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See detailImpact of abiotic stresses on volatile organic compound production of field crops and grasslands
Digrado, Anthony ULg; Mozaffar, Ahsan ULg; Bachy, Aurélie ULg et al

Poster (2014, February 07)

Abiotic and biotic stresses are known to alter biogenic volatile organic compound (BVOC) emission from plants. With the climate and global change, BVOC emissions are likely to increase. This increase on ... [more ▼]

Abiotic and biotic stresses are known to alter biogenic volatile organic compound (BVOC) emission from plants. With the climate and global change, BVOC emissions are likely to increase. This increase on BVOC emissions could be driven by many environmental parameters like temperature, ozone and light availability for photosynthesis although it is still difficult to predict the impact of some environmental parameters, environmental controls on BVOC emission being species and BVOC-dependent. These BVOC are involved in a wide range of interactions of plants with their environment and these interactions could be affected by the global change. Moreover, BVOC also play a key role in the atmospheric chemistry and may contribute to ozone formation and an increase in methane lifetime, strengthening the global change. Yet, due to technical limitation, there are few studies examining the impact of multiple co-occurring stresses on BVOC emission at the ecosystem level although stress combination is probably more ecologically realistic in field. In the CROSTVOC (for CROp STress VOC) project, the impact of abiotic stresses (e.g. heat, drought, ozone and grazing) on BVOC emission will be investigated for field crops (maize and wheat) and grassland both at the ecosystem and plant scale. [less ▲]

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See detailThree aspects, One concept: Agroecology. Agroecological practices and human interactions for a new approach for science. An example at the Univeristy of Liege.
Hatt, Séverin ULg; Artru, Sidonie ULg; Boeraeve, Fanny et al

Poster (2014, February 07)

Critics are raising about conventional farming and its consequences on biodiversity, human health and society. As alternatives, novel models for agriculture are proposed, and among them Agroecology. Quite ... [more ▼]

Critics are raising about conventional farming and its consequences on biodiversity, human health and society. As alternatives, novel models for agriculture are proposed, and among them Agroecology. Quite often, Agroecology is seen as the application of ecological knowledge to the agricultural production. Indeed, this helps to develop more ecological farming practices favoring biodiversity to provide ecosystem services at multiple scales. Agroecology goes further in considering that the agricultural production is integrated in a food system guided by human interactions. This latter one takes into account socio-economic and political dimensions to develop new production systems. Doing so, it assures food security worldwide while preserving resources for future generations. Facing these ambitious objectives, academics are invited to elaborate a new approach for science in developing participatory and action-oriented approaches as well as multidisciplinarity. AgricultureIsLife is a research platform built up at the University of Liège (ULg). In 2013, 40 researchers (including 18 young researchers) from 16 research units of ULg were working in a multidisciplinary approach. About twenty research topics have been divided in four research axes of which objectives are to develop a more sustainable agriculture. The platform has the ambition to discuss its results to a large comity gathering the actors of the agricultural development. The aim of our work is firstly to present Agrocology as a concept made of three interrelated aspects. To illustrate it, the organization and objectives of the research platform AgricultureIsLife will be discussed in a second part. [less ▲]

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See detailInteractions between new phenolic glycolipids and model membrane
Sainvitu, Pauline ULg; Nasir, Mehmet Nail ULg; Crowet, Jean-Marc ULg et al

Poster (2014, February 07)

Model membrane based on phospholipids (PL) layers are useful to mimic properties of plasma membranes. The interactions between new synthesized phenolic glycolipids (PGL) and biological membrane are ... [more ▼]

Model membrane based on phospholipids (PL) layers are useful to mimic properties of plasma membranes. The interactions between new synthesized phenolic glycolipids (PGL) and biological membrane are crucial to determine their potential as drug candidates and their cytotoxicity . [less ▲]

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See detailBiodiversity and ecosystem services: think functional!
Uyttenbroeck, Roel ULg; Hatt, Séverin ULg; Paul, Aman ULg et al

Poster (2014, February 07)

During the last years, several studies and reviews have considered the relation between biodiversity and ecosystem functioning or the provision of ecosystem services. Many studies found that plant ... [more ▼]

During the last years, several studies and reviews have considered the relation between biodiversity and ecosystem functioning or the provision of ecosystem services. Many studies found that plant functional traits and plant functional diversity (FD) are key drivers in this relation in terrestrial ecosystems. Researchers used different methods to obtain a gradient in plant FD to examine the effect on ecosystem services, going from observational studies of natural communities to synthetic assemblages. Furthermore, different methods exist to quantify plant FD going from simple functional trait richness to indices, distance-based frameworks and the division into FD components. In the AgricultureIsLife project, we set up a field experiment aiming to examine the biodiversity – ecosystem service relation in agricultural context. The experiment consists of perennial wildflower strips with different plant functional diversities in an arable field with conventional crop production. The wildflower strips were sown as synthetic assemblages but are subject to natural succession during the following years. We monitor the evolution of FD from the sowing to the establishment of a typical wildflower strip using Rhao’s quadratic entropy index to quantify FD. In addition, the flower strips will be monitored for four ecosystem services they are expected to provide: pollination, pest control, biodiversity support and provision of valuable compounds. [less ▲]

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See detailEfficient computation of genomically-enhanced inbreeding coefficients
Faux, Pierre ULg; Gengler, Nicolas ULg

Poster (2014, February 07)

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See detailSreening of essential oils against rice pathogens isolated from Madagascar
Mamiharisoa Razanakoto, Léa ULg; De Clerck, Caroline ULg; Massart, Sébastien ULg et al

Poster (2014, February 07)

Four predominant isolated pathogens have been identified during survey of rice diseases in three regions in Madagascar. These pathogens were the bacteria Xanthomonas oryzae pv. oryzae and Pseudomonas ... [more ▼]

Four predominant isolated pathogens have been identified during survey of rice diseases in three regions in Madagascar. These pathogens were the bacteria Xanthomonas oryzae pv. oryzae and Pseudomonas fuscovaginae and the fungi Alternaria sp. and Curvularia lunata. These pathogens are causing significant yield reduction on rice, which is the staple food in this country. After the identification of those pathogens, the objective of this work was to identify appropriate control measures against them. Plants extracts has been traditionally used to control diseases in other plant species. Nowadays, the problem of residues of phytopharmaceutical product, reinforce the need for research on the development of natural plant extracts to control plant diseases. Madagascar has many endemic plant of interest and we have evaluated the antimicrobial properties of essential oils from Malagasy plants. The main object of this study is the in-vitro screening of essential oils to control the pathogens isolated on rice in Madagascar. Thirty nine essentials oils from Madagascar had been tested. Activity of essentials oils on Pseudomonas fuscovaginae, Alternaria sp. and Curvularia lunata had been tested using broth media and on agar medium for Xanthomonas oryzae pv. oryzae. The growth of the pathogen (bacteria and conidia) in the presence of the essential oil was evaluated and compared to a control. Nine of the 39 essentials oils showed interesting antimicrobial activity with an efficiency more than 70% against at least one bacterial pathogen. One essential oil inhibited the growth of the two pathogens tested. For fungal pathogens, three essential oils presented an efficiency of more than 70% against at least one fungal pathogen. These results confirm that some essential oils present an interesting antimicrobial activity. The in-situ confirmation on plant of this activity is currently ongoing. [less ▲]

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See detailIncrease in Soil Macroporosity managed with Winter Ploughing - a preliminary results
Parvin, Nargish ULg; Chelin, Marie ULg; Hiel, Marie-Pierre ULg et al

Poster (2014, February 07)

Measurement of soil water retention capacity by the conventional pressure plate technique always gives a substantial view of soil porosity distribution. The structural orientation is observed in the ... [more ▼]

Measurement of soil water retention capacity by the conventional pressure plate technique always gives a substantial view of soil porosity distribution. The structural orientation is observed in the beginning (higher water retention at 9.8 to 98 hPa water head pressure indicates greater proportion of macroporosity) of the soil moisture characteristic curve obtained from the water retention measurement. Since, tillage practices generally increase soil porosity, the correlation between soil hydraulics and porosity distribution would expect to be different for different tillage systems. In general, macroporosity increase with the adoption of conservative tillage or no tillage system but the changes can be varied with the seasonal variation. In our study, winter ploughing retains more water at the range of 9.8 to 98 hPa than Strip tillage, No-till residues in and No-till residues out. So, we can conclude that there is certainly increase in macroporosity in ploughing than other conservation practices of reduced tillage and no tillage. [less ▲]

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See detailField bordering flower strips as source of lipids
Paul, Aman ULg; Danthine, Sabine ULg; Stephanie, Heuskin et al

Poster (2014, February 07)

Field bordering flower strips not just only improves the biodiversity but also serves as a source of beneficial compounds. Some of the plants in these strips can be really interesting source of lipids ... [more ▼]

Field bordering flower strips not just only improves the biodiversity but also serves as a source of beneficial compounds. Some of the plants in these strips can be really interesting source of lipids, the oils extracted from their seeds can be important for food, pharmaceutical and cosmetics industries. Six species of plants from flowering strips in Belgium were investigated for their seed oil content. The oil from seeds was extracted by cold extraction technique using chloroform/methanol in 2:1 ratio as solvent. Oil extraction from seeds of Red Clover (Trifolium pratense), Rough Hawkbit (Leontodon hispidus), Cow Parsley (Anthriscus sylvestris), St John’s Wort (Hypericum perforatum), Common Yarrow (Achillea millefollium) and Birdsfoot Trefoil (Lotus corniculatus) plant species was done on wet weight which came out to be 7.89±0.11%, 11.86±0.07%, 14.78±0.31%, 24.20±0.02%, 20.08±0.15% and 7.04±0.12% respectively. The physicochemical properties of the extracted oils were analyzed. Some of these oils can be of great commercial value. [less ▲]

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See detailQuantitative gas chromatography - mass spectrometry profiling of volatile organic compounds produced by barley (Hordeum distichon L.) roots according to plant age
Delory, Benjamin ULg; Delaplace, Pierre ULg; du Jardin, Patrick ULg et al

Poster (2014, February 07)

