Recreational anglers as citizen scientists can provide data to estimate population size of pike,Esox lucius     

Konrad Karlsson  Elina Kari 《Fisheries Management and Ecology》2020,27(4):367-380

Catch‐per‐unit‐effort is often used as an approximation of population size. However, for the management and conservation of populations, information about the number of individuals is fundamental. Pike, Esox lucius L., is a popular fish species for recreational anglers. In this study, data in the form of journal keeping by anglers were used: date; place; and photographs of the captured fish; pike were identified based on their natural markings in combination with length measurements. The data were analysed by spatial capture–recapture (SCR) models. Results showed that a small and densely vegetated lake (6.7 ha) in south‐eastern Sweden had a population size of 91 (±22 SE) pike ≥60 cm. On one occasion, 10 individuals were caught, that is 11.1% of the population, highlighting that angling may potentially have a substantial impact on the population size. Hopefully, this study can inspire angler–manager collaborations for conservation of fish stocks.  相似文献   

Forest discourses and the role of planning-related perspectives: the case of Sweden     

Emmeline Laszlo Ambjörnsson  Svante Karlsson 《Scandinavian Journal of Forest Research》2016,31(1):111-118

Forest use in Sweden may be seen as constituting an essentially conflicted area, in which a number of actors position themselves. Based on a review of policy documents, this study reviews discourses on forest amongst major organisational actors between 2001 and 2011, with the aim of discussing the ways in which discourse may have changed following increasing criticism of the previously dominating production paradigm during the period. The study also discusses the ways in which forest discourses at present may also exclude areas that are relevant to forest planning. Results illustrates the continuous role of, on the one hand, production and private ownership discourses among the forest industry, and, on the other, conservation and public access discourses, among environmental and other NGOs. Large differences thus continue to exist despite the double aim towards production and protection in Swedish forest law. Areas that are not directly related to this nexus although related to land use at large, such as municipal planning, on the other hand, are largely absent from discourse even if, for instance, shore planning and wind power issues that are related to municipal planning are taken up.  相似文献   

Variation in growth of Heterobasidion annosum among clones of Picea abies incubated for different periods of time     

Swedjemark  Stenlid  Karlsson 《Forest Pathology》2001,31(3):163-175

Thirty‐seven 4‐year‐old clones of Picea abies were inoculated with one isolate of the S intersterility group of Heterobasidion annosum in a greenhouse. The dehardened cuttings were organized in three different groups with four to six ramets in each group. All groups were inoculated on the same day shortly after shoot elongation. The groups were sampled for H. annosum growth after 34 (group 1), 83 (group 2) and 182 days (group 3), respectively. Measured parameters were cutting height and diameter, vigour index of the cuttings, infection incidence, mortality rate and fungal growth in the stem. The height of the cuttings was almost constant during the 6 months of incubation, whereas the diameter increased by about 10% during the same period. The proportion of living cuttings containing H. annosum decreased with time (99.5, 93 and 67% infection in groups 1, 2 and 3, respectively) and differed significantly among clones in group 3. Mortality rate increased with time (0.5, 22 and 37% mortality in groups 1, 2 and 3, respectively) and differed significantly among clones in groups 2 and 3; the same clones being most susceptible for both times. Mean fungal growth into the wood was significantly different among groups and among clones within each group. The ranking position for fungal growth was similar in the three groups. The results indicate that frequency of infection success, mortality rate and fungal growth are clone‐dependent factors. Broad sense heritability varied between 0.08 and 0.25 for fungal growth and lesion length at the three incubation periods. Infection success frequency was initially not different among clones but in the longer incubation periods there were significant differences among clones, indicating differences in resistance. Fungal growth in wood differed among separate host clones irrespectively of the length of inoculation period. The vigour of the cuttings seem to influence the length of fungal extension only in the initial stage of the infection.  相似文献   

Effect of partial replacement of oats with sugar beet pulp and maize oil on nutrient utilisation in horses.     

J E Lindberg  C P Karlsson 《Equine veterinary journal》2001,33(6):585-590

The objective of the present work was to assess the influence of partial replacement of oats with dried unmolassed sugar beet pulp (SBP) and/or maize oil on nutrient utilisation in horses fed a traditional hay and concentrate diet. The total tract digestibility of nutrients, urinary excretion and plasma parameters were studied in a 4 x 4 Latin-square design experiment with purebred Arabian geldings. Horses fed the SBP diets responded with a reduced (P<0.05) apparent digestibility of crude protein and feeding of maize oil resulted in an increased (P<0.05) apparent digestibility of crude fat. The apparent energy digestibility was unaffected by the replacement of oats with SBP, but increased (P<0.05) when maize oil replaced part of the oats. The urinary excretion of nitrogen increased (P<0.05) when maize oil replaced oats and the excretion of energy was higher (P<0.05) on the diets where oats were replaced by maize oil and SBP. There was a significant (P<0.05) effect across treatments of postprandial blood sampling time on plasma glucose and insulin concentrations. Also, plasma concentrations of glucose and insulin tended to be higher on the oats than on the SBP diets. In conclusion, the limited effects on the digestibility of nutrients and energy suggest that it should be possible to partially replace oats with maize oil and/or SBP in diets for horses without any impairing effects on the overall nutrient utilisation. However, the dietary-induced changes in the urinary excretion of energy and on plasma glucose and insulin levels, indicate a possible influence of dietary carbohydrate composition on nutrient utilisation at the organ level, which requires further study.  相似文献   

