The subject of this thesis is the analysis and modeling of the active galactic nucleus PKS 1510-089. The aim is to present a thorough background of active galactic nuclei combined with the analysis and modeling of a specific active galactic nucleus. The results will then be  linked to previous research and theories about active galactic nuclei. The data used in the analysis were retrieved from the Fermi Gamma-ray Space Telescope. A light curve analysis that extended over 12 years provided knowledge about variability and presented four interesting flaring periods. The four periods underwent a spectral analysis, and the results showed that a log parabolic curvature could best describe all four periods. The last step before the modeling was to create spectral energy distributions for all four periods to retrieve spectral points from wavelengths other than those available from Fermi. Unfortunately, there were only sufficient data for one period. That period was later used in the modeling and resulted in a well-fitted external Compton model, which was compared, with relatively good results, with previous research.

As of June 2020, the first all-sky X-ray survey with the eROSITA instrument aboard the spacecraft Spektr-RG has been completed. A high percentage of the 1.1 million objects included in the survey are expected to be active galactic nuclei (AGN). Such an extensive catalogue of X-ray sources offers a unique opportunity for large scale observations of distinct classes of X-ray emitters. This report explores methods of refining the catalogue to include only candidates for lensed AGN. Of the differing types of AGN known, quasi-stellar objects, or QSOs, are some of the most luminous, meaning they are well-suited for observation over large distances. This is particularly befitting for observation of gravitationally lensed objects as, for lensing effects to take place, large distances are required over which more faint objects would not be able to be viewed. An indication of strong gravitational lensing is several images of the same object seen in close proximity on the sky. In order to reduce the data to more likely candidates, counterparts within a given radius are found in the second data release from Gaia; a survey in the optical with higher resolution than eROSITA. An algorithm is produced which removes most likely stellar Gaia sources using their X-ray to optical flux ratios and astrometry parameters. The Gaia sources which have no neighbours within another given radius are then also removed, leaving a catalogue of potential multiply lensed QSOs. This automated script was then applied to an eROSITA catalogue and the results compared with known lenses. The remaining sources were also checked visually using Pan-STARRS optical survey data. The results seem to be promising, although a great deal further refinement is needed through visual inspection to find the most promising candidates for lensed QSOs. / <p>Written under the joint supervision of Georg Lamer at the Leibniz Institute for Astrophysics in Potsdam. The presentation was held online at the Institute due to the COVID-19 pandemic.</p>

Blazars are a type of Active Galaxy that emit strong astrophysical jets. The association of a HE gamma-ray flare from the blazar TXS 0506+056 to the IceCube-170922A neutrino event in 2017, opened the possibility to a link between these two events. In this thesis, we will look at the HE gamma-ray behavior of TXS 0506+056 using data obtained from the Fermi-LAT by taking into account the other set of neutrino events associated with this source from 2014-2015. We will investigate whether both neutrino events present with comparable HE gamma-ray behavior by analyzing the lightcurves and the spectra for a quiet state, the 2014-2015 period, and the flare centered around the neutrino event from 2017. The results of the analysis performed in this thesis show no strong indication of a change in the gamma-ray behaviour in these potential neutrino detections.

