nitrogen budgets [Clarisse et al 2009,Van Damme et al 2014a]. Validation of the satellite observations is essential to determine the uncertainty in the signal and its potential use. So far available surface layer observations of atmospheric NH3 concentrations have been used for comparisons with total columns retrieved from satellite observations [Van Damme 2014b]. We developed a retrieval for NH3 column density concentrations (molecules NH3/cm2) by fitting a set of spectral windows to ground-based solar absorption Fourier transform infrared (FTIR) measurements with the spectral fitting program SFIT4 [Hase et al., 2004]. The retrieval is then applied to FTIR measurements from a set of spectrometer sites from the Network for detection of Atmospheric Composition Change (NDACC) to retrieve NH3 columns for the sites located in Bremen, Germany; Lauder, New Zealand; Jungfraujoch, Switzerland; and the island of Reunion, France. Using eight years (2005-2013) of retrieved NH3 columns clear seasonal cycles are observed for each of the stations. Maximum concentrations can be related to NH3 emission sources, specific for the regions. A comparison between the retrieved NH3 columns and observations from the recent IASI- NH3 product [Van Damme et al, 2014a] using strict spatial and temporal criteria for the selection of observations showed a good correlation (R=0.82; slope=0.63). The IASI- NH3 columns for the Bremen and Lauder area show similar temporal cycles when compared to the FTIR observations. [less ▲]

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See detailPreliminary results for a hydrogen maser cavity in the TE111 mode
Van Der Beken, Emeline ULg; Léonard, Daniel; Counet, Arnaud et al

Poster (2015, April 13)

An analysis of a hydrogen maser working with an unusual TE111 mode is presented. Different simulations have been carried out and are compared with preliminary results obtained for such a maser. In ... [more ▼]

An analysis of a hydrogen maser working with an unusual TE111 mode is presented. Different simulations have been carried out and are compared with preliminary results obtained for such a maser. 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. [less ▲]

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See detailHalogenated source gases measured by FTIR at the Jungfraujoch station: updated trends and new target species
Mahieu, Emmanuel ULg; Bader, Whitney ULg; Bovy, Benoît ULg et al

in Geophysical Research Abstracts (2015, April 13), 17

In this contribution, we present decadal time series of halogenated source gases monitored at the high altitude station of the Jungfraujoch (46.5°N, 8°E, 3580 m asl) with Fourier Transform Infared (FTIR ... [more ▼]

In this contribution, we present decadal time series of halogenated source gases monitored at the high altitude station of the Jungfraujoch (46.5°N, 8°E, 3580 m asl) with Fourier Transform Infared (FTIR) spectrometers, within the framework of the Network for the Detection of Atmospheric Composition Change. Total column trends presented in previous studies for CFC-11, -12 and HCFC-22, CCl4, HCFC-142b, CF4 and SF6 will be updated using the latest available Jungfraujoch solar observations. Investigations dealing with the definition of approaches to retrieve additional halogenated source gases from FTIR spectra will also be evoked. Our trend results will be critically discussed and compared with measurements performed in the northern hemisphere by the in situ networks. [less ▲]

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See detailA short dive into the complexity of Jupiter’s aurorae - invited
Bonfond, Bertrand ULg

Conference (2015, April 13)

Aurorae are the atmospheric signatures of energetic processes taking place far in the magnetosphere. One of the most important results brought by high resolution imaging of the UV aurorae at Jupiter is ... [more ▼]

Aurorae are the atmospheric signatures of energetic processes taking place far in the magnetosphere. One of the most important results brought by high resolution imaging of the UV aurorae at Jupiter is the realization that there isn’t such a thing as «the aurora» at Jupiter; as these light emissions appear to arise from a variety of processes. Some are related to the interaction of the magnetospheric plasma with the moons (the satellite footprints). Others are linked with the radial motion of flux tubes through centrifugal instabilities (the injection auroral signatures). Some diffuse emissions are connected with wave-particle interaction (the equatorward diffuse emissions). Another feature is associated with the magnetosphere-ionosphere coupling (the main emission/oval). Some auroral spots are related to internally driven reconnection (the polar dawn spots). Finally, the polar-most emissions remain to be understood and this list is still incomplete. In order to illustrate the discrepancies between these various features, I will show a set of recent results derived from the analysis of Hubble Space Telescope observations. For example, I will compare the vertical profile of satellite footprints and the main emissions, and show that the energy population of the precipitating particles varies from feature to feature. Moreover, even within a single feature, spatial variations do exist. As an example, I will characterize the dawn-dusk brightness discrepancy of the main emissions and discuss its implication regarding the magnetospheric currents. And finally, the dynamics of the features also helps differentiating one type of aurora from another. This will be shown through the description of the morphological evolution of the transient flares in the polar region. [less ▲]

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See detailSoil porosity in agricultural context: A review of measurement techniques at various scales
Garré, Sarah ULg; Chelin, Marie ULg; Luong, Jeanne ULg et al

Poster (2015, April 13)

Soil compaction was identified by European Commission as one of the eight main threats for agricultural soils. In order to address this issue, measurements of soil porosity are critical. However, there ... [more ▼]

Soil compaction was identified by European Commission as one of the eight main threats for agricultural soils. In order to address this issue, measurements of soil porosity are critical. However, there are as many techniques to measure as there are definitions of porosity. A single method is not sufficient to obtain a complete image of the soil porosity at various scales and encompassing different levels of complexity. Each existing method is characterized by a unique combination of a specific level of complexity, resolution and scale of measurement. In this review, we started by defining the basic terms linked to soil porosity in an agricultural context. Then we give an overview of relevant measurement techniques, from classical methods to recent advances. We present their advantages and disadvantages, the scales of measurement, the resolution, the expected accuracy and the susceptibility to errors. This work aims at guiding the choice for the best (combination of) technique(s) to answer questions related to agricultural soil porosity, categorizing techniques according to the parameters they focus on: from total porosity over pore size distribution, structure and connectivity up to the quantification of spatio-temporal dynamics. [less ▲]

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See detailRecent increase of ethane detected in the remote atmosphere of the Northern Hemisphere
Franco, Bruno ULg; Bader, Whitney ULg; Bovy, Benoît ULg et al

Conference (2015, April 13)

Ethane (C2H6) has a large impact on tropospheric composition and air quality because of its involvement in the global VOC (volatile organic compound) – HOx – NOx chemistry responsible for generating and ... [more ▼]

Ethane (C2H6) has a large impact on tropospheric composition and air quality because of its involvement in the global VOC (volatile organic compound) – HOx – NOx chemistry responsible for generating and destroying tropospheric ozone. By acting as a major sink for tropospheric OH radicals, the abundance of C2H6 influences the atmospheric content of carbon monoxide and impacts the lifetime of methane. Moreover, it is an important source of PAN, a thermally unstable reservoir for NOx radicals. On a global scale, the main sources of C2H6 are leakage from the production, transport of natural gas loss, biofuel consumption and biomass burning, mainly located in the Northern Hemisphere. Due to its relatively long lifetime of approximately two months, C2H6 is a sensitive indicator of tropospheric pollution and transport. Using an optimized retrieval strategy (see Franco et al., 2014), we present here a 20-year long-term time series of C2H6 column abundance retrieved from ground-based Fourier Transform InfraRed (FTIR) solar spectra recorded from 1994 onwards at the high-altitude station of Jungfraujoch (Swiss Alps, 46.5° N, 3580 m a.s.l.), part of the Network for the Detection of Atmospheric Composition Change (NDACC, see http://www.ndacc.org). After a regular 1994 – 2008 decrease of the C2H6 amounts, which is very consistent with prior major studies (e.g., Aydin et al., 2011; Simpson et al., 2012) and our understanding of global C2H6 emissions, trend analysis using a bootstrap resampling tool reveals a C2H6 upturn and a statistically-significant sharp burden increase from 2009 onwards (Franco et al., 2014). We hypothesize that this observed recent increase in C2H6 could affect the whole Northern Hemisphere and may be related to the recent massive growth in the exploitation of shale gas and tight oil reservoirs. This hypothesis is supported by measurements derived from solar occultation observations performed since 2004 by the Atmospheric Chemistry Experiment – Fourier Transform Spectrometer (ACE-FTS) instrument and at other NDACC sites, namely Toronto (44° N) and Thule (77° N). Indeed, the recent rates of changes characterizing these data sets are consistent in magnitude and sign with the one derived from the FTIR measurements at Jungfraujoch. In contrast, the ethane time series form Lauder (45° S) shows a monotonic decrease over the last two decades. Investigating both the cause and impact on air quality of the C2H6 upturn should be a high priority for the atmospheric chemistry community. [less ▲]

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See detailOrganic and inorganic carbon fluxes in a tropical river system (Tana River, Kenya) during contrasting wet seasons
Geeraert, N; Omengo, FO; Bouillon, S et al

Poster (2015, April 12)

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See detailHow phosphorus limitation can control climatic gas emission
Gypens; Borges, Alberto ULg; Speeckaert, Gaëlle ULg et al

Conference (2015, April 12)

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See detailUrban Greening Processes in Old Industrial Cities in Belgium: Factors of Success in Restoring Quality of Life and Combatting Environmental Inequalities
Lejeune, Zoé ULg

Conference (2015, April 11)

Environmental justice/inequality (EJ/I) movements, first in the US, then in many other countries have sought to shed light on the unequal environmental situations burdened by poor populations and ethnic ... [more ▼]

