| 1. |
- Rosser, Z H, et al.
(författare)
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Y-chromosomal diversity in Europe is clinal and influenced primarily by geography, rather than by language.
- 2000
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Ingår i: American Journal of Human Genetics. - : Elsevier BV. - 0002-9297 .- 1537-6605. ; 67:6, s. 1526-43
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Tidskriftsartikel (refereegranskat)abstract
- Clinal patterns of autosomal genetic diversity within Europe have been interpreted in previous studies in terms of a Neolithic demic diffusion model for the spread of agriculture; in contrast, studies using mtDNA have traced many founding lineages to the Paleolithic and have not shown strongly clinal variation. We have used 11 human Y-chromosomal biallelic polymorphisms, defining 10 haplogroups, to analyze a sample of 3,616 Y chromosomes belonging to 47 European and circum-European populations. Patterns of geographic differentiation are highly nonrandom, and, when they are assessed using spatial autocorrelation analysis, they show significant clines for five of six haplogroups analyzed. Clines for two haplogroups, representing 45% of the chromosomes, are continentwide and consistent with the demic diffusion hypothesis. Clines for three other haplogroups each have different foci and are more regionally restricted and are likely to reflect distinct population movements, including one from north of the Black Sea. Principal-components analysis suggests that populations are related primarily on the basis of geography, rather than on the basis of linguistic affinity. This is confirmed in Mantel tests, which show a strong and highly significant partial correlation between genetics and geography but a low, nonsignificant partial correlation between genetics and language. Genetic-barrier analysis also indicates the primacy of geography in the shaping of patterns of variation. These patterns retain a strong signal of expansion from the Near East but also suggest that the demographic history of Europe has been complex and influenced by other major population movements, as well as by linguistic and geographic heterogeneities and the effects of drift.
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| 3. |
- Engelmark, O., et al.
(författare)
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Ecological effects and management aspects of an exotic tree species : the case of lodgepole pine in Sweden
- 2001
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Ingår i: Forest Ecology and Management. - 0378-1127 .- 1872-7042. ; 141:02-jan, s. 3-13
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Tidskriftsartikel (refereegranskat)abstract
- The North American tree Pinus contorta var, latifolia was experimentally introduced in Sweden already in the 1920s, and has been used in Swedish forestry on a large scale since the 1970s. These plantations now cover 565,000 ha, mainly in the northern area. In this paper we summarize and discuss existing ecological knowledge of this species introduction. With regard to longterm sustainability we suggest management means to minimize harmful effects of the introduction on ecosystems. These include aspects of self dispersal, pests, ecosystem and landscape structures, and also ecological processes and biodiversity. We also focus on observed and possible interactions in the ecosystems. As Pinus contorta seeds are disseminated and trees regenerated outside initial plantations, this may have future bearings on biodiversity. We suggest a strategy which takes account of the uncertainty in predicting future ecological effects. The strategy includes areal restrictions and zones without Pinus contorta, but also to set up a monitoring program. Observations of adverse effects from the plantations would then give the possibility to adjust P. contorta management.
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| 4. |
- Sala, O E, et al.
(författare)
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Biodiversity - Global biodiversity scenarios for the year 2100
- 2000
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 1095-9203 .- 0036-8075. ; 287:5459, s. 1770-1774
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Tidskriftsartikel (refereegranskat)abstract
- Scenarios of changes in biodiversity for the year 2100 can now be developed based on scenarios of changes in atmospheric carbon dioxide, climate, vegetation, and Land use and the known sensitivity of biodiversity to these changes. This study identified a ranking of the importance of drivers of change, a ranking of the biomes with respect to expected changes, and the major sources of uncertainties. For terrestrial ecosystems, land-use change probably wilt have the largest effect, followed by climate change, nitrogen deposition, biotic exchange, and elevated carbon dioxide concentration. For freshwater ecosystems, biotic exchange is much more important. Mediterranean climate and grassland ecosystems likely will experience the greatest proportional change in biodiversity because of the substantial influence of all drivers of biodiversity change. Northern temperate ecosystems are estimated to experience the least biodiversity change because major land-use change has already occurred. Plausible changes in biodiversity in other biomes depend on interactions among the causes of biodiversity change. These interactions represent one of the largest uncertainties in projections of future biodiversity change.
