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See detailLa géodésie spatiale à l'Observatoire Royal de Belgique
Warnant, René ULg; Bruyninx, Carine

in Nouvelles de la Science et des Technologies (1995), 13(2/3/4), 29-31

Detailed reference viewed: 11 (0 ULg)
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See detailGeodetic and cartographical standards applied in Belgium
Donnay, Jean-Paul ULg; Lambot, Philippe

in Van Hecke, Etienne (Ed.) A Concise Geography of Belgium (2012)

Definition of datum BD72 and GRS 80, and cartographic systems Belgian Lambert 1972 & Belgian Lambert 2008, now in use in Belgium

Detailed reference viewed: 43 (3 ULg)
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See detailGeoelectrical investigations (DC) on a contaminated site during biostimulation: monitoring results and resolution analysis
Caterina, David ULg; Nguyen, Frédéric ULg

Conference (2012, January 12)

In Belgium, as in many other countries, relatively anarchic economical and industrial development of the past century has resulted in a significant number of contaminated sites. When one of these sites ... [more ▼]

In Belgium, as in many other countries, relatively anarchic economical and industrial development of the past century has resulted in a significant number of contaminated sites. When one of these sites poses a risk to human or ecosystem, measures need to be taken to clean it up. Among these measures, methods using in situ bioremediation are beginning to become more important because of their ease of implementation and their relatively low cost. However, it is often difficult to ensure their effectiveness except by carrying out extensive drilling and sampling, which can be long and expensive while offering only punctual information. Thus, it becomes necessary to use other techniques to overcome these shortcomings. Recently, an increasing interest is being born to use geophysical methods as tools for remediation monitoring. As part of our work, we conducted several electrical resistivity tomography campaigns on a bus station located in Bassenge (Belgium) which has undergone a contamination of hydrocarbons (gasoline) for several years and on which a biostimulation remediation device was set up in order to clean it up. The aim of our investigations was to study the electrical response of the contaminated area during the remediation phase and whether electrical resistivity tomography allowed to monitor its effectiveness. After a year of monitoring, the time lapse images obtained show a significant decrease of electrical resistivities (up to -40%) during biostimulation at the location of the main contaminant plume and an increase again of resistivities from the time the biostimulation was stopped. The electrical response during the biostimulation is in agreement with the models presented by several authors in the literature. The increase again of resistivities after the stimulation is however more surprising and can be explained by several physico-chemical (sorption-desorption processes) or biological (decrease of conductive biofilms) assumptions. The results obtained tend to suggest that it is possible to use electrical resistivity tomography as a tool for qualitative control during the remediation of a contaminated site. However, for a more quantitative use of resistivity models, it is important to assess their reliability through the use of resolution indicators. We therefore developed a methodology to address this issue based on the creation of synthetic models representing simplified cases of field resistivities and we applied it on our case study. The results obtained provided us important information about the reliable parts of the resistivity models. These findings may lead in the future to the development of mathematical models that can link quantitatively geophysical properties to the level of (de)contamination of a site. [less ▲]

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See detailGeoelectrical monitoring on a contaminated site during biostimulation
Caterina, David ULg; Nguyen, Frédéric ULg

Poster (2011, December 01)

In Belgium, as in many other countries, relatively anarchic economical and industrial development of the past century has resulted in a significant number of contaminated sites. When one of these sites ... [more ▼]

In Belgium, as in many other countries, relatively anarchic economical and industrial development of the past century has resulted in a significant number of contaminated sites. When one of these sites poses a risk to human or ecosystem, measures need to be taken to clean it up. Among these measures, methods using in situ bioremediation are beginning to become more important because of their ease of implementation and their relatively low cost. However, it is often difficult to ensure their effectiveness except by carrying out extensive drilling and sampling, which can be long and expensive while offering only punctual information. Thus it becomes necessary to use other techniques to overcome these shortcomings. Recently, an increasing interest is being born to use geophysical methods as tools for remediation monitoring. As part of our work, we conducted several electrical resistivity tomography campaigns on a site contaminated by LNAPLs (gasoline) on which a biostimulation remediation device was set up. The aim of our investigations was to study the electrical response of the contaminated area during the remediation phase and whether electrical resistivity tomography allowed to monitor its effectiveness. After a year of monitoring, the time lapse images obtained show a significant decrease of the electrical resistivity (up to -50%) at the location of the main contaminant plume. This particular response during the biostimulation, in agreement with the models presented by several authors in the literature, tends to suggest that it is possible to use electrical resistivity tomography as a tool for qualitative control during the remediation. These findings may also lead in the future to the development of models to estimate more quantitatively the level of (de)contamination of a site. [less ▲]

Detailed reference viewed: 56 (14 ULg)
See detailGeografia, storia e poetiche del fantastico.
Moreno, Paola ULg

in Revue Belge de Philologie et d'Histoire (1997)

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See detailUn géographe en campagne : voir, connaître, représenter et comprendre.
Chevigne, Claire; Schmitz, Serge ULg; Tresegnie, Jean Pierre

in Donnay, Jean-Paul (Ed.) Recherches de géographie humaine, Hommage au Professeur Charles Christians. (1996)

