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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.
31

Caractérisation fonctionnelle des protéines des appendices du corps basal et de la zone de transition / Functional caracterisation of basal body appendages and transition zone proteins of cilia

Augière, Céline 29 September 2017 (has links)
Les cils et les flagelles sont des organites conservés chez les eucaryotes où ils jouent des rôles essentiels et variés comme la motilité et la signalisation cellulaire. La zone de transition est une structure complexe, localisée à la base des cils, indispensable à l'assemblage du cil et pour la sélection des constituants ciliaires. Chez l'Homme, de nombreuses pathologies appelées ciliopathies sont associées à des défauts d'assemblage ou de fonctionnement des cils. Les plus sévères sont liées à des défauts de protéines de la zone de transition. La zone de transition comprend les fibres de transition qui font le lien entre le centriole et la membrane plasmique, puis les liens Y avec une composition protéique complexe organisé en 3 complexes, MKS, NPHP et CEP290 interagissant étroitement entre eux. D'autres protéines, dont CBY conservée des mammifères à la drosophile, s'ajoutent à ces modules mais leur interconnections ne sont pas connues.Au cours de ma thèse, j'ai caractérisé fonctionnellement les orthologues des protéines des fibres de transition et analysé la fonction de nouvelles protéines de la zone de transition en utilisant le modèle de la drosophile. J'ai également caractérisé une protéine impliquée dans la spermatogenèse qui est essentielle pour l'individualisation des spermatides et la fertilité des males.En conclusion, ce travail apporte de nouvelles connaissances sur l'assemblage de la zone de transition et sur le rôle de CBY dans les mécanismes qui contrôlent la ciliogenèse. De plus l'étude de Salto amène à une meilleure compréhension de la spermatogenèse chez la drosophile / Cilia and flagella are highly conserved organelles among eukaryotes species. They are composed of a microtubular cytoskeleton and play essential functions during development and in numerous physiological processes. As a result, in humans, cilia dysfunction leads to a wide range of pathologies, called ciliopathies
32

Métabolites de Pseudotsuga menziesii : approche métabolomique et rôle dans la résistance / Metabolites of Pseudotsuga menziesii : metabolomic approach and role in resistance

Mbakidi-Ngouaby, Henri 28 April 2017 (has links)
Pour l’identification et l’accès aux métabolites secondaires du bois de Douglas, les optimisations des conditions d’extractions ont été réalisées dans différents solvants. L’identification de composés par LC-MS/MS a été privilégiée. L’analyse en LC-ESI-MS/MS des extraits de bois issus des trois zones a été effectuée afin d’identifier les différents groupesde métabolites présents dans chaque zone. Une cinquantaine de métabolites a été identifié. Les groupes de métabolites les plus représentatifs sont les polyphénols et les terpènes qui sont réputés avoir des propriétés antioxydantes, antifongiques à l’origine de la durabilité naturelle du bois. Dans un deuxième temps la quantification relative de métabolites d’intérêt a été réalisée à partir d’échantillon de bois prélevés aux 4 saisons de l’année. Les résultats ont montré que le duramen était la zone la plus riche en métabolites quelque soit la saison. Cependant, la quantité de chaque métabolite varie différemment en fonction des saisons. Pour une majorité de composés quantifiés, le printemps et l’été sont les saisons au cours desquelles le bois accumulait une grande quantité de métabolites. Ces résultats confirment que leduramen est la zone la plus riche en métabolites protecteurs. Ces informations peuvent être utiles pour la sélection des lignées les plus résistantes et l’amélioration de la durabilité naturelle du bois. / For the identification and access to secondary metabolites of Douglas-fir, the optimization of the extraction conditions was carried out in different solvents. The identification of compounds by LC-MS / MS was favored. LC-ESI-MS / MS analysis of thewood extracts from the three zones was carried out to identify the different groups of metabolites present in each zone. About fifty metabolites have been identified. The most representative groups of metabolites are polyphenols and terpenes, which are said to have antioxidant, antifungal properties that are at origin of the natural durability of wood. In a second step, the relative quantification of metabolites of interest was carried out using wood samples taken during the 4 seasons of the year. The results showed that duramen was the richest metabolite area in any season. However, the amount of each metabolite varies differently depending on the season. For a majority of quantified compounds, spring and summer are the seasons in which wood accumulates a large amount of metabolites. These results confirm that the duramen is the area richest in protective metabolites. This information can be useful for selecting the most resistant lines and improving the natural durability of wood.
33

