7,056 research outputs found

    Graduate Catalog of Studies, 2023-2024

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    Clinical, immunological and genetic features of histiocytic disorders

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    Isotope reconstructions of East Asian Monsoon behaviour across Glacial Terminations I and II from Lake Suigetsu, Japan (IAP2−18−54)

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    Understanding the response of the East Asian Monsoon to rising temperatures is crucial in light of recent anthropogenic climate change and the vulnerability of East Asia to future climatic hazards. However, East Asian Monsoon dynamics during warming periods in the late Quaternary are poorly understood, particularly on decadal to millennial timescales. Significant sources of this uncertainty are the spatially and temporally heterogeneous responses of the East Asian Monsoon to submillennial temperature fluctuations. The conflicting patterns observed in available reconstructions of East Asian Monsoon strength suggest that the teleconnections acting during these intervals were complex. Understanding the behaviours of the East Asian Monsoon by accounting for links to remote climatic perturbations allows for a more holistic understanding of deglacial climate changes. A means of tackling this ambiguity is by contributing well−dated, high−resolution records of East Asian Monsoon evolution spanning Glacial Terminations I and II (which typify accessible, contrasting examples of rapid global warming) to the growing network of reconstructions from across the region. The aim of this thesis is to deconvolve East Asian Monsoon evolution during the last two glacial terminations by utilising the unique hydrological distribution of East Asian Monsoon precipitation over Japan to reconstruct both seasonal modes of the system (i.e., the East Asian Winter Monsoon and East Asian Summer Monsoon). This aim is met by the construction of isotope−based, season−specific East Asian Monsoon records across Glacial Terminations I and II using materials from the Lake Suigetsu sediment cores. This thesis is comprised of four interconnected research papers, preceded by an introduction and succeeded by a summary of findings, discussion of relevance, suggestions for future work and conclusions. In the first research paper, we utilise extended contemporary monitoring of the stable isotope composition of precipitation, river water and lake water in the Lake Suigetsu catchment to understand the factors affecting these variables and aid robust interpretation of isotope−based proxy reconstructions from the Lake Suigetsu sediment cores. Our results show that the composition of precipitation was influenced by the dual East Asian Monsoon system, and that these signals were then transferred to the lake system where they were combined with secondary local influences on lake water composition. Based on our knowledge of late Quaternary catchment dynamics, these observations suggest that the palaeo−isotope composition of Lake Suigetsu was closely related to the East Asian Monsoon. In the second research paper, we examine the influence of remote climatic processes on the East Asian Winter Monsoon and East Asian Summer Monsoon in Japan during Glacial Termination I by reconstructing trends in the strength of each seasonal mode. This is achieved using oxygen isotope analysis of diatom silica and compound−specific hydrogen isotope analysis of n−alkanoic acids from the Lake Suigetsu sediment cores. Our results support distinctive seasonal behaviours of the East Asian Monsoon during Glacial Termination I, with evidence for East Asian Winter Monsoon weakening and East Asian Summer Monsoon strengthening. The East Asian Summer Monsoon also exhibited variations in strength which were synchronous with Antarctic temperature fluctuations after 16,000 years ago, which supports a temporally restricted climatic link between Japan and the Southern Hemisphere at this time. In the third research paper, we reconstruct the East Asian Summer Monsoon in Japan during Glacial Termination II, and contrast the findings to those from Glacial Termination I. The reconstruction presented in this chapter, which is based on compound−specific hydrogen isotope analysis of n−alkanoic acids, provides evidence for early East Asian Summer Monsoon strengthening followed by a gradual weakening phase with submillennial−scale variability. Comparison of this record to others derived from mainland China supports the assertion that East Asian Summer Monsoon behaviours during Glacial Termination II were spatially heterogenous. Additionally, the different evolutions of the East Asian Summer Monsoon during Glacial Terminations I and II indicate that the system operated distinctively under contrasting boundary conditions, although the new reconstructions from Japan were consistently more closely linked with Southern Hemisphere (Antarctic) temperatures than Northern Hemisphere (Greenlandic) temperatures during both intervals. The fourth research paper was motivated by a lack of an absolute chronology for the oldest (pre−50,000 years ago) parts of the Lake Suigetsu sediment cores (which includes Glacial Termination II). In this paper, we appraise the luminescence characteristics of the cores using rapid profiling techniques. These are employed across four key time periods in order to assess the application of these methods for the detection of local and environmental shifts, and to assess the suitability of the core materials for luminescence dating. We show that the luminescence characteristics of the cores were susceptible to a range of environmental perturbations, best illustrating local changes by using high−resolution contiguous sampling. The feasibility of future luminescence dating is supported by quantifiable luminescence signals, and first order approximate ages suggest that blue light optically stimulated luminescence dating of feldspar provides the most accurate and most practical assessment of burial age. This technique should be the subject of dating efforts in pursuit of refinements to the Suigetsu core chronology before 50,000 years ago. The findings of this thesis contribute to our collective knowledge of East Asian Monsoon behaviours during glacial terminations. Critically, they represent a geographical expansion of the regional high−resolution record network to include Japan. The value of this process is demonstrated by the decoupled evolutions of each seasonal mode during Glacial Termination I, and a remote link between Antarctic temperatures and East Asian Summer Monsoon evolution in Japan during Glacial Terminations I and II, which were hitherto unconstrained by high resolution analysis. These findings acknowledge and begin to rationalise spatial and temporal heterogeneities in East Asian Monsoon behaviours by comparison to other records. This work highlights the complexity of the East Asian Monsoon, and the value of long records from contrasting deglacial periods for a better comprehension of this system in the context of anthropogenic climate change

