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See detailImpact of tillage on CO2 and N2O efflux in an agricultural crop
Lognoul, Margaux ULg; Theodorakopoulos, Nicolas ULg; Hiel, Marie-Pierre ULg et al

Poster (2016, April 20)

CO2 and N2O fluxes exchanged by a maize crop were measured from June to Octboer 2015 using a homemade automated system of dynamic closed chambers. We studied the impact of tillage (reduced and ... [more ▼]

CO2 and N2O fluxes exchanged by a maize crop were measured from June to Octboer 2015 using a homemade automated system of dynamic closed chambers. We studied the impact of tillage (reduced and conventional) on greenhouse gas emissions and nitrous oxide flux dynamics. [less ▲]

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

Conference (2016, April 20)

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

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

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See detailVolunteering Citizens in Nuclear Risk Governance: Citizen Science after Fukushima
Van Oudheusden, Michiel ULg; Turcanu, Catrinel; Yoshizawa, Go et al

Conference (2016, April 20)

Citizen science (CS) is a form of science developed and enacted by citizens, typically with citizen volunteers collecting and/or analyzing various kinds of data. Whereas common forms of CS like bird ... [more ▼]

Citizen science (CS) is a form of science developed and enacted by citizens, typically with citizen volunteers collecting and/or analyzing various kinds of data. Whereas common forms of CS like bird counting and amateur astronomy generally elicit interest and approval on behalf of scientists, decision makers, and publics at large, CS in the nuclear field is far more contentious. This is due to the controversial nature of nuclear science and technology, as evidenced by public disputes about nuclear energy, nuclear waste management, and nuclear accidents, among others. Starting from these observations, this paper probes the risky, disputed character of CS in nuclear emergency and post-accident situations. It specifically looks at CS in Japan after the 2011 Fukushima Daiichi nuclear disaster, where citizens in affected areas monitor radioactivity in the environment and communicate about health and environmental risks with one another (e.g. Citizens’ Radioactivity Monitoring Project). In these processes, citizen scientists voice ardent criticism of government, industry, and academia, as these institutes are seen to deliberately spread biased information to sustain an illusion of control (http://blog.safecast.org). By taking science and technology into their own hands, they challenge conventional notions of citizen engagement, science, and avocation/volunteerism. The paper draws on the notions of contentious politics and issue politics (e.g. Marres 2005) to highlight the issue-driven, adversarial and untamed character of post-Fukushima CS in the nuclear field. It is argued that these notions better capture what CS after Fukushima amounts to, as conventional representations (e.g. volunteer sensing, “citizens as sensors,” public participation in scientific research) downplay scientific uncertainties and power asymmetries between citizens and authorities, and do not account for how “Fukushima” is reconfiguring scientific citizenship in novel ways. [less ▲]

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See detailThe last millenia sedimentary record of Lago Esponja from Northern Chilean Patagonia
Fagel, Nathalie ULg; Alvarez, Denisse; Araneda, Alberto et al

Poster (2016, April 20)

We evaluate the climate and environmental variability of Northern Chilean Patagonia during the Last Millennia, using a multi-proxy analysis of a sediment core from Lago Esponja (45°09’S, 72°08’W). The ... [more ▼]

We evaluate the climate and environmental variability of Northern Chilean Patagonia during the Last Millennia, using a multi-proxy analysis of a sediment core from Lago Esponja (45°09’S, 72°08’W). The lake is located in the region of Aysen del General Carlos Ibanez del Campo, in NW Patagonia. The study focuses on a multiproxy analysis of sedimentary records. The longest core (150 cm long) was collected in 2014 at 40 m depth. The sediment, which is composed of light brown organic-rich clayey silt, was analyzed for sedimentology (grain size, magnetic susceptibility organic matter and biogenic silica content), mineralogy (X-ray diffraction) and geochemistry (elemental and isotopic analyses of C and N, XRF core-scaner at 1 mm resolution). The radiocarbon ages, measured on 3 macro-remains, demonstrate that the core covers the last 6.700 years. The sedimentation rate ranges between 0.1 mm/yr in the lower section (100-150 cm) and 0.4 mm/yr in the upper meter. Visual descriptions and Scopix radiographies show that the sediment record is finely laminated except a massive decimetric coarser and darker layer corresponding to a tephra (estimated age 700AD±50). Magnetic susceptibility (confirmed by scopix radiographies) highlights the presence of 8 additional millimetric tephra layers. The biogenic silica content of the sediment is low (mean 5%). Diatom assemblage is dominated by benthic and acidophilous species, with high saprobic values. None marked changes were observed regarding the dynamic of the lake. The high organic matter content (mean 15%) and its high C/N ratio (12.7) throughout the core indicate inputs of allochtonous and terrestrial organic matter. Such parameters present high sediment variability also marked by changes in the chemical composition. The laminations reflect changes in the allochtonous sedimentary inputs, with high terrestrial inputs during wetter conditions in relation with the Westerlies. The sedimentary records of Lago Esponja will be compared with Eastern lacustrine record from the same latitude in order to confirm the climate-driven record. [less ▲]

