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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
111

Factorisation of beams in van der Meer scans and measurements of the phi star distribution of Z to e+e- events in pp collisions at square root of s = 8 TeV with the ATLAS detector

Webb, Samuel Nathan January 2015 (has links)
Two analyses of data recorded in proton-proton collisions at the ATLAS detector in 2012 are presented in this thesis. The first pertains to the beam separation (van der Meer) scans required to calibrate the absolute luminosity. An estimate is made for the size of the correction needed to the standard van der Meer calibration method, which assumes that the proton bunch density profiles are factorisable. This is done by observing and modelling the evolution of various beam spot phenomena during the separation scans. The second analysis described is a series of measurements of the Z/gamma cross-section, differential in the phi star observable, for different ranges of the boson invariant mass and absolute rapidity. In particular the events in which the boson decays to electron-positron pairs are considered. The phi star observable is defined in terms of the well-measured lepton directions and enables a probe of initial state gluon radiation in the non-perturbative regime of QCD.
112

Vliv vibračního tréninku na Power Plate na výkonnost člověka / Effect of vibration training on the Power Plate on human performance

Vančura, Jakub January 2012 (has links)
Title: The effect of vibration training on the Power Plate on human performance Objectives: Following the training schedule, the groups will be tested and results compared; as well as the study results revealed. Methods: In my diploma work I set out to test 16 individuals, who undergo an 8 week training program on the Power Plate vibration technology machine. Eight women and eight men will be separated into two groups. The first group (four men, and four women) will exercise on a vibrating machine, whereas the second group will exercise on the machine without any vibrational stimulus. Explosive agilities (Boscuv test - longest air-time). Reaction speed (auditory reaction to a beep signal, and reactometer test for both the upper and lower limbs. Flexibility (testing a sitting hamstring reach). Antropometric testing (Body mass, girth, active muscle weight, BMI). In order to be able to judge development, as well as to gauge kinesiologic abilities, I applied a number of special tests. The results of individual results are noted in the tables. The T-test was applied as a statistics method. Results: Through repeated measure, it was discovered that the group training on the Power Plate achieved improvements in three out of four tests. Two tests showed above average results against standard, especially in...
113

A poética do detalhe no episódio da lanterna mágica em À la recherche du temps perdu / The poetic detail in the magic lantern episode of A la recherche du temps perdu

Leandro, João Gonçalves Vilela 07 April 2015 (has links)
A fortuna crítica de À la recherche du temps perdu sempre teve como um dos seus principais motes a relação da obra com outras artes, ou seja, uma construção estética baseada em uma relação de homologia estrutural com outros sistemas artísticos, dentre eles a música, a arquitetura, a própria literatura e a pintura. Essa construção faz com que a obra venha constantemente acompanhada do epíteto de museu imaginário. Especificamente, o nome do pintor holandês Johannes Ver Meer tem um lugar privilegiado na estética proustiana. Entretanto, nem todas as telas são mencionadas ao longo da narrativa. Somada a isso, a tessitura da escritura de Marcel Proust revela-se como um saber fortemente indiciário. Assim, a partir de índices que percorrem epístolas de Proust, textos críticos e a própria narrativa de À la recherche du temps perdu, esta tese cujo recorte de leitura é especificamente o episódio da lanterna mágica e seus desdobramentos defende que uma das telas de Ver Meer, a saber, A arte da pintura, é uma ausência epistêmica que, no entanto, faz-se presente, deixando inscritos na obra seus efeitos de significação. A fim de compreendermos essa presença-ausente, esta tese recorre ao conceito de letra, conforme o ensino de Jacques Lacan, os textos freudianos nos quais esse conceito estava em latência e os esclarecimentos e avanços feitos por Jacques Derrida, especificamente em seus textos da década de sessenta do século passado. Por efeitos de significação, concebe-se a ideia de que A arte da pintura realiza-se como uma ideia ausente, mas pungente no que tange aos efeitos estéticos de esmero do detalhe e dos processos descritivos, implicando uma relação de similitude entre o narrador em seu quarto, em lincipit de À la recherche du temps perdu e no episódio da lanterna mágica, e um artista em seu ateliê, presente na tela de Ver Meer, que incidirá em uma poética do detalhe. / The critical fortune of À la Recherche du Temps Perdu has always had, as one of its main threads, the relationship of work with other art forms, in other words, an aesthetic construction based on a relationship of structural homology with other Arts, including music, architecture, literature itself and painting. This ensures that the work is constantly accompanied by the epithet of the imaginary museum. Specifically, the name of the Dutch painter Johannes Ver Meer has a privileged place in the Proustian aesthetic. Nevertheless, not all canvases are mentioned during the narrative. Added to this, the tone of the Marcel Proust text reveals itself as a clear, evidentiary wisdom. Therefore, from indices that permeate the Proust missives, critical texts and the narrative of À la Recherche du Temps Perdu, this thesis, the scope of which is limited specifically to the episode of the Magic Lantern and its ramifications, argues that one of Ver Meers canvases, namely that of the Art of Painting, is epistemically absent, however it makes its presence felt through its effects of significance on the piece. In order to understand this absent-presence, this thesis uses the concept of the letter, according to the teachings of Jacques Lacan, Freudian texts in which this concept was latent, and in the clarifications and advances made by Jacques Derrida in his writings of the 1960s. For purpose of meaning, one has conceived the idea that The Art of Painting be like a missing yet poignant idea touching the aesthetic effects of minute detail and of the descriptive processes, implying an affinity in relationship between the narrator in his chamber, in l\'incipit of la Recherche du Temps Perdu and the episode of the Magic Lantern, and the artist in his studio, present on Ver Meers canvas, reflected in a poetic detail.
114

