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See detailIntroduction à l'histoire et aux théories de la restauration
Verbeeck, Muriel ULg

Scientific conference (2016, April 18)

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See detailCanopy proximity estimation and impact on long term turbulent fluxes above a heterogeneous forest
Hurdebise, Quentin ULg; Vincke, Caroline; De Ligne, Anne ULg et al

Poster (2016, April 18)

With the development of eddy covariance networks like Fluxnet, ICOS or NEON, long-term data series of carbon dioxide, water vapor and other gas exchanges between terrestrial ecosystems and atmosphere will ... [more ▼]

With the development of eddy covariance networks like Fluxnet, ICOS or NEON, long-term data series of carbon dioxide, water vapor and other gas exchanges between terrestrial ecosystems and atmosphere will become more and more numerous. However, long-term analyses of such exchanges require a good understanding of measurement conditions during the investigated period. Independently of climate drivers, measurements may indeed be influenced by measurement conditions themselves subjected to long-term variability due to vegetation growth or set-up changes. The present research refers to the Vielsalm Terrestrial Observatory (VTO) where fluxes of momentum, carbon dioxide, latent and sensible heat have been continuously measured by eddy covariance during twenty years. VTO is an ICOS site installed in a mixed forest (beech, silver fir, Douglas fir, Norway spruce) in the Belgian Ardennes. A multidisciplinary approach was developed in order to investigate the spatial and temporal evolution of several site characteristics: - displacement height (d) and relative measurement height (z-d) were determined using a spectral approach that compared observed and theoretical cospectra; - turbulence statistics were analyzed in the context of Monin-Obukhov similarity theory; - tree height during the measurement period was obtained by combining tree height inventories, a LIDAR survey and tree growth models; - measurement footprint was determined by using a footprint model. A good agreement was found between the three first approaches. Results show notably that z-d was subjected to both temporal and spatial evolution. Temporal evolution resulted from continuous tree growth as well as from a tower raise, achieved in 2009. Spatial evolution, due to canopy heterogeneity, was also observed. The impacts of these changes on measurements are investigated. In particular, it was shown that they affect measurement footprint, flux spectral corrections and flux quality. All these effects must be taken into consideration in order to disentangle long-term flux evolutions due to climate or phenology from changes resulting from measurement set-up changes. [less ▲]

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See detailAre BVOC exchanges in agricultural ecosystems overestimated? Insights from fluxes measured in a maize field over a whole growing season
Bachy, Aurélie ULg; Aubinet, Marc ULg; Schoon, Niels et al

Conference (2016, April 18)

This oral communication aims to present the main outputs of the BVOC (Biogenic Volatile Organic Compounds) flux measurement campaign performed on a maize field in Belgium. It begins by highligthing the ... [more ▼]

This oral communication aims to present the main outputs of the BVOC (Biogenic Volatile Organic Compounds) flux measurement campaign performed on a maize field in Belgium. It begins by highligthing the interest of investigating BVOC exchanges on maize; then measurement techniques are briefly presented. The second half of the communication aims to present and discuss the main outputs of this measurement campaign (similar BVOC composition, lower exchange rate than other maize and cropland/grassland studies, significant importance of soil in ecosystem exchanges, strong differences between exchanges rates observed in this study and those used by up-scaling models). [less ▲]

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See detailPelvic anatomy, a constructive approach
Bonnet, Pierre ULg

Scientific conference (2016, April 18)

Presentation of the pelvis anatomy with live drawing: from bones to viscera

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See detailPisa expliqué à tous : que faire pour améliorer notre enseignement en FWB?
Lafontaine, Dominique ULg

Scientific conference (2016, April 18)

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See detailInter-system biases estimation in multi-GNSS relative positioning with GPS and Galileo
Deprez, Cécile ULg; Warnant, René ULg

Conference (2016, April 18)

The recent increase in the number of Global Navigation Satellite Systems (GNSS) opens new perspectives in the field of high precision positioning. Particularly, the European Galileo program has ... [more ▼]

