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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.
261

U/Pb Zircon Ages of Plutons from the Central Appalachians and GIS-Based Assessment of Plutons with Comments on Their Regional Tectonic Significance

Wilson, John Robert 08 October 2001 (has links)
The rocks of the Appalachian orogen are world-class examples of collisional and extensional tectonics, where multiple episodes of mountain building and rifting from the pre-Cambrian to the present are preserved in the geologic record. These orogenic events produced plutonic rocks, which can be used as probes of the thermal state of the source region. SIMS (secondary ion mass spectrometry) U/Pb ages of zircons were obtained for ten plutons (Leatherwood, Rich Acres, Melrose, Buckingham, Diana Mills, Columbia, Poore Creek, Green Springs, Lahore and Ellisville) within Virginia. These plutons are distinct chemically, isotopically, and show an age distribution where felsic rocks are approximately 440 Ma, and Mafic rocks are approximately 430 Ma. Initial strontium isotopic ratios and bulk geochemical analyses were also performed. These analyses show the bimodal nature of magmatism within this region. In order to facilitate management of geologic data, including radiometric ages, strontium isotope initial ratios and major element geochemistry, a GIS based approach has been developed. Geospatially references sample locations, and associated attribute data allow for analysis of the data, and an assessment of the accuracy of field locations of plutons at both regional and local scales. The GIS based assessment of plutons also allows for the incorporation of other multidisciplinary databases to enhance analysis of regional and local geologic processes. Extending such coverage to the central Appalachians (distribution of lithotectonic belts, plutons, and their ages and compositions) will enable a rapid assessment of tectonic models. / Master of Science
262

Investigation of the monazite chemical dating technique

Loehn, Clayton William 06 June 2011 (has links)
In order to evaluate the electron microprobe (EMP) method for chemical dating of monazite, we chemically analyzed selected suites of monazite grains that were previously dated by standard U/Pb isotopic methods at three laboratories each equipped with a sensitive high resolution ion microprobe (SHRIMP). Representing diverse igneous and metamorphic lithologies, these grains yielded conventional isotopic ages ranging in age from Neoarchean to Devonian. Chemical dating was performed at Virginia Tech using a Cameca SX-50 EMP in which the analytical routines and settings were specifically optimized for monazite geochronology, including correction of analytical peaks for all major spectral interferences and correction of peak intensities for local background emission. Placement of cross-grain analytical traverses was based on backscattered electron (BSE) images together with wavelength-dispersive (WD) generated X-ray maps for Y, Th, U, and Ca, which revealed the internal compositional complexity of each grain. Shorter EMP traverses were selected adjacent to each SHRIMP pit in order to provide the best possible comparison of ages obtained by the two dating methods. Synthesis protocol for key elemental measurements (Y, Th, U, and Pb) was developed utilizing the 1Ï elemental errors associated with individual analyses, providing an objective approach for data synthesis. Analytical dates were either accepted or excluded based on analytical and spatial justifications. Isotopic dating techniques utilize three independent age calculations, provided the sample is old enough to have accumulated sufficient 207Pb (i.e., ≥~1000 Ma). Similarly, the chemical dating method can utilize two independent age calculations (i.e., Th/Pb and U/Pb) and a U-Th-Pbtotal centroid age in Th/Pb vs. U/Pb space, verified independently against the calculated Th* or U* CHIME ages. Across the entire 2,200 m.y. age range represented by the sample set, the chemical ages calculated from the EMP data chemical ages are internally consistent (within 2Ï error) with the previously measured SHRIMP isotopic ages, except in one case where bulk mixing of discrete age domains within an ablation pit led to an isotopically discordant apparent age. Overall, this study illustrates that EMP chemical dating (1) represents both an accurate and precise primary method for dating monazite from igneous and polymetamorphic terrains; (2) provides superior spatial resolution for obtaining meaningful ages from small and/or irregular domains of discrete age that may be irresolvable or misinterpreted by other dating techniques that sample larger volumes; and (3) illuminates the geological meaning of isotopically discordant monazite ages obtained using conventional methods with lower spatial resolution (e.g., SHRIMP). / Ph. D.
263

Neuromedin U can exert colon-specific, enteric nerve-mediated prokinetic activity, via a pathway involving NMU1 receptor activation.