Current status and long-term insights into the western Dead Sea groundwater system using multi-sensoral remote sensing

Mallast, Ulf 11 October 2013 (has links) (PDF)
Arid regions, that have a terrestrial share of 30 %, heavily rely on groundwater for do-mestic, industrial and irrigation purposes. The reliance on groundwater has partly turned into a dependency in areas where the increasing population number and the expansion of irrigated agricultural areas demand more groundwater than is naturally replenished. Yet, spatial and temporal information on groundwater are often scarce induced by the facts that groundwater is given a low priority in many national budgets and numerous (semi-) arid regions in the world encompass large and inaccessible areas. Hence, there is an urgent need to provide low-cost alternatives that in parallel cover large spatial and temporal scales to gain information on the groundwater system. Remote sensing holds a tremendous potential to represent this alternative. The main objective of this thesis is the improvement of existing and the development of novel remote sensing applications to infer information on the scarce but indispensable resource groundwater at the example of the Dead Sea. The background of these de-velopments relies mainly on freely available satellite data sets. I investigate 1) the pos-sibility to infer potential groundwater flow-paths from digital elevation models, 2) the applicability of multi-temporal thermal satellite data to identify groundwater discharge locations, 3) the suitability of multi-temporal thermal satellite data to derive information on the long-term groundwater discharge behaviour, and 4) the differences of thermal data in terms of groundwater discharge between coarse-scaled satellite data and fine-scaled airborne data including a discharge quantification approach. 1) I develop a transparent, reproducible and objective semi-automatic approach us-ing a combined linear filtering and object based classification approach that bases on a medium resolution (30 m ground sampling distance) digital elevation model to extract lineaments. I demonstrate that the obtained lineaments have both, a hydrogeological and groundwater significance, that allow the derivation of potential groundwater flow-paths. These flow-paths match results of existing groundwater flow models remarkably well that validate the findings and shows the possibility to infer potential groundwater flow-paths from remote sensing data. 2) Thermal satellite data enable to identify groundwater discharge into open water bodies given a temperature contrast between groundwater and water body. Integrating a series of thermal data from different periods into a multi-temporal analysis accounts for the groundwater discharge intermittency and hence allows obtaining a representa-tive discharge picture. I analyse the constraints that arise with the multi-temporal anal-ysis (2000-2002) and show that ephemeral surface-runoff causes similar thermal anomalies as groundwater. To exclude surface-runoff influenced data I develop an au-tonomously operating method that facilitates the identification. I calculate on the re-maining surface-runoff uninfluenced data series different statistical measures on a per pixel basis to amplify groundwater discharge induced thermal anomalies. The results reveal that the range and standard deviation of the data series perform best in terms of anomaly amplification and spatial correspondence to in-situ determined spring dis-charge locations. I conclude on the reason that both mirror temperature variability that is stabilized and therefore smaller at areas where spatio-temporal constant groundwater discharge occurs. 3) The application of the before developed method on a thermal satellite data set spanning the years 2000 to 2011 enables to localise specific groundwater discharge sites and to semi-quantitatively analyse the temporal variability of the thermal anomalies (termed groundwater affected area - GAA). I identify 37 groundwater discharge sites along the entire Dead Sea coastline that refine the so far coarsely given spring areas to specific locations. All spatially match independent in-situ groundwater discharge observations and additionally indicate 15 so far unreported discharge sites. Comparing the variability of the GAA extents over time to recharge behaviour reveals analogous curve progressions with a time-shift of two years. This observation suggests that the thermally identified GAAs directly display the before only assumed groundwater discharge volume. This finding provides a serious alternative to monitor groundwater discharge over large temporal and spatial scales that is relevant for different scientific communities. From the results I furthermore conclude to observe the before only assumed and modelled groundwater discharge share from flushing of old brines during periods with an above average Dead Sea level drop. This observation implies the need to not only consider discharge from known terrestrial and submarine springs, but also from flushing of old-brines in order to calculate the total Dead Sea water budget. 4) I present a complementary airborne thermal data set recorded in 01/2011 over the north-western part of the Dead Sea coast. The higher spatial resolution allows to refine the satellite-based GAA to 72 specific groundwater discharge sites and even to specify the so far unknown abundance of submarine springs to six sites with a share of <10 % to the total groundwater discharge. A larger contribution stems from newly iden-tified seeping spring type (24 sites) where groundwater emerges diffusively either ter-restrial or submarine close to the land/water interface with a higher share to the total discharge than submarine springs provide. The major groundwater contribution origi-nates from the 42 identified terrestrial springs. For this spring type, I demonstrate that 93 % of the discharge volume can be modelled with a linear ordinary least square re-gression (R2=0.88) based on the thermal plume extents and in-situ measured discharge volumes from the Israel Hydrological Service. This result implies the possibility to determine discharge volumes at unmonitored sites along the Dead Sea coast as well that can provide a complete physically-based picture of groundwater discharge magni-tude to the Dead Sea for the first time.
115

