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.
2017
Sammendrag
We conducted a series of diagnostic fitness response experiments on the coccolithophore, Emiliania huxleyi, isolated from the Subtropical Convergence east of New Zealand. Dose response curves (i.e., physiological rate vs. environmental driver) were constructed for growth, photosynthetic, and calcification rates of E. huxleyi relative to each of five environmental drivers (nitrate concentration, phosphate concentration, irradiance, temperature, and pCO2). The relative importance of each environmental driver on E. huxleyi rate processes was then ranked using a semi-quantitative approach by comparing the percentage change caused by each environmental driver on the measured physiological metrics under the projected conditions for the year 2100, relative to those for the present day, in the Subtropical Convergence. The results reveal that the projected future decrease in nitrate concentration (33%) played the most important role in controlling the growth, photosynthetic and calcification rates of E. huxleyi, whereas raising pCO2 to 75 Pa (750 ppm) decreased the calcification : photosynthesis ratios to the greatest degree. These findings reveal that other environmental drivers may be equally or more influential than CO2 in regulating the physiological responses of E. huxleyi, and provide new diagnostic information to better understand how this ecologically important species will respond to the projected future changes to multiple environmental drivers.
Forfattere
Monica Suarez Korsnes Reinert KorsnesSammendrag
The marine toxin yessotoxin (YTX) can cause various cytotoxic effects depending on cell type and cell line. It is well known to trigger distinct mechanisms for programmed cell death which may overlap or cross-talk. The present contribution provides the first evidence that YTX can cause genotoxicity and induce mitotic catastrophe which can lead to different types of cell death. This work also demonstrates potential information gain from non-intrusive computer-based tracking of many individual cells during long time. Treatment of BC3H1 cells at their exponential growth phase causes atypical nuclear alterations and formation of giant cells with multiple nuclei. These are the most prominent morphological features of mitotic catastrophe. Giant cells undergo slow cell death in a necrosis-like manner. However, apoptotic-like cell death is also observed in these cells. Electron microscopy of treated BC3H1 cells reveal uncondensed chromatin and cells with double nuclei. Activation of p-p53, p-H2AX, p-Chk1, p-ATM, and p-ATR and down-regulation of p-Chk2 indicate DNA damage response and cell cycle deregulation. Micronuclei formation further support this evidence. Data from tracking single cells reveal that YTX treatment suppresses a second round of cell division in BC3H1 cells. These findings suggest that YTX can induce genomic alterations or imperfections in chromosomal segregation leading to permanent mitotic failure. This understanding extends the list of effects from YTX and which are of interest to control cancer and tumor progression.
Forfattere
Sølvi Wehn Katrina RønningenSammendrag
Semi-natural habitats are key habitats for biodiversity in agricultural landscapes, but are threatened due to structural change and decline in agriculture. In Norway, the Action Plan for Hay Meadows (APHM) was implemented in 2009, including management agreements with farmers/land owners/users. In this study the results and experiences in two study areas in Møre og Romsdal regional county, South-Western Norway, was carried out with the aim to assess crucial aspects of the APHM. This interdisciplinary study was based on a combination of botanical studies of hay meadows of 14 properties holding landscape management agreements and a social science approach with qualitative, semi-structured interviews, aiming at societal aspects influencing the management of these biologically and culturally important hay meadows. One aim was to investigate whether Traditional Ecological Knowledge (TEK) could be utilised in order to optimalise hay meadow management. By investigating the relationship between the proportion mature plants of the semi-natural grassland specialists and the phenology of earlier identified TEK indicators, we could not define one valid TEK-point based on the species used to indicate when to start mowing historically. However, we found that variations in time of hay cut, rather than a rigid date, is crucial. Interviews showed that little remained of what may be defined as TEK. Owners/users in general appreciated the scheme, and had in general few problems adapting to scheme prescriptions. Without the scheme, many of the meadows would not have been properly managed. However, owners/users were concerned regarding issues of fertilizing and impoverishment of the soil, which may be linked to upheaval of the previously common grazing in spring and/or autumn. Overall, the scheme may be described as a success, however, a serious concern is the high average age of owners/users, lack of successors to the farms and properties for future management of these hay meadows.
