The short-term responses of Cassiope tetragona, a high arctic evergreen shrub, to variations in growing season climate were examined using experimental manipulations of temperature and growing season length at Alexandra Fiord, Ellesmere Island. Surface temperatures in the field were increased an average of 1-2 °C in two communities using open-top greenhouses. Growing season length was altered in a snowbed community by using manual snow manipulations to change the date of snowmelt. Growth and reproductive responses of Cassiope tetragona to these manipulations were observed over two field seasons following treatment establishment. Natural variations in vegetative and reproductive characteristics of Cassiope tetragona were also monitored in unmanipulated communities selected to represent a range of environmental conditions at the study site. Retrospective analysis of past Cassiope growth and reproduction was used to provide a record of variations in productivity spanning 25-35 years which could be related to climate records from Ellesmere Island. For the retrospective analysis, patterns of internode lengths were used to delimit sections of annual growth and chronologies of annual stem elongation, leaf number and flower number were then analyzed using methods similar to those applied to tree-ring studies. In general, the reproductive parameters of Cassiope tetragona were observed to be highly responsive to short-term variations in growing season climate, while vegetative production exhibited a much more conservative response. Flower production and rates of reproductive development were significantly stimulated by experimental warming. Retrospective analysis of flower production support field observations indicating that flower production is highly sensitive to annual variations in growing season temperatures. In contrast, shoot growth showed moderate responses to experimental warming. Records of past growth indicate that although vegetative production appears to be sensitive to annual variations in summer temperatures, the degree of responsiveness is much lower than for reproductive parameters. Net growth and reproduction were not stronly affected by natural or experimental variations in snowmelt timing, although phenology timing was significantly altered. The conservative growth response of Cassiope tetragona to short-term variations in climate is suggested to be related to constraints on plant phenology which may restrict flexibility in the period utilized by plants for aboveground growth. Preferential allocation of within-plant resources to reproductive structures during periods of ameliorated growing season climate may account for the observed strong reproductive responses to climate variations. Trade-offs betweeen growth and reproduction have important implications for predicting the long-term response of Cassiope tetragona to climate change. An understanding of within-plant allocation strategies is also important to the interpretation of past variations in growth and reproduction. Retrospective analysis of past Cassiope production is likely to be a very useful tool for investigating ecological relationships and past climate change. / Arts, Faculty of / Geography, Department of / Graduate

