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Commons, sustainability, democratization : Action research and the basic renewal of society
- 2016
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Samlingsverk (redaktörskap) (övrigt vetenskapligt/konstnärligt)abstract
- This book presents theoretical discussions and practical examples of Action Research from Scandinavia, Latin America and Africa, primarily dealing with how to combine nature conservation and management with local democratic community development, seeing the renewal of Commons as a way to transcend the present dichotomy between these two dimensions
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- Hansen, Hans Peter, et al.
(författare)
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Introduction to part one
- 2016
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Annan publikation (övrigt vetenskapligt/konstnärligt)
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5. |
- Hansen, Hans Peter, et al.
(författare)
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Preface
- 2016
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Annan publikation (övrigt vetenskapligt/konstnärligt)
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- Kristensen, Peter L., et al.
(författare)
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Impact of the tcf7l2 genotype on risk of hypoglycaemia and glucagon secretion during hypoglycaemia
- 2016
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Ingår i: Endocrine Connections. - 2049-3614. ; 5:6, s. 53-60
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: In healthy carriers of the T allele of the transcription factor 7-like 2 (TCF7L2), fasting plasma glucagon concentrations are lower compared with those with the C allele. We hypothesised that presence of the T allele is associated with a diminished glucagon response during hypoglycaemia and a higher frequency of severe hypoglycaemia (SH) in type 1 diabetes (T1DM). Material and methods: This is a post hoc study of an earlier prospective observational study of SH and four mechanistic studies of physiological responses to hypoglycaemia. 269 patients with T1DM were followed in a one-year observational study. A log-linear negative binomial model was applied with events of SH as dependent variable and TCF7L2 alleles as explanatory variable. In four experimental studies including 65 people, TCF7L2 genotyping was done and plasma glucagon concentration during experimental hypoglycaemia was determined. Results: Incidences of SH were TT 0.54, TC 0.98 and CC 1.01 episodes per patient-year with no significant difference between groups. During experimental hypoglycaemia, the TCF7L2 polymorphism did not influence glucagon secretion. Discussion: Patients with T1DM carrying the T allele of the TCF7L2 polymorphism do not exhibit diminished glucagon response during hypoglycaemia and are not at increased risk of severe hypoglycaemia compared with carriers of the C allele.
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- López-Blanco, Efrén, et al.
(författare)
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Exchange of CO2 in Arctic tundra : Impacts of meteorological variations and biological disturbance
- 2017
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Ingår i: Biogeosciences. - : Copernicus GmbH. - 1726-4170 .- 1726-4189. ; 14:19, s. 4467-4483
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Tidskriftsartikel (refereegranskat)abstract
- An improvement in our process-based understanding of carbon (C) exchange in the Arctic and its climate sensitivity is critically needed for understanding the response of tundra ecosystems to a changing climate. In this context, we analysed the net ecosystem exchange (NEE) of CO2 in West Greenland tundra (64°N) across eight snow-free periods in 8 consecutive years, and characterized the key processes of net ecosystem exchange and its two main modulating components: gross primary production (GPP) and ecosystem respiration (Reco). Overall, the ecosystem acted as a consistent sink of CO2, accumulating g'30g dagger;Cg'2 on average (range of g'17 to g'41gdagger;Cg'2) during the years 2008-2015, except 2011 (source of 41gdagger;Cg'2), which was associated with a major pest outbreak. The results do not reveal a marked meteorological effect on the net CO2 uptake despite the high interannual variability in the timing of snowmelt and the start and duration of the growing season. The ranges in annual GPP (g'182 to g'316gdagger;Cg'2) and Reco (144 to 279gdagger;Cg'2) were > 5 fold larger than the range in NEE. Gross fluxes were also more variable (coefficients of variation are 3.6 and 4.1% respectively) than for NEE (0.7%). GPP and Reco were sensitive to insolation and temperature, and there was a tendency towards larger GPP and Reco during warmer and wetter years. The relative lack of sensitivity of NEE to meteorology was a result of the correlated response of GPP and Reco. During the snow-free season of the anomalous year of 2011, a biological disturbance related to a larvae outbreak reduced GPP more strongly than Reco. With continued warming temperatures and longer growing seasons, tundra systems will increase rates of C cycling. However, shifts in sink strength will likely be triggered by factors such as biological disturbances, events that will challenge our forecasting of C states.