    Information actors beyond modernity and coloniality in times of climate change:A comparative design ethnography on the making of monitors for sustainable futures in Curaçao and Amsterdam, between 2019-2022

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    In his dissertation, Mr. Goilo developed a cutting-edge theoretical framework for an Anthropology of Information. This study compares information in the context of modernity in Amsterdam and coloniality in Curaçao through the making process of monitors and develops five ways to understand how information can act towards sustainable futures. The research also discusses how the two contexts, that is modernity and coloniality, have been in informational symbiosis for centuries which is producing negative informational side effects within the age of the Anthropocene. By exploring the modernity-coloniality symbiosis of information, the author explains how scholars, policymakers, and data-analysts can act through historical and structural roots of contemporary global inequities related to the production and distribution of information. Ultimately, the five theses propose conditions towards the collective production of knowledge towards a more sustainable planet

    The Mars Science Laboratory record of optical depth measurements via solar imaging

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    Acknowledgments We are grateful to the teams that developed, landed, and operated Curiosity on Mars, allowing for the present study. The research was conducted partly at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (80NM0018D0004). MTL was supported via sub-contract 18-1187 from Malin Space Science Systems, Inc. SDG was supported by the MSL Participating Scientist program. JMB was supported by MSL Participating Scientist Grant 80NSSC22K0657. AV-R was supported by the Comunidad de Madrid Project S2018/NMT-4291 (TEC2SPACE-CM). M-PZ was supported by grant PID2019-104205GB-C21 funded by MCIN/AEI/10.13039/501100011033. JM-T was supported by UK Space Agency projects ST/W00190X/1 and ST/V00610X/1.Peer reviewedPostprin

    Graduate Catalog of Studies, 2023-2024

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    Development and Emplacement of Ana Slide, Eivissa Channel, Western Mediterranean Sea

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    Submarine landslides can destroy seafloor infrastructures and generate devastating tsunamis. In spite of decades of research into the functioning of submarine landslides there are still numerous open questions, in particular how different phases of sliding influence each other. Here, we re-analyze Ana Slide—a relatively small (<1 km3) landslide offshore the Balearic Islands, which is unique in the published literature because it is completely imaged by high-resolution 3D reflection seismic data. Ana Slide comprises three domains: (a) a source area that is almost completely evacuated with evidence of headscarp retrogression, (b) an adjacent downslope translational domain representing a by-pass zone for the material that was mobilized in the source area, and (c) the deposit formed by the mobilized material, which accumulated downslope in a sink area and deformed slope sediment. Isochron maps show deep chaotic seismic units underneath the thickest deposits. We infer that the rapid deposition of the landslide material deformed the underlying sediments. A thin stratified sediment unit between three lobes suggests that Ana Slide evolved in two failure stages separated by several tens of thousands of years. This illustrates the problem of over-estimating the volume of mobilized material and under-estimating the complexity even of relatively simple slope failures without high-quality 3D reflection seismic data

    Assessing the Alterations In Berea Sandstone Mechanical Properties Induced by the Permeation of Bentonite Gels of Varying NaCl Concentrations: A Wellbore Strengthening Perspective

