Sökning: "G Ågren"

Visar resultat 1 - 5 av 22 avhandlingar innehållade orden G Ågren.

  1. 1. Low Temperature Austenite Decomposition in Carbon Steels

    Författare :Albin Stormvinter; Annika Borgenstam; John Ågren; Peter Hedström; John G. Speer; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Carbon steels; Electron backscattered diffraction; Martensite; Microscopy; Microstructure; Thermodynamic modeling;

    Sammanfattning : Martensitic steels have become very important engineering materials in modern society. Crucial parts of everyday products are made of martensitic steels, from surgical needles and razor blades to car components and large-scale excavators. LÄS MER

  3. 2. 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. 3. Electrophysiology-based investigations of G protein-coupled receptor pharmacology

    Författare :Richard Ågren; Karolinska Institutet; Karolinska Institutet; []
    Nyckelord :;

    Sammanfattning : G protein-coupled receptors (GPCRs) constitute targets for ~34% of approved drugs. The muscarinic acetylcholine M2 receptor (M2R) activates G protein-coupled receptor inward rectifying potassium (GIRK) channels in the central nervous system and heart. Membrane potential modulates agonist potency at several GPCRs. LÄS MER

  5. 4. Population differentiation in Lythrum salicaria along a latitudinal gradient

    Författare :Katarina Olsson; Jon Ågren; Susan Kalisz; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ecology; additive genetic variance; clinal variation; evolutionary constraints; G matrix; genetic correlation; natural selection; pollen limitation; population differentiation; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi; ekologisk botanik; Ecological Botany;

    Sammanfattning : In this thesis, quantitative genetic approaches, common-garden experiments, and field studies were combined to examine patterns of population differentiation and the genetic architecture of characters of putative adaptive significance in the widely distributed perennial herb Lythrum salicaria. In this work, I (1) documented patterns of population differentiation in phenology, life-history, and morphology along latitudinal gradients at different geographical scales, (2) investigated the genetic architecture of phenology, flower morphology, and inflorescence size, and (3) combined estimates of phenotypic selection in the field with information on the genetic variance-covariance matrix (G) to examine potential constraints to adaptive evolution. LÄS MER

  7. 5. High-level modelling and local search

    Författare :Magnus Ågren; Pierre Flener; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Datavetenskap; Computer Science;

    Sammanfattning : Combinatorial optimisation problems are ubiquitous in our society and appear in such varied guises as DNA sequencing, scheduling, configuration, airline-crew and nurse rostering, combinatorial auctions, vehicle routing, and financial portfolio design. Their efficient solution is crucial to many people and has been the target for much research during the last decades. LÄS MER