Environmental justice/inequality (EJ/I) movements, first in the US, then in many other countries have sought to shed light on the unequal environmental situations burdened by poor populations and ethnic minorities, and to challenge public policies and their unfair impact on those groups. In continental Europe and more specifically in Belgium, EJ activism has not emerged as a specific frame for environmental and urban contention. Locating this research at the interface of environmental inequality and urban environmental planning, we present findings from qualitative analysis gathered through interviews with local stakeholders be they elected officials, local officers, non-profit, or residents (n=30); our purpose is to ask how social movements as well as public authorities and ordinary citizens manage to reverse urban decline in old industrial cities in Belgium through environmental channels. These cities are characterized by environmental degradation and inequalities: atmospheric and soil pollution, brownfields, and high rates of unemployment, poverty, and social exclusion. We are interested in urban environmental processes, and explore the following question: what are the factors of success in restoring quality of life and wellbeing in two Belgian cities, with different mobilization profiles – one is successful, the other not – putting into perspective the determinants of successful renewal processes? We are particularly interested in understanding how environmental (inequality) issues are framed and handled politically at the local scale within those cities? The underlying goal consists of defining and formalizing new spaces and configurations of multilevel regulation between stakeholders, acting scale to revitalize their environment and their city or neighborhood, and to improve current urban policies in order to reduce environmental inequalities. Key findings are divided into five main explanatory categories: political opportunity structure; non-profit sector organization; citizens’ characteristics and collective action framework; bureaucratic reform; and symbolic action. [less ▲]

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Peer Reviewed
See detailWhat is the professional profile of patients in phoniatrics?
Remacle, Angélique ULg; Petitfils, Cloé; LEJEUNE, LIONEL ULg et al

Conference (2015, April 10)

Objective. Research has paid increased attention to occupational voice disorders. This study describes the occupational status of patients examined in the Department of Otorhinolaryngology at Liège ... [more ▼]

Objective. Research has paid increased attention to occupational voice disorders. This study describes the occupational status of patients examined in the Department of Otorhinolaryngology at Liège University Hospital (Belgium) from 2009 to 2013. Study design. Retrospective study. Methods. The sex, age, diagnosis and occupational status were identified for 1,079 patients who were examined for a voice problem (754 women and 325 men; ages 4 to 93). The diagnosis was established using videolaryngostroboscopy. For patients who were employed, we identified (1) the numerically most frequent professionals, and (2) the professionals most at risk of consulting for their voice, based on the distribution of these professions among all workers living in French-speaking Belgium. Results. 11% of patients were unemployed, 15% were students, 20% were retired, and 54% were workers. In decreasing order of frequency, the most commonly seen professionals were teachers, office workers, artists (singers, actors, and musicians), storekeepers and marketing representatives, managers, domestic workers, and laborers. Regarding their distribution in the working population, the workers at greatest risk of consulting were artists, music teachers, counselors, sports coaches, psychologists, switchboard operators, journalists, and teachers. Nodules are the most common pathologies, encountered in 16.8% of the workers and 42.8% of the students who consulted the Department of Otorhinolaryngology for dysphonia. Conclusion. Prevention is needed both for the professions that seek medical help in the largest numbers (teachers) and for those that are at highest risk of consulting (artistic professions). In addition, teachers must be informed of the need to seek help as soon as voice problems appear. Level of evidence: 2b [less ▲]

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See detailEstimated Subglottic Pressure Evaluation, Evolution in 152 Dysphonic Patients
Morsomme, Dominique ULg; Finck, Camille ULg; Larrouy, Pauline ULg

Conference (2015, April 08)

Background: Estimated subglottic pressure (ESGP) is part of the aerodynamic measurements included in the vocal profile. It is an indication of vocal effort. Speyer reports an improvement of the ESGP score ... [more ▼]

Background: Estimated subglottic pressure (ESGP) is part of the aerodynamic measurements included in the vocal profile. It is an indication of vocal effort. Speyer reports an improvement of the ESGP score after voice treatment. Nevertheless, few studies used ESGP to evaluate voice efficiency treatment. Objectives: The purpose is to examine the ESGP twice, at the first (T1) and the last consultation (T2) . We observe the ESGP values according to voice pathology. We also examine the relationships between ESGP, SPL(Sound pressure level) and DSI (Discorder severity index) . Method: The study includes 130 patients (M:31/W:99), which suffer from 4 different pathologies as immobility (N: 54), oedema (N:23), nodules (N:24) and polyp (N:29). Each patient’s file consists of VLS, acoustic, aerodynamic and perceptual measures. The ESGP was collected through the Phonatory Aerodynamic System Model 6600 (KayPentax). Patients produced 3 sequences of / ipipi / at low (IL), conversational (IC) and high (IH) intensity. Patients were grouped according to the ENT’s diagnosis. We compare our values to those of Zraick et al (2012) which studied ESGP on a healthy group. Results: At T2, for the all patients, at minimum and conversational intensity the ESGP scores decrease singificantly, even if those scores were higher than for the healthy group. We observe a negative correlation between ESGP and SPL at low and conversational intensity. At T1, the higher is the ESGP score, the lower is the SPL score. At T2, the higher is the ESGP score, the higher is the SPL score. At T1, a negative correlation is observed between ESGP and DSI for 2 groups of patients (immobility and polyp) only at minimum intensity. The higher is the ESGP, the lower is SPL. At T2, only for the group immobility, the negative correlation persists. Conclusion: This study highlights the importance of considering the ESGP as a parameter of efficiency. High ESGP is mainly connected with patients who suffer from pathology. The patient who suffer from immobility seems to present a specific profile which could help the clinician to better understand their vocal behavior. Recommendation: This study highlights the pertinence of considering the ESGP as a parameter of vocal treatment efficiency. [less ▲]

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See detailAging Mechanisms in Amorphous GeTe
Raty, Jean-Yves ULg; Zhang, Wei; Luckas, Jennifer et al

Conference (2015, April 08)

We investigate the structure of amorphous GeTe using Density Functional Theory based Molecular Dynamics, using either the standard Generalized Gradient Approximation, or the more elaborate Van der Waals ... [more ▼]

We investigate the structure of amorphous GeTe using Density Functional Theory based Molecular Dynamics, using either the standard Generalized Gradient Approximation, or the more elaborate Van der Waals approximation. New insight is provided on the stability of homopolar GeGe bonds and tetrahedral Ge bonding, in relation with the resistance drift phenomenon, that is investigated experimentally using photothermal deflection spectroscopy experiments. Aging phenomena are common to all amorphous structures, but of special importance in phase change materials (PCM) since it impedes the realization of multi-level memories. Different interpretations have been proposed, but we focus here on the structural relaxation of amorphous GeTe, chosen because it is the simplest system that is representative of the wider class of GST alloys, lying along the GeTe-Sb2Te3 composition line of the GeSbTe phase diagram. Since the structural relaxations concerned with the drift take place on long time scales, the task of understanding them to limit their consequences is not a simple one. We successfully achieved this goal by developing new approaches to overcome a series of hurdles. A first problem is that directly generating an amorphous structure by quenching a liquid using Density Functional Theory (DFT) based Molecular Dynamics leads to one sample with a small number of atom (typically a few hundreds), and, hence of small number of atomic environments. Here we sample a large number of local atomic environments, corresponding to different bonding schemes, by chemically substituting different alloys, selected to favor different local atomic structures. This enables spanning a larger fraction of the configuration space relevant to aging. A second aspect is that GST alloys are known to display complex bonding mechanisms, for which the simple chemist’s “octet-rule” does not apply, leading a long series of controversies, concerning in particular the local structure around Ge atoms. We overcome this problem by using state of the art non local DFT-MD, including the so-called van der Waals corrections. This leads to more clearly defined environments that are thoroughly analyzed. We can then identify their fingerprints in the available structural experimental data and assess the stability of these local environments to obtain information of the driving forces leading to the structural relaxation. The calculated electronic properties nicely match the most recent photothermal deflection spectroscopy experiments that are presented here. Our results support a model of the amorphous phase and its time evolution that involves an evolution of the local (chemical) order towards that of the crystal (by getting rid of homopolar bonds), and an evolution of its electronic properties that drift away from those of the crystal, driven by an increase of the Peierls-like distortion of the local environments in the amorphous, as compared to the crystal. [less ▲]

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See detailState of the art on drivers of deforestation in the Congo basin tropical forest
Gillet, Pauline ULg; Vermeulen, Cédric ULg; Dessard, Hélène et al

Conference (2015, April 07)

The Congo basin forest experiment a low pressure on biodiversity in comparison to other rainforests around the world. But according to the predictions, climate change and direct human drivers could have ... [more ▼]

The Congo basin forest experiment a low pressure on biodiversity in comparison to other rainforests around the world. But according to the predictions, climate change and direct human drivers could have an important effect on the deforestation rate. In that context, CoForTips project want to foster a better management of the Congo Basin forests through a better understanding of the dynamics, regime shifts and tipping points of biodiversity and a better definition of the conditions of resilience of social and ecological systems. In order to assess the current knowledge about drivers of deforestation in the world tropical forests, we analyzed the existent literature to list the direct and indirect drivers of deforestation in the forested tropical zones and to focus on deforestation in the Congo Basin forest and specifically in Cameroon and Gabon. We listed direct drivers of deforestation like expansion of agriculture which can be either family farming or agribusiness; timber extraction for softwood industry and fuel wood; development of infrastructure leading to the opening up of forested land and populations, and mining industries. The underlying causes found in the literature concern economic factors like gross domestic product, national income based on environmental resources exploitation and consumer demand expressing on local and global markets. Technological factors that allow much larger removal. Cultural issues like representation of the forest in the collective imagination as an important source of economic income. Institutional factors like policy measures advocating pro-deforestation measures and demographic causes taking into account for local population rise due to a high fertility rate and linked to population migration. Those direct and underlying causes of deforestation where then detailed for Cameroon and Gabon. [less ▲]