Sammendrag
Main conclusion: Epigenetic memory affects the timing of bud burst phenology and the expression of bud burstrelated genes in genetically identical Norway spruce epitypes in a manner usually associated with ecotypes. In Norway spruce, a temperature-dependent epigenetic memory established during embryogenesis affects the timing of bud burst and bud set in a reproducible and predictable manner. We hypothesize that the clinal variation in these phenological traits, which is associated with adaptation to growth under frost-free conditions, has an epigenetic component. In Norway spruce, dehydrins (DHNs) have been associated with extreme frost tolerance. DHN transcript levels decrease gradually prior to flushing, a time when trees are highly sensitive to frost. Furthermore, EARLY BUD BREAK 1 genes (EBB1) and the FT-TFL1- LIKE 2-gene (PaFTL2) were previously suggested to be implied in control of bud phenology. Here we report an analysis of transcript levels of 12 DHNs, 3 EBB1 genes and FTL2 in epitypes of the same genotype generated at different epitype-inducing temperatures, before and during spring bud burst. Earlier flushing of epitypes originating from embryos developed at 18 C as compared to 28 C, was associated with differential expression of these genes between epitypes and between buds and last year’s needles. The majority of these genes showed significantly different expressions between epitypes in at least one time point. The general trend in DHN expression pattern in buds showed the expected reduction in transcript levels when approaching flushing, whereas, surprisingly, transcript levels peaked later in needles, mainly at the moment of bud burst. Collectively, our results demonstrate that the epigenetic memory of temperature during embryogenesis affects bud burst phenology and expression of the bud burst-related DHN, EBB1 and FTL2 genes in genetically identical Norway spruce epitypes.
Forfattere
José Ramón González-Olabarria Jordi Garcia-Gonzalo Blas Mola-Yudego Timo PukkalaSammendrag
& Key message We generate flexible management rules for black pine stands, adaptable to alternative stand management situations and entailing thinnings, final-felling, and salvage cuts, based on the results on 270 stand level optimizations. & Context Forest management instructions often rely on the anticipated prediction of the stand development, which poses a challenge on variable economic and environmental conditions. Instead, an alternative approach to better adapt forest management decisions to changing conditions is defining flexible rules based on thresholds that trigger management operations. & Aims This article develops rules for the adaptive management of P. nigra stands in Catalonia (Spain) addressing the risk of fire and post-fire forest management. & Methods The stochastic version of the simulationoptimization system RODAL was used to optimize the management of forest stands in three sites under different fire probability levels. A total of 270 optimizations were done varying site fertility, fire probability, and economic factors. The results of the optimizations were used as the basis of flexible forest management rules for adaptive stand management. & Results The developed management rules defined the basal area limit for thinning, the thinning intensity, the mean tree diameter at which regeneration cuttings should start, and the basal area below which a salvage cutting should be done. Fire risk was not a significant predictor of the models for thinning and final cutting rules. & Conclusion The presented rules provide a flexible tool for forest management during the stand development and under changing conditions when the management objective is to maximize economic profitability of timber production.
Sammendrag
This study deals with the composition of corporate boards and examines the impact of independent (outside) and inside directors. We analyze the effect of independent and representative board members on firm performance and shareholder protection. Overseeing the CEO to ensure value maximization is one of the key functions of boards. Hence, boards appear as a protective mechanism that protects shareholder rights. With this reasoning regulators promote independent directors at boardrooms. The literature corroborates the notion that independent directors are instrumental in mitigating agency problems. At the same time, increasing worker representation has been considered as a mechanism to contain, or balance the power of controlling shareholders for big companies. In Norway, employee representation in boards has been promoted by the legislation long before. Employee representatives have insider information about the companies and leaves little room for executives to mislead the board. For companies that adopt the gender balance law, and change their boards, we look at the impact of outsiders. We take the insiders into consideration by controlling for the board ownership, and use the incremental effect of female additions to the board as variable capturing the outsider impact. We examine the explanatory power of outsiders at board over the value and tax returns of the company. Conversely, we try to see how the employee representatives are related with firm fundamentals. For the companies that change their organizational form, we gauge the differential impact of employee representation when we control for other factors. The key posits are that employee representatives can protect employee rights, alleviate layoffs, and moderate the executive pay. This view has found audience among policy makers recently. Preliminary results demonstrate that increasing outside and independent directors have a positive effect on the firm value. Furthermore, independent board directors are essential in promoting efficient outcomes. Further, they are instrumental in returning the value to shareholders, limiting the executive compensation, and curbing the relative tax burden.
Forfattere
H Egelyng Anita Romsdal H.O. Hansen Rasa Slizyte Ana Karina Carvajal Laura Jouvenot Marie Hebrok Kaisu Honkapää Jens Petter Wold Randi Seljåsen Marit AursandSammendrag
A circular bioeconomy has become a global aspiration for governments in Europe and around the globe. This article pursues research questions concerning concrete innovations aiming to create bioeconomic transition options in Norway and presents results from a transdisciplinary investigation of Norwegian food industry cases involving processing of fish, meat, fruit, and vegetable co-streams aiming to capture or even increase use and value of residues from processing. It shows that while objectives of avoiding food losses and transforming co-streams to new products of higher value characterizes the poultry industry case and part of the ‘blue’ sector, challenges remain particularly in the ‘whitefish’ area where - also at the global level - a high share of fish resources ends as rest raw materials, i.e. not fully utilised. The investigation targeted strategic cases of innovations enabling alternative uses of co-streams: automation and scanning technologies for fractioning raw materials and co-streams into different qualities, a collection system for fish rest raw materials at sea, enzymatic hydrolysis, use of second grade vegetables for smoothies and potato peels for biodegradable plastics in the vegetable (potato) processing industries. The article shows how these innovations enable cascading and valorisation of co-streams and why an upcycling potential exists as well. Its main contribution is in demonstrating feasibility of transdisciplinary research and innovative options for bioeconomic transition towards sustainability.