In chemical ecology, the roles played by root-emitted volatile organic compounds (VOCs) in biotic interactions and the quantitative analysis of such chemicals in root tissues remain poorly documented. In ... [more ▼]

In chemical ecology, the roles played by root-emitted volatile organic compounds (VOCs) in biotic interactions and the quantitative analysis of such chemicals in root tissues remain poorly documented. In this context, this study aims at developing a fully automated analytical methodology allowing both identification and accurate quantification of VOCs produced by roots of a monocotyledon plant species. Briefly, VOC emitted by crushed barley roots are successively trapped by dynamic headspace sampling on Tenax TA adsorbents, thermally desorbed and cryofocused, separated by gas chromatography (GC) and finally analysed by mass spectrometry (MS) in both SCAN and selected ion monitoring modes. Results show that barley roots mainly produce four volatile aldehydes, namely hexanal, (E)-hex-2-enal, (E)-non-2-enal and (E,Z)-nona-2,6-dienal. These molecules are well-known linoleic (C18:2) and linolenic (C18:3) acid derivatives produced via the lipoxygenase and the hydroperoxide lyase pathways of higher plants. Our findings contrast with analyses documented on aboveground barley tissues that mainly emit C6 aldehydes, alcohols and their derivative esters. Moreover, preliminary results indicate quantitative changes in the volatile profile contained in barley roots according to plant age. Multivariate statistical analyses are currently underway to quantitatively assess these changes using plants at five selected developmental stages ranging from germination to the end of tillering. [less ▲]

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See detailPrerequisites for a Black locust genomic selection program
Verdu, Cindy ULg; Mengal, Coralie ULg; Henrotay, Frédéric ULg et al

Poster (2014, February 07)

The use of renewable resources as an alternative to fossil fuels has become a priority. Efficient use of forest as a resource for energy and green chemistry purposes require the development of suitable ... [more ▼]

The use of renewable resources as an alternative to fossil fuels has become a priority. Efficient use of forest as a resource for energy and green chemistry purposes require the development of suitable selected genotypes that are competitive and ready to meet the challenges of global change. In this context, the black locust, Robinia pseudoacacia L., is a very promising species which has many advantages in the context of current global change: high phenotypic plasticity, drought resistance, high biomass production and fixation of atmospheric nitrogen. The genetic improvement of woody species using traditional methods can take between 20 to 30 years. These times can be greatly reduced with the development of new selection methods such as genomic selection. Before starting a genomic selection program, it is necessary to 1) develop new molecular markers to achieve a very dense genetic map for genomic selection, 2) study the genetic diversity of the species present in Belgium and compare it with that of the native area, 3) study the structure and the relatedness of different populations, 4) establish a core collection gathering the most genetically diverse individuals, and 5) as black locust is an exotic species, verify its invasiveness in Belgium. These 5 steps will be detailed and the first results obtained will be discussed. [less ▲]

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See detailINFLUENCE OF STEAM EXPLOSION ON THECRYSTALLINITY OF CELLULOSE FIBER
Jacquet, Nicolas ULg; Vanderghem, Caroline ULg; Danthine, Sabine ULg et al

Poster (2014, February 07)

The aim of the present study is to compare the effect of different steam explosion treatments on crystallinity properties of a pure bleached cellulose. Steam explosion process is composed of two distinct ... [more ▼]

The aim of the present study is to compare the effect of different steam explosion treatments on crystallinity properties of a pure bleached cellulose. Steam explosion process is composed of two distinct stages: vapocracking and explosive decompression. The treatment intensities is determined by a severity factor, established by a correlation between temperature process and retention time. The results show that steam explosion treatment has an impact on the crystallinity properties of pure cellulose fiber. When the severity factor is below 5.2, an increase of the overall crystallinity of the samples is observed with the treatment intensities. For higher intensities, a significant thermal degradation of cellulose lead to an important change in substrate composition, which lead to a further decrease of cellulose crystallinity. [less ▲]

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See detailUse of lipases for the kinetic resolution of lactic acid esters in heptane or in a solvent free system
Richard, Gaetan ULg; Nott, Katherine; Nicks, François et al

Poster (2014, February 07)

This poster illustrates the kinetic resolution of lactic acid esters using CAL-B as catalyst. The racemic mixture is resolved in heptane and even in a solvent free system.

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See detailarchiDART: a R package allowing root system architecture analysis using Data Analysis of Root Tracings (DART) output files
Delory, Benjamin ULg; Baudson, Caroline ULg; Brostaux, Yves ULg et al

Poster (2014, February 07)

In 2010, Le Bot et al presented a free and open-access software (Data Analysis of Root Tracings - DART) allowing the analysis of complex root system architectures from captured images, particularly across ... [more ▼]

In 2010, Le Bot et al presented a free and open-access software (Data Analysis of Root Tracings - DART) allowing the analysis of complex root system architectures from captured images, particularly across time series. Using this software, a user has to manually identify roots as a set of links. After vectorization of a root system, three final data sets (RAC, TPS and LIE) can be exported as table files containing several attributes for (a) each individual root (e.g. root length), (b) each observation day or (c) each point used to construct the vectorized root system respectively. These data sets can finally be used either to calculate derived root system architecture (RSA) parameters or to draw the root system architecture at selected observation dates. However when an experiment involves the analysis and comparison of many root systems, the calculation of RSA parameters for each data set and the drawing of the corresponding vectorized root systems become time-consuming. In this context, we developed a R package, called archiDART, allowing both the automatic calculation of common root architecture parameters and the X-Y plotting of vectorized root systems for selected observation dates. [less ▲]

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See detailRobot weed killers - no pain more gain
Krishna Moorthy Parvathi, Sruthi Moorthy ULg; Mercatoris, Benoît ULg; Boigelot, Bernard ULg

Poster (2014, February 07)

Weed destruction plays a significant role in crop production, and its automation has both economic and environmental benefits by minimizing the usage of chemicals in the fields. Our aim is to design a ... [more ▼]

Weed destruction plays a significant role in crop production, and its automation has both economic and environmental benefits by minimizing the usage of chemicals in the fields. Our aim is to design a small low-cost versatile robot allowing the destruction of weeds that lie between the crop rows by navigating in the field autonomously. Major challenges foreseen are: mapping the unknown geometry of the field, high-level planning of efficient and complete coverage of the field, and controlling the low-level operations of the robot. Traditionally, sensors like odometer have been used for localisation of robots but without much success in real-world scenarios. Specialized sensors like cameras will therefore be investigated and the plethora of image recognition algorithms will be explored and fine-tuned to enable Simultaneous Localisation And Mapping (SLAM) even on resource constrained robotic platforms. Vision-based localisation is not always viable because of the varying weather conditions of the environment and to overcome that, intelligent stochastic data fusion and machine learning algorithms will be utilized to combine data from heterogenous sensor. The image sensors for localisation will be re-used to differentiate crop rows from the weeds, which are cut when they grow. Finally, logics and reinforcement learning techniques will be explored, to exploit the generated map of the field and other sensorial information, to efficiently plan and execute weed elimination. [less ▲]

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See detailAllelopathic potential of sunflower against the great brome
Bouhaouel, Imen ULg; Gfeller, Aurélie; Fauconnier, Marie-Laure ULg et al

Poster (2014, February 06)

Control methods commonly used to suppress the great brome (Bromus diandrus Roth., syn. Bromus rigidus Roth. subsp. gussonii Parl.) in Tunisian cereal crop are essentially chemical, raising both efficacy ... [more ▼]

Control methods commonly used to suppress the great brome (Bromus diandrus Roth., syn. Bromus rigidus Roth. subsp. gussonii Parl.) in Tunisian cereal crop are essentially chemical, raising both efficacy and safety issues. The introduction of allelopathic species into the crop rotation or utilizing allelopathic plants as living/green mulches has been suggested as a cost-effective way to reduce the weed presence. Among these species, the sunflower (Helianthus annuus L.) has shown an allelopathic potential against some troublesome weed species. In this study, we analyzed the biological activities of water extract of different tissues (root, shoot, leaf and flower) of sunflower on the seedling establishment of the great brome. In a second experiment, the allelopathic influence of sunflower residues (leaf or flower) against this weed was also studied under glasshouse conditions at more advanced stages of growth using different concentrations (0, 6, 12 and 18g tissue dry weight / kg of soil). The first experiment showed an effect depending on the parts of the sunflower. Indeed, the roots seem to be the less allelopathic part (22% of root inhibition growth) as compared to the leaves and flowers (82% and 100%, respectively). This potential seems to simultaneously affect the radicle and the coleoptile growth of the great brome. In the second experiment, weed growth was inhibited in a dose-dependent manner, using increasing amounts of sunflower residues. The allelopathic potential of the leaves or flowers reduced both the root or shoot length and biomass accumulation of the weed. These results suggest that the sunflower can be a good previous crop for cereal cultivation by controlling the presence of some weeds, including the great brome. In this perspective, the inhibitory effects of sunflower residues on cultivated cereals in the field need to be assessed. [less ▲]

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See detailPaleoenvironmental record of the Amik Basin (Amuq Plain, Southern Turkey) over the last 4000 years
Hubert, Aurelia ULg; El Ouahabi, Meriam ULg; Lebeau, Hélène ULg et al

Poster (2014, February 04)

Continous human occupation is attested in the Amik Basin since 6000-7000 BC. The low-lying Amuq plain is covered by tell settlements first explored by Robert Braidwood in the 1930s. The Basin also is ... [more ▼]

Continous human occupation is attested in the Amik Basin since 6000-7000 BC. The low-lying Amuq plain is covered by tell settlements first explored by Robert Braidwood in the 1930s. The Basin also is crossed by The Dead Sea Fault (DSF), a major neotectonic structure in the Middle East extending from the Red Sea in the south to Turkey in the north. 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 assess possible human impact. The lake has been drained and progressively dried up since the mid-50s so that it is not watered during the summer season and constitutes a unique opportunity to collect sediment records. Sediments were collected at 1 cm to 2 cm intervals in a trench and in cores up to a depth of 5 meters in the clay deposits. A diverse array of complementary methods is applied to study the records: magnetic susceptibility, grain size, organic matter and inorganic carbon (L.O.I), XRD mineralogy, XRF geochemistry, carbon geochemistry. The age of the record is constrained combining radionuclide and radiocarbon dating. The record shows two intense phases of soil erosion with enrichments in Chromium and Nickel. The most recent erosion phase might be linked with enhanced development during the Roman and the growth of the Antioch City. The oldest one would occur around 3000 BC. The record also allows reconstructing past lake level variations and discusses the results in comparison with variations of the Dead Sea. [less ▲]

