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.
2011
Forfattere
Lone Ross Gobakken Olav Albert HøibøSammendrag
Mould growth on exterior coated cladding façades is an undesirable element and will often shorten the aesthetical service life. Mould growth on painted surfaces is influenced by type and concentration of film fungicides, the paint formulation and the wood substrate itself, and wooden cladding may experience exponential fungal deterioration caused by variation in the climatic factors, often within a small limited area. The objective of this study was to gain knowledge about which factors influence surface mould growth on coated and uncoated wooden cladding in an outdoor environment, with a special attention to modified wood substrates. The data are based on evaluation of mould growth coverage on outdoors exposed wood panels consisting of different combinations of wood substrates and surface finishes. Panels were exposed on three locations; Bogesund (Sweden), Birkenes and Sørkedalen (Norway). The panels were monitored up to 4.5 years. The analysis showed that coating typology and exposure time both had highly significant influences on mould growth. Furthermore, wood substrate, temperature and relative humidity had a significant influence on mould growth, but comparatively less than coating typology and exposure time. Siberian larch heartwood, copper-organic preserved Scots pine and Scots pine heartwood performed best among the wood substrates. Heartwood as wood type was less susceptible to mould growth than a mix of sapwood and heartwood wood and pure sapwood. Acetylated Scots pine as wood substrate and Aspen as wood species had lower resistance to mould growth than the other wood substrates and wood species, respectively. The physical surface structure of a paint film also influences the mould growth. A hard model paint was significantly more susceptible than the other model paints. A soft model paint performed best, with the least mould growth coverage. Aureobasidium pullulans (deBary) Arnaud was the dominating fungal species on all the wood substrates.
Forfattere
Marte Haave Annette Bernhard Finn K. Jellestad Einar Heegaard Trond Brattelid Anne-Katrine LundebyeSammendrag
Background: Polychlorinated biphenyls (PCBs) are widespread in the environment, human food and breast milk. Seafood is known to contain nutrients beneficial for the normal development and function of the brain, but also contaminants such as PCBs which are neurotoxic. Exposure to non-coplanar PCBs during brain development can disrupt spontaneous behaviour in mice and lead to hyperactive behaviour. Humans are chronically exposed to the highest relative levels of organochlorines in early childhood during brain development, though usually at doses which do not give clinical symptoms of toxicity. This study aimed to elucidate the developmental and behavioural effects of 2,2’,4,4’,5,5’ hexachlorobiphenyl (PCB153) in mice, mimicking human exposure during gestation and lactation. Methods: Environmentally relevant doses of PCB153 were added to the experimental diets. Feed concentrations were approximately 0.5, 6.5, and 1500 μg PCB153/kg feed, representing a realistic and a worst case scenario of frequent consumption of contaminated fish. The study also investigated the effects of maternal nutrition, i.e. a standard rodent diet versus a high inclusion of salmon. Mice pups were examined for physical- and reflex development, sensorimotor function and spontaneous behaviour from five days after birth until weaning. A selection of pups were followed until 16 weeks of age and tested for open field behaviour and the acoustic startle response (ASR) with prepulse inhibition (PPI). Blood thyroid hormones and liver enzymes, blood lipids and PCB153 content in fat were examined at 16 weeks. Statistical analyses modelled the three way interactions of diet, PCB exposure and litter size on behaviour, using generalized linear models (GLM) and linear mixed effect models (LME). The litter was used as a random variable. Non-parametric tests were used for pair wise comparisons of biochemical analyses. Results: Litter size consistently influenced pup development and behaviour. Few lasting PCB153 related changes were observed, but results indicated effects on synchronization of physical development. Perinatal PCB153 exposure appeared to reduce habituation and cause aggression in males, though not statistically significant. Conclusions: Litter size and maternal diet influenced physical development and function more than PCB153 in perinatally exposed mouse pups and supports the developmental importance of maternal care and the social environment.
Forfattere
Håvard Kauserud Einar Heegaard Rune Halvorsen Lynne Boddy Klaus Høiland Nils Chr. StensethSammendrag
Most basidiomycete fungi produce annual short-lived sexual fruit bodies from which billions of microscopic spores are spread into the air during a short time period. However, little is known about the selective forces that have resulted in some species fruiting early and others later in the fruiting season. This study of relationships between morphological and ecological characteristics, climate factors and time of fruiting are based upon thorough statistical analyses of 66 520 mapped records from Norway, representing 271 species of autumnal fruiting mushroom species. We found a strong relationship between spore size and time of fruiting; on average, a doubling of spore size (volume) corresponded to 3 days earlier fruiting. Small-spored species dominate in the oceanic parts of Norway, whereas large-spored species are typical of more continental parts. In separate analyses, significant relationships were observed between spore size and climate factors. We hypothesize that these relationships are owing to water balance optimization, driven by water storage in spores as a critical factor for successful germination of primary mycelia in the drier micro-environments found earlier in the fruiting season and/or in continental climates.