Étude du gène chibby, acteur de la voie de signalisation Wnt chez les mammifères, qui est nécessaire à la maturation des centrioles en corps basaux chez Drosophila melanogaster / Study of the chibby gene, actor in the Wnt signaling pathway in mamals, and necessary for the maturation of centrioles into basal bodies in Drosophila melanogaster

Enjolras, Camille 20 October 2011 (has links)
Les cils et flagelles sont des organites cellulaires retrouvés des protozoaires aux mammifères. Une dérégulation de l’assemblage (ciliogenèse) ou de la fonction des cils, entraîne diverses maladies chez l’homme. Parmi les acteurs de la ciliogenèse, se trouvent les facteurs de transcription RFX. La recherche de gènes cibles de RFX chez la drosophile a permis d’identifier le gène Chibby (Cby), précédemment décrit comme un antagoniste de la voie de signalisation Wnt/wingless. Contrairement aux vertébrés, chez les invertébrés aucun lien n’est encore établi entre cil et voie wg. L’identification de cby comme cible de dRFX chez la drosophile suggère une fonction ciliaire de cby et permettrait l’établissement du lien cil/voie wg. CBY se localise à la zone de transition des cils des neurones sensoriels du système nerveux périphérique et aux centrioles des spermatides. Les drosophiles invalidées pour cby présentent un phénotype de non coordination, mais aucun phénotype de type wg. Ces mutants ont des défauts des cils sensoriels, ainsi que des défauts d’organisation des spermatides. De plus, chez les embryons, les protéines actrices du transport intra-flagellaire, NompB et CG11356, sont mal distribuées lorsque CBY est absente. Enfin, chez les mutants, la localisation de la protéine UNC est affectée dans les cellules germinales en fin de spermatogenèse. En conclusion, chez la drosophile, CBY est impliquée dans le tri protéique organisé à la base du cil de neurones sensoriels, de concert avec les autres protéines localisées à la zone de transition. Dans le testicule, CBY est nécessaire à la maturation des spermatides. En revanche, CBY n‟intervient pas dans la régulation de la voie wg / Cilia and flagella are organelles found from protozoa to mammals. Deregulation of the assembly (ciliogenesis) or function of cilia, causes various diseases in humans. Among those involved in ciliogenesis are the RFX transcription factors. The search for RFX target genes in Drosophila identified the Chibby (CBY) gene, previously described as an antagonist of the Wnt / wingless pathway. Unlike in vertebrates, in invertebrates is still no link established between cilia and the wg pathway. The identification of CBY as a target of dRFX in Drosophila suggests a ciliary function of CBY and would allow the establishment of the link cilia / wg pathway. CBY is localized at the transition zone of cilia of sensory neurons of the peripheral nervous system and at centrioles in spermatids. Drosophila invalidated for CBY present a phenotype of uncoordination, but no wg phenotype. These mutants have defects in sensory cilia and defects in organization of spermatids. In addition, in embryos, the distribution of proteins involved in intra-flagellar transport, NompB and CG11356, is affected when CBY is absent. Finally, in the mutants, the localization of the UNC protein is affected in germ cells at the end of spermatogenesis. In conclusion, in Drosophila, CBY is involved in the protein sorting organized at the base of cilia of sensory neurons, with the other proteins located at the transition zone. In the testes, CBY is necessary for the maturation of spermatids. However, CBY is not involved in the regulation of the wg pathway
34