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| 5. |
- Sitch, S, et al.
(författare)
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Evaluation of ecosystem dynamics, plant geography and terrestrial carbon cycling in the LPJ dynamic global vegetation model
- 2003
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Ingår i: Global Change Biology. - : Wiley. - 1354-1013. ; 9:2, s. 161-185
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Tidskriftsartikel (refereegranskat)abstract
- The Lund-Potsdam-Jena Dynamic Global Vegetation Model (LPJ) combines process-based, large-scale representations of terrestrial vegetation dynamics and land-atmosphere carbon and water exchanges in a modular framework. Features include feedback through canopy conductance between photosynthesis and transpiration and interactive coupling between these 'fast' processes and other ecosystem processes including resource competition, tissue turnover, population dynamics, soil organic matter and litter dynamics and fire disturbance. Ten plants functional types (PFTs) are differentiated by physiological, morphological, phenological, bioclimatic and fire-response attributes. Resource competition and differential responses to fire between PFTs influence their relative fractional cover from year to year. Photosynthesis, evapotranspiration and soil water dynamics are modelled on a daily time step, while vegetation structure and PFT population densities are updated annually. Simulations have been made over the industrial period both for specific sites where field measurements were available for model evaluation, and globally on a 0.5degrees x 0.5degrees grid. Modelled vegetation patterns are consistent with observations, including remotely sensed vegetation structure and phenology. Seasonal cycles of net ecosystem exchange and soil moisture compare well with local measurements. Global carbon exchange fields used as input to an atmospheric tracer transport model (TM2) provided a good fit to observed seasonal cycles of CO2 concentration at all latitudes. Simulated inter-annual variability of the global terrestrial carbon balance is in phase with and comparable in amplitude to observed variability in the growth rate of atmospheric CO2 . Global terrestrial carbon and water cycle parameters (pool sizes and fluxes) lie within their accepted ranges. The model is being used to study past, present and future terrestrial ecosystem dynamics, biochemical and biophysical interactions between ecosystems and the atmosphere, and as a component of coupled Earth system models.
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| 6. |
- Borgstrom, F, et al.
(författare)
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Cost effectiveness of raloxifene in the treatment of osteoporosis in Sweden - An economic evaluation based on the MORE study
- 2004
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Ingår i: PharmacoEconomics. - : Adis Data Information BV.. - 1179-2027 .- 1170-7690. ; 22:17, s. 1153-1165
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Tidskriftsartikel (refereegranskat)abstract
- Background: The Multiple Outcomes of Raloxifene Evaluation (MORE) study showed that treatment with raloxifene reduces the risk of vertebral fracture and breast cancer in postmenopausal women with osteoporosis. Objective: Based on the MORE study the aim of the present study was to assess the cost effectiveness of raloxifene (compared with no treatment) for the treatment of osteoporosis in postmenopausal women in Sweden. Design: A revised version of a previously developed computer simulation model was used. The impact of the risk-reducing effect of raloxifene on vertebral fractures and breast cancer on cost effectiveness was analysed using a clinical and a morphometric definition of vertebral fracture. Benefits of raloxifene treatment were measured in quality-adjusted life-years (QALYs) and life-years gained. The study estimated the cost effectiveness mainly from a healthcare perspective but the cost effectiveness taking a societal perspective was also analysed. Results: Intervention costs (in Swedish kronor [SEK] and euros [E], year 2001 values) in postmenopausal women with a relative risk of vertebral fracture of 2 were SEK372 000 (E40 000) SEK303 000 (E33 000) and SEK263 000 (E28 000) per QALY for women aged 60, 70 and 80 years, at start of treatment, respectively, when the clinical vertebral definition was used. The cost effectiveness using a clinical morphometric vertebral fracture definition was similar to the cost effectiveness using a clinical vertebral fracture definition. Conclusions: In relation to accepted threshold values for cost per QALY in Sweden, this model indicates, with its underlying assumptions and data that raloxifene (compared with no treatment) is cost effective for the treatment of postmenopausal women at an increased risk of vertebral fracture. from the Swedish healthcare and societal perspectives.
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