Sökning: "plasticity"

Visar resultat 26 - 30 av 634 avhandlingar innehållade ordet plasticity.

  1. 26. Astrocyte-mediated short-term synaptic depression

    Författare :My Andersson; Göteborgs universitet; []
    Nyckelord :glutamate; glia; plasticity; synapse; hippocampus;

    Sammanfattning : Short-term synaptic plasticity, the activity-dependent regulation of synaptic efficacy that occurs in the timeframe of milliseconds to seconds, is a fundamental property of the synapse, mostly attributed to changes in release probability. These changes are commonly ascribed to intrinsic mechanisms in the presynaptic terminal and to different transmitters acting on the presynaptic terminal. LÄS MER

  3. 27. Neurotrophic factors and neuronal plasticity

    Författare :Sten Linnarsson; Karolinska Institutet; Karolinska Institutet; []
    Nyckelord :;

    Sammanfattning : The neurotrophic factors were originally discovered because of their ability to rescue neurons during a period of naturally occurring programmed cell death. This gave rise to the neurotrophic factor hypothesis which states that specific target-derived factors protect and support subpopulations of innervating neurons, thereby regulating the pattern and quantity of innervation properly for each target tissue. LÄS MER

  4. 28. Modeling of phase transformations and cyclic plasticity in pearlitic steels

    Författare :Björn Andersson; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Phase transformations; TRIP; Pearlitic steel; FEM; Cyclic plasticity; Homogenization;

    Sammanfattning : The low rolling resistance in railway transportation is a key factor for its high efficiency, but it comes at the price of very high contact pressure between the rail and wheel. Due to the high stresses and the large number of load cycles during railway operation, both the rail and the wheel can be susceptible to fatigue crack initiation and propagation. LÄS MER

  5. 29. Phenotypic responses of zooplankton to variable conditions

    Författare :Marcus Lee; Enhet akvatisk ekologi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Multiple threats; Plasticity; Risk-Spreading; sexual conflict; ultraviolet radiation; Daphnia; Copepods;

    Sammanfattning : Organisms are continually challenged by multiple threats in the environment, and such threats are seldom constant in either time or space. Therefore, organisms must maintain physiological, behavioural, morphological and life- history adaptations across environments to prevent reductions in fitness. LÄS MER

  7. 30. Modelling of cyclic and viscous behaviour of thermomechanically loaded pearlitic steels; Application to tread braked railway wheels

    Författare :Ali Esmaeili; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; rolling contact fatigue; plasticity; tread braking; full-scale brake rig testing; Railway wheels; finite element analyses; pearlitic steel; viscoplasticity; ratchetting; phase transformations;

    Sammanfattning : In service, railway wheel and rail materials are subjected to high stresses and, in some cases, elevated temperatures. The high stresses are caused by the rolling contact between wheel and rail. Furthermore, heat generated from tread braking and/or sliding between wheel and rail gives additional stress due to constrained thermal expansion. LÄS MER