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.
2018
Authors
Pierrick Francois Denis Stévant Erlend Indergård Aðalheiður Ólafsdóttir Hélène Marfaing Wenche Merete Emblem Larssen Joël Fleurence Michael Roleda Turid Rustad Rasa Slizyte Tom Ståle NordtvedtAbstract
The effects of convective air-drying at 25, 40, and 70 °C and freeze-drying on the quality of the edible kelp Saccharina latissima to be used for food were investigated. Based on the analysis of the carbohydrate and amino acid profiles, as well as polyphenol, fucoxanthin, and ash contents, no significant differences were detected among sample groups, and air-drying up to 70 °C results in equally nutritious products at shorter processing times. Only the iodine content was found lower in freeze-dried compared to air-dried samples. The swelling capacity of the air-dried samples was significantly lower than in freeze-dried samples, particularly at high temperatures (40 and 70 °C), reflecting alteration of the physico-chemical properties of the seaweed during air-drying (attributed to product shrinkage) and reduced capacity of the final product to rehydrate. Structural differences between air-dried products at 25 and 70 °C may explain the differences in mouthfeel perception (dissolving rate) among the two sample groups observed during a sensory evaluation. Overall, the drying temperature within this range did not alter neither the aroma (i.e. odor) nor the flavor intensity of the product. In food applications where the product’s mechanical properties (e.g. porosity) are essential, freeze-drying, and to a lesser extent, air-drying at low temperatures, will result in higher quality products than air-drying at higher temperatures.
Authors
Anastasia Georgantzopoulou Christian Vogelsang Claire Coutris Kuria Ndungu Patricia Almeida Carvalho Andy Booth Kevin V Thomas Ailbhe MackenAbstract
The majority of nanomaterials (NMs) used in industrial and commercial applications are likely to enter the wastewater stream and reach wastewater treatment plants (WWTPs). In Oslo, Norway, the WWTPs receive both municipal and industrial wastewater. The treated effluents are discharged to aquatic recipients and the stabilised sludges are applied on agricultural land, however, the transformation of the particles and the potential hazard they pose in these compartments are poorly understood. The overall goal of this study was to elucidate the behavior of Ag and TiO2 NPs during biological wastewater treatment, and investigate the subsequent effects of transformed particles present in the effluent and sludge relative to their pristine counterparts. A laboratory-scale wastewater treatment system was established and combined with a battery of ecotoxicological assays and characterization techniques. The system was based on activated sludge treatment with a pre-denitrification system and fed with synthetic wastewater spiked daily with 10 µg Ag NPs/L (PVP coated, 25 nm, nanoComposix) and 100 µg TiO2 NPs/L (5 nm, NM-101, JRC) over a period of 5 weeks. Samples from all reactors, including the effluent, were collected weekly and analyzed by sequential filtration and inductively coupled plasma mass spectrometry (ICP-MS) to determine the NP fractionation and partitioning. Transmission electron microscopy and single particle ICP-MS were performed on selected samples. The effects of transformed particles present in the effluents were assessed using a battery of bioassays including freshwater and marine algae (growth inhibition, reactive oxygen species -ROS- formation), crustaceans and in vitro models of relevance for NP toxicity assessment (RTgill-W1 cell line, metabolic activity, epithelial integrity, ROS formation, gene expression). The effects of the aged particles through biosolids application were evaluated using coelomocytes, primary cells involved in immune defense mechanisms, isolated from the exposed earthworms Eisenia fetida. The observed effects were organism-dependent, with bottom feeding organisms and algae being more sensitive. The in vitro models offered a useful tool for the assessment of environmental samples. Through a relevant exposure scenario, this study adds useful pieces to our still fragmentary understanding of the environmental fate of weathered NPs.