A poética do detalhe no episódio da lanterna mágica em À la recherche du temps perdu / The poetic detail in the magic lantern episode of A la recherche du temps perdu

João Gonçalves Vilela Leandro 07 April 2015 (has links)
A fortuna crítica de À la recherche du temps perdu sempre teve como um dos seus principais motes a relação da obra com outras artes, ou seja, uma construção estética baseada em uma relação de homologia estrutural com outros sistemas artísticos, dentre eles a música, a arquitetura, a própria literatura e a pintura. Essa construção faz com que a obra venha constantemente acompanhada do epíteto de museu imaginário. Especificamente, o nome do pintor holandês Johannes Ver Meer tem um lugar privilegiado na estética proustiana. Entretanto, nem todas as telas são mencionadas ao longo da narrativa. Somada a isso, a tessitura da escritura de Marcel Proust revela-se como um saber fortemente indiciário. Assim, a partir de índices que percorrem epístolas de Proust, textos críticos e a própria narrativa de À la recherche du temps perdu, esta tese cujo recorte de leitura é especificamente o episódio da lanterna mágica e seus desdobramentos defende que uma das telas de Ver Meer, a saber, A arte da pintura, é uma ausência epistêmica que, no entanto, faz-se presente, deixando inscritos na obra seus efeitos de significação. A fim de compreendermos essa presença-ausente, esta tese recorre ao conceito de letra, conforme o ensino de Jacques Lacan, os textos freudianos nos quais esse conceito estava em latência e os esclarecimentos e avanços feitos por Jacques Derrida, especificamente em seus textos da década de sessenta do século passado. Por efeitos de significação, concebe-se a ideia de que A arte da pintura realiza-se como uma ideia ausente, mas pungente no que tange aos efeitos estéticos de esmero do detalhe e dos processos descritivos, implicando uma relação de similitude entre o narrador em seu quarto, em lincipit de À la recherche du temps perdu e no episódio da lanterna mágica, e um artista em seu ateliê, presente na tela de Ver Meer, que incidirá em uma poética do detalhe. / The critical fortune of À la Recherche du Temps Perdu has always had, as one of its main threads, the relationship of work with other art forms, in other words, an aesthetic construction based on a relationship of structural homology with other Arts, including music, architecture, literature itself and painting. This ensures that the work is constantly accompanied by the epithet of the imaginary museum. Specifically, the name of the Dutch painter Johannes Ver Meer has a privileged place in the Proustian aesthetic. Nevertheless, not all canvases are mentioned during the narrative. Added to this, the tone of the Marcel Proust text reveals itself as a clear, evidentiary wisdom. Therefore, from indices that permeate the Proust missives, critical texts and the narrative of À la Recherche du Temps Perdu, this thesis, the scope of which is limited specifically to the episode of the Magic Lantern and its ramifications, argues that one of Ver Meers canvases, namely that of the Art of Painting, is epistemically absent, however it makes its presence felt through its effects of significance on the piece. In order to understand this absent-presence, this thesis uses the concept of the letter, according to the teachings of Jacques Lacan, Freudian texts in which this concept was latent, and in the clarifications and advances made by Jacques Derrida in his writings of the 1960s. For purpose of meaning, one has conceived the idea that The Art of Painting be like a missing yet poignant idea touching the aesthetic effects of minute detail and of the descriptive processes, implying an affinity in relationship between the narrator in his chamber, in l\'incipit of la Recherche du Temps Perdu and the episode of the Magic Lantern, and the artist in his studio, present on Ver Meers canvas, reflected in a poetic detail.
116

Identification of water origin and water-rock interaction in a complex multi-aquifer system in the Dead Sea Rift by applying chemistry and isotopes

Wilske, Cornelia Maria 14 January 2020 (has links)
Die vorliegende Studie befasst sich mit einer hydrochemischen Untersuchung des Aquifersystems auf der Westseite des Toten Meeres. Für die Untersuchungen der Grundwasserressourcen der kreidezeitlichen Grundwasserleiter, insbesondere Grundwasserherkunft, Mischprozesse, Identifizierung von Wasser-Gesteins- Wechselwirkungen, Datierung von Grundwasseraltersbereichen, Identifizierung der Herkunft des Quellen an der Küste des Toten Meeres und Abtrennung quartärer Grundwassermuster, wurde eine Tracerkombination auf Wasser- und Gesteinsproben angewendet. Die hier vorgestellte Multitracer-Methodik ist auch in anderen datenarmen Gebieten mit komplexer Hydrogeologie (Karst oder Störungen) unter anthropogenem Einfluss anwendbar. / The present study deals with a hydrochemical investigation of the aquifer system on the western side of the Dead Sea. To examine the groundwater resources of the Cretaceous aquifer, particularly groundwater origins, mixing processes, identification of water-rock interaction, dating of groundwater age ranges in the aquifers and identification of spring water origins at the Dead Sea coast and separation of Quaternary groundwater patterns, a combination of tracer is applied on water and rock samples. The multi-tracer method presented here is also applicable in other data-poor areas with complex hydrogeology (karst or fracture) under anthropogenic influence.
117

