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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 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 detailBibliométrie et Open Access à l'ULg
Thirion, Paul ULg

Scientific conference (2015, April 01)

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See detailUsages de l'image dans les sciences de la vie : quelques réflexions constructivistes
Pieron, Julien ULg

Scientific conference (2015, April 01)

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See detailUncoupled and coupled hydrogeophysical inversions of seawater intrusion and geothermal hydrologic models
Beaujean, Jean ULg

Doctoral thesis (2015)

Most of humans live in coastal and alluvial plains. Sustainable water supply systems are essential for drinking water production while long-term groundwater access ensures its geothermal use. Owing to ... [more ▼]

Most of humans live in coastal and alluvial plains. Sustainable water supply systems are essential for drinking water production while long-term groundwater access ensures its geothermal use. Owing to climate change and anthropogenic activities, groundwater resources will be increasingly threatened throughout the twenty-first century. In the context of over-development, any effort to overcome groundwater mining at the expense of better understanding groundwater management problems may be misguided. A combination of robust measuring technologies and reliable predictions based on numerical models are necessary to estimate better hydrogeological parameters. Sparse and continuous data are increasingly being used conjunctively in hydrogeological modeling and inverse calibration to alleviate extrapolation and subjective interpretation. In hydrogeology, electrical resistivity tomography (ERT) gives quantitative and qualitative information on salinity and temperature distribution. ERT offers a means for mapping the subsurface hydrogeological structures and the hydrologic process dynamics in both space and time. The integration of ERT data to hydrogeological calibration is particularly suited to define the hydrogeological models quantitatively and qualitatively. In a deterministic framework, hydrogeophysical inversion methods may be particularly useful for predictive analysis and assessment of groundwater pre-emptive management strategies. This work focuses on calibrating physically-based and spatially distributed groundwater flow and transport models with non-to minimally invasive electrical tomography. The general objective is to provide better estimates of hydrogeological parameters on two relevant problems: seawater intrusion in coastal areas and geothermal energy in shallow environments. We compare methods to integrate quantitatively ERT data, possibly other hydrologic or geological data, with existing information to hydrogeological models. Two hydrogeophysical inversion schemes are developped and a thorough comparison of an uncoupled and a coupled quantitative approach based on the use of surface ERT only is performed. The uncoupled hydrogeophysical inversion involves constraining hydraulic parameters using geophysically-derived data and first requires a geophysical inversion, after which the geophysical parameters are converted to hydrologic data through a petrophysical relationship. The inverse hydrological calibration is then performed on these inferred hydrological data. The coupled hydrogeophysical inversion involves constraining hydraulic parameters using geophysical data through a forward hydrogeophysical model in which the hydrologic data are converted to resistivities through a petrophysical relationship. A geophysical forward problem is then solved for the geophysical data. The inverse hydrological calibration is performed on the inferred geophysical observations. In both schemes, we show that an independent geophysical inversion is required to delineate heterogeneous bodies. In this context, we study how to derive informative content of ERT images and therefore ERTderived hydrologic data and ERT-derived geometry. We show that a quantitative appraisal (the cumulative sensitivity) must be used as a proxy for filtering areas correctly resolved. Our developments are demonstrated on several benchmark SWI models (numerical and analytical), a thermohydrologic model and a field test. We show that the reliability of estimated SWI model parameters with the uncoupled approach depends on ERT image appraisal, on geophysical data collection strategy and hydrogeological model conceptualization. The ERT image appraisal plays a key role in retrieving high quality ERT-derived data and helps discriminate different measurement arrays. It is particularly useful in preventing the integration of noise-related artefacts in the conceptualization. We endeavor to quantify the modeling error by a thorough comparison of different strategies to assess the effect of decreasing model conceptual errors to hydrogeological calibration. In the SWI analytical models, we highlight the subjectivity of the uncoupled approach due to the nature of the required hydrologic data (sharp interface). We demonstrate that the conjunctive use of an image appraisal tool with the well-known Ghyben-Herzberg solution is needed to infer reliable ERT-derived observation data. We further demonstrate that a SWI analytical solution may be used to calibrate an equivalent hydraulic parameter based on an ERT dataset generated from a density-dependent groundwater flow model. In the thermohydrologic model, we show that the effectiveness of the uncoupled scheme in calibrating heat transport parameters may be hampered due to the regularization constraint in the geophysical inversion. We demonstrate the importance of a noise level-related filter on the time-lapse ERT images aimed at properly quantifying the spatio-temporal ERTderived temperature changes. We also advocate the use of a physically-based constraint on the ERT-derived temperatures to account for spatial mixing of waters and to cope indirectly with the smoothing effect in the ERT images. In each application, the coupled approach significantly prevails over the uncoupled scheme in terms of reliability of the parameter estimates when no model conceptual error exists. [less ▲]

