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Showing result 1 - 5 of 430 swedish dissertations matching the above criteria.

  2. 1. Geochemical and sedimentary signatures of Phanerozoic events

    Author : Jane Wigforss-Lange; Berggrundsgeologi; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; geokemi; Sedimentology; Petrology; mineralogy; geochemistry; Petrologi; mineralogi; Carbon and oxygen isotopes; Jurassic-Cretaceous boundary; K-T boundary; Late Silurian; Events; Trace elements; Sedimentologi;

    Abstract : Geological and biological catastrophic events have occurred repeatedly in the Earth's history, leaving traces in the global stratigraphical record in the form of sedimentary features, geochemical anomalies and biotic turnovers. This thesis focuses on the sedimentological and geochemical signatures of several key events in the Phanerozoic stratigraphical record, and aims to interpret the different signals and the causal mechanisms behind each of these events. READ MORE

  4. 2. Multiple Time Scales and Longitudinal Measurements in Event History Analysis

    Author : Danardono; Umeå universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Statistics; Cox regression; multiple events; proportiona hazards; random effects; survival analysis; time-dependent covariates; time origin; Statistik; Statistics; Statistik; Statistics; statistik;

    Abstract : A general time-to-event data analysis known as event history analysis is considered. The focus is on the analysis of time-to-event data using Cox's regression model when the time to the event may be measured from different origins giving several observable time scales and when longitudinal measurements are involved. READ MORE

  5. 3. Multiple Parton Interactions in Deep Inelastic ep-scattering at HERA

    Author : Sakar Osman; Partikel- och kärnfysik; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Jet Calibration; H1; Jets; Mini-jets; MPI; Low-x; Multiple; Dijets; Parton Dynamics; HERA; Fysicumarkivet A:2008:Osman;

    Abstract : The production of jets with low transverse momenta (mini-jets) in deep inelastic electron-proton scattering is studied. The analyses uses data taken with the H1 detector at HERA during the years 1999 to 2000. READ MORE

  6. 4. Environmental risk factors for multiple sclerosis

    Author : Jonatan Salzer; Peter Sundström; Kjell-Morten Myhr; Umeå universitet; []
    Keywords : MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Multiple sclerosis; risk factors in epidemiology; prospective; month of birth; vitamin D; vitamin A; C-reactive protein; hygiene hypothesis; smoking; cotinine; Epstein-Barr virus; Epidemiology; epidemiologi;

    Abstract : Background Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system. It usually strikes during young adulthood, and 2.5 million individuals are estimated to have the disease worldwide. READ MORE

  7. 5. Computational problems in evolution : Multiple alignment, genome rearrangements, and tree reconstruction

    Author : Isaac Elias; Jens Lagergren; Lior Pachter; KTH; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Distance Methods; Tree reconstruction; Sorting by Transpositions; multiple alignment; ancestral sequences; Computer science; Datavetenskap;

    Abstract : Reconstructing the evolutionary history of a set of species is a fundamental problem in biology. This thesis concerns computational problems that arise in different settings and stages of phylogenetic tree reconstruction, but also in other contexts. READ MORE