Current status and long-term insights into the western Dead Sea groundwater system using multi-sensoral remote sensing

Mallast, Ulf 23 July 2013 (has links)
Arid regions, that have a terrestrial share of 30 %, heavily rely on groundwater for do-mestic, industrial and irrigation purposes. The reliance on groundwater has partly turned into a dependency in areas where the increasing population number and the expansion of irrigated agricultural areas demand more groundwater than is naturally replenished. Yet, spatial and temporal information on groundwater are often scarce induced by the facts that groundwater is given a low priority in many national budgets and numerous (semi-) arid regions in the world encompass large and inaccessible areas. Hence, there is an urgent need to provide low-cost alternatives that in parallel cover large spatial and temporal scales to gain information on the groundwater system. Remote sensing holds a tremendous potential to represent this alternative. The main objective of this thesis is the improvement of existing and the development of novel remote sensing applications to infer information on the scarce but indispensable resource groundwater at the example of the Dead Sea. The background of these de-velopments relies mainly on freely available satellite data sets. I investigate 1) the pos-sibility to infer potential groundwater flow-paths from digital elevation models, 2) the applicability of multi-temporal thermal satellite data to identify groundwater discharge locations, 3) the suitability of multi-temporal thermal satellite data to derive information on the long-term groundwater discharge behaviour, and 4) the differences of thermal data in terms of groundwater discharge between coarse-scaled satellite data and fine-scaled airborne data including a discharge quantification approach. 1) I develop a transparent, reproducible and objective semi-automatic approach us-ing a combined linear filtering and object based classification approach that bases on a medium resolution (30 m ground sampling distance) digital elevation model to extract lineaments. I demonstrate that the obtained lineaments have both, a hydrogeological and groundwater significance, that allow the derivation of potential groundwater flow-paths. These flow-paths match results of existing groundwater flow models remarkably well that validate the findings and shows the possibility to infer potential groundwater flow-paths from remote sensing data. 2) Thermal satellite data enable to identify groundwater discharge into open water bodies given a temperature contrast between groundwater and water body. Integrating a series of thermal data from different periods into a multi-temporal analysis accounts for the groundwater discharge intermittency and hence allows obtaining a representa-tive discharge picture. I analyse the constraints that arise with the multi-temporal anal-ysis (2000-2002) and show that ephemeral surface-runoff causes similar thermal anomalies as groundwater. To exclude surface-runoff influenced data I develop an au-tonomously operating method that facilitates the identification. I calculate on the re-maining surface-runoff uninfluenced data series different statistical measures on a per pixel basis to amplify groundwater discharge induced thermal anomalies. The results reveal that the range and standard deviation of the data series perform best in terms of anomaly amplification and spatial correspondence to in-situ determined spring dis-charge locations. I conclude on the reason that both mirror temperature variability that is stabilized and therefore smaller at areas where spatio-temporal constant groundwater discharge occurs. 3) The application of the before developed method on a thermal satellite data set spanning the years 2000 to 2011 enables to localise specific groundwater discharge sites and to semi-quantitatively analyse the temporal variability of the thermal anomalies (termed groundwater affected area - GAA). I identify 37 groundwater discharge sites along the entire Dead Sea coastline that refine the so far coarsely given spring areas to specific locations. All spatially match independent in-situ groundwater discharge observations and additionally indicate 15 so far unreported discharge sites. Comparing the variability of the GAA extents over time to recharge behaviour reveals analogous curve progressions with a time-shift of two years. This observation suggests that the thermally identified GAAs directly display the before only assumed groundwater discharge volume. This finding provides a serious alternative to monitor groundwater discharge over large temporal and spatial scales that is relevant for different scientific communities. From the results I furthermore conclude to observe the before only assumed and modelled groundwater discharge share from flushing of old brines during periods with an above average Dead Sea level drop. This observation implies the need to not only consider discharge from known terrestrial and submarine springs, but also from flushing of old-brines in order to calculate the total Dead Sea water budget. 4) I present a complementary airborne thermal data set recorded in 01/2011 over the north-western part of the Dead Sea coast. The higher spatial resolution allows to refine the satellite-based GAA to 72 specific groundwater discharge sites and even to specify the so far unknown abundance of submarine springs to six sites with a share of <10 % to the total groundwater discharge. A larger contribution stems from newly iden-tified seeping spring type (24 sites) where groundwater emerges diffusively either ter-restrial or submarine close to the land/water interface with a higher share to the total discharge than submarine springs provide. The major groundwater contribution origi-nates from the 42 identified terrestrial springs. For this spring type, I demonstrate that 93 % of the discharge volume can be modelled with a linear ordinary least square re-gression (R2=0.88) based on the thermal plume extents and in-situ measured discharge volumes from the Israel Hydrological Service. This result implies the possibility to determine discharge volumes at unmonitored sites along the Dead Sea coast as well that can provide a complete physically-based picture of groundwater discharge magni-tude to the Dead Sea for the first time.:1 Introduction 1.1 Remote sensing applications on groundwater 1.1.1 Classical aspects 1.1.2 Modern aspects 1.2 Motivation and main objectives 1.3 Why the western catchment of the Dead Sea? 1.4 Overview 2 The western catchment of the Dead Sea 2.1 Geological and Structural Overview 2.2 Groundwater system 2.3 Groundwater inputs 2.4 Dead Sea 3 Groundwater flow-paths 3.1 Prologue 4 Method development for groundwater discharge identification 4.1 Prologue 5 Localisation and temporal variability of groundwater discharge 5.1 Prologue 6 Qualitative and quantitative refinement of groundwater discharge 6.1 Prologue 7 Conclusion and Outlook 7.1 Main results and implications 7.2 Outlook References Appendix
118

