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.
2002
Sammendrag
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Sammendrag
Patrolling with livestock guard dogs in mountain rangelands in Norway was evaluated as a method to prevent predation in areas with widely dispersed sheep. In contrast to the traditional use of guard dogs, patrol dogs are closer socially bonded to people and follow a range inspector around. Range inspection was performed in 5 h bouts during three nights per week. The method was tested during three summer seasons in a total of eight sheep flocks grazing in three different mountain ranges. In total, three inspectors and four dogs were involved. Significant reductions in the number of sheep lost were achieved in one of the study areas. Lack of significance in the other areas were mainly due to the size of the area and qualities of the dogs: the range to be patrolled by one man/dog unit should not exceeed 10-12 km2, and the dogs should be experienced guard dogs, which are properly socialized for this method.
Sammendrag
Norwegian fluid milk consumption has declined steadily over the last twenty years, despite the dairy industry spending increasing amounts of money on advertising. Using a two-stage model, we investigate whether advertising has increased the demand for milk. No effect of advertising on the demand for non-alcoholic beverages is found in the first stage. In the second stage, an almost ideal demand system including advertising expenditures on competing beverages is estimated. The effects of generic advertising within the beverage group are positive and significant for whole milk and negative and significant for lower fat milk. The own-advertising elasticity for the combined fluid milk group is 0.0008. This highly inelastic elasticity suggests that increased advertising will not be profitable for the producers. Several cross-advertising effects are statistically significant, emphasizing the usefulness of a demand system approach.
Forfattere
Per K. Egeberg Alfred A. Christy Morten EikenesSammendrag
The objectives of this work are; 1) to determine the diffuison coefficients of NOM by diffusivimetry. 2) to compare the results with diffusion coefficients determined by two other methods (fluorescence correlation spectroscopy (FCS) and dynamic adsorption experiments (DAM). 3) to compare molecular weights derived from the diffusion coefficients to molecular weights determined by three different ultra filtration experiments and High Perfomance Size Exclusion Chromatography (HPSEC). The diffusion coefficients determined in this work (stirred diffusion cell) are about 70% higher than determined by DAM, and agree well with diffusion coefficients determined by FCS. Molecular weights determined by HPSEC are of the same magnitude as molecular weights derived from diffusion coefficients. Molecular weights determined by ultra filtration vary considerably depending on the choice of membrane types. Membranes made of cellulose acetate generate results similar to results derived from diffusion coefficients. Membranes made of regenerated cellulose and polyether sulfone appear to retain too much NOM, resulting in artificially high molecular weights.
Sammendrag
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Forfattere
Anne Kjersti Bakken Åsmund Asdal Trygve Aamlid Tor Arvid Breland Trond Knapp Haraldsen Tore SveistrupSammendrag
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Sammendrag
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Sammendrag
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Sammendrag
Cleaning of containers to counteract infection that might cause root dieback should remove old, adhering media and roots that may harbour pathogens. This study investigated seedling growth and the number of viable fungal propagules retained on the container cavity walls as a result of different container cleaning treatments: washing with cold water (ca 8C) only, or in addition with a bath temperature of 60, 70, 80 or 95C for 30 seconds.More fungal propagules were isolated from containers washed in cold water, than from the other treatments. The most frequently isolated fungi were Paecilomyces sp. and Penicillium sp., which are well known saprophytes. Bacteria and yeast did not seem to be affected by the washing.Electron microscopy studies of container cavity walls revealed many organic particles and fungal spores on the walls of coldwashed containers. Among other fungal spores there were visible chains of Paecilomyces spp. spores.Containers that were washed at 80C had some organic debris attached to the cavity walls, but no spores were visible. In used and unwashed containers fungal spores, hyphae and organic debris were found on the container cavity walls. Containers in which the major part of the seedlings previously had suffered from root dieback might have contained a considerable amount of inoculum before washing.Almost 60% of the seedlings grown in unwashed containers had dead or very stunted root systems, whereas about 10% of the seedlings in cold washed containers suffered from severe root dieback. Additional warm water treatment further reduced the root dieback of this group of containers. In unwashed containers in which healthy seedlings had been grown, about 4% seedlings and after cold washing no seedlings with root dieback were observed.The cold washing procedure had a positive effect on seedling height, but there was no additional effect of the warm water treatment. We conclude that cold pressurised washing alone does not provide adequate control of root dieback and that an additional warm water bath of at least 60C is recommended.
Sammendrag
The purpose of this study was to test the activity of gibberellins and auxins for induction of parthenocarpic fruit development in cloudberry, Rubus chamaemorus L., a dioecious, northern wild berry with potential for cultivation. Plant hormones were applied directly to open flowers, either dissolved in ethanol or as an aqueous spray. Of the tested gibberellins (GA1, GA3, GA4, dimethyl-GA4, GA5, GA9, GA19, GA20 and GA24) only GA1, GA3, GA4 and dimethyl-GA4 were active and induced fruit development comparable to development of pollinated fruits. Lack of activity of GA20 and GA9, the immediate precursors of GA1 and GA4, respectively, suggests that 3 b-hydroxylation of gibberellins can be inhibited in unpollinated flowers of cloudberry. Auxin treatments induced an initial fruit development, but did not result in ripe berries. Based on these results, use of transgenic methods to regulate gibberellin or/and auxin biosynthesis in carpels of cloudberry could be used to develop a parthenocarpic cloudberry.