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
Esther Bloem Annette Dathe Attila Nemes Perrine Marguerite Fernandez Helen French Matthew Patterson Daniel GiminezSammendrag
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Sammendrag
The key factor for autonomous navigation is efficient perception of the surroundings,while being able to move safely from an initial to a final point. We deal in this paper with a wheeled mobile robot working in a GPS-denied environment typical for a greenhouse. The Hector Simultaneous Localization and Mapping (SLAM) approach is used in order to estimate the robots’ pose using a LIght Detection And Ranging (LIDAR) sensor. Waypoint following and obstacle avoidance are ensured by means of a new artificial potential field (APF) controller presented in this paper. The combination of the Hector SLAMand the APF controller allows themobile robot to performperiodic tasks that require autonomous navigation between predefined waypoints. It also provides themobile robot with a robustness to changing conditions thatmay occur inside the greenhouse, caused by the dynamic of plant development through the season. In this study, we show that the robot is safe to operate autonomously with a human presence, and that in contrast to classical odometrymethods, no calibration is needed for repositioning the robot over repetitive runs. We include here both hardware and software descriptions, as well as simulation and experimental results.
Forfattere
C.A. Baroffio L. Sigsgaard E.J. Ahrenfeldt Anna-Karin Borg-Karlson Sara Andrea Bruun J.V. Cross M.T. Fountain D. Hall R. Mozuraitis B. Ralle Nina Trandem Atle WibeSammendrag
Most horticultural crops are attacked by more than one insect pest. As broad-spectrum chemical control options are becoming increasingly restricted, there is a need to develop novel control methods. Semiochemical attrac- tants are available for three important horticultural pests, strawberry blossom weevil, Anthonomus rubi Herbst (Coleoptera: Curculionidae), European tarnished plant bug, Lygus rugulipennis Poppius (Hemiptera: Miridae) and raspberry beetle, Byturus tomentosus deGeer (Coleoptera: Byturidae). Traps targeting more than one pest species would be more practical and economical for both monitoring and mass trapping than traps for single-species. In this study we aimed to (1) improve the effectiveness of existing traps for insect pests in strawberry and raspberry crops by increasing catches of each species, and (2) test if attractants for two unrelated pest species could be combined to capture both in the same trap without decreasing the total catches. Field tests were carried out in four European countries and different combinations of semiochemicals were compared. A volatile from straw- berry flowers, 1,4 dimethoxybenzene (DMB), increased the attractiveness of the aggregation pheromone to both sexes of A. rubi. The host-plant volatile, phenylacetaldehyde (PAA), increased the attraction of female L. rugu- lipennis to the sex pheromone, and, in strawberry, there was some evidence that adding DMB increased catches further. Traps baited with the aggregation pheromone of A. rubi, DMB, the sex pheromone of L. rugulipennis and PAA attracted both target species to the same trap with no significant difference in catches compared to those single-species traps. In raspberry, catches in traps baited with a combination of A. rubi aggregation pheromone, DMB and the commercially available lure for B. tomentosus, based on raspberry flower volatiles, were similar to those in single-species traps. In both crops the efficiency of the traps still needs improvement, but the multi- species traps are adequate for monitoring and should not lead to confusion for the user as the target species are easy to distinguish from each other.
Sammendrag
Remote sensing observations provide important information about vegetation and carbon dynamics on large scales, flux towers in situ measurements at the plot scale. Events important for ecological processes, such as hydrometeorological extremes, often happen at spatiotemporal scales between those covered by these two data sources. We discuss the event detection rates of ecological in situ networks as a function of their size and design. Using extreme reductions of the Fraction of Absorbed Photosynthetically Active Radiation (FAPAR), available from satellite missions, as a proxy for substantial losses in Gross Primary Productivity (GPP), we rank historical events according to their severity, and show how many would have been detected with a given number of randomly placed sites, discuss the problem of clustering of sites, and compare the theoretical results with the existing networks FLUXNET and NEON. The further spatio-temporal expansion of the ICOS network should carefully consider the size distribution of extreme events in order to be able to monitor their impacts on the terrestrial biosphere.
Forfattere
Holger LangeSammendrag
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Forfattere
Stefano PulitiSammendrag
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Forfattere
Maryia Khomich Filipa Cox Carrie Joy Andrew Tom Andersen Håvard Kauserud Marie Louise DaveySammendrag
Insufficient reference database coverage is a widely recognized limitation of molecular ecology ap-proaches which are reliant on database matches for assignment of function or identity. Here, we use datafrom 65 amplicon high-throughput sequencing (HTS) datasets targeting the internal transcribed spacer(ITS) region of fungal rDNA to identify substrates and geographic areas whose underrepresentation in theavailable reference databases could have meaningful impact on our ability to draw ecological conclu-sions. A total of 14 different substrates were investigated. Database representation was particularly poorfor the fungal communities found in aquatic (freshwater and marine) and soil ecosystems. Aquaticecosystems are identified as priority targets for the recovery of novel fungal lineages. A subset of the datarepresenting soil samples with global distribution were used to identify geographic locations andterrestrial biomes with poor database representation. Database coverage was especially poor in tropical,subtropical, and Antarctic latitudes, and the Amazon, Southeast Asia, Australasia, and the Indian sub-continent are identified as priority areas for improving database coverage in fungi.
Sammendrag
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Forfattere
Kjell Andreassen Bernt-Håvard ØyenSammendrag
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Forfattere
Angela Koort Ulvi Moor Priit Poldma Clive Kaiser Marge StarastSammendrag
The aim of the study was to determine the effect of modified atmosphere (MA) packages on the external quality of organically grown lowbush blueberry and half-highbush blueberry (’Northblue’) and the nutritional value of the fruits. Fruits were divided into plastic punnets and stored as follows: regular atmosphere (RA), punnets without packing; punnets sealed in a low-density polyethylene (LDPE, Estiko) bag; punnets sealed in an Xtend® blueberry bag (Stepac). Fruits were stored at 3 ± 1 ◦C. Compared to RA conditions, the Xtend® package prolonged the postharvest life for 15 days for lowbush and 9 days for half-highbush blueberries. Fruit dry matter (DM) and titratable acidity (TA) were higher in the Xtend® package. Fruit SSC decreased in the LDPE packages and increased in the Xtend® packages during storage. Based on the decreased soluble solids content (SSC) and titratable acidity (TA) ratio (SSC:TA) values during storage, it can be concluded that the taste of the fruits became sourer in all packages. Anthocyanin biosynthesis of lowbush blueberries was suppressed in MA, but this effect was not noticed for ‘Northblue’. Regarding fruit firmness, shrivelling, and decay, there were significant differences between the MA packages, but the genetic differences were more important: half-highbush blueberry fruits were firmer and less shrivelled.