Spatio-temporal History of Fluid-rock Interaction in the Hurricane Fault Zone

Koger, Jace 01 May 2017 (has links)
The Hurricane Fault is a 250-km long, west dipping, Basin and Range-bounding normal fault in SW Utah and NW Arizona that initiated in the mid-Miocene to Pliocene. It has been primarily active in the Quaternary, with slip rates of 0.2 – 0.6 mm/yr. There are multiple hot springs along its 250-km length and multiple late Tertiary-Quaternary basaltic centers broadly parallel the fault. Possible sources of hot spring fluids include deeply-circulated meteoric water that experienced water-rock exchange at high temperatures (>100 °C) and deep-seated crustal fluids. Aside from the source of modern hot spring fluids and heat, questions about the spatio-temporal history of fluid flow along the Hurricane Fault remain unaddressed. Abundant damage zone veins, cements, and host rock alteration are present, indicative of past fluid flow. Carbonate veining and cementation is a key feature of the Hurricane Fault zone, and is the primary feature exploited to characterize the thermochemical history of fault-related paleofluids. A combination of macroscopic and microscopic carbonate observations, chemical composition, and precipitation temperature of calcite veins was used to determine past water-rock diagenetic interaction and vein evolution in the Hurricane Fault zone. Calcite iv in concretions and veins from the damage zone of the fault shows a wide range of carbon and oxygen stable isotope ratios, with δ13CPDB from -4.5 to 3.8 ‰ and δ18OPDB from -17.7 to -1.1‰. Fluid inclusion microthermometry homogenization temperatures range from 45 to 160 °C, with fluid salinities of 0 to 15 wt% NaCl calculated from melting temperatures. Combining the two datasets, two main fluids that interacted with the fault zone are inferred: (1) basin brines with a δ 18OSMOW of 9.2 ‰ and (2) altered meteoric fluids with a δ 18OSMOW of -11.9 to -8.3 ‰. Calculated dissolved CO2 δ 13CPDB (-8.5 to -1.3 ‰) indicates mixed marine carbonate and organic or magmatic sources. Fault zone diagenesis was caused by meteoric water infiltration and interaction with carbonate-rich rocks, mixed with upwelling basin brines. Fluid-rock interaction is concentrated in the damage zone, where fracture-related permeability was utilized for fluid flow. A distinct mineralization event punctuated this history, associated with basin brines that were chemically influenced by nearby basaltic magmatism. This implies a hydrologic connection between the fault and regional magmatism.
35

Numerical modelling of high-speed railway transition zone

Norberg, Karl January 2022 (has links)
Transition zones are changes in the track structure, detected by an abrupt deviationin track stiffness and/or differential settlements. One inevitable transition zone is thebridge approach. This study has investigated in this transition zone, adapted for highspeed,ballastless track. The aim was to observe the general behaviour of the transitionzone including its critical components, and to compare different measures, transitionconstructions, to manage with the eventual problems. A base model, called Nullmodel,was developed using the 3D finite element method to evaluate the behaviour of thetransition zone. Based on the Nullmodel, six comparative models have been created,including different types of transition constructions within the substructure. New forthis study is that it investigates the overall behaviour of the transition zone, and alsothe substitution of subballast in combination with approach blocks.For the general behaviour of the transition zone, the results have shown that theballastless track does not behave as a traditional ballasted track. Furthermore,the direction of travel affects the magnitude of different dynamical parameters.Comparing different transition constructions, replacing the subballast with ahydraulically bonded layer in combination with an approach block with cementbounded granular material is found to be the best alternative. Finally, the invertedapproach block is found to be an equally good, or better, mitigative measure incomparison with the regular approach block.
36

Mise en place et chimie des magmas dans le manteau supérieur de l'ophiolite d'Oman / Emplacement and geochemistry of magmas in the upper mantle section of the Oman ophiolite

Nicolle, Marie 21 February 2014 (has links)
L'ophiolite d'Oman permet d'observer les roches mantelliques inaccessibles aux dorsales. Avec cinq diapirs à l'axe (dont Maqsad) et un diapir hors-axe (Mansah), elle permet d'étudier les processus magmatiques en jeu dans les diapirs au niveau de la Zone de Transition au Moho, qui est différente entre les deux types de diapirs avec hors-axe des pyroxénites dans la dunite à la place de gabbros lités à l'axe. Le diapir de Mansah est entouré d'intrusions gabbroïques dans le manteau et la croûte. Les roches hors-axe ont des valeurs d'εNd plus faibles que celles à l'axe qui ont des compositions similaires aux MORB, suggérant une source des liquides plus riche en veines de pyroxénite hors-axe. Les εNd montrent aussi que les pyroxénites et les intrusions gabbroïques sont une suite magmatique. L'abondance de clinopyroxenes hors-axe provient de la réaction entre des liquides provenant de la fusion de veines de pyroxénites avec la harzburgite appauvrie de la lithosphère, ce qui donne à ces clinopyroxènes des compositions appauvries en éléments traces. La présence d'eau provenant de la lithosphère hydratée favorise la cristallisation de ces clinopyroxènes à la place du plagioclase qui doit normalement apparaître à cette profondeur dans la MTZ, ce qui est le cas à l'axe. Le diapir hors-axe pourrait fournir une analogie aux seamounts que l'on trouve actuellement à proximité des dorsales rapides et faire la lumière sur les interactions entre la lithosphère appauvrie et le matériel ascendant hors-axe, ainsi que sur les structures internes de ces seamounts. Ce travail offre des évidences probantes pour l'existence de veines de pyroxénites dans le manteau asthénosphérique sous les dorsales / The Oman ophiolite offers the possibility to study mantle rocks which are inaccessible at mid-ocean ridges. The presence of five on-axis diapirs and an off-axis diapir allows comparison of magmatic processes occurring in these different settings. The Moho Transition Zone is dominated by dunite in both cases, but off-axis includes massive pyroxenites instead of layered gabbro. The off-axis diapir is surrounded by gabbroic intrusions in the crust and mantle, which are not found elsewhere in the ophiolite. While the on-axis samples have εNd values similar to those of MORB, all of the off-axis rocks have less radiogenic Nd suggesting a larger contribution from melting of pyroxenite veins in the off-axis source. The abundance of clinopyroxene in the off-axis MTZ results from the reaction between the pyroxenite-derived melts and the depleted harzburgite of the lithosphere, which explains the highly depleted incompatible trace element compositions of the clinopyroxenes. The presence of water from the hydrated lithosphere favors the crystallization of clinopyroxene instead of plagioclase, which should normally appear at this depth in the MTZ, as is the case on-axis. The gabbroic intrusions in the mantle and crust surrounding the off-axis diapir crystallized from the residual magma produced by the interaction between the pyroxenite-derived melts and the harzburgite. The off-axis diapir could be viewed as an analog to seamounts currently found near fast-spreading ridges, and could provide information on their internal structure. More generally, this study provides compelling evidence for the existence of pyroxenite veins in the asthenospheric mantle beneath mid-ocean ridges
37