Paleoenvironmental changes in the Black Sea region during the last 26,000 years : a multi-proxy study of lacustrine sediments from the western Black Sea

Kwiecien, Olga January 2008 (has links)
Paleoenvironmental records provide ample information on the Late Quaternary climatic evolution. Due to the great diversity of continental mid-latitude environments the synthetic picture of the past mid-latitudinal climate changes is, however, far from being complete. Owing to its significant size and landlocked setting the Black Sea constitutes a perfect location to study patterns and mechanisms of climate change along the continental interior of Central and Eastern Europe and Asia Minor. Presently, the southern drainage area of the Black Sea is characterized by a Mediterranean-type climate while the northern drainage is under the influence of Central and Northern European climate. During the Last Glacial a decrease in the global sea level disconnected the Black Sea from the Mediterranean Sea transforming it into a giant closed lake. At that time atmospheric precipitation and related with it river run-off were the most important factors driving sediment supply and water chemistry of the Black ‘Lake’. Therefore studying properties of the Black Sea sediments provides important information on the interactions and development of the Mediterranean and Central and North European climate in the past. One significant outcome of my thesis is an improved chronostraphigraphical framework for the glacial lacustrine unit of the Black Sea sediment cores, which allowed to refine the environmental history of the Black Sea region and enabled a reliable correlation with data from other marine and terrestrial archives. Data gathered along a N-S transect presented on a common time scale revealed coherent changes in the basin and its surrounding. During the glacial, the southward-shifted Polar Front reduced moisture transport to the northern drainage of the Black Sea and let the southern drainage become dominant in freshwater and sediment supply into the basin. Changes in NW Anatolian precipitation reconstructed from the variability of the terrigenous input imply that during the glacial the regional rainfall variability was strongly influenced by Mediterranean sea surface temperatures and decreased in response to the cooling associated with the North Atlantic Heinrich Events H1 and H2. In contrast to regional precipitation changes, the hydrological properties of the Black Sea remained relatively stable under full glacial conditions. First significant modification in the freshwater/sediment sources reconstructed from changes in the sediment composition, lithology, and 18O of ostracods took place at around 16.4 cal ka BP, simultaneous to the early deglacial northward retreat of the oceanic and atmospheric polar fronts. Meltwater pulses, most probably derived from the disintegrating European ice sheets, changed the isotopic composition of the Black Sea and increased the supply from northern sediment sources. While these changes signalized a mitigation of the Northern European and Mediterranean climate, a decisive increase in local temperature was indicated only later at the transition from the Oldest Dryas to the Bølling around 14.6 cal ka BP. At that time the warming of the Black Sea surface initiated massive phytoplankton blooms, which in turn, induced the precipitation of inorganic carbonates. This biologically triggered process significantly changed the water chemistry and was recorded by simultaneous shifts in the elemental composition of ostracod shells and in the isotopic composition of the inorganically-precipitated carbonates. Starting with the B/A warming and continuing through the YD cold interval and the Early Holocene warming, the Black Sea temperature signal corresponds to the precipitation and temperature changes recorded in the wider Mediterranean region. Early Holocene conditions, similar to those of the Bølling/Allerød, were punctured by the marine inflow from the Mediterranean at ~ 9.3 cal ka BP, which terminated the lacustrine phase of the Black Sea and had a substantial impact on the chemical and physical properties of its water. / Aus Paläoumweltdaten lassen sich detaillierte Informationen über