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Bouzelboudjen, Mahmoud

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Bouzelboudjen, Mahmoud
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https://libra.unine.ch/handle/123456789/1079

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  • Publication
    Accès libre
    Serological signature of tick-borne pathogens in Scandinavian brown bears over two decades
    (2015-7-28)
    Paillard, Lye 
    ;
    Jones, Krista L.
    ;
    Evans, Alina L.
    ;
    Jacquet, Maxime 
    ;
    Berret, Jérémy 
    ;
    Lienhard, Reto
    ;
    Bouzelboudjen, Mahmoud 
    ;
    Arnemo, Jon M.
    ;
    Swenson, Jon E.
    ;
    Voordouw, Maarten 
    Background: Anthropogenic disturbances are changing the geographic distribution of ticks and tick-borne diseases. Over the last few decades, the tick Ixodes ricinus has expanded its range and abundance considerably in northern Europe. Concurrently, the incidence of tick-borne diseases, such as Lyme borreliosis and tick-borne encephalitis, has increased in the human populations of the Scandinavian countries. Methods: Wildlife populations can serve as sentinels for changes in the distribution of tick-borne diseases. We used serum samples from a long-term study on the Scandinavian brown bear, Ursus arctos, and standard immunological methods to test whether exposure to Borrelia burgdorferi sensu lato, the causative agent of Lyme borreliosis, and tick-borne encephalitis virus (TBEV) had increased over time. Bears had been sampled over a period of 18 years (1995-2012) from a southern area, where Ixodes ricinus ticks are present, and a northern area where ticks are uncommon or absent. Results: Bears had high levels of IgG antibodies against B. burgdorferi sensu lato but not TBEV. Bears at the southern area had higher values of anti-Borrelia IgG antibodies than bears at the northern area. Over the duration of the study, the value of anti-Borrelia IgG antibodies increased in the southern area but not the northern area. Anti-Borrelia IgG antibodies increased with the age of the bear but declined in the oldest age classes. Conclusions: Our study is consistent with the view that ticks and tick-borne pathogens are expanding their abundance and prevalence in Scandinavia. Long-term serological monitoring of large mammals can provide insight into how anthropogenic disturbances are changing the distribution of ticks and tick-borne diseases.
  • Publication
    Métadonnées seulement
  • Publication
    Accès libre
    3-D groundwater modeling at regional scale
    (2001)
    Kimmeier, Francesco
    ;
    Bouzelboudjen, Mahmoud 
    ;
    Király, László
    Large hydrogeological basins are constituted of several superimposed aquifers, separated by geological formations of relatively low permeabilities. The delimitation of the different flow systems is far more difficult to realize for a heterogeneous system. Flux vectors provide valuable indications about groundwater flow paths and hydraulic exchanges between the different geological formations. Hydraulic relationships between two superimposed aquifers can vary locally: an aquifer can «feed» the underlying one at some point and conversely elsewhere. These relationships, which constitute in fact the flow field, will be determined by the structure of the basin as defined by the spatial distribution of the rock permeabilities, and by the boundary conditions, as defined by the locations of the recharge and discharge areas. The aim of this study is to show schematically the deep groundwater flow patterns between the massives of the Aar and the Black Forest. The hydrogeological profiles illustrate three-dimensional flow fields inside a large volume of terrain and represent but one of the numerous solutions of the mathematical modelling realized. Computations have been performed for a steady state flow regime, which means that the boundary conditions do not vary with time.
    On the basis of modelling results, it was possible to illustrate schematically the deep flow systems of the most important aquifers between the Aar massives and the Black Forest (Malm, Muschelkalk and upper Cristallin). An approximate but plausible representation of the groundwater circulation in deep aquifers was obtained thanks to the model. We are able to distinguish between the hydraulic relationships of two superimposed aquifers in various regions. The three-dimensional representation shows the outcrop zones of the different geological formations as well as the situation of recharge areas, which are characterised by high potentials, and discharge zones, which are characterised by low potentials in valleys represented by the hydrographic network.
    Modelling results are then compared to available measurements in an attempt to validate the results. It is interesting to notice that it was possible, to a certain extent, to verify the modelling results by deep drillings. Most particularly, measurements of the hydraulic potentials at various depths in these boreholes have revealed upwellings close to the regional discharge areas.