Authors
Isabella BørjaAbstract
No abstract has been registered
Abstract
Large areas of farmland are abandoned in Norway, which for various reasons are regarded as undesirable. Loss of farmlandmay have negative implications for biodiversity and ecosystem function and food production potential. The objectives of this study were to assess forage mass production and utilization, botanical composition, lamb performance, and grazing distribution pattern when reintroducing livestock grazing to an abandoned grassland. The study area was located in Central Norway, unmanaged for 12 years. Sheep grazed the area for 10 weeks in 2013 and 4 weeks in spring and autumn, respectively, in 2014 and 2015. During the summer of 2014 and 2015, the area was subjected to the following replicated treatments: (1) No grazing, (2) grazing with heifers, and (3) grazing with ewes and their offspring. The stocking rate was similar in the grazed treatments. Forage biomass production and animal intake were estimated using grazing exclosure cages and botanical composition by visual assessment. Effect on lamb performance was evaluated by live weight gain and slaughter traits in sheep subjected to three treatments: (1) Common farm procedure with summer range pasturing, (2) spring grazing period extended by 1 month on the abandoned grassland before summer range pasturing, and (3) spring and summer grazing on the abandoned grassland. Grazing distribution patterns were studied using GPS position collars on ewes. Total annual biomass production was on average 72% higher with summer grazing than without. Annual consumption and utilization was on average 218 g DM/m2 and 70% when summer grazed, and 25 g DM/m2 and 18% without grazing, respectively. Botanical composition did not differ between treatments. Live weight gain was higher in lambs subjected to an extended spring grazing period (255 g/d) compared to common farm practice (228 g/d) and spring and summer grazing on the abandoned grassland (203 g/d), and carcass value was 14% higher in lambs on extended spring grazing compared to common farm practice. In autumn, sheep preferred to graze areas grazed by sheep during summer. Re-introduction of grazing stimulated forage production, and extended spring grazing improved performance in lambs. This study has quantified the value of abandoned grassland as a feed resource.
Abstract
Changes in the local flora of mountains are often explained by climate warming, but changes in grazing regimes may also be important. The aim of this study was to evaluate whether the alpine flora on summits in the Tatra Mts, Poland and Slovakia, has changed over the last 100 years, and if the observed changes are better explained by changes in sheep grazing or climate. We resurveyed the flora of 14 mountain summits initially investigated in the years 1878–1948. We used ordination methods to quantify changes in species composition. We tested whether changes in plant species composition could be explained by cessation of grazing and climate change, and whether these factors have influenced shifts in Ellenberg’s plant ecological indicator values and Raunkiaer’s life forms. Changes in alpine flora were greater on lower elevation summits, and lower on summits less accessible for sheep. More accessible summits were associated with a decrease in mean values of plant species’ light ecological indicator values over time, and a concurrent increase in temperature and nitrogen ecological indicator values. No significant relationships were found between accessibility for sheep and changes in Raunkiaer’s life-forms. Greater accessibility for sheep (meaning high historical grazing pressure) led to greater compositional changes of mountain summits compared with summits with low accessibility. Our results suggest that cessation of sheep grazing was the main factor causing changes in the species composition of resurveyed mountain summits in the Tatra Mts, while climate change played a more minor role.
Authors
Synnøve Rivedal Samson Øpstad Torbjørn Haukås Johannes Deelstra Peter Dörsch Trond Børresen Sissel Hansen Sverre HeggsetAbstract
No abstract has been registered
Authors
Habtamu AlemAbstract
This paper examines the recent advances in stochastic frontier models and its implications for the performance of the Norwegian crop producing farms. Unlike the previous studies, we used a cost function in multiple input-output frameworks to estimate both long-run (persistent) and short-run (transient) inefficiency. The empirical analysis is based on unbalanced farm-level panel data for 1991-2013 from 455 Norwegian farms specialized in crop production with 3885 observations. We estimated seven SF panel data models grouped into four categories regarding the assumptions used to the nature of inefficiency. The estimated cost efficiency scores varied from 53 % to 95%, showing that the results are sensitive to how the inefficiency is modeled and interpreted. Keywords: cost function, short and long-run inefficiency, agriculture, panel data
Abstract
No abstract has been registered
Abstract
No abstract has been registered
Abstract
No abstract has been registered