Dass, N.B., Bassil, A.K., North-Laidler, V.J., Morrow, R., Aziz, E., Tuladhar, Bishwa R., Sanger, G.J. January 2007 (has links)
No / The neuromedin U (NMU) receptors, NMU1 and NMU2, are expressed in the gut but their functions are unclear. This study explores the role of NMU in gastrointestinal motility. Experimental approach: The effects of NMU were examined in the forestomach and colon isolated from NMU2R wild-type and NMU2R-/- (knockout) mice, looking for changes in muscle tension and in nerve-mediated responses evoked by electrical field stimulation (EFS), and in models of peristalsis in mouse colon and faecal pellet transit in guinea-pig colon. Key results: In the mouse forestomach, NMU (1 nM-10 ¿M) concentration-dependently induced muscle contraction, in the presence of tetrodotoxin and atropine, in preparations from both wild-type and NMU2R-/- mice (pEC50: 7.9, 7.6, Emax: 0.26, 0.20g tension, respectively, n=8 each concentration). The same concentrations of NMU had no consistent effects on the responses to EFS (n=8). In the mouse colon, NMU (0.1 nM-1 ¿M) had no significant effect on baseline muscle tension (n=8), but concentration-dependently potentiated EFS-evoked contractions in preparations from both wild-type and NMU2R-/- mice, pEC50: 8.1, 7.8, Emax: 24%, 21%, respectively, n=6-11. NMU (0.01 nM-0.1 ¿M, n=5-7) concentration-dependently decreased the interval between waves of peristalsis in the mouse colon (pEC50: 8.8) and increased the rate at which a faecal pellet moved along the guinea-pig colon. Conclusions and implications: These results demonstrate that NMU exerts colon-specific, nerve-mediated, prokinetic activity, via a pathway involving activation of NMU1 receptors. This suggests that this receptor may represent a molecular target for the treatment of intestinal motility disorders.
264

Ch3 U-Pb Zircon Results for Bedrock Samples LA-ICPMS

Wai Kehadeezbah Allen (14671736) 17 May 2024 (has links)
<p>U-Pb zircon results are presented with a U-Pb zircon Datatables for Bedrock Samples excel data sheet that have information for location (GPS and Geographic) and sample information. In addition, raw data formats of each individual sample is included that have additional information about laser settings per analysis.</p> <p><br></p> <p>Note the raw dataset for sample 062618WA-01 is included with two other analyses that are NOT bedrock samples. Use caution.</p> <p><br></p> <p>All analyses were conduction at the University of Arizona LaserChron Center ( <strong>NSF-EAR 1649254 </strong> )</p>
265

Ch3- U-Pb zircon data for Plutonic Clasts from Conglomerate

Wai Kehadeezbah Allen (14671736) 17 May 2024 (has links)
<p>U-Pb zircon datasets for Plutonic Clasts collected from conglomerate are presented first as a summary that includes sample name, GPS location, and datatables for each sample.</p> <p><br></p> <p>Additionally, raw datasets for each sample are included that includes detailed information on laser settings for each analyses</p> <p><br></p> <p>Note: Sample 062618WA-01 is included in one raw dataset as three igneous samples were analyzed on the same sample mount. This particular sample is a bedrock sample. Use caution</p> <p><br></p> <p>All analyses were completed at the University of Arizona Laserchron Center (NSF-EAR 1649254)</p>
266

Ch4- IODP Exp 341 U-Pb Detrital Zircon Results

Wai Kehadeezbah Allen (14671736) 17 May 2024 (has links)
<p>This dataset includes a summary excel file that details all the datatables for each detrital zircon sample and their location relative to each site and depth collected.</p> <p><br></p> <p>In addition to this summary, raw datasets for each individual analyses is included that have detailed information regarding the laser settings used for analyses.</p> <p><br></p> <p>All datasets were analyzed at the University of Arizona LaserChron Center (NSF-EAR 1649254)</p>
267

Unga kvinnors upplevelse av prestationsångest inom lagidrott

Wikblad, Frida, Andersson, Malin January 2024 (has links)
Prestationsångest är ett vanligt ämne inom idrott. Syftet med studien var att undersöka hur unga kvinnor inom lagidrott upplever prestationsångest. Semistrukturerade intervjuer genomfördes med 10 unga kvinnor mellan 18–25 år som spelade i samma handbollslag. Intervjuerna transkriberades och tematiserades där 6 teman identifierades: individernas upplevelse av prestationsångest, lagom prestationsångest ger bra prestation, lagkamraterna minskar prestationsångest, tränarna ökar prestationsångesten, prestationsångest ökar vid match, hög prestationsångest ger sämre spel. Studiens resultat visade att prestationsångest hos spelarna upplevdes på olika sätt både psykiskt och fysiskt, där mängden prestationsångest påverkade. Prestationsångesten påverkades olika av lagkamraterna och tränarna vilket främst upplevdes vid match. Utifrån tidigare forskning diskuterades hur mängden prestationsångest bidrog till idrottarens prestation där den omvända U-kurvan beskriver förhållandet mellan anspänning och prestation. Hur spelarna uppfattade lagkamraterna som minskande faktor till prestationsångest är något som diskuteras. Studien kan ge mer kunskap och en djupare förståelse för hur unga kvinnor upplever prestationsångest inom lagidrott.
268

How bright does the sun shine over Storvreta IK? : Mapping the energy use of a local Swedish sports club