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- López-Blanco, Efrén, et al.
(författare)
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Plant Traits are Key Determinants in Buffering the Meteorological Sensitivity of Net Carbon Exchanges of Arctic Tundra
- 2018
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Ingår i: Journal of Geophysical Research - Biogeosciences. - 2169-8953.
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Tidskriftsartikel (refereegranskat)abstract
- The climate sensitivity of carbon (C) cycling in Arctic terrestrial ecosystems is a major unknown in the Earth system. There is a lack of knowledge about the mechanisms that drive the interactions between photosynthesis, respiration, and changes in C stocks across full annual cycles in Arctic tundra. We use a calibrated and validated model (soil-plant-atmosphere; SPA) to estimate net ecosystem exchange (NEE), gross primary production (GPP), ecosystem respiration (Reco), and internal C processing across eight full years. SPA's carbon flux estimates are validated with observational data obtained from the Greenland Ecosystem Monitoring program in West Greenland tundra. Overall, the model explained 73%, 73%, and 50% of the variance in NEE, GPP, and Reco, respectively, and 85% of the plant greenness variation. Flux data highlighted the insensitivity of growing season NEE to interannual meteorological variability, due to compensatory responses of photosynthesis and ecosystem respiration. In this modelling study, we show that this NEE buffering is the case also for full annual cycles. We show through a sensitivity analysis that plant traits related to nitrogen are likely key determinants in the compensatory response, through simulated links to photosynthesis and plant respiration. Interestingly, we found a similar temperature sensitivity of the trait-flux couplings for GPP and Reco, suggesting that plant traits drive the stabilization of NEE. Further, model analysis indicated that wintertime periods decreased the C sink by 60%, mostly driven by litter heterotrophic respiration. This result emphasizes the importance of wintertime periods and allows a more comprehensive understanding of full annual C dynamics.
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- Pateraki, Irini, et al.
(författare)
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Total biosynthesis of the cyclic AMP booster for skolin from Coleus forskohlii
- 2017
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Ingår i: eLIFE. - : ELIFE SCIENCES PUBLICATIONS LTD. - 2050-084X. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- Forskolin is a unique structurally complex labdane-type diterpenoid used in the treatment of glaucoma and heart failure based on its activity as a cyclic AMP booster. Commercial production of forskolin relies exclusively on extraction from its only known natural source, the plant Coleus forskohlii, in which forskolin accumulates in the root cork. Here, we report the discovery of five cytochrome P450s and two acetyltransferases which catalyze a cascade of reactions converting the forskolin precursor 13R-manoyl oxide into forskolin and a diverse array of additional labdane-type diterpenoids. A minimal set of three P450s in combination with a single acetyl transferase was identified that catalyzes the conversion of 13R-manoyl oxide into forskolin as demonstrated by transient expression in Nicotiana benthamiana. The entire pathway for forskolin production from glucose encompassing expression of nine genes was stably integrated into Saccharomyces cerevisiae and afforded forskolin titers of 40 mg/L.
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- Pirk, Norbert, et al.
(författare)
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Toward a statistical description of methane emissions from arctic wetlands
- 2017
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Ingår i: Ambio: a Journal of Human Environment. - : Springer Science and Business Media LLC. - 0044-7447. ; 46, s. 70-80
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Tidskriftsartikel (refereegranskat)abstract
- Methane (CH4) emissions from arctic tundra typically follow relations with soil temperature and water table depth, but these process-based descriptions can be difficult to apply to areas where no measurements exist. We formulated a description of the broader temporal flux pattern in the growing season based on two distinct CH4 source components from slow and fast-turnover carbon. We used automatic closed chamber flux measurements from NE Greenland (74°N), W Greenland (64°N), and Svalbard (78°N) to identify and discuss these components. The temporal separation was well-suited in NE Greenland, where the hypothesized slow-turnover carbon peaked at a time significantly related to the timing of snowmelt. The temporally wider component from fast-turnover carbon dominated the emissions in W Greenland and Svalbard. Altogether, we found no dependence of the total seasonal CH4 budget to the timing of snowmelt, and warmer sites and years tended to yield higher CH4 emissions.
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