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.
2018
Forfattere
Anders Kvalvåg Wollan Harald Bratli Anders Bryn Eva Lieungh Eriksen Anne B. Nilsen Heidrun Asgeirsdatter Ullerud Rune HalvorsenSammendrag
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Forfattere
Mihaela-Olivia Dobrica Catalin Lazar Lisa Paruch Andre van Eerde Jihong Liu Clarke Catalin Tucureanu Iuliana Caras Sonya Ciulean Adrian Onu Vlad Tofan Alexandru Branzan Stephan Urban Crina Stavaru Norica Branza-NichitaSammendrag
Hepatitis B Virus (HBV) infection can be prevented by vaccination. Vaccines containing the small (S)envelope protein are currently used in universal vaccination programs and achieve protective immuneresponse in more than 90% of recipients. However, new vaccination strategies are necessary for successfulimmunization of the remaining non- or low-responders. We have previously characterized a novel HBVchimeric antigen, which combines neutralization epitopes of the S and the preS1 domain of the large (L)envelope protein (genotype D). The S/preS121–47chimera produced in mammalian cells and Nicotianabenthamiana plants, induced a significantly stronger immune response in parenterally vaccinated micethan the S protein. Here we describe the transient expression of the S/preS121–47antigen in an edibleplant, Lactuca sativa, for potential development of an oral HBV vaccine. Our study shows that oral admin-istration of adjuvant-free Lactuca sativa expressing the S/preS121–47antigen, three times, at 1lg/dose,was sufficient to trigger a humoral immune response in mice. Importantly, the elicited antibodies wereable to neutralize HBV infection in an NTCP-expressing infection system (HepG2-NTCP cell line) moreefficiently than those induced by mice fed on Lactuca sativa expressing the S protein. These results sup-port the S/preS121–47antigen as a promising candidate for future development as an edible HBV vaccine.
Forfattere
Anestis Karkanis Georgia Ntatsi Liga Lepse Juan A. Fernández Ingunn M. Vågen Boris Rewald Ina Alsina Arta Kronberga Astrit Balliu Margit Olle Gernot Bodner Laila Dubova Eduardo Rosa Dimitrios SavvasSammendrag
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Sammendrag
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Sammendrag
Horizontal Visibility Graphs (HVGs) are a recently developed method to construct networks from time series. The values of the time series are considered as the nodes of the network and are linked to each other if there is no larger value between them, such as they can “see” each other. The network properties reflect the nonlinear dynamics of the time series. For some classes of stochastic processes and for periodic time series, analytical results can be obtained for network-derived quantities such as the degree distribution, the local clustering coefficient distribution, the mean path length, and others. HVGs have the potential to discern between deterministic-chaotic and correlated-stochastic time series. Here, we investigate the sensitivity of the HVG methodology to properties and pre-processing of real-world data, i.e., time series length, the presence of ties, and deseasonalization, using a set of around 150 runoff time series from managed rivers at daily resolution from Brazil with an average length of 65 years. We show that an application of HVGs on real-world time series requires a careful consideration of data pre-processing steps and analysis methodology before robust results and interpretations can be obtained. For example, one recent analysis of the degree distribution of runoff records reported pronounced sub-exponential “long-tailed” behavior of North American rivers, whereas another study of South American rivers showed hyper-exponential “short-tailed” behavior resembling correlated noise.We demonstrate, using the dataset of Brazilian rivers, that these apparently contradictory results can be reconciled by minor differences in data-preprocessing (here: small differences in subtracting the seasonal cycle). Hence, data-preprocessing that is conventional in hydrology (“deseasonalization”) changes long-term correlations and the overall runoff dynamics substantially, and we present empirical consequences and extensive simulations to investigate these issues from a HVG methodological perspective. After carefully accounting for these methodological aspects, the HVG analysis reveals that the river runoff dataset shows indeed complex behavior that appears to stem from a superposition of short-term correlated noise and “long-tailed behaviour,” i.e., highly connected nodes. Moreover, the construction of a dam along a river tends to increase short-term correlations in runoff series. In summary, the present study illustrates the (often substantial) effects of methodological and data-preprocessing choices for the interpretation of river runoff dynamics in the HVG framework and its general applicability for real-world time series.
Sammendrag
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Forfattere
Habtamu AlemSammendrag
In this article, we estimate the progress of Total Factor Productivity (TFP) in the Norwegian grain production sector. Previous studies conducted in TFP estimation can be criticized for estimated production function relied on the assumption that the underlying technology is the same for all regions and firms face similar environmental conditions. In reality, agricultural firms in different regions resource endowment, adoption of new technology, and innovation might be different because of farmers face different production opportunities. For this study, we classified the country into two main grain producing regions with district level of development, and hence production technologies. We used farm level balanced panel data for 19 years (1996-2014) with 1463 observations from farms specialized in grain production. We applied the ‘true' fixed effect stochastic frontier model to estimate region level efficiency and source of productivity changes. The result of the analysis shows that there has been a productivity improvement in the sector, and technical change has had the main source of productivity change.
Sammendrag
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Forfattere
Gitte Søndergaard Dorinde Kleinegris Katerina Kousoulaki Nils-Arne Ekerhovd Stig A. Borgvang Kari Skjånes Anne Kjersti UhlenSammendrag
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Forfattere
Stig A. Borgvang Katerina Kousoulaki Anne Kjersti Uhlen Kari Skjånes Sigbjørn Gjelsvik Nils-Arne Ekerhovd Vegard StorslettenSammendrag
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