| 1. |
- Librado, P., et al.
(författare)
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The origins and spread of domestic horses from the Western Eurasian steppes
- 2021
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 598, s. 634-640
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Tidskriftsartikel (refereegranskat)abstract
- Analysis of 273 ancient horse genomes reveals that modern domestic horses originated in the Western Eurasian steppes, especially the lower Volga-Don region. Domestication of horses fundamentally transformed long-range mobility and warfare(1). However, modern domesticated breeds do not descend from the earliest domestic horse lineage associated with archaeological evidence of bridling, milking and corralling(2-4) at Botai, Central Asia around 3500 bc(3). Other longstanding candidate regions for horse domestication, such as Iberia(5) and Anatolia(6), have also recently been challenged. Thus, the genetic, geographic and temporal origins of modern domestic horses have remained unknown. Here we pinpoint the Western Eurasian steppes, especially the lower Volga-Don region, as the homeland of modern domestic horses. Furthermore, we map the population changes accompanying domestication from 273 ancient horse genomes. This reveals that modern domestic horses ultimately replaced almost all other local populations as they expanded rapidly across Eurasia from about 2000 bc, synchronously with equestrian material culture, including Sintashta spoke-wheeled chariots. We find that equestrianism involved strong selection for critical locomotor and behavioural adaptations at the GSDMC and ZFPM1 genes. Our results reject the commonly held association(7) between horseback riding and the massive expansion of Yamnaya steppe pastoralists into Europe around 3000 bc(8,9) driving the spread of Indo-European languages(10). This contrasts with the scenario in Asia where Indo-Iranian languages, chariots and horses spread together, following the early second millennium bc Sintashta culture(11,12).
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| 2. |
- Walker, Anthony P, et al.
(författare)
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Horizon 2020 EuPRAXIA design study
- 2017
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Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 874:1
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Tidskriftsartikel (refereegranskat)abstract
- The Horizon 2020 Project EuPRAXIA ("European Plasma Research Accelerator with eXcellence In Applications") is preparing a conceptual design report of a highly compact and cost-effective European facility with multi-GeV electron beams using plasma as the acceleration medium. The accelerator facility will be based on a laser and/or a beam driven plasma acceleration approach and will be used for photon science, high-energy physics (HEP) detector tests, and other applications such as compact X-ray sources for medical imaging or material processing. EuPRAXIA started in November 2015 and will deliver the design report in October 2019. EuPRAXIA aims to be included on the ESFRI roadmap in 2020.
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| 3. |
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| 4. |
- Fages, A., et al.
(författare)
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Tracking Five Millennia of Horse Management with Extensive Ancient Genome Time Series
- 2019
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Ingår i: Cell. - : Elsevier BV. - 0092-8674. ; 177:6
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Tidskriftsartikel (refereegranskat)abstract
- Horse domestication revolutionized warfare and accelerated travel, trade, and the geographic expansion of languages. Here, we present the largest DNA time series for a non-human organism to date, including genome-scale data from 149 ancient animals and 129 ancient genomes (>= 1-fold coverage), 87 of which are new. This extensive dataset allows us to assess the modem legacy of past equestrian civilisations. We find that two extinct horse lineages existed during early domestication, one at the far western (Iberia) and the other at the far eastern range (Siberia) of Eurasia. None of these contributed significantly to modern diversity. We show that the influence of Persian-related horse lineages increased following the Islamic conquests in Europe and Asia. Multiple alleles associated with elite-racing, including at the MSTN "speed gene," only rose in popularity within the last millennium. Finally, the development of modem breeding impacted genetic diversity more dramatically than the previous millennia of human management.
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| 5. |
- Damgaard, P. D., et al.
(författare)
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The first horse herders and the impact of early Bronze Age steppe expansions into Asia
- 2018
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 360:6396
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Tidskriftsartikel (refereegranskat)abstract
- The Yamnaya expansions from the western steppe into Europe and Asia during the Early Bronze Age (similar to 3000 BCE) are believed to have brought with them Indo-European languages and possibly horse husbandry. We analyzed 74 ancient whole-genome sequences from across Inner Asia and Anatolia and show that the Botai people associated with the earliest horse husbandry derived from a hunter-gatherer population deeply diverged from the Yamnaya. Our results also suggest distinct migrations bringing West Eurasian ancestry into South Asia before and after, but not at the time of, Yamnaya culture. We find no evidence of steppe ancestry in Bronze Age Anatolia from when Indo-European languages are attested there. Thus, in contrast to Europe, Early Bronze Age Yamnaya-related migrations had limited direct genetic impact in Asia.
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| 6. |
- Muhlemann, B., et al.
