| 1. |
- Dawes, Melissa A., et al.
(författare)
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An alpine treeline in a carbon dioxide-rich world : synthesis of a nine-year free-air carbon dioxide enrichment study
- 2013
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Ingår i: Oecologia. - : Springer Science and Business Media LLC. - 0029-8549 .- 1432-1939. ; 171:3, s. 623-637
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Tidskriftsartikel (refereegranskat)abstract
- We evaluated the impacts of elevated CO2 in a treeline ecosystem in the Swiss Alps in a 9-year free-air CO2 enrichment (FACE) study. We present new data and synthesize plant and soil results from the entire experimental period. Light-saturated photosynthesis (A max) of ca. 35-year-old Larix decidua and Pinus uncinata was stimulated by elevated CO2 throughout the experiment. Slight down-regulation of photosynthesis in Pinus was consistent with starch accumulation in needle tissue. Above-ground growth responses differed between tree species, with a 33 % mean annual stimulation in Larix but no response in Pinus. Species-specific CO2 responses also occurred for abundant dwarf shrub species in the understorey, where Vaccinium myrtillus showed a sustained shoot growth enhancement (+11 %) that was not apparent for Vaccinium gaultherioides or Empetrum hermaphroditum. Below ground, CO2 enrichment did not stimulate fine root or mycorrhizal mycelium growth, but increased CO2 effluxes from the soil (+24 %) indicated that enhanced C assimilation was partially offset by greater respiratory losses. The dissolved organic C (DOC) concentration in soil solutions was consistently higher under elevated CO2 (+14 %), suggesting accelerated soil organic matter turnover. CO2 enrichment hardly affected the C–N balance in plants and soil, with unaltered soil total or mineral N concentrations and little impact on plant leaf N concentration or the stable N isotope ratio. Sustained differences in plant species growth responses suggest future shifts in species composition with atmospheric change. Consistently increased C fixation, soil respiration and DOC production over 9 years of CO2 enrichment provide clear evidence for accelerated C cycling with no apparent consequences on the N cycle in this treeline ecosystem.
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| 2. |
- Vogelezang, Suzanne, et al.
(författare)
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Novel loci for childhood body mass index and shared heritability with adult cardiometabolic traits.
- 2020
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Ingår i: PLoS genetics. - : Public Library of Science (PLoS). - 1553-7404. ; 16:10
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Tidskriftsartikel (refereegranskat)abstract
- The genetic background of childhood body mass index (BMI), and the extent to which the well-known associations of childhood BMI with adult diseases are explained by shared genetic factors, are largely unknown. We performed a genome-wide association study meta-analysis of BMI in 61,111 children aged between 2 and 10 years. Twenty-five independent loci reached genome-wide significance in the combined discovery and replication analyses. Two of these, located near NEDD4L and SLC45A3, have not previously been reported in relation to either childhood or adult BMI. Positive genetic correlations of childhood BMI with birth weight and adult BMI, waist-to-hip ratio, diastolic blood pressure and type 2 diabetes were detected (Rg ranging from 0.11 to 0.76, P-values <0.002). A negative genetic correlation of childhood BMI with age at menarche was observed. Our results suggest that the biological processes underlying childhood BMI largely, but not completely, overlap with those underlying adult BMI. The well-known observational associations of BMI in childhood with cardio-metabolic diseases in adulthood may reflect partial genetic overlap, but in light of previous evidence, it is also likely that they are explained through phenotypic continuity of BMI from childhood into adulthood.
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| 3. |
- Widell, Niklas, et al.
(författare)
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Gateway-based call admission in distributed object oriented systems
- 2000
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Ingår i: Proceedings fifteenth Nordic Teletraffic Seminar, NTS-15, Lund University, August 22-24, 2000.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Many applications in telecommunications will depend on distributed systems to provide enough capacity. In a distributed system a service is split up into a number of modules (often called objects) that can be placed at different nodes or processors in a network. A service can be seen as a number of invocations of the objects in a certain order. There are a number of performance problems which have to be solved. How shall objects be distributed on the nodes? How shall the load be distributed among the nodes for a given object distribution? How shall the distributed system be protected from temporary overload situations? In our paper we investigate these questions for distributed systems where requests for service arrive to a gateway from which they distributed to the nodes of the system. We assume that the object distribution is given and we concentrate on protecting the system using three different external load control mechanisms: Percent Thinning, Call Gapping and Tokens. Using simulations, we nd that Tokens provide the best system protection.