Análise da interface entre argamassas de concreto com adição de fino basáltico e cinza da casca de arroz por meio de nanoindentação

Wilbert, Daniel Gustavo Brusius 22 July 2015 (has links)
Submitted by Silvana Teresinha Dornelles Studzinski (sstudzinski) on 2015-10-28T11:36:30Z No. of bitstreams: 1 Daniel Gustavo Brusius Wilbert_.pdf: 4731645 bytes, checksum: 08c801a9545a481516dfe01632256d9c (MD5) / Made available in DSpace on 2015-10-28T11:36:30Z (GMT). No. of bitstreams: 1 Daniel Gustavo Brusius Wilbert_.pdf: 4731645 bytes, checksum: 08c801a9545a481516dfe01632256d9c (MD5) Previous issue date: 2015-07-22 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / FAPERGS - Fundação de Amparo à Pesquisa do Estado do Rio Grande do Sul / O setor da construção civil é responsável por um grande impacto ambiental, destacando-se dois principais fatores, a quantidade de matéria-prima consumida e de resíduos gerados. Estes resíduos, em grande parte apresentam um grande potencial de reciclagem. Dentre estes resíduos, os de concreto apresentam um excelente potencial de utilização. Inúmeras pesquisas já comprovaram a viabilidade de utilização do Agregado Reciclado de Concreto (ARC). Porém, a menor qualidade do ARC em comparação aos agregados naturais, resultada em queda no desempenho destes concretos, principalmente nas propriedades de durabilidade. Como consequência ocorre um enfraquecimento da zona de transição entre a argamassa velha e a nova. Em função desta queda de desempenho ao se utilizar ARC, a presente pesquisa teve por objetivo a análise desta zona de transição, através do estudo da interface entre duas argamassas de concreto por meio da técnica de nanoindentação. Para esta análise foram moldados agregados reciclados de concretos modificados, todos no traço referência (sem adição), e posteriormente aplicada uma nova camada de argamassas com diferentes traços. Os traços variaram entre dois tipos de adição (Finos Basálticos – FB e Cinza da Casca de Arroz – CCA), em diferentes teores de adição ao cimento, 0, 5, 10 e 15% para os finos e 0, 5 7,5 e 10% para a CCA. Após cura de 63 dias, as amostras foram preparadas para a realização dos ensaios. Para a análise das medidas de nanoindentação na interface, foram propostos três métodos de análise. As propriedades macroestruturais foram avaliadas aos 28 dias, como módulo de elasticidade dinâmico, resistência à compressão, resistência à tração por compressão diametral e absorção de água por capilaridade. Os resultados demonstraram a melhora das propriedades macroestruturais das argamassas com 15% de FB e CCA em relação à referência. Foram identificadas alterações na região de interface entre as argamassas no traço com 15% de finos de basalto e em todos os traços com CCA, que apresentaram os melhores resultados. A comparação entre a região mais próxima à zona de transição resultou, para todos os traços, em valores semelhantes aos obtidos em regiões de pastas mais distantes à zona de transição, demonstrando que o uso de uma argamassa antiga na condição seca (simulando um agregado reciclado seco) melhorou as condições da zona de transição com a argamassa nova. / Construction is responsible for a large environmental impact, highlighting two main factors: consume of raw materials and generation of waste materials. By other hand, construction and demolition waste has a good potential of recycling. Many studies have demonstrated the viability of using recycled concrete coarse aggregate (RCA) in new concrete. However, due to the RCA’s properties, most results point to a lower durability of the concrete. It is also consensus that the main reasons for the lower quality of the new concrete are the mortar layer adhered to the natural aggregate and the weakening in the new Interfacial Transition Zone (ITZ) between the old and the new mortar. This study analyze the new interfacial transition zone in these concretes through nanoindentation. There were produced recycled concrete aggregates without addition of filler, and over these aggregates there were produced a new mortar layer with different mix compositions. There were used basaltic filler and rice husk ash-RHA in different levels of addition: 0, 5, 10 and 15% for the filler, and 0, 5, 7,5 and 10% for the ash. Their interfaces were evaluated using different methodologies. Modulus of elasticity, compressive strength, tensile strength and capillarity were determined. The use of fines improved the mortar properties in relation to the reference, especially those with 15% filler and the samples with RHA. The region near to the ITZ shows similar elastic moduli values to those obtained in the paste, in all mortars, proving that using dry recycled aggregates the new mortar loose water to the aggregates and increase their mechanical properties.
38