die spätquartäre Klimaentwicklung gewinnen. Für die kontinentalen mittleren Breiten ist das Gesamtbild der Klimaänderungen während dieses Zeitraumes aufgrund seiner Vielfältigkeit allerdings noch immer unvollständig. Eine ideale Loka-tion, das Muster und die Mechanismen der Klimaänderungen in Osteuropa und Kleinasien zu untersu-chen, ist das Schwarze Meer mit seiner bedeutenden Größe und seiner kontinentalen Lage. Gegenwärtig ist das südliche Einzugsgebiet des Schwarzen Meeres durch ein mediterranes Klima ge-prägt, während die nördlichen Regionen von zentral- bzw. nordeuropäischem Klima beeinflusst werden. Als im letzten Glazial der Meeresspiegel so stark sank, dass das Schwarze Meer vom Mittelmeer abge-trennt und zu einem großen, abflusslosen See wurde, waren der atmosphärische Niederschlag und der damit verbundene Abfluss die wesentlichen Steuerfaktoren für Sedimenteintrag und Wasserchemie des Schwarzen „Sees“. Deshalb liefert die Untersuchung der Sedimente des Schwarzen Meeres wichtige Informationen über die früheren Zusammenhänge sowie die Entwicklung von mediterranem und zentral- bzw. nordeuropäischem Klima. Das bedeutsamste Ergebnis meiner Doktorarbeit ist ein verbessertes Altersmodell für Sedimentkerne aus dem westlichen Schwarzen Meer; dieses erlaubt eine genauere Rekonstruktion der Entwicklungsge-schichte dieses Binnenmeeres und seiner Umgebung und ermöglicht einen fundierten Vergleich mit an-deren marinen und terrestrischen Archiven. Daten, die entlang eines N-S Transektes im westlichen Be-reich des Schwarzen Meeres erfasst wurden und auf einer gemeinsamen Zeitskala dargestellt werden, lassen die folgenden zusammenhängenden Entwicklungen im Becken und seiner Umgebung erkennen: Während des Glazials war der Feuchtigkeitstransport zum nördlichen Einzugsgebiet des Schwarzen Meeres aufgrund der südwärts verlagerten Polarfront vermindert, so dass Süßwasser und Sedimente vor-rangig aus dem südlichen Einzugsgebiet in das Becken gelangten. Die Rekonstruktion von Nieder-schlagsänderungen mit Hilfe von Schwankungen des terrigenen Eintrags zeigt, dass der regionale Nie-derschlag im Glazial stark von den Wasseroberflächentemperaturen des Mittelmeeres beeinflusst wurde und als Folge der Abkühlung während der nordatlantischen Heinrich-Ereignisse H1 und H2 abnahm. Im Gegensatz dazu blieb das Schwarze Meer während des Hochglazials hydrologisch relativ stabil. Die Sedimentzusammensetzung, Lithologie und δ18O-Werte von Ostracoden zeigen, dass erste signifi-kante Änderungen im Frischwasser- und Sedimenteintrag zeitgleich mit dem frühglazialen nordwärtigen Rückzug der ozeanischen und atmosphärischen Polarfronten um 16.4 cal ka BP auftraten. Der Schmelz-wassereintrag abschmelzender europäischer Eisflächen veränderte die Isotopenzusammensetzung des Wassers und erhöhte die Sedimentzufuhr aus den nördlichen Quellen. Während diese Änderungen auf ein bereits milderes Klima in Nordeuropa und im Mittelmeerraum hin-deuten, zeigt sich ein Anstieg der lokalen Temperaturen erst während des Übergangs von der Älteren Dryas zum Bølling/Allerød um etwa 14.6 cal. ka BP. Zu diesem Zeitpunkt führte ein wahrscheinlicher Anstieg der Wasseroberflächentemperaturen im Schwarzen Meer zu einem massiven Phytoplankton-wachstum, welcher die Ausfällung anorganischen Karbonats zur Folge hatte. Dieser biologisch ausgelös-te Prozess veränderte maßgeblich die Wasserchemie und spiegelt sich in simultanen Veränderungen der Elementzusammensetzung von Ostracoden und der Isotopenzusammensetzung von anorganisch ausge-fälltem Karbonat wieder. Beginnend mit dem Bølling/Allerød, durch die Jüngere Dryas Kälteperiode und die frühholozäne Erwärmung hindurch, deckt sich das Temperatursignal des Schwarzen Meeres mit den Niederschlags- und Temperaturänderungen des weiteren Mittelmeerraumes. Das Frühholozän war, ähnlich wie das Bølling/Allerød, durch das Einströmen salzhaltigen Meerwassers aus dem Mittelmeer gekennzeichnet (~9.5 cal. ka BP), welches die lakustrine Phase des Schwarzen Mee-res beendete und einen erheblichen Einfluss auf seine chemischen und physikalischen Wassereigen-schaften ausübte.
119

Time-dependent occurrence rates of large earthquakes in the Dead Sea fault zone and applications to probabilistic seismic hazard assessments