Le réseau de 5 télescopes Tcherenkov au sol H.E.S.S. (High Energy Stereoscopic System) permet de détecter des rayons gamma à très hautes énergies (E>50GeV) pour sonder les phénomènes non thermiques les plus violents de l'univers. Ces rayons gamma peuvent provenir de l'annihilation de particules de matière noire. L'astronomie gamma permet donc de rechercher les signatures de l'annihilation de particules de matière noire dans les régions denses de l'univers. Cette thèse est composée de trois parties. Après un bref rappel sur l'instrument H.E.S.S., sont présentés en premier lieu les tests de performance effectués pour l'étalonnage de la nouvelle électronique utilisée pour la modernisation des caméras des quatre télescopes CT1 à 4. L'analyse des premières données de la caméra CT1 modernisée montre la réduction du temps mort de lecture du réseau qui permettra de bénéficier pleinement de la stéréoscopie entre les 5 télescopes du réseau. La deuxième partie de la thèse traite des 10 ans d'observations de la région du Centre Galactique avec H.E.S.S. ainsi que les récentes observations obtenues avec l'ajout en 2012 du télescope de 28 mètres de diamètre (CT5) au centre du réseau. L'analyse des données de CT5 en direction de la source centrale HESS J1745-290 permet d'avoir accès aux événements aux plus basses énergies accessibles avec H.E.S.S. (100 GeV). Le spectre de la source centrale est en très bon accord avec celui de HESS J1745-290 mesuré avec CT1-4 et les données en dessous de 150 GeV permettent de raccorder ce dernier à celui de la source Fermi 3FGHL J1745.6-2859c.Dans la troisième partie, les 10 ans de données dans la région du Centre Galactique avec la première phase de H.E.S.S sont analysés pour rechercher un signal d'annihilation de matière noire à l'aide d'une méthode de vraisemblance utilisant les caractéristiques spectrale et spatiale du signal de matière noire par rapport à celles du bruit de fond. En l'absence de signal matière noire, les contraintes sont calculées sur la section efficace d'annihilation et, pour la première fois, un réseau de télescope Tcherenkov au sol est capable de sonder la section efficace d'annihilation thermique dans le cas d'un profil de matière noire piqué. La sensibilité sur la section efficace d'annihilation de l'instrument H.E.S.S. utilisant CT5 est ensuite présentée vers le Centre Galactique et la galaxie naine récemment découverte Reticulum II. La dernière partie de cette thèse étudie le potentiel du futur réseau de télescopes Tcherenkov CTA, (Cherenkov Telescope Array) pour la détection d'un signal d'annihilation de matière noire. Vers la région du Centre Galactique le signal de matière noire attendu est significativement augmenté par la contribution de rayons gamma produits par effet Compton inverse d'électrons et positrons énergétiques sur les champs de radiation ambiants. La sensibilité obtenue permet à CTA de sonder la section efficace d'annihilation thermique dans tous les canaux d'annihilation dans le cas d’un profil de matière noire piqué. L’impact sur la sensibilité de CTA des erreurs systématiques et de l’émission diffuse mesurée par Fermi est aussi montré. Dans le cas des galaxies naines satellites de la Voie Lactée, les performances de CTA permettent de les considérer comme des objets spatialement étendus, et d'obtenir une sensibilité compétitive avec celle du Centre Galactique dans le cas d’un profil à cœur de plusieurs kpc. Dans le cas d'un signal de matière noire de type ligne, CTA sera capable de contraindre fortement des modèles spécifiques de matière noire au TeV grâce à l'effet Sommerfeld, comme le Wino et le MDM-5plet. / The ground-based Cherenkov telescope array H.E.S.S. (High Energy Stereoscopic System) is able to detect gamma rays at very high energies (E> 50GeV) to probe the most violent non-thermal phenomena in the universe. These gamma rays can also come from dark matter particle annihilation. Gamma-ray astronomy provides a promising avenue to search for signatures of these annihilations in overdense regions of the universe. This thesis is composed of three parts. After a brief reminder of the H.E.S.S. instrument, the performance tests to calibrate the new electronics used for the modernization of the four cameras CT1-4 telescopes are presented. The analysis of the upgraded camera raw data shows a reduction global array dead time allowing to maximize the benefit of the stereoscopy between the 5 telescopes. The second part of the thesis deals with 10 years of observations of the Galactic Center region with H.E.S.S. and recent observations taken with the 28-meter-diameter telescope (CT5) located at the center of the array. The data analysis towards the central source HESS J1745-290 provides access to events at lower energies (100 GeV). The spectrum of the central source is in very good agreement with the one of HESS J1745-290 measured with CT1-4 and data below 150 GeV enable to connect it to the Fermi 3FGHL J1745.6-2859c source spectrum. In the third part, the 10 years of data in the region of the Galactic Centre with the first phase of H.E.S.S. are scanned for a dark matter annihilation signal using a likelihood method using the spectral and spatial characteristics of the dark matter signal compared to background. No dark matter signal is detected. The constraints are calculated on the annihilation cross section and, for the first time, a ground-based Cherenkov telescope array is capable to probe the thermal cross section in the case of a cuspy dark matter profile. The sensitivity of the annihilation cross section of the H.E.S.S. instrument using CT5 is then presented toward the Galactic Center and the recently discovered dwarf galaxy Reticulum II. The last part of the thesis studies the potential of the future ground-based instrument CTA (Cherenkov Telescope Array) for the detection of dark matter annihilation signal. Towards the Galactic Center region, the expected dark matter signal is significantly increased by the contribution of gamma rays produced by inverse Compton process of energetic electrons and positrons on ambient radiation fields. The sensitivity obtained enables CTA to probe the thermal cross section in all annihilation channels for a cuspy dark matter profile. The impact on CTA sensitivity of systematic errors and diffuse emission measured by Fermi is also shown. In the case of dwarf galaxy satellites of the Milky Way, the CTA performances enable to consider them as extended objects and provide a competitive sensitivity with the Galactic Centre sensitivity for a kpc-core profile. In the case of a line signal, CTA will be able to strongly constrain specific TeV dark matter models through the Sommerfeld effect, as Wino and MDM-5plet.

