Université de Neuchâtel

Groundwater dynamics and streamflow generation in a mountainous headwater catchment : process understanding from field experiments and modeling studies

Freyberg, Jana von ; Schirmer, Mario (Dir.) ; Hunkeler, Daniel (Codir.)

Thèse de doctorat : Université de Neuchâtel, 2015.

Groundwater systems in mountainous headwater catchments significantly sustain downstream freshwater bodies and therefore play an important role in the regional water cycle. Complex interactions between atmospheric, subsurface and ecological variables occur that determine groundwater quantity and quality as well as streamflow-generation mechanisms at different spatiotemporal scales. An integrated...

Université de Neuchâtel

Développement d'un micro-préconcentrateur pour la détection de substances chimiques à l'état de trace en phase gaz

Camara, El Hadji Malick ; De Rooij, Nicolaas-F. (Dir.)

Thèse de doctorat : Université de Neuchâtel, 2009 ; Th. 2127.

In the field of gas detection, one major trend is to miniaturize analytical techniques. In such technological developments, the gas pre-conditioning is usually very important. This may involve, firstly, the modification of a gas mixture, for example to improve the selectivity of a detection device, secondly, the effect of preconcentration in order to increase the sensibility of the detector....

Université de Neuchâtel

Biogeochemical changes during the Cenomanian-Turonian Oceanic Anoxic Event (OAE 2)

Mort, Haydon ; Adatte, Thierry (Dir.)

Thèse de doctorat : Université de Neuchâtel, 2006 ; 1933.

Understanding how nutrients behave during sub-oxic environments is crucial in predicting future changes in the ocean-climate system. This study focuses on the role of phosphorus, in its different sedimentary reservoirs, during the Cenomanian-Turonian anoxic event (OAE 2), which occurred during the late Cretaceous (~93.5 Ma). In the geological record this period in the Earth’s history is...

Université de Neuchâtel

Modelisation de la relation entre pluie pollinique actuelle, végétation et pratiques pastorales en moyenne montagne (Pyrénées et Jura) : application pour l'interprétation des données polliniques fossiles

Mazier, Florence ; Buttler, A (Dir.)

Thèse de doctorat : Université de Neuchâtel, 2006 ; 1912.

The reliability of pollen analysis as a tool for the reconstruction of past vegetation and landscape depends on our knowledge of modern ecosystems. These reconstructions involve precise understanding of modern plant communities and how they are reflected in pollen assemblages. The calibration between present pollen deposition and vegetation has been studied with two approaches in pastoral areas...

Université de Genève

Modélisation de la démographie des populations humaines préhistoriques à l'aide de données environnementales et génétiques

Ray, Nicolas ; Excoffier, Laurent (Dir.) ; Langaney, André (Codir.)

Thèse de doctorat : Université de Genève, 2003 ; Sc. 3448.

Ce travail présente une méthodologie permettant de modéliser la diversité génétique humaine de plusieurs échantillons de populations, en prenant en compte l'environnement de l'Ancien Monde (végétation présente et passée, relief, réseau hydrographique et contours côtiers) et la démographie des 120'000 dernières années. L'environnement a été traduit en terme de capacités de...

Université de Neuchâtel

A conceptual model of flow and transport in a karst aquifer based on spatial and temporal variations of natural tracers

Perrin, Jérôme ; Zwahlen, François (Dir.) ; Jeannin, Pierre-Yves (Codir.)

Thèse de doctorat : Université de Neuchâtel : 2003 ; 1699.

Karst aquifers represent an important groundwater resource world-wide. They are highly vulnerable to contamination due to fast transport through the system and limited attenuation of contaminants. The two main hydrogeological approaches developed for studying flow and transport are: inference of the system structure from karst spring hydrographs and chemographs; numerical modelling of flow and...

Université de Neuchâtel

Geometry and hydraulic parameters of karst aquifers : a hydrodynamic modeling approach

Kovács, Attila ; Perrochet, Pierre (Dir.) ; Jeannin, Pierre-Yves (Codir.)

Thèse de doctorat : Université de Neuchâtel : 2003 ; 1724.

This thesis presents a method for characterizing flow systems in karst aquifers by acquiring quantitative information about the geometric and hydraulic parameters of a karst conduit network from spring hydrograph analysis. The investigation method applied consisted of constructing simple conceptual models of karst systems, and deducing analytical formulae describing the connection between aquifer...