Detailed reference viewed: 30 (4 ULg)
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See detailGeographic and genetic variation of olfactory communication in butterflies: the male sex pheromone of Bicyclus butterfly species
Bacquet, Paul; Brattström, O.; Wang, H. L. et al

in Abstract book (2010, December 17)

Detailed reference viewed: 32 (2 ULg)
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See detailGeographic ecology of soil oribatid mites in deciduous forests
Wauthy, G.; Noti, M.-I.; Dufrêne, Marc ULg

in Pedobiologia (1989), 33(6), 399-416

On a broad, geographic scale (Belgium), soil oribatid mites show relatively simple patterns of spatial distribution and habitat use since 2 groups of species can be defined: "regionally specialist' (RS ... [more ▼]

On a broad, geographic scale (Belgium), soil oribatid mites show relatively simple patterns of spatial distribution and habitat use since 2 groups of species can be defined: "regionally specialist' (RS) species which are rare and restrict their humus type occupancy, and "regionally generalist' (RG) species with reverse attributes. In the locality studied, 7/31 RS species inhabited all or nearly all the stands sampled and used widely disjunctive categories of habitat resources taking into account vertical location within organic layers (litter or humus), humus type (mor or moder) and vegetation (climax or secondary) developed in the study site. Nevertheless, their overlap on these categories was lower on average than the one of the 20 RG species which did not change their patterns on both geographic scales. Some of the 34 other RG species narrowed their local distribution and showed a clear specialization on the habitat categories. To explain the local/regional variations of patterns, it is proposed to interpret the regional distribution shown by soil oribatid mites in terms of tolerance to environmental factors. Then, it is advocated, the role of biotic interactions in the local widening of habitat breadth shown by the RS as well as RG species, and to produce a local non-equilibrium assemblage. -from Authors [less ▲]

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See detailGeographic structure and potential ecological factors in Belgium
Dufrêne, Marc ULg; Legendre, P.

in Journal of Biogeography (1991), 18(3), 257-266

The available potential ecological factors have been scored in the form of presence/absence in Universal Transverse Mercator (UTM) squares in Belgium. A correspondence analysis shows a strong underlying ... [more ▼]

The available potential ecological factors have been scored in the form of presence/absence in Universal Transverse Mercator (UTM) squares in Belgium. A correspondence analysis shows a strong underlying gradient in the data set which induces an extraordinary horseshoe effect. This gradient follows closely the altitude component. Applying the k-means clustering method on UTM squares produced geographically compact groups which are largely hierarchically nested. This indicates strong regional trends in the ecological data set. As homogeneous groups may also be artefacts created by the clustering algorithms on a continuous gradient, the relevance of the borders between homogeneous areas is tested. In general, k-means borders correspond to the main breaking lines between adjacent UTM squares. They can be referred to as natural borders. -Authors [less ▲]

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See detailGeographical allozymes differentiation in wild Phaseolus lunatus L. and its implication for conservation and management of populations
Zoro Bi, I.; Baudoin, Jean-Pierre ULg

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2007), 11(4), 287-297

Detailed reference viewed: 8 (2 ULg)
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See detailGeographical research in Belgium : remote sensing and photo-interpretation
Donnay, Jean-Paul ULg; Wilmet, Jules

in Bulletin de la Société Belge d'Etudes Géographiques (1995), 2

Detailed reference viewed: 11 (1 ULg)
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See detailThe geographical societies of Brussels and Antwerp, and their focus on Africa in the period preceding the Berlin Conference (1876-1885)
Vandersmissen, Jan ULg

in Van Schuylenbergh, Patricia; Lanneau, Catherine; Plasman, Pierre-Luc (Eds.) L'Afrique belge aux XIXe et XXe siècles. Nouvelles recherches et perspectives en histoire coloniale. (2014)

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See detailGeographical traceabilitiy of food products.
Tychon, Bernard ULg; Oger, Robert ULg

Conference (2003, March)

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See detailGeographical variation in sound production in the anemonefish Amphiprion akallopisos
Parmentier, Eric ULg; Lagardere, J. P.; Vandewalle, Pierre ULg et al

in Proceedings of the Royal Society B-Biological Sciences (2005), 272(1573), 1697-1703

Because of pelagic-larval dispersal, coral-reef fishes are distributed widely with minimal genetic differentiation between populations. Amphiprion akallopisos, a clownfish that uses sound production to ... [more ▼]

Because of pelagic-larval dispersal, coral-reef fishes are distributed widely with minimal genetic differentiation between populations. Amphiprion akallopisos, a clownfish that uses sound production to defend its anemone territory, has a wide but disjunct distribution in the Indian Ocean. We compared sounds produced by these fishes from populations in Madagascar and Indonesia, a distance of 6500 km. Differentiation of agonistic calls into distinct types indicates a complexity not previously recorded in fishes' acoustic communication. Moreover, various acoustic parameters, including peak frequency, pulse duration, number of peaks per pulse, differed between the two populations. The geographic comparison is the first to demonstrate 'dialects' in a marine fish species, and these differences in sound parameters suggest genetic divergence between these two populations. These results highlight the possible approach for investigating the role of sounds in fish behaviour in reproductive divergence and speciation. [less ▲]

Detailed reference viewed: 22 (4 ULg)