This mater's thesis deals with introducing principles of debugging and debuggers. The thesis examines in detail format of debugging information and it describes the design of debugger created within the project Lissom. Furthermore, the thesis also contains implementation of each designed part, which the debugger consists of. Last part of this thesis deals with testing of the implemented solution with two types of processor architectures and it also contains the conclusion of the results.

Application specific instruction set processors become part of every day life although it's not always visible at first sight. During their development it's needed to somehow describe their architecture, instruction set and behavior. To make their developement worth, it's necessary to be able to create applications for these processors and during application development errors are always made. Debuggers serve to discover and help fixing them. This paper summarises some basic information to debugger development and describes implementation for processors created using the Lissom project.

博士（社会学） / 108p / 一橋大学

No description available.

Dwarf galaxies tend to have redder [3.6 μm] - [4.5 μm] Spitzer broadband colors than spirals. To investigate this effect, for a large sample of dwarf galaxies we combine Spitzer fluxes with data at other wavelengths and compare to population synthesis models. Lower metallicity systems are found to have redder [3.6] - [4.5] colors on average, but with considerable scatter. The observed range in [3.6] - [4.5] color is too large to be accounted for solely by variations in stellar colors due to age or metallicity differences; interstellar effects must contribute as well. For the reddest systems, the 4.5 μm luminosity may not be a good tracer of stellar mass. We identify three factors that redden this color in dwarfs. First, in some systems, strong Brα emission contributes significantly to the 4.5 μm emission. Second, in some cases high optical depths lead to strong reddening of the starlight in the Spitzer bands. Third, in some galaxies, the nebular continuum dominates the 4.5 μm flux, and in extreme cases, the 3.6 μm flux as well. The harder UV radiation fields in lower metallicity systems produce both more gaseous continuum in the infrared and more Brα per star formation rate. The combination of these three factors can account for the 4.5 μm excess in our sample galaxies, thus it is not necessary to invoke a major contribution from hot dust to the 4.5 μm band. However, given the uncertainties, we are not able to completely rule out hot dust emission at 4.5 μm. More spectroscopic observations in the 3-5 μm range are needed to disentangle these effects.

No description available.