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See detailImportance of recent extreme weather variation in Djibouti and need for impact quantification
Nour Ayeh, Moustapha; Mahamoud, Ayan; Saad, Osman et al

Poster (2014, February)

This analysis shows that the current rainfall deficit is exceptional and historically unique. The significant population migration induced by the drought to Djibouti city must be supervised, especially ... [more ▼]

This analysis shows that the current rainfall deficit is exceptional and historically unique. The significant population migration induced by the drought to Djibouti city must be supervised, especially during their spontaneous settling. This presented example confirms that current rainfall shortages and increasing temperature extremes are impactinglocal people who urgently need adaptation and DRR strategies. It is necessary to reduce exposure to hydrological risks of these affected populations, in order that victims of the drought are not carried away by a rainfall excess. [less ▲]

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See detailSoil Seed Bank : a poorly know component of forest regeneration
Douh, Chauvelin ULg; Daïnou, Kasso ULg; Fernandez Pierna, Juan-Antonio et al

Poster (2014, February)

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See detailMicrofluidic on optical fibers: Towards a new kind of fluorescent biosensor
Lismont, Marjorie ULg; Vandewalle, Nicolas ULg; Weyer, Floriane ULg et al

Poster (2014, February)

In recent works, the behavior of droplets moving along vertical treads due to gravity was studied. It appeared that the droplet can be stopped by encountering a horizontal fiber depending on droplet ... [more ▼]

In recent works, the behavior of droplets moving along vertical treads due to gravity was studied. It appeared that the droplet can be stopped by encountering a horizontal fiber depending on droplet volumes and fiber characteristics. On the basis of this behavior and by replacing treads by two crossed optical fibers, it is possible to combine fluidics and optics to develop a new kind of fluorescent sensor. In our work, the intersection between two crossed optical fibers is used as the basic unit of an original optofluidic biosensor. These two optical fibers are used as droplets carriers: one for probe molecules and the other one for target species. The fiber's junction catches the droplets and act as a reaction center. The main advantage of using optical fibers resides in their ability to propagate and collect light to and from the droplet localized at the fiber's crossing. This optical fiber configuration can therefore allow the study of biological interactions using fluorescent labels. This new and versatile detection scheme was validated on a calcium indicator where ions detection is accomplished by using a dye, Oregon green Bapta-2, that has a Ca 2+ recognition group as well as an entity exhibiting fluorescence. A FRET recognition event, between Rh-Con A and FITC-Dextran, was also investigated to detect glucose. Finally, a prototype of a multiplexing device, composed of several juxtaposed fibers' junctions, was developed. [less ▲]

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See detailExploration on structure activity relation of natural, self-assembling cyclic lipodepsipeptides
Geudens, Niels; Feher, Kristina; De Vleeschouwer, Matthias et al

Poster (2014, February)

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See detailCan a global dynamic vegetation model be used for both grassland and crop modeling at the local scale?
Minet, Julien ULg; Tychon, Bernard ULg; Jacquemin, Ingrid ULg et al

Poster (2014, February)

We report on the use of a dynamic vegetation model, CARAIB, within two modeling exercises in the framework of MACSUR. CARAIB is a physically-based, mechanistic model that calculates the carbon ... [more ▼]

We report on the use of a dynamic vegetation model, CARAIB, within two modeling exercises in the framework of MACSUR. CARAIB is a physically-based, mechanistic model that calculates the carbon assimilation of the vegetation as a function of the soil and climatic conditions. Within MACSUR, it was used in the model intercomparison exercises for grassland and crop modeling, in the LiveM 2.4 and CropM WP4 tasks, respectively. For grassland modeling, blind model runs at 11 locations were performed for various time ranges (few years). For crop modeling, a sensitivity analysis for building impact response surfaces (IRS) was performed, based on a bench of model runs at different levels of perturbation in the temperature and precipitation input data over 30 years. For grassland modeling, specific management functions accounting for the cutting or grazing of the grass were added to the model, in the framework of the MACSUR intercomparison. Initially developed for modeling the carbon dynamics of the natural vegetation, CARAIB was already adapted for crop modeling but further modifications regarding the management, i.e., yearly-dependent sowing dates, were introduced. For grassland modeling, simulation results will be further intercompared with other modeling groups, but preliminary results showed that the model could cope with the introduction of the grass cutting module. For crop modeling, building the IRS over 30 years permitted to assess the sensitivity of the model to temperature and precipitation changes. So far, the participation of CARAIB in the intercomparison exercises within MACSUR resulted in further improvements of the model by introducing new functionalities. [less ▲]

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See detailNew alternatives to chemical pesticides: deciphering the action mechanisms of lipid based plant elicitors via complementary biophysical and biological approaches.
Nasir, Mehmet Nail ULg; Polo Lozano, Damien ULg; Luzuriaga Loaiza, Walter ULg et al

Poster (2014, February)

Nowadays, many health and environmental problems are caused by the use of chemical pesticides. In this context, an increasing demand for alternative products such as biopesticides has been observed. Among ... [more ▼]

Nowadays, many health and environmental problems are caused by the use of chemical pesticides. In this context, an increasing demand for alternative products such as biopesticides has been observed. Among biopesticides, elicitor molecules which are able to trigger immune defense responses in plants are one of the most promising options. Although numerous elicitors have been discovered, the mechanisms involved in the perception, by plants, of only a few molecules have been identified. These elicitors usually interact with proteic receptors but we have recently shown that they may also act on the lipid phase of the plasma membrane. This project first aims to improve our understanding of the molecular mechanisms involved in the recognition of specific lipid based elicitors (LBE). On that basis, the FIELD project will contribute to the design and the development of innovative compounds derived natural LBE. A multi-disciplinary approach, based on chemistry, bio-physics, bio-chemistry, and phytopathology will be followed by a consortium of different research groups from Gembloux Agro-Bio Tech in close collaboration with teams from foreign institutions. [less ▲]

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See detailAnthropogenic effects on African Landscapes: Spatial Structure, Typologies, Ecological Impact
Vranken, Isabelle ULg

Poster (2014, February)

The problematique of anthropogenic disturbance on African landscapes is studied within the double framework of DPSIR (Drivers Pressures States Impact Response) and Pattern/Process Paradygm (Landscape ... [more ▼]

The problematique of anthropogenic disturbance on African landscapes is studied within the double framework of DPSIR (Drivers Pressures States Impact Response) and Pattern/Process Paradygm (Landscape Ecology). 20 landscae images from D.R. Congo, Ivory Coast and Benin were studied using indexes of spatial (compositional and configurational) heterogeneity and anthropogenic disturbance in order to highlight the relationship between spatial structure and disturbance intensity. The results show maximal heterogeneity at intermediate anthropogenic disturbances and fasten the triangular relationship between anthropogenic effect, biodiversity and spatial heterogeneity, that had been partially theoretised with the intermidiate disturbance and habitat heterogeneity hypotheses. [less ▲]

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See detailIMPACT OF COVER CROP MANAGEMENT ON CROP PRODUCTION: A FIELD EXPERIMENT IN WALLONIA CONTEXT
Hiel, Marie-Pierre ULg; Bodson, Bernard ULg

Poster (2014, February)

Minimal soil tillage methods, crop rotation, cover crop and continuous plant residue cover are the main pillars of sustainable agriculture. Lower energy consumption, costs and time are some direct ... [more ▼]

Minimal soil tillage methods, crop rotation, cover crop and continuous plant residue cover are the main pillars of sustainable agriculture. Lower energy consumption, costs and time are some direct benefits in favor to the adaptation of this agriculture. This practices aims also directly at protecting the soil from wind and water erosion by covering the soil. Lower disruption of the soil aims at developping the micro- and macro-fauna activity that increases soil fertility and carbon and nitrogen sequestration in soils. Unfortunately, some of the great constraints to the adaptation of conservation agriculture remain weed management, fungal diseases and pest management, that has been shown to be a problem in non-ploughed fields. The aim of our study is to evaluate, on a same field (Wallonia context), contrasted tillage methods for managing the cover crop and the implantation of the main crop. The following measurements were taken: germination rate, root and shoot biomass development, root notation (size and shape), leaf area index and quality of harvested product. Preliminary results indicate that the different tillage methods did not have a significant impact on crop production or development. However changes in germination dynamics were observed, the reduced tillage inducing slower germination. Regarding weeds populations, some difference were observed in weed occurrences. Since a field exp [less ▲]

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See detailBayesian methods for predicting and modelling winter wheat biomass
Mansouri, Majdi ULg; Dumont, Benjamin ULg; Destain, Marie-France ULg

Poster (2014, February)

The objectives of this paper are threefold. The first objective is to propose to use an Improved Particle Filtering (IPF) based on minimizing Kullback-Leibler divergence for crop models' predictions. The ... [more ▼]

The objectives of this paper are threefold. The first objective is to propose to use an Improved Particle Filtering (IPF) based on minimizing Kullback-Leibler divergence for crop models' predictions. The performances of the proposed technique are compared with those of the conventional Particle Filtering (PF) for improving nonlinear crop model predictions. The main novelty of this task is to develop a Bayesian algorithm for nonlinear and non-Gaussian state and parameter estimation with better proposal distribution. The second objective is to investigate the effects of practical challenges on the performances of state estimation algorithms PF and IPF. Such practical challenges include (i) the effect of measurement noise on the estimation performances and (ii) the number of states and parameters to be estimated. The third objective is to use the state estimation techniques PF and IPF for updating prediction of nonlinear crop model in order to predict winter wheat biomass. PF and IPF are applied at a dynamic crop model with the aim to predict a state variable, namely the winter wheat biomass, and to estimate several model parameters. Furthermore, the effect of measurement noise (e.g., different signal-to-noise ratios) on the performances of PF and IPF is investigated. The results of the comparative studies show that the IPF provides a significant improvement over the PF because, unlike the PF which depends on the choice of sampling distribution used to estimate the posterior distribution, the IPF yields an optimum choice of the sampling distribution, which also accounts for the observed data. [less ▲]