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See detailDispositifs de conservation écorégionale et droits indigènes dans l’Amazonie Bolivienne: Les cas des Peuples du Madidi et Pilón Lajas
Marquez Guerra, José Francisco ULg

Doctoral thesis (2015)

The apparatus of conservation at the ecoregional scale integrating natural landscape and cultural landscapes in the Amazon basin has been introduced by international conservation NGOs since the beginning ... [more ▼]

The apparatus of conservation at the ecoregional scale integrating natural landscape and cultural landscapes in the Amazon basin has been introduced by international conservation NGOs since the beginning of the 90s when the term hotspot was invented to designate the importance of "mega-diversity "of tropical forests for the survival of humanity. The representation of environmental problems in the Amazon region as serious threats to life on the planet entered the political agenda of the international community becoming a matter of priority attention. To find solutions to this expanding threat, scientists, activists and interested parties have reflected on some formulas, innovative programs and strategies in order that cooperation and international aid could favor the action of effective conservation and sustainable development. The problem of resource degradation of biodiversity, and the loss of the values of cultural diversity of Amazonian peoples is since then conceived as a challenge that goes beyond national political interests, becoming a global issue. Bolivia was a breeding ground for these pioneering efforts, they have made a pragmatic view of international aid with new tools and effective techniques to combat emerging threats, one of them are financial mechanisms for conservation planning. These have entered the Bolivian legal system from the 80 which coincides with the modernization of the state, an ambitious development plan supported by the implementation of neoliberal measures to promote economic growth, administrative decentralization as a new form to exercise power by delegating powers to the departmental and municipal levels, popular participation, as legitimacy methodology, defining local actors and regional planning policy as a useful management of natural resources for sustainable development. International actors of conservation, a group of scientific elite and environmental activists in the country and leaders of local indigenous movements have played an important role before and after this neoliberal modernization in the implementation of an ecorregional conservation apparatus in the Bolivian Amazon. The objective of this transdisciplinaria research, is an ethnographic description, based on the theoretical and methodological repertoire of legal anthropology and sociology of ANT Translation, of how the practices and strategies of conservation at the ecoregional scale through its technical, financial and legal instruments configure the territories, affect social relations and transform representations and practices of the nature of Amazonian peoples Mosetene, Tsimane' Tacana, Quechua-Tacana and Leco. The traditional spaces of these peoples are in total or partially overlapping with the current Natural Park and Integrated Management Area Madidi and Biosphere Reserve and Indigenous Territory Pilón Lajas implemented as protected areas during the 90 In this context, challenges and current controversies looming over the planning and use of space at different scales between actors of the policies of sustainable development and conservation, local political elites and indigenous peoples. [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 detailLiterature Review Analysis on Energy Performance and Sustainable Buildings in Romania
Ana Mureșan, Adina; Attia, Shady ULg

Report (2015)

This work is a part of the Master of Science Thesis written during the mobility organized by the Erasmus + Programme for exchange students at Universite de Liege, in Belgium (Université de Liège, Belgique ... [more ▼]

This work is a part of the Master of Science Thesis written during the mobility organized by the Erasmus + Programme for exchange students at Universite de Liege, in Belgium (Université de Liège, Belgique), which is in bilateral agreement with Technical University of Cluj-Napoca, in Romania (Universitatea Tehnică din Cluj-Napoca, România) available between 2014 – 2020. The audience of this literature review is civil engineers and specialists in building energy and it aims to inform about the current state-of-the-art of the sustainable buildings design and energy performance in the Romanian context. The work presents the review of 35 publications chosen from the Literature Survey List which includes 80 publications. The publications included in the Literature Survey List are Romanian standards for energy performance in buildings, chapters from books and journal articles. The sources of the publications are included in the Resources Screening List. [less ▲]

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See detailLa narration en gravure et en bande dessinée
Paques, Frédéric ULg; Pinelli, Joe; Hardy, Chantal

Conference given outside the academic context (2015)

Cette tale ronde réunissait trois graveurs ayant la narration comme préoccupation première dans leur travail : Jean-Christophe Long, Thierry Lenoir et Sylvain Bureau

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See detailEfficacy of heroin-assisted treatment in Belgium: a randomised controlled trial
Demaret, Isabelle ULg; Quertemont, Etienne ULg; Litran, Géraldine et al

in European Addiction Research (2015), 21(4), 179-187

Background/Aims: Heroin-assisted treatment (HAT) can improve the condition of heroin addicts still using street heroin after a methadone treatment. In Belgium, a new trial compared the efficacy of a HAT ... [more ▼]