Amplituden der Kernphasen im Bereich der Kaustik B und Untersuchung der Struktur der Übergangszone zum inneren Erdkern mit spektralen Amplituden der diffraktierten Phase PKP(BC)

Wolf, Michael D. C. January 2002 (has links)
Das Ziel dieser Arbeit ist es, die Strukturen im äußeren Erdkern zu untersuchen und Rückschlüsse auf die sich daraus ergebenden Konsequenzen für geodynamische Modellvorstellungen zu ziehen. Die Untersuchung der Kernphasenkaustik B mit Hilfe einer kumulierten Amplituden-Entfernungskurve ist Gegenstand des ersten Teils. Dazu werden die absoluten Amplituden der PKP-Phasen im Entfernungsbereich von 142 &#176; bis 147 &#176; bestimmt und mit den Amplituden synthetischer Seismogramme verglichen. Als Datenmaterial dienen die Breitbandregistrierungen des Deutschen Seismologischen Re-gionalnetzes (GRSN 1 ) und des Arrays Gräfenberg (GRF). Die verwendeten Wellen-formen werden im WWSSN-SP-Frequenzbereich gefiltert. Als Datenbasis dienen vier Tiefherdbeben der Subduktionszone der Neuen Hebriden (Vanuatu Island) und vier Nuklearexplosionen, die auf dem Mururoa und Fangataufa Atoll im Südpazifik stattgefunden haben. Beide Regionen befinden sich vom Regionalnetz aus gesehen in einer Epizentraldistanz von ungefähr 145 &#176;. Die Verwendung eines homogen instrumentierten Netzes von Detektoren und die Anwendung von Stations- und Magnitudenkorrekturen verringern den Hauptteil der Streuung bei den Amplitudenwerten. Dies gilt auch im Vergleich zu Untersuchungen von langperiodischen Amplituden im Bereich der Kernphasenkaustik (Häge, 1981). Ein weiterer Grund für die geringe Streuung ist die ausschließliche Verwendung von Ereignissen mit kurzer impulsiver Herdzeitfunktion. Erst die geringe Streuung der Amplitudenwerte ermöglicht eine Interpretation der Daten. Die theoretischen Amplitudenkurven der untersuchten Erdmodelle zeigen im Bereich der Kaustik B einen gleichartigen Kurvenverlauf. Bei allen Berechnungen wird ein einheitliches Modell für die Güte der P- und S-Wellen verwendet, das sich aus den Q-Werten der Modelle CIT112 und PREM 2 zusammensetzt. Die mit diesem Q-Modell berechneten Amplituden liegen in geringem Maße oberhalb der gemessenen Amplituden. Dies braucht nicht berücksichtigt zu werden, da die kumulierte Amplituden-Entfernungskurve anhand der Lage des Maximums auf der Entfernungsachse ausgewertet wird. Folglich wird darauf verzichtet, ein alternatives Q-Modell zu entwickeln.<br /> Hinsichtlich der Lage des Kaustikmaximums lassen sich die untersuchten Erdmodelle in zwei Kategorien einteilen. Eine Gruppe besteht aus den Modellen IASP91 und 1066B, deren Maxima bei 144.6 &#176; und 144.7 &#176; liegen. Zur zweiten Gruppe von Modellen zählen AK135, PREM und SP6 mit den Maxima bei 145.1 &#176; und 145.2 &#176; (SP6). Die gemessene Amplitudenkurve hat ihr Maximum bei 145 &#176;. Alle Entfernungsangaben beziehen sich auf eine Herdtiefe von 200 km. Die Kaustikentfernung für einen Oberflächenherd ist jeweils um 0.454 &#176; größer als die angegeben Werte. Damit liegen die Maxima der Modelle AK135 und PREM nur 0.1 &#176; neben dem der gemessenen kumulierten Amplitudenkurve. Daher wird auf die Erstellung eines eigenen Modells verzichtet, da dieses eine unwesentlich verbesserte Amplitudenkurve aufweisen würde. Das Ergebnis der Untersuchung ist die Erstellung einer gemessenen kumulierten Amplituden-Entfernungskurve für die Kaustik B. Die Kurve legt die Position der Kaustik B für kurzperiodische Daten auf &#177; 0.15 &#176; fest und bestimmt damit, welche Erdmodelle für die Beschreibung der Amplituden im Entfernungsbereich der Kaustik B besonders geeignet sind. Die Erdmodelle AK135 und PREM, ergänzt durch ein einheitliches Q-Modell, geben den Verlauf der Amplituden am besten wieder. Da die Amplitudenkurven beider Modelle nahe beieinander liegen, sind sie als gleichwertig zu bezeichnen.