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See detailImmunomodulatory effects of Rapamycin in xenogeneic GVHD
Ehx, Grégory ULg

Poster (2014, January 31)

Graft-versus-host disease (GVHD) remains a major cause of morbidity and mortality after allogeneic hematopoietic stem cell transplantation (HSCT). Several studies have shown that rapamycin (RAPA), an mTOR ... [more ▼]

Graft-versus-host disease (GVHD) remains a major cause of morbidity and mortality after allogeneic hematopoietic stem cell transplantation (HSCT). Several studies have shown that rapamycin (RAPA), an mTOR inhibitor with immunosuppressive properties, may reduce GVHD severity and mortality, notably by favoring regulatory T cells (Tregs) proliferation in vivo and in vitro. However, very few data have been reported about the global impact of this drug on the immune system in the context of GVHD. The present work investigates the cellular mechanisms by which RAPA delays death from xenogeneic GVHD induced by peripheral blood mononuclear cells infusion in NSG mice. Our results show that RAPA injections significantly delay death from xenogeneic GVHD and reduce disease severity. Flow cytometric analyses highlighted a strong reduction of human cells chimerism in mice together with higher CD4+/CD8+ T cells balance due to a lower proliferation of CD8+ T cells. In addition, the frequencies of naive CD4+ and CD8+ T cells were higher and the CD4+ T cells showed a reduced effector phenotype (CD45RO+CD27-). Tregs were positively affected as RAPA up-regulated their expression of Bcl-2 and Ki67 as well as their STAT5 phosphorylation level, leading to higher Treg frequency in treated mice. Altogether these data demonstrate that RAPA delays xenogeneic GVHD by lowering human chimerism and effector CD4+ frequency as well as promoting Tregs. [less ▲]

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See detailScikit-Learn: Machine Learning in the Python ecosystem
Joly, Arnaud ULg; Louppe, Gilles ULg

Poster (2014, January 27)

The scikit-learn project is an increasingly popular machine learning library written in Python. It is designed to be simple and efficient, useful to both experts and non-experts, and reusable in a variety ... [more ▼]

The scikit-learn project is an increasingly popular machine learning library written in Python. It is designed to be simple and efficient, useful to both experts and non-experts, and reusable in a variety of contexts. The primary aim of the project is to provide a compendium of efficient implementations of classic, well-established machine learning algorithms. Among other things, it includes classical supervised and unsupervised learning algorithms, tools for model evaluation and selection, as well as tools for data preprocessing and feature engineering. This presentation will illustrate the use of scikit-learn as a component of the larger scientific Python environment to solve complex data analysis tasks. Examples will include end-to-end workflows based on powerful and popular algorithms in the library. Among others, we will show how to use out-of-core learning with on-the-fly feature extraction to tackle very large natural language processing tasks, how to exploit an IPython cluster for distributed cross-validation, or how to build and use random forests to explore biological data. [less ▲]

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See detailL'oxydation des poudres: un défi pour l'avenir
Blecker, Christophe ULg

Poster (2014, January 27)

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See detailImmunomodulatory effects of Rapamycin in xenogeneic GVHD
Ehx, Grégory ULg; HANNON, Muriel ULg; DUBOIS, Sophie ULg et al

Poster (2014, January 27)

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See detailGIGA ANIMAL CARE : Mice & Zebrafish Animal Facility and Transgenesis
Remy, Benoît ULg; Ectors, Fabien ULg; Winandy, Marie ULg et al

Poster (2014, January 27)

In fundamental research, animal models allow to place molecular and cellular observations back into their physiological context. In applied research, these models still remain a mandatory step to evaluate ... [more ▼]

In fundamental research, animal models allow to place molecular and cellular observations back into their physiological context. In applied research, these models still remain a mandatory step to evaluate the efficiency and the toxicity of potential treatments, before going to clinical trials. Mouse and Zebrafish (Danio rerio) are two very interesting models because of a short live cycle and a high prolificacy. They require a limited space. Their genome is well known and shows a high homology with the human. Many tools are available to produce transgenic mice or zebrafishes. Many tests are validated using both these species. [less ▲]

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See detailCryopreservation of embryos : a way to reduce the number of housed animals and the genetic drift.
Remy, Benoît ULg; Ectors, Fabien ULg; Drion, Pierre ULg

Poster (2014, January 27)

The GIGA Mouse facility platform has recently improved its mouse line cryopreservation technique. The method of embryo cryopreservation by rapid cooling also called aseptic vitrification has been selected ... [more ▼]

The GIGA Mouse facility platform has recently improved its mouse line cryopreservation technique. The method of embryo cryopreservation by rapid cooling also called aseptic vitrification has been selected. Vitrification media, key steps and timing have been optimized and validated. After a first partial exposition of the embryos to cryoprotective solutions, they are immersed in a vitrifying mixture of penetrating and non-penetrating cryoprotectants for a short time. The straw containing the embryos is immediately sealed before to be plunged in LN2, resulting in a brutal solidification in which crystallization does not have time to occur. [less ▲]

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See detailKisspeptin and neuronal nitric oxide signaling are important in female sexual behavior
Hellier, Vincent ULg; Bakker, Julie

Poster (2014, January 27)

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See detailArt et schizophrénie : étude comparative de biographies d’artistes d’art brut et de sujets schizophrènes peintres
Moffarts, Aloïse; Englebert, Jérôme ULg

Poster (2014, January 22)

La psychopathologie phénoménologique explique la schizophrénie en termes de perte de l'évidence naturelle (Blankenburg, 1991/1971) ou de psychopathologie du sens commun (Stanghellini, 2000, 2004, 2007 ... [more ▼]

La psychopathologie phénoménologique explique la schizophrénie en termes de perte de l'évidence naturelle (Blankenburg, 1991/1971) ou de psychopathologie du sens commun (Stanghellini, 2000, 2004, 2007). Concernant les théories consacrées à l'art et la psychopathologie, nous nous penchons sur la théorie de la Gestaltung de Prinzhorn (1984), sur l’hypothèse de l’« l'art révolutionnaire » de Sass (1992 ; Spaniol, 2001) et analysons la classification de Jádi (Hulak, 1990). Enfin, à partir de ces travaux, nous avons établi trois types d'art qui peuvent se retrouver chez des artistes malades mentaux : art brut, art naïf et art de recherche. Notre méthodologie consiste à analyser la biographie de deux artistes peintres de la famille de « l'art brut » (Aloïse Cobraz et Adolf Wölfli) en les comparant aux biographies et analyses de cas de deux patients schizophrènes se considérant comme artistes peintres. Nous avons élaboré un questionnaire semi-structuré pour questionner les artistes sur leur parcours artistique et leur rapport à l’art. Après nos analyses et le croisement avec les théories existantes, nous émettons comme hypothèse que les schizophrènes artistes se distinguent des autres types d’artistes (pathologiques ou non) dans leur rapport à la créativité. Ceci est congruent avec le concept d’« art révolutionnaire » de Sass (1992). La classification de Jádi nous permet de suggérer qu’il n’est pas cohérent de parler d’un art des malades mentaux et que le trouble psychiatrique ne peut donc pas être considéré comme l’essence de l'art brut. Enfin, nous pouvons émettre l’hypothèse que l'art semble conférer aux schizophrènes artistes une forme d'adaptation sociale eu égard au sens commun « perdu ». [less ▲]

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See detailLe Rorschach selon le Système Intégré et le TCI-R : comparaison et intégration
Rentmeister, Daniel; Englebert, Jérôme ULg; Blavier, Adelaïde ULg

Poster (2014, January 22)

Pour cette étude, un double objectif est recherché. Premièrement, nous comparons statistiquement le test de Rorschach selon le Système Intégré de J.E.Exner et le Temperament and Character Inventory – ... [more ▼]

Pour cette étude, un double objectif est recherché. Premièrement, nous comparons statistiquement le test de Rorschach selon le Système Intégré de J.E.Exner et le Temperament and Character Inventory – Revised de R. Cloninger afin de mettre en évidence leurs divergences et convergences. Deuxièmement, à l’aide de cas cliniques, nous discutons de la pertinence de l’intégration des résultats obtenus par ces deux outils en vue d’établir le profil psychologique complet et cohérent d’un individu. Pour la comparaison statistique, notre échantillon de 27 sujets tout-venant (M = 24,37 ans ; SD = 2,75) a d’abord été soumis au test de Rorschach. Directement après, chaque sujet a complété le TCI-R. Une analyse de corrélation (Rho de Pearson) a été calculée entre les indices et un ajustement de Bonferroni a été effectué. Pour l’analyse de cas, 3 sujets cliniques ont été recrutés. Une anamnèse a été réalisée et le test de Rorschach et TCI-R administré. Nos premiers résultats, qui sont à prendre avec prudence au vu du faible nombre de sujet de l’échantillon, sont à nuancer et discuter. À partir de 2016 comparaisons statistiques, nous sélectionnons les résultats les plus pertinents et discutons des différentes corrélations observées. Les analyses de cas nous montrent une concordance au niveau des relations sociales et de l’impulsivité ; et nous montrent que les informations propres à chaque test permettent de compléter le profil du sujet. Enfin, c’est en abordant les deux épistémologies différentes sur lesquelles reposent ces deux tests que nous pouvons expliquer au mieux les différences psychologiques mises en évidence à propos des mêmes individus. Nous concluons en suggérant que cette différence de résultats doit certainement être comprise selon une logique intégrative et souligne la complémentarité existant entre ces deux épreuves. [less ▲]

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See detailLe problème des protocoles longs au test de Rorschach
Dufour, Cristelle; Englebert, Jérôme ULg

Poster (2014, January 22)

Notre étude s’intéresse aux protocoles exceptionnellement longs (supérieurs à 50 réponses) fournis par cinq sujets au test du Rorschach administré et interprété selon la méthode du Système Intégré (Exner ... [more ▼]

