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The Multivariate Normal Inverse Gaussian distribution: EM-estimation and analysis of synthetic aperture sonar data
(Journal article; Tidsskriftartikkel; Peer reviewed, 2004-09)
The heavy-tailed Multivariate Normal Inverse Gaussian (MNIG) distribution is a recent variance-mean mixture of a multivariate Gaussian with a univariate inverse Gaussian distribution. Due to the complexity of the likelihood function, parameter estimation by direct maximization is exceedingly difficult. To overcome this problem, we propose a fast and accurate multivariate ExpectationMaximization (EM) ...
"Poèt v Rossii – Bol’she chem Poèt" or the Poet as Superman
(Journal article; Tidsskriftartikkel, 2004)
Rapidly changing life history during invasion
(Journal article; Tidsskriftartikkel; Peer reviewed, 2004-05-17)
The fish species vendace (<i>Coregonus albula</i>) invaded the sub‐arctic Pasvik watercourse during the second half of the 1980s, and became the dominant pelagic species in the upstream part of the watercourse within a few years. Life history traits of the pioneer population of vendace in Pasvik were recorded from 1991–2000. A rapid increase in population density in the upstream part of the watercourse ...
Gill raker morphology and feeding ecology of two sympatric morphs of European whitefish (Coregonus lavaretus)
(Journal article; Tidsskriftartikkel; Peer reviewed, 2004)
Two whitefish morphs have been identified in lakes in northern Norway from a bimodal distribution of gill raker numbers: a sparsely- and a densely-rakered. Habitat choice and feeding ecology of whitefish were studied in five lakes with the two morphs living in sympatry, and in five lakes harbouring only the sparsely-rakered morph. In sympatry, the two whitefish morphs exhibited a strict niche ...
Ecological interactions and evolution: Forgotten parts of biodiversity?
(Journal article; Tidsskriftartikkel; Peer reviewed, 2004-09-01)
<p>Organisms are shaped contemporaneously by ecological processes and over long periods of time by evolution, processes that have led to the diversification of life. But is the diversity of life all biodiversity is? We argue that biodiversity is the conclusion drawn both from the variety of life forms and from the variety of processes that have shaped them. One cannot talk about biodiversity in a ...