Heidelberg, Univ., Diss., 2002. / Computerdatei im Fernzugriff.

Heidelberg, Univ., Diss., 2002. / Computerdatei im Fernzugriff.

Heidelberg, University, Diss., 2001.

University, Diss., 2003--Heidelberg.

A growing body of evidence has established that smoking and gambling frequently co-occur. Despite high rates of co-occurrence, few studies have attempted to examine the extent to which nicotine can directly affect gambling behaviour. This dissertation further explores the relationship between smoking and gambling through a secondary data analysis and two laboratory-based experiments. First, a secondary data analysis was conducted using epidemiological data collected from a gambling prevalence survey in Newfoundland and Labrador. The results from this analysis revealed several associations between smoking and past 12 month gambling. Significant relationships were found between smoking and problem gambling severity scores, use of alcohol/drugs while gambling, money spent gambling, use of video lottery terminals (VLTs), and reasons for gambling related to positive reinforcement/reward and negative reinforcement/relief. Experiment 1 consists of a laboratory investigation of the acute effects of nicotine on subjective and behavioural responses to VLT gambling among gamblers who smoke. Twenty-eight (15 male) regular gamblers who smoke daily took part in two double-blind laboratory sessions where subjective and behavioural responses to gambling were assessed following administration of nicotine inhalers (NI; 4mg deliverable) or placebo inhalers (PI). It was found that NI significantly decreased tobacco-related cravings but did not affect gambling-related cravings, VLT betting, or subjective responses. In Experiment 2, the acute effects of nicotine on subjective, physiological, and behavioural gambling responses were examined in VLT players who smoke following exposure to gambling-related cues. Thirty (20 male) VLT gamblers (identified as ‘moderate risk’ or ‘problem gamblers’) who smoke daily were assigned to a nicotine lozenge (NL; 4mg deliverable) or placebo lozenge (PL) condition. Subjective and behavioural responses were assessed at baseline, following lozenge administration, following neutral cues, and following gambling cues. It was found that NL significantly reduced tobacco-related cravings but didn’t affect gambling-related cravings, the decision to play a VLT, or other subjective responses. The aggregate findings of Experiments 1 & 2 indicate that acutely administered nicotine reduced tobacco-related cravings without increasing the reinforcing value of gambling. These results suggest that use of nicotine replacement therapies (NRT) may be a safe option for gamblers who are attempting to quit smoking.

University, Diss., 2002--Heidelberg.

Aujourd’hui, plus de 1800 planètes qui orbitent autour d’étoiles en dehors du système solaire ont été découvertes. La plupart des planètes découvertes actuellement a été révélée grâce aux méthodes indirectes. Par contre, avec ce type de techniques, la caractérisation des planètes ne peut pas être complète si on n’utilise pas plusieurs techniques simultanément. Aussi, pour obtenir le spectre de la planète, il doit y avoir un transit et même dans ce cas là,le signal est très faible par rapport au signal de l’étoile. L’observation directe de ces objets, appellée imagerie directe, est maintenant possible grâce à des systèmes très avancés d’optique adaptative installés sur des télescopes de classe 8m. L’imagerie directe permet l’observation des planètes sufisamment lumineuses et éloignées de l’étoile principale en utilisant un masque qui cache la lumière de la dernière. Cette technique est donc efficace en particulier pour des systèmes jeunes et voisins car la luminosité intrinsèque de la planète diminue avec l’âge et la séparation réelle de la planète dépend de la distance du système. Dans le VLT au Paranal (Chili), deux instruments sont dédiés à ce type de recherche : NACO et SPHERE. SPHERE a vu sa première lumière en Mai 2014, et est maintenant prêt à commencer une enquête consacrée à la découverte de planètes autour de systèmes jeunes et voisins, NIRSUR. Cet instrument se compose de trois sous-systèmes : IRDIS, IFS et ZIMPOL. / In the year of the 20th anniversary of the discovery of the first extrasolar planet we can count more than 1800 companions found with different techniques. The majority of them are indirect methods that infer the presence of an orbiting body by observing the parent star (radial velocity, transits, astrometry). In this work we explore the technique that permits to directly observe planets and retrieve their spectra, under the conditions that they are bright and far enough from their host star. Direct imaging is a new technique became possible thanks to a new generation of extreme adaptive optics instruments mounted on 8m class telescopes. On the Very Large Telescope two instruments dedicated to the research for exoplanets with direct imaging are now operative: NACO and SPHERE. This thesis will describe the development and results of SPHERE from its predecessor NACO to its integration in laboratory and the final on sky results.