Background/Aims: Heroin-assisted treatment (HAT) can improve the condition of heroin addicts still using street heroin after a methadone treatment. In Belgium, a new trial compared the efficacy of a HAT to existing methadone maintenance treatment. Methods: In this randomised controlled trial, HAT was limited to 12 months. Participants were assessed every 3 months. They were responders if they showed improvement on the level of street heroin use, health or criminal involvement. Results: 74 participants were randomised in the trial. The experimental group (n=36) counted 30% of responders more than the control group (n=38) at each assessment point (p<0.05), except at 12 months where the difference (11%) was no longer significant (p=0.35). Still, after 12 months, participants in the experimental group reported significantly greater improvements (p<0.05) than the control group on the level of street heroin use and on the level of physical and mental health. Both groups reported significantly less criminal facts after 12 months (p<0.001), but with no significant difference between the groups. Conclusions: This trial confirms the short-term efficacy of HAT for severe heroin addicts, who already failed methadone treatment. [less ▲]

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See detailLe traité Sur l'exil de Favorinos d'Arles. Papyrologie, philologie et littérature
Amato, Eugenio; Marganne, Marie-Hélène ULg

Book published by Presses Universitaires de Rennes (2015)

Recherches sur les circonstances de l'acquisition du P. Vatic. Gr. 11, sur les conditions matérielles de la mise par écrit du traité De l'exil de Favorinos d'Arles au verso du rouleau de papyrus, et sur ... [more ▼]

Recherches sur les circonstances de l'acquisition du P. Vatic. Gr. 11, sur les conditions matérielles de la mise par écrit du traité De l'exil de Favorinos d'Arles au verso du rouleau de papyrus, et sur celles de sa composition et de son contexte littéraire. [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 detailL’anéantissement des donations : questions de droit international privé
Wautelet, Patrick ULg; Fongaro, Eric

in Revue de planification patrimoniale belge et internationale (2015), 2(1), 39-64

Avec le développement d'une véritable pratique transfrontière de la planification successorale, les questions de droit international privé entourant les donations ont beaucoup retenu l'attention ces ... [more ▼]

Avec le développement d'une véritable pratique transfrontière de la planification successorale, les questions de droit international privé entourant les donations ont beaucoup retenu l'attention ces dernières années. Cet intérêt renouvelé pour un sujet classique a permis d'élucider le statut pour le moins complexe de la donation qui présente une dimension internationale. On a toutefois peu évoqué les difficultés que peuvent susciter la fragilité des donations : institution de droit civil aux contours pour le moins polymorphes, la donation est entourée de nombreuses limitations et obstacles qui ont pour objectif de conjurer les risques que peut faire naître, tant pour le donateur, sa famille que pour ses créanciers, cet acte particulier d'appauvrissement sans contrepartie. Le régime contemporain des donations est fondé sur une série de règles et mécanismes qui permettent de remettre en question la libéralité. Tantôt c'est la capacité d'une des parties (à donner ou à recevoir) qui fait l'objet de dispositions dérogatoires au droit commun, tantôt c'est le consentement du donateur qui suscite l'application d'une règle spéciale, tantôt encore des exigences particulières sont posées à propos des formes que doit revêtir une donation. Ces règles complexes, qui nourrissent un contentieux fourni, sont autant d'obstacles qui peuvent être posés au plein accomplissement des donations. Elles conduisent parfois à la révocation de la donation, qui peut produire ses effets ex nunc ou dans certains cas de façon rétroactive. Dans d'autres situations, la donation est annulée et dès lors considérée comme n'ayant jamais existé. Une donation peut également faire l'objet d'une déclaration ou encore être frappée de caducité ou de déchéance. Ces questions sont abordées dans la présente contribution sous l'angle du droit international privé belge et français, en mettant l'accent tant sur les différences que sur les simillitudes entre ces droits. [less ▲]

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See detailTendon et acide hyaluronique
Kaux, Jean-François ULg; Samson, Antoine; Crielaard, Jean-Michel ULg

in Science & Sports (2015), 30(2), 57-65

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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 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 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 detailEffets de la modernisation de tannerie sur l’impact de ses activités sur la qualité des eaux : cas de la tannerie de Maradi au Niger
Saidou, H.; Laminou Manzo, O.; Ozer, Pierre ULg et al

in Research Inventy: International Journal Of Engineering And Science (2015), 5(4), 30-38

The modernization of the tannery of Maradi had intervened in 2009 with the introduction of the process of tanning in the chromium. We estimated the influence of this change of operating process through an ... [more ▼]

The modernization of the tannery of Maradi had intervened in 2009 with the introduction of the process of tanning in the chromium. We estimated the influence of this change of operating process through an evaluation of the impact characteristics evolution of the solid and liquid discharges of this tannery on water. It stands out that the modernization of the tannery activities had more or less significant effects on these environment elements. We noted a relative improvement of the quality of underground waters illustrated by the regression of the content in chloride and nitrates rates stabilization. While the content in chromium evolved in a significant way as well as the pH. However, all the four above parameters remain below WHO standards. By cons, this modernization has almost not influenced the impact on the quality of surface waters. The values of BOD and COD have continued to rise despite the installation of a treatment system. Thus this surface water, including the pond, proved to be a major public health risk for domestic and agricultural use and is also a source of air pollution. [less ▲]

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