排序方式： 共有10条查询结果，搜索用时 171 毫秒
1
1.
2.
3.
Scots pine stand establishment with special emphasis on uncertainty and cost-effectiveness,the case of northern Finland 总被引：1，自引：1，他引：0
The effect of uncertainty on the cost-effectiveness of alternative chains of stand establishment in northern Finland was examined.
The data were from a reforestation study of Scots pine (Pinus sylvestris L.) consisting of 288 sample plots, which were measured with respect to regeneration success. The study design included four
site-preparation methods (patch scarification, ploughing, prescribed burning and disk trenching) combined with three reforestation
methods (sowing, planting with containerized seedlings and planting with bare-rooted transplants). Initial reforestation density
was 2,500 spots or seedlings per hectare, and the regeneration success was modeled as probability with two thresholds, namely
500 and 1,100 saplings. On formerly spruce-dominated as well as pine-dominated sites the most cost-effective chain was ploughing
and planting with containerized seedlings, when threshold was 1,100 saplings per hectare. However, with threshold of 500 saplings
the best performer was ploughing and direct sowing on both sites. 相似文献
4.
Summary Data from two Swedish and one Finnish open-top chamber experiments were combined to investigate effects of ozone exposure
on potato (Solanum tuberosum L.) tuber content of starch, sucrose, fructose, glucose, malic, citric and ascorbic acids. The
glucose, fructose and malic acid concentrations showed strong negative correlations with ozone exposure, while citric acid,
consistently increased with ozone exposure. No ozone effects could be demonstrated on starch, sucrose or ascorbic acid concentrations.
It is discussed to what extent the changes found in potato tuber composition can be explained in terms of ozone effects on
tuber maturity. Ozone exposure was expressed as the accumulated exposure over a cut-off concentration of 40 nmol mol−1 (AOT40) and as the accumulated uptake of ozone over an ozone uptake rate threshold of 7 nmol m−2 s−1 (CUO 7). The difference in ability of the exposure indices to explain observed effects was small. 相似文献
5.
Mirja Ruohoniemi DVM Virpi Ryhänen Riitta-Mari Tulamo DVM PhD 《Veterinary radiology & ultrasound》1998,39(2):125-132
Radiographic findings in the navicular bone and distal interphalangeal joint as well as the ossification status of the collateral cartilages of the distal phalanx were evaluated in 100 Finnhorse cadaver forefeet. The most common shapes of the proximal articular margin of the navicular bone were convex and straight. Remodeling of the navicular bone was common, especially on the lateral extremity. No bony fragments were identified at the distal flexor margin even though this area appeared irregular in several feet. Several large, rounded or lollipop-shaped synovial invaginations were identified in only six feet. The thickness of the flexor cortex varied considerably, and the corticomedullary junction was uni- or bilaterally indistinct in nine feet. The shape of the sagittal ridge of the flexor cortex was commonly flat but varied. It appeared locally irregular or indistinct in 17 feet, but changes elsewhere along the flexor cortex were rare. Osteophytosis on the dorsal and palmar margins of the distal interphalangeal joint and entheseophytosis on the dorsal aspect of the middle phalanx and on the extensor process of the distal phalanx were common. "Possibly significant" ossification of the collateral cartilages (high side-bones or separate centers of ossification) was present in 36 feet; all grades of ossification in the proximal/ palmaroproximal direction as well as palmar ossification were seen. A statistically significant relationship was found between entheseophytosis on the proximal flexor margin of the navicular bone and "possibly significant" ossification. Osteophytosis on the palmarodistal margin of the middle phalanx was more common in feet with a relatively long distal phalanx, suggestive of palmar ossification. Radiographic changes in the navicular bone or in the distal interphalangeal joint did not otherwise appear to be associated with ossification of the collateral cartilages of the distal phalanx in Finnhorses. 相似文献
6.
Vierimaa O Georgitsi M Lehtonen R Vahteristo P Kokko A Raitila A Tuppurainen K Ebeling TM Salmela PI Paschke R Gündogdu S De Menis E Mäkinen MJ Launonen V Karhu A Aaltonen LA 《Science (New York, N.Y.)》2006,312(5777):1228-1230
Pituitary adenomas are common in the general population, and understanding their molecular basis is of great interest. Combining chip-based technologies with genealogy data, we identified germline mutations in the aryl hydrocarbon receptor interacting protein (AIP) gene in individuals with pituitary adenoma predisposition (PAP). AIP acts in cytoplasmic retention of the latent form of the aryl hydrocarbon receptor and also has other functions. In a population-based series from Northern Finland, two AIP mutations account for 16% of all patients diagnosed with pituitary adenomas secreting growth hormone and for 40% of the subset of patients who were diagnosed when they were younger than 35 years of age. Typically, PAP patients do not display a strong family history of pituitary adenoma; thus, AIP is an example of a low-penetrance tumor susceptibility gene. 相似文献
7.