Dahmén, Viktor, Holgersson, Martin, Larsson, Aron, Norman, Joel January 2016 (has links)
In 2011 Storvreta IK installed two solar collector systems in order to reduce the club’s electricity demand for domestic hot water. However, electricity use from 2012 to 2015 shows that the expected reduction in the electricity demand has not occurred. This project investigates the solar collector systems and the heat demand of Storvreta IK’s buildings in order to explain the “failure” in electricity savings. The results of the simulations show that the heat production of the solar collectors is lower than Storvreta IK’s expectations. This could be explained by that the domestic hot water is not used as much as Storvreta IK thought and the system is therefore over-dimensioned for their need. The rebound effect could be another reason to why the electricity saving is lower than expected.
269

Anti Roll Tanks in Pure Car and Truck Carriers

Windén, Björn January 2009 (has links)
<p>This is a master thesis conducted at KTH Centre for Naval Architecture in collaboration with Wallenius Marine AB.</p><p>Rolling motions is something that is undesired in all kinds of seafaring. In terms of propulsion resistance, comfort and route planning it would be desirable to reduce these motions. This thesis is an investigation on how different roll stabilising systems affect the performance of an 8000 unit PCTC vessel, special emphasis is put on investigating the performance of anti roll tanks. The ship in question has a recorded incidence of parametric rolling and the ability of the tanks to countervail this phenomenon is also investigated.</p><p>The tank and fin stabilising systems are relatively equal when it comes to roll damping performance related to changes in the required forward propulsion power. The tanks however, have a higher potential for improvements, addition of features such as heeling systems and parametric roll prevention systems.</p><p>The tank performance is also independent of the speed of the ship. The tanks are easier to retrofit and do not require the ship to be put in dry dock during installation. The conclusion of this thesis is that a combined anti roll and heeling system should be installed but that a further study has to be made on the performance of active rudder stabilisation.</p><p>It is shown that passive tanks are efficient at preventing parametric rolling in some sea states. A proposal is made for a further study on a control system that could achieve the same performance for all sea states.</p> / <p>HTML clipboard Detta är ett examensarbete utfört på KTH Marina System i samarbete med Wallenius Marine AB.</p><p>Rullningsrörelser är något som är oönskat i all form av sjöfart. Framsteg kan göras i både framdrivningsmotstånd, komfort och ruttplanering om dessa rörelser kunde minskas. Detta examensarbete består av en undersökning hur olika system för rulldämpning påverkar prestandan hos ett 8000 enheters PCTC-fartyg. Speciell vikt har lagts vid att undersöka prestandan hos antirulltankar. Det undersökta fartyget har en dokumenterad incident med parametrisk rullning och tankarnas förmåga att motverka detta fenomen undersöks.</p><p>Tank- och fenstabilisatorer är i princip likvärdiga vad det gäller dämpningsprestanda relaterat till erforderliga ändringar i framdrivningseffekten. Tankarna har dock en större potential för förbättring och tillägg av ytterligare inslag som krängningshämmare och system för motverkan av parametrisk rullning. Tankarnas prestanda är också oberoende av fartygets fart.</p><p>Tankarna är lättare att installera i efterhand och kräver inte att fartyget läggs i torrdocka under installationen. Slutsatsen av detta arbete är att en kombinerad antirull- och krängningshämmande tank bör installeras men att en vidare studie måste göras på prestandan hos aktiva roderstabiliseringssystem.</p><p>Det visas att passiva tankar kan motverka parametrisk rullning i vissa sjötillstånd. Ett förslag om en vidare studie på reglersystem som skulle kunna ge samma prestanda vid alla sjötillstånd ges.</p><p> </p>
270

The United States Supreme Court's Volitional Agendas, 1801-1993: Historical Claims versus Empirical Findings

Ogundele, Ayodeji O. 05 1900 (has links)
In this study, I examined the Supreme Court's agenda from 1801 to 1993 to determine the composition and dynamics of the issues that have dominated the business of the Court. Specifically, I set out to test empirically Robert G. McCloskey's (now standard) characterization of the Supreme Court's history, which sees it as dominated by nationalism/federalism issues before the Civil War, by economic issues just after the War through the 1930s, and by civil rights and liberties since the 1930s. The question that drove my investigation was "Is McCloskey's interpretation, which appears to be based on the great cases of Supreme Court history, an accurate description of the agenda represented in the Supreme Court's total body of reported decisions?" To test McCloskey's historical theses I employed concepts adapted from Richard Pacelle's (1991) important work on the agenda of post-Roosevelt Court and used the methods of classical historical analysis and of interrupted time-series analysis. Data for my research came from existing datasets and from my own collection (I coded the manifest content of thousands of Supreme Court's decisions from 1887 back to 1801). The most important finding from my analyses is that McCloskey not withstanding, the pre-Civil War Supreme Court's agenda was clearly dominated by economic issues of various sorts, not by nationalism/federalism as previously believed. Another key finding is that partisanship had a pronounced impact on the Court's attention to this category of issueseven in the periods when the Supreme Court had very little control of its docket. These results suggest that Supreme Court scholars should reassess or rethink their previous notion of the Court's pre-Civil War agendathe now well-established view that nation-state issues dominated the business of the Court in its formative yearsand the idea (often expressed implicitly) that the Court's mandatory jurisdiction suppressed attitudinal factors on the Court in the earlier eras.

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