| 1. |
- Luyssaert, S., et al.
(författare)
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CO2 balance of boreal, temperate, and tropical forests derived from a global database
- 2007
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Ingår i: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 13:12, s. 2509-2537
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Forskningsöversikt (refereegranskat)abstract
- Terrestrial ecosystems sequester 2.1 Pg of atmospheric carbon annually. A large amount of the terrestrial sink is realized by forests. However, considerable uncertainties remain regarding the fate of this carbon over both short and long timescales. Relevant data to address these uncertainties are being collected at many sites around the world, but syntheses of these data are still sparse. To facilitate future synthesis activities, we have assembled a comprehensive global database for forest ecosystems, which includes carbon budget variables (fluxes and stocks), ecosystem traits (e.g. leaf area index, age), as well as ancillary site information such as management regime, climate, and soil characteristics. This publicly available database can be used to quantify global, regional or biome-specific carbon budgets; to re-examine established relationships; to test emerging hypotheses about ecosystem functioning [e.g. a constant net ecosystem production (NEP) to gross primary production (GPP) ratio]; and as benchmarks for model evaluations. In this paper, we present the first analysis of this database. We discuss the climatic influences on GPP, net primary production (NPP) and NEP and present the CO2 balances for boreal, temperate, and tropical forest biomes based on micrometeorological, ecophysiological, and biometric flux and inventory estimates. Globally, GPP of forests benefited from higher temperatures and precipitation whereas NPP saturated above either a threshold of 1500 mm precipitation or a mean annual temperature of 10 degrees C. The global pattern in NEP was insensitive to climate and is hypothesized to be mainly determined by nonclimatic conditions such as successional stage, management, site history, and site disturbance. In all biomes, closing the CO2 balance required the introduction of substantial biome-specific closure terms. Nonclosure was taken as an indication that respiratory processes, advection, and non-CO2 carbon fluxes are not presently being adequately accounted for.
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| 2. |
- Jacobsson, Lennart, et al.
(författare)
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Rheumatoid arthritis: what does it cost and what factors are driving those costs? Results of a survey in a community-derived population in Malmo, Sweden
- 2007
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Ingår i: Scandinavian Journal of Rheumatology. - : Informa UK Limited. - 1502-7732 .- 0300-9742. ; 36:3, s. 179-183
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Tidskriftsartikel (refereegranskat)abstract
- Objective: We sought to investigate the cost of living with rheumatoid arthritis (RA) and evaluate the influence of both demographics and specific disease characteristics on these costs. Methods: We used a population-based questionnaire to survey 895 patients living in the city of Malmo, Sweden, during 2002. Data were obtained on direct resource consumption, investments, informal care and work capacity, as well as utility, function and patients' assessment of disease severity and pain. Results: The survey was completed by 613 patients (68%). Their mean age was 66 years, 74% were female and the mean duration of disease was 16.7 years. The total mean annual cost per patient was 108 370 SEK (12 020 EUR). Direct costs represented 41% of that amount and were predominantly for drugs [141% of the participants were receiving treatment with tumour necrosis factor (TNF) blockers], community services and hospitalisation. Function measured with the Health Assessment Questionnaire (HAQ) was the main statistical predictor for all types of costs except sick leave, which was most strongly associated with patients' perception of global health. Conclusion: This is the first study in Sweden to include all costs incurred by a group representative of RA in the community. In comparison with previous studies, total costs had increased by more than 40%. Furthermore, direct costs were higher and constituted a great proportion of total costs because of more intensive treatments (i.e. the use of TNF blockers). Future comparisons will enable health economic evaluations on a community level.
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| 3. |
- Kobelt, G, et al.
