Sökning: "C and N cycling"

Visar resultat 1 - 5 av 46 avhandlingar innehållade orden C and N cycling.

1. 1. Allopregnanolone effects in women : clinical studies in relation to the menstrual cycle, premenstrual dysphoric disorder and oral contraceptive use

   Författare :Erika Timby; Marie Bixo; Torbjörn Bäckström; Anna-Carin N Wihlbäck; C Neill Epperson; Umeå universitet; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Allopregnanolone; GABAA receptor; menstrual cycle; premenstrual dysphoric disorder; saccadic eye velocity; oral contraceptives; hypothalamic amenorrhea;

   Sammanfattning : Background: Premenstrual dysphoric disorder (PMDD) affects 3–8% of women in fertile ages. Combined oral contraceptives (OCs) are widely used and some users experience adverse mood effects. The cyclicity of PMDD symptoms coincides with increased endogenous levels of allopregnanolone after ovulation. LÄS MER

3. 2. Physiology of Adventure Racing : with emphasis on circulatory response and cardiac fatigue

   Författare :C. Mikael Mattsson; Björn Ekblom; Keith P George; Gymnastik- och idrottshögskolan; Karolinska Institutet; Karolinska Institutet; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; cardiovascular drift; cardiac fatigue; adventure race; cardiac biomarkers; cardoac function; exercise echocardiography; Physiology; Fysiologi; Cardiology; Kardiologi; Sports; Idrott; Medicin Teknik; Medicine Technology;

   Sammanfattning : The overall aims of this thesis were to elucidate the circulatory responses to ultra-endurance exercise (Adventure Racing), and furthermore, to contribute to the clarification of the so called “exercise-induced cardiac fatigue” in relation to said exercise. An Adventure race (AR) varies in duration from six hours to over six days, in which the participants have to navigate through a number of check-points over a pre-set course, using a combination of three or more endurance/outdoor sports, e. LÄS MER

4. 3. Mitochondria, contractility and Ca2+ handling : cardiac and skeletal muscle adaptations in health and disease

   Författare :Daniel C Andersson; Karolinska Institutet; Karolinska Institutet; []
   Nyckelord :;

   Sammanfattning : Contractility is a fundamental feature of skeletal and cardiac muscles. An indispensable step in the cellular signal for contraction is a transient elevation in cytoplasmic free [Ca2+] ([Ca2+]i). Both the production of contractile force and Ca2+ handling processes are highly energy demanding. LÄS MER

5. 4. The Nitrogen Cycle in Soil - Climate Impact and Methodological Challenges in Natural Ecosystems

   Författare :Anna-Karin Björsne; Göteborgs universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Nitrogen cycle; 15N tracing experiments; gross N transformation rates; climate change; climate treatments; mineralization; nitrification; forest fertilization; nitrous oxide emissions; boreal forest soil; tree species; soil organic matter; C:N ratio;

   Sammanfattning : Nitrogen (N) is a fundamental element for life, and limiting in many terrestrial ecosystems. In non-N-fertilized ecosystems, the N inputs can be low, and the nutrient availability for plants is determined by the internal cycling of N. LÄS MER

7. 5. Varved lake sediments and diagenetic processes

   Författare :Veronika Gälman; Ingemar Renberg; Daniel Conley; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Varved annually laminated lake sediment; diagenesis; varve appearance; iron; sulfur; chemical speciation; iron cycling; carbon; nitrogen; stabile isotopes; δ13C; δ15N; Earth sciences; Geovetenskap;

   Sammanfattning : Varved (annually laminated) sediments are of great interest for inference of past environmental conditions, as they provide dated records with high time resolution. After deposition, the sediment varves are affected by diagenesis; i.e., chemical, physical and biological changes that occur within the sediment. LÄS MER