Metabolic and Hormonal Response to a Feed‐challenge Test in Lean and Overweight Dogs          下载免费PDF全文

J. Söder  S. Wernersson  R. Hagman  I. Karlsson  K. Malmlöf  K. Höglund 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2016,30(2):574-582

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Helicobacter pylori SabA adhesin in persistent infection and chronic inflammation     

Mahdavi J  Sondén B  Hurtig M  Olfat FO  Forsberg L  Roche N  Angstrom J  Larsson T  Teneberg S  Karlsson KA  Altraja S  Wadström T  Kersulyte D  Berg DE  Dubois A  Petersson C  Magnusson KE  Norberg T  Lindh F  Lundskog BB  Arnqvist A  Hammarström L  Borén T 《Science (New York, N.Y.)》2002,297(5581):573-578

Helicobacter pylori adherence in the human gastric mucosa involves specific bacterial adhesins and cognate host receptors. Here, we identify sialyl-dimeric-Lewis x glycosphingolipid as a receptor for H. pylori and show that H. pylori infection induced formation of sialyl-Lewis x antigens in gastric epithelium in humans and in a Rhesus monkey. The corresponding sialic acid-binding adhesin (SabA) was isolated with the "retagging" method, and the underlying sabA gene (JHP662/HP0725) was identified. The ability of many H. pylori strains to adhere to sialylated glycoconjugates expressed during chronic inflammation might thus contribute to virulence and the extraordinary chronicity of H. pylori infection.  相似文献   

Simulating site-specific nitrogen mineralization dynamics in a Swedish arable field     

Thord Karlsson  Sofia Delin  Thomas Kätterer  Kerstin Berglund  Olof Andrén 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(4):333-344

Abstract

The objective of this work was to test whether a dynamic soil C and N model using site-specific information improved estimates of apparent net N mineralization compared with regressions only based on static soil properties. This comparison was made using data from a 34-point sampling grid within a Swedish arable field during two growing seasons, using a simple carbon balance and nitrogen mineralization model (ICBM/N) for the dynamic approach. Three free model parameters were simultaneously optimized using non-linear regression to obtain the best model fit to the data from all grid points and both years. Calculated annual mean net mineralization (Nm_sim) matched the measured Nm mean exactly, and was 44 and 71 kg N ha^?1 for the two growing seasons 1999 and 2000, respectively. However, the variability in calculated Nm_sim values among the 34 grid points was smaller than that measured, and only a small proportion of the variation within a single year was explained by the model. Despite this, the model explained 56% of the total variation in Nm during the two growing seasons, mainly due to the good fit to the seasonal overall difference. Significant factors influencing net mineralization included the soil environment controlling mineralization, total N in soil organic matter and N in crop residues. Uncertainties in estimation of θ _fc and θ _wp (soil water content at saturation and wilting point) and the possible influence of unknown horizontal and vertical water flows made high-precision calculations of soil water content difficult. The precision and general applicability of the actual measurements thus set limits for estimating critical parameters, and the limitations of both the experimental design and the model are discussed. It is concluded that improvements in precision in sampling and analysis of data from the grid points are needed for more critical hypothesis testing.  相似文献   

Quantification of <Emphasis Type="Italic">Phytophthora pisi</Emphasis> DNA and RNA transcripts during <Emphasis Type="Italic">in planta</Emphasis> infection of pea     

Sara Hosseini  Magnus Karlsson  Dan Funck Jensen  Fredrik Heyman 《European journal of plant pathology / European Foundation for Plant Pathology》2012,132(3):455-468

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Genetic aspects of sheep parasitic diseases     

Karlsson LJ  Greeff JC 《Veterinary parasitology》2012,189(1):104-112

There is evidence of genetically determined host resistance mechanisms for most of the sheep parasites evaluated. The mechanisms vary; from no or reduced establishment, early expulsion, to suppression of parasites resulting in reduced size and fecundity. There is a need to integrate breeding for parasite resistance with the genetic improvement of production traits in farm animals, aiming for optimum solutions for potentially conflicting responses. Sustainable parasite control must be based on Integrated Parasite Management utilising an interdisciplinary approach.  相似文献   

A solid-phase fluorescent immunoassay for detecting canine or mink enteritis parvoviruses in faecal samples   总被引：2，自引：0，他引：2  

E Rivera  K A Karlsson 《Veterinary microbiology》1987,15(1-2):1-9

Mink enteritis virus (MEV) and canine parvovirus (CPV) were detected in faecal samples from experimentally or naturally infected minks and dogs, respectively, using antibody-coated polyacrylamide beads (immunobeads, IB) as the solid phase for immunofluorescence (IF) tests. The specificity and sensitivity of the immunobead assay (IBA) were studied by comparing it with an enzyme-linked immunoassay (ELISA), a haemagglutination (HA) test and an IF test using tissue cultures. The IBA was as sensitive as ELISA, but more sensitive than the HA test and the IF test. Furthermore, the use of IB as the matrix for the immunological reactions allows FITC- or enzyme-conjugated antibodies to be used as indicators of the reactions and a simultaneous investigation of several pathogenic agents.  相似文献