Avancerad sökning

Visar resultat 1 - 5 av 232 avhandlingar som matchar ovanstående sökkriterier.

1. 1. Carbon metabolism in clear-water and brown-water lakes

   Författare :Jenny Ask; Jan Karlsson; Mats Jansson; Rolf Vinebrooke; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; clear-water lakes; brown-water lakes; primary production; bacterial production; benthic; pelagic; net ecosystem production; allochthonous organic carbon; CO2; DOC; Physical geography; Naturgeografi; Freshwater ecology; Limnisk ekologi; limnologi; Limnology; naturgeografi; Physical Geography;

   Sammanfattning : The trophic state of lakes is commonly defined by the concentration of nutrients in the water column. High nutrient concentrations generate high phytoplankton production, and lakes with low nutrient concentrations are considered low-productive. LÄS MER

3. 2. Effects of temperature and terrestrial carbon on primary production in lake ecosystems

   Författare :Mohammed Hamdan; Jan Karlsson; Pär Byström; Erin R. Hotchkiss; Lars-Anders Hansson; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; lakes; primary production; benthic; pelagic; carbon dioxide limitation; light limitation; nutrient limitation; browning; warming; allochthonous carbon; grazing; trophic cascades;

   Sammanfattning : Climate warming is predicted to affect northern lake food webs in two ways: (1)directly via changes in water temperature and ice conditions, and (2) indirectlyvia changes in catchment characteristics and processes that influence input ofallochthonous coloured dissolved organic matter (cDOM) and nutrients. Input ofcDOM increases carbon dioxide (CO2) availability, causes brownification andreduced light conditions, and may increase nutrient availability especially forpelagic primary producers. LÄS MER

4. 3. Primary Production in African Drylands : Quantifying Supply and Demand Using Earth Observation and Socio-ecological Data

   Författare :Abdulhakim Abdi; Institutionen för naturgeografi och ekosystemvetenskap; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; SAMHÄLLSVETENSKAP; SOCIAL SCIENCES; Net primary production; Africa; Drylands; Coupled human and natural systems; Human-Environment Relations; Food security; Earth observation; Remote Sensing;

   Sammanfattning : The human-environment connection in the mostly rural drylands of sub-Saharan Africa forms a complex, interlinked system that provides ecosystem services. This system is susceptible to climatic variability that impacts the supply of its products, and high population growth, which impacts the demand for these products. LÄS MER

5. 4. Primary HIV-1 infection : diagnostic, prognostic, and therapeutic aspects

   Författare :Stefan Lindbäck; Karolinska Institutet; Karolinska Institutet; []
   Nyckelord :primary HIV- I infection; diagnosis; prognosis; HIV-RNA; antiretroviral treatment; primary HIV-1 infection; diagnosis; prognosis; HIV-RNA; antiretroviral treatment;

   Sammanfattning : Primary HIV-1 infection (PHI) is usually defined as a mononucleosis-like illness associated with seroconversion to HIV. In earlier studies using 1st generation antibody tests, the duration of the 'window period' from infection to detection of specific HIV-antibodies, could be 2 to 3 months, or longer. LÄS MER

7. 5. Genetics of primary immunodeficiency diseases

   Författare :Javad Mohammadi; Karolinska Institutet; Karolinska Institutet; []
   Nyckelord :HLA Antigens; IgA deficiency; Common variable immunodeficiency; immunogenetics; immunodeficiency; TACI;

   Sammanfattning : Selective IgA deficiency (IgAD) (serum IgA concentration of T), which abolished expression of the TACI molecule. In addition, we found the previously recognized C104R and C172Y mutations in a heterozygous form in 2 patients with CVID and one, novel, heterozygous P42T mutation. LÄS MER