L'ensemble des interactions entre particules est à ce jour décrit dans un modèle appelé Modèle Standard. Celui-ci sera brièvement décrit dans le premier chapitre de ce manuscrit. Cependant, il apparait que ce n'est pas un modèle complet capable de tout expliquer ce que l'on observe à l'échelle de l'infiniment petit et d'unifier l'ensemble des couplages à grande énergie. C'est pourquoi de nombreuses théories ont vu le jour, avec plus ou moins de succès, dans l'espoir d'avoir une théorie du "tout". Parmis ces modèles, beaucoup prédisent l'existence de particules ayant certaines propriétés, on les appelle Leptoquarks. <br />Ce manuscrit présente une analyse pour la recherche de telles particules aboutissant finalement non pas a une decouverte mais a une limite d'existence en fonction de leur masse. Cette analyse a été effectuée à partir de données collectées auprès du détecteur D0 situé à un des points autour de l'accélérateur TeVatron à Fermilab, près de Chicago. Le cadre expérimental de cette expérience sera décrit dans le second chapitre. Ce manuscrit présente également la contribution que j'ai eu auprès de la collaboration de D0 pour la calibration du calorimètre électromagnétique.

<p>This paper examines the prevalence and character of age discrimination by conducting and experiment with 200 students at Växjö University. The participants were first asked to read a description of a job of either youthful or age neutral character. Afterwards they got to evaluate one out of two job applicants. The applicants were made identical in every way with the exception of age, in order to isolate the age discrimination. The results for the different jobs and applicants were then compared in order to investigate the prevalence of discrimination. The results support the hypothesis that age discrimination exists. In order to examine the dominance of either taste discrimination or statistical discrimination, i.e. whether the discrimination is the result of personal preferences or stereotypes and statistical mean values of different age groups the results were studied more in depth. The results hint a dominance of statistical discrimination over taste discrimination.</p>

Thesis (Ph. D.)--Swedish University of Agricultural Sciences, 2000. / Includes bibliographical references (p. 393-402) and index.

Thesis (M.S.)--Florida State University, 2003. / Advisor: Dr. James R. Simpson, Florida State University, College of Engineering, Dept. of Industrial and Manufacturing Engineering. Title and description from dissertation home page (viewed Mar. 2, 2004). Includes bibliographical references.

Increasing atmospheric carbon dioxide (CO₂) leads to global warming. This can have several impacts on climate and on plant biodiversity, and has been the topic of many studies. The objective of this thesis was to understand the effects of higher atmospheric CO₂ on soil moisture dynamics in the grasslands of central Minnesota using detailed hydrologic modeling to explain previous experimental observations at the BioCON site, a free-air CO₂ enrichment experiment. The hydraulic properties and texture of soils collected from BioCON were determined in the laboratory through grainsize analysis and continuous evaporative drying to determine soil moisture retention curves and hydraulic conductivities. These results were used as input for numerical soil water flow and energy balance models. The models showed that vegetation presence and atmospheric CO₂ concentrations significantly affected the soil moisture dynamics. Summer evapotranspiration (ET) had a higher variation for bare plots than for vegetated plots. This likely occurred because the vegetation provided a buffer against the variations in weather conditions. Vegetation not only retains part of the precipitation on its leaves, it also retains water in its structure and transpires while carrying out photosynthesis. Higher water content was also seen for the bare plots than for the vegetated soils. For some vegetated plots, there were differences between simulated and observed soil moisture. This could have been caused by a difference in plant composition and could suggest that different plant species can respond differently to varying CO₂ atmospheric concentrations leading to different soil moisture dynamics. In addition to this, smaller ET values and higher soil water content values at vegetated elevated CO₂ conditions than at ambient CO₂ conditions were simulated. This was expected, as higher atmospheric CO₂ is linked to higher plant water efficiency and larger biomass. For the simulations, higher values for stomatal resistance and higher plant and plant residue biomass were used. If increasing CO₂ conditions in fact decreases ET, regional weather patterns could be affected as less ET could delay the speed that water flows through the water cycle. / text

This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

More than half a century ago, Piaget concluded from an investigation of children’s representational thinking about the nature of space that the development of children’s representational thought is topological before it is Euclidean. This conclusion, commonly referred to as the “topological primacy thesis,” has essentially been rejected. By giving emphasis to the ideas that develop rather than the order in which they develop, this work set out to develop a new form of non-metric geometry from young children’s early and intuitive topological, or at least non-metric, ideas. I conducted an eighteen-week teaching experiment with two children, ages six and seven. I developed a new dynamic geometry environment called Configure that I used in tandem with clinical interviews in each of the episodes of the experiment to elicit these children’s non-metric conceptions and subsequently support their development. I found that these children developed significant and authentic forms of geometric reasoning. It is these findings, which I refer to as qualitative geometry, that have implications for the teaching of geometry and for research into students’ mathematical reasoning. / text