The recent increase in the number of Global Navigation Satellite Systems (GNSS) opens new perspectives in the field of high precision positioning. Particularly, the European Galileo program has experienced major progress in 2015 with the launch of 6 satellites belonging to the new Full Operational Capability (FOC) generation. Associated with the ongoing GPS modernization, many more frequencies and satellites are now available. Therefore, multi-GNSS relative positioning based on GPS and Galileo overlapping frequencies should entail better accuracy and reliability in position estimations. However, the differences between satellite systems induce inter-system biases (ISBs) inside the multi-GNSS equations of observation. Once these biases estimated and removed from the model, a solution involving a unique pivot satellite for the two considered constellations can be obtained. Such an approach implies that the addition of even one single Galileo satellite to the GPS-only model will strengthen it. The combined use of L1 and L5 from GPS with E1 and E5a from Galileo in zero baseline double differences (ZB DD) based on a unique pivot satellite is employed to resolve ISBs. This model removes all the satelliteand receiver-dependant error sources by differentiating and the zero baseline configuration allows atmospheric and multipath effects elimination. An analysis of the long-term stability of ISBs is conducted on various pairs of receivers over large time spans. The possible influence of temperature variations inside the receivers over ISB values is also investigated. Our study is based on the 5 multi-GNSS receivers (2 Septentrio PolaRx4, 1 Septentrio PolaRxS and 2 Trimble NetR9) installed on the roof of our building in Liege. The estimated ISBs are then used as corrections in the multi-GNSS observation model and the resulting accuracy of multi-GNSS positioning is compared to GPS and Galileo standalone solutions. [less ▲]

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See detailSelection of wavelengths for the quantification of nitrogen concentration in winter wheat by multispectral vision
Marlier, Guillaume ULg; Leemans, Vincent ULg; Destain, Marie-France ULg et al

Poster (2016, April 18)

Hand-held sensors (SPAD meter, N-Tester, …) are used for detecting the leaves nitrogen concentration (Nc) on basis of an optical detection of the chlorophyll concentration. These devices are active ... [more ▼]

Hand-held sensors (SPAD meter, N-Tester, …) are used for detecting the leaves nitrogen concentration (Nc) on basis of an optical detection of the chlorophyll concentration. These devices are active sensors: an internal radiation source emits light and transmission through a leaf is measured in the red (650 nm) and in the near-infrared (920 nm) spectral regions. These devices present several drawbacks. The nitrogen concentration is gained by an indirect way through the chlorophyll concentration and the leaves have to be fixed in a defined position for the measurements. These drawbacks could be overcome by an imaging device that measures the canopy reflectance. Hence, the objective of the paper is to analyse the potential of multispectral imaging for detecting nitrogen concentration. The tests were carried out on parcels submitted to nitrogen inputs varying from 0 to 180 kg N.ha-1. Reference Nc measurements were obtained by the Kjeldahl method and a Hydro N-Tester (Yara). The developed imaging system comprised a CMos camera and a set of 22 interference filters ranging from 450 to 950 nm mounted on a wheel steered by a stepper motor. The image acquisition and the motor rotation were controlled by a program written in C++. The crop was imaged vertically at one meter height. The raw images presented 1280*1024 pixels covering an area approximately 0.5*0.4 m and were recorded with a 12 bits luminance resolution. To deal with the natural irradiance variability of the scene, a white reference was used and the integration time was automatically adjusted for each image. The image treatment included the segmentation of Photosynthetically Active Leaves (PAL) by using Bayes theorem and the computation of the mean PAL reflectance after correction of background and illumination fluctuations. Nc was estimated on basis of the 22 filters by Partial Least Square (PLS) method and by four filters selected by Best Subset Selection (BSS). In comparison with the Kjeldahl method, the estimation of Nc by the Hydro N-Tester, the PLS and the BSS (filters 600-80, 950-100, 650-40 and 450-80 nm) gave determination coefficient and standard error respectively equal to of 0.53, 0.29 %; 0.67, 0.21%; 0.56 and 0.25%. This indicated that the full multi-spectral approach gave significantly better Nc estimation than a portable device and suggested that a camera equipped with four filters would give similar results. [less ▲]