Notre étude s’intéresse aux protocoles exceptionnellement longs (supérieurs à 50 réponses) fournis par cinq sujets au test du Rorschach administré et interprété selon la méthode du Système Intégré (Exner, 2003). Afin de mieux comprendre quelle attitude adopter face à ce type de protocole, nous avons effectué une réduction a posteriori du nombre de réponses en nous basant sur les recommandations d’Exner (1988, 1992, 2003). Nous avons ensuite réalisé une étude comparative entre l’interprétation clinique réalisée avec la totalité des réponses et avec seulement les cinq premières réponses par planche. Nous avons également reproduit cette méthodologie de réduction a posteriori du nombre de réponses avec quatre réponses par planche en nous inspirant des nouvelles recommandations du système R-PAS de Meyer et al. (2009). Selon ces propositions, un protocole de test de Rorschach serait valide lorsque le sujet fournit entre 20 et 40 réponses (entre 2 et 4 par planche). L’échantillon est composé de trois sujets tout-venant et deux sujets psychiatriques. Notre analyse a mis en évidence une stabilité de certaines variables (EB, Lambda, EA) mais d’importantes différences dans le profil psychologique des sujets après réduction. Nous avons observé une clarification des difficultés fondamentales chez les sujets psychiatriques et plutôt une neutralisation de ces difficultés pour les sujets tout-venant, avec notamment des stratégies défensives qui apparaissent plus adaptées. Selon les résultats obtenus à partir de notre échantillon, nous pouvons suggérer que la prise en compte de la totalité des réponses ou seulement du protocole partiel induit une différence dans l’interprétation clinique. En conséquence, toute réduction du nombre de réponses devrait se faire avec grande prudence. Notre étude permet de discuter des pratiques actuelles du test de Rorschach, en faisant dialoguer les contraintes inhérentes à la validité du test et les questions de la réduction de la complexité clinique propres à toute entreprise de standardisation. [less ▲]

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See detailDendroecology and Dendroclimatology of a Tasmanian Bog Forest
Balanzategui, Daniel; Copenheaver, Carolyn; Frank, David et al

Poster (2014, January 14)

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See detailDepression and autobiographical memory: which are the characteristics of depressed patients' self-defining memories?
Wagener, Aurélie ULg; Weigend, Alicia; Boulanger, Marie ULg et al

Poster (2014, January 13)

BACKGROUND. Depressed patients suffer from autobiographical memory deficits. Indeed, depressed patients present an overgeneralization and a mood congruence biases. Moreover, they seem to have difficulties ... [more ▼]

BACKGROUND. Depressed patients suffer from autobiographical memory deficits. Indeed, depressed patients present an overgeneralization and a mood congruence biases. Moreover, they seem to have difficulties to recall positive memories. Our aim is to focus on a specific kind of memories called “self-defining memories” (SDM) which are highly pertinent for self-building. Their characteristics (e.g. specificity, meaning making) were assessed and compared to those of healthy subjects. HYPOTHESES. Depressed patients relate less specific and meaning making events than control group. A mood congruence bias is observed. METHOD. 17 depressed patients and 18 healthy subjects fulfilled SDM exercises: subjects were asked to relate six important events that happened in their life. These SDM were assessed on several variables: specificity, impact, meaning making, contain. Moreover, subjects were assessed on depression severity and self-esteem (explicit and implicit). RESULTS. No difference between depressed patients and healthy subjects has been found for specificity. A marginal effect appeared for meaning making: control group seemed to relate more meaning making events than depressed patients. Depressed patients related more negative events than control group: this negative emotional valence was positively correlated with higher depression severity. Depressed subjects presented a lower explicit self-esteem than healthy subjects but no difference has been found for implicit self-esteem. Higher explicit self-esteem was positively correlated with positive emotional valence of SDM. DISCUSSION. Results partially support our hypotheses. Experimental and clinical implications of our results will be discussed. [less ▲]

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See detailSelves Impairment in Bipolar Disorder through Self-Concept Clarity, Self-Defining Memories and Self-Esteem
Wagener, Aurélie ULg; Boulanger, Marie ULg; Van Limbergen, Coralie et al

Poster (2014, January 13)

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See detailOptimization of cricket breeding production system for human food in Ratanakiri province (Cambodia)
Caparros Megido, Rudy ULg; Alabi, Taofic ULg; Nieus, Clément et al

Poster (2014)

Despite many natural resources, Cambodia is considered as a relatively poor country with a Gross National Income per capita averaging about 880 USD in 2012. Annâdya project in the Ratanakiri province ... [more ▼]

Despite many natural resources, Cambodia is considered as a relatively poor country with a Gross National Income per capita averaging about 880 USD in 2012. Annâdya project in the Ratanakiri province (Cambodia) aims to improve the food security and nutrition of smallholder households by introducing and facilitating the adoption of productive and environmentally sustainable agricultural technologies. The main purpose of this work was to optimize a cheap cricket breeding production system for local farmers to contribute to the reduction of protein deficiency and to create new source of incomes. Cricket development, Teleogryllus testaceus (Walker), was compared between seven diets composed of different ratio of aerial parts of taro, young cassava leaves, young cashew leaves, brown rice flour (with or without the addition of banana slices) and between the traditionally used chicken feed diet. Cricket mortality was relatively low on all diets (<10 %) excepted on the two cashew-based diets where mortality achieves 90 %. Mean adult body mass of the cricket was significantly higher on control diet (chicken feed) and on the two cassava-based diet (80% of cassava leave flour, 20% of brown rice with or without banana slices) than on the other diets (F = 20.87, P<0.001). The nutritional analyzes of the seven diets shows that the ideal diet should contain 19% protein, 5-6% fat, and a percentage of carbohydrates as high as possible. While the cricket mass body gain seems to be proportional to the carbohydrate content of the diet, the use of older cassava leaves, more rich in carbohydrates than the younger ones, is an interesting solution to substitute relatively expensive brown rice and banana slices also consumed by local population. In the future, consideration should be given to the adjustment of cassava leave maturity in function of the cricket growth stage as it is already done with chicken feed in Thai cricket farms. [less ▲]

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See detailMartian thermosphere scale height from SPICAM dayglow measurements
Stiepen, Arnaud ULg; Gérard, Jean-Claude; Bougher, Steve et al

Poster (2014)

We analyze the ultraviolet dayglow in the atmosphere of Mars through CO2+ and CO Cameron emissions. These emissions are accumulated on a large dataset of dayside grazing limb performed by the Spectroscopy ... [more ▼]

We analyze the ultraviolet dayglow in the atmosphere of Mars through CO2+ and CO Cameron emissions. These emissions are accumulated on a large dataset of dayside grazing limb performed by the Spectroscopy for Investigation of Characteristics of the Atmosphere of Mars (SPICAM) instrument on board the Mars Express spacecraft. The temperature of the Martian upper atmosphere can be retrieved from these limb emission profiles. We present discussion on the validity domain for such retrieval. We also show evidence for local (spatial and temporal) variability in the scale height of the atmosphere at the altitude of these emissions. [less ▲]

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See detailSituation and perspective of entomophagy in Kinshasa
Nsevolo, Papy; Caparros Megido, Rudy ULg; Blecker, Christophe ULg et al

Poster (2014)

Eating edible insects in Republic Democratic of Congo is a tradition for centuries but a lack of knowledge remains about an actualized inventory of species consumed in the country. Moreover, a rigorous ... [more ▼]

Eating edible insects in Republic Democratic of Congo is a tradition for centuries but a lack of knowledge remains about an actualized inventory of species consumed in the country. Moreover, a rigorous taxonomic matching of the used vernacular name of edible insects and a precise characterization of the sector of entomophagy are still needed. According to our studies focused on the city of Kinshasa, 14 edible species were inventoried as regularly consumed. They belong respectively and by degree of importance to the Lepidoptera (46.7%), Isoptera (18.6%), Orthoptera (17.6%), Coleoptera (9.7%) and Hymenoptera (3.7%) orders. Generally 80.0% of the Kinshasa population consumes at least one species of insects 5 days per month. The key peoples in the edible insect sector are mostly women. The incomes generated by this activity contribute to the well being of households, to reduce poverty and food insecurity in the capital Kinshasa. Future studies should focus on sustainable ways of harvesting wild populations, the use of improved conservation practices, the enhancement of cottage industries for farming insects and the development of economically feasible ways of mass-rearing edible species. [less ▲]

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See detailEfficient method for a controlled deposition of Pd nanoparticles on a glassy carbon electrode
Olu, Pierre-Yves; Chatenet, Marian; Job, Nathalie ULg

Poster (2014)

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See detailHow can long-term experimental plots can help us to understand the sustainability of different phosphorus inputs ?
Renneson, Malorie ULg; dufey, Joseph; Roisin, Christian et al

Poster (2014)

During the last twenty years, we observed a constant reduction of mineral fertilizer use, due to prices increase and environmental awareness, and an increase of crop removal, leading to a phosphorus (P ... [more ▼]

During the last twenty years, we observed a constant reduction of mineral fertilizer use, due to prices increase and environmental awareness, and an increase of crop removal, leading to a phosphorus (P) budget decrease. These changes are feared for a decrease of soil P content, which is already observed in some regions in Wallonia. However, P being an essential element for plant growth, is a such management compatible with yield maintaining? Are the current cropping systems sustainable? To answer to the questions, different studies are made. However, long-term data are rarely available to understand the influence of cropping systems on the soil behavior, leaching risks or to choose adequate indicators of P. To answer to these questions in our soils, 2 experimental plots of the Walloon Agricultural Research Center. These experimental plots were established in 1967 and 1959 in order to evaluate the effect of, respectively, 3 P and K input levels and different organic inputs on the production. Soils samples were taken in plots and analyzed in laboratory. So, different P indicators and edaphic parameters were determined. This study showed that all indicators are coherent with P levels and correlated with yields but no many differences can be shown between fertilizer types. Meanly, zero P-input engenders a decrease of yield of 7%, while a double input increases yield of 2% in comparison to plots with an input corresponding to crop export. So, financially, the zero P-input option is rarely profitable in the long-term and double input of P removed is never financially sustainable. Leaching into deeper soils levels was studied with analysis of deeper horizons which indicated any leaching , even in plots with double inputs. Indeed, soil P contents in depth were similar in these plots than those with no P-inputs or soils under forest cover. So, to conclude, these plots help to study the sustainability of cropping systems in real situations and to determine appropriate management of P. [less ▲]

