Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2010
Authors
Emmanuel Lapied Claire Coutris Elara Moudilou Jean-Marie Exbrayat Deborah H. Oughton Erik JonerAbstract
No abstract has been registered
Authors
E Lapied Deborah H. Oughton Erik JonerAbstract
In terrestrial ecotoxicology there is a serious lack of data for potential hazards posed by engineered nanoparticles (ENPs). This is partly due to complex interactions between ENPs and the soil matrix, but also to the lack of suitable toxicological endpoints in organisms that are exposed to ENPs in a relevant manner. Earthworms are recognized as key organisms in terrestrial ecosystems, but so far only physiological endpoints of low sensitivity have been used in ecotoxicity studies with ENPs. We exposed the earthworm Lumbricus terrestris to different concentrations (1-100 ppm) silver nanoparticles of two contrasting sizes under three different conditions; in water, in food and in soil. After exposure, we measured the impact on apoptosis in different tissues using two staining techniques to determine apoptosis; TUNEL and Apostain. A dose-dependent response was detected with respect to apoptotic activity in a range of tissues both at acute and sub-lethal concentrations (down to 4 mg kg soil-1). Comparing exposure in water and soil showed that reduced bioavailability in soil is reflected in the apoptotic response. Apoptosis thus seems to be a sensitive endpoint for detection of adverse effects of silver nanoparticles, and potentially a powerful tool for quantifying environmental hazards posed by ENPs.
Abstract
The model FROSTOL simulates course of frost tolerance in winter wheat on a daily basis from sowing on as affected by soil temperature (2 cm), snow cover, phenological development, and a genotypic maximum level of frost tolerance (LT 50). A series of cultivar trials in Finland was used to evaluate the model's ability to estimate plant survival in natural field environments during winters with differing weather conditions. Recorded survival was compared with number of intersections between the curves of simulated LT50 and the soil temperature curve for each field. A cumulative stress level (CSL) was calculated based both on number of intersections and FROSTOL simulated stress levels. The correlation between CSL and field recordings was quite low. While the field trials characterize a general ability to stand various types of winter stress, FROSTOL estimates damage caused by the soil temperature regime only. However, FROSTOL simulations seemed to correspond reasonably well to field observations when low temperature was the eventual cause of damage.
Abstract
No abstract has been registered
Abstract
Timothy (Phleum pratense L) is the most important forage grass in Scandinavia and it is therefore highly interesting to study how it will perform in a changing climate. In order to model winter survival, the dynamics of hardening and dehardening must be simulated with satisfactory precision. We investigated an early timothy frost tolerance model (LT50 model), and an LT50 model for winter wheat. Based on the assumption that timothy has no vernalization requirement, unlike winter wheat, but does have the ability to adapt to cold temperatures in a process linked to stage of development, two alternative versions of the winter wheat model were also constructed. In total, these four candidate models were calibrated by a Bayesian approach for the timothy cultivar Engmo. The candidate models were validated using independent observations on LT50 in timothy at different locations reflecting differences in climate. A sensitivity analysis, using the Morris method, to identify important model parameters suggested that there is a connection between frost tolerance and stage of plant development, even if there is no vernalization requirement. The simplified winter wheat model was selected as the best candidate model for LT50 in timothy based on model selection criteria and its ability to capture the hardening and dehardening processes. The results from the Bayesian calibration suggest that there are no major regional differences in Norway calling for regional calibration. However, cultivar-specific calibration is probably required, since there are hardy and less hardy cultivars within the same species. A functional LT50 model would allow risk assessments to be made of future winter survival using specifically tailored and downscaled climate scenarios. (C) 2010 Elsevier B.V. All rights reserved.
Authors
Geir-Harald StrandAbstract
The change from one landscape to another is gradual. Landscape classes can therefore be considered as theoretical concepts and a particular location or area can be affiliated with a number of different landscape classes. Landscape classification thus becomes a statistical and probabilistic exercise. Such a probabilistic approach to landscape regions can be made operational using a grid model combined with binary logistic regression. This approach was tested on a landscape region in Norway.
Authors
Lone Ross Gobakken Patricia K. LebowAbstract
Mould growth on coated wood is today a genuine challenge for house owners. Environmentally sound wooden facades with long service lives and acceptable appearance are desired. The objective in this study was to investigate the accumulated mould growth on 13 different wood substrates with 3 surface coating systems by identifying the factors that contribute to the variation and to predict future performance. A generalized linear mixed model was fit to the data with the analysis showing that coating and exposure time both had highly significant influences on mould growth. Further, wood substrate was significant, but comparatively less than coating and exposure time. A smaller coefficient for mould coverage in the beginning of the exposure period gave the panels with one of the coating systems, BAP, a delay in mould growth, and the extrapolated values for years 6-12 indicate a longer aesthetic service life than panels with the two other coating systems. Coated heartwood as wood type was less susceptible to mould growth than coated mixed wood and coated sapwood. Acetylated pine as wood substrate and aspen as wood species had lower resistance to mould growth than the other wood substrates and wood species, respectively.
Authors
Karen Refsgaard Thomas G. JohnsonAbstract
No abstract has been registered
Abstract
Studying the winter survival of forage grasses under a changing climate requires models that can simulate the dynamics of soil conditions at low temperatures. We developed a simple model that simulates depth of snow cover, the lower frost boundary of the soil and the freezing of surface puddles. We calibrated the model against independent data from four locations in Norway, capturing climatic variation from south to north (Arctic) and from coastal to inland areas. We parameterized the model by means of Bayesian calibration, and identified the least important model parameters using the sensitivity analysis method of Morris. Verification of the model suggests that the results are reasonable. Because of the simple model structure, some overestimation occurs in snow and frost depth. Both the calibration and the sensitivity analysis suggested that the snow cover module could be simplified with respect to snowmelt and liquid water content. The soil frost module should be kept unchanged, whereas the surface ice module should be changed when more detailed topographical data become available, such as better estimates of the fraction of the land area where puddles may form.
Authors
Bruce Talbot Nils Egil Søvde H. Fridén Lars WilhelmssonAbstract
This paper builds on findings from the recently finalised work package 3.9 of the EU Indisputable Key project. Three institutes cooperated in developing intricate models spanning from the standing tree to the dispatch yard of a Swedish window manufacturer. Numerous timber properties were assigned to RFID tags, applied to the log at felling by a specially adapted harvester head. Logs were allocated to each of seven sawmills according to their timber properties using an LP based optimisation procedure. Simulation was then used to compare the fate of traced timber throughout the production lines of one of the sawmills and its downstream manufacturers.....