35 research outputs found
Tierfabelbilder In Der Malerei des 17.,18. Und 19. Jahrhunderts
Medieval and Early Modern Studie
Servant Leadership: How Daily and General Behaviors Interact
The present study takes a closer look at servant leadership from a daily diary perspective. We hypothesized daily servant leadership to positively relate to the follower resources: self-efficacy and optimism. We further proposed that this relation should be attenuated if followers do not perceive their leaders to also lead servantly on a general basis. In a diary study, 98 followers completed questionnaires over one week. Hierarchical linear modeling showed daily servant leadership to be associated with followers' daily self-efficacy, but not with followers' daily optimism. Additionally, for the proposed interaction of daily servant leadership with general perceptions of servant leadership, results confirmed the proposed interaction for followers' daily optimism, but not for daily self-efficacy
Génération de photons uniques indiscernables par une boîte quantique semi-conductrice dans une microcavité optique
L'un des principaux accomplissements scientifiques du siècle dernier est sans doute le développement de la Physique Quantique. Parallèlement, notre société est entrée dans l'ère de l'information. Aujourd'hui, théorie de l'information et théorie quantique se recoupent sous un champ d'activité émergent : le traitement de l'information quantique. Ce domaine propose de tirer parti des corrélations subtiles entre états quantiques pour effectuer des opérations de communication ou de logique. Ces travaux de thèse s'inscrivent dans ce contexte. Ils visent la génération d'états quantiques de la lumière, pour tester les prévisions contre-intuitives de la mécanique quantique, mais aussi pour l'ingénierie de dispositifs de traitement de l'information quantique. Ces états quantiques sont des photons uniques indiscernables, rayonnés par des boîtes quantiques uniques. S'il est bien connu aujourd'hui que ces nano-émetteurs émettent des photons uniques, des processus rapides de décohérence propres à la physique du solide détériore l'indiscernabilité entre photons successivement émis. Pour restaurer l'indiscernabilité entre photons, le processus d'émission est accéléré en couplant la boîte au mode d'une microcavité optique (un micropilier), de sorte que les photons sont émis avant qu'ils ne soient marqués par les processus déphasants. Ainsi, nous avons pu produire des photons uniques avec un degré d'indiscernabilité supérieur à 75%. Ces photons sont alors sujets à des phénomènes d'interférence peu communs : lorsque deux photons sont incidents sur les deux ports d'entrée d'une lame séparatrice, les deux photons ressortent de la lame toujours sur le même port de sortie.One of the main scientific achievement of the last century is certainly the development of quantum mechanics. Recently, computer scientists and engineers teamed with physical scientists to further our understanding of quantum phenomena, and to exploit this understanding to realize new devices with novel functionality for communication and computing, that can be directly engineered using correlations between quantum states, giving rise to a new field in physics : Quantum information science. These quantum states can be indistinguishable single photons. Our work aimed at the generation of such quantum states, from sefl-assembled quantum dots. These emitters can produce single photons on demand but the indistinguishability between photons is rapidly destroyed by decoeherence processes in the solid-state. In order to restore the indistinguishability between photons, the dot is coupled to the mode of a micropilar cavity, that accelerates its spontaneous emission rate by a factor 25, so that the photons are emitted before being marked by dephasing mechanisms. This acceleration leads to the generation of indistinguishable single photons with a degree of indistinguishability as high as 75%. In this context, two-photon interference phenomena occur, whereby two single photons entering the two input ports of a beamsplitter, emerge from the beamsplitter both in the same output port, as if they had "coalesced" into a two-photon state.ORSAY-PARIS 11-BU Sciences (914712101) / SudocSudocFranceF
Safety of a 1-Day Polyethylene Glycol 3350 Bowel Preparation for Colonoscopy in Children
OBJECTIVES: Electrolyte-free polyethylene glycol powder (PEG-3350) has been widely used for colonoscopy preparation (prep), however limited safety data on electrolyte changes exists with 1-day prep regimens. The primary aim of this study was to determine the proportion of patients with significant serum chemistry abnormalities pre- and at the time of colonoscopy. Secondary aims included evaluation of prep tolerance and bowel cleansing efficacy. METHODS: We performed a prospective descriptive observational study of pediatric patients scheduled for outpatient colonoscopy who received our standard 1-day, weight-based 4 g/kg PEG-3350 prep with a single stimulant laxative dose and had serum chemistry testing within 60 days prior to and at the time of colonoscopy. A standardized bowel cleanliness tool (Aronchick scale) was completed by the endoscopist. RESULTS: 155 patients had serum electrolytes data pre- and post-prep. Comparison of each patient\u27s chemistries demonstrated statistical equivalence with the 1 exception of blood urea nitrogen levels (p = 0.56). Hypokalemia was detected post-prep in 37 subjects (24%), but none had a serum level below 3.3 mmol/L, which was deemed to be of no clinical significance. Five patients were hypoglycemic post-prep; 3 wer