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See detailPISA expliqué à tous : que faire pour améliorer notre enseignement en Belgique francophone ?
Lafontaine, Dominique ULg

Conference given outside the academic context (2016)

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See detailEmilio Salgari e l’avventura
Curreri, Luciano ULg

Scientific conference (2016, April 18)

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See detailPrésentation de "Vivre dans la peur" d'Akira Kurosawa
Tomasovic, Dick ULg

Conference given outside the academic context (2016)

Présentation du contexte de création et de production du film de Kurosawa "Vivre dans la peur" (1955) et analyse stylistique de l'oeuvre.

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See detailReactive gases in the chemistry climate model ECHAM6-HAMMOZ
Schultz, Martin; Franco, Bruno ULg; Kaffashzadeh, Najmeh et al

Poster (2016, April 18)

The recently developed global chemistry climate model ECHAM6-HAMMOZ contains comprehensive and detailed schemes for tropospheric aerosol (HAM) and reactive gases chemistry (MOZ). The Jülich Atmospheric ... [more ▼]

The recently developed global chemistry climate model ECHAM6-HAMMOZ contains comprehensive and detailed schemes for tropospheric aerosol (HAM) and reactive gases chemistry (MOZ). The Jülich Atmospheric (chemical) Mechanism (JAM002) consists of more than 300 species and 650 reactions, including relatively detailed degradation pathways for various volatile organic compounds in the troposphere and stratosphere. State-of-the-art parameterisations for chemical and physical processes are included. Here we present evaluation results from a multi-year simulation of the present-day atmospheric composition. [less ▲]

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See detailChemical and mineralogical proxies of erosion episodes in the dried lake sediments (Amik Lake, Southern Turkey): paleoenvironmental implications
El Ouahabi, Meriam ULg; Hubert, Aurelia ULg; Lebeau, Héléne et al

Poster (2016, April 17)

The Amik Basin in the Eastern Mediterranean region has been continuously occupied since 6000-7000 BC. The landscape has sustained with highly variable anthropic pressure culminating during the Late Roman ... [more ▼]

The Amik Basin in the Eastern Mediterranean region has been continuously occupied since 6000-7000 BC. The landscape has sustained with highly variable anthropic pressure culminating during the Late Roman Period when the Antioch city reached its golden age. The basin also sustained a high seismic activity (M≥7) as it is a releasing step-over along the Dead Sea Fault. The study focuses on the sedimentary record of the Amik Lake occupying the central part of the Basin. Our objective is to constrain major paleo-environmental changes in the area over the last 4000 years and to unravel possible human impacts on the sedimentation. A diverse array of complementary methods was applied on the 6 m long record. High resolution of mineralogical (XRD) and geochemical (XRF) analyses were performed. Quantitative mineralogical phases of sediments by the Rietveld method were computed using Topaz software. The age of the record is constrained combining radionuclide and radiocarbon dating, and checked using the correlation between the earthquake history and rapidly deposited layer identified. A high sedimentation rate of 0.12 cm/yr was inferred at the coring site. The 4000 years old record shows that significant fluctuations of the lake level and the riverine system inflow into the Amik Lake occurred. The Late Bronze lowstand leaded to punctual dryings of the lake at the end of the Bronze/Iron transition marked by the collapse of the Hittite Empire and during the Dark ages. At that time, the riverine was carrying a large terrigenous input linked to strong soil erosion related to deforestation, exploitation of mineral resources and the beginning of upland cultivation. During the Roman Period and in the later periods, upland soils were partly depleted and the riverine system completely transformed by channelization that leaded to a mashification of the Amik Basin. Chemical and mineralogical composition of sediments is quite diversified reflecting the significant geological variation of drainage basins. Abundant calcareous minerals, especially calcite, aragonite, dolomite and small amount of wollastonite characterize the different sedimentary levels recorded in the lake. Levels relatively rich in fluorite, richerite, enstatite, and wollastonite are a result of the erosion of the ophiolitic rocks from the surrounding Amanos Mountains. These levels are interpreted as corresponding to relatively high erosive periods, while more humid periods lead to more intensive weathering and consequently to the dominance of kaolinite, muscovite/illite and talc more advanced in the relative stability scale, indicating a climate with contrasting seasons. During the most recent Period a marked increase in terrigeneous minerals associated with a rise in dolomite indicates ungoing erosion as well as the drying-out of the lake. [less ▲]