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See detailPréservation de la thymopïèse dans le grand âge
RICOUR, Céline ULg; de saint hubert, Marie; Martens, Henri ULg et al

Poster (2014)

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See detailEtude de la durabilité des hydrofuges de surface pour la conservation du patrimoine en béton
Lucquiaud, Vincent ULg; Courard, Luc ULg

Poster (2014)

La protection du patrimoine historique en béton est un challenge pour les années futures. Un traitement hydrofuge retarde l’apparition de pathologies du béton et apporte une protection contre la ... [more ▼]

La protection du patrimoine historique en béton est un challenge pour les années futures. Un traitement hydrofuge retarde l’apparition de pathologies du béton et apporte une protection contre la pénétration de l’eau. Les produits existants - essentiellement du silane et siloxane base - ont été soumis à différents processus de vieillissement, tels que la carbonatation accélérée, des rayons UV, des cycles d'humidification, des chocs thermiques, et des cycles de gel-dégel. Leur efficacité a été évaluée suivant la mesure de l’angle de contact, leur perméabilité à la vapeur d’eau et aux chlorures et leur absorption capillaire. Les résultats de l’étude montre un bon comportement de ces produits aux les principaux vieillissements étudiés. [less ▲]

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See detailEstimation of dominance variance for growth traits with sire-dam subclass effects in a crossbred population of pigs
Dufrasne, Marie ULg; Faux, Pierre ULg; Piedboeuf, Maureen et al

Poster (2014)

Nonadditive genetic effects may be not negligible but are often ignored in genetic evaluations. The most important nonadditive effect is probably dominance. Prediction of dominance effects should allow a ... [more ▼]

Nonadditive genetic effects may be not negligible but are often ignored in genetic evaluations. The most important nonadditive effect is probably dominance. Prediction of dominance effects should allow a more precise estimation of the total genetic merit, particularly in populations that use specialized sire and dam lines, and with large number of full-sibs, like pigs. Computation of the inverted dominance relationship matrix, D-1, is difficult with large datasets. But, D-1 can be replaced by the inverted sire-dam subclass relationship matrix F-1, which represents the average dominance effect of full-sibs. The aim of this study was to estimate dominance variance for longitudinal measurements of body weight (BW) in a crossbred population of pigs The dataset consisted of 20,120 BW measurements recorded between 50 and 210 d of age on 2,341 crossbred pigs (Piétrain X Landrace). A random regression model was used to estimate variance components. Fixed effects were sex and date of recording. Random effects were additive genetic, permanent environment, parental dominance and residual. Dominance variance represented 7 to 9% of the total variance and 11 to 30% of additive variance. Those results showed that dominance variance exists for growth traits in pigs and may be relatively large. The estimation of dominance effects may be useful for mate selection program to maximize genetic merit of progeny. [less ▲]

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See detailMechanoreceptors in the anterior horn of the equine medial meniscus: an immunohistochemical approach.
Nemery, Elodie ULg; Gabriel, Annick ULg; Piret, Joëlle ULg et al

Poster (2014)

Mechanoreceptors are “encapsulated sensory end-organs” involved in proprioceptive function. Given the high incidence of meniscal injuries in horses, the clinical interest in these mechanoreceptors ... [more ▼]

Mechanoreceptors are “encapsulated sensory end-organs” involved in proprioceptive function. Given the high incidence of meniscal injuries in horses, the clinical interest in these mechanoreceptors, particularly in the meniscus, and the lack of information concerning them in equine menisci, our objective was to study these corpuscles in the anterior horn of the equine medial meniscus, which is the most common localization reported for equine meniscal injuries. An immunohistochemical approach to detect Schwann cells and nerve fibres allowed us to localize and identify these corpuscles within the meniscus. Three types of mechanoreceptors were identified and localized between the abaxial quarter and the abaxial third of the meniscus: the Ruffini, Pacini and Golgi corpuscles. In conclusion, from a purely fundamental point of view, our work highlights for the first time the presence of MCR at the level of the anterior horn of the equine medial meniscus and proposes a classification based on specific immunocytochemical techniques. This morphological approach could serve as a basis for clinical studies, in order to evaluate the impact of these corpuscles on the poor sportive prognosis in equine meniscal tears. [less ▲]

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See detailULTRASONIC WAVES THROUGH AGRICULTURAL SOILS TO DETERMINE THEIR COMPACTION AND POROSITY LEVEL 
Luong, Jeanne ULg; Mercatoris, Benoît ULg; Destain, Marie-France ULg

Poster (2014)

Compaction is one of the major causes of the physical degradation of agricultural soils. The traffic of more and more heavy machines leads to a decrease of the porosity at both the topsoil and subsoil ... [more ▼]

Compaction is one of the major causes of the physical degradation of agricultural soils. The traffic of more and more heavy machines leads to a decrease of the porosity at both the topsoil and subsoil levels. This has negative impacts in agricultural and environmental contexts such as the reduction of soil fertility and water infiltration. This project aims at characterizing in a fast and non-destructive way the state of compaction of an agricultural soil at a local scale using ultrasonic wave propagation. Acoustic signatures of soil samples will be correlated to their compaction level and their porosity distribution. This should allow a better comprehension of the compaction process and help to define critical threshold. As a result, this methodology could assist in taking restrictive measures such as load limitation of agricultural engines and implementing remedial methods. This poster presents the experimental protocol implement for this research. [less ▲]

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See detailMetabolic cerebral correlates of conjunctive and relational memory in Alzheimer's disease
Bastin, Christine ULg; Bahri, Mohamed Ali ULg; Collette, Fabienne ULg et al

Poster (2014)

Introduction. Memory deficits are the clinical hallmark of typical Alzheimer’s disease. The precise nature of these deficits however remains to be fully characterized. In this study, we investigated ... [more ▼]

Introduction. Memory deficits are the clinical hallmark of typical Alzheimer’s disease. The precise nature of these deficits however remains to be fully characterized. In this study, we investigated binding in long-term episodic memory. Relational binding processes in memory create an associative link between independent items or between items and context into episodic memories (Cohen et al., 1999). An alternative process, conjunctive binding, allows associations to be encoded as a united representation of features into a single entity (O'Reilly and Rudy, 2001; Mayes et al., 2007). The current study (1) assessed whether Alzheimer’s disease disrupt both conjunctive and relational memory, and (2) related patients’ memory performance to cerebral metabolism. Methods. Thirty patients with mild Alzheimer’s disease and 24 healthy older adults performed a source memory task where items were associated to a background color (Diana et al., 2008, 2010). In one condition, relational binding was promoted by the instruction to associate the item with another object of the same color as the background. In the other condition, color had to be integrated as an item feature (conjunctive binding). Patients’ brain metabolic activity at rest (FDG-PET) was analysed with spatio-temporal Partial Least Squares (McIntosh et al., 1996) in order to assess the relation of behavioral performance and activity in functional cerebral networks. Results. Alzheimer’s disease patients had an impaired capacity to remember item-color associations, with deficits in both relational and conjunctive memory. However, performance in the two kinds of associative memory varied independently across patients. Partial least square analyses revealed a significant pattern of metabolic activity that correlated specifically with each condition (accounting for 76.48 % of the covariance in the data; p< .05). More specifically, poor conjunctive memory was related to hypometabolism in an anterior temporal-posterior fusiform brain network, whereas relational memory correlated with metabolism in regions of the default mode network. Conclusions. These findings support the hypothesis of distinct neural systems specialized in different types of associative memory and point to heterogeneous profiles of memory alteration in Alzheimer’s disease as a function of damage to the respective neural networks. [less ▲]

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See detailSpectroscopic analysis of the remorin-lipid interactions at the moleculaer level
Nasir, Mehmet Nail ULg; Perraki, Artemis; Mongrand, Sébastien et al

Poster (2014)

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See detailDoes the facultative bacteria Serratia symbiotica influence the foraging strategies of aphid parasitoids?
Attia, Sabrine; Louâpre, Philippe; Foray, Vincent et al

Poster (2014)

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See detailLignin as a raw material for industrial materials applications
Richel, Aurore ULg; Vanderghem, Caroline ULg; Jacquet, Nicolas ULg et al

Poster (2014)

Native lignin is an abundant biopolymer on earth and represents 15-30% by weight of the lignocellulosic biomass. Lignin is a heterogeneous cross-linked polymer composed of phenylpropane units (guaiacyl ... [more ▼]

Native lignin is an abundant biopolymer on earth and represents 15-30% by weight of the lignocellulosic biomass. Lignin is a heterogeneous cross-linked polymer composed of phenylpropane units (guaiacyl, syringyl or p-hydroxyphenyl) linked together by a panel of specific ether or carbon-carbon bonds.[1] Nowadays, large amounts of lignins and lignin-based wastes are available and originate either from the pulp and paper manufacturing or from the production of bioethanol from lignocellulose. [2] Typically, these lignins are dedicated to energetic purposes by combustion. In recent years however, novel axes for high added value applications have emerged and concern, notably, the use of lignin as performance products (e.g. polymer additives, binders) or specialty chemicals (e.g. surface-active agents) for materials applications.[3] Herein, several applications of lignin in materials sciences with industrial issues are presented. A correlation is established between the extraction processes from lignocellulosic materials and the chemical structure and physico-chemical properties of lignins.[4] Our research group has also developed new methodologies for the extraction of highly pure lignins from several starting materials, including food wastes, herbaceous raw materials and wood biomass. These methodologies include microwave-assisted extraction and two-step conventional pretreatment involving steam explosion. These methodologies are described in this presentation. [less ▲]

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See detailThe facultative bacterial symbiont Serratia symbiotica in Acyrtosiphon pisum confer resistance to Aphidius ervi
Attia, Sabrine; Foray, Vincent; Louâpres, Philippe et al

Poster (2014)

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See detailRelations between negative symptomatology and executive measures in schizophrenia.
Laloyaux, Julien ULg; Guettafi, Yassine; Dessart, Gregory et al

