Sökning: "edge effect"

Visar resultat 1 - 5 av 261 avhandlingar innehållade orden edge effect.

  1. 1. Living on the edge : effectiveness of buffer strips in protecting biodiversity on boreal riparian forests

    Författare :Kristoffer Hylander; Christer Nilsson; Bengt Gunnar Jonsson; Ellen Macdonald; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ecology; boreal forest; bryophyte; buffer strip; ecological boundary; edge effect; headwater stream; land snail; liverwort; moss; phytometer; riparian forest; substrate; terrestrial gastropod; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi; ekologisk botanik; Ecological Botany;

    Sammanfattning : The objective of this thesis is to evaluate the ecological consequences of buffer strip retention on riparian and terrestrial biodiversity. Earlier studies on forest buffer strips have evaluated their effectiveness in relation to water quality and aquatic biota. However, forests along streams are species rich habitats for many organism groups. LÄS MER

  3. 2. Forest edges in boreal landscapes - factors affecting edge influence

    Författare :Ulrika Jansson; Per-Anders Esseen; Mats Nilsson; Timo Kuuluvainen; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; aerial photographs; edge contrast; edge density; edge length; fetch size; forest fragmentation; lichen growth; line intersect sampling; pendulous lichen; photo interpretation; skogskant; flygbild; kantlängd; lav; Terrestrial ecology; Terrestisk ekologi; ekologisk botanik; Ecological Botany;

    Sammanfattning : The boreal forest in Fennoscandia has been subjected to major loss and fragmentation of natural forests due to intensive forestry. This has resulted in that forest edges are now abundant and important landscape features. Edges have documented effects on the structure, function and biodiversity in forests. LÄS MER

  4. 3. Interaction between electronic and vibrational edge states in graphene

    Författare :Anton Vikström; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; collective excitations; quantum acous- tics; quantum Hall effect; edge waves; graphene; solitons;

    Sammanfattning : A sheet of graphene in a magnetic field perpendicular to the sheet has electronic edge states with nonzero velocities. These edge states are localized to the edge of the sheet on the order of the magnetic length. LÄS MER

  5. 4. Bridge Overhang Slabs with Edge Beams : LCCA and Structural Analysis for the Development of New Concepts

    Författare :José Javier Veganzones Muñoz; Costin Pacoste; Raid Karoumi; Lars Pettersson; Rui Vaz Rodrigues; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Overhang slab; Edge beam; Life-cycle Cost Analysis; Non-linear FE-analysis; Design methods; Shear force; Failure mode; Effective width; Minimal width.; Konsolplattor; Kantbalkar; Livscykelkostnadsanalys; Icke-linjär FE-analys; Dimensioneringsmetoder; Tvärkrafter; Brott; Fördelningsbredd; Minimal bredd.; Bro- och stålbyggnad; Structural Engineering and Bridges;

    Sammanfattning : Bridge edge beams are associated with high life-cycle costs because of the need of maintenance, which also causes traffic disturbances. For this reason, the Swedish Transport Administration started a project to find better solutions. One of the proposals was a design without edge beam. LÄS MER

  7. 5. Electron Transport in Low Dimensional Systems

    Författare :Peter Ramvall; Fasta tillståndets fysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; high mobility; low-dimensional structures; III-V semiconductors; quantum wells; heterojunctions; quantum Hall effect; edge channels; Shubnikov-de Haas effect; alloy-disorder scattering; Y-branch switch; two dimensional electron gas; Fysik; Fysicumarkivet A:1996:Ramvall; Physics; spin splitting; mag;

    Sammanfattning : This thesis consists of experimental studies of transport properties in high mobility two dimensional electron gases (2DEGs). Two material systems are used, an AlGaAs/GaAs heterojunction and a GaInAs/InP quantum well. LÄS MER