Search for dissertations about: "echo changes"

Showing result 1 - 5 of 29 swedish dissertations containing the words echo changes.

  2. 1. The aging brain and changes in cognitive performance : Findings from morphometry and quantitative susceptibility mapping of iron

    Author : Ninni Persson; Håkan Fischser; Kristine B. Walhovd; Stockholms universitet; []
    Keywords : SAMHÄLLSVETENSKAP; SOCIAL SCIENCES; brain aging; volumes; ndividual differences; QSM; cognitive aging; iron; episodic memory; fluid-; crystalized abilities; sex differences; gender differences; Psychology; psykologi;

    Abstract : Brain aging is a heterogeneous phenomenon, and this thesis illustrates how the course of aging can vary within individuals over time and between individuals as a function of age, sex, and genetic variability. We used two contrasts from magnetic resonance imaging (MRI), namely spin-lattice T1-weighted imaging, and quantitative susceptibility mapping (QSM) from gradient-echo images, to picture the aging brain, by means of morphometric measures and brain-iron concentrations. READ MORE

  4. 2. Diffusion MRI: Aspects of Reproducibility and Novel Segmented 2D and 3D Approaches for Higher Resolution and Geometric Fidelity

    Author : Jens Johansson; Göteborgs universitet; []
    Keywords : MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Diffusion-weighted imaging; 3D-DWI; Time-Dependent ADC; DWi; Diffusion Time; Multi-Shot DWI; Echo- Planar Imaging; Geometric Distortion;

    Abstract : Diffusion-weighted imaging (DWI) is a very useful tool for non-invasive imaging and clinical investigation of the human body. It provides data of the water diffusion process. READ MORE

  5. 3. The role of young-of-the-year fish in lake ecosystems

    Author : Pia Romare; Biologiska institutionen; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Hydrobiology; Rutilus rutilus; Perca fluviatilis; diet-dependent growth; density dependent growth; behavioural cascade; 0 fish behaviour; horizontal echo sounding; biomanipulation; trophic cascade; predation pressure; young-of-the-year fish; trophic interactions; marine biology; aquatic ecology; limnology; Marinbiologi; limnologi; akvatisk ekologi; Ecology; Ekologi;

    Abstract : Food chain theory is based on consumption; that is, presupposing that the only important interaction between organisms is that they actually meet in an unstructured environment and that one of them is consumed. Recently, studies, including biomanipulation projects, have indicated that trophic interactions are more complex than predicted by food chain theory. READ MORE

  6. 4. Hydrology and Bed Topography of the Greenland Ice Sheet : Last known surroundings

    Author : Katrin Lindbäck; Rickard Pettersson; Francisco Navarro; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; climate change; Greenland Ice Sheet; radio-echo sounding; digital elevation models; ice thickness; bed topography; spectral analysis; roughness; subglacial hydrology; water piracy; englacial features; drainage catchments; meltwater runoff; ice dynamics; klimatförändringar; Grönlands inlandsis; markbaserad radar; digitala höjdmodeller; istjocklek; bottentopografi; spektralanalys; subglacial hydrologi; englaciala strukturer; avrinningsområden; isdynamik;

    Abstract : The increased temperatures in the Arctic accelerate the loss of land based ice stored in glaciers. The Greenland Ice Sheet is the largest ice mass in the Northern Hemisphere and holds ~10% of all the freshwater on Earth, equivalent to ~7 metres of global sea level rise. READ MORE

  7. 5. Systemic Lupus Erythematosus, with focus on vascular wall changes, cardiac risk-factor awareness and cardiovascular events

    Author : Christine Bengtsson; Reumatologi och molekylär skelettbiologi; []
    Keywords : MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; microvascular reactivity; arteria stiffness; cardiac risk factors; Cardiovascular event; SLE;

    Abstract : Systemic Lupus Erythematosus is an autoimmune disease with a wide range of disease manifestations with respect to severity and magnitude of organ involvement. An increased risk of cardiovascular disease (CVD) compared with the general population causes both morbidity and mortality in SLE patients. READ MORE