Sökning: "Summer"

Visar resultat 16 - 20 av 517 avhandlingar innehållade ordet Summer.

  1. 16. Seed dormancy and germination in an ecological context : comparative studies of annual weeds

    Författare :Laila Karlsson; Per Milberg; Ken Thompson; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Asteraceae; Bidens; Compositae; deadnettle; Galinsoga; germination timing; Guizotia; evolution; Labiatae; Lamiaceae; Lamium; morphophysiological dormancy; Papaveraceae; Papaver; Parthenium; physiological dormancy; poppy; summer annual; Tagetes; Verbesina; winter annual; Biology; Biologi;

    Sammanfattning : Germination ecology studies, i.e. studies of interactions between characteristics of the seeds and environmental circumstances, provide understanding of spatial and temporal patterns of emergence of wild species, as weeds in the field. A large number of species have seed dormancy, i. LÄS MER

  3. 17. Summer cyanobacterial blooms in the Baltic Sea - implications for copepod recruitment

    Författare :Hedvig Hogfors; Sture Hansson; Wim Kimmerer; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Cyanobacteria; Calanoid copepods; Food web interactions; Harmful algae blooms; Zooplankton; Nodularin; Allelopathy; Baltic Sea; Biochemical markers; RNA-based indices; Acidification; Global Climate Change; Marine Ecology; marin ekologi;

    Sammanfattning : During summer, the Baltic Sea is subjected to the world’s largest cyanobacterial blooms. These blooms are linked to eutrophication and raise many questions concerning their effects on the ecosystem. To understand their impacts on the food web dynamics, it is essential to assess growth responses of grazers to these cyanobacteria. LÄS MER

  4. 18. Aspects of climate variability during winter and summer in Central America

    Författare :Tito Maldonado; Anna Rutgersson; Björn Claremar; Eric Alfaro; Jorve Amador; Rodrigo Caballero; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Meteorology; Meteorologi;

    Sammanfattning : .... LÄS MER

  5. 19. Long-term observations of polar mesosphere summer echoes using the ESRAD MST radar

    Författare :Maria Smirnova; Patrick Joseph Espy; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Rymdteknik; Space Technology;

    Sammanfattning : Polar Mesosphere Summer Echoes (PMSE) are strong radar echoes observed from altitudes of 80-90 km in polar regions, during summer time. PMSE are closely related to the fascinating atmospheric phenomenon known as noctilucent clouds (NLC). LÄS MER

  7. 20. Late Quaternary climate and environmental change in the summer rainfall region of South Africa : A study using trees and wetland peat cores as natural archives

    Författare :Elin Norström; Karin Holmgren; Michael Meadows; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; paleoclimate; Late Quaternary; pollen; stable isotopes; diatoms; phytoliths; dendroclimatology; South Africa; Physical geography; Naturgeografi; Physical Geography; naturgeografi;

    Sammanfattning : This thesis contributes with information on past climate and environmental changes in South Africa’s summer rainfall region. The study is based on multi-proxy analyses on wetland peat cores and analyses of stable isotope composition (δ13C, δ18O) and wood anatomy in cross sections from subtropical trees (Breonadia salicina). LÄS MER