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See detailStone tool hafting and use in the European Upper Palaeolithic: first results from Hohle Fels
Taipale, Noora ULg; Rots, Veerle ULg

Poster (2015, April 07)

European Upper Palaeolithic lithic assemblages have been so far defined largely on a typological or technological basis, whereas extensive studies that would utilise the full potential of functional ... [more ▼]

European Upper Palaeolithic lithic assemblages have been so far defined largely on a typological or technological basis, whereas extensive studies that would utilise the full potential of functional analysis have been few. In this poster, I will present the outline and first results of an ongoing PhD project dedicated to the variability in stone tool use and hafting in the Upper Palaeolithic of Central and Western Europe. Recent methodological developments have made possible the distinction between hafted and hand-held tools and the identification of different hafting modes in archaeological assemblages. The aim of my research is to understand the main developments and regional patterns in tool hafting and use in the Gravettian and Magdalenian, and evaluate their impact on lithic assemblage variability. The cave site Hohle Fels serves here as a case study, and the first results of the analysis of the site’s Gravettian material will be used to illustrate the potential of this kind of approach in the study of past human behaviour, cognition and culture. [less ▲]

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See detailTree models with Scikit-Learn: Great models with little assumptions
Louppe, Gilles ULg

Conference (2015, April 03)

This talk gives an introduction to tree-based methods, both from a theoretical and practical point of view. It covers decision trees, random forests and boosting estimators, along with concrete examples ... [more ▼]

This talk gives an introduction to tree-based methods, both from a theoretical and practical point of view. It covers decision trees, random forests and boosting estimators, along with concrete examples based on Scikit-Learn about how they work, when they work and why they work. [less ▲]

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See detailLire le futur du passé: villes et paysages de Meuse en projet
Occhiuto, Rita ULg

Conference (2015, April 03)

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See detailApplication of stable isotopes in trophic ecology: importance of TEF and seasonal baseline for robust interpretations.
Remy, François ULg; Darchambeau, François ULg; Dauby, Patrick ULg et al

Conference (2015, April 02)

Nitrogen, carbon and sulfur stable isotopes are very powerful tools for trophic ecologists to delineate food webs of various ecosystems. More recently… the use of mixing models has exponentially increased ... [more ▼]

Nitrogen, carbon and sulfur stable isotopes are very powerful tools for trophic ecologists to delineate food webs of various ecosystems. More recently… the use of mixing models has exponentially increased to give a more specific vision of organism’s diets and trophic relationships. Two case studies will be presented to give a summary of what’s been done in Liège Oceanology Lab to improve our interpretation of stable isotopes results. First is an experimental calculation of the Trophic Enrichment Factors (TEFs) for one dominant detritivorous species of Mediterranean amphipod inhabiting seagrass detritus: Gammarus aequicauda (Martynov, 1931). This experimental study was planned after a strange result of the SAIR mixing model, giving results opposed to all observations and knowledge we had about this species. Thus, the impact of 3 very different food sources (amphipod powder, algae power, seagrass powder) on the turnover rate of C and N isotopic compositions was tested, and afterwards TEFs for C and N for each source were calculated. Animal food source showed to be the most effectively assimilated with a fast turnover rate while seagrass and algae showed very slow assimilation. TEFs calculations showed to be interesting because TEFs seem not to depend on the natural feeding type of the invertebrate but more on the type of food source. Animal source showed carnivorous TEFs values while seagrass and algae source showed typical detritivorous values. SIAR results with these new custom values gave more coherent values highlighting the major importance of TEFs values for mixing models data interpretation. Second is a simple question: are the seasonal isotopic composition variations observed for many seagrass detritus macrofauna species due to actual diet changes, or only to isotopic baseline shift of the food sources? Macrofauna and all potential food sources were sampled near STARESO Oceanographic Station (Corsica, 8°45’E; 42°35’N) in 2011-2012 at each season at two different sites. SIBER software runs with C and N isotopic data showed spatio-temporal isotopic variations at community, interspecific and intraspecific level. SIBER did not gave us information about the origin of these changes, but coupled with SIAR and our custom TEFs, species actually showing drastic changes of diet were identified, while others seem to reflect more a source baseline isotopic composition shift. Working at specific level is compulsory for fine conclusions. These two case studies highlight the importance of mixing model use and of accurate TEF values to run these models properly to draw robust and reliable conclusions using stable isotopic data. [less ▲]

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See detailDoes high school program choice affect academic performance? Evidence for Economics
Lefevre, Mélanie ULg

Conference (2015, April 02)

This study evaluates the impact of the choice of the Economics elective course in secondary school on the performance in Economics at the University level. While several studies look at the impact on ... [more ▼]

This study evaluates the impact of the choice of the Economics elective course in secondary school on the performance in Economics at the University level. While several studies look at the impact on performance of the number of hours of mathematics in secondary school, less has been made regarding the impact of the secondary school Economics program. We match survey data from 360 students enrolled in the first year of the bachelors program in HEC-Management School of University of Liège, with administrative data and exam results. The methodological challenge is that students who choose Economics elective course in secondary school are likely to be different, in terms of motivation, from other students. To get rid of this potential bias, we approximate motivation using self-reported reasons for the choice of the elective courses, but also participation to non-mandatory tests and preparations before the exam. We also control for several individual characteristics (socio-economic background, age, gender, secondary school fixed effect, etc.) in order to compare students with similar abilities. Preliminary analysis shows that students who have chosen Economics elective course in the last year of secondary school do not perform better, or worse, at their University Economics exam, when controlling for the number of hours of mathematics they had in secondary school, as well as other individual characteristics. However, they are less likely to report their bachelor Economics course as being “difficult”. Overconfidence of students with higher previous economic knowledge may explain why they do not perform better than their peers. [less ▲]

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See detailMultitasking abilities in persons diagnosed with schizophrenia: a new tool and cognitive model.
Laloyaux, Julien ULg; Van der Linden, Martial ULg; Laroi, Frank ULg

Poster (2015, April 01)

Difficulties in everyday life activities are core features of persons diagnosed with schizophrenia, and in particular during multitasking activities (Semkovska et al., 2010). Multitasking refers to ... [more ▼]

Difficulties in everyday life activities are core features of persons diagnosed with schizophrenia, and in particular during multitasking activities (Semkovska et al., 2010). Multitasking refers to activities (e.g. preparing a meal) where the person has to: (a) carry out and alternate between different tasks that vary in terms of priority, difficulty and duration; (b) define the tasks’ targets; (c) and where the person is faced with unexpected problems during the realization of these tasks (Burgess, 2000). However, the cognitive underpinnings of multitasking abilities have never been adequately explored in schizophrenia. Further, only two cognitive models exist in the literature, which are based on student (Logie et al., 2011) and neurological (Burgess et al., 2000) samples. Both of these models suggest three primary constructs: Memory, Planning and Intent. There are, however, several limitations related to the way multitasking abilities were evaluated in these studies. We thus developed a computerized real-life activity task - the Computerized Meeting Preparation Task (CPMT), which was specifically designed to take into account the multitasking nature of certain everyday life activities. Using this task, and based on previous studies (Burgess et al., 2000; Logie et al., 2011), the aim of the present study was to evaluate multitasking abilities in schizophrenia and to do so in a new cognitive model of multitasking that takes into account certain cognitive functions that are not integrated in existing models. Methods: Fifty-seven individuals with schizophrenia and 41 matched healthy controls completed the CMPT. Participants were also evaluated with a battery of cognitive tests. Results: The results suggest that the CMPT possesses good sensitivity and confirmed the three underlying constructs of multitasking (Memory, Planning and Intent), which were found to be underpinned by several cognitive functions and multitasking aspects. Conclusion: Taken together, this new cognitive model and the CMPT could be a good basis for cognitive interventions of multitasking abilities in schizophrenia. Burgess, P.W., 2000. Strategy application disorder: the role of the frontal lobes in human multitasking. Psychol Res 63, 279-288. Logie, R., et al., 2011. Multitasking: multiple, domain-specific cognitive functions in a virtual environment. Mem Cogn 39, 1561-1574. Semkovska, M. et al., 2004. Assessment of executive dysfunction during activities of daily living in schizophrenia. Schizophr Res 69, 289-300. [less ▲]

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See detailAssociation of classical microbiology and 16S rDNA metagenetic Aanalysis to evaluate the presence of Clostridium difficile ina a belgian nursing home
Rodriguez Diaz, Cristina ULg; Taminiau, Bernard ULg; Avesani, Véronique et al

Poster (2015, April 01)

Increasing age, several co-morbidities, environmental contamination, antibiotic exposure and other intestinal perturbations appear to be the greatest risk factors for C. difficile infection (CDI ... [more ▼]

