Sökning: "darkness"

Visar resultat 16 - 20 av 88 avhandlingar innehållade ordet darkness.

1. 16. Analysis and development of strategies for magnetic resonance functional neuroimaging

   Författare :Peter Fransson; Karolinska Institutet; Karolinska Institutet; []
   Nyckelord :neuroimaging; human brain; functional activation; magnetic resonance imaging; cerebral blood oxygenation;

   Sammanfattning : This thesis focuses on strategies for oxygenation-sensitive MRI that are designed to measure alterations in brain physiology induced by changes in neuronal activity. In a first study, it was shown that the temporal evolution of BOLD MRI signal changes in response to both brief and sustained visual activation are equally well visible in FLASH and EPI recordings. LÄS MER

3. 17. Early life stages of brown trout - Anti-predator responses under warming winters

   Författare :Karl Filipsson; Eva Bergman; Ann Erlandsson; Johan Watz; Martin Österling; Neil Metcalfe; Karlstads universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; behaviour; climate; cortisol; development; egg incubation; embryo; gene expression; ice; light; mRNA; piscivorous; poikilotherm; salmonid; stress; temperature; Biology; Biologi;

   Sammanfattning : During winter, juvenile salmonids in boreal streams are vulnerable to predation, mainly from mammals and birds. Encounters with terrestrial predators can be reduced or avoided if fish limit activity to the darker periods of the day or to periods with surface ice. LÄS MER

4. 18. Circadian Rhythms in Moth Sex Pheromone Communication

   Författare :Germund von Wowern; Biologiska institutionen; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Physiology of invertebrates; växtparasitologi; Entomologi; plant parasitology; Entomology; Ecology; Ekologi; locomotor activity; social synchronisation; PDH; corazonin; PBAN; pheromone response; sex phermone; Lepidoptera; Ryggradslösa djurs fysiologi; calling behaviour; circadian rhythm;

   Sammanfattning : Sex pheromone communication and related physiological processes are regulated by circadian clock mechanisms in many moth species. This thesis includes studies of circadian rhythms in sexually relevant behaviours and communication in the Egyptian cotton leafworm Spodoptera littoralis, the turnip moth Agrotis segetum, the Indian meal moth Plodia interpunctella and the Mediterranean flour moth Ephestia kuehniella. LÄS MER

5. 19. An integrative approach to neurocardiologic mechanisms of heart disease risk in professional drivers : application of neuro-psycophysiologic and work environment models

   Författare :Reza Emdad; Karolinska Institutet; Karolinska Institutet; []
   Nyckelord :professional drivers; ischemic heart disease; EEC; ERP; TypeA behavior; Stress; Job Strain; headlight glare; night driving;

   Sammanfattning : Aim: This dissertation aims to apply, develop and integrate neurophysiologic, psychophysiologic, and work environment models, along with behavioral and biomedical risk factors" to provide insight into the neurocardiologic mechanisms of heart disease risk in professional drivers (PD). Methods: Subjects were male PD, age 25-52: 13 with ischemic heart disease(IHD), 12 hypertensives (HTN), 10 borderline hypertensives (BHTN) and 34 normotensives (NTN), and 23 non-PD controls. LÄS MER

7. 20. From Light to Dark : Electrical Phenomena in Cu(In,Ga)Se2 Solar Cells

   Författare :Piotr Szaniawski; Marika Edoff; Uwe Zimmermann; Jörgen Olsson; Thomas Walter; Uppsala universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Solar cells; Photovoltaics; Cu InGa Se2; CIGS; Electrical characterization; Teknisk fysik med inriktning mot elektronik; Engineering Science with specialization in Electronics;

   Sammanfattning : In Cu(In,Ga)Se2 (CIGS) solar cells the CIGS layer serves as the light absorber, growing naturally p-type. Together with an n-type buffer layer they form a p-n heterojunction. Typically, CdS is used as a buffer, although other, less toxic materials are investigated as alternatives. LÄS MER