<br /> Im zweiten Teil der Arbeit wird die Struktur der Übergangszone in den inneren Erdkern anhand des spektralen Abklingens der Phase PKP(BC)diff am Punkt C der Laufzeitkurve untersucht. Der physikalische Prozeß der Beugung ist für die starke Abnahme der Amplituden dieser Phase verantwortlich. Die Diffraktion beeinflußt das Abklingverhalten verschiedener Frequenzanteile des seismischen Signals auf unterschiedliche Weise. Eine Deutung des Verhaltens erfordert die Berechnung von Abklingspektren. Dabei wird die Abschwächung des PKP(BC)diff Signals für acht Frequenzen zwischen 6.4 s und 1.25 Hz ermittelt und als Spektrum dargestellt. Die Form des Abklingspektrums ist charakteristisch für die Beschaffenheit der Geschwindigkeitsstruktur direkt oberhalb der Grenze zum inneren Erdkern (GIK). Die Beben, deren Kernphasen im Regionalnetz als diffraktierte Kernphasen BCdiff registriert werden, liegen in einem Entfernungsbereich jenseits von 150 &#176;. In dieser Distanz befinden sich die Erdbebenherde der Tonga-Fidschi-Subduktionszone, deren Breitbandaufzeichnungen verwendet werden. Die Auswertung unkorrigierter Wellenformen ergibt Abklingspektren, die mit plausiblen Erdmodellen nicht in Einklang zu bringen sind. Aus diesem Grund werden die Daten einer spektralen Stationskorrektur unterzogen, die eigens zu diesem Zweck ermittelt wird. Am Beginn der Auswertung steht eine Prüfung bekannter Erdmodelle mit unterschiedlichen Geschwindigkeitsstrukturen oberhalb der GIK. Zu den untersuchten Modellen zählen PREM, IASP91, AK135Q, PREM2, SP6, OICM2 und eine Variante des PREM. Die Untersuchung ergibt, daß Modelle, die einen verringerten Gradienten oberhalb der GIK aufweisen, eine bessere Übereinstimmung mit den gemessenen Daten zeigen als Modelle ohne diese Übergangszone. Zur Verifikation dieser These wird ein Erdmodell, das keinen verringerten Gradienten oberhalb der GIK besitzt (PREM), durch eine Reihe unterschiedlicher Geschwindigkeitsverläufe in diesem Bereich ergänzt und deren synthetische Seismogramme berechnet. Das Resultat der Untersuchung sind zwei Varianten des PREM, deren Frequenzanalyse eine gute Übereinstimmung mit den Daten zeigt. Das Abklingspektrum des Erdmodells PD47, das in einer 380 km mächtigen Schicht einen negativen Gradienten besitzt, zeigt eine große Ähnlichkeit mit den gemessenen Spektren. Dennoch kann es nicht als realistisches Modell angesehen werden, da der Punkt C in einer zu großen Entfernung liegt. Darüber hinaus müßte die zu kurze Differenzlaufzeit zwischen PKP(AB) und PKP(DF) beziehungsweise PKIKP durch eine größere Änderung der Geschwindigkeitsstruktur im inneren Kern kompensiert werden. Es wird deshalb das Modell PD27a favorisiert, das diese Nachteile nicht aufweist. PD27a besitzt eine Schicht konstanter Geschwindigkeit oberhalb der GIK mit einer Mächtigkeit von 150 km. Die Art des Geschwindigkeitsverlaufs steht im Einklang mit der geodynamischen Modellvorstellung, nach der eine Anreicherung leichter Elemente oberhalb der GIK vorliegt, die als Ursache für die Konvektion im äußeren Erdkern anzusehen ist. / In this thesis the structure of the outer core is investigated with PKP core phases. The knowledge of the physical properties of the earth&prime;s deep interior in this region is important for the understanding of geodynamical processes like the convective flow in the liquid outer core and the differential rotation of the earth&prime;s inner core.<br /> The first part of this thesis describes the investigation of the PKP caustic point B near 145 &#176;. For this purpose a cumulative amplitude distance curve is determined and compared with theoretical amplitude distance curves of different standard earth models. The data are broadband seismograms of the German Regional Seismic Network (GRSN) and the Gräfenberg Array (GRF). In order to measure the absolute amplitudes of the PKP phases, a WWSSN-SP filter is applied to the seismograms. The source regions are located in the South Pacific near Vanuatu Island (4 earthquakes) and on the French atolls Mururoa and Fangataufa (4 explosions). The advantage of a standardized network of seismic stations and the usage of station and magnitude corrections is a reduction of the scatter of the amplitude data. There is even less scatter than in studies with long period amplitude data (Häge, 1981). Another reason for the reduced scattering is the use of events with an impulsive source time function. Only the low scattering of the amplitude values makes it possible to interpret the data. More scattering of the data would have prevented an interpretation. The theoretical amplitude curves are similar in the caustic B distance range. The Q depth distribution for P and S waves used for calculating the synthetic seismograms is a combination of the values of the models CIT112 and PREM. The amplitudes determined with the help of this kind of model are slightly higher than the actually measured amplitudes. However, this needs not be taken into account because the interpretation is based on the position of the caustic peak. Therefore I rejected the computation of an improved Q model.