Increasing age, several co-morbidities, environmental contamination, antibiotic exposure and other intestinal perturbations appear to be the greatest risk factors for C. difficile infection (CDI). Therefore, elderly care home residents are considered particularly vulnerable to CDI. The main objective of this study was to evaluate and follow the prevalence of C. difficile in a Belgian nursing home. During a 4-month period, stool samples from a group of 23 elderly care home residents were collected weekly. A C. difficile microbiological detection scheme was performed along with an overall microbial biodiversity study of the faeces content by Targeted Metagenomic analysis. Culture of samples was performed in a selective medium cycloserine cefoxitin fructose cholate. An identification of the isolated colonies was done by PCR detection of tpi, tcdA, tcdB and cdtA genes. Toxic activity was confirmed by a cytotoxic immunoassay. Further characterization was performed by PCR ribotyping. The Metagenomic analysis was targeted on the v1-v3 hyper-variable region of 16S rDNA. The taxonomical assignment of the populations was performed with MOTHUR and Blast algorithms. Seven out of 23 (30.4%) residents were (at least one week) positive for C. difficile. The most common PCR-ribotype identified was 027. Targeted Metagenomic analyses reveals that each resident has his own bacterial imprint, which is stable during the entire study. Residents’ positives for C. difficile by classical microbiology showed an important proportion of C. difficile sequences. However, Metagenomics analysis can’t substitute targeted protocols. It was not used as a diagnostic tool to detect C. difficile but rather to determine the identification and correlations of the major bacterial populations that are present in the gut microbiota. In conclusion, this unique association of classical microbiology protocol with pyrosequencing allowed to follow C. difficile in patients and to identify several other bacterial populations whose abundance is correlated with C. difficile. [less ▲]

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See detailLes voix du lecteur dans la presse française au XIXe siècle: introduction et conclusions
Stienon, Valérie ULg; Absalyamova, Elina

Conference (2015, April)

Le XIXe siècle est assurément l’âge de la lecture. Traversé par un double mouvement d’alphabétisation et de croissance démographique, il voit le lectorat s’étendre à de nouvelles catégories de personnes ... [more ▼]

Le XIXe siècle est assurément l’âge de la lecture. Traversé par un double mouvement d’alphabétisation et de croissance démographique, il voit le lectorat s’étendre à de nouvelles catégories de personnes : ouvriers, femmes, enfants. Dans les foyers, les cafés, les cercles et les cabinets de lecture, c’est l’imprimé à diffusion périodique qui attire à lui l’essentiel de ce nouveau public. Le journal offre une alternative majeure au livre, moins coûteuse et plus accessible. Plus immédiate, aussi, puisqu’il construit avec ses destinataires un système d’adresses et de réponses autour de l’actualité socioculturelle. Du courrier des lecteurs au droit de réponse, en passant par la causerie, le badinage, la note et la lettre ouverte, variés sont les moyens dont il dispose pour donner, réellement ou fictivement, la parole à ses lecteurs. Plus qu’une figure de récepteur à émouvoir, éduquer ou moraliser, le lecteur devient véritablement une « voix » qui investit les nouveaux espaces d’expression de la civilisation du journal alors en constitution en France. Commenter les faits divers, orienter l’intrigue duroman-feuilleton et réagir à la parution d’une oeuvre deviennent autant d’initiatives accessibles au plus grand nombre. En associant l’étude des imaginaires médiatiques à la poétique du support et à l’histoire culturelle, ces deux journées ont pour objectif d’éclairer les rôles et les statuts du lectorat tels qu’ils sont décelables dans la textualité du journal. Que nous apprend celle-ci sur laparticipation des lecteurs au dialogue créatif avec les producteurs, à la configuration des genres, à la promotion des oeuvres, aux définitions de l’écrivain en régime médiatique ? [less ▲]

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See detailGAIMS: a tool specifically developed for the clinical gait analysis of patients with multiple sclerosis
Pierard, Sébastien ULg; Phan-Ba, Rémy; Giet, Amaury et al

in Multiple Sclerosis Journal (2015, April), 21(4), 498-499

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See detailBaseline Fibulin3 concentrations are associated with incidence of clinical knee OA after 30 months in overweight and obese women
Runhaar, Jos; Sanchez, Christelle ULg; Henrotin, Yves ULg et al

in Osteoarthritis and Cartilage (2015, April), 23(S2), 83

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See detailFavorinos d'Arles et ses contemporains : bilinguisme et biculturalisme au IIe siècle apr. J.-C.
Rochette, Bruno ULg

in Marganne, Marie-Hélène; Amato, Eugenio (Eds.) Le traité sur l'exilde Favorinos d'Arles. Papyrologie, Philologie et littérature (2015, April)

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See detailNumerical prediction of resulting rollover shapes and sheared edges after blanking process
Canales Cardenas, Cristian ULg; Boman, Romain ULg; Bussetta, Philippe et al

Conference (2015, April)

Over the years, the simulation of manufacturing processes has introduced several numerical challenges for researchers in computational mechanics. In particular, the numerical modeling of sheet metal ... [more ▼]

Over the years, the simulation of manufacturing processes has introduced several numerical challenges for researchers in computational mechanics. In particular, the numerical modeling of sheet metal blanking process involves different numerical issues that must be carefully treated: a large and highly localized deformation in the shearing zone prior to fracture, complex contact interactions between the tools and the metallic sheet and finally, the ductile failure phenomenon. Despite that this process is one of the most widely used cutting techniques for mass production, the process parameters are normally set by empirical evidence due to the physical complexity resulting from the extreme amount of shearing involved. In addition, the strain-rate dependent behavior of the material must be taken into account due to high punch velocities encountered in practice. Thus, an accurate numerical tool is extremely desirable to optimize the setting parameters of this technique and will lead to a better understanding of the process. [less ▲]

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See detailTracking Middleboxes in the Mobile World with TraceboxAndroid
Thirion, Valentin; Edeline, Korian ULg; Donnet, Benoît ULg

in 7th International Workshop on Traffic Monitoring and Analysis (TMA) (2015, April)

Middleboxes are largely deployed over cellular networks. It is known that they might disrupt network performance, expose users to security issues, and harm protocols deployability. Further, hardly any ... [more ▼]

Middleboxes are largely deployed over cellular networks. It is known that they might disrupt network performance, expose users to security issues, and harm protocols deployability. Further, hardly any network measurements tools for smartphones are able to infer middlebox behaviors, specially if one cannot control both ends of a path. In this paper, we present TraceboxAndroid a proof-of-concept measurement application for Android mobile devices implementing the tracebox algorithm. It aims at diagnosing middlebox-impaired paths by detecting and locating rewriting middleboxes. We analyze a dataset sample to highlight the range of opportunities offered by TraceboxAndroid. We show that TraceboxAndroid can be useful for mobile users as well as for the research community. [less ▲]

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See detailModelling carbon fluxes of forest and grassland ecosystems in Western Europe using the CARAIB dynamic vegetation model: evaluation against eddy covariance data.
Henrot, Alexandra-Jane ULg; François, Louis ULg; Dury, Marie ULg et al

in Geophysical Research Abstracts (2015, April), 17

Eddy covariance measurements are an essential resource to understand how ecosystem carbon fluxes react in response to climate change, and to help to evaluate and validate the performance of land surface ... [more ▼]

Eddy covariance measurements are an essential resource to understand how ecosystem carbon fluxes react in response to climate change, and to help to evaluate and validate the performance of land surface and vegetation models at regional and global scale. In the framework of the MASC project (« Modelling and Assessing Surface Change impacts on Belgian and Western European climate »), vegetation dynamics and carbon fluxes of forest and grassland ecosystems simulated by the CARAIB dynamic vegetation model (Dury et al., iForest - Biogeosciences and Forestry, 4:82-99, 2011) are evaluated and validated by comparison of the model predictions with eddy covariance data. Here carbon fluxes (e.g. net ecosystem exchange (NEE), gross primary productivity (GPP), and ecosystem respiration (RECO)) and evapotranspiration (ET) simulated with the CARAIB model are compared with the fluxes measured at several eddy covariance flux tower sites in Belgium and Western Europe, chosen from the FLUXNET global network (http://fluxnet.ornl.gov/). CARAIB is forced either with surface atmospheric variables derived from the global CRU climatology, or with in situ meteorological data. Several tree (e.g. Pinus sylvestris, Fagus sylvatica, Picea abies) and grass species (e.g. Poaceae, Asteraceae) are simulated, depending on the species encountered on the studied sites. The aim of our work is to assess the model ability to reproduce the daily, seasonal and interannual variablility of carbon fluxes and the carbon dynamics of forest and grassland ecosystems in Belgium and Western Europe. [less ▲]

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See detailDiurnal and seasonal variability of CO2 fluxes over a degraded Woodland under a Sudanian climate in Northern Benin (West Africa)
Ago, Expédit Evariste; Serça, Dominique; Agbossou, Euloge Kossi et al

in Geophysical Research Abstracts (2015, April), 17

Turbulent CO2 exchanges over a degraded woodland were measured during 17 months (from November 2005 to March 2007) by an eddy-covariance system at Nangatchori in the northern part of Benin, West Africa ... [more ▼]