Poster (2014)

Introduction: Negative symptomatology and cognitive impairments are core features of persons diagnosed with schizophrenia that have a major negative impact on everyday life functioning. Further, some ... [more ▼]

Introduction: Negative symptomatology and cognitive impairments are core features of persons diagnosed with schizophrenia that have a major negative impact on everyday life functioning. Further, some authors (Konstantakopoulos et al., 2011) have suggested that negative symptoms and executive functions might represent different manifestations of the same syndrome, but this relation remains poorly understood. Objective: The objective was to explore relations between negative symptomatology (and in particular apathy) and executive functions in persons diagnosed with schizophrenia. Method: Twenty-seven individuals diagnosed with schizophrenia were evaluated with an extensive executive battery in addition to several measures of negative symptomatology (including specific measures of apathy) and real world functioning. Results: Results revealed that apathy was significantly related to measures of initiation (i.e. verbal fluency) and everyday life functioning. Moreover, more general measures of negative symptomatology were significantly related to multitasking abilities and cognitive flexibility. Discussion: In this study, we assessed the relations between negative symptomatology and executive measures. The results confirmed the links between these constructs, thus suggesting a common neural substrate. Conclusion: Based on results from the present study, executive dysfunctions and negative symptomatology may be seen as representing different manifestations of the same syndrome. [less ▲]

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See detailAssessing the influence of crop management strategies on the distribution of soil water content by ERT
Chelin, Marie ULg; Parvin, Nargish ULg; Hiel, Marie-Pierre ULg et al

Poster (2013, December 20)

Amongst other functions, cover crops are known to increase the stability of the soil structure. Commonly, their suppression is realized by using conventional tillage, but that it has been demonstrated to ... [more ▼]

Amongst other functions, cover crops are known to increase the stability of the soil structure. Commonly, their suppression is realized by using conventional tillage, but that it has been demonstrated to damage the soil structure, which directly impacts the soil water content. The proposed alternatives vary in terms of date, depth and type of tillage. As the soil water content is a major factor in agriculture, it is essential to better understand the influence of the cover crop management on its spatio-temporal distribution. Recent studies demonstrated the relevancy of the electrical resistivity tomography (ERT) to estimate the three-dimensional soil water content distribution. However, only a few of them were performed under field conditions. This study aims at (i) validating the use of the ERT method to estimate the soil water content distribution under field conditions (ii) quantifying the influence of cover crop management on the dynamic of soil water content along the growing season of a maize crop and on Belgian soil types. Three types of cover crop management content will be daily monitored: strip tillage, spring tillage and winter tillage. In order to assess the impact of plants on the soil water distribution, an additional plot will be burned after winter tillage. ERT will be used on a surface of 2 m² for each cover crop management. The validation of the average soil water content will be attended by using Time Domain Reflectrometers (TDR) and suction cups. The water stock obtained by ERT will be validated by using data from a weather station for the estimation of the evapotranspiration and rainfall and minirhizotrons for the assessment of the root water uptake. [less ▲]

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See detailStudy of the Bacillus subtilis ATCC21332 pbpE-racX operon in relation with the formation or disassembly of biofilms
Vanden Broeck, Arnaud ULg; Van Der Heiden, Edwige ULg; Joris, Bernard ULg et al

Poster (2013, December 20)

Bacillus subtilis is a PGPR (Plant Growth Promoting Rhizobacterium) Gram positive bacterium and a model for studying the in vitro formation or disruption of biofilms. At the liquid/air interface of ... [more ▼]

Bacillus subtilis is a PGPR (Plant Growth Promoting Rhizobacterium) Gram positive bacterium and a model for studying the in vitro formation or disruption of biofilms. At the liquid/air interface of standing cultures, B. subtilis forms thick pellicles of limited lifetimes. Some D-amino acids have been reported among the factors playing a role in the disassembly of B. subtilis biofilms and ylmE or racX mutants (in which the racemases YlmE or RacX are absent) show a delay in pellicle disruption [I. Kolodkin et al. Science (2010) 328:627-629]. The racX encoding gene is part of a bicistronic operon in which the first gene (pbpE) codes for a Penicillin-Binding Protein, the PBP4* whose function is not characterized. Our studies aim to delete the complete pbpE-racX operon and compare the phenotypes of mutants and parental strains ATCC21332 or ATCC6051 in standing cultures. The substrate specificity of the purified RacX racemase is currently under investigation as well as the functional characterization of PBP4*, a protein possessing a lipocalin-like domain. [less ▲]

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See detailImpact de l’érosion littorale dans les villes côtières africaines: de la procrastination des pouvoirs publics à la migration forcée des plus précaires. Cas de Cotonou, Bénin
Ozer, Pierre ULg; Hountondji, Yvon-Carmen; De Longueville, Florence ULg et al

Poster (2013, December 19)

Situé dans le Golfe de Guinée, le littoral béninois est soumis –sur certains tronçons– à une érosion assez rapide ces dernières décennies. Cette érosion côtière est principalement due actuellement aux ... [more ▼]

Situé dans le Golfe de Guinée, le littoral béninois est soumis –sur certains tronçons– à une érosion assez rapide ces dernières décennies. Cette érosion côtière est principalement due actuellement aux activités humaines parmi lesquelles les perturbations sédimentaires occasionnées par la construction de divers barrages dont celui de Nangbéto sur le fleuve Mono ; le blocage du transit littoral par les ouvrages portuaires de Cotonou ; les carrières de sable exploitées à même la plage ; et la diminution d’apports sédimentaires provenant de l’ouest suite à divers travaux de protection des côtes. En utilisant la fonction multi dates disponible dans Google Earth, cet article estime la superficie érodée à Cotonou entre 2002 et 2011 à l’est de l’exutoire du Lac Nokoué. En outre, il évalue le nombre de maisons détruites ainsi que le nombre de personnes contraintes à une migration forcée. Les figures sont importantes puisque de l’ordre de cent mètres de zone côtière ont totalement disparu en une décennie sur un tronçon de près de six kilomètres de long en pleine ville ou en proche périphérie. [less ▲]

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See detailLes acteurs non étatiques jouent un rôle déterminant dans le fonctionnement des services publics en territoires périurbains
Manzambi Kuwekita, Joseph ULg; Bruyère, Olivier ULg; REGINSTER, Jean-Yves ULg et al

Poster (2013, December 19)

Cette étude répertorie les acteurs étatiques et non étatiques qui offrent des services publics aux populations en territoire périurbain en vue d’améliorer leur intégration dans les politiques de ... [more ▼]

Cette étude répertorie les acteurs étatiques et non étatiques qui offrent des services publics aux populations en territoire périurbain en vue d’améliorer leur intégration dans les politiques de développement local de la commune périurbaine de Kisenso à Kinshasa, par des focus groups en juillet 2013. La question de recherche était : « quels sont les acteurs étatiques et non étatiques qui offrent les services publics en territoire périurbain, leurs rapports avec l’administration publique et comment envisager leur intégration dans les politiques de développement local » ? Les principaux résultats de cette étude montrent qu’à Kisenso, 5 acteurs étatiques et 75 acteurs non étatiques opèrent dans la commune de Kisenso, essentiellement dans les domaines suivants : santé, éducation, justice, social, environnement, énergie, PME, etc. en ce qui concerne les rapports qu’entretiennent les acteurs non étatiques avec l’Etat, (i) tous sont reconnus par la Commune car ils détiennent des autorisations délivrées par les instances de niveau national, (ii) ils ne rendent pas compte à la commune de leurs activités de manière formelle parce la loi ne les y oblige pas. 109 structures de santé sont fonctionnelles. Néanmoins, environ une trentaine d’ONGs transmettent leurs rapports d’activités à la Commune en fin d’année. De même, les acteurs non étatiques évoluant dans le secteur des soins de santé transmettent tous leurs rapports épidémiologiques, mais seulement 15/109 (soit 13,7%) rapportent sur les activités (SNIS). À la question de savoir pourquoi la population recourt aux services offerts par les différents acteurs, cette étude montre que les choix des populations pour un service ou un autre sont motivés essentiellement par la qualité de ces services, la compétence du personnel, l’efficacité, l’accueil, les coûts accessibles, l’accueil et la proximité du service avec le ménage. Quant à la manière d’intégrer les acteurs non étatiques dans les politiques de développement local, les acteurs ont proposé le processus suivant : (i) inventorier les structures et/ou les acteurs œuvrant dans la zone de santé et/ou la commune, (ii) faire les états des lieux pour identifier leur degré de fonctionnement, (iii) accorder les autorisations aux structures qui remplissent les conditions de fonctionnement, (iv) aider celles qui ne remplissent pas ces conditions à les remplir par la formation du personnel, la subvention des structures, etc.). Les résultats de cette recherche suggèrent que si l’on veut éviter que certains acteurs continuent à opérer dans la clandestinité pour des raisons d’ordre financier, à l’instar de tradipraticiens, ils devraient être exonérés de toutes taxes. Les résultats de cette recherche montrent que si l’on veut intégrer les acteurs non étatiques dans les politiques de développement local, les différentes autorités municipales devraient les associer, en amont, aux activités organisées telles la formation et la supervision, sans que cela ne leur soit facturé ; leur demander ensuite de rapporter sur leurs activités ne devrait plus entraîner de résistance. [less ▲]

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See detailContribution à l’optimisation de la localisation des zones adaptées au développement de l'agriculture périurbaine dans la commune de Parakou (Bénin) : étude des potentialités à partir des données multi sources (spatiales et socioéconomiques)
Hountondji, Yvon Carmen; De Longueville, Florence ULg; Ozer, Pierre ULg

Poster (2013, December 19)

Le présent document vise de façon globale à produire des bases techniques pour une mise en valeur rationnelle des zones adaptées au développement de l’agriculture d’appoint (produits de contre-saison) à ... [more ▼]