Les exoplanètes peuvent être détectées par plusieurs méthodes. De celles-ci, la méthode des Vitesses Radiales (RV) est dite indirecte, car l'on observe le spectre lumineux de l'étoile hôte et non la planète directement. Or, plusieurs facteurs influencent les variations lumineuses d'une étoile hormis la présence d'un compagnon. La photosphère des étoiles comprend des régions plus sombres appelées taches stellaires causées par de forts champs magnétiques qui restreignent le déplacement de l'énergie vers la surface. Lorsque l'étoile tourne, elles se déplacent produisant ainsi des variations dans le spectre de l'étoile similaires à celles induites par les corps l'orbitant. C'est pourquoi la modélisation de l'activité stellaire est essentielle pour la recherche d'exoplanètes. Il existe maints indicateurs d'activité dont la photométrie et les bissectrices et le Full Width at Half Maximum (FWHM) obtenus du profil moyen des raies spectrales. Ils peuvent être modélisés à l'aide d'outils mathématiques comme les Processus Gaussiens (GP). L'étoile GL229 A est une naine rouge située à 5.75 parsecs autour de laquelle orbite la première naine brune, GL229 B, découverte par imagerie directe en 1995. À mi-chemin entre planètes géantes et étoiles naines, ces objets sous-stellaires n'ont pas acquis la masse nécessaire pour déclencher la fusion nucléaire de l'hydrogène lors de leur formation. Le système GL229 fut aussi observé par différents télescopes dotés d'instruments permettant d'obtenir des mesures de RV. Ceci mena, en 2014 et 2020, à la détection de deux exoplanètes, GL229 A b et A c aux masses minimales de 32 et 7 masses terrestres. Ce mémoire présente une réanalyse des RV obtenues avec HARPS, un spectrographe échelle. En modélisant le FWHM avec un GP, il peut être démontré que les signaux précédemment identifiés comme d'origine planétaire correspondent en fait à des signaux d'activité stellaire. / Several methods can detect exoplanets. Of these, the Radial Velocity (RV) method is said to be indirect because the light spectrum of the host star is observed and not the planet directly. However, several factors influence a star's luminous variations apart from a companion's presence. The photosphere of stars contains darker regions called star spots caused by strong magnetic fields that restrict the movement of energy to the surface. When the star rotates, these spots move, producing variations in the star's spectrum similar to those induced by the bodies orbiting it. Hence, stellar modelling activity is essential when searching for exoplanets. Many activity indicators, including photometry and bisectors and Full Width at Half Maximum (FWHM) obtained from the average spectral line profiles, can be modelled using tools such as Gaussian Processes (GP). GL229 A is a red dwarf located at 5.75 parsecs around which orbits a brown dwarf, GL229 B, firstly discovered through direct imaging in 1995. Halfway between giant planets and dwarf stars, these substellar objects did not acquire the mass necessary to trigger nuclear hydrogen fusion during their formation. The GL229 system was also observed by various telescopes equipped with instruments making it possible to obtain RV measurements. This led, in 2014 and 2020, to the detection of two exoplanets, GL229 A b and A c, with minimum masses of 32 and 7 Earth masses. This thesis presents a re-analysis of the RVs obtained from HARPS spectra, an échelle spectrograph, for the Gliese 229 system. By modelling the FWHM with a GP, we show that previously identified planetary signals are not real and result from stellar activity.

The purpose of this study is to highlight how Pär Lagerkvist’s fictional dwarf, a symbol of the deformed in man but is not always visible on the outside, despises weakness and peace and how the desire for power is expressed in the novel. These aspects in turn lead to contempt for love and mercy, the absence of which implies hostility, something that has moral consequences. The overall moral theme is highlighted from an anti-Nazi perspective through the three images of women with the help of the narratological concept of unreliable narrator. The material used as a basis for the study is the first edition of Lagerkvist’s novel The Dwarf from 1944. Primarily, narratological theory has been used with regard to the concept of unreliable narrator, something that belongs to modern narratology and fiction theory. Unreliable storytelling means that there is a difference between this discourse and the sanctioned content. The unreliable narrator has emerged as a concept in relation to the implicit author. To highlight the anti-Nazi perspective, I have used the moral philosopher Harald Ofstads Vårt förakt för svaghet. The power-theme which is central to the novel, is highlighted on the basis of Nietzsche, who according to Urpu-Liisa Karahka is important in the reading of Lagerkvist in general. Close reading, thematic analysis and narratological method are the methods applied in this study. Christer Johansson has presented and summarized an interesting starting point based on Wayne C. Booth, for narratological analysis where he works with four possible variants for unreliable storytelling. In terms of main results, the question of the dwarf as an unreliable narrator and example of Nazism in relation to the three female charachters show eight cases of false facts, four cases of misinterpretations of correct facts, eight cases regarding how a fictional narrator can make unreliable value judgements about certain fictional facts or circumstances, and finally four cases of how a fictional narrator can express unreliable perceptions of a more general kind, not directly related to individuals in the fictional world.