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Visar resultat 11 - 15 av 38 avhandlingar som matchar ovanstående sökkriterier.

  1. 11. Genetic variation and population differentiation in the forest herb Lathyrus vernus (Fabaceae)

    Författare :Katarina Schiemann; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; chemotaxonomy. Physiology of nonvascular plants; Systematisk botanik; taxonomi; morfologi; kemotaxonomi. Växters fysiologi inte kärlväxter .; taxonomy; morphology; phytogeography; inbreeding depression; Systematic botany; small population size; marginality; reproductive characters; leaflet shape; allozymes; Lathyrus vernus; genetic variation;

    Sammanfattning : In the present thesis, I investigated patterns of genetic variation in the forest herb Lathyrus vernus (Fabaceae), using plant material from different-sized populations representing three geographically separated regions: central Europe, southern and central Sweden. My studies included presumably neutral or weakly selected characters (allozymes and leaflet shape) as well as characters that should be under strong directional selection (e. LÄS MER

  3. 12. Population size, viability and genetic diversity in the orchid Gymnadenia conopsea

    Författare :Linus Söderquist; Nina Sletvold; Sophie Karrenberg; Hans Jacquemyn; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; demography; extinction probability; genetic diversity; genetic rescue; genetic structure; Gymnadenia conopsea; orchid conservation; population viability; population size; Biology with specialization in Ecological Botany; Biologi med inriktning mot ekologisk botanik;

    Sammanfattning : In this thesis, I combined controlled crosses with genetic and demographic data to examine how a main conservation value indicator, population size, was associated with estimates of population viability. I focused on the still common, but decreasing, perennial orchid Gymnadenia conopsea at two spatial scales—locally on the island Öland, in SE Sweden, and regionally across Scandinavia. LÄS MER

  4. 13. The role of microclimate for the performance and distribution of forest plants

    Författare :C. Johan Dahlberg; Kristoffer Hylander; Johan Ehrlén; Jason D. Fridley; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; performance; microclimate; spatial scales; continental; landscape; distribution patterns; distribution limits; phenology; vegetative development; reproductive development; vital rates; population growth rate; vascular plants; bryophytes; distribution modelling; Plant Ecology; växtekologi;

    Sammanfattning : Microclimatic gradients may have large influence on individual vital rates and population growth rates of species, and limit their distributions. Therefore, I focused on the influence of microclimate on individual performance and distribution of species. LÄS MER

  5. 14. Aspects of common principal components

    Författare :Toni Duras; Thomas Holgersson; Jönköping University; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : The focus of this thesis is the common principal component (CPC) model, the generalization of principal components to several populations. Common principal components refer to a group of multidimensional datasets such that their inner products share the same eigenvectors and are therefore simultaneously diagonalized by a common decorrelator matrix. LÄS MER

  7. 15. Latent variable models for multivariate survival and count data

    Författare :Samuli Ripatti; David Clayton; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; matematisk statistik; Mathematical Statistics;

    Sammanfattning : This thesis consists of three papers on multivariate frailty models and one paper on the use of latent class models in genetic association studies. The common theme through the four papers is the use of latent variables to capture complex dependence structures in the data. LÄS MER