Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2019
Forfattere
Kirsten TørresenSammendrag
Det er ikke registrert sammendrag
Sammendrag
A novel method for age-independent site index estimation is demonstrated using repeated single-tree airborne laser scanning (ALS) data. A spruce-dominated study area of 114 km2 in southern Norway was covered by single-tree ALS twice, i.e. in 2008 and 2014. We identified top height trees wall-to-wall, and for each of them we derived based on the two heights and the 6-year period length. We reconstructed past, annual height growth in a field campaign on 31 sample trees, and this showed good correspondence with ALS based heights. We found a considerable increase in site index, i.e. about 5 m in the H40 system, from the old site index values. This increase corresponded to a productivity increase of 62%. This increase appeared to mainly represent a real temporal trend caused by changing growing conditions. In addition, the increase could partly result from underestimation in old site index values. The method has the advantages of not requiring tree-age data, of representing current growing conditions, and as well that it is a cost-effective method with wall-towall coverage. In slow-growing forests and short time periods, the method is least reliable due to possible systematic differences in canopy penetration between repeated ALS scans.
Sammendrag
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Forfattere
Åge Arild NyborgSammendrag
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Sammendrag
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Sammendrag
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Forfattere
Di Zeng Michael R. Thomsen Rodolfo M. Jr. Nayga Judy L. BennettSammendrag
Retail food environment is increasingly considered in relation to obesity. This study investigates the impacts of access to supermarkets, the primary source of healthy foods in the United States, on the bodyweight of children. Empirical analysis uses individual-level panel data covering health screenings of public schoolchildren from Arkansas with annual georeferenced business lists, and utilizes the variations of supermarket openings and closings. There is little overall impact in either case. However, supermarket openings are found to reduce the BMI z-scores of low-income children by 0.090 to 0.096 standard deviations. Such impact remains in a variety of robustness exercises. Therefore, improvement in healthy food access could at least help reduce childhood obesity rates among certain population groups.
Forfattere
Klaus MittenzweiSammendrag
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Forfattere
Klaus Ringsborg Westphal Katrine Amalie Hamborg Nielsen Rasmus Dam Wollenberg Mathias Bonde Møllehøj Simone Bachleitner Lena Studt Erik Lysøe Henriette Giese Reinhard Wimmer Jens Laurids Sørensen Teis Esben SondergaardSammendrag
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Forfattere
Olav Aaseth Hegnar Barry Goodell Claus Felby Lars Johansson Nicolé Labbe Keonhee Kim Vincent Eijsink Gry Alfredsen Aniko VarnaiSammendrag
The recalcitrance bottleneck of lignocellulosic materials presents a major challenge for biorefineries, including second-generation biofuel production. Because of their abundance in the northern hemisphere, softwoods, such as Norway spruce, are of major interest as a potential feedstock for biorefineries. In nature, softwoods are primarily degraded by basidiomycetous fungi causing brown rot. These fungi employ a non-enzymatic oxidative system to depolymerize wood cell wall components prior to depolymerization by a limited set of hydrolytic and oxidative enzymes. Here, it is shown that Norway spruce pretreated with two species of brown-rot fungi yielded more than 250% increase in glucose release when treated with a commercial enzyme cocktail and that there is a good correlation between mass loss and the degree of digestibility. A series of experiments was performed aimed at mimicking the brown-rot pretreatment, using a modified version of the Fenton reaction. A small increase in digestibility after pretreatment was shown where the aim was to generate reactive oxygen species within the wood cell wall matrix. Further experiments were performed to assess the possibility of performing pretreatment and saccharification in a single system, and the results indicated the need for a complete separation of oxidative pretreatment and saccharification. A more severe pretreatment was also completed, which interestingly did not yield a more digestible material. It was concluded that a biomimicking approach to pretreatment of softwoods using brown-rot fungal mechanisms is possible, but that there are additional factors of the system that need to be known and optimized before serious advances can be made to compete with already existing pretreatment methods.