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    Lost circulation, which is the loss of drilling fluid into a formation during drilling, is commonly induced by wellbore pressure exceeding that of the fracture initiation pressure (FIP) and fracture propagation pressure (FPP) of the formation. This expensive occurrence can be mitigated by increasing the FIP and FPP by altering the drilling fluid composition, which has a large effect on the mechanical behaviour of rock and subsequently on the FIP and FPP. Bentonite is used both as a base fluid, as well as a lost circulation material. It is therefore imperative to understand the effect that bentonite, at different swelling capacities, has on the mechanical properties of rock to optimise its use in drilling operations to better attenuate lost circulation. In this study, Berea sandstone cores, of four permeability ranges, were permeated with bentonite gels of four NaCl concentrations, using a novel apparatus. Two batches of gel-permeated cores were prepared, one set was allowed to dry, to observe an ageing effect, and the other was kept at 4°C to preserve moisture. The cores were then indented to obtain stress-strain curves. The results of the indentation testing showed a statistically significant increase in peak strength and Young’s modulus in the wet gel-permeated cores relative to the non-permeated samples, whereas the cores with the dried gel displayed a decrease in these properties compared to the control, The dry gel-permeated cores, however, exhibited a significantly longer displacement distance compared to the control, implying these cores take longer to fully fracture apart. In addition to indentation, viscometry experiments were carried out to assess the rheological properties of the gels, this, alongside SEM and CT imaging of the samples, was done in an attempt to understand potential mechanisms behind the alterations in mechanical properties caused by gel permeation. The research carried out shows an initial set of promising results for the use of bentonite gels for wellbore-strengthening applications during drilling. The work undertaken also highlights the need for future research into interactions between non-Newtonian fluids and solids, and the potential that these interactions provide in altering the physicochemical properties of materials

    Neue ErzÀhlformen in dynamischen Bildtechnologien - Formprobleme zwischen PopulÀrkommunikation und autonomer Kunst

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    Jeder Fortschritt, jede Neuerung grĂ¶ĂŸeren Ausmaßes in verschiedenen Medien provoziert nach einer kurzen Phase spielerischen Experiments eine erneute Konsolidierung wie deren Ă€sthetische Reflexion: Diese DualitĂ€t kennen wir spĂ€testens seit den Tagen industrieller Kommunikation als eine Trennung zwischen Massenkommunikation und Kunst. Dies lĂ€sst sich gleichermaßen bei der Entwicklung des zentralperspektivischen Bildes, der frĂŒhen Fotografie oder ganz besonders der Kinematografie beobachten. Nach einer ersten Phase des Kinos der Attraktionen entwickelte sich eine neue und einzigartige Formensprache des Classical Style als konventionalisierte Gestaltungsregel des Films, die zugleich und teilweise in scharfer Opposition verschiedene Gegenbewegungen auslöste oder als deren explizite Reflexion durch individuelle kĂŒnstlerische Formensprachen ĂŒberformt wurde. Aktuell stehen wir vor einer Ă€hnlichen Situation, der Erfindung und Verbreitung dreidimensionaler dynamischer Techniken mit Datenbrille und anderen Technologien, die neue Formen der Virtual Production und damit des ErzĂ€hlens ermöglichen - sogenanntes 'spatial' oder 'environmental storytelling'. Der Band widmet sich diesem neuen ErzĂ€hlen auf drei Ebenen: Raumbild und -ton (Film), Bewegung im Raum (Computerspiel und VR) und Raum als Kontext (AR)

