Search for dissertations about: "perturbation effects"

Showing result 1 - 5 of 131 swedish dissertations containing the words perturbation effects.

  2. 1. Extinctions in Ecological Communities : direct and indirect effects of perturbation on biodiversity

    Author : Alva Curtsdotter; Bo Ebenman; Peter Münger; Elisa Thébault; Linköpings universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES;

    Abstract : In the dawning of what may become Earth’s 6th mass extinction the topic of this thesis, understanding extinction processes and what determines the magnitude of species loss, has become only too relevant. The number of known extinctions (~850) during the last centuries translates to extinction rates elevated above the background rate, matching those of previous mass extinction events. READ MORE

  4. 2. Essays on Empirical Macroeconomics

    Author : Dario Caldara; John Hassler; Giancarlo Corsetti; Stockholms universitet; []
    Keywords : SAMHÄLLSVETENSKAP; SOCIAL SCIENCES; Fiscal Policy; Identification; Vector Autoregression; Recursive Preferences; Perturbation; DSGE Models; Business Cycle Accounting; Economics; Nationalekonomi; Economics; nationalekonomi;

    Abstract : This thesis consists of four essays in empirical macroeconomics. What Are the Effects of Fiscal Policy Shocks? A VAR-Based Comparative Analysis The literature using structural vector autoregressions (SVARs) to assess the effects of fiscal policy shocks strongly disagrees on the qualitative and quantitative response of key macroeconomic variables. READ MORE

  5. 3. Diversity and Ecosystem Functioning : Redundancy and Resilience in Freshwater Bacterial Communities

    Author : Hannes Peter; Lars J. Tranvik; Eva S. Lindström; Silke Langenheder; Nelson G. Hairston; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; biodiversity; ecosystem functioning; bacteria; fresh water; biofilms; multifunctionality; ecological networks; perturbation; fragility; Biologi med inriktning mot limnologi; Biology with specialization in Limnology;

    Abstract : Bacteria are immensely diverse and hold key-positions in essentially all biogeochemical cycles. In freshwater ecosystems, bacteria degrade and mineralize organic compounds, linking the pool of dissolved organic matter to higher trophic levels. READ MORE

  6. 4. Analysis of quality characteristics of radiotherapeutic photon beams

    Author : Bo Nilsson; Stockholms universitet; []
    Keywords : Photon therapy; lepton contamination; photon contamination; surface dose; perturbation effects;

    Abstract : The lepton and photon contamination of high energy photon beams for radiation therapy has been investigated computationally and experimentally. The contaminating particles will effect the quality of the beam by increasing the surface dose, degrading the uniformity of the beam, broadening the penumbra, and increasing the energy imparted outside the useful beam. READ MORE

  7. 5. On Multistage Analysis of Transonic Compressors: From Axisymmetric Throughflow Time-Marching to Unsteady Three-Dimensional Methods

    Author : Stephane Baralon; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; shock; time-marching; deterministic; average-passage; multistage; fan; axisymmetric; 3D; unsteady; transonic; viscous; body force; stress; singularity; perturbation; throughflow; mixing-plane; modelling; finite-volume;

    Abstract : A throughflow time-marching finite-volume solver, capable of computing viscous transonic multistage compressor flows with embedded shocks, is presented. The behavior of the blade model, based on the blade mean surface flow tangency condition, was investigated for transonic flows. READ MORE