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| Elvarsson, B. P.; Taylor, L.; Trenkel, Verena; Kupca, V.; Stefansson, G.. |
| Statistical models of marine ecosystems use a variety of data sources to estimate parameters using composite or weighted likelihood functions with associated weighting issues and questions on how to obtain variance estimates. Regardless of the method used to obtain point estimates, a method is required for variance estimation. A bootstrap technique is introduced for the evaluation of uncertainty in such models, taking into account inherent spatial and temporal correlations in the datasets, which are commonly transferred as assumptions from a likelihood estimation procedure into Hessian-based variance estimation procedures. The technique is demonstrated on a real dataset and the effects of the number of bootstrap samples on estimation bias and variance... |
| Tipo: Text |
Palavras-chave: Bootstrapping; Correlated data; Fish population dynamics; Non-linear models. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00193/30459/29913.pdf |
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| Luten, J.; Bouquet, W.; Oehlenschläger, J.; Meetschen, U.; Etienne, M.; Stroud, G.; Bykowski, P.; Batista, I.; Vyncke, W.; Stefansson, G.. |
| Eight WEFTA laboratories participated in two series of intercomparison exercises on sulfite determination in tropical shrimps. Samples of tropical shrimps were spiked with sodium metabisulfite (Na<sub>2</sub>S<sub>2</sub>O<sub>5</sub>) and hydroxymethylsulfonate (HMS) at a level of 25-90 mg SO<sub>2</sub>/kg. Most of the laboratories determined the sulfite content with (modified) methods of Monier-Williams or De Vries et al. The overall mean recovery of sulfite was rather low (47-60%), which may be attributed to an irreversible reaction of sulfite with the tropical shrimps. The repeatability of the methods within the participating laboratories was good. However, reproducibility among the laboratories was... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Detection; Fishery products; Food technology; International cooperation; Quality control; Recovery; Shrimp fisheries; Sulphites. |
| Ano: 1997 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=5742 |
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