(författare)
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Modelling the effect of function and disease activity on costs and quality of life in rheumatoid arthritis
- 2005
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Ingår i: Rheumatology. - : Oxford University Press (OUP). - 1462-0332 .- 1462-0324. ; 44:9, s. 1169-1175
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Tidskriftsartikel (refereegranskat)abstract
- Objective. When treatments with the potential to change the natural history of a disease are introduced, their longer-term effect on costs and quality of life (utility) has to be estimated using economic models. However, to remain useful tools, models must be updated when new information becomes available. Our earlier models in rheumatoid arthritis (RA) have been based on functional status, but it has recently been shown that disease activity might have an independent effect on utility. The objective of this study was to improve the model by incorporating the effect of a subjective measure of disease severity and activity (global VAS). Methods. A Markov model was constructed with five states according to functional status (HAQ), and each state was subdivided according to the VAS (< 40 and > 40). Disease development (transition probabilities between the states) was taken from a longitudinal cohort study of patients with early RA in Sweden. A recent population-based survey of 616 patients with RA provided data on costs and utilities. The model incorporates the full distribution of costs and utilities from the survey, and long-term projections are made using Monte Carlo simulation. Results. The global VAS had a highly significant effect on utilities independently of HAQ. For resource consumption, only HAQ was a significant predictor, with the exception of sick leave, which was correlated with the VAS but not with HAQ. Using the cohort distribution from the longitudinal study, expected mean costs per patient over 10 yr were 106 034 euros (s.d. 5091 euros) (1 euro = SEK 9.20) and the expected number of quality-adjusted life years (QALYs) was 5.08 (s.d. 0.09). Patients starting at HAQ < 0.6 but with consistently high VAS scores would have expected costs of 102 830 euros and 4.96 QALYs, while patients with low VAS scores would have costs of 81 603 euros and 6.01 QALYs. Conclusion. Our new model incorporates for the first time the effect of a subjective measure of disease severity and activity on both costs and utility, making it a sensitive tool to estimate the cost-effectiveness of disease-modifying treatments. New data on resource consumption indicate a shift to higher direct costs, particularly in early disease, and lower indirect costs in more advanced disease. The large size of the data sets used in this model reduces the uncertainty and makes estimates very stable.
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| 4. |
- Piao, Shilong, et al.
(författare)
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Net carbon dioxide losses of northern ecosystems in response to autumn warming
- 2008
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 451:7174, s. 3-49
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Tidskriftsartikel (refereegranskat)abstract
- The carbon balance of terrestrial ecosystems is particularly sensitive to climatic changes in autumn and spring(1-4), with spring and autumn temperatures over northern latitudes having risen by about 1.1 degrees C and 0.8 degrees C, respectively, over the past two decades(5). A simultaneous greening trend has also been observed, characterized by a longer growing season and greater photosynthetic activity(6,7). These observations have led to speculation that spring and autumn warming could enhance carbon sequestration and extend the period of net carbon uptake in the future(8). Here we analyse interannual variations in atmospheric carbon dioxide concentration data and ecosystem carbon dioxide fluxes. We find that atmospheric records from the past 20 years show a trend towards an earlier autumn- to- winter carbon dioxide build- up, suggesting a shorter net carbon uptake period. This trend cannot be explained by changes in atmospheric transport alone and, together with the ecosystem flux data, suggest increasing carbon losses in autumn. We use a process- based terrestrial biosphere model and satellite vegetation greenness index observations to investigate further the observed seasonal response of northern ecosystems to autumnal warming. We find that both photosynthesis and respiration increase during autumn warming, but the increase in respiration is greater. In contrast, warming increases photosynthesis more than respiration in spring. Our simulations and observations indicate that northern terrestrial ecosystems may currently lose carbon dioxide in response to autumn warming, with a sensitivity of about 0.2 PgC degrees C-1, offsetting 90% of the increased carbon dioxide uptake during spring. If future autumn warming occurs at a faster rate than in spring, the ability of northern ecosystems to sequester carbon may be diminished earlier than previously suggested(9,10).
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| 5. |
- Söderlin, Maria, et al.
(författare)
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Trends in medication and health-related quality of life in a population-based rheumatoid arthritis register in Malmo, Sweden
- 2007
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Ingår i: Rheumatology. - : Oxford University Press (OUP). - 1462-0332 .- 1462-0324. ; 46:8, s. 1355-1358
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Tidskriftsartikel (refereegranskat)abstract
- Objectives. To study trends in treatment, health status and health-related quality of life (HRQL) in two cross-sectional surveys over a 5-yr period and in an observational follow-up sub-cohort based on a population-based rheumatoid arthritis (RA) register in Malm6, Sweden. Material and methods. A continuously updated population-based RA register was established in Malm6 city in southern Sweden in 1997. Patient-administered questionnaires in 1997 and 2002 were used to collect information on demographics, medication and health status. Cross-sectional comparisons were made between 1997 and 2002. A longitudinal analysis was also performed in the RA patients participating in both surveys. Results. Increased proportions of patients were treated with disease-modifying anti-rheumatic drugs (DMARDs) (69 vs 52%), corticosteroids (30 vs 23%), methotrexate (52 vs 29%) and biologics (14 vs 0%) in 2002 compared with 1997. In the cross-sectional analysis, the visual analogue scores (VAS) for pain and general health and the short form 36 (SF-36) domains were slightly better in 2002 than in 1997. In the observational sub-cohort, patients treated with biologics improved significantly in several measures of health status, whereas those starting on methotrexate or undergoing other or no changes in DMARD therapy did not. Conclusions. In this population-based RA cohort, patients were more actively treated in 2002. Small improvements were seen in health status and these improvements were exclusively attributable to treatment with biologics.
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