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.
2004
Sammendrag
The sun is an abundant energy source, and increasing efforts are made to find more efficient ways to exploit it, than commonly used today. Hydrogen is considered to be the energy carrier of the future, and the potential for a sustainable system where hydrogen is obtained directly from solar energy, has been studied extensively. One alternative is the process of biophotolysis. Sulfur starvation of the green algae Chlamydomonas reinhardtii is known to cause hydrogen production under illumination, by biophotolysis where solar energy is used to produce significant amounts of hydrogen involving parts of the photosynthetic process. So far, little is known about this process in other species, and in this work we have investigated different species of green algae with respect to hydrogen production under sulfur starvation. A number of algae cultures were screened with respect to physiological response to sulfur deprivation in small-scale laboratory cultures under controlled conditions. Test parameters included hydrogen production, reduction of oxygen production, changes in morphology and other aspects of physiology. Investigations of oxygen sensitivity of hydrogenases were also performed. It was shown that other species than C. reinhardtii are able to produce hydrogen under sulfur deprivation.
Sammendrag
Most energy carriers that are in common use today originate from solar energy. Hydrogen is considered to be the energy carrier of the future, and the potential for a sustainable system where hydrogen is obtained directly from solar energy, has been studied by several researchers over the years. Several groups of microorganisms have shown the ability to produce hydrogen by natural biological processes using solar energy. Efforts have been made to understand the mechanisms involved in photobiological hydrogen production from these organisms, and to optimise the process. This work has recently resulted in a significant breakthrough. It has been discovered that some species of green algae have the ability to produce significant amounts of hydrogen during sulphur starvation, which allows hydrogen to be produced in light. However, very little is known about how this process varies between species. We have chosen to investigate green algae, with the intention to examine a variety of species for hydrogen production during sulphur starvation. A number of algae cultures were screened with respect to physiological response to sulphur deprivation in small-scale laboratory cultures under controlled conditions. Results from both marine and fresh water algae will be presented.
Forfattere
Ole Martin Eklo Jens Kværner Eivind Solbakken Ivar Solberg Stein SorknesSammendrag
Det er ikke registrert sammendrag
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Det er ikke registrert sammendrag
Forfattere
Eivind VangdalSammendrag
Under omsetninga av plommer er svinnet vurdert til kring 20%. Dette er frukt som ikkje vert seld fordi ho er overmogen, rotna eller fysiske skader. Men i tillegg letnar frukta frå ho vert hausta og fram til forbrukaren. Dette vekttapet skuldast m.a. forbrenning av sukker i andingsprosessane og direkte fordamping. Tapet kan reduserast med god kjøling, modifisert atmosfære pakningar og god luftråme. Plommesortane Souffriau og Reeves har lite vekttap etter hausting. Avalon er mellom sortane som letnar mykje. Vekttapet for Avalon er tre gonger så stort som for Reeves.
Sammendrag
This study presents empirical insight into organic and conventional cash crop farmers" perceptions of risk and risk management strategies, and identifies socio-economic variables linked to these perceptions. The data originate from a questionnaire survey of farmers in Norway. The results indicate that organic farmers perceived themselves to be less risk averse than conventional farmers. For both groups, crop prices and yield variability were the two top rated sources of risk, followed by institutional risks. The two groups evaluated risk management strategies quite similarly; favoured strategies were good liquidity and to prevent and reduce crop diseases and pests. The farmers" evaluation of sources of risk and choice of risk strategies depended on various socio-economic variables. The importance of institutional risks implies that policy makers should be cautious about changing policy capriciously and they should consider strategic policy initiatives that give farmers more long-term reliability.
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Det er ikke registrert sammendrag
Forfattere
Reidun PommerescheSammendrag
Surface-active spiders were sampled from a ley and two adjacent field margins on a dairy farm in western Norway, using pitfall traps from April to June 2001. Altogether, 1153 specimens, representing 33 species, were found. In total, 10 species were found in the ley, 16 species in the edge of the ley, 22 species in the field margin "ley/forest" and 16 species in the field margin "ley/stream". Erigone atra, Bathyphantes gracilis, Savignia frontata and Collinsia inerrans were the most abundant species in the ley. C. inerrans was not found in the field margins. This species is previously recorded only a few times in Norway. Diplocephalus latifrons, Tapinocyba insecta, Dicymbium tibiale, Bathyphantes nigrinus and Diplostyla concolor were most abundant in the field margin "ley/ forest". D. latifrons, D. tibiale and Pardosa amentata were most abundant in the field margin "ley/ stream", followed by E. atra and B. gracilis. The present results were compared to results from ley and pasture on another farm in the region, recorded in 2000. A Detrended Correspondence Analyses (DCA) of the data sets showed that the spider fauna from the leys were more similar, independent of location, than the fauna in ley and field margins on the same locality. The interactions between cultivated fields and field margins according to spider species composition, dominance pattern and habitat preferences are discussed.
Forfattere
Annette Folkedal Schjøll Christian BrevigSammendrag
In Norway, a web-based warning system called VIPS has been developed under a national government funded programme for reduced risk of pesticides used in agriculture. VIPS is a collaboration project between the Norwegian Crop Research Institute, Plant Protection Centre and the Norwegian Agricultural Extension Service. The aim of VIPS is to give open access to all the information needed for farmers to reduce their reliance on pesticides. VIPS calculates warnings for more than 70 weather stations for several pests and diseases in selected fruits, vegetables and cereals. Registered users may adjust the climatic data used in the models and register field observations to get private warnings and use the system to record farm-practices. VIPS is unique in several aspects: " A general user-interface for all crops and all pests and diseases; the user gets a quick overview of which pests to look out for. " Warnings are site specific and linked to an authorized weather station which supplies validated meteorological data. The extension service supplies the validated biological data necessary to run the models. " The presentation is layered under the weather stations of each county. First level gives information of danger (red), possible danger (yellow) and no danger (green) for each model (past five days/coming five days). The next 3 levels give information of the specific model, historical data and exact values of the input parameters used in the models for the calculations.