Assessing the consequences of habitat fragmentation for two migratory salmonid fishes          下载免费PDF全文

Claudia Junge  Jon Museth  Kjetil Hindar  Morten Kraabøl  L. Asbjørn Vøllestad 《水产资源保护:海洋与淡水生态系统》2014,24(3):297-311

Barley callus: a model system for bioengineering of starch in cereals     

M Carciofi  A Blennow  MM Nielsen  PB Holm  KH Hebelstrup 《Plant methods》2012,8(1):36

ABSTRACT: BACKGROUND: Starch is the most important source of calories for human nutrition and the majority of it is produced by cereal farming. Starch is also used as a renewable raw material in a range of industrial sectors. It can be chemically modified to introduce new physicochemical properties. In this way starch is adapted to a variety of specific end-uses. Recombinant DNA technologies offers an alternative to starch industrial processing. The plant biosynthetic pathway can be manipulated to design starches with novel structure and improved technological properties. In the future this may reduce or eliminate the economical and environmental costs of industrial modification. Recently, many advances have been achieved to clarify the genetic mechanism that controls starch biosynthesis. Several genes involved in the synthesis and modification of complex carbohydrates in many organisms have been identified and cloned. This knowledge suggests a number of strategies and a series of candidate genes for genetic transformation of crops to generate new types of starch-based polymers. However transformation of cereals is a slow process and there is no easy model system available to test the efficiency of candidate genes in planta. RESULTS: We explored the possibility to use transgenic barley callus generated from immature embryo for a fast test of transgenic modification strategies of starch biosynthesis. We found that this callus contains 4 % (w/w dw) starch granules, which we could modify by generating fully transgenic calli by Agrobacterium-transformation. A Green Fluorescent Protein reporter protein tag was used to identify and propagate only fully transgenic callus explants. Around 1 -- 1.5 g dry weight of fully transgenic callus could be produced in 9 weeks. Callus starch granules were smaller than endosperm starch granules and contained less amylose. Similarly the expression profile of starch biosynthesis genes were slightly different in callus compared with developing endosperm. CONCLUSIONS: In this study we have developed an easy and rapid in planta model system for starch bioengineering in cereals. We suggest that this method can be used as a time-efficient model system for fast screening of candidate genes for the generation of modified starch or new types of carbohydrate polymers.  相似文献   

Integrated data analysis in the presence of emigration and mark loss     

Toby J. Reynolds Ph.D. Student  Ruth King  John Harwood  Morten Frederiksen  Michael P. Harris  Sarah Wanless 《Journal of Agricultural, Biological & Environmental Statistics》2009,14(4):411-431

Integrated data analyses are becoming increasingly common in studies of wild animal populations where two or more separate sources of data contain information about common parameters. These types of analyses provide robust parameter estimates which fully reflect all available information, as well as estimates of parameters that would be unidentifiable in a separate analysis. In this article we present an integrated Bayesian analysis of four long-term datasets (counts, two mark-recapture-recovery time series, and productivity) relating to a colony of common guillemots (Uria aalge) on the Isle of May, southeast Scotland. A complication when considering the dynamics of populations of this kind is the unobservable emigration of immature animals. In the analysis of mark-recapture-recovery data, the rate of emigration is frequently confounded with that of mark loss and it is only possible to estimate the product of these parameters. By combining all available data for the Isle of May guillemots in an integrated population model, we are able to estimate these parameters separately and thus obtain improved estimates of prerecruitment emigration.  相似文献   

A Test of Positive Association for Detecting Heterogeneity in Capture for Capture–Recapture Data     

Anita Jeyam  Rachel S. McCrea  Thomas Bregnballe  Morten Frederiksen  Roger Pradel 《Journal of Agricultural, Biological & Environmental Statistics》2018,23(1):1-19

The Cormack–Jolly–Seber (CJS) model assumes that all marked animals have equal recapture probabilities at each sampling occasion, but heterogeneity in capture often occurs and should be taken into account to avoid biases in parameter estimates. Although diagnostic tests are generally used to detect trap-dependence or transience and assess the overall fit of the model, heterogeneity in capture is not routinely tested for. In order to detect and identify this phenomenon in a CJS framework, we propose a test of positive association between previous and future encounters using Goodman–Kruskal’s gamma. This test is based solely on the raw capture histories and makes no assumption on model structure. The development of the test is motivated by a dataset of Sandwich terns (Thalasseus sandvicensis), and we use the test to formally show that they exhibit heterogeneity in capture. We use simulation to assess the performance of the test in the detection of heterogeneity in capture, compared to existing and corrected diagnostic goodness-of-fit tests, Leslie’s test of equal catchability and Carothers’ extension of the Leslie test. The test of positive association is easy to use and produces good results, demonstrating high power to detect heterogeneity in capture. We recommend using this new test prior to model fitting as the outcome will guide the model-building process and help draw more accurate biological conclusions. Supplementary materials accompanying this paper appear online.  相似文献   

Mortality,fecundity and development among bed bugs (Cimex lectularius) exposed to prolonged,intermediate cold stress          下载免费PDF全文

