Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2017
Abstract
Estimates of stand averages are needed by forest management for planning purposes. In forest enterprise inventories supported by remotely sensed auxiliary data, these estimates are typically derived exclusively from a model that does not consider stand effects in the study variable. Variance estimators for these means may seriously underestimate uncertainty, and confidence intervals may be too narrow when a model used for computing a stand mean omits a nontrivial stand effect in one or more of the model parameters, a nontrivial spatial distance dependent autocorrelation in the model residuals, or both. In simulated sampling from 36 populations with stands of different sizes and differing with respect to (i) the correlation between a study variable (Y) and two auxiliary variables (X), (ii) the magnitude of stand effects in the intercept of a linear population model linking X to Y, and (iii) a first-order autoregression in Y and X, we learned that none of the tested designs provided reliable estimates of the within-stand autocorrelation among model residuals. More-reliable estimates were possible from stand-wide predictions of Y. The anticipated bias in an estimated autoregression parameter had a modest influence on estimates of variance and coverage of nominal 95% confidence intervals for a synthetic stand mean.
Abstract
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Authors
Heidi Udnes Aamot Ingeborg Klingen Simon G. Edwards May Bente Brurberg Guro Brodal Toril Eklo Hege Særvold Steen Jafar Razzaghian Elisa Gauslaa Ingerd Skow HofgaardAbstract
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Authors
Anders Nielsen Bjørn Arild Hatteland Martin Malmstrøm Ted von Proschwitz Gaute Velle Hugo de Boer Jan Ove Gjershaug Lawrence R. Kirkendall Eli Knispel Rueness Vigdis VandvikAbstract
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Authors
Alessio Cibati Bente Føreid Ajay Bissessur Simona HapcaAbstract
In this work, experimental and modelling investigations were conducted on biochars pyrolyzed at 350 °C and 600 °C, to determine the effect of pyrolysis temperature, hydrogen peroxide activation and pH on copper and zinc removal, in comparison with commercially available activated carbons. Characterization of biochars was performed by BET surface area, elemental analysis and FTIR spectroscopy. Experiments results demonstrated that biochar pyrolyzed at 600 °C adsorbed both copper and zinc more efficiently than biochar pyrolyzed at 350 °C. Chemical activation by H2O2 increased the removal capacity of biochar pyrolyzed at 350 °C. All investigated biochars showed a stronger affinity for copper retention, with a maximum adsorption capacity of 15.7 mg/g while zinc was 10.4 mg/g. The best adsorption performances were obtained at pH 5 and 6. Langmuir adsorption isotherm described copper adsorption process satisfactorily, while zinc adsorption was better described by Freundlich isotherm.
Abstract
No abstract has been registered
Abstract
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Authors
Håvard SteinshamnAbstract
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Abstract
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Authors
Rasmus Dam Wollenberg Wagma Saei Klaus Ringsborg Westphal Carina Sloth Klitgaard Kåre Lehmann Nielsen Erik Lysøe Donald Max Gardiner Reinhard Wimmer Teis Esben Sondergaard Jens Laurids SørensenAbstract
Production of chrysogine has been reported from several fungal genera including Penicillium, Aspergillus, and Fusarium. Anthranilic acid and pyruvic acid, which are expected precursors of chrysogine, enhance production of this compound. A possible route for the biosynthesis using these substrates is via a nonribosomal peptide synthetase (NRPS). Through comparative analysis of the NRPSs from genome-sequenced producers of chrysogine we identified a candidate NRPS cluster comprising five additional genes named chry2–6. Deletion of the two-module NRPS (NRPS14 = chry1) abolished chrysogine production in Fusarium graminearum, indicating that the gene cluster is responsible for chrysogine biosynthesis. Overexpression of NRPS14 enhanced chrysogine production, suggesting that the NRPS is the bottleneck in the biosynthetic pathway.