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.
2015
Authors
Jørgen A.B. Mølmann Anne Linn Hykkerud Gunnar Bengtsson Randi Seljåsen Per Lea Josefine Skaret Tor J. JohansenAbstract
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Abstract
The analysis of temporal geospatial data has provided important insights into global vegetation dynamics, particularly the interaction among different variables such as precipitation and vegetation indices. Nevertheless, this analysis is not a straightforward task due to the complex relationships among different systems driving the dynamics of the observed variables. Aiming at automatically extracting information from temporal geospatial data, we propose a new approach to detect stochastic and deterministic patterns embedded into time series and illustrate its effectiveness through an analysis of global geospatial precipitation and vegetation data captured over a 14 year period. By knowing such patterns, we can find similarities in the behavior of different systems even if these systems are characterized by different dynamics. In addition, we developed a novel determinism measure to evaluate the relative contribution of stochastic and deterministic patterns in a time series. Analyses showed that this measure permitted the detection of regions on the global map where the radiation absorbed by the vegetation and the incidence of rain occur with similar patterns of stochasticity. The methods developed in this study are generally applicable to any spatiotemporal data set and may be of particular interest for the analysis of the vast amount of remotely sensed geospatial data currently being collected routinely as part of national and international monitoring programs.
Authors
Erik Biørn Hild-Marte BjørnsenAbstract
Some labour market consequences of transitions in the agriculture sector are examined by combining 20-year unbalanced panel data from Norwegian farm households and logit modeling of transition probabilities. The multi-dimensionality of the problem follows from two decision makers having four possible choices in each period: the farm operator and spouse can be working fully on the farm or having supplementary outside occupation. Transitions are modeled by five logit models. The most flexible model has a high number of parameters. Overall, the results indicate that transitions have mainly been directed towards the state where both partners work off the farm. An increasing livestock reduces the probability of moving to states with substantial off-farm labour participation. Increasing farm size tends to have the opposite effect. Recent on-farm investments come out with ambiguous effects. Having children seems to motivate operators to withdraw from off-farm labour and spouses to stay in or enter off-farm employment.
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Authors
Stefanos Xenarios Heracles PolatidisAbstract
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Abstract
Solberg, Svein; Weydahl, Dan Johan; Astrup, Rasmus Andreas. Temporal stability of X-band single-pass InSAR heights in a spruce forest: Effects of acquisition properties and season. IEEE Transactions on Geoscience and Remote Sensing 2014 ;Volum 53.(3) s. 1607-1614
Authors
Mohammad Tahir Waheed Hammad Ismail Johanna Gottschamel Bushra Mirza Andreas G. LösslAbstract
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Authors
Mark Hughes Callum Aidan Stephen Hill Alexander PfriemAbstract
The mechanical properties of thermally modified wood are discussed with regard to toughness. The molecular origins of the mechanical properties and, in particular, the role of the hemicelluloses are considered. The important role of water and its interaction with the cell wall components is also examined. The properties are discussed from the point of view of composite theory, with the three main macromolecular components acting as reinforcement, matrix and interfacial coupling agent. The important role that hemicelluloses play as a coupling agent between the cellulosic microfibril reinforcement and the lignin-rich matrix is highlighted. Destruction of the hemicelluloses during the thermal modification process has a profound effect upon the mechanical behaviour.
Abstract
No abstract has been registered