Search for dissertations about: "reproductive output"

Showing result 1 - 5 of 41 swedish dissertations containing the words reproductive output.

  2. 1. Breeding System Evolution and Pollination Success in the Wind-Pollinated Herb Plantago maritima

    Author : Emil Nilsson; Jon Ågren; Pia Mutikainen; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Biology; Breeding system; mating system; gynodioecy; male sterility; reproductive output; self-compatibility; self-incompatibility; wind-pollination; founder event; genetic structure; Biologi; Biology; Biologi; ekologisk botanik; Ecological Botany;

    Abstract : In this thesis, I examined variation in sex expression and mating patterns in the sexually polymorphic, wind-pollinated herb Plantago maritima. With a combination of field studies, greenhouse experiments, and genetic analyses, I (a) examined factors influencing sex ratio variation in gynodioecious plants (in which hermaphrodites and females coexist), (b) discovered variation in breeding system, (c) investigated density-dependence of seed production, and (d) documented genetic variation within and among populations close to the northern range margin in Europe. READ MORE

  4. 2. Fetal Cardiac Function and Venous Circulation - Experiences with Velocity Vector Imaging

    Author : Charlotte Dahlbäck; Urogynekologi och reproduktionsfarmakologi; []
    Keywords : MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; pregnancy; fetus; strain; speckle tracking; cardiac function; umbilical vein; venous; ductus venosus; Doppler;

    Abstract : Placental dysfunction resulting in intrauterine growth restriction (IUGR) is a common complication of pregnany and severe IUGR, with ensuing fetal hypoxia is an important cause of perinatal mortality and morbidity. Doppler studies of fetal and maternal vessels are routinely used for fetal surveillance and alterations in fetal venous blood flow has been demonstrated as a late sign of fetal compromise. READ MORE

  5. 3. Intraovarian mechanisms influencing the human corpus luteum

    Author : Ulrika Ottander; Torbjörn Hillensjö; Umeå universitet; []
    Keywords : MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Corpus luteum; steroidreceptors; progesterone; LH hCG; PGF2α; ultrasonography;

    Abstract : Introduction: The human corpus luteum (CL) is a transient endocrine gland, only functionally active for about 14 days. Its principal function is to produce and secrete progesterone and thereby support the endometrium for implantation of a blastocyst and prevent rejection of the developing embryo. READ MORE

  6. 4. Plant-animal interactions and seed output of two insectpollinated herbs

    Author : Anna R. Waites; Umeå universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; plant reproduction; pollen limitation; pollinator behaviour; heterostyly; seed predation; Lythrum salicaria; Pedicularis palustris; stigma receptivity; self-pollen; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi;

    Abstract : I combined comparative and experimental studies in the field and in the greenhouse to examine factors influencing reproductive success in two insect-pollinated herbs, the tristylous, selfincompatible perennial Lythrum salicaria and the self-compatible, biennial Pedicularis palustris. More specifically, I explored (i) the effects of plant population characteristics on the intensity and outcome of interactions with pollinators and seed predators, (ii) whether flower morphology affects duration of stigma receptivity, and (iii) whether damage-induced reduction in floral display reduces pollinator visitation and increases pollen limitation. READ MORE

  7. 5. Coping with environmental change : Lessons from isotope studies in a sentinel species

    Author : Matias Ledesma; Agnes Karlson; Marleen De Troch; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; stable isotope; compound-specific nitrogen stable isotope analysis; trophic niche; harmful algae blooms; contaminants; stress; reproductive success; environmental change; Baltic Sea; marin ekologi; Marine Ecology;

    Abstract : Adaptive evolution and phenotypic plasticity are two key mechanisms by which natural populations avoid extinction in the face of environmental change. Evolutionary young systems, such as the Baltic Sea with low species diversity and steep environmental gradients, are good models for studying how wild populations cope with environmental changes, such as climate-induced alterations in food supply and exposure to environmental contaminants. READ MORE