http://hdl.handle.net/2282/137 Search the Channel search http://teora.hit.no/dspace/simple-search http://hdl.handle.net/2282/548 Title: Blitzfotografering av bevegelige objekter gjennom mikroskop <br/> <br/>Authors: Bjerketvedt, Dag Kjartan <br/> <br/>Abstract: Ordinary microscopes can be adapted to fully automatic photomicroscopes for use with flash. An automatic small film camera with an autodynamic flash and extra equipment for microphotography is necessary. The camera's electronics determine the light intensity from the flash. Wed, 29 Oct 1980 22:58:59 GMT http://hdl.handle.net/2282/545 Title: Collapsing burrow causes death of a Eurasian beaver, Castor fiber <br/> <br/>Authors: Thomsen, Liat R.; Sharpe, Fiona; Rosell, Frank <br/> <br/>Abstract: The death of a Eurasian Beaver Castor fiber caused by a collapsing burrow in southeast Norway is reported. Two days of heavy rainfall had presumably caused the burrow to collapse, suffocating the animal. Wed, 29 Oct 2003 22:58:59 GMT http://hdl.handle.net/2282/539 Title: Simulated winter browsing may lead to induced susceptibility of willows to beavers in spring <br/> <br/>Authors: Veraart, Annelies J.; Nolet, Bart A.; Rosell, Frank; de Vries, Peter P. <br/> <br/>Abstract: Browsing may lead to an induced resistance or susceptibility of the plant to the herbivore. We tested the effect of winter browsing by Eurasian beavers (Castor fiber L., 1758) on food quality of holme willows (Salix dasyclados Wimm.) in and after the following growth season. Shrubs were pruned in February, and new shoots from these (cut) shrubs were compared with those of untreated (uncut) ones in May and November. The shoots were analysed for dry matter, nitrogen, acid detergent fibre, and total phenolics. In May, the leaves from the cut treatment had a better food quality (more water, more nitrogen, and less phenolics) than those from the uncut one. There was in part also a systemic response, with lower total phenolics in both the cut and untreated parts of pruned shrubs (uncut–cut) than in the uncut shrubs. In November, we did not find significant differences in biochemistry of bark among cut, uncut, or uncut–cut treatments. These results are in accordance with a cafeteria experiment in the field: in May the beavers preferred shoots from the cut treatment, but in November they showed no preference. The results suggest that willows invest in compensatory growth rather than a defence response early in the regrowing phase. Sat, 29 Oct 2005 22:58:59 GMT http://hdl.handle.net/2282/538 Title: Resident beavers (Castor canadensis) do not discriminate between castoreum scent marks from simulated adult and subadult male intruders <br/> <br/>Authors: Herr, Jan; Müller-Schwarze, Dietland; Rosell, Frank <br/> <br/>Abstract: Subadult intruding beavers (Castor spp.) could be expected to pose a higher threat than adults to territory holders because, unlike adults who usually own a territory, subadults need to acquire a territory and a mate to reproduce successfully. We tested the responses of territorial beavers (Castor canadensis Kuhl, 1820) to simulated intrusions by adult and subadult males. Territorial intrusion was simulated through scent playback experiments that exposed residents to castoreum from adult and subadult strangers simultaneously. We obtained responses from 13 resident beavers. Neither sniffing response nor physical or total responses differed between castoreum from adults and subadults. This was true for both sexes combined and separate. There was also no significant correlation between the mass of the scent donor and the response intensity. We found no evidence that territorial beavers responded differentially to castoreum scent marks from intruders of different ages. Either beavers consider all strange intruders as posing a high threat and hence do not treat them differentially or castoreum does not contain sufficient information to allow beavers to discriminate between age classes. We suggest that rather than directly assessing intruders by means of intrinsic information contained in the scent mark, beavers assess their competitors through scent matching. Sat, 29 Oct 2005 22:58:59 GMT