Sökning: "trait"

Visar resultat 16 - 20 av 557 avhandlingar innehållade ordet trait.

1. 16. Sexual conflict and selection on pistil and pollen traits

   Författare :Josefin Madjidian; Biologiska institutionen; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Antagonistic trait; Collinsia heterophylla; delayed stigma receptivity; direct cost; first-donor advantage; gender bias; heritability; indirect benefit; mate choice; mixed-mating system; paternal diversity; pollen competition; pollen deposition; pollen load size; pollen tube growth rate; self-compatibility; semantics; sexual conflict; sexual selection; sexually antagonistic co-evolution;

   Sammanfattning : The incidence of sexual selection in plants is today acknowledged, however, just as in animals, evolution and maintenance of mate choice is gravely underexplored. Moreover, the potential for sexual conflicts to occur in plants has only been assessed empirically to a very limited degree. LÄS MER

3. 17. Pollinator-mediated selection and the evolution of floral traits in orchids

   Författare :Judith Trunschke; Jon Ågren; Nina Sletvold; Allan G. Ellis; Uppsala universitet; []
   Nyckelord :Among-population variation; Ecotype; Field experiment; Floral evolution; Germination; Local adaptation; Orchidaceae; Platanthera bifolia; Phenotypic selection; Pollination; Reciprocal transplant; Trait manipulation; Biology with specialization in Ecological Botany; Biologi med inriktning mot ekologisk botanik;

   Sammanfattning : In this thesis, I combined manipulations of traits and pollination environment with analysis of phenotypic selection to examine causes of variation in strength and mode of selection on floral traits, and I conducted a reciprocal sowing experiment to test for local adaptation in germination success. I tested the following predictions (1) the opportunity for selection, and the strength of pollinator-mediated and net selection increase with increasing pollen limitation, (2) the effects of traits affecting pollinator attraction and traits affecting pollination efficiency are non-additive and this leads to pollinator-mediated correlational selection, (3) the effects of spur length on pollen removal, pollen receipt, and female fitness differ between populations with short-tongued and populations with long-tongued pollinators, and (4) local adaptation at the stage of germination contributes to the maintenance of ecotypes growing in grasslands and woodlands, respectively. LÄS MER

4. 18. Diagnostic Aspects of Fear of Childbirth

   Författare :Margareta Zar; Linköpings universitet; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Fear of childbirth; W-DEQ; psychometrics; diagnostic test; anxiety; anxiety disorders; state fear; trait fear; delivery; mode of delivery; obsteric complications; riskfactor;

   Sammanfattning : The first study presents the theoretical background of the Wijma Delivery Expectancy/Experience Questionnaire (W-DEQ) and an examination of this new instrument's construct validity and reliability. The W-DEQ has good reliability and measures the construct "fear of childbirth", when compared with other questionnaires. LÄS MER

5. 19. Does the way in which we perceive the world make us susceptible to anxiety?

   Författare :Billy Jansson; Lars-Göran Öst; Lars-Gunnar Lundh; Marcel Van den Hout; Stockholms universitet; []
   Nyckelord :SAMHÄLLSVETENSKAP; SOCIAL SCIENCES; Preattentive processing; selective attention; trait anxiety; defensiveness; emotional responses; emotional vulnerability; Psychology; Psykologi;

   Sammanfattning : One major focus of anxiety research in recent years has been the identification of cognitive factors that promote increased vulnerability to anxiety. Cognitive formulations propose that anxiety is characterised by an increased tendency to attend to negatively valenced emotional information, and that this bias may play a causal role in the development and maintenance of clinical anxiety. LÄS MER

7. 20. Quantitative Genetics and Genome Structure in a Wild Population: the Use of a Great Reed Warbler Pedigree

   Författare :Mikael Åkesson; Biologiska institutionen; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; genome mapping ; AFLP; microsatellite; synteny; heterochiasmy; recombination; chicken; great reed warbler ; bird; Genetics; cytogenetics; Genetik; cytogenetik; Animal ecology; trait correlation ; Djurekologi; animal model ; selection; Djurs anatomi och morfologi; animal morphology; Animal anatomy; heritability;

   Sammanfattning : Long-term studies of birds play an important role in the understanding of quantitative traits in natural populations. The relative ease by which individual birds can be monitored and caught in the wild enable us collect detailed information from individuals throughout their life time, sometimes from several generations in a population. LÄS MER