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See detailCyclic and oligo-carbonates by organocatalytic coupling of CO2 with epoxides or oxetanes
Alves, Margot ULg; Grignard, Bruno ULg; Boyaval, Amélie ULg et al

Conference (2016, April 20)

Valorising CO2 as a renewable C1 feedstock for producing added value building blocks is the scope of many academic and industrial researches. Carbon dioxide is a thermodynamically and kinetically stable ... [more ▼]

Valorising CO2 as a renewable C1 feedstock for producing added value building blocks is the scope of many academic and industrial researches. Carbon dioxide is a thermodynamically and kinetically stable molecule that can be converted into five and six membered cyclic carbonates by coupling with epoxides or oxetanes, respectively, using appropriate catalysts. Although transition metal catalysts are efficient under atmospheric pressure and ambient temperature, most of them are poorly selective, sensitive to hydrolysis and/or oxidation and/or toxic whereas less/non-toxic and eco-friendly organocatalysts such as ionic liquids and halide salts are generally only efficient at very high temperature and pressure favouring their thermal degradation. To overcome these limitations, we developed a new highly efficient bicomponent homogeneous organocatalyst composed of an ammonium salt as the catalyst and fluorinated single or double hydrogen bond donor activators. Through online FTIR kinetic studies, we demonstrated that this new organocatalyst showed unexpected catalytic activity for the fast and selective addition of CO2 onto epoxides under solvent-free and mild experimental conditions. The use of this dual catalyst was then extended to the coupling of CO2 with less reactive oxetanes to produce hydroxyl telechelic oligocarbonates. In the first part of this talk, based on kinetics of reactions followed by online FTIR under pressure, we will describe the reaction conditions required for the organocatalytic coupling of CO2 with epoxides and oxetanes. In the second part, the mechanism of the reaction will be approached and discussed based on DFT calculations. Finally, we will compare and discuss the efficiency of various organocatalytic systems for this type of reaction. [less ▲]

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Peer Reviewed
See detailHeat tracer test in an alluvial aquifer: field experiment and inverse modelling
Klepikova, Maria; Wildemeersch, Samuel; Jamin, Pierre ULg et al

Poster (2016, April 20)

Using heat as an active tracer for aquifer characterization is a topic of increasing interest. In this study, we investigate the potential of using heat tracer tests for characterization of a shallow ... [more ▼]

Using heat as an active tracer for aquifer characterization is a topic of increasing interest. In this study, we investigate the potential of using heat tracer tests for characterization of a shallow alluvial aquifer. A thermal tracer test was conducted in the alluvial aquifer of the Meuse River, Belgium. The tracing experiment consisted in simultaneously injecting heated water and a dye tracer in a piezometer and monitoring the evolution of groundwater temperature and tracer concentration in the recovery well and in monitoring wells. To get insights in the 3D characteristics of the heat transport mechanisms, temperature data from a large number of observation wells distributed throughout the field site (space-filling arrangement) were used. Temperature breakthrough curves in observation wells are contrasted with what would be expected in an ideal layered aquifer. They reveal strongly unequal lateral and vertical components of the transport mechanisms. The observed complex behavior of the heat plume was explained by the groundwater flow gradient on the site and heterogeneity of hydraulic conductivity field. Moreover, due to high injection temperatures during the field experiment a temperature-induced fluid density effect on heat transport occurred. By using a flow and heat transport numerical model with variable density coupled with the pilot point inverse approach, main preferential flow paths were delineated. [less ▲]

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Peer Reviewed
See detailDecrease in hydroclimatic conditions generating floods in the southeast of Belgium over the last 50 years
Wyard, Coraline ULg; Fettweis, Xavier ULg

Conference (2016, April 19)

As a consequence of climate change, several studies concluded that winter flood occurrence could increase in the future in many rivers of northern and western Europe in response to an increase in extreme ... [more ▼]