Turbulent CO2 exchanges over a degraded woodland were measured during 17 months (from November 2005 to March 2007) by an eddy-covariance system at Nangatchori in the northern part of Benin, West Africa. The site (Lat 9.65°N, Long 1.74°E, Alt: 432 m), under a Sudanian climate, is one of the sites that were equipped in the framework of the international AMMA-CATH program. The site was highly disturbed during preceding years by illegal tree logging, agricultural activities, cattle pasture, and bushfire. The footprint area is mainly formed by herbs and crops with some sparse shrubs and trees. Fluxes data were completed during the same period by meteorological measurements made at the Nalohou site located approximately 20 km from Nangatchori, and by an inventory of dominating species on 1km2 area around the tower during the wet season. Fluxes response to climatic variables was analyzed. The annual drought and moisture cycle was found to be the main controlling factor of the ecosystem dynamics. A very clear response of CO2 fluxes to PPFD appears, but is different according to seasons. During wet season, CO2 uptake increases with increasing PPFD following a typical curvilinear function and saturates for high PPFD (PPFD > 1000 µmol m-2 s-1), while during dry season, a very weak linear response of CO2 fluxes was observed. No clear dependency of the total ecosystem respiration on temperature was observed. At an annual scale (from November 1st 2005 to October 31st 2006), net carbon sequestered by the ecosystem was 18 +- 5 g C m-2. Finally, with respect to the water use the ecosystem appeared to be more efficient during morning and wet season than during afternoon and dry period. [less ▲]

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See detailFunctional MRI for predicting metastatic spreading at the time of surgery after neoadjuvant radiotherapy
LALLEMAND, François ULg; Leroi, Natacha ULg; Bahri, Mohamed Ali ULg et al

Poster (2015, April)

Neoadjuvant radiotherapy (NeoRT) improves tumor local control and tumor resection in many cancers. The timing between the end of the NeoRT and surgery is driven by the occurrence of side effects or the ... [more ▼]

Neoadjuvant radiotherapy (NeoRT) improves tumor local control and tumor resection in many cancers. The timing between the end of the NeoRT and surgery is driven by the occurrence of side effects or the tumor downsizing. Some studies demonstrated that the timing of surgery and the RT schedule could influence tumor dissemination and subsequently patient overall survival. Our aim is to evaluate with functional MRI the impact of the radiation treatment on the tumor microenvironment and subsequently to determine the best timing to perform surgery for avoiding tumor spreading. [less ▲]

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See detailWolff’s Law and the Interplay between Bone Structure and External Loading
Ruffoni, Davide ULg; Christen, Patrik; Scherf, Heike et al

in IBMS BoneKEy (2015, April), 13

Detailed reference viewed: 20 (7 ULg)
See detailThe Ramses Project in interaction / Metadata and Thesauri in Ramsès / Towards a TEI pivot-format for Ancient Egyptian texts
Polis, Stéphane ULg

Conference (2015, April)

Three talks about forthcoming developments in the field of Ancient Egyptian corpus annotation.

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See detailTowards a Middlebox Policy Taxonomy: Path Impairments
Edeline, Korian ULg; Donnet, Benoît ULg

in International Workshop on Network Science for Communication Networks (NetSciCom): Hong Kong April 27 2015 (2015, April)

Recent years have seen the rise of middleboxes, such as firewalls, NATs, proxies, or Deep Packet Inspectors. Those middleboxes play an important role in today's Internet, including enterprise networks and ... [more ▼]

Recent years have seen the rise of middleboxes, such as firewalls, NATs, proxies, or Deep Packet Inspectors. Those middleboxes play an important role in today's Internet, including enterprise networks and cellular networks. However, despite their huge success in modern network architecture, they have a negative impact on the Internet evolution as they can slow down the TCP protocol evolution and its extensions. Making available a summary of the potential middlebox network interferences is of the highest importance as it could allow researchers to confront their new transport protocol to potential issues caused by middleboxes. And, consequently, allowing again innovation in the Internet. This is exactly what we tackle in this paper. We propose a path impairment oriented middlebox taxonomy that aims at categorizing the initial purpose of a middlebox policy as well as its potential unexpected complications. Based on a measurement campaign on IPv4 and IPv6 networks, we confront our taxonomy to the real world. Our dataset is freely available. [less ▲]

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See detailFacteurs génétiques et risque de dysglycémie dans des familles de diabétiques de type 2: l’étude DESCENDANCE
Franc, S; Cauchi, S; Yengo, L et al

in Diabètes & Métabolism (2015, April), 41(s1), 10-35

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See detailAssessment of damage and anisotropic plasticity models to predict Ti-6Al-4V behavior
Guzmán Inostroza, Carlos Felipe ULg; Tuninetti, Víctor; Gilles, Gaëtan ULg et al

in Key Engineering Materials [=KEM] (2015, April), 651-653

The plastic behavior of the Ti-6Al-4V alloy includes several features as strength differential effect, anisotropy and yield strength sensitivity to temperature and strain rate. Monotonic tensions in the ... [more ▼]

The plastic behavior of the Ti-6Al-4V alloy includes several features as strength differential effect, anisotropy and yield strength sensitivity to temperature and strain rate. Monotonic tensions in the three orthogonal directions of the material are performed to identify the Hill ’48 yield criterion. Monotonic compression and plane strain tensile tests are also included in the experimental campaign to identify the orthotropic yield criterion of CPB06. An assessment of the two models is done by comparing the yield loci and the experimental data points for different levels of plastic work. A first approach of the damage modelling of the Ti-6AL-4V alloy is investigated with an extended Gurson-Tvergaard-Needleman damage model based on Hill ’48 yield criterion. Finite element simulations of the experiments are performed and numerical results allows checking force-displacement curves until rupture and local information like displacement and strain fields. The prediction ability of the Hill ’48, CPB and extended Gurson models are assessed on simple shear and notched tensile tests until fracture. [less ▲]

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See detailRemote control of self-assembled magnetocapillary microswimmers
Grosjean, Galien ULg; Lagubeau, Guillaume ULg; Hubert, Maxime ULg et al

Poster (2015, April)

Physics governing the locomotion of microorganisms and other microsystems is dominated by viscous damping. An effective swimming strategy involves the non-reciprocal and periodic deformations of the ... [more ▼]

Physics governing the locomotion of microorganisms and other microsystems is dominated by viscous damping. An effective swimming strategy involves the non-reciprocal and periodic deformations of the considered body. Herein, we show that a magnetocapillary-driven self-assembly, composed of three soft-ferromagnetic beads, is able to swim along a liquid-air interface when driven by an external magnetic field. Moreover, the system can be fully controled, opening ways to explore low Reynolds number swimming and to create micromanipulators in various applications. [less ▲]

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See detailDecrease of the Black Sea Oxygen Inventory through the second half of the XXth century
capet, arthur; stanev, Emil; Grégoire, Marilaure ULg

Poster (2015, April)

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See detailImproving energy partitioning and the nighttime energy balance by implementation of a multi-layer energy budget in ORCHIDEE-CAN
Chen, Yiying; Ryder, James; Naudts, Kim et al

in Geophysical Research Abstracts (2015, April), 17

Canopy structure is one of the most important vegetation characteristics for land-atmosphere interactions as it determines the energy and scalar exchanges between land surface and overlay air mass. In ... [more ▼]

Canopy structure is one of the most important vegetation characteristics for land-atmosphere interactions as it determines the energy and scalar exchanges between land surface and overlay air mass. In this study we evaluated the performance of a newly developed multi-layer energy budget (Ryder et al., 2014) in a land surface model, ORCHIDEE-CAN (Naudts et al., 2014), which simulates canopy structure and can be coupled to an atmospheric model using an implicit procedure. Furthermore, a vertical discrete drag parametrization scheme was also incorporated into this model, in order to obtain a better description of the sub-canopy wind profile simulation. Site level datasets, including the top-of-the-canopy and sub-canopy observations made available from eight flux observation sites, were collected in order to conduct this evaluation. The geo-location of the collected observation sites crossed climate zones from temperate to boreal and the vegetation types included deciduous, evergreen broad leaved and evergreen needle leaved forest with maximum LAI ranging from 2.1 to 7.0. First, we used long-term top-of-the-canopy measurements to analyze the performance of the current one-layer energy budget in ORCHIDEE-CAN. Three major processes were identified for improvement through the implementation of a multi-layer energy budget: 1) night time radiation balance, 2) energy partitioning during winter and 3) prediction of the ground heat flux. Short-term sub-canopy observations were used to calibrate the parameters in sub-canopy radiation, turbulence and resistances modules with an automatic tuning process following the maximum gradient of the user-defined objective function. The multi-layer model is able to capture the dynamic of sub-canopy turbulence, temperature and energy fluxes with imposed LAI profile and optimized parameter set at a site level calibration. The simulation result shows the improvement both on the nighttime energy balance and energy partitioning during winter and presents a better Taylor skill score, compared to the result from single layer simulation. The importance of using the multi-layer energy budget in a land surface model for coupling to the atmospheric model will also be discussed in this presentation. [less ▲]

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See detailA comparative study of finite strain formulations in the buckling of cruciform columns
Careglio, Claudio; Canales Cardenas, Cristian ULg; Garcia Garino, Carlos et al

Conference (2015, April)

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See detailThe iPot Project: improved potato monitoring in Belgium using remote sensing and crop growth modelling
Piccard, I.; Nackaerts, K.; Gobin, A. et al

Poster (2015, April)