Sammendrag
Insulation is an essential component of nest structure that helps provide incubation requirements for birds. Many species of waterfowl breed in high latitudes where rapid heat loss can necessitate a high energetic input from parents and use down feathers to line their nests. Common eider Somateria mollissima nest down has exceptional insulating properties but the microstructural mechanisms behind the feather properties have not been thoroughly examined. Here, we hypothesized that insulating properties of nest down are correlated to down feather (plumule) microstructure. We tested the thermal efficiency (fill power) and cohesion of plumules from nests of two Icelandic colonies of wild common eiders and compared them to properties of plumules of wild greylag goose Anser anser. We then used electron microscopy to examine the morphological basis of feather insulating properties. We found that greylag goose down has higher fill power (i.e. traps more air) but much lower cohesion (i.e. less prone to stick together) compared to common eider down. ese differences were related to interspecific variation in feather microstructure. Down cohesion increased with the number of barbule microstructures (prongs) that create strong points of contact among feathers. Eider down feathers also had longer barbules than greylag goose down feathers, likely increasing their air-trapping capacity. Feather properties of these two species might reflect the demands of their contrasting evolutionary history. In greylag goose, a temperate, terrestrial species, plumule microstructure may optimize heat trapping. In common eiders, a diving duck that nests in arctic and subarctic waters, plumule structure may have evolved to maximize cohesion over thermal insulation, which would both reduce buoyancy during their foraging dives and enable nest down to withstand strong arctic winds.
Forfattere
Kris Van Looy Johan Bouma Michael Herbst John Koestel Budiman Minasny Umakant Mishra Carsten Montzka Attila Nemes Yakov A. Pachepsky José Padarian Marcel G. Schaap Brigitta Tóth Anne Verhoef Jan Vanderborght Martine J. van der Ploeg Lutz Weihermüller Steffen Zacharias Yonggen Zhang Harry VereeckenSammendrag
Soil, through its various functions, plays a vital role in the Earth’s ecosystems and provides multiple ecosystem services to humanity. Pedotransfer functions (PTFs) are simple to complex knowledge rules that relate available soil information to soil properties and variables that are needed to parameterize soil processes. In this paper, we review the existing PTFs and document the new generation of PTFs developed in the different disciplines of Earth system science. To meet the methodological challenges for a successful application in Earth system modeling, we emphasize that PTF development has to go hand in hand with suitable extrapolation and upscaling techniques such that the PTFs correctly represent the spatial heterogeneity of soils. PTFs should encompass the variability of the estimated soil property or process, in such a way that the estimation of parameters allows for validation and can also confidently provide for extrapolation and upscaling purposes capturing the spatial variation in soils. Most actively pursued recent developments are related to parameterizations of solute transport, heat exchange, soil respiration, and organic carbon content, root density, and vegetation water uptake. Further challenges are to be addressed in parameterization of soil erosivity and land use change impacts at multiple scales. We argue that a comprehensive set of PTFs can be applied throughout a wide range of disciplines of Earth system science, with emphasis on land surface models. Novel sensing techniques provide a true breakthrough for this, yet further improvements are necessary for methods to deal with uncertainty and to validate applications at global scale.
Sammendrag
Currently, sugar snap peas are harvested manually. In high-cost countries like Norway, such a labour-intensive practise implies particularly large costs for the farmer. Hence, automated alternatives are highly sought after. This project explored a concept for robotic autonomous identification and tracking of sugar snap pea pods. The approach was based on a combination of visible–near infrared reflection measurements and image analysis, along with visual servoing. A proof-of-concept harvesting platform was implemented by mounting a robotic arm with hand-mounted sensors on a mobile unit. The platform was tested under plastic greenhouse conditions on potted plants of the sugar snap pea variety Cascadia using LED-lights and a partial shade. The results showed that it was feasible to differentiate the pods from the surrounding foliage using the light reflection at the spectral range around 970 nm combined with elementary image segmentation and shape modelling methods. The proof-of-concept harvesting platform was tested on 48 representative agricultural environments comprising dense canopy, varying pod sizes, partial occlusions and different working distances. A set of 104 images were analysed during the teleoperation experiment. The true positive detection rate was 93 and 87% for images acquired at long distances and at close distances, respectively. The robot arm achieved a success rate of 54% for autonomous visual servoing to a pre-grasp pose around targeted pods on 22 untouched scenarios. This study shows the potential of developing a prototype robot for semi-automated sugar snap pea harvesting.