Sökning: "Distributed Morphology"

Visar resultat 16 - 20 av 62 avhandlingar innehållade orden Distributed Morphology.

1. 16. Growth of ZnO/GaN distributed Bragg reflectors by plasma-assisted molecular beam epitaxy

   Författare :David Adolph; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; Oxides; GaN; distributed Bragg reflector; MBE; molecular beam epitaxy; ZnO; Nitrides; DBR;

   Sammanfattning : This thesis describes epitaxial growth of ZnO/GaN distributed Bragg reflectors by hybrid plasma-assisted molecular beam epitaxy on GaN(0001). The unique hybrid approach employed the same growth chamber for continuous growth of both ZnO and GaN without exposing the layers to the ambient conditions. LÄS MER

3. 17. The morphology and evolutionary significance of the anomalocaridids

   Författare :Allison Daley; Graham E. Budd; Nigel C. Hughes; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; anomalocaridids; Cambrian; Burgess Shale; exceptional preservation; palaeontology; Historical geology and palaeontology; Historisk geologi och paleontologi; Historical Geology and Paleontology; Historisk geologi och paleontologi;

   Sammanfattning : Approximately 600 to 500 million years ago, a major evolutionary radiation called the “Cambrian Explosion” gave rise to nearly all of the major animal phyla known today. This radiation is recorded by various fossil lagerstätten, such as the Burgess Shale in Canada, where soft-bodied animals are preserved in exquisite detail. LÄS MER

4. 18. On Speciation in Birds – Genomic Signatures across Space and Time

   Författare :Martin Stervander; MEMEG; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; colonization; islands; isolation; introgressive hybridization; sympatry; natural selection; bill morphology; coalescence-based analyses; DNA sequencing; birds; divergence; Speciation;

   Sammanfattning : The process of speciation is a cornerstone in evolutionary biology. In Darwin’s On the Origin of Species, he described how he imagined that a new species would evolve to fill an empty niche. This focus on ecology shifted with Mayr towards the importance of isolation, and for many decades the geographic modes of speciation were debated. LÄS MER

5. 19. The Human Spiral Ganglion

   Författare :Sven Tylstedt; Umeå universitet; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Otorhinolaryngology; human spiral ganglion; ultrastructural morphology; neural interaction; synaptophysin; connexin; membrane specializations; synapse; gap junction; tight junction; Otorhinolaryngologi; Otorhinolaryngology; Otorhinolaryngologi; Oto-Rhino-Laryngology; oto-rhino-laryngologi;

   Sammanfattning : Our knowledge of the fine structure of the Human Spiral Ganglion (HSG) is still inadequate and new treatment techniques for deafness using electric stimulation, call for further information and studies on the neuronal elements of the human cochlea. This thesis presents results of analyses of human cochlear tissue and specimens obtained during neurosurgical transpetrosal removal of life-threatening meningeomas. LÄS MER

7. 20. Rarity in boreal stream: patterns, causes and consequences

   Författare :Per-Ola Hoffsten; Bo W. Svensson; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ecology; Central Sweden; site occupancy; dispersal limitation; natural disturbances; recolonization; flight-morphology; metapopulation; habitat stability; spring specialists; Crunoecia irrorata; niche limitation; Isogenus nubecula; nestedness; longitudinal distribution; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi; zooekologi; Animal Ecology;

   Sammanfattning : Patterns of site occupancy among boreal stream insects were studied in central Sweden with focus on sparsely distributed species and the role of dispersal and niche limitations.In the study of dispersal limitation, I found that effects of an extraordinarily harsh winter in small to medium-sized streams were strongest in sites located in small streams and far from lake outlets. LÄS MER