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See detailL’auteur de la Passio sanctae Salsae a-t-il aussi écrit la Passio sancti Fabii ?
Fialon, Sabine ULg

in Meyers, Jean; Fialon, Sabine (Eds.) La Passio sanctae Salsae. Recherches sur une passion tardive d’Afrique du Nord. Avec une nouvelle édition critique d’A. M. Piredda et une traduction annotée du G.R.A.A. (2015, April)

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See detailDoes the soil’s effective hydraulic conductivity adapt in order to obey the Maximum Entropy Production principle? A lab experiment
Westhoff, Martijn ULg; Zehe, Erwin; Erpicum, Sébastien ULg et al

Conference (2015, April)

The Maximum Entropy Production (MEP) principle is a conjecture assuming that a medium is organized in such a way that maximum power is subtracted from a gradient driving a flux (with power being a flux ... [more ▼]

The Maximum Entropy Production (MEP) principle is a conjecture assuming that a medium is organized in such a way that maximum power is subtracted from a gradient driving a flux (with power being a flux times its driving gradient). This maximum power is also known as the Carnot limit. It has already been shown that the atmosphere operates close to this Carnot limit when it comes to heat transport from the Equator to the poles, or vertically, from the surface to the atmospheric boundary layer. To reach this state close to the Carnot limit, the effective thermal conductivity of the atmosphere is adapted by the creation of convection cells (e.g. wind). The aim of this study is to test if the soil’s effective hydraulic conductivity also adapts itself in such a way that it operates close to the Carnot limit. The big difference between atmosphere and soil is the way of adaptation of its resistance. The soil’s hydraulic conductivity is either changed by weathering processes, which is a very slow process, or by creation of preferential flow paths. In this study the latter process is simulated in a lab experiment, where we focus on the preferential flow paths created by piping. Piping is the process of backwards erosion of sand particles subject to a large pressure gradient. Since this is a relatively fast process, it is suitable for being tested in the lab. In the lab setup a horizontal sand bed connects two reservoirs that both drain freely at a level high enough to keep the sand bed always saturated. By adding water to only one reservoir, a horizontal pressure gradient is maintained. If the flow resistance is small, a large gradient develops, leading to the effect of piping. When pipes are being formed, the effective flow resistance decreases; the flow through the sand bed increases and the pressure gradient decreases. At a certain point, the flow velocity is small enough to stop the pipes from growing any further. In this steady state, the effective flow resistance of the sand bed will be compared with the theoretical optimal flow resistance obtained with the MEP principle. For this study, different magnitudes of the forcing will be tested, while also the effect of dry spells will be explored. [less ▲]

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See detailTillage as a tool to manage crop residue : impact on sugar beet production
Hiel, Marie-Pierre ULg; Degrune, Florine ULg; Parvin, Nargish ULg et al

Poster (2015, April)

Crop residues and plant cover represent a pool of organic matter that can be used either to restore organic matter in soils, and therefore maintain soil fertility, or that can be valorized outside of the ... [more ▼]

Crop residues and plant cover represent a pool of organic matter that can be used either to restore organic matter in soils, and therefore maintain soil fertility, or that can be valorized outside of the field (e.g. energy production). However, it is crucial that the exportation of residues is not done to the detriment of the system sustainability. Three long term experiments have been settled in the loamy region in Belgium. All of them are designed to study the effect of residues management by several tillage systems (conventional plowing versus reduced tillage) on the whole soil-water-plant system. SOLRESIDUS is a field experiment where we study the impact of crop residue management while in SOLCOUVERT and SOLCOUVERT-BIS, we study the impact of cover crop management. SOLRESIDUS was started in 2008. In this field, four contrasted crop residues managements are tested in order to contrast as much as possible the responses from the soil-water plant system. Two practices characterize the four modalities: soil tillage (ploughing at 25 cm depth or reduce tillage at 10 cm max) and residue management (exportation or restitution). SOLCOUVERT and SOLCOUVERT-BIS were started in 2012 and 2013 respectively. In those fields cover crop management is also diverse: destruction of the cover crop by winter ploughing, spring ploughing, strip tillage (with a chemical destruction if needed) or shallow tillage (with a decompaction before cover crop sowing). Although although the overall project aims at studying the impact of management on the whole soil-water-plant system, here we will only present the results concerning crop production (sugar beet) in SOLCOUVERT experiments. The presented data will include germination rate, crop development (biomass quantification and BBCH stages) weeds population, disease occurrence, pest occurrences, nitrogen uptake by plants, quality and quantity of harvested products.   [less ▲]

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See detailLe dossier papyrologique de Favorinos d'Arles
Marganne, Marie-Hélène ULg

in Amato, Eugenio; Marganne, Marie-Hélène (Eds.) Le traité Sur l'exil de Favorinos d'Arles. Papyrologie, philologie et littérature (2015, April)

La mise en série et la comparaison des trois papyrus littéraires grecs en relation avec Favorinos révèlent maints points communs : même datation au IIIe siècle, même utilisation d'un support d'écriture de ... [more ▼]

La mise en série et la comparaison des trois papyrus littéraires grecs en relation avec Favorinos révèlent maints points communs : même datation au IIIe siècle, même utilisation d'un support d'écriture de réemploi, même type d'écriture, informelle ou cursive, et même contexte de production ou d'utilisation. Provenant, l’un, de la Marmarique, et un autre, sûrement, d'Oxyrhynchus, ils attestent la connaissance de l'auteur arlésien (c. 80-150/160), dans la chôra égyptienne au sens large, moins d'un siècle après sa mort, probablement dans le cadre particulier des intérêts liés à la rhétorique et à son enseignement ou son apprentissage ou sa pratique. [less ▲]

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See detailSoil microbial community composition changes according to the tillage practice and plant development stage
Degrune, Florine ULg; Dufrêne, Marc ULg; Taminiau, Bernard ULg et al

Poster (2015, April)

Agricultural practices have a strong impact on soil bacterial and fungal community composition. Furthermore, microbial community composition can change with the stage of plant development. We are ... [more ▼]

Agricultural practices have a strong impact on soil bacterial and fungal community composition. Furthermore, microbial community composition can change with the stage of plant development. We are interested in exploring these effects in relation to changes induced by agriculture (conventional and reduced tillage) and plant stage (germination and flowering) in soil conditions. Here, instead of examining this impact at a high taxonomic level such as phylum and/or class, thus missing potentially relevant information from lower levels, we propose an original method: exploiting the available sequence information at the lowest taxonomic level attainable for each operational taxonomic unit. Results show that some microbial communities were impacted only by the tillage practice , while others were impacted only by the stage of plant. Changes in microbial community composition could be due to the soil conditions induced by the soil practice and the stage of plant. [less ▲]

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See detailBiogenic Volatile Organic Compound (BVOC) emissions from agricultural crop species: is guttation a possible source for methanol emissions following light/dark transition?
Mozaffar, Ahsan ULg; Amelynck, Crist; Bachy, Aurélie ULg et al

in Geophysical Research Abstracts (2015, April), 17(EGU2015-2110-1),

In the framework of the CROSTVOC (CROp STress VOC) project, the exchange of biogenic volatile organic compounds (BVOCs) between two important agricultural crop species, maize and winter wheat, and the ... [more ▼]

In the framework of the CROSTVOC (CROp STress VOC) project, the exchange of biogenic volatile organic compounds (BVOCs) between two important agricultural crop species, maize and winter wheat, and the atmosphere has recently been measured during an entire growing season by using the eddy covariance technique. Because of the co-variation of BVOC emission drivers in field conditions, laboratory studies were initiated in an environmental chamber in order to disentangle the responses of the emissions to variations of the individual environmental parameters (such as PPFD and temperature) and to diverse abiotic stress factors. Young plants were enclosed in transparent all-Teflon dynamic enclosures (cuvettes) through which BVOC-free and RH-controlled air was sent. BVOC enriched air was subsequently sampled from the plant cuvettes and an empty cuvette (background) and analyzed for BVOCs in a high sensitivity Proton-Transfer Reaction Mass Spectrometer (hs-PTR-MS) and for CO2 in a LI-7000 non-dispersive IR gas analyzer. Emissions were monitored at constant temperature (25 °C) and at a stepwise varying PPFD pattern (0-650 µmol m-2 s-1). For maize plants, sudden light/dark transitions at the end of the photoperiod were accompanied by prompt and considerable increases in methanol (m/z 33) and water vapor (m/z 39) emissions. Moreover, guttation droplets appeared on the sides and the tips of the leaves within a few minutes after light/dark transition. Therefore the assumption has been raised that methanol is also coming out with guttation fluid from the leaves. Consequently, guttation fluid was collected from young maize and wheat plants, injected in an empty enclosure and sampled by PTR-MS. Methanol and a large number of other compounds were observed from guttation fluid. Recent studies have shown that guttation from agricultural crops frequently occurs in field conditions. Further research is required to find out the source strength of methanol emissions by this guttation phenomenon in real environmental conditions. [less ▲]

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See detailSeed and pollen dispersal in Guineo-Congolian canopy tree species – insights from genetic markers in multiple species
Hardy, Olivier J.; Duminil, Jérôme; Daïnou, Kasso ULg et al

Conference (2015, April)