<br /> Regarding the position of the caustic point there are two categories of earth models. The first group consists of the models IASP91 and 1066B with their maxima at 144.6 &#176; and 144.7 &#176; respectively. AK135, PREM and SP6 belong to a second group of models with caustic peaks at 145.1 &#176; and 145.2 &#176; (SP6). The measured curve has its maximum at 145 &#176;. All distances refer to a source depth of 200 km. For a surface focus the increase in distance is 0.454 &#176;. Therefore the peaks of the models AK135 and PREM are only 0.1 &#176; beside the maximum of the measured amplitude curve. The main result of this investigation is the amplitude distance curve in the vicinity of the cusp B. The curve determines the position of this point with an accuracy of &#177; 0.15 &#176; and points to earth models which would be good for modeling the amplitudes in the distance range of the PKP caustic B. The synthetic seismograms calculated for AK135 and PREM together with a standardized Q model fit the measured amplitude curve equally well.<br /> In the second part of this study the structure of the transition zone to the earth&prime;s inner core is investigated by using the spectral decay of the diffracted wave PKP(BC)diff at point C of the travel time curve. The physical process of diffraction is responsible for the strong reduction in amplitude of this wave. The influence of the diffraction on the seismic signal strongly depends on frequency. The interpretation of this phenomenon requires a calculation of decay spectra. In practice the attenuation of the PKP(BC)diff signal for eight frequencies between 6.4 s and 1.25 Hz are measured and visualized as a decay spectrum. The shape of a spectrum is characteristic of the velocity gradient above the inner core boundary (ICB). Those earthquakes whose core phases are recorded as diffracted core phases BCdiff lie beyond 150 &#176;. In this distance range there are the epicenters of the Tonga-Fiji slab. The broadband waveform data of the earthquakes in this region is used in this study. Decay spectra of waveform data which are not corrected for station site effects are incompatible with standard earth models. Therefore a spectral station correction is applied, which was especially determined for this purpose. The investigation starts with a review of a number of well-known earth models like PREM, IASP91, AK135Q, PREM2, SP6, OICM2 and a version of PREM. All these models have different velocity structures at the ICB. It is shown that models with a reduced velocity gradient above the ICB agree with the data rather than models without such a transition zone. For verification purposes a model without such a reduced gradient (PREM) is completed with different kinds of gradient zones to calculate synthetic seismograms. Two variants of the PREM correspond with the measured decay constants. The decay constants of model PD47 are very close to the measured ones. This model has a 380 km thick negative gradient above the ICB. Nevertheless it is not a realistic model because point C lies in a unrealistic great distance. As a result of the low velocity zone above the inner core there is a differential travel time between the PKP(AB) and the PKP(DF) phase (also PKIKP) which is too short. This would have to be compensated by a correction of the velocities in the inner core. Thus PD27a is the most suitable model which does not have the above mentioned disadvantages. PD27a has a 150 km thick layer of constant velocity above the ICB. This kind of velocity model is compatible with geodynamical theories according to which an enrichment of light elements above the ICB is present and powers the convection in the outer earth core by its buoyancy.
39