Since the identi cation of proto-planetary nebulae (PPNe) as transition objects between the asymptotic giant branch stars and planetary nebulae more than two decades ago, astronomers have attempted to characterise these exciting objects. Today many questions still elude a conclusive answer, partly due to the sheer diversity observed within this small subset of stellar objects, and partly due to the low numbers detected. Fortunately, many of these objects display a rich spectrum of emission/absorption lines that can be used as diagnostics for these nebulae. This dissertation presents a study of six PPNe using the relatively new (at NIR wavelengths) integral eld spectroscopy technique. This method has allowed the investigation of distinct regions of these nebulae, and in certain cases the application of magneto-hydrodynamic shock models to the data. The goal of this research has been to investigate the evolution of PPNe by detailed examination of a small sample of objects consisting of a full range of evolutionary types. Near-IR ro-vibrational lines were employed as the primary tool to tackle this problem. In all six sources the 1!0S(1) line is used to map the spatial extent of the H2. In three of these objects the maps represent the rst images of their H2 emission nebulae. In the case of the earliest-type object (IRAS 14331-6435) in this sample, the line map gives the rst image of its nebula at any wavelength. In the only M-type object (OH 231.8+4.2) in the sample, high-velocity H2 is detected in discrete clumps along the edges of the bipolar out ow, while a possible ring of slower moving H2 is found around the equatorial region. This is the rst detection of H2 in such a late-type object but due its peculiarities, it is possibly not representative of what is expected of M-type objects. In IRAS 19500-1709, an intermediate-type object, the line map shows the H2 emission to originate in clumpy structures along the edges of a bipolar shell/out ow. The remaining three objects have all been the subject of previous studies but in each case new H2 lines are detected in this work along with other emission lines (Mg ii, Na i & CO). In the case of IRAS 16594-4656, MHD shock models have been used to determine the gas density and shock velocity. Two new python modules/classes have been written. The rst one to deal with the data cubes, extract ux measurements, rebin regions of interest, and produce line maps. The second class allows the easy calculation of many important parameters, for example, excitation temperatures, column density ratio values, extinction estimates from several line-pairs, column density values, and total mass of the H2. The class also allows the production of input les for the shock tting procedure, and simulated shocks for testing this tting process. A new framework to t NIR shock models to data has been developed, employing Monte Carlo techniques and the extensive computing cluster at the University of Hertfordshire (UH). This method builds on the approach used by many other authors, with the added advantages that this framework provides a method of correctly sampling the shock model parameter space, and providing error estimates on the model t. Using this approach, data from IRAS 16594-4656 have been successfully modelled using the shock models. A full description of this class of stellar objects from such a small sample is not possible due to their diverse nature. Although H2 was detected across the full spectral vi range of post-AGB objects, the phase at which H2 emission begins is still not clear. The only M-type object in this work is a peculiar object and may not be representative of a typical post-AGB star. The H2 PPNe appear to be located at lower Galactic latitudes (b 20 ) than the total PPNe population, possibly pointing to an above average mass and hence younger age of these objects.

L'Optique Active est une discipline en plein essor qui a obtenu ses lettres de noblesse sur les plus grands télescopes du monde. Les grands projets instrumentaux en cours ou à venir intègrent désormais l'Optique Active à tous les niveaux de leur conception. Les miroirs actifs présentent l'avantage d'une grande qualité de surface combinée à une versatilité et une flexibilité qui en font des pièces indispensables pour réaliser des télescopes et instruments de plus en plus performants an d'atteindre les objectifs scientifiques du futur. Trois techniques d'Optique Active, basées sur le polissage sous contrainte et la déformation in situ, sont au cœur du travail présenté. Ces techniques sont développées dans le cadre de trois projets majeurs de la communauté astronomique : 1) le miroir secondaire déformable du VLT, 2) l'instrument de recherche d'exoplanètes Sphere sur le Vlt et 3) le projet de spectrographe grand champ multi-objet Eagle pour l'European-Elt. A partir de la théorie des plaques minces en flexion, les modèles analytiques permettent de définir les configurations de charges et distributions d'épaisseur des substrats de miroirs à déformer. Les analyses par éléments finis sont un atout majeur pour l'optimisation et la validation des techniques proposées. De nombreuses passerelles sont utilisées ou créées entre élasticité, théorie des aberrations et analyse spectrale an d'évaluer la qualité optique des déformations de surfaces des miroirs. Trois procédés de fabrication sont ainsi développés de bout en bout an de produire une lame mince convexe hyperbolique, des miroirs toriques de grande précision et de miroirs à toricité variable de grande dynamique, le point commun de ces procédés étant l'excellente qualité de surface des miroirs.

<p>Syftet med denna undersökning var att låta källor som citerats i lokaltidningen Vestmanlands Läns Tidning (på Västerås-sidorna under vecka 16, 2007) berätta vad de tyckte om intervjun och artikeln och jämföra resultatet med tidigare studier av källors erfarenheter, en av storstadspress och en av kvällspress. En jämförelse mellan personer som är vana och de som inte är vana vid att vara med i pressen och mellan elit - och icke-källor gjordes också. Resultatet visade att de flesta (i samtliga tidningar) var nöjda med sin medverkan, men det finns undantag, till exempel blev sex personer helt eller delvis felciterade. Många vana källor (i VLT) uttrycker att de vet hur pressen fungerar, (gällande vinkling och förenkling av material) och att deras förväntningar var realistiska, även om en del är oroliga för att det ska bli fel. En källa sammanfattade denna ängslan i meningen ”man är alltid rädd att de ska skriva något man inte har sagt.” En slutsats är att de källor som är intervjuade i lokalpressen är vana vid det, oavsett om de är elit - eller icke-elitkällor. Nästan alla icke-elitkällor i VLT har själva initierat till artikeln, det vill säga agerat aktörer. En annan slutsats, orelaterad från undersökningens utgångssyfte, är alltså att källor på olika sätt påverkar vilka nyheter som blir valda.</p>