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See detailMeasuring and modelling the intra-day variability of the CO2 & CO2 vertical soil profile production in a Scots pine forest
Longdoz, Bernard; Goffin, Stéphanie; Parent, Florian et al

in Geophysical Research Abstracts (2015, April), 17

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See detailThe CROSTVOC project – an integrated approach to study the effect of stress on BVOC exchange between agricultural crops and grassland ecosystems and the atmosphere
Amelynck, Crist; Heinesch, Bernard ULg; Aubinet, Marc ULg et al

in Geophysical Research Abstracts (2015, April), 17

Global changes in atmospheric composition and climate are expected to affect BVOC exchange between terrestrial vegetation and the atmosphere through changes in the drivers of constitutive BVOC emissions ... [more ▼]

Global changes in atmospheric composition and climate are expected to affect BVOC exchange between terrestrial vegetation and the atmosphere through changes in the drivers of constitutive BVOC emissions and by increases in frequency and intensity of biotic or abiotic stress episodes. Indeed, several studies indicate changes in the emission patterns of constitutive BVOCs and emission of stress-induced BVOCs following heat, drought and oxidative stress, amongst others. Relating changes in BVOC emissions to the occurrence of one or multiple stressors in natural environmental conditions is not straightforward and only few field studies have dealt with it, especially for agricultural crop and grassland ecosystems. The CROSTVOC project aims to contribute in filling this knowledge gap in three ways. Firstly, it aims at performing long-term BVOC emission field measurements from maize (Zea mays L.) and wheat (Triticum aestivum L.), two important crop species on the global scale, and from grassland. This should lead to a better characterization of (mainly oxygenated) BVOC emissions from these understudied ecosystems, allowing a better representation of those emissions in air quality and atmospheric chemistry and transport models. BVOC fluxes are obtained by the Disjunct Eddy Covariance by mass scanning (DEC-MS) technique, using a hs-PTR-MS instrument for BVOC analysis. Secondly, the eddy covariance BVOC flux measurements (especially at the grassland site) will be accompanied by ozone flux, chlorophyll fluorescence, photosynthesis and soil moisture measurements, amongst others, to allow linking alterations in BVOC emissions to stress episodes. Simultaneously, automated dynamic enclosures will be deployed in order to detect specific abiotic and biotic stress markers by PTR-MS and identify them unambiguously by GC-MS. Thirdly, the field measurements will be accompanied by laboratory BVOC flux measurements in an environmental chamber in order to better disentangle the responses of the BVOC emissions to driving factors that co-occur in field conditions and to determine the influence of single abiotic stressors on BVOC emissions. Next to a general presentation, some preliminary results of the project will be shown. [less ▲]

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See detailSeismic hazard assessment of the Kivu rift segment based on a new sismo-tectonic zonation model (Western Branch of the East African Rift system)
Havenith, Hans-Balder ULg; Delvaux, Damien

in EGU General Assembly Conference Abstracts (2015, April)

In the frame of the Belgian GeoRisCA multi-risk assessment project focused on the Kivu and Northern Tanganyika Region, a seismic hazard map has been produced for this area. It is based on a on a recently ... [more ▼]

In the frame of the Belgian GeoRisCA multi-risk assessment project focused on the Kivu and Northern Tanganyika Region, a seismic hazard map has been produced for this area. It is based on a on a recently re-compiled catalogue using various local and global earthquake catalogues. The use of macroseismic epicenters determined from felt earthquakes allowed to extend the time-range back to the beginning of the 20th century, thus spanning about 100 years. The magnitudes have been homogenized to Mw and the coherence of the catalogue has been checked and validated. The seismo-tectonic zonation includes 10 seismic source areas that have been defined on the basis of the regional geological structure, neotectonic fault systems, basin architecture and distribution of earthquake epicenters... [less ▲]

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See detailTesting the impact of stratigraphic uncertainty on spectral analysis of sedimentary time series
Martinez, Mathieu; Kotov, Sergey; De Vleeschouwer, David et al

Poster (2015, April)

Spectral analysis has become a key tool for identifying the imprint of astronomical forcing on sedimentary records. In a next step, the identified cycles often contribute to the construction of a precise ... [more ▼]

Spectral analysis has become a key tool for identifying the imprint of astronomical forcing on sedimentary records. In a next step, the identified cycles often contribute to the construction of a precise Geological Time Scale and to an in-depth understanding of past climate changes. Most of spectral analyses (Fast Fourier Transforms, the Multi-Taper Method. . . ) require a constant sample step. Unfortunately, an equally spaced geological data series is, in practice, nearly impossible to obtain from field sedimentary series. Usually, there is a 10% uncertainty on the field measurements of the stratigraphic thickness within sedimentary series. Hence, important uncertainties exist on the actual position of each sample. Another source of uncertainty are errors in a time-space model. In this study, we explore the impact that the stratigraphic uncertainty on the sample position has on the result of spectral analyses. To simulate this uncertainty, we developed a model based on the Monte Carlo randomisation of the distance between each successive point. In this way, the stratigraphic order of the data points is not affected after imp lementating this model. The application of this model to a theoretical sinusoid series and to several real sedimentary series shows that uncertainties in the actual position of samples can highly reduce the spectral powers of the frequencies ranging from the Nyquist Frequency up to 1/10 of the Nyquist Frequency. We the demonstrate that the precise reconstruction of the Milankovitch cycles in the sedimentary record requires a higher sampling density than previously suggested with, at least, 10 samples per thinnest cycle to be detected, i.e. 10 samples per precession cycle [less ▲]

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See detailThe Fish Migrate and so Must We': the Relationship between International and Internal Environmental Mobility in a Senegalese Fishing Community
Zickgraf, Caroline ULg

Conference (2015, April)

In 2008, the UN designated Saint-Louis “the city most threatened by rising sea levels in the whole of Africa”. The people of Guet Ndar, a densely populated fishing quarter, are coping with environmental ... [more ▼]

In 2008, the UN designated Saint-Louis “the city most threatened by rising sea levels in the whole of Africa”. The people of Guet Ndar, a densely populated fishing quarter, are coping with environmental challenges on two fronts: 1) coastal erosion and intensifying storms have destroyed sea-front homes, and, 2) overfishing and climate change’s maritime impacts are making local fishing less feasible as a livelihood strategy. Based on a local case study, this paper examines Guet Ndarian migration as an adaptive response to environmental risks and more specifically climate change: 1) through the intensification of fishing migration to Mauritania, and 2) through home construction on the mainland away from the encroaching sea. Although these population movements respond to different environmental challenges, this paper identifies their enmeshment as the former facilitates the latter. Furthermore, it embeds these migratory dynamics in their socio-economic context and applies mobility and transnational paradigms to environmentally vulnerable areas. [less ▲]

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See detailIndividual variation of gait characteristics along a 500 meter walk in people with multiple sclerosis and healthy volunteers
Phan-Ba, Rémy; Pierard, Sébastien ULg; Giet, Amaury et al

in Multiple Sclerosis Journal (2015, April), 21(4), 532-533

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See detailLa réception du livre italien dans les anciens Pays-Bas à la première modernité : Bilan et perspectives de recherches
Adam, Renaud ULg

Conference (2015, March 28)

Cette communication sera l’occasion pour Renaud Adam de faire un premier bilan des activités menées en Belgique sur la réception du livre italien dans les anciens Pays-Bas aux XVIe et XVIIe siècles depuis ... [more ▼]

Cette communication sera l’occasion pour Renaud Adam de faire un premier bilan des activités menées en Belgique sur la réception du livre italien dans les anciens Pays-Bas aux XVIe et XVIIe siècles depuis le lancement, en novembre 2013, du projet international sur l'Édition italienne dans l'espace francophone à la première modernité (EDITEF). Il présentera notamment les premiers résultats d’une enquête centrée sur la place du livre italien, en langue vulgaire ou en traduction, dans la partie d’expression française des anciens Pays- [less ▲]

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See detailLe retour du sujet en didactique des langues ?
Defays, Jean-Marc ULg

Conference (2015, March 28)

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See detailOrgan donation after euthanasia on specific patients' request in Belgium
Ysebaert, Y; DETRY, Olivier ULg; Mikhalski, D et al

Conference (2015, March 28)

Euthanasia is banned in almost countries of the world, although in 2002 Belgium legalized it for adults under strict conditions (in a similar way after The Netherlands in 2001. The patient must be in a ... [more ▼]

Euthanasia is banned in almost countries of the world, although in 2002 Belgium legalized it for adults under strict conditions (in a similar way after The Netherlands in 2001. The patient must be in a medically futile condition, of constant and unbearable physical or mental suffering that cannot be alleviated, resulting from a serious and incurable disorder caused by illness or accident. If the person is not in the terminal phase of his illness, the 2 doctors must consult with a third doctor, either a psychiatrist or a specialist in the disease concerned. From 2005 till 2014 more than 25 patients, suffering from diverse neuropsychiatric diseases, got their request for euthanasia granted, and subsequently asked spontaneously for the possibility of organ donation. The involved physicians, the transplant teams and the Institutional Ethics Committees, had the well-discussed opinion that this strong request for organ donation after euthanasia could not be denied. A clear separation between the euthanasia request, the euthanasia procedure and the organ procurement procedure was judged necessary. After extensive preparation, finally, in Belgium, 17 patients got their wish for organ donation after euthanasia fulfilled, in several academic or non-academic hospitals and in different regions : Antwerpen 6, Leuven 5, Liege 2, Namur 1, Turnhout 1, and Brussels 2. Several requests and negotiations were started for other patients but ultimately failed due to patients’ personal choices (e.g. patient wanted finally to die at home) or logistically reasons (e.g. who would fulfil the euthanasia in case all involving doctors were not employed or connected to a hospital). The euthanasia procedure was carried out by three physicians in the neighborhood of the operating room. After clinical diagnosis of cardiac death, the procurement team came in and performed the organ procurement similar as in a DCD type III procedure. The liver, two kidneys and sometimes lungs and pancreatic islets could be successfully recovered and transplanted, after organ allocation via Eurotransplant. Transplant centers were informed about the nature of the case and the elements of organ procurement. There was primary function of all organs. The possibility of organ donation after their euthanasia provides a very much improved self-image of these patients, and adds something really positive to the euthanasia procedure, and is very well appreciated by the requesting patients, relatives, patient and professional organisations and public media. Some practical and ethical issues still have to be discussed to allow expansion of this possibility of organ donation. [less ▲]