Forfattere
Igor A. Yakovlev Ari M. Hietala Pierre-Emmanuel Courty Taina Lundell Jan Stenlid Halvor Solheim Carl Gunnar FossdalSammendrag
In forest soils, saprotrophic, necrotrophic and ectomycorrhizal fungi are involved in carbon cycling. Heterobasidion annosum, white rot necrotrophic fungi, is known to decompose wood lignocellulose by secreting a broad range of oxidative enzymes. The genome H. annosum s.l. was sequenced by JGI to a 8.23X coverage and assembled into 39 scaffolds with a total size of 33.7 Mb covering more than 98% of the whole genome. Based on the genome sequence we have characterized gene families coding for enzymes known to participate in conversion of wood lignin: multicopper oxidases (MCOs, 18 genes) as laccases (Lcc), class II peroxidases (8 genes) as manganese peroxidases (MnP), glyoxal oxidases (5 genes, GLOX), quinone-reducing oxidoreductases (19 genes, QOR) and GMC oxidoreductases (12 genes) as aryl alcohol oxidases (AAO). We studied the genomic organisation and phylogeny of these genes as well as their expression using qRT-PCR. Comparative and phylogenetic analyses of genes coding for enzymes involved in wood lignin conversion and decomposition (i.e. lignin-modifying class II peroxidases) reveal differences between white- and brown-rot, necrotrophic and saprotrophic wood-decaying basidiomycetes. Transcript profiling using qRT-PCR revealed that some transcripts were very abundant in lignin-rich media, in cellulose-rich media, in wood or in the free-living mycelium grown liquid culture, suggesting specific functions of these genes, which need to be studied further.
Sammendrag
Remote sensing of the activity of vegetation in relation to environmental conditions provides an invaluable basis for investigating the spatiotemporal dynamics and patterns of variability for ecosystem processes. We investigate the fraction of Absorbed Photosynthetically Active Radiation (fAPAR) using SeaWiFS satellite observations from 1998 to 2005 and ancillary meteorological variables from the CRU-PIK dataset with a global coverage at a spatial resolution of 0.5o x 0.5o. A pixel-by-pixel spectral decomposition using Singular System Analysis leads to a global “classification” of the terrestrial biosphere according to prevalent time-scale dependent dynamics of fAPAR and its relation to meteorology. A complexity analysis and a combined subsignal extraction and dimensionality reduction reveals a series of dominant geographical gradients, separately for different time scales. At the annual scale, which explains around 50% of the fAPAR variability as a global average, patterns largely resemble the biomes of the world as mapped by biogeographical methods, and are driven by temperature and by pronounced rain seasons in the tropics. On shorter time scales, fAPAR fluctuations are exclusively driven by water supply, inducing, e.g., semiannual cycles in the equatorial belt of Africa or the Indo-Gangetic Plain. For some regions however, in particular South America, altitude, mean temperature, drought probability and fire occurrences are parameters that seem to shape the spatial patterns of fAPAR across time scales. Overall, we provide a first global multiscale characterization of fAPAR and highlight different mechanisms in land-surface-climate couplings.
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Merete Wiken Dees Arild Sletten Ricardo Holgado Eldrid Lein Molteberg Tor J. Johansen May Bente Brurberg Vinh Hong Le Ragnhild Nærstad Arne HermansenSammendrag
Det er ikke registrert sammendrag
Forfattere
K. Sawa L. Hejduk Johannes DeelstraSammendrag
Det er ikke registrert sammendrag
Sammendrag
The effect of different light environments on trap catches of Frankliniella occidentalis and Trialeurodes vaporariorum was investigated in a commercial greenhouse rose production unit during late autumn. Two top light treatments were used: 1) High pressure sodium lamps (HPSLs) and 2) HPSLs and light emitting diodes (LEDs) with 20% blue and 80% red light. More thrips and fewer whiteflies were caught on yellow sticky traps, and more thrips were found in the flowers, in areas were LEDs were used in addition to HPSLs compared to areas where only HPSLs were used. No effect of the light treatments was found on the population level of Amblyseius swirskii, but a lower ratio of predatory mites to thrips was found on the plants where LEDs were used. The results suggest that using blue and red LEDs as interlighting, or otherwise supplementary to HPSLs, will change thrips and whitefly spatial distribution in the rose crop, and that natural enemy release rates probably need to be adjusted accordingly.
Forfattere
Lars Sekse U. Wermund R. Vidrih M. Simcic Eivind VangdalSammendrag
Det er ikke registrert sammendrag