Sökning: "Natural variation"

Visar resultat 11 - 15 av 1610 avhandlingar innehållade orden Natural variation.

  1. 11. Genetic variation in structured populations

    Författare :Marina Rafajlovic; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; genetic variation; varying population size; effective population size; mutation; recombination; migration; multiple paternity; geographic structure; tests of neutrality; gene tree; species tree;

    Sammanfattning : It is widely acknowledged that the process of speciation in the presence of gene flow between different ecotypes is common in nature. However, the mechanisms underlying speciation are not understood. LÄS MER

  3. 12. Improving interpretation by orthogonal variation : Multivariate analysis of spectroscopic data

    Författare :Hans Stenlund; Johan Trygg; Tom Fearn; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; OPLS; PLS; Multivariate Analysis; Orthogonal variation; Chemometrics; hyperspectral images; FTIR; NIR; spectroscopy; Chemistry; Kemi;

    Sammanfattning : The desire to use the tools and concepts of chemometrics when studying problems in the life sciences, especially biology and medicine, has prompted chemometricians to shift their focus away from their field‘s traditional emphasis on model predictivity and towards the more contemporary objective of optimizing information exchange via model interpretation. The complex data structures that are captured by modern advanced analytical instruments open up new possibilities for extracting information from complex data sets. LÄS MER

  4. 13. Variation Simulation Customized for Composites by Including FEM Simulations of Orthotropic Lamina

    Författare :Cornelia Jareteg; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Geometry assurance; FEM; Composites; Shell model; Process variation; Method of Influence Coefficients; Monte Carlo; Orthotropic material; Manufacturing; Tolerance analysis; Variation simulation; Spring-in; Tolerance analysis;

    Sammanfattning : The use of composite materials is increasing in many fields of production. Composite manufacturing, as well as other fields of production, suffers from uncertainties resulting in products that deviate from the specification. Geometry assurance is a common procedure used to keep the variations in product assemblies under control. LÄS MER

  5. 14. Natural variation in cold adaptation and freezing tolerance in Arabidopsis thaliana

    Författare :Antoine Bos; Pär Ingvarsson; Hans Stenøien; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Arabidopsis thaliana; cold acclimation; freezing tolerance; flowering time; latitudinal clines; genetic variation; evolutionary genetics; Molecular biology; Molekylärbiologi;

    Sammanfattning : Plants have spread to almost everywhere in the world. As they disperse, they meet many different environments to which they may be able to adapt. For a plant species to adapt to a new environment, genetic variation is needed. The individuals differ from each other in their genetic composition, which often means differences in phenotypes. LÄS MER

  7. 15. Geographic Distribution of Intra-specific Variation in Widespread Eurasian boreo-nemoral Woodland Herbs

    Författare :Torbjörn Tyler; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; kemotaxonomi. Växters fysiologi inte kärlväxter .; Plant genetics; Växtgenetik; morfologi; chemotaxonomy. Physiology of nonvascular plants; Systematisk botanik; taxonomi; phytogeography; morphology; taxonomy; historical biogeography; Systematic botany; allozymes; population differentiation; postglacial migration; genetic variation; geographic variation;

    Sammanfattning : Many woodland plant species have huge distribution areas covering large parts of the Eurasian continent including areas that were glaciated during the last glacial period. In the present thesis, the geographic distribution of variation within such species is investigated and discussed in relation to glacial survival and post-glacial migration, dispersal ability, breeding system and levels of gene-flow between populations and related species, and various methods to measure and analyse genetic variation. LÄS MER