L’usage excessif des pesticides a entraîné de nombreux effets néfastes sur l’environnement et aussi sur la santé des populations. Il est donc important d’approfondir, nos connaissances sur leur comportement dans toutes les sphères de l’environnement et de mettre en place de nouvelles technologies de dépollution d’effluents chargé en pesticides avant leur rejet dans le milieu naturel. Le travail de cette thèse est situé dans ce contexte. Le premier volet de thèse a été consacré au traitement des solutions aqueuses chargées par deux fongicides (imazalil, thiabendazole), par le procédés d’oxydation électrochimiques directe, afin d’optimiser les différents paramètres expérimentaux de leur dégradation. Ces études confirment l’efficacité du procédé électrochimique dans le traitement des eaux polluées par les pesticides, avec un taux de minéralisation qui dépasse 80%. D’autre part, les résultats obtenus dans ce travail ont montré que la nature du matériel d’anode a une grande influence sur la performance du procédé d’oxydation. Dans la deuxième partie, nous avons étudié la réactivité atmosphérique en phase gazeuse des composés aromatiques hétérocycliques azotés. Ces espèces sont attendues lors de la dégradation des pesticides. Les études cinétiques de ces composés avec l’ozone et les radicaux OH, ont été effectuées dans une chambre de simulation atmosphérique à différentes températures. Les réactions d’ozonolyse de ces composés sont très lentes. Dans le cas de leur réaction avec les radicaux OH, les résultats obtenus montrent que la réactivité atmosphérique de ces composés dépend fortement de leur structure moléculaire. En effet, les composés hétérocycliques aromatiques à 5 atomes présentent une réactivité plus importante vis-à-vis les radicaux OH, par rapport aux composés hétérocycliques aromatiques à six atomes. Par ailleurs, ces études ont montrés que la présence des atomes d’azote dans le cycle aromatique a un effet désactivant sur la réactivité de ces composés avec les radicaux OH. Sur le plan spectroscopique, les spectres d’absorption UV-visibles des composés : 1,2,3 triazole, pyrazole, pyrazine, pyrimidine,et pyridazine, ont été déterminés en phase gazeuse et leurs constantes de photodissociation atmosphérique ont été estimées. Enfin, les données cinétiques et spectroscopiques obtenues ont permis de discuter les implications atmosphériques de ces composés en termes de durée de vie par rapport aux différents processus de dégradation atmosphérique / This work concerns a new insight of treatment of organic pollutants pesticides before their rejection in the natural environment. This phenomenon is increasing dramatically causing many adverse effects on the environment and the health. The first step of this work focused on the treatment of aqueous solution charged with fungicides by direct electrochemical processes. The efficiency of this latter in the treatment of waters polluted by pesticides has been confirmed with a mineralization rate exceeding 80%. In the other hand, the obtained results have ensured that the nature of the anode material is one of the keys and factors having an influence on the oxidation pathway. The second step conducted by absorption spectroscopy and focused on the atmospheric reactivity in the gas phase of nitrogenous heterocyclic aromatic compounds. These species are expected during the degradation of pesticides. The use of an atmospheric simulation chamber at different temperatures allowed us to follow the kinetics of these compounds with ozone and OH radicals. The kinetics of ozonolysis of these compounds is very slow. The molecular structure is the factor, according to the results obtained, controlling the atmospheric reactivity of these compounds in the case of their reaction with OH radicals. Indeed, the 5-atom aromatic heterocyclic compounds have a greater reactivity with respect to the OH radicals, compared with six-membered aromatic heterocyclic compounds. Moreover, according to these studies, the presence of nitrogen atoms in the aromatic ring has a deactivating effect on the reactivity of these compounds with the OH radicals. Spectroscopically, the UV-visible absorption spectra of the compounds 1,2,3-triazole, pyrazole, pyrazine, pyrimidine, and pyridazine were determined in the gas phase and their atmospheric photodissociation constants were estimated. Finally, the kinetic and spectroscopic data obtained made it possible to discuss the atmospheric implications of these compounds in terms of their lifetime with respect to the different processes of atmospheric degradation.

This diploma thesis is focused on design and prototyping of wireless optical link for an indoor usage. In the beginning of the thesis frequency spectrums of infrared, visible and ultraviolet light are described by its typical qualities such as values of attenuation or reflection capability. On the basis of this analysis, a proper wavelength has been chosen for usage at the engineered communication system. Next part is devoted to selection of suitable communication components on basis of its declared qualities. In the following chapter this qualities are in carefully measured and after that they are compared with values provided by its manufacturer. The following section is devoted to design schemes of transceiver modules. After completion of the design the manufacturing of PCB, mounting components and the analysis of their distribution was described. The last part of this thesis deals with testing of created prototype in terms of maximum transmission distances and operating frequencies. At the very end of this project, in one small section ways to improve system characteristics was discussed.

One of the best ways how hosts may defend their clutch against brood parasitism is recognition and rejection of parasitic eggs. It has been documented that ability to percept UV light in birds affects their behaviour. By using a spectrophotometer we found that Reed Warbler (Acrocephalus scirpaceus) eggs and Common cuckoo (Cuculus canorus) eggs differ mainly in brightness but also in UV hue. We investigated the influence of birds' UV vision on recognition and rejection of parasitic eggs. Therefore we performed three experiments to reveal the role of eggshell UV reflectance on egg rejection in this host. In the first experiment, we parasitized clutches with artificial white eggs differing only in UV reflectance (UV- and UV+). In the other two, we experimentally reduced UV reflectance from conspecific and host own eggs. We used a UV light blocker, which did not influence the reflectance shape in the other parts of spectra. As a control we used a group of conspecific and own eggs coated in Vaseline, which did not affect eggshell reflectance. In each experiment, we monitored host response to parasitic eggs. Because the Reed Warbler's eggs reflect UV radiation themselves, we expected that white UV- eggs would be rejected as well as the eggs coated in UV blocker at a higher rate than white UV+ eggs and...