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.
2009
Abstract
The common European cerambycid Leiopus nebulosus (Linnaeus, 1758) is herein split into two sibling species. The male genitalia characters, as well as spermathecae in females, were examined and found to provide strong support for this separation. A new species, Leiopus linnei sp. nov., is based on specimens mainly from Scandinavia. The establishment of the new species is supported by DNA barcoding of Scandinavian specimens of L. nebulosus, L. linnei sp. nov., and L. punctulatus (Paykull, 1800). There are significant genetic differences between all these species. The geographical distribution and the bionomy of L. nebulosus and L. linnei sp. nov. are described. The type of Cerambyx nebulosus Linnaeus, 1758 is lost. A neotype of Cerambyx nebulosus, currently Leiopus nebulosus (Linnaeus, 1758), is designated and a redescription of L. nebulosus is presented. A key for the identification of L. nebulosus and L. linnei sp. nov. is provided. The varieties L. nebulosus var. dissimilis Pic, 1889, L. nebulosus var. unifasciatus Pic, 1891, and L. nebulosus var. siculus Pic, 1924 are considered as junior synonyms, syn.nov. of L. nebulosus.
Abstract
Mechanical strength properties are the most important feature of wood in constructions. In decaying wood strength loss can precede mass loss. Hence, both in laboratory and outdoor applications non-destructive measurement methods for early decay detection are in demand. The aim of this study was to evaluate the applicability of ultrasonic pulse propagation as a tool for decay detection in different laboratory setups. A dynamic MOE (MOEdyn) strength test device based on measurement of ultrasonic pulse propagation was used for non-destructive strength evaluation in different exposure situations for Scots pine sapwood. Two different test setups were used. In the first test MOEdyn was measured above fibre saturation. A range of different wood protection treatments were tested according to the terrestrial microcosms (TMC) test, a modified ENV 807. Three different soil types were used: forest soil dominated by white rot, Simlångsdalen test field soil dominated by brown rot and compost soil characterised by a mixture of bacteria and soft rot. Before strength testing the samples were water saturated and MOEdyn was measured above the fibre saturation point at time intervals (0, 8, 16, 24, 32 and 40 weeks) using ultrasound. Comparisons of strength loss were performed between treatments in the different soil types, and strength loss was also compared with mass loss. In the second test MOEdyn were measured below fibre saturation. Ultrasound measurements were performed on 0.5 m pine logs sampled from five trees from the same stand in central Southern Norway. Logs from two of the trees had varying amounts of discoloration due to an incipient attack by the white rot fungus Phlebiopsis gigantea during storage. Amount of visible discoloration had effect on MOEdyn values from measurements on log ends. Transversal measurement of MOEdyn was not successful. In a subsequent water uptake test, logs with discoloration absorbed substantially more water than the rest of the sample. The conclusion of this study was that the use of ultrasonic MOE is applicable as an evaluation tool in early decay detection.
Abstract
No abstract has been registered
Abstract
Due to the exponential increase in production of engineered nanomaterials, concerns are raised about their inevitable spreading and fate in the environment. In this study we examined the uptake and excretion kinetics of cobalt and silver nanoparticles (NPs) in Eisenia fetida, as well as their internal distribution within earthworms. We hypothesised that the uptake, retention time and internal distribution of cobalt and silver depend on their speciation, i.e. whether they are absorbed as ions or nanoparticles. Nanoparticles were subjected to neutron activation prior to the experiment, in order to facilitate tracing and quantification in earthworms by gamma counting and autoradiography. Ions and NPs were added to the food, horse manure (HM). The treatments were Co2+ 0.70 µg/kg HM, CoNP 0.69 mg/kg HM, Ag+ 0.54 mg/kg HM, AgNP 0.45 mg/kg HM, and control. The experiment followed the OECD guidelines, with one month uptake and two months excretion for silver treatments, and four months excretion for cobalt treatments. The patterns of accumulation were highly different for cobalt and silver. The concentration ratios (Bq/g worm / Bq/g food) after one month uptake were 0.93 ± 0.36 and 2.02 ± 0.65 for CoNP and Co2+ respectively, and almost all absorbed CoNP and Co2+ remained within the worms after 4 months excretion. The Ag concentration ratios after one month uptake were 0.015 ± 0.016 and 0.054 ± 0.024 for AgNP and Ag+ respectively, with a subsequent excretion of almost all AgNP and Ag+ within a few days. In addition to information on uptake and excretion kinetics, gamma counting on individual organs, coupled to autoradiography on worm transects gave information on distribution of cobalt and silver NPs within the body, and the target organs for these NPs.
Abstract
Wood is a traditional building material but in general it underlies restrictions in outdoor applications due to its respective durability against microbiological decay. To face this problem, different impregnation systems are applied to enhance the materials\" servicelife. Scots pine (Pinus sylvestris) is the most widely distributed pine in Eurasia and hence easily available. Despite of the previously defined good treatability of Scots pine sapwood, large differences in treatment performance are reported from industry. As process parameters are always adjusted to the material most difficult to treat, permeability variations in wood material are an economical problem. Therefore, it is important to understand the material in order to make a more reasonable material selection possible.....
Authors
Raquel Diaz Øystein Johnsen Josefa Fernandez-LopezAbstract
No abstract has been registered
Authors
Ingerd Skow Hofgaard Katarzyna Marzec Guro Brodal Birgitte Henriksen May Bente Brurberg Anne-Marte TronsmoAbstract
Microdochium nivale (syn. Microdochium nivale var. nivale) and Microdochium majus (syn. Microdochium nivale var. majus) are important pathogens which cause snow mould on grasses and winter cereals. These fungi are also able to cause leaf blotch of oat and seedling blight, foot rot and ear blight in cereals. Although no distinct differences in the host range of M. nivale and M. majus are found, indications for differences in host preferences between these fungal species have previously been discussed. The culture collection at Bioforsk contains about 250 Microdochium sp. isolated from grasses and cereals over the last 20 years. Most of the isolates collected from leaves of cereals displaying snow mould symptoms in spring, were identified as M. nivale (71 %), whereas most of the isolates collected from cereal seeds (mostly wheat) belong to the species M. majus (92 %). All, except one out of the sixty nine Microdochium sp. isolated from grass leaves were identified as M. nivale (99 %). The relatively higher incidence of M. majus vs. M. nivale on cereal seeds (mostly wheat) harvested in Norway, is in agreement with studies in UK (Parry et al. 1995). Parry et al. suggested that higher natural occurrence of M. majus (vs. M. nivale) on seeds of cereals could be partly due to the higher proportion of M. majus isolates producing perithecia and thus, a relatively higher amount of M. majus spores spreading to the ear (Parry et al. 1995). The high frequency of M. nivale (99 %) vs. M. majus on grasses collected in Norway could indicate that M. nivale is more aggressive on certain grass species. Studies in our lab indeed point towards a higher aggressiveness of M. nivale vs. M. majus on perennial ryegrass at low temperature (2?C) (Hofgaard et al 2006). However, the high incidence of M. nivale on grass leaves could also be caused by differences in temperature preferences, saprophytic ability or ability to infect certain plant parts. Isolates of M. nivale display a higher in vitro growth rate compared to isolates of M. majus at 2?C (Hofgaard et al. 2006). In conclusion, the higher natural occurrence of M. nivale vs. M. majus on turf grasses and the relatively higher aggressiveness of M. nivale on perennial ryegrass could indicate that M. nivale somehow is better adapted to infect certain grass species.
Abstract
No abstract has been registered
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No abstract has been registered
Abstract
No abstract has been registered