Search for dissertations about: "apposition"

Showing result 1 - 5 of 17 swedish dissertations containing the word apposition.

2. 1. Adaptations for nocturnal vision in insect apposition eyes

   Author : Birgit Greiner; Biologiska institutionen; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; temporal and spatial summation; optical and neural adaptations; theoretical modelling.; Djurs anatomi och morfologi; Zoologi; dim light; vision; landmark navigation; nocturnal bees and wasps; Zoology; Animal anatomy; animal morphology;

   Abstract : Due to our own preference for bright light, we tend to forget that many insects are active in very dim light. The reasons for nocturnal activity are most easily seen in tropical areas of the world, where animals face severe competition for food and nocturnal insects are able to forage in a climate of reduced competition and predation. READ MORE

4. 2. Ommatidial adaptations for vision in nocturnal insects

   Author : Rikard Frederiksen; Biologiska institutionen; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Gain of transduction; Information rate; Signal-to-noise ratio; Apposition eye; Optical sensitivity; Nocturnal insects; Superposition eye; Vision;

   Abstract : Nocturnal vision is a demanding task for insects with small eyes. As it gets dimmer the noise imposed by the stochastic nature of photon arrival makes vision unreliable. Despite this, there are quite a number of animal species that are active at night and apparently see well. READ MORE

5. 3. Changes in bone mass and skeletal structure in the postmenopausal period

   Author : Henrik Ahlborg; Ortopedi - klinisk och molekylär osteoporosforskning; []
   Keywords : MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; orthopaedics; Surgery; hormone replacement therapy.; physical activity; bone strength; bone size; bone loss; longitudinal; Menopause; bone mineral density; traumatology; Kirurgi; ortopedi; traumatologi;

   Abstract : The aim of this thesis was to evaluate long-term changes in bone mass and skeletal structure in the forearm in the peri- and postmenopausal period. 156 premenopausal women, at baseline aged 48 years, not taking medications and without disease processes known to interfere with bone metabolism, were followed through menopause by measurements of bone mass and skeletal structure at the cortical site of the distal radius by single photon absorptiometry, on average every second year until age 72. READ MORE

6. 4. Visual ecology of insect superposition eyes

   Author : Pär A Brännström; Biologiska institutionen; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Animal physiology; tiger beetle; hawkmoth; mayfly; insect; visual ecology; eye design; vision; compound eye; Djurfysiologi;

   Abstract : In the superposition compound eye each rhabdom (light sensitive unit) receives light through many ommatidial facets, while in the apposition compound eye every rhabdom receives light from a single facet. The superposition design increases photon capture, which is an advantage in dark environments. READ MORE

7. 5. Endovascular Repair of Abdominal Aortic Aneurysms. Aspects on a Novel Technique

   Author : Martin Malina; Malmö Institutionen för kliniska vetenskaper; []
   Keywords : MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; migration.; endoleak; stent; stentgraft; endovascular repair; Aneurysm; therapy; Surgery; orthopaedics; traumatology; Kirurgi; ortopedi; traumatologi;

   Abstract : A new concept of treating abdominal aortic aneurysms was studied during a three-year period. Instead of open repair, graft insertion was accomplished endovascularly from the groins. The graft was attached by expandable stents to the non-dilated infrarenal aorta, i.e. READ MORE