[en] This thesis starts with a review of the basic concepts of Astroparticle Physics including an introduction to neutrino astronomy. Then, a detailed discussion of AGN properties is given with emphasis on their possible neutrino emission. A systematic classification identifies generic AGN samples of promising candidate sources. It is shown that source stacking can improve the sensitivity to generic AGN classes with respect to standard methods. Thereafter a description of the AMANDA neutrino telescope and a review on itsproperties is given. Then, the generic AGN classes are analyzed using data collected by AMANDA. Two data sets are considered for the analysis. In a first step, the source stacking analysis is established on data collected by AMANDA-II in the year 2000. Then, the method is applied to the currently most sensitive data set, which has been collected in the years 2000-2003. The analysis of galactic candidate sources is discussed. In addition to the method of stacking of permanent sources, a time-dependent analysis of single sources is considered. An example for such an analysis is given by the analysis for periodic neutrino emission from the Crab Pulsar. Finally, the results of this thesis are summarized and a short outlook is given on possible extensions of the source stacking method and its application to the IceCube neutrino telescope currently under construction. (orig.)

No abstract available

No abstract available

[en] In this work, plasmodial antigens were examined for their ability to suppress the cellular immune response during lethal Plasmodium berghei infection. Splenic enlargement and the number and function of white spleen cells were assessed after injection of normal mice with irradiated parasitized erythrocytes (IPE) or with parasitized erythrocytes (PE) membranes. Both IPE and PE membranes caused splenomegaly and an increase in the number of splenic white cells with concurrent alteration of the relative proportions of T cells and macrophages. The percentage of T lymphocytes was fractionally diminished, but there was a marked increase in Lyt 2.2 positive (suppressor and cytotoxic) T subsets and in the number of splenic macrophage precursors. The pathological enlargement of the spleen was induced by various plasma membrane-derived antigens containing both proteins and carbohydrates. Splenocytes of mice injected with liposomes containing deoxycholate-treated PE or PE fractions showed both diminished interleukin 2 production and a decreased response to mitogen. It appears that some of the changes in the cellular immune response during P. berghei infection are a consequence of the massive provision of a wide spectrum of antigens, capable of suppressing the immune response. Thus, it may be appropriate to evaluate the possible negative effect of parasite epitopes that are candidates for vaccine

[en] Highlights: • Flow visualizations from experiments and simulations for two axisymmetric bodies. • Improved understanding of mean flow separation topology for hemisphere cylinder. • Modal analysis of unsteady fluid dynamics. • Discussion of possible hydrodynamic instabilities. -- Abstract: The understanding of unsteady three-dimensional separation is lagging behind the understanding of two-dimensional separation due to its greater complexity and the limited amount of data for universal or canonical flow problems. Three-dimensional separation occurs, for example, when low aspect ratio devices such as submarines and torpedoes are operated at large angles of attack, α. Two low aspect ratio geometries, the DARPA Suboff bare hull geometry, which is a prototypical submarine shape, and a hemisphere-cylinder geometry were investigated. Numerical simulations and water tunnel experiments for the Suboff geometry for a Reynolds number based on diameter of Re=10,000 show little flow separation at α=30°. A hemisphere-cylinder geometry was derived by replacing the Suboff forebody with a hemisphere. Simulations and water tunnel experiments were carried out for Re=2000 and 5000. For α=10° a large shedding separation bubble is observed on the leeward side. For α=30° two counter-rotating leeward vortices appear and shedding is reduced. Proper orthogonal decomposition and Fourier analysis in time are employed for investigating the unsteady fluid dynamics. Conclusions are drawn with respect to the mean flow topology and possibly relevant hydrodynamic instabilities

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No abstract available

[en] The current IceCube telescope consists of 9 operational detector strings and will be extended to more than 20 strings during this years polar summer season 2006/2007. The full integration of the AMANDA detector into IceCube operation will be finalized in this season. This includes hardware synchronisation, combined triggering, common event building and a combined data analysis strategy. In this contribution, the Joint Event Builder (JEB) collecting data from both detectors and providing a combined data stream to the online filtering are discussed. Furthermore, the expected performance of the detector based on Monte Carlo simulations of a combined AMANDA+23-string IceCube detector is presented. (orig.)

[en] The SFEN young generation (SFEN JG) was founded in the early 2000's to federate young professionals of nuclear industry and optimise skills and knowledge transfers between experienced professionals and the new generation. Since 2017 SFEN JG integrates students in nuclear engineering. Twice a year SFEN JG organizes events that gather around 100 young professionals and some guests from the industrial or political worlds. SFEN JG proposes also technical visits to show the diversity of the French nuclear industry. Every year SFEN JG organizes 'Atoms for the Future' an international forum that gathers young professionals around a topic to discuss. (A.C.)

[en] A coherent CO₂ lidar system has been modified to record various states of polarization of the backscattered radiation. Methods for measuring the degree of polarization in the backscattered radiation as well as the optical thickness of clouds are described and demonstrated successfully