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See detailContrasted terrace systems of the lower Moulouya valley as indicator of crustal deformation in NE Morocco
Rhixon, Gilles; Bartz, Melanie; El Ouahabi, Meriam ULg et al

Conference (2016, April 17)

The Moulouya has the largest catchment in Morocco and drains an area which is characterized by active crustal deformation during the Late Cenozoic due to the convergence between the African and Eurasian ... [more ▼]

The Moulouya has the largest catchment in Morocco and drains an area which is characterized by active crustal deformation during the Late Cenozoic due to the convergence between the African and Eurasian plates. As yet, its Pleistocene terrace sequence remains poorly documented. Our study focuses on the lowermost reach of the river in NE Morocco, which drains the Triffa sedimentary basin directly upstream of the estuary. New field observations, measurements and sedimentological data reveal contrasted fluvial environments on either side of a newly identified thrust zone, which disrupts the whole sedimentary basin and is associated with N–S compressive shortening in this region. Long-lasting fluvial aggradation, materialized by ≥37 m-thick stacked fill terraces, and the development of a well-preserved terrace staircase, with (at least) three Pleistocene terrace levels, occur in the footwall and the hanging wall of the thrust, respectively. Same as for the Pleistocene terrace sediments of the middle Moulouya, a recurrent sedimentary pattern, characterized by fining-upward sequences was observed in the studied terrace profiles. Assessing the rates of crustal deformation along this main thrust zone requires age estimations for these Pleistocene terrace deposits of the lower Moulouya on each side of the thrust. Samples for luminescence (OSL/IRSL), electron spin resonance (ESR) and cosmogenic nuclide dating (26Al/10Be, burial dating) were collected in terrace deposits located both in the foot- and hanging walls. Sample preparation and analysis as well as age determination are in progress. The preliminary data mentioned above, soon to be completed by chronological data, agree well with morphometric indicators stating that the whole Moulouya catchment is at disequilibrium state (Barcos et al., 2014). This is confirmed by several knickpoints in its longitudinal profile. Late Cenozoic uplift associated with crustal shortening, which occurred in the lowermost reach of the river, may have both hindered profile rectification of the Moulouya and, at the same time, buffered the effects of long-term base-level changes due to eustatic sea-level variations. [less ▲]

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See detailTowards a better understanding of ephemeral stream morphodynamics during the last 100 ka in the vicinity of the prehistoric site of Ifri n’Ammar (Morocco)
Bartz, Melanie; Rhixon; Khel, Martin et al

Conference (2016, April 17)

Our study focusses on the ephemeral stream deposits of Wadi Selloum to reconstruct the palaeoenvironmental evolution in direct vicinity of the rock shelter Ifri n’Ammar. As one of the oldest settlement ... [more ▼]