The dry and wet deposition of N and S compounds to the Baltic Sea Basin were assessed using daily concentration measurements of air and precipitation concentrations, and actual meteorological data on precipitation, daily wind speed and wind direction, as well as the buoyant fluxes at the air- sea interface. The data cover the period 1980–86. Both concentrations and deposition levels show distinct south-north gradients and strong seasonal variability. Dry deposition is an important contribution in the case of S (25 to 80%) but is less significant for the N compounds (10 to 30%). The contribution of particles to dry deposition is negligible for S, equivalent to the gaseous contribution for oxidized N and about 10 to 20% for reduced nitrogen compounds. The obtained total annual deposition of about 1.4 to 1.8 g(S) m?2 for the S compounds, and 1 g(N) m?2 for the N compounds are comparable with, but on the upper side of, previous empirical and model estimates. 相似文献
8.
Jaana Laurila Virpi Ahola Ari Lehtinen Tiina Joutsjoki Asko Hannukkala Anne Rahkonen Minna Pirhonen 《European journal of plant pathology / European Foundation for Plant Pathology》2008,122(2):213-225
Plant pathogenic enterobacteria in the genera Pectobacterium and Dickeya (formerly classified as Erwinia) were isolated from diseased potato stems and tubers. The isolated bacteria were identified as P. atrosepticum, P. carotovorum and pathogens in the genus Dickeya with PCR tests. Furthermore, Dickeya strains were isolated from river water samples throughout the country. Phylogenetic analysis with 16S-23S rDNA intergenic
spacer sequences suggested that the Dickeya strains could be divided into three groups, two of which were isolated from potato samples. Phylogenetic analysis with 16S
rDNA sequences and growth at 39°C suggested that one of the groups corresponds to D. dianthicola, a quarantine pathogen in greenhouse cultivation of ornamentals, while two of the groups did not clearly resemble any of
the previously characterised Dickeya species. Field trials with the strains indicated that D. dianthicola-like strains isolated from river samples caused the highest incidence of rotting and necrosis of potato stems, but some of
the Dickeya strains isolated from potato samples also caused symptoms. The results showed that although P. atrosepticum is still the major cause of blackleg in Finland, virulent Dickeya strains were commonly present in potato stocks and rivers. This is the first report suggesting that Dickeya, originally known as a pathogen in tropical and warm climates, may cause diseases in potato in northern Europe. 相似文献
9.
Kärnä Olli-Matti Heino Jani Laamanen Tiina Jyrkänkallio-Mikkola Jenny Pajunen Virpi Soininen Janne Tolonen Kimmo T. Tukiainen Helena Hjort Jan 《Landscape Ecology》2019,34(10):2469-2485
Context
One approach to maintain the resilience of biotic communities is to protect the variability of abiotic characteristics of Earth’s surface, i.e. geodiversity. In terrestrial environments, the relationship between geodiversity and biodiversity is well recognized. In streams, the abiotic properties of upstream catchments influence stream communities, but the relationships between catchment geodiversity and aquatic biodiversity have not been previously tested.
ObjectivesThe aim was to compare the effects of local environmental and catchment variables on stream biodiversity. We specifically explored the usefulness of catchment geodiversity in explaining the species richness on stream macroinvertebrate, diatom and bacterial communities.
MethodsWe used 3 geodiversity variables, 2 land use variables and 4 local habitat variables to examine species richness variation across 88 stream sites in western Finland. We used boosted regression trees to explore the effects of geodiversity and other variables on biodiversity.
ResultsWe detected a clear effect of catchment geodiversity on species richness, although the traditional local habitat and land use variables were the strongest predictors. Especially soil-type richness appeared as an important factor for species richness. While variables related to stream size were the most important for macroinvertebrate richness and partly for bacterial richness, the importance of water chemistry and land use for diatom richness was notable.
ConclusionsIn addition to traditional environmental variables, geodiversity may affect species richness variation in streams, for example through changes in water chemistry. Geodiversity information could be used as a proxy for predicting stream species richness and offers a supplementary tool for conservation efforts.
相似文献10.
1