    Investigation of the metabolism of rare nucleotides in plants

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    Nucleotides are metabolites involved in primary metabolism, and specialized metabolism and have a regulatory role in various biochemical reactions in all forms of life. While in other organisms, the nucleotide metabolome was characterized extensively, comparatively little is known about the cellular concentrations of nucleotides in plants. The aim of this dissertation was to investigate the nucleotide metabolome and enzymes influencing the composition and quantities of nucleotides in plants. For this purpose, a method for the analysis of nucleotides and nucleosides in plants and algae was developed (Chapter 2.1), which comprises efficient quenching of enzymatic activity, liquid-liquid extraction and solid phase extraction employing a weak-anionexchange resin. This method allowed the analysis of the nucleotide metabolome of plants in great depth including the quantification of low abundant deoxyribonucleotides and deoxyribonucleosides. The details of the method were summarized in an article, serving as a laboratory protocol (Chapter 2.2). Furthermore, we contributed a review article (Chapter 2.3) that summarizes the literature about nucleotide analysis and recent technological advances with a focus on plants and factors influencing and hindering the analysis of nucleotides in plants, i.e., a complex metabolic matrix, highly stable phosphatases and physicochemical properties of nucleotides. To analyze the sub-cellular concentrations of metabolites, a protocol for the rapid isolation of highly pure mitochondria utilizing affinity chromatography was developed (Chapter 2.4). The method for the purification of nucleotides furthermore contributed to the comprehensive analysis of the nucleotide metabolome in germinating seeds and in establishing seedlings of A. thaliana, with a focus on genes involved in the synthesis of thymidilates (Chapter 2.5) and the characterization of a novel enzyme of purine nucleotide degradation, the XANTHOSINE MONOPHOSPHATE PHOSPHATASE (Chapter 2.6). Protein homology analysis comparing A. thaliana, S. cerevisiae, and H. sapiens led to the identification and characterization of an enzyme involved in the metabolite damage repair system of plants, the INOSINE TRIPHOSPHATE PYROPHOSPHATASE (Chapter 2.7). It was shown that this enzyme dephosphorylates deaminated purine nucleotide triphosphates and thus prevents their incorporation into nucleic acids. Lossof-function mutants senesce early and have a constitutively increased content of salicylic acid. Also, the source of deaminated purine nucleotides in plants was investigated and it was shown that abiotic factors contribute to nucleotide damage.Nukleotide sind Metaboliten, die am PrimĂ€rstoffwechsel und an spezialisierten StoffwechselvorgĂ€ngen beteiligt sind und eine regulierende Rolle bei verschiedenen biochemischen Reaktionen in allen Lebensformen spielen. WĂ€hrend bei anderen Organismen das Nukleotidmetabolom umfassend charakterisiert wurde, ist in Pflanzen vergleichsweise wenig ĂŒber die zellulĂ€ren Konzentrationen von Nukleotiden bekannt. Ziel dieser Dissertation war es, das Nukleotidmetabolom und die Enzyme zu untersuchen, die die Zusammensetzung und Menge der Nukleotide in Pflanzen beeinflussen. Zu diesem Zweck wurde eine Methode zur Analyse von Nukleotiden und Nukleosiden in Pflanzen und Algen entwickelt (Kapitel 2.1), die ein effizientes Stoppen enzymatischer AktivitĂ€t, eine FlĂŒssig-FlĂŒssig-Extraktion und eine Festphasenextraktion unter Verwendung eines schwachen Ionenaustauschers umfasst. Mit dieser Methode konnte das Nukleotidmetabolom von Pflanzen eingehend analysiert werden, einschließlich der Quantifizierung von Desoxyribonukleotiden und Desoxyribonukleosiden mit geringer Abundanz. Die Einzelheiten der Methode wurden in einem Artikel zusammengefasst, der als Laborprotokoll dient (Kapitel 2.2). DarĂŒber hinaus wurde ein Übersichtsartikel (Kapitel 2.3) verfasst, der die Literatur ĂŒber die Analyse von Nukleotiden und die jĂŒngsten technologischen Fortschritte zusammenfasst. Der Schwerpunkt lag hierbei auf Pflanzen und Faktoren, die die Analyse von Nukleotiden in Pflanzen beeinflussen oder behindern, d. h. eine komplexe Matrix, hochstabile Phosphatasen und physikalisch-chemische Eigenschaften von Nukleotiden. Um die subzellulĂ€ren Konzentrationen von Metaboliten zu analysieren, wurde ein Protokoll fĂŒr die schnelle Isolierung hochreiner Mitochondrien unter Verwendung einer AffinitĂ€tschromatographie entwickelt (Kapitel 2.4). Die Methode zur Analyse von Nukleotiden trug außerdem zu einer umfassenden Analyse des Nukleotidmetaboloms in keimenden Samen und in sich etablierenden Keimlingen von A. thaliana bei, wobei der Schwerpunkt auf Genen lag, die an der Synthese von Thymidilaten beteiligt sind (Kapitel 2.5), sowie zu der Charakterisierung eines neuen Enzyms des Purinnukleotidabbaus, der XANTHOSINE MONOPHOSPHATE PHOSPHATASE (Kapitel 2.6). Eine Proteinhomologieanalyse, die A. thaliana, S. cerevisiae und H. sapiens miteinander verglich fĂŒhrte zur Identifizierung und Charakterisierung eines Enzyms, das an der Reparatur von geschĂ€digten Metaboliten in Pflanzen beteiligt ist, der INOSINE TRIPHOSPHATE PYROPHOSPHATASE (Kapitel 2.7). Es konnte gezeigt werden, dass dieses Enzym desaminierte Purinnukleotidtriphosphate dephosphoryliert und so deren Einbau in NukleinsĂ€uren verhindert. Funktionsverlustmutanten altern frĂŒh und weisen einen konstitutiv erhöhten Gehalt an SalicylsĂ€ure auf. Außerdem wurde die Quelle der desaminierten Purinnukleotide in Pflanzen untersucht, und es wurde gezeigt, dass abiotische Faktoren zur NukleotidschĂ€digung beitragen
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