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| 4. |
- Ahlfors, Ulf, et al.
(författare)
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Overload control strategies in a multiprocessor system with distributed data
- 1995
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Ingår i: Proceedings of the 5th IEE Conference on Telecommunications, Brighton, UK, March 1995. - 0852966342 ; , s. 145-149
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Konferensbidrag (refereegranskat)abstract
- This paper addresses overload control issues for distributed control systems, i.e. multiprocessor systems, in telephone exchanges, signalling transfer points, service control points, home location registers, etc. Three different strategies for rejecting calls, due to severe overload conditions, are examined. The strategies differ in that they allow call rejection during different time epochs of the entire life time of the call. The optimal solution, i.e. the largest throughput, can only be obtained by a centrally placed overload control mechanism which collects data from all processors in the system
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| 5. |
- Bader, Martin K.-F., et al.
(författare)
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Less pronounced drought responses in ring-porous than in diffuse-porous temperate tree species
- 2022
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Ingår i: Agricultural and Forest Meteorology. - : Elsevier. - 0168-1923 .- 1873-2240. ; 327
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Tidskriftsartikel (refereegranskat)abstract
- Tree species differ in their physiological responses to drought, but the underlying causes are often unclear. Here we explored responses of radial growth to centennial drought events and sap flow (Fs) to seasonal drought in four mixed forests on either moist or drier sites in northwestern Switzerland. While the diffuse-porous species (Fagus sylvatica, Prunus avium, Tilia platyphyllos) showed marked growth reductions in 1976 and 2003, two known marker years for severe drought, growth of the two ring-porous species (Quercus petraea and Fraxinus excelsior) was less severely affected. During a dry early to midsummer, diffuse-porous species strongly reduced Fs at the two drier sites but not (or less so) at the two moister sites. Regardless of soil moisture availability, the deep- rooting, ring-porous trees invariably down-regulated Fs to 60–70% of their maxima in response to vapour pressure deficit (VPD) and maintained similar fluxes across sites, irrespective of upper soil moisture conditions. A generalised additive model of normalised Fs as a function of VPD and soil matric potential yielded a drought- sensitivity ranking of Fs led by the two insensitive ring-porous species followed by the diffuse-porous trees (ordered by increasing sensitivity: Fraxinus excelsior < Quercus petraea < Prunus avium < Acer pseudoplatanus < Fagus sylvatica < Tilia platyphyllos). In conclusion, ring-porous tree species exhibited stronger VPD-driven stomatal control over Fs, and tree-ring formation was less sensitive to severe drought than in their neighbouring diffuse-porous species. The Fs regulation explained the greater drought tolerance of the ring-porous trees.
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| 6. |
- Benzinou, Michael, et al.
(författare)
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Common nonsynonymous variants in PCSK1 confer risk of obesity.
- 2008
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Ingår i: Nature genetics. - : Springer Science and Business Media LLC. - 1546-1718 .- 1061-4036. ; 40:8, s. 943-5
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Tidskriftsartikel (refereegranskat)abstract
- Mutations in PCSK1 cause monogenic obesity. To assess the contribution of PCSK1 to polygenic obesity risk, we genotyped tag SNPs in a total of 13,659 individuals of European ancestry from eight independent case-control or family-based cohorts. The nonsynonymous variants rs6232, encoding N221D, and rs6234-rs6235, encoding the Q665E-S690T pair, were consistently associated with obesity in adults and children (P = 7.27 x 10(-8) and P = 2.31 x 10(-12), respectively). Functional analysis showed a significant impairment of the N221D-mutant PC1/3 protein catalytic activity.
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| 7. |
- Büntgen, Ulf, et al.
