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Visar resultat 16 - 20 av 103 avhandlingar som matchar ovanstående sökkriterier.

  1. 16. Taxonomy, phylogeny, and secondary sexual character evolution of diving beetles, focusing on the genus Acilius

    Författare :Johannes Bergsten; Anders N. Nilsson; Jyrki Muona; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Biology; antagonistic coevolution; arms race; sexual conflict; diving beetle; Dytiscidae; Coleoptera; taxon sampling; long-branch attraction; parsimony; Bayesian analysis; taxonomic revision; Biologi; Biology; Biologi;

    Sammanfattning : Sexual conflict can lead to antagonistic coevolution between the sexes, but empirical examples are few. In this thesis secondary sexual characters in diving beetles are interpreted in the light of sexual conflict theory. LÄS MER

  3. 17. Precambrian Crustal Evolution of the Rehoboth Province, Southern Africa

    Författare :Valby van Schijndel; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Rehoboth Province; Rehoboth Basement Inlier; Kaaien Terrane; Dwyka Diamictite; U–Pb; Sm–Nd; Lu–Hf; Ar–Ar Geochronology; Oxygen isotopes; Zircon; Baddeleyite;

    Sammanfattning : This thesis uses U-Pb, Sm-Nd Lu-Hf, Ar-Ar and Oxygen isotope data on well-documented rock samples, to investigate crustal evolution of the Precambrian Rehoboth Province of Southern Africa. This province is defined by its smooth magnetic character, reflecting deep magnetic basement in contrast to the adjoining mobile belts and the Kaapvaal Craton. LÄS MER

  4. 18. Evolution and ecology of Baltic late Ordovician univalved molluscs

    Författare :Jan Ove Rõysi Ebbestad; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Earth sciences; Geovetenskap; Earth sciences; Geovetenskap; Historical Geology and Paleontology; historisk geologi och paleontologi;

    Sammanfattning : Univalved molluscs (Gastropoda and Tergomya) are common fossils in the Palaeozoic succession across Baltoscandia, but most of the more embracive descriptive works on this group appeared before or near the turn of the 19th century. The study presented here aims at revision and description of some Baltoscandian late Ordovician/early Silurian univalved molluscs with emphasis on their shell morphology. LÄS MER

  5. 19. The Quest for Functional Quasi-Species in Glutathione Transferase Libraries

    Författare :Arna Rúnarsdóttir; Bengt Mannervik; Ralf Morgenstern; Uppsala universitet; []
    Nyckelord :glutathione transferase; directed evolution; multivariate analysis; quasi-species; isothiocyanates; Biokemi; Biochemistry;

    Sammanfattning : Glutathione transferases (GSTs) are good candidates for investigations of enzyme evolution, due to their broad substrate specificities and structural homology. The primary role of GSTs is to act as phase II detoxifying enzymes protecting the cell from toxic compounds of both endo- and exogenous origins. LÄS MER

  7. 20. New Technology-Based Firms and Industrial Dynamics Evidence from the Technological System of Biomaterials in Sweden, Ohio and Massachusetts

    Författare :Annika Rickne; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; firm development; policy; industrial dynamics; technological system; growth; connectivity; management; biomaterial; new technology-based firm; co-evolution;

    Sammanfattning : The aim of this thesis is to enhance the understanding of the relationship between industrial dynamics and new technology-based firms (henceforth NTBFs). For a population of biomaterials NTBFs in Sweden, Ohio and Massachusetts, we have analyzed two facets of this issue. LÄS MER