Le présent document vise de façon globale à produire des bases techniques pour une mise en valeur rationnelle des zones adaptées au développement de l’agriculture d’appoint (produits de contre-saison) à la périphérie de la ville de Parakou. Nous avons mis au point un outil technique pour appuyer la municipalité de Parakou (qui est en forte demande d’expertise) dans la gestion du foncier rural et urbain et à développer, autour de cette gestion foncière, des investissements à caractère économique et des actions de préservation des ressources naturelles. Sur base d’une approche systémique basée à la fois sur des données biophysiques (notamment spatiales) et socio-économiques, nous avons développé un outil de planification spatiale et d’aide à la décision pour l’ensemble des acteurs communaux investis sur la problématique du développement agricole local et de l’aménagement des espaces périurbains. [less ▲]

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See detailUn contrat de rivière en zone périurbaine, la rivière Lukaya à Kinshasa, RDC.
Rosillon, Francis ULg; Jacmain, Céline

Poster (2013, December 19)

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See detailOxygen: a critical component of critically sized defects
Carlier, Aurélie ULg; Van Gastel, Nick; Geris, Liesbet ULg et al

Poster (2013, December 19)

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See detailEtalement urbain des villes en Afrique subsaharienne et vulnérabilité croissante face au risque d’inondation : l’exemple de Nouakchott (Mauritanie)
Ozer, Pierre ULg; Ould Sidi Cheikh, Mohamed Ahmed; Ozer, André ULg

Poster (2013, December 19)

Après la sécheresse et la désertification qui ont fortement frappé la Mauritanie dans les années 1970 et 1980, la ville de Nouakchott a connu un développement démographique spectaculaire. En effet, la ... [more ▼]

Après la sécheresse et la désertification qui ont fortement frappé la Mauritanie dans les années 1970 et 1980, la ville de Nouakchott a connu un développement démographique spectaculaire. En effet, la population de la capitale mauritanienne est passée de 134 704 habitants en 1977 à 899 887 habitants recensés en mars 2013. Depuis 2000, Nouakchott voit sa population augmenter de 125 personnes par semaine ; une croissance absolue jamais atteinte par le passé. La ville s’est donc agrandie considérablement et les nouveaux arrivants ont construit leurs maisons dans des zones marginales sans aménagement préalable. Plusieurs quartiers se sont installés soit dans des zones dépressionnaires à sols salés sous forme de sebkha, soit dans des zones dunaires fortement ensablées. Sur base de l’analyse de la relation entre pluies et inondations, nous avons pu déterminer que ces dernières n’étaient plus dues à des événements pluviométriques extrêmes mais bien à un aménagement du territoire non contrôlé. [less ▲]

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See detailLes villes d’Afrique Centrale balafrées par l’érosion ravinante : inventaire cartographique et impact socio-économique à Kinshasa (RDC)
Makanzu, Fils; Moeyersons, Jan; Vandecasteele, Ine et al

Poster (2013, December 19)

Kinshasa, la plus grande ville d’Afrique Centrale, a vu sa population passer de 404173 habitants en 1957 à près de 8 millions d’habitants en 2007, soit une augmentation d’environ 20 fois en 50 ans ... [more ▼]

Kinshasa, la plus grande ville d’Afrique Centrale, a vu sa population passer de 404173 habitants en 1957 à près de 8 millions d’habitants en 2007, soit une augmentation d’environ 20 fois en 50 ans seulement. La ville s’est entre-temps agrandie, s’étalant de 94 à 443 km² au cours de la même période. A l’aide de la télédétection et d’un SIG, les ravins d’au moins 5 mètres de large ont été cartographiés à partir d’un couple stéréoscopique SPOT 2006/2007 dans la haute ville de Kinshasa. Cet inventaire a permis la détermination de 308 ravins totalisant une longueur cumulée de 95 km qui occupent une superficie de 2 km² et dont la profondeur moyenne et la largeur moyenne sont respectivement de 7 et 21 mètres. La densité de ravinement est de 0,4 km/km². Sur le plan socio-économique, on déplore la destruction d’environ 95 habitations par an, ce qui cause des pertes estimées à 1,5 million d’USD annuellement. A cela s’ajoutent des tronçons de routes coupés, la rupture des tuyaux de raccordement en eau potable, la destruction des écoles, des centres de santé et des lieux de culte, ainsi que la chute des pylônes électriques. [less ▲]

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See detailLA DÉGRADATION D’UN ÉCOSYSTÈME FORESTIER PÉRI-URBAIN : QUELS SONT LES PRINCIPAUX FILTRES À SA RÉGÉNÉRATION ?
Hick, Aurélie ULg; Tooth, Martin; Hallin, Maud et al

Poster (2013, December 19)

Au sud de la République Démocratique du Congo, dans la province du Katanga, le redéveloppement des activités minières a entrainé un développement démographique exponentiel des principales villes minières ... [more ▼]

Au sud de la République Démocratique du Congo, dans la province du Katanga, le redéveloppement des activités minières a entrainé un développement démographique exponentiel des principales villes minières. La population de Lubumbashi, capitale du Katanga, est passée en 50 ans d’environ 100 000 habitants à plus d’1 million et demi (Munyemba Kankumbi, 2010). Cette évolution démographique a accentué la pression sur la forêt claire de type Miombo par l’augmentation des prélèvements, la pression immobilière et l’agriculture de subsistance (Malaisse, 1997). Dans la zone périurbaine de Lubumbashi, les surfaces de forêts claires qui occupaient 85 % du territoire en 1956 ont été réduites à moins de 12 % en 2009 (Munyemba Kankumbi, 2010). Trois études ont été menées dans le but de caractériser les filtres écologiques et les filtres sociaux à la restauration de cet écosystème périurbaine. Les deux premières études ont pour objectif d’illustrer la diversité des communautés végétales du Miombo, leurs variations après dégradation le long d’un gradient forêt/savane sur les sols principaux de la plaine et les principaux filtres écologiques à sa régénération. 134 placettes forestières placées aléatoirement dans les derniers massifs forestiers présents dans un rayon de 50km autour de la ville ont été inventoriées. 53 placettes ont été placées sur trois sites choisis pour caractériser les communautés présentes le long du gradient de dégradation : forêts, forêts dégradées, savanes boisées, savanes arborées et savanes herbeuses. Au sein de ces placettes l’ensemble des espèces forestières ont été identifiées. Le sol a été caractérisé physiquement et chimiquement. La mesure de la biomasse herbacée a également été réalisée sur le gradient de dégradation. Les filtres sociaux ont été analysés aux travers de 35 enquêtes menées dans 4 villages de la plaine afin de comprendre leur mode d’agriculture, leur vision de l’arbre et la possibilité d’insérer un mode de culture de type agroforestier. Les grandes communautés caractéristiques de cet écosystème ont été mises en évidence, illustrant ainsi la richesse des dernières taches forestières présentes dans la plaine. Le type de sol est significativement corrélé à la répartition des communautés. Les essences présentes en savanes sont différentes de celles présentes en forêts pour un même type de sol. La biomasse herbacée est un filtre significatif à la régénération de la forêt favorisant la présence d’espèces tolérantes au feu. La modification des conditions chimiques du sol suite à la production de charbon de bois / agriculture n’est pas apparue comme un filtre majeur de la restauration. Les enquêtes nous ont permis de recenser une liste d’espèces utiles pour la production de charbon de bois, de bois de construction, etc d’après la vision des villageois. Néanmoins, les pratiques villageoises actuelles ne montrent pas d’intérêt à la préservation de ces espèces. Leur système de culture et leurs connaissances semblent tournés vers un mode culture de plus en plus intensif, mono-spécifique et tourné vers l’utilisation de fertilisants. Le problème majeur d’accès à la ressource en bois ne semble pas être dans la conscience de la population alors que la déforestation ne cesse de croitre. [less ▲]

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See detailExpansion urbaine et risques hydrologiques : cas de Butembo (RDC)
Sahani, Muhindo; Moeyersons, Jan; Ozer, Pierre ULg

Poster (2013, December 19)

Butembo constitue un cas typique de zone urbaine en région tropicale humide rencontrant une explosion démographique exceptionnelle. L’exode vers Butembo pour fuir l’insécurité dans la sous-région a ... [more ▼]

Butembo constitue un cas typique de zone urbaine en région tropicale humide rencontrant une explosion démographique exceptionnelle. L’exode vers Butembo pour fuir l’insécurité dans la sous-région a conduit à une rapide concentration spontanée des populations et à une urbanisation sans cesse croissante. L’imperméabilisation des vastes étendues de terres consécutive à cette expansion spatiale rapide de la ville a généré des problèmes environnementaux qui affectent la structure urbaine. A l’instar de nombreuses villes d’Afrique centrale, Butembo est actuellement confrontée à des risques hydrologiques diversifiés : ravinements progressifs et régressifs, inondations, et remobilisation d’anciens glissements de terrain. [less ▲]

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See detailLE TRANSPORT SOLIDE DANS L’OUED EL-HACHEM ET SES EFFETS SUR LA RECHARGE DE LA NAPPE À PARTIR DES LACHERS DU BARRAGE DE BOUKOURDANE (Nord de l’Algérie)
Tadrist, Nassima ULg; Debauche, Olivier ULg

Poster (2013, December 18)

L’érosion hydrique et l’envasement des retenues des barrages en Algérie qui atteint des volumes élevés, causée par le transport solide (en suspension et par charriage) dans l'oued El-Hachem.L’étude ... [more ▼]

L’érosion hydrique et l’envasement des retenues des barrages en Algérie qui atteint des volumes élevés, causée par le transport solide (en suspension et par charriage) dans l'oued El-Hachem.L’étude consiste à étudier le transport de sédiments avant et après la réalisation du barrage de Boukourdane de façon à mettre en évidence la gravité de ce processus d’envasement sur la réduction du réservoir du barrage et sur l’hydraulique de l’oued à l’aval de l’ouvrage. Les résultats obtenus, montrent que le transport solide dans l’oued El-Hachem est relativement faible ; par conséquent la vitesse de sédimentation est lente dans la retenue. Cela se répercute sur la concentration dans les lâchers d’eau qui opèrent périodiquement par la vanne de fond du barrage qui devient très faible. Cette dernière n’a pas donc d’effet sur le colmatage du fond alluvionnaire de l’oued. L’étude de la recharge de la nappe à l’aval du barrage par ces lâchers confirme ce résultat. [less ▲]

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