3 resultados para Controlled Branching Process
em Nottingham eTheses
Resumo:
This paper considers a stochastic SIR (susceptible-infective-removed) epidemic model in which individuals may make infectious contacts in two ways, both within 'households' (which for ease of exposition are assumed to have equal size) and along the edges of a random graph describing additional social contacts. Heuristically-motivated branching process approximations are described, which lead to a threshold parameter for the model and methods for calculating the probability of a major outbreak, given few initial infectives, and the expected proportion of the population who are ultimately infected by such a major outbreak. These approximate results are shown to be exact as the number of households tends to infinity by proving associated limit theorems. Moreover, simulation studies indicate that these asymptotic results provide good approximations for modestly-sized finite populations. The extension to unequal sized households is discussed briefly.
Resumo:
Dendrites form the major components of neurons. They are complex branching structures that receive and process thousands of synaptic inputs from other neurons. It is well known that dendritic morphology plays an important role in the function of dendrites. Another important contribution to the response characteristics of a single neuron comes from the intrinsic resonant properties of dendritic membrane. In this paper we combine the effects of dendritic branching and resonant membrane dynamics by generalising the "sum-over-trips" approach [Abbott, L.F., Fahri, E., Gutmann, S.: The path integral for dendritic trees. Biological Cybernetics 66, 49--60 (1991)]. To illustrate how this formalism can shed light on the role of architecture and resonances in determining neuronal output we consider dual recording and reconstruction data from a rat CA1 hippocampal pyramidal cell. Specifically we explore the way in which an $I_{h}$ current contributes to a voltage overshoot at the soma.
Resumo:
This paper describes the process of creating a controlled vocabulary which can be used to systematically analyse the copyright transfer agreements (CTAs) of journal publishers with regard to self-archiving. The analysis formed the basis of the newly created Copyright Knowledge Bank of publishers’ self-archiving policies. Self-archiving terms appearing in publishers’ CTAs were identified and classified, with these then being simplified, merged, and discarded to form a definitive list. The controlled vocabulary consists of three categories that describe ‘what’ can be self-archived, the ‘conditions’ of self-archiving and the ‘restrictions’ of self-archiving. Condition terms include specifications such as ‘where’ an article can be self archived, restriction terms include specifications such as ‘when’ the article can be self archived. Additional information on any of these terms appears in ‘free-text’ fields. Although this controlled vocabulary provides an effective way of analysing CTAs, it will need to be continually reviewed and updated in light of any major new additions to the terms used in publishers’ copyright and self-archiving policies.