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.
2007
Forfattere
Peder GjerdrumSammendrag
Predicting sawn timber yield continues to be a challenging task, influenced by several stochastic processes. In this paper, a simulation model for main yield and sideboards in softwood sawing is presented. Predicting sawn timber yield usually involves either straight and notional mathematics, or empiric figures, both with inherent drawbacks. Most geometric models fail to take into consideration random variation: in log position when entering the saw, no log being perfectly straight, smooth and circular, sawing accuracy, etc., and therefore systematically overestimate the yield, in particular the sideboards...
Sammendrag
Host tree terpenes can influence attraction of conifer-infesting bark beetles to their aggregation pheromones, and both synergistic and inhibitory effects have been reported. We tested a gradient of ratios of (–)-α-pinene, the predominant monoterpene in Norway spruce, to the pheromone of Ips typographus, a major pest of Norway spruce. Attraction of I. typographus increased as the release rate of (–)-α-pinene increased. The two highest (–)-α-pinene : pheromone ratios (526 : 1 and 2595 : 1) attracted twice as many I. typographus as pheromone alone, whereas low to intermediate ratios (56 : 1, 274 : 1) did not differ from pheromone alone. Our results are in agreement with a proposed model, which suggests that bark beetles display unique response profiles to host terpenes depending on the physiological condition of the host trees that they typically colonize. Ips typographus, which is an aggressive species capable of colonizing and killing healthy trees, showed an increased attraction to monoterpene : pheromone ratios, and this may be high enough to inhibit attraction of less aggressive beetle species typically colonizing dead, dying or stressed trees. Attraction of associates of I. typographus was also modified by (–)-α-pinene. Ips duplicatus, a competitor of I. typographus, showed increased attraction to the pheromone of I. typographus across all concentrations of (–)-α-pinene.
Forfattere
Patrik Flisberg Bertil Lidén Mikael RönnqvistSammendrag
In this paper, we consider an operational routing problem to decide the daily routes of logging trucks in forestry. The industrial problem is difficult and includes aspects such as pickup and delivery with split pickups, multiple products, time windows, several time periods, multiple depots, driver changes and a heterogeneous truck fleet. In addition, the problem size is large and the solution time limited. We describe a two-phase solution approach which transforms the problem into a vehicle routing problem with time windows. In the first phase, we solve an LP problem in order to find a destination of flow from supply points to demand points. Based on this solution, we create transport nodes each of which defines the origin(s) and destination for a full truckload. In phase two, we make use of a standard tabu search method to combine these transport nodes, which can be considered to be customers in vehicle routing problems, into actual routes. The standard tabu search method is extended to consider some new features. The solution approach is implemented as part of a newly developed decision support system and we report on tests made on a set of industrial cases from major forest companies in Sweden.
Forfattere
Michael G. Angstreich Moses M. ZinnahSammendrag
This paper constitutes a formative look at how local knowledge and western science, both social and natural, might be integrated for the benefit of smallholder agriculture in developing countries. The question addressed is: How can research and extension be more responsive to the needs of local farmers and what are some possible elements of a responsive approach? A comparison of local knowledge and western science is given. Constructivist, experiential learning approaches such as Participatory Technology Development (PTD), Participatory Rural Appraisal (PRA), Farmer Field School (FFS) and Promoting Farmer Innovation (PFI) that use the farm as a learning system and farmer-driven on-farm trials are among the qualitative and quantitative methodologies that can contribute to the knowledge and needs of researchers, extensionists and farmers. Using case studies from East and West Africa and a review of the literature, this paper addresses issues related to strengthening effective linkages between farmers, extension professionals and researchers.
Forfattere
Espen Govasmark Mark G. GrimmettSammendrag
An existing laboratory procedure for selenium analysis using open-vessel wet digestion and liquid chromatographic fluorescence determination was modified for use with microwave digestion. The proposed microwave digestion method eliminated the hazards associated with the use of HCIO4 while maintaining excellent recoveries of selenium. A 2-step HNO3/H2O2 digestion procedure was developed. Digested samples were derivatized with 2,3-diaminonaphthalene, and the resultant piazselenol complex was measured fluorometrically using a liquid chromatograph. Measured values were in agreement with 9 different certified reference materials. The detection limit for this method was 0.54 ng Se/g tissue (3 s), and the calibration curve remained linear (r2 = 0.9968) up to 2 mg Se/g.
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
River floods may cause considerable damage. Water management strategies intend tomoderate or mitigate the severe effects of extreme discharge events. In this context,techniques for the detection and attribution of changes is of crucial importance. Extremeflood events seem to occur more frequently in recent decades in central Europe.It is anticipated that climate change and weather regime shifts may contribute to this...
Forfattere
Svein Ole BorgenSammendrag
Det er ikke registrert sammendrag
Forfattere
Arnstein Staverløkk May-Guri Saethre Eline Benestad HågvarSammendrag
The invasive ladybird, Harmonia axyridis Pallas 1773, is recorded for the first time in Norway. The specimen was found on horticultural plants imported from Aalsmeer in the Netherlands to Oslo, Norway. H. axyridis originates from East-Asia. The species is known to be a voracious predator on aphids and has been extensively used as a biological control agent in both North America and Europe. The later years, however, a number of negative impacts on the environment and biodiversity have been reported. The species was assessed as a potential bio-control agent for use in Norwegian greenhouses in 2001. The outcome of the assessment was negative with respect to import and commercial use in Norway. It was concluded that H. axyridis might survive and become established outdoors and thereby pose a risk to the environment. Recent experiences from the UK have shown that H. axyridis compasses several of the traits characterizing a successful invasive alien species. The record of this species in Norway may only be the first in a number of such, as it is likely that this species will survive outdoors, at least in the southern parts of Norway.
Forfattere
Arnstein Staverløkk May-Guri Sæthre Eline HågvarSammendrag
Det er ikke registrert sammendrag