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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.

2017

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Abstract

Shallow (<1 m deep) snowpacks on agricultural areas are an important hydrological component in many countries, which determines how much meltwater is potentially available for overland flow, causing soil erosion and flooding at the end of winter. Therefore, it is important to understand the development of shallow snowpacks in a spatially distributed manner. This study combined field observations with spatially distributed snow modelling using the UEBGrid model, for three consecutive winters (2013–2015) in southern Norway. Model performance was evaluated by comparing the spatially distributed snow water equivalent (SWE) measurements over time with the simulated SWE. UEBGrid replicated SWE development at catchment scale with satisfactory accuracy for the three winters. The different calibration approaches which were necessary for winters 2013 and 2015 showed the delicacy of modelling the change in shallow snowpacks. Especially the refreezing of meltwater and prohibited runoff and infiltration of meltwater by frozen soils and ice layers can make simulations of shallow snowpacks challenging.

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Abstract

This study presents an approach for predicting stand-level forest attributes utilizing mobile laser scanning data collected as a nonprobability sample. Firstly, recordings of stem density were made at point locations every 10th metre along a subjectively chosen mobile laser scanning track in a forest stand. Secondly, kriging was applied to predict stem density values for the centre point of all grid cells ina5m×5m lattice across the stand. Thirdly, due to nondetectability issues, a correction term was computed based on distance sampling theory. Lastly, the mean stem density at stand level was predicted as the mean of the point-level predictions multiplied with the correction factor, and the corresponding variance was estimated. Many factors contribute to the uncertainty of the stand-level prediction; in the variance estimator, we accounted for the uncertainties due to kriging prediction and due to estimating a detectability model from the laser scanning data. The results from our new approach were found to correspond fairly well to estimates obtained using field measurements from an independent set of 54 circular sample plots. The predicted number of stems in the stand based on the proposed methodology was 1366 with a 12.9% relative standard error. The corresponding estimate based on the field plots was 1677 with a 7.5% relative standard error.

Abstract

Enzymes are major components of organism defense against toxic chemicals in their environment. Despite the passage of more than 200 million years of life presence these enzymes now play an important role in detoxifying chemicals man-made addiction and it may be a useful biomarker. Lactate dehydrogenase (LDH or LD) is intracellular enzyme year found early in all living cells (animals, plants, and prokaryotes). LDH catalyzes the conversion of pyruvic acid to lactic acid and back, as it converts NAD + to NADH and back. A dehydrogenase enzyme transfers a hydride from one molecule to another. LDH enzyme exists in four distinct classes: first is NAD (P) -dependent L-lactate dehydrogenase; other LDHs act on D-lactic and / or is dependent on cytochome C: Dlactate dehydrogenase (cytochome) and L-lactate (L-lactate dehydrogenase (cytochome). LDH is expressed extensively in body tissues, such as blood cells and heart muscle. Lactate dehydrogenase (LDH) is widely distributed throughout the body, as seen mainly in the kidney, myocardium, skeletal muscle, brain, liver and lungs. Because it is released during tissue damage, it is a marker of common injuries such as heart failure and disease.