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.
2016
Forfattere
Agnar KvalbeinSammendrag
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Redaktører
Geir-Harald StrandSammendrag
Det er ikke registrert sammendrag
Sammendrag
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Sammendrag
Winching is common in small-scale forest operations, especially on steep slopes, where tractors cannot reach the logs inside the forest. In this case, logs are dragged to the roadside with tractor-mounted winches, for later collection by transportation units. Winching is a heavy task, posing a high physiological stress on winching crew members. The aim of this study was to investigate the relationship between experienced workload, work conditions and operator fitness. The study confirmed the assumption that fit, young operators experience a lower workload than older ones. Workload depends on winching direction, and it is higher when winching downhill than when winching uphill. Results confirmed that gravity is the main factor, and it has a stronger effect than task type and tool weight. Walking uphill with no tools is heavier than walking downhill and carrying a steel cable. As a consequence, tool weight reduction can only palliate the problem, without solving it. Winching crews should be composed of fit, young workers. When the task is assigned to older workers, it is necessary to allow longer rest breaks, accepting a lower productivity. Keywords: steep terrain, winching, workload, heart rate
Forfattere
Z. Kruma L. Tomsone T. Kince R. Galoburda S. Senhofa M. Sabovics E. Straumite Ievina SturiteSammendrag
Det er ikke registrert sammendrag
Forfattere
Hugh Cross Ed Biffin Kor-Jent Van Dijk Andrew Lowe Michelle WaycottSammendrag
Det er ikke registrert sammendrag
Forfattere
Yang Shao Gregory Taff Jie Ren James B. CampbellSammendrag
Det er ikke registrert sammendrag
Sammendrag
This paper describes a method in which horses learn to communicate by touching different neutral visual symbols, in order to tell the handler whether they want to have a blanket on or not. Horses were trained for 10–15 min per day, following a training program comprising ten steps in a strategic order. Reward based operant conditioning was used to teach horses to approach and touch a board, and to understand the meaning of three different symbols. Heat and cold challenges were performed to help learning and to check level of understanding. At certain stages, a learning criterion of correct responses for 8–14 successive trials had to be achieved before proceeding. After introducing the free choice situation, on average at training day 11, the horse could choose between a “no change” symbol and the symbol for either “blanket on” or “blanket off” depending on whether the horse already wore a blanket or not. A cut off point for performance or non-performance was set to day 14, and 23/23 horses successfully learned the task within this limit. Horses of warm-blood type needed fewer training days to reach criterion than cold-bloods (P < 0.05). Horses were then tested under differing weather conditions. Results show that choices made, i.e. the symbol touched, was not random but dependent on weather. Horses chose to stay without a blanket in nice weather, and they chose to have a blanket on when the weather was wet, windy and cold (χ2 = 36.67, P < 0.005). This indicates that horses both had an understanding of the consequence of their choice on own thermal comfort, and that they successfully had learned to communicate their preference by using the symbols. The method represents a novel tool for studying preferences in horses.
Forfattere
Atle Mysterud William Ryan Easterday Vetle Malmer Stigum Anders Aas Erling Meisingset Hildegunn ViljugreinSammendrag
Global environmental changes are causing Lyme disease to emerge in Europe. The life cycle of Ixodes ricinus, the tick vector of Lyme disease, involves an ontogenetic niche shift, from the larval and nymphal stages utilizing a wide range of hosts, picking up the pathogens causing Lyme disease from small vertebrates, to the adult stage depending on larger (non-transmission) hosts, typically deer. Because of this complexity the role of different host species for emergence of Lyme disease remains controversial. Here, by analysing long-term data on incidence in humans over a broad geographical scale in Norway, we show that both high spatial and temporal deer population density increase Lyme disease incidence. However, the trajectories of deer population sizes play an overall limited role for the recent emergence of the disease. Our study suggests that managing deer populations will have some effect on disease incidence, but that Lyme disease may nevertheless increase as multiple drivers are involved.
Forfattere
R. Venancio G.J. Moraes R.C. Castilho N.S. Iwanicki G.F. Moreira Lise Grøva Karin Westrum Ingeborg KlingenSammendrag
Tick-borne diseases, such as anaplasmosis and babesiosis, are of major concern for Norwegian sheep farmers. Ticks can be controlled on and off the host, usually with the long-term, high-rotation use of chemicals. Fungal pathogens, predatory mites and ants are thought to be important tick killers in nature. However, the prevalence and diversity of predatory mites in tick habitats has barely been evaluated. It is known that most soil mite species of the cohort Gamasina (order Mesostigmata) are predators. Until now, 220 mesostigmatid species have been reported from Norway, most of them belonging to the Gamasina. One of the first recommended steps in a biological control program involves the determination of the fauna in the pest habitat. The objective of this study was to determine the groups of gamasines co-occurring with I. ricinus in sheep grazing areas in Isfjorden and Tingvoll in Western Norway. A total of 2,900 gamasines of 12 families was collected. The most numerous families were Parasitidae (46.9%) and Veigaiidae (25.7%), whereas the most diverse families were Laelapidae, Macrochelidae, Parasitidae and Zerconidae. Our results showed that the tick density was significantly related only to locality, elevation and rainfall. Differences in the prevailing environmental conditions resulted in more outstanding differences between Gamasina abundances than diversities. Based on our present knowledge of the potential of different gamasine groups as biological control agents, the results suggested that laelapid mites should be among the priority groups to be further evaluated for their role in the natural control of I. ricinus in Norway.