Hakimhashemi, Amir Hossein January 2009 (has links)
Die relativ hohe seismische Aktivität der Tote-Meer-Störungszone (Dead Sea Fault Zone - DSFZ) ist mit einem hohen Gefahrenpotential verbunden, welches zu einem erheblichen Erdbebenrisiko für die Ballungszentren in den Ländern Syrien, Libanon, Palästina, Jordanien und Israel führt. Eine Vielzahl massiver, zerstörerischer Erdbeben hat sich in diesem Raum in den letzten zwei Jahrtausenden ereignet. Ihre Wiederholungsrate zeigt Anzeichen für eine zeitliche Abhängigkeit, insbesondere wenn lange Zeiträume in Betracht gezogen werden. Die Berücksichtigung der zeitlichen Abhängigkeit des Auftretens von Erdbeben ist für eine realistische seismische Gefährdungseinschätzung von großer Bedeutung. Ziel der vorliegenden Arbeit ist es, anhand des zeitabhängigen Auftretens von Erdbeben eine robuste wahrscheinlichkeitstheoretische seismische Gefährdungseinschätzung am Beispiel der DSFZ zu entwickeln. Mittels dieser Methode soll die zeitliche Abhängigkeit des Auftretens von großen Erdbeben (Mw ≥ 6) untersucht und somit eine Gefährdungseinschätzung für das Untersuchungsgebiet getroffen werden. Primär gilt es zu prüfen, ob das Auftreten von großen Erdbeben tatsächlich einer zeitlichen Abhängigkeit unterliegt und wenn ja, inwiefern diese bestimmt werden kann. Zu diesem Zweck werden insgesamt vier zeitabhängige statistische Verteilungen (Weibull, Gamma, Lognormal und Brownian Passage Time (BPT)) sowie die zeitunabhängige Exponentialverteilung (Poisson-Prozess) getestet. Zur Abschätzung der jeweiligen Modellparameter wird eine modifizierte Methode der gewichteten Maximum-Likelihood-Schätzung (MLE) verwendet. Um einzuschätzen, ob die Wiederholungsrate von Erdbeben einer unimodalen oder multimodalen Form folgt, wird ein nichtparametrischer Bootstrap-Test für Multimodalität durchgeführt. Im Falle einer multimodalen Form wird neben der MLE zusätzlich eine Erwartungsmaximierungsmethode (EM) herangezogen. Zur Auswahl des am besten geeigneten Modells wird zum einem das Bayesschen Informationskriterium (BIC) und zum anderen der modifizierte Kolmogorow-Smirnow-Goodness-of-Fit-Test angewendet. Abschließend werden mittels der Bootstrap-Methode die Konfidenzintervalle der geschätzten Parameter berechnet. Als Datengrundlage werden Erdbeben mit Mw ≥ 6 seit dem Jahre 300 n. Chr. herangezogen. Das Untersuchungsgebiet erstreckt sich von 29.5° N bis 37° N und umfasst ein ca. 40 km breites Gebiet entlang der DSFZ. Aufgrund der seismotektonischen Situation im Untersuchungsgebiet wird zwischen einer südlichen, zentralen und nördlichen Subzone unterschieden. Dabei kann die südliche Subzone aus Mangel an Daten nicht für die Analysen herangezogen werden. Die Ergebnisse für die zentrale Subzone zeigen keinen signifikanten multimodalen Verlauf der Wiederholungsrate von Erdbeben. Des Weiteren ist kein signifikanter Unterschied zwischen den zeitabhängigen und dem zeitunabhängigem Modell zu verzeichnen. Da das zeitunabhängige Modell vergleichsweise einfach interpretierbar ist, wird die Wiederholungsrate von Erdbeben in dieser Subzone unter Annahme der Exponentialverteilungs-Hypothese abgeschätzt. Sie wird demnach als zeitunabhängig betrachtet und beträgt 9.72 * 10-3 Erdbeben (mit Mw ≥ 6) pro Jahr. Einen besonderen Fall stellt die nördliche Subzone dar. In diesem Gebiet tritt im Durchschnitt alle 51 Jahre ein massives Erdbeben (Mw ≥ 6) auf. Das letzte Erdbeben dieser Größe ereignete sich 1872 und liegt somit bereits 137 Jahre zurück. Somit ist in diesem Gebiet ein Erdbeben dieser Stärke überfällig. Im statistischen Mittel liegt die Zeit zwischen zwei Erdbeben zu 96% unter 137 Jahren. Zudem wird eine deutliche zeitliche Abhängigkeit der Erdbeben-Wiederauftretensrate durch die Ergebnisse der in der Arbeit neu entwickelten statistischen Verfahren bestätigt. Dabei ist festzustellen, dass die Wiederholungsrate insbesondere kurz nach einem Erdbeben eine sehr hohe zeitliche Abhängigkeit aufweist. Am besten repräsentiert werden die seismischen Bedingungen in der genannten Subzone durch ein bi-modales Weibull-Weibull-Modell. Die Wiederholungsrate ist eine glatte Zeitfunktion, welche zwei Häufungen von Datenpunkten in der Zeit nach dem Erdbeben zeigt. Dabei umfasst die erste Häufung einen Zeitraum von 80 Jahren, ausgehend vom Zeitpunkt des jeweiligen Bebens. Innerhalb dieser Zeitspanne ist die Wiederholungsrate extrem zeitabhängig. Die Wiederholungsrate direkt nach einem Beben ist sehr niedrig und steigert sich in den folgenden 10 Jahren erheblich bis zu einem Maximum von 0.024 Erdbeben/Jahr. Anschließend sinkt die Rate und erreicht ihr Minimum nach weiteren 70 Jahren mit 0.0145 Erdbeben/Jahr. An dieses Minimum schließt sich die zweite Häufung von Daten an, dessen Dauer abhängig von der Erdbebenwiederholungszeit ist. Innerhalb dieses Zeitfensters nimmt die Erdbeben-Wiederauftretensrate annähernd konstant um 0.015 Erdbeben/Jahr zu. Diese Ergebnisse bilden die Grundlage für eine zeitabhängige probabilistische seismische Gefährdungseinschätzung (PSHA) für die seismische Quellregion, die den nördlichen Raum der DSFZ umfasst. / The seismicity of the Dead Sea fault zone (DSFZ) during the last two millennia is characterized by a number of damaging and partly devastating earthquakes. These events pose a considerable seismic hazard and seismic risk to Syria, Lebanon, Palestine, Jordan, and Israel. The