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Injections of sclerosing agents into the caudae of the epididymides of adult and prepubertal dogs induced a long-lasting and probably irreversible azoospermia. The technique is easy to do and inexpensive, does not seem to cause undesirable side effects, and appears suitable for large-scale sterilization programs in male dogs.  相似文献   
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Infection of early bovine embryos with bovine herpesvirus-1   总被引:1,自引:0,他引:1  
Recently hatched bovine embryos were exposed in vitro to 1 of 4 strains of bovine herpesvirus-1 to determine whether the viruses would replicate in these embryos and, if so, what pathologic consequences would ensue. Exposure to each of the viruses resulted in embryonic infection and death, and replication of the agents was demonstrated by electron microscopy and titration of progeny virus. There were no dramatic differences between virus strains in pathogenicity or in the ultrastructural pathologic findings of infection.  相似文献   
6.
In Southwest Alberta, beef cattle and wild elk (Cervus elaphus) have similar habitat preferences. Understanding their inter-species contact structure is important for assessing the risk of pathogen transmission between them. These spatio-temporal patterns of interactions are shaped, in part, by range management and environmental factors affecting elk distribution. In this study, resource selection modeling was used to identify factors influencing elk presence on cattle pasture and elk selection of foraging patches; furthermore, consequences for inter-species disease transmission were discussed.  相似文献   
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An empirical report outlines veterinary problems in Rocky Mountain Goats kept in climatic conditions of Central Europe. Described are therapeutic findings in the treatment of infections, parasitosis, disorders of the extremities, disturbances of reproduction, and injuries as well as haematological findings and experiences made during immobilization of Rocky Mountain Goats.  相似文献   
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Carrier-free electrophoresis was used to separate subpopulations of bovine alveolar macrophages according to their electrical surface charges. The electrophoretic mobility of the macrophages changed significantly as a function of the time of cultivation in vitro. After 20 h, three subgroups were identified which differed in their specific contents of lysosomal hydrolases, alpha-naphthyl acetate esterase, and alkaline phosphodiesterase. By comparing the findings with results from the literature it was concluded that the subgroups correspond to different stages of maturation and that the fraction moving fastest may be the most mature fraction. The results were not influenced by phagocytosis and the presence or absence of Ca2+.  相似文献   
10.

? Context

Ecological research and an effective forest management need accurate information on the structure of the forest canopy to understand the biochemical, physiological and biogeochemical processes within a forest.

? Research question

This paper reviews the currently available instruments for measuring the distribution of biomass within forest canopies. We compare the most well-established approaches and present the different measurable parameters. A special focus lies on the resolution of the obtained data.

? Results

It was found that only 3D laser scanners offer data with the resolution required by ecologists, private landholders, the forest industry and the public to detect trends in tree growth patterns and canopy interactions in all three spatial dimensions. But data validation, data analysis and parameter extraction are still under development, and the price of the instrument is quite high.

? Conclusion

Research should focus on the parameter extraction from terrestrial laser scanner data as this could allow the calculation of functional attributes for different sections of a canopy on a high spatial resolution. It could also help ecologists characterize the structure of forest stands in a quick and precise way.  相似文献   
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