  • Publication
    Métadonnées seulement
    Impact des changements climatiques sur le comportement des systèmes aquifères
    (Hochschulverlag AG an der ETH Zürich, 1997)
    Bouzelboudjen, Mahmoud 
    ;
    Kimmeier, Francesco
    ;
    Rossier, Yvan
    ;
    Eisenlohr, Laurent
    ;
    Kilary, Laszlo
    ;
    Zwahlen, François 
  • Publication
    Métadonnées seulement
  • Publication
    Accès libre
    TracES/View - Traçage des Eaux Souterraines : Application SIG en milieu karstique jurassien (Suisse)
    Bouzelboudjen, Mahmoud 
    ;
    Ornstein, Pascal
    ;
    Kimmeier, Francesco
    L'usage de traceurs artificiels est une méthode spécialement bien établie pour étudier les aquifères karstiques. Dans ce contexte, les traçages (avec des traceurs artificiels et biologiques) permettent de déterminer les limites des bassins versants, d'identifier la relation entre une perte et une résurgence, d'évaluer les phénomènes de diffluence, de déterminer le temps de transit, etc. Plus récemment les méthodes de traçage sont utilisées dans les études quantitatives de transport de polluant. Les essais de traçage prenant du temps et étant coûteux, une application (TracES/View) combinant les Systèmes d'Informations Géographiques (SIG) ArcInfo et ArcView, les deux couplés avec une base de données MS Access a été développée afin de planifier de façon efficace la réalisation de nouveaux essais de traçage. Une application utilisant ArcView, développée avec le language de programmation orienté-objets Avenue permet à des non-spécialistes en SIG d'accéder facilement aux éléments de la base de données des essais de traçage d'une manière graphique intuitive et interactive à l'écran. Utilisée conjointement avec d'autres cartes thématiques (la topographie, les surfaces structurales des formations géologiques, la délimitation des aquifères, les perméabilités, l'utilisation du sol, etc.), elle peut fournir un outil puissant d'aide à la décision pour la gestion des ressources en eaux souterraines., The use of artificial tracers is a specially well-established method to investigate karstic aquifers. In this case, tracing (artificial and biological tracers) enables to delimit watercatchment boundaries, to identify relation between a sinkhole and an outlet, to assess diffluent phenomena, transit time, etc. More recently tracer methods have been used in pollution transport studies. Tracer studies being time-consuming and expensive, an application (TracES/View) combining ArcInfo and ArcView Geographical Information Systems (GIS), both coupled with MSAccess database has been developped to provide an efficient way to plan the implementation and the planning of new tracer tests. An ArcView application developped with Avenue object-oriented scripting language allows GIS non-specialists to easily access data from tracer tests database in an interactive and intuitive way. Used in conjunction with other thematic maps (hydraulic conductivity, landuse, groundwater resources, and so on), it can provide a powerful decision-support tool for groundwater resources management.
  • Publication
    Accès libre
    Geohydrological parameters identification and groundwater vulnerability to pollution: A Swiss case study
    Kimmeier, Francesco
    ;
    Bouzelboudjen, Mahmoud 
    ;
    Ornstein, Pascal
    ;
    Weber, Isabelle
    ;
    Rouiller, Jean-Daniel
    The alluvial aquifer of the Rhône valley in Switzerland, which extends over 110 km and occupies an area of 256 km2, is of great economic importance. Its groundwaters are easily accessible and thus exploitable at low cost. However, its location in an often narrow valley with intense human activity (industry, agriculture, communications network) makes it particularly vulnerable from both a qualitative (industrial and\or agricultural pollution) and quantitative point of view (groundwater flow disturbance following civil engineering works). Since 1995, the Swiss canton of Valais has decided to compile datasets from a number of local studies (water supply, hydro-electricity, and geotechnical studies) into a regional, integrated hydrogeological framework. The realization of the study has shown the importance of GIS tool either for the computing and mapping of the first piezometric map between Brig and Léman Lake or the elaboration of vulnerability maps. The geostatistic tool was also intensively used all over the spatial treatment of data. The comparison of groundwaters NO3-- content (1985 and 1995), has shown that globally the nitrates content in the groundwater is low (< 30 mg/l for 90 % of samples). However it must be notice that the evolution of the NO3-- content degrades during time. The study of vulnerability to pollution for the aquifer situated between Sierre and Vétroz as shown significant differences between the four different methods used. As main results DRASTIC and SINTACS integrated methods are concentrated between Moderate and High vulnerability when NLFB and GOD intrinsic methods are concentrated between Very Low and Moderate vulnerability. Intrinsic methods have the tendency to minimize the vulnerability.
  • Publication
    Accès libre
    A statistical time series analysis of hydro-climatic stress on karst aquifer system (Switzerland)
    Kimmeier, Francesco
    ;
    Bouzelboudjen, Mahmoud 
    ;
    Eisenlohr, Laurent
    ;
    Rossier, Yvan
    ;
    Zwahlen, François 
    In order to determine the impact of climatic variations on several spring discharge, five karst aquifer systems were chosen in the Neuchâtel Jura (three basins over an area of 359 km2) and in the Prealps (2 basins of 4 and 10 km2 respectively). The records of air temperature, precipitation and groundwater discharge vary between 13 and 91 years. Statistical trend analyses (Kendall and Spearman tests) and correlation and spectral analyses have been used to analyze these records. The aim of this paper is not to generalize the results to all karstic aquifers in Switzerland but to answer the three following questions : (i) is there a trend at a given station for given parameters ?, (ii) are the trends the same for the different stations ?, (iii) and finally can we detect the impact of possible climatic changes on the natural responses of five karst springs in the Jura and Prealps ? For the Neuchâtel Jura, a regional trend of rising air temperature has been demonstrated. This is marked by two successive increases in 1945 and 1980. In the Prealps of Vaud, this trend is less well defined. Only the increase in the 1980's has been locally detected. The statistical study of precipitation shows its random character at the regional scale of the Neuchâtel Jura and Prealps. The trend of a reduction in groundwater discharge at Champs-du-Moulin in the Areuse basin is visible since 1945. It is part of a regional trend towards lower discharge, no trend has been observed at the La Doux and Noiraigue Springs. In the Prealps, a rising trend has been observed at Les Avants Spring since 1976 and a falling trend in discharge can be identified at Grandchamp Spring since 1988. Despite the fact that in certain cases, there has been a coincidence between the beginning of temperature increase and of falling discharge, the trends shown do not allow us to state that the only cause is that of climatic changes.