occurrence rates for large earthquakes along the DSFZ show indications to temporal changes in the long-term view. The aim of this thesis is to find out, if the occurrence rates of large earthquakes (Mw ≥ 6) in different parts of the DSFZ are time-dependent and how. The results are applied to probabilistic seismic hazard assessments (PSHA) in the DSFZ and neighboring areas. Therefore, four time-dependent statistical models (distributions), including Weibull, Gamma, Lognormal and Brownian Passage Time (BPT), are applied beside the exponential distribution (Poisson process) as the classical time-independent model. In order to make sure, if the earthquake occurrence rate follows a unimodal or a multimodal form, a nonparametric bootstrap test of multimodality has been done. A modified method of weighted Maximum Likelihood Estimation (MLE) is applied to estimate the parameters of the models. For the multimodal cases, an Expectation Maximization (EM) method is used in addition to the MLE method. The selection of the best model is done by two methods; the Bayesian Information Criterion (BIC) as well as a modified Kolmogorov-Smirnov goodness-of-fit test. Finally, the confidence intervals of the estimated parameters corresponding to the candidate models are calculated, using the bootstrap confidence sets. In this thesis, earthquakes with Mw ≥ 6 along the DSFZ, with a width of about 20 km and inside 29.5° ≤ latitude ≤ 37° are considered as the dataset. The completeness of this dataset is calculated since 300 A.D. The DSFZ has been divided into three sub zones; the southern, the central and the northern sub zone respectively. The central and the northern sub zones have been investigated but not the southern sub zone, because of the lack of sufficient data. The results of the thesis for the central part of the DSFZ show that the earthquake occurrence rate does not significantly pursue a multimodal form. There is also no considerable difference between the time-dependent and time-independent models. Since the time-independent model is easier to interpret, the earthquake occurrence rate in this sub zone has been estimated under the exponential distribution assumption (Poisson process) and will be considered as time-independent with the amount of 9.72 * 10-3 events/year. The northern part of the DSFZ is a special case, where the last earthquake has occurred in 1872 (about 137 years ago). However, the mean recurrence time of Mw ≥ 6 events in this area is about 51 years. Moreover, about 96 percent of the observed earthquake inter-event times (the time between two successive earthquakes) in the dataset regarding to this sub zone are smaller than 137 years. Therefore, it is a zone with an overdue earthquake. The results for this sub zone verify that the earthquake occurrence rate is strongly time-dependent, especially shortly after an earthquake occurrence. A bimodal Weibull-Weibull model has been selected as the best fit for this sub zone. The earthquake occurrence rate, corresponding to the selected model, is a smooth function of time and reveals two clusters within the time after an earthquake occurrence. The first cluster begins right after an earthquake occurrence, lasts about 80 years, and is explicitly time-dependent. The occurrence rate, regarding to this cluster, is considerably lower right after an earthquake occurrence, increases strongly during the following ten years and reaches its maximum about 0.024 events/year, then decreases over the next 70 years to its minimum about 0.0145 events/year. The second cluster begins 80 years after an earthquake occurrence and lasts until the next earthquake occurs. The earthquake occurrence rate, corresponding to this cluster, increases extremely slowly, such as it can be considered as an almost constant rate about 0.015 events/year. The results are applied to calculate the time-dependent PSHA in the northern part of the DSFZ and neighbouring areas.
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Mesures de la luminosité absolue à l'expérience LHCb

Hopchev, Plamen 25 November 2011 (has links) (PDF)
Les mesures de la luminosité intégrée pour les expériences auprés de collisionneur ont un intérêt majeur. Ces mesures participent à la détermination des sections efficaces de production des processus étudiés, elles quantifient également les performances de l'accélérateur et des expériences. Deux méthodes ont été utilisées par l'expérience LHCb pour déterminer la mesure de la luminosité absolue enregistrée durant la campagne 2010 de prise de données des collisions proton-proton à une énergie de 7 TeV dans le centre de masse: outre la méthode classique applelée "Van der Meer scan" une nouvelle technique est développée permettant une détermination directe des paramètres de chaque faisceau en localisant les interactions faisceau-faisceau et les interactions faisceau-gaz résiduel. Cette méthode n'est possible que grace à la résolution du détecteur de vertex de LHCb et sa proximité avec la zone des faisceaux de protons et les paramètres tels la position, les angles et les largeurs des faisceaux peuvent être mesurés. Les deux methodes sont décrites et leurs résultats discutés. De plus les techniques utilisées pour étendre les mesures de luminosité absolue à l'ensemble de la prise de données 2010 sont décrites.

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