| 1. |
- Abdalla, H., et al.
(författare)
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Revealing x-ray and gamma ray temporal and spectral similarities in the GRB 190829A afterglow
- 2021
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Ingår i: Science. - : American Association of Advancement in Science. - 0036-8075 .- 1095-9203. ; 372:6546, s. 1081-1085
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Tidskriftsartikel (refereegranskat)abstract
- Gamma-ray bursts (GRBs), which are bright flashes of gamma rays from extragalactic sources followed by fading afterglow emission, are associated with stellar core collapse events. We report the detection of very- high-energy (VHE) gamma rays from the afterglow of GRB 190829A, between 4 and 56 hours after the trigger, using the High Energy Stereoscopic System (H.E.S.S.). The low luminosity and redshift of GRB 190829A reduce both internal and external absorption, allowing determination of its intrinsic energy spectrum. Between energies of 0.18 and 3.3 tera-electron volts, this spectrum is described by a power law with photon index of 2.07 +/- 0.09, similar to the x-ray spectrum. The x-ray and VHE gamma- ray light curves also show similar decay profiles. These similar characteristics in the x-ray and gamma-ray bands challenge GRB afterglow emission scenarios.
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| 2. |
- Akbari, Parsa, et al.
(författare)
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Sequencing of 640,000 exomes identifies GPR75 variants associated with protection from obesity
- 2021
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 373:6550
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Tidskriftsartikel (refereegranskat)abstract
- Large-scale human exome sequencing can identify rare protein-coding variants with a large impact on complex traits such as body adiposity. We sequenced the exomes of 645,626 individuals from the United Kingdom, the United States, and Mexico and estimated associations of rare coding variants with body mass index (BMI). We identified 16 genes with an exome-wide significant association with BMI, including those encoding five brain-expressed G protein-coupled receptors (CALCR, MC4R, GIPR, GPR151, and GPR75). Protein-truncating variants in GPR75 were observed in ∼4/10,000 sequenced individuals and were associated with 1.8 kilograms per square meter lower BMI and 54% lower odds of obesity in the heterozygous state. Knock out of Gpr75 in mice resulted in resistance to weight gain and improved glycemic control in a high-fat diet model. Inhibition of GPR75 may provide a therapeutic strategy for obesity.
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| 3. |
- Andersson, ER
(författare)
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In the zone for liver proliferation
- 2021
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Ingår i: Science (New York, N.Y.). - : American Association for the Advancement of Science (AAAS). - 1095-9203 .- 0036-8075. ; 371:6532, s. 887-888
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Tidskriftsartikel (refereegranskat)abstract
- Distinct liver compartments contribute to hepatocyte homeostasis versus regeneration
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| 4. |
- Bahram, Mohammad
(författare)
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How mycorrhizal associations drive plant population and community biology
- 2020
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 367
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Forskningsöversikt (refereegranskat)abstract
- Mycorrhizal fungi provide plants with a range of benefits, including mineral nutrients and protection from stress and pathogens. Here we synthesize current information about how the presence and type of mycorrhizal association affect plant communities. We argue that mycorrhizal fungi regulate seedling establishment and species coexistence through stabilizing and equalizing mechanisms such as soil nutrient partitioning, feedback to soil antagonists, differential mycorrhizal benefits, and nutrient trade. Mycorrhizal fungi have strong effects on plant population and community biology, with mycorrhizal type-specific effects on seed dispersal, seedling establishment, and soil niche differentiation, as well as interspecific and intraspecific competition and hence plant diversity.
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| 5. |
- Bergström, Anders, et al.
(författare)
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Origins and genetic legacy of prehistoric dogs
- 2020
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 370:6516, s. 557-563
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Tidskriftsartikel (refereegranskat)abstract
- Dogs were the first domestic animal, but little is known about their population history and to what extent it was linked to humans. We sequenced 27 ancient dog genomes and found that all dogs share a common ancestry distinct from present-day wolves, with limited gene flow from wolves since domestication but substantial dog-to-wolf gene flow. By 11,000 years ago, at least five major ancestry lineages had diversified, demonstrating a deep genetic history of dogs during the Paleolithic. Coanalysis with human genomes reveals aspects of dog population history that mirror humans, including Levant-related ancestry in Africa and early agricultural Europe. Other aspects differ, including the impacts of steppe pastoralist expansions in West and East Eurasia and a near-complete turnover of Neolithic European dog ancestry.
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| 6. |
- Blennow, Kaj, 1958
(författare)
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Phenotyping Alzheimer's disease with blood tests
- 2021
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 373, s. 626-628
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Forskningsöversikt (refereegranskat)abstract
- Affordable and accessible tools could be used for screening and therapy monitoring
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| 7. |
- Britton, Tom, et al.
(författare)
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A mathematical model reveals the influence of population heterogeneity on herd immunity to SARS-CoV-2
- 2020
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 369:6505, s. 846-849
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Tidskriftsartikel (refereegranskat)abstract
- Despite various levels of preventive measures, in 2020, many countries have suffered severely from the coronavirus 2019 (COVID-19) pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus. Using a model, we show that population heterogeneity can affect disease-induced immunity considerably because the proportion of infected individuals in groups with the highest contact rates is greater than that in groups with low contact rates. We estimate that if R-0 = 2.5 in an age-structured community with mixing rates fitted to social activity, then the disease-induced herd immunity level can be similar to 43%, which is substantially less than the classical herd immunity level of 60% obtained through homogeneous immunization of the population. Our estimates should be interpreted as an illustration of how population heterogeneity affects herd immunity rather than as an exact value or even a best estimate.
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| 8. |
- Brunet, Jörg
(författare)
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Forest microclimate dynamics drive plant responses to warming
- 2020
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 368, s. 772-775
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Tidskriftsartikel (refereegranskat)abstract
- Climate warming is causing a shift in biological communities in favor of warm-affinity species (i.e., thermophilization). Species responses often lag behind climate warming, but the reasons for such lags remain largely unknown. Here, we analyzed multidecadal understory microclimate dynamics in European forests and show that thermophilization and the climatic lag in forest plant communities are primarily controlled by microclimate. Increasing tree canopy cover reduces warming rates inside forests, but loss of canopy cover leads to increased local heat that exacerbates the disequilibrium between community responses and climate change. Reciprocal effects between plants and microclimates are key to understanding the response of forest biodiversity and functioning to climate and land-use changes.
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| 9. |
- Brunet, Jörg
(författare)
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Response to Comment on "Forest microclimate dynamics drive plant responses to warming"
- 2020
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 370
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Tidskriftsartikel (refereegranskat)abstract
- Bertrand et al. question our interpretation about warming effects on the thermophilization in forest plant communities and propose an alternative way to analyze climatic debt. We show that microclimate warming is a better predictor than macroclimate warming for studying forest plant community responses to warming. Their additional analyses do not affect or change our interpretations and conclusions.
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| 10. |
- Brunet, Jörg
(författare)
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Response to Comment on "Forest microclimate dynamics drive plant responses to warming"
- 2020
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 370
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Tidskriftsartikel (refereegranskat)abstract
- Schall and Heinrichs question our interpretation that the climatic debt in understory plant communities is locally modulated by canopy buffering. However, our results clearly show that the discrepancy between microclimate warming rates and thermophilization rates is highest in forests where canopy cover was reduced, which suggests that the need for communities to respond to warming is highest in those forests.
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