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See detailLa promotion de l’activité physique dans les écoles : un projet de société
Cloes, Marc ULg

Conference (2015, March 28)

A l'heure actuelle, les preuves scientifiques existent pour souligner la nécessité de lutter contre la sédentarité. L'école constitue un pilier essentiel de l'action à mettre en oeuvre dans cette ... [more ▼]

A l'heure actuelle, les preuves scientifiques existent pour souligner la nécessité de lutter contre la sédentarité. L'école constitue un pilier essentiel de l'action à mettre en oeuvre dans cette perspective et, en son sein, les enseignants en éducation physique devraient jouer un rôle central en tant que 'pierre angulaire' de la promotion de l'activité physique. Ceci exige toutefois un recentrage de leur intervention sur le développement de citoyens physiquement éduqués, justifiant un changement dans les priorités de leur enseignement. Cela ne peut toutefois pas être mis en oeuvre sans le soutien des autorités scolaires locales et du domaine de la santé. Un axe de travail consiste finalement à éduquer la société en communiquant davantage à propos de ce qui est fait à l'école pour développer un style de vie actif. [less ▲]

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See detailInfusion of third-party mesenchymal stromal cells after liver transplantation: a phase 1, open-label, clinical study
DETRY, Olivier ULg; VANDERMEULEN, Morgan ULg; DELBOUILLE, Marie-Hélène ULg et al

Poster (2015, March 27)

Transplanted patients have to deal with numerous side effects of life-long dependence on immunosuppressive drugs. Paradoxically these drugs fail to prevent acute and/or chronic rejection in many cases ... [more ▼]

Transplanted patients have to deal with numerous side effects of life-long dependence on immunosuppressive drugs. Paradoxically these drugs fail to prevent acute and/or chronic rejection in many cases. Mesenchymal stromal cells (MSC) are multipotent and self-renewing bone marrow progenitors that have been shown both in vitro and in vivo as capable of (i) immunomodulation, (ii) anti-inflammation in case of ischemia/reperfusion injury, and (ii) stimulation of tissue repair. MSC could therefore be very interesting in organ recipients to limit chronic graft damage and to allow tolerance. This study aimed to be the first clinical evaluation of the safety and tolerability of MSC infusion after liver transplantation in a prospective, controlled, phase I study. Clinical grade MSCs were locally collected from the bone marrow of unrelated healthy donors. They were cultured in a GMP-compliant lab, underwent extensive quality controls and were frozen for storage in a MSC bank. When needed for patient treatment, MSC were thawed and intravenously injected into patients. 10 liver transplant recipients under standard immunosuppression (TAC-MMF-low dose steroids until day 30) received 1.5-3x106/kg MSC on post- operative day 3 ± 2. These patients were prospectively compared to a group of 10 control (MSC-) liver recipients. Primary endpoints were MSC infusion toxicity, and incidence of cancer and opportunistic infections at month 6. Secondary endpoints were patient and graft survivals and rejection at month 6, as well as the effects of MSC on recipients’ immune function and on immunohistology of at month 6 graft biopsies. No MSC infusional toxicity was observed. Both groups were comparable in terms of donor and recipient characteristics. There was no difference in primary end-points between control and MSC groups. No patient developed de novo cancer. There was no statistical difference in patient and graft survivals or in rejection rates. There was no graft rejection in the MSC group. Month-6 graft biopsies were not different according to Banff and fibrosis scores. This phase I study showed excellent tolerability and safety of a single infusion of third-party MSC after liver transplantation. There were no graft safety issues and no excess of immunosuppression after MSC injection. Further analyses of consequences of MSC injection on the immune profile are needed. The possibility of avoiding calcineurin-inhibitors with repeated MSC injections as main immunosuppressive therapy and/of tolerance induction by MSC infusion should be investigated by further studies. [less ▲]

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See detailLa collaboration entre différentes disciplines médicales : ou est le problème ? Etude Partnership in Medicine
Vanmeerbeek, Marc ULg; Govers, Patrick ULg; Schippers, Nathalie ULg et al

Conference (2015, March 27)

Objectifs Les maladies ou problèmes médicaux d’origine professionnelle, ou en lien avec le travail, impliquent à des degrés divers les médecins généralistes (MG), les médecins du travail (MT) et les ... [more ▼]

Objectifs Les maladies ou problèmes médicaux d’origine professionnelle, ou en lien avec le travail, impliquent à des degrés divers les médecins généralistes (MG), les médecins du travail (MT) et les médecins-conseils des mutuelles (MC). Le manque de relation fonctionnelle entre eux peut compliquer ou retarder le retour au travail du patient. L’étude cherchait des pistes d’amélioration de la collaboration. Méthode Deux méthodes de consensus ont été successivement utilisées parmi les trois professions : huit groupes nominaux (GN) ont réunis 74 médecins de terrain; deux rondes Delphi ont concerné 28 décideurs. Résultats Un seul médecin a été perdu de vue entre les 2 tours du Delphi. Les propositions issues des GN concernaient le transfert d’informations (surtout les MT et les MC), la collaboration (surtout les MG et les MT), les connaissances, et le cadre légal et réglementaire (surtout les MC). Cinq questions sur 14 n’ont pas fait consensus (≥75%) au 1er tour du Delphi, et 10 propositions sur 13 ont été rejetées au 2e tour. Les désaccords portaient sur la nature des données à transférer, les modalités de transfert d’information, la disponibilité des données de contact des médecins. Un processus d’évitement spécifique a été mis en évidence. Certains commentaires montraient un déni de la capacité des autres à comprendre son champ professionnel, et une difficulté à considérer leur spécificité propre. Conclusions L’étude montre que le patient n’est pas un objet partagé de la relation. Le modèle Resource Dependence Institutional Cooperation (De Rijk) permet de distinguer les entraves à la volonté de coopérer (dépendance perçue) des limitations dans la capacité à le faire (manque de ressources). Le modèle quadridimensionnel de la collaboration (D’Amour) identifie un déficit d’internalisation du côté relationnel (reconnaissance des autres), et un déficit de gouvernance et de formalisation du côté organisationnel, où des initiatives volontaristes des autorités seraient bienvenues. [less ▲]

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See detailHenri Lévy-Bruhl et Fernand De Visscher, une amitié Franco-Belge
Gerkens, Jean-François ULg

Conference (2015, March 27)

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See detailApplications of stable isotopes in environmental studies at the University of Liege
Sturaro, Nicolas ULg; Borges, Alberto ULg; Das, Krishna ULg et al

Poster (2015, March 26)

Measurement and use of stable isotope ratios have a long history at the University of Liege (Belgium). Since at least 30 years, applications of stable isotopes in marine ecosystems have been developed ... [more ▼]

Measurement and use of stable isotope ratios have a long history at the University of Liege (Belgium). Since at least 30 years, applications of stable isotopes in marine ecosystems have been developed within the Laboratory of Oceanology and, more recently, within the Chemical Oceanography Unit. In the Laboratory of Oceanology, one research axis is the measurement of stable isotope composition (C, N, S) in organic matter to delineate trophic web structure and to study animal diet, their trophic niches and their alteration by human activities. This methodology has been successively applied worldwide in different habitats and ecosystems (marine, freshwater, terrestrial) in temperate and tropical areas. Mediterranean food web and fish trophic ecology have received a particular attention. Coupling between trophic ecology and ecotoxicology is another area of investigation. This has been applied mainly to marine vertebrates and freshwater ecosystems. Stable isotope labelling is also used in our laboratory to study and quantify various ecological processes such as inorganic nitrogen incorporation and trophic transfers. The laboratory facilities, renewed in 2012 and managed by Dr. Gilles Lepoint, are composed of an elemental analyser (EA, vario MICRO cube, Elementar) and a gas chromatography (GC, Agilent) coupled to an isotope ratio mass spectrometer (IRMS, Isoprime 100). The GC is also equipped with a quadrupole mass spectrometer. In 2014, the Chemical Oceanography Unit, headed by Dr. Alberto Borges, has acquired and implemented an off-axis cavity ring-down spectroscopy (CRDS) for the measurements of δ15Nα, δ15Nβ, δ18O of N2O. This enables characterization of the N2O origin in a variety of aquatic environments including groundwater in Wallonia, rivers and lakes in Wallonia and Africa, coastal environments (Scheldt estuary, Lake Grevelingen, North Sea), Mediterranean seagrass beds, and Antarctic and Arctic sea-ice. [less ▲]

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See detailDigitizing Artists’ Identity and Networks: EpistolART, a New Database
Delfosse, Annick ULg

Conference (2015, March 26)

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