L'objectif général de cette thèse est d'explorer l'impact des lésions du cervelet sur les séquelles motrices et cognitives des enfants traités pour tumeur du cervelet maligne ou bénigne. En nous basant sur trois études cliniques, nos objectifs généraux ont été (1) d'examiner si ces enfant présentaient des déficits dans l'établissement d'automatismes moteurs et cognitifs, (2) de préciser les facteurs associés aux difficultés d'automatisation et (3) d'examiner l'impact de ces difficultés sur la scolarité et le devenir à long terme de ces enfants. La première étude avait pour objectif spécifique d'examiner le devenir à long terme de 46 adultes et de 18 adolescents traités dans l'enfance chirurgicalement pour un astrocytome pilocytique du cervelet. Elle a mis en évidence un devenir à long terme satisfaisant dans l'ensemble, bien que des difficultés cognitives et motrices aient été rapportées, en particulier par les sujets qui ont le plus réussi leurs parcours scolaires. La perte d'autonomie était associée à des complications postopératoires telles que le mutisme cérébelleux et l'invasion du tronc cérébral. La deuxième étude a porté sur une cohorte de 17 enfants et adolescents traités pour un astrocytome pilocytique cérébelleux. Elle a exploré l'automatisation de la lecture et discuté la théorie cérébelleuse de la dyslexie. Les résultats ont mis en évidence une difficulté de suppression des mouvements articulatoires chez la plupart des sujets qui était associée à un faible indice de Mémoire de Travail Verbale. La troisième étude a porté sur 16 enfants traités pour un astrocytome pilocytique du cervelet et 16 enfants traités pour un médulloblastome. Elle avait pour objectifs (1) d'étudier l'apprentissage moteur et différents automatismes cognitifs intervenant notamment dans la lecture et le calcul mental et (2) de préciser les relations entre les différentes mesures de la difficulté d'automatisation motrice et cognitive. Les résultats ont confirmé la difficulté de suppression des mouvements articulatoires et ont montré que les enfants traités pour tumeur du cervelet se différenciaient des enfants sains de âge par un apprentissage moteur moindre, en particulier avec la main non dominante et par une lenteur en lecture, en calcul mental, en dénomination rapide et en double tâche. Par ailleurs, l'atteinte des noyaux dentelés était liée à une baisse de l'efficience intellectuelle, en particulier chez les enfants traités pour un médulloblastome, à un apprentissage moteur moindre avec la main dominante, à une difficulté de suppression des mouvements articulatoires, et à une lenteur de calcul mental. Ce travail de thèse offre des résultats pionniers dans la compréhension de l'impact des lésions cérébelleuses sur les apprentissages chez l'enfant. / The general aim this doctoral dissertation is to explore the impact of cerebellar lesions on motor and cognitive sequelae in children treated for malignant or benign tumor of the cerebellum. In three clinical studies, we in (1) examine whether these children exhibited deficits in motor and cognitive automation, (2) identify factors associated with difficulties in automation and (3) examine the impact of these difficulties on schooling and long-term outcome. The first study examines the long-term outcome of 46 adults and 18 adolescents treated surgically in childhood for cerebellar pilocytic astrocytoma. Most subjects showed a positive long-term outcome, despite report of cognitive and motor difficulties, especially by subjects with successful school careers. The loss of autonomy was associated with postoperative complications, post cerebellar mutism, or invasion of the brain stem. The second study in 17 children and adolescents treated for pilocytic cerebellar astrocytoma aimed to examine the automation of reading and to discuss the cerebellar theory of dyslexia. The results highlighted a difficulty of suppressing articulatory movements in most subjects, associated with low index of Verbal Working Memory. The third study concerned 16 children treated for pilocytic astrocytoma of the cerebellum and 16 children treated for medulloblastoma. Its objectives were to (1) investigate motor learning and different cognitive automations involved in particularly in reading and mental calculation (2) clarify the relationship between different measures of motor and cognitive automation. The results confirmed the difficulty to suppress articulatory movements and showed lower motor learning effect, especially with the non-dominant hand, slowness in reading, mental calculation, rapid naming and dual task. Furthermore, dentate nuclei damage was linked to lower intellectual efficiency (IQ), particularly in children treated for medulloblastoma; to a lesser motor learning for the dominant hand, a difficulty to suppress articulatory movements, and slowness in mental calculation. This work offers pioneer results in understanding the impact of cerebellar lesions in children learning.

The origin of Ultra-High-Energy Cosmic Rays (UHECRs) is still an open question in Astrophysics. The scope of this thesis is the study of the termination shocks in the jets of radiogalaxies 3C 105, 3C 227, and 3C 445 as cosmic rays accelerators. We assume the diffusive shock acceleration (DSA) and that the maximum energy is determined by the escape of cosmic rays downstream of the shock due to the magnetization. We find maximum achievable energy of non-thermal electrons and protons, which appeared to be only~TeV. Therefore the reverse shocks of AGNs' jets are not the sources of UHECRs. We also implement the model, where the scattering centers for the DSA emerge from the non- resonant hybrid instabilities in plasma. We take into account the results from the numerical simulations and observations that indicate the amplification of the magnetic field by orders of magnitude, and we obtain results that qualitatively fit the simulation outcome.

京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第20897号 / 理博第4349号 / 新制||理||1624(附属図書館) / 京都大学大学院理学研究科物理学・宇宙物理学専攻 / (主査)准教授 川畑 貴裕, 教授 永江 知文, 教授 鶴 剛 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

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Numerous studies have focused on identifying novel probiotic-based treatment options for immune homeostasis maintenance and favorable modulation of the gut microbiota which acts as a key regulator of the gut-brain axis. Recently, probiotics interventions are gaining interest as effective approaches to treat neuropsychiatric disorders through the gut-brain axis. However, there is limiting knowledge about probiotics' effects during puberty on the developing brain and immune responses. Probiotic intake could offer a strategy to counteract the immune, microbial and behavioral disturbances induced by inflammatory LPS. Thus, we hypothesized that the intake of a novel probiotic bacterium Rouxiella badensis subsp. acadiensis would modulate the immune response and that pubertal administration could mitigate LPS- induced inflammation and prevent enduring behavioral changes later in life. We investigated the interaction of the probiotic with the intestinal mucosa and its ability of modulating the gut mucosal immunity (Article 1). Next, we examined the ability of pubertal treatment with R. badensis subsp. acadiensis to alleviate LPS-induced anxiety-like and depression-like behaviors in adult male and female mice and to affect the expression of 5HT1A receptors in specific brain areas of adult mice (Article 2). We finally studied the ability of R. badensis subsp. acadiensis treatment during puberty to mitigate the effects of LPS on the immune system and on the gut microbiome composition (Article 3). These studies have demonstrated the ability of R. badensis subsp. acadiensis to survive the gastrointestinal conditions, interact with the gut epithelium and modulate the intestinal homeostasis. Pubertal use of the bacterium was associated with sex-specific effects on the acute immune response, microbiome structure, enduring neurobehavioral outcomes and the expression of 5HT1A receptors in specific brain areas, later in life. This dissertation emphasizes on the importance of puberty as a window of opportunities during which probiotic use can alleviate the long-term neural, behavioral, immunological and microbiome alterations induced by stress.