Our study focusses on the ephemeral stream deposits of Wadi Selloum to reconstruct the palaeoenvironmental evolution in direct vicinity of the rock shelter Ifri n’Ammar. As one of the oldest settlement sites of anatomically modern humans (AMH) in North Africa, Ifri n’Ammar documents periodical occupations since ~170 ka. Since these discontinuous settlement dynamics may be related to or influenced by landscape changes and climate forcing, our study aims (i) to identify phases of morphodynamic activity and stability in the deposits of Wadi Selloum by using micromorphological (sixteen thin sections), sedimentological (laser diffractometry, loss on ignition, magnetic susceptibility), geochemical ( XRF and Scheibler method) and mineralogical (X-ray diffractometry) proxies. Furthermore, (ii) a robust chronology for the ephemeral stream deposits is established by applying a combination of optically stimulated luminescence (OSL) and post infrared stimulated luminescence (pIRIR290) dating. Additionally, one collected pottery shard was dated by thermoluminescence (TL) dating for an inter method comparison. The application of luminescence dating techniques to Wadi Selloum deposits yielded burial ages between 1.3 ± 0.2 ka and 102 ± 8 ka covering different phases of morphodynamically stable and active phases. Enhanced aggradation is evident between ~100 and 60 ka, ~21 and 14 ka and during the Holocene. Overbank fines are distinguished by high amounts of allochthonous minerals such as quartz, muscovite, K-feldspar and plagioclase which give rise to higher eolian activity. This leads to the suggestion that morphodynamical activity was dominant during more arid phases. Landscape stability was observed in form of one palaeosol (2B-2C-sequence; OIS 3) and a recent soil (Ap/Ah-Bw-Bk-BC-C-sequence; after LGM), both attributed to the Calcisol group. Pedogenenesis is evident in thin sections by well-developed subangular blocky peds. The main soil forming process is secondary carbonate precipitation in subsoil horizons, supported by pedofeatures such as calcite infillings and hypocoatings. Holocene deposits (6.4 ± 4 to 1.3 ± 0.2 ka) seem to be affected by short-termed changes between landscape stability and hydromorphic activity due to strong variations in its mineralogical and geochemical characteristics. This is supported by a homogeneous and sterile stratigraphy, as well as an insignificant differentiation in soil horizons with only weakly developed pedofeatures. The sediment characteristics present a weak Ap-C-sequence of a calcaric Fluvisol. After ~1.3 ± 0.2 ka fluvial discharge was reduced and incision took place in the Wadi Selloum. Our study provides first insights in the palaeoenvironment around Ifri n’Ammar during the last glacial interglacial cycle and gives first suggestions about climatic conditions during the time of human occupation in Ifri n’Ammar. [less ▲]

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See detailHypnose: on it’s very existence
VANHAUDENHUYSE, Audrey ULg

Conference (2016, April 16)

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See detailActualités dans la prise en charge des tendinopathies
Kaux, Jean-François ULg

Conference (2016, April 16)

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See detailDrug-induced thyroid dysfunction
Geenen, Vincent ULg

Conference (2016, April 16)

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See detailLe manuel numérique
Vintila, Elena-Georgiana ULg

Scientific conference (2016, April 16)

Digital textbooks, their recent version, completely new in terms of form and presentation, have risen not only numerous economic or sociological, but also educational and pedagogical issues. Should the ... [more ▼]

Digital textbooks, their recent version, completely new in terms of form and presentation, have risen not only numerous economic or sociological, but also educational and pedagogical issues. Should the digital textbook replace the traditional, printed version? Or do we rather speak of a product altogether different, built on novel principles of subject matter exploitation and shaped according to a teaching philosophy that intensifies activism, interactivity, progression and creativity? We attempt to answer the two above mentioned questions by analyzing three FLE textbooks for A1 level learners. [less ▲]

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See detailLa Soif du mal : crime et alcool à l’écran
Tomasovic, Dick ULg

Conference given outside the academic context (2016)

Tout au long de son histoire, le cinéma policier a souvent associé l’alcool au crime. Des films de gangsters réalisés durant la prohibition au thriller contemporain, en passant par le film noir ... [more ▼]

Tout au long de son histoire, le cinéma policier a souvent associé l’alcool au crime. Des films de gangsters réalisés durant la prohibition au thriller contemporain, en passant par le film noir hollywoodien, l’eau-de-vie est souvent une eau de mort. La conférence s’intéresse particulièrement au célèbre film de William Wellman, "L’Ennemi public" (1931), le chef-d’oeuvre des films de gangsters avec James Cagney. [less ▲]

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See detailLe développement territorial en Wallonie : entre dispersion des populations et concentration de l'activité
Halleux, Jean-Marie ULg

Conference given outside the academic context (2016)

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