(författare)
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Limited capacity of tree growth to mitigate the global greenhouse effect under predicted warming
- 2019
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- It is generally accepted that animal heartbeat and lifespan are often inversely correlated, however, the relationship between productivity and longevity has not yet been described for trees growing under industrial and pre-industrial climates. Using 1768 annually resolved and absolutely dated ring width measurement series from living and dead conifers that grew in undisturbed, high-elevation sites in the Spanish Pyrenees and the Russian Altai over the past 2000 years, we test the hypothesis of grow fast-die young. We find maximum tree ages are significantly correlated with slow juvenile growth rates. We conclude, the interdependence between higher stem productivity, faster tree turnover, and shorter carbon residence time, reduces the capacity of forest ecosystems to store carbon under a climate warming-induced stimulation of tree growth at policy-relevant timescales.
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| 8. |
- Demichev, Vadim, et al.
(författare)
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A time-resolved proteomic and prognostic map of COVID-19
- 2021
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Ingår i: Cell Systems. - : Elsevier BV. - 2405-4712 .- 2405-4720. ; 12:8, s. 780-794.e7
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Tidskriftsartikel (refereegranskat)abstract
- COVID-19 is highly variable in its clinical presentation, ranging from asymptomatic infection to severe organ damage and death. We characterized the time-dependent progression of the disease in 139 COVID-19 inpatients by measuring 86 accredited diagnostic parameters, such as blood cell counts and enzyme activities, as well as untargeted plasma proteomes at 687 sampling points. We report an initial spike in a systemic inflammatory response, which is gradually alleviated and followed by a protein signature indicative of tissue repair, metabolic reconstitution, and immunomodulation. We identify prognostic marker signatures for devising risk-adapted treatment strategies and use machine learning to classify therapeutic needs. We show that the machine learning models based on the proteome are transferable to an independent cohort. Our study presents a map linking routinely used clinical diagnostic parameters to plasma proteomes and their dynamics in an infectious disease.
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| 9. |
- Dina, Christian, et al.
(författare)
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Variation in FTO contributes to childhood obesity and severe adult obesity.
- 2007
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Ingår i: Nature genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 39:6, s. 724-6
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Tidskriftsartikel (refereegranskat)abstract
- We identified a set of SNPs in the first intron of the FTO (fat mass and obesity associated) gene on chromosome 16q12.2 that is consistently strongly associated with early-onset and severe obesity in both adults and children of European ancestry with an experiment-wise P value of 1.67 x 10(-26) in 2,900 affected individuals and 5,100 controls. The at-risk haplotype yields a proportion of attributable risk of 22% for common obesity. We conclude that FTO contributes to human obesity and hence may be a target for subsequent functional analyses.
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| 10. |
- Felix, Janine F, et al.
(författare)
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Genome-wide association analysis identifies three new susceptibility loci for childhood body mass index.
- 2016
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Ingår i: Human molecular genetics. - : Oxford University Press (OUP). - 1460-2083 .- 0964-6906. ; 25:2, s. 389-403
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Tidskriftsartikel (refereegranskat)abstract
- A large number of genetic loci are associated with adult body mass index. However, the genetics of childhood body mass index are largely unknown. We performed a meta-analysis of genome-wide association studies of childhood body mass index, using sex- and age-adjusted standard deviation scores. We included 35 668 children from 20 studies in the discovery phase and 11 873 children from 13 studies in the replication phase. In total, 15 loci reached genome-wide significance (P-value < 5 × 10(-8)) in the joint discovery and replication analysis, of which 12 are previously identified loci in or close to ADCY3, GNPDA2, TMEM18, SEC16B, FAIM2, FTO, TFAP2B, TNNI3K, MC4R, GPR61, LMX1B and OLFM4 associated with adult body mass index or childhood obesity. We identified three novel loci: rs13253111 near ELP3, rs8092503 near RAB27B and rs13387838 near ADAM23. Per additional risk allele, body mass index increased 0.04 Standard Deviation Score (SDS) [Standard Error (SE) 0.007], 0.05 SDS (SE 0.008) and 0.14 SDS (SE 0.025), for rs13253111, rs8092503 and rs13387838, respectively. A genetic risk score combining all 15 SNPs showed that each additional average risk allele was associated with a 0.073 SDS (SE 0.011, P-value = 3.12 × 10(-10)) increase in childhood body mass index in a population of 1955 children. This risk score explained 2% of the variance in childhood body mass index. This study highlights the shared genetic background between childhood and adult body mass index and adds three novel loci. These loci likely represent age-related differences in strength of the associations with body mass index.
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