As a consequence of climate change, several studies concluded that winter flood occurrence could increase in the future in many rivers of northern and western Europe in response to an increase in extreme precipitation events. This study aims to determine if trends in extreme hydroclimatic events generating floods can already be detected over the last century. In particular, we focus on the Ourthe River (southeast of Belgium) which is one of the main tributaries of the Meuse River with a catchment area of 3500 km² . In this river, most of the floods occur during winter and about 50% of them are due to rainfall events associated with the melting of the snow which covers the Ardennes during winter. In this study, hydroclimatic conditions favourable to floods were reconstructed over the period 1959-2010 using the regional climate model MAR (“Modèle Atmosphérique Régional”) forced by the following reanalyses: the ERA-20C, the ERA-Interim and the NCEP/NCAR-v1. The use of the MAR model allows to compute precipitation, snow depth and run-off resulting from precipitation events and snow melting in any part of the Ourthe river catchment area. Therefore, extreme hydroclimatic events, namely extreme run-off events, which could potentially generate floods, can be reconstructed using the MAR model. As validation, the MAR results were compared to weather station-based data. A trend analysis was then performed in order to study the evolution of conditions favourable to flooding in the Ourthe River catchment. The results show that the MAR model allows the detection of about 90% of the hydroclimatic conditions which effectively generated observed floods in the Ourthe River over the period 1974-2010. Whatever the reanalysis used to force the MAR model, the conditions favourable to floods due to snowpack melting combined with rainfall events present a significant negative trend over the last 50 years as a result of a decrease in snow accumulation. However, regarding the conditions favourable to floods due to rainfall events alone, the signal of the trend depends on the reanalysis used to force the model. [less ▲]

Detailed reference viewed: 8 (4 ULg)
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See detailUsing NDACC column measurements of carbonyl sulfide to estimate its sources and sinks
Wang; Marshall, J; Palm, M et al

in Geophysical Research Abstracts (2016, April 19), 18

Detailed reference viewed: 10 (3 ULg)
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See detailAppropriability and the European Commission’s Android Investigation
Auer, Dirk ULg

E-print/Working paper (2016)

This paper seeks to ascertain whether Google’s Android licensing terms, which are currently under scrutiny from the European Commission, could be excused under an innovation defense framework. The paper ... [more ▼]

This paper seeks to ascertain whether Google’s Android licensing terms, which are currently under scrutiny from the European Commission, could be excused under an innovation defense framework. The paper starts by analyzing Google’s business model with regard to its Android OS. It then identifies the Commission’s main concerns. It argues that Google is simply pursuing a sensible appropriation strategy. Finally, it puts forward a framework which hinges on the concept of “appropriability”, and tentatively applies it to Google’s behavior. [less ▲]

Detailed reference viewed: 24 (2 ULg)
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Peer Reviewed
See detailA Raster SOLAP for the Visualization of Crime Data Fields
Kasprzyk, Jean-Paul ULg; Donnay, Jean-Paul ULg

in Rückemann, Claus-Peter (Ed.) GEOProcessing 2016 (2016, April 19)

In order to effectively extract synthetic information from large spatial data sets, Spatial OnLine Analytical Processing (SOLAP) combines Geographic Information Systems (GIS) with Business Intelligence ... [more ▼]

In order to effectively extract synthetic information from large spatial data sets, Spatial OnLine Analytical Processing (SOLAP) combines Geographic Information Systems (GIS) with Business Intelligence (BI) to query data warehouses through interactive vector maps. On the other hand, crime strategical analysis is usually based on raster maps computed by Kernel Density Estimation (KDE), then independent of any artificial boundary. This paper introduces an alternative vision of SOLAP which uses the raster model (instead of the vector one) in order to integrate crime data fields computed by KDE. It allows a continuous visualization of spatial data which, until now, has not been compatible with other SOLAP tools. The original geo-model is validated by a prototype adapted to the police needs. [less ▲]

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

Scientific conference (2016, April 18)

Detailed reference viewed: 13 (0 ULg)
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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 ▲]

Detailed reference viewed: 13 (1 ULg)
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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 ▲]

Detailed reference viewed: 8 (2 ULg)
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

Detailed reference viewed: 10 (1 ULg)
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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 detailEmilio Salgari e l’avventura
Curreri, Luciano ULg

Scientific conference (2016, April 18)

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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 ▲]

Detailed reference viewed: 10 (1 ULg)
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 ▲]

Detailed reference viewed: 43 (5 ULg)