Bjørn A Rukke  Morten Hage  Anders Aak 《Pest management science》2017,73(5):838-843

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Manual geo-rectification to improve the spatial accuracy of ortho-mosaics based on images from consumer-grade unmanned aerial vehicles (UAVs)     

Azim  Saiful  Rasmussen  Jesper  Nielsen  Jon  Gislum  René  Laursen  Morten Stigaard  Christensen  Svend 《Precision Agriculture》2019,20(6):1199-1210

Precision Agriculture - The global spatial accuracy of ortho-mosaics based on images from consumer-grade unmanned aerial vehicles (UAVs) is relatively low. The use of ground control points (GCPs)...  相似文献   

Evaluation of skin erythema by use of chromametry and image analysis of digital photographs after intradermal administration of histamine in dogs     

Boysen L  Sørensen P  Larsen M  Serup J  Kristensen F 《American journal of veterinary research》2002,63(4):565-569

OBJECTIVE: To investigate whether the degree of erythema during an induced erythematous reaction, the histamine skin test reaction, can be assessed objectively by use of chromametry and image analysis of digital photographs. ANIMALS: 9 pet dogs (6 Golden Retrievers and 3 yellow Labrador Retrievers). PROCEDURE: Histamine phosphate was injected intradermally, and erythema of the wheal reaction was evaluated during the hour that followed. This was done by use of clinical scores, chromametry, and image analysis of digital photographs. Method reproducibility was tested for visual evaluation of printouts of digital photographs and for image analysis of the same photographs. RESULTS: The coefficient of variation of the technically derived erythema values was < 10%. The reproducibility of image analysis was high and the range of agreement between observers narrow. Using chromametry, it was not possible to differentiate between various degrees of erythema intensity as visually perceived. In contrast, use of image analysis of digital photographs enabled discrimination of slight erythema from moderate and marked erythema. The dynamics of reaction measured by chromametry followed the clinical observation. CONCLUSIONS AND CLINICAL RELEVANCE: Chromametric values are comparable to those obtained by visual inspection. As the result of standardized conditions, chromametry is preferred over digital photography.  相似文献   

Characterization of avipoxviruses from wild birds in Norway   总被引：1，自引：0，他引：1       下载免费PDF全文

Simon Chioma Weli  Malachy Ifeanyi Okeke  Morten Tryland  ?ivind Nilssen    Terje Traavik 《Canadian journal of veterinary research》2004,68(2):140-145

Avipoxviruses from different geographic regions of the world have been characterized to study their genetic and biological properties, but so far, no such work has been performed on Norwegian isolates. Lesions suggestive of avian pox, found on a Norwegian wild sparrow (Passer domesticus) and wood pigeon (Palumbus palumbus), were obtained in 1972 and 1996, respectively. Histologically, these lesions were demonstrated to be characteristic of poxvirus infections and the poxvirus was observed using an electron microscope. The resulting viruses were propagated in chicken embryo fibroblast cells. Restriction fragment length polymorphism of genomes from 2 Norwegian isolates and fowl pox vaccine strain, generated by BamHI, revealed a high degree of heterogeneity among the isolates. The profiles of avipoxviruses isolated from wild birds were clearly distinct from each other and also to the fowl poxvirus strain. Furthermore, chickens experimentally infected with pigeon poxvirus had higher antibody titers and extensive lesions compared to other isolates. This may suggest that pigeon poxvirus is more virulent than the other isolates.  相似文献   

Porcine salmonellosis. II. Production of the generalized Shwartzman reaction by intravenous injections of disintegrated cells of salmonella cholerae-suis     

Knut Nordstoga  Morten Fjlstad 《Acta veterinaria Scandinavica》1970,11(3):370-379

Three pigs were given intravenous injections of disintegrated cells of Salmonella cholerae-suis. One of these pigs developed macroscopic bilateral renal cortical necrosis. Histologic examination revealed, besides total cortical parenchymal necrosis, also severe vascular injury, characterized with fibrinoid necrosis of the vessel walls and fibrin thrombi within their lumina. These findings were interpreted as a result of a generalized Shwartzman reaction, provoked by the action of bacterial endotoxin.  相似文献   

Regional differences in harvesting levels and wood-based employment in Norway     

Ståle Størdal  Kristian Lein  Morten Ørbeck  Svein Erik Hagen 《Small-Scale Forestry》2004,3(1):35-47

In this paper, a statistical framework based upon shift-share analysis is employed to analyse regional differences in Norway regarding changes in harvesting levels and number of full-time equivalent employees in wood processing. Changes in harvesting levels and employment differ between regions. A tendency found is that there has been a moderate centralisation in the period 1990–2000 with respect to harvesting levels. The analysis indicates that remote municipalities harvest relatively more in periods with a high harvesting intensity, while the harvesting level is more evenly distributed among the regions in other periods. There is, however, no clear picture whether there has been a centralisation or decentralisation regarding woodbased employment. Differences between regions may therefore be explained by structural factors, for example the degree to which firms in a particular region concentrate on production of bulky commodities or more customeroriented niche production.  相似文献