Morbidity and Discomfort of Ten-Core Biopsy of the Prostate Evaluated by Questionnaire

Manseck, Andreas, Guhr, Karsten, Fröhner, Michael, Hakenberg, Oliver W., Wirth, Manfred P. 17 February 2014 (has links) (PDF)
Transition zone biopsies have been found to increase the detection rates of cancer of the prostate in patients with negative digital rectal examination. There are however no data available whether the higher biopsy rate is associated with greater morbidity. The present study was therefore designed to evaluate the complication rate of extended sextant biopsy. In this prospective study, 162 consecutive patients who presented for prostatic evaluation were included. After starting prophylactic antibiotic treatment 48 h prior to the procedure, transrectal ultrasound-guided core biopsies were obtained from each lobe: three each from the peripheral zone (apex, mid-zone and base) and two from the transition zone of each prostatic lobe. In all patients a questionnaire was obtained 10–12 days after the procedure. Major complications occurred in 3 patients. In 2 of the 3 cases major macroscopic hematuria was treated by an indwelling catheter for 1 or 2 days and 1 patient developed fever >38.5°C for 1 day. Minor macroscopic hematuria was present in 68.5% of the patients. In 17.9% of these cases, the hematuria lasted for more than 3 days. Hematospermia was observed in 19.8% and minor rectal bleeding occurred in 4.9%. Ten-core biopsies did not lead to an increase in adverse effects or complications when compared to the results of sextant biopsies reported in the literature. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.
40

Time dependent material properties of shotcrete for hard rock tunnelling

Bryne, Lars Elof January 2014 (has links)
In this thesis different mechanical properties for shotcrete (sprayed concrete) such as compression strength, bond strength, bending tensile strength, elastic modulus, free and restrained shrinkage as a function of its age was investigated. One of the main issues was to investigate the difference between ordinary cast concrete and shotcrete. Reliable material data for young and hardening shotcrete is scarce which in the past have made such comparisons difficult. Also, less accurate data representative for cast concrete has often been used in numerical modelling and design analyses. The focus of the project has particularly been on the properties bond strength and restrained shrinkage for which two new testing methods has been developed and evaluated. Microstructural studies have also been performed as a complement to the bond strength testing. The bond to rock is one of the most important properties for shotcrete used as rock reinforcement. During the very first time after spraying the physical properties and the bond to the rock depend on the set accelerator and the micro structure that is formed. The investigation of early age bond strength of shotcrete is of great importance both from a production perspective and a safety perspective. The newly developed method was tested and evaluated and proved that it can be used for bond strength testing already from a couple of hours after shotcreting. The bond, or adhesion, depends on several factors such as texture of the rock, the type of accelerator, application technique, etc. In this work the development of the microstructure in the interfacial transition zone (ITZ) and strength of the bond was investigated. The results show that the bond strength is related to the hydration process, i.e. the strength gain of the shotcrete. The early development of the ITZ was here studied using a scanning electron microscope (SEM) making it possible to observe changes over time, before and after proper cement hydration. Restrained shrinkage cracking of shotcrete, especially in the case of shotcrete sprayed on soft drains that are parts of a tunnel lining not continuously bonded to the rock, can be detrimental for the sustainability of an infrastructure tunnel system. Maintenance and repair costs can be high over time. It is shown that the developed test method realistically captures the behaviour of shotcrete drains on hard rock in situ. The method can be used in the evaluation of different technical solutions for avoiding or minimizing shrinkage cracks in shotcreted soft drains. It can also be used to assess the performance of shotcrete fully bonded to a rock surface, with respect to the ability to prevent cracking or to distribute possible shrinkage damage into several fine cracks instead of one wide. / <p>QC 20140526</p>

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