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Marjatta Kärkkäinen DVM Drmedvet Matti Mero DVM MD Pentti Nummi MSc Lauri Punto DVM MD 《Veterinary radiology & ultrasound》1991,32(2):71-74
Magnetic resonance (MR) imaging is a relatively new method of medical imaging. MR studies on the normal canine central nervous system were performed using a low field MR scanner. The regions of interest were the head, neck, and lumbar region. The MR findings in two patients with brain atrophy and cervical neck disc protrusion were also evaluated. Based on our findings it appears that low-field scanners will be satisfactory for use in veterinary diagnostic imaging. 相似文献
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Jyrki Hytönen Jussi Saramäki Pentti Niemistö 《Scandinavian Journal of Forest Research》2014,29(1):1-11
The growth, technical quality and nutritional status of pure and mixed silver birch (Betula pendula Roth) and downy birch (Betula pubescens Ehrh.) plantations were studied 21 and 22 years after planting on afforested organic soil arable land and on upland forest soil. In mixtures, 50% of both birch species was planted. Silver birch trees grew better, but had higher mortality than downy birch trees on both sites. Mortality of both species was highest, and the difference in their growth smallest, on organic soil. In pure stands on organic soil, downy birch dominant height, diameter and mean volume were 96%, 92% and 82% of those of silver birch and on mineral soil 87%, 84% and 60%, correspondingly. On mineral soil, silver birch had a higher mean annual increment (MAI) (5.8 m3 ha?1a?1) than downy birch (3.9 m3 ha?1a?1), but on organic soil the MAI of both species was similar (3.3–3.4 m3 ha?1 a?1). Planting birches in mixture did not affect the growth of the trees on organic soil. On mineral soil, the mean diameter and mean volume of silver birch trees were higher in mixed than in pure plantations. The technical stem quality of both tree species was low. On mineral soils, pure silver birch is more productive than mixture, but on peat soil the higher growth of silver birch could contribute to increased productivity and downy birch would ensure sufficient survival for future timber production. 相似文献
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Annemari Kytömaa Sirpa Nieminen Pentti Thuneberg Heikki Haapala Pekka Nuorteva 《Water, air, and soil pollution》1995,81(3-4):401-409
Atomic absorption analyses were performed on an epiphytic lichenHypogymnia physodes growing at different distances from a sulphite-cellulose and paper plant in Mänttä, southern Finland. Lichen samples were taken from the bark of pine, birch and spruce. The mean Al-content of the lichen was 3-fold and 7.5-fold higher than those in other studies in southern and northern Finland. The accumulation of Al mainly orginated from the dust emission of the pulp and paper mill and its power plant which were the biggest single source of dust pollutants in Finland. Road dust and other local sources also increase Al-content of the lichens. Fe-concentrations ofHphysodes correlated with those of Al. Hg- and Cu-levels were also slightly elevated. Zn was at about the same and Cd at an even lower level than afore mentioned background values. With Zn, the contents were higher in lichens growing on birch than on coniferous trees. 相似文献
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Eero Jutila Erkki Jokikokko Irma Kallio-Nyberg Irma Saloniemi Pentti Pasanen 《Fisheries Research》2003,60(2-3):333-343
The effect of origin, smolt size and year of release on the sea migration pattern of Atlantic salmon (Salmo salar L.) in the Baltic Sea was examined by tagging experiments conducted in 1991–1993 on wild and reared smolts of the Simojoki river salmon stock. The tag recovery data analysed by log-linear models revealed significant differences in both spatial and temporal sea migrations between the wild and reared salmon; the variation was attributed to the year of release and to the origin of the fish. Grilse accounted for the majority of reared returners (76%) but for a smaller proportion (46%) of the wild fish. The effect of smolt size could be studied only in the smolt groups tagged in 1991. Wild fish were more frequently (71%) caught in the Baltic Main Basin than were reared fish (51%) during their second sea year, and the size variation between wild and reared smolts did not explain the recovery site. No such differences in spatial distribution were found during the third sea year. The tagging place (hatchery/trap) of the reared fish did not affect their later sea migration. The differences in sea migration patterns suggest that the wild salmon are more vulnerable to the intensive salmon fishery in the Baltic Main Basin than are reared fish. 相似文献
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