(författare)
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Ancient hepatitis B viruses from the Bronze Age to the Medieval period
- 2018
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 557:7705, s. 418-423
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Tidskriftsartikel (refereegranskat)abstract
- Hepatitis B virus (HBV) is a major cause of human hepatitis. There is considerable uncertainty about the timescale of its evolution and its association with humans. Here we present 12 full or partial ancient HBV genomes that are between approximately 0.8 and 4.5 thousand years old. The ancient sequences group either within or in a sister relationship with extant human or other ape HBV clades. Generally, the genome properties follow those of modern HBV. The root of the HBV tree is projected to between 8.6 and 20.9 thousand years ago, and we estimate a substitution rate of 8.04 x 10(-6-)1.51 x 10(-5) nucleotide substitutions per site per year. In several cases, the geographical locations of the ancient genotypes do not match present-day distributions. Genotypes that today are typical of Africa and Asia, and a subgenotype from India, are shown to have an early Eurasian presence. The geographical and temporal patterns that we observe in ancient and modern HBV genotypes are compatible with well-documented human migrations during the Bronze and Iron Ages(1,2). We provide evidence for the creation of HBV genotype A via recombination, and for a long-term association of modern HBV genotypes with humans, including the discovery of a human genotype that is now extinct. These data expose a complexity of HBV evolution that is not evident when considering modern sequences alone.
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| 7. |
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| 8. |
- Kreibich, H., et al.
(författare)
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Adaptation to flood risk : results of international paired flood event studies
- 2017
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Ingår i: Earth's Future. - 2328-4277. ; 5:10, s. 953-965
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Tidskriftsartikel (refereegranskat)abstract
- As flood impacts are increasing in large parts of the world, understanding the primary drivers of changes in risk is essential for effective adaptation. To gain more knowledge on the basis of empirical case studies, we analyze eight paired floods, i.e. consecutive flood events that occurred in the same region, with the second flood causing significantly lower damage. These success stories of risk reduction were selected across different socio-economic and hydro-climatic contexts. The potential of societies to adapt is uncovered by describing triggered societal changes, as well as formal measures and spontaneous processes that reduced flood risk. This novel approach has the potential to build the basis for an international data collection and analysis effort to better understand and attribute changes in risk due to hydrological extremes in the framework of the IAHSs Panta Rhei initiative. Across all case studies, we find that lower damage caused by the second event was mainly due to significant reductions in vulnerability, e.g. via raised risk awareness, preparedness and improvements of organizational emergency management. Thus, vulnerability reduction plays an essential role for successful adaptation. Our work shows that there is a high potential to adapt, but there remains the challenge to stimulate measures that reduce vulnerability and risk in periods in which extreme events do not occur.
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| 9. |
- Larsson, Mats, 1976-
(författare)
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Spectroscopy of semiconductor quantum dots
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Quantum dots in the Si/Ge and InAs/GaAs materials systems are examined by means of photoluminescence. The spectroscopic study of Si/Ge quantum dots has demonstrated two different radiative recombination channels in the type II band alignment: The spatially direct transition inside the dot and the spatially indirect transition across the dot interface. Increased sample temperature results in a gradual transfer from the spatially indirect to the spatially direct recombination due to higher oscillator strength combined with the increased electron population inside the dot. In contrast to the spatially direct transition, the spatially indirect transition is shown to be sensitive to the carrier density due to the band bending at the Si/Ge interface. Due to an increased Si/Ge intermixing and hence reduced strain in the Si barrier, a reduction of the conduction band offset at increased growth temperatures is observed utilizing the different recombination channels as probes. The optical properties as derived from photoluminescence are correlated with the structural properties obtained by atomic force microscopy. Furthermore, by applying an electric field across the Si/Ge quantum dot structure, a reversed quantum confined Stark effect is demonstrated for the spatially indirect transition. By switching between the two different field directions, unique information on the growth related asymmetric strain profile derived at the through self-assembly of the quantum dots can be gained since corresponding information can not be obtained for type I systems.The studies of the InAs/GaAs quantum dots show that external electric and magnetic fields alter the in-plane carrier transport to the dots. The results obtained from the micro-photoluminescence exciton spectra of a single dot demonstrate a redistribution of the excitonic lines when a lateral electric field is applied. This fact exhibits an effective charge reconfiguration of the dot from a purely negative charge state to a neutral state, demonstrating that the number of electrons and holes are controlled by the electric field. The model proposed to explain the charge redistribution is based on an effective hole localization at the potential fluctuations of the wetting layer at low temperatures and low fields. Furthermore, it is demonstrated that the quantum dot photoluminescence signal is considerably increased (up to a factor of 4) depending on the magnitude of the external electric field. The experimental results also show that the internal field is altered by an additional infrared illumination of the sample. An applied magnetic field perpendicular to the quantum dot layer at low temperatures is found to enhance the carrier localization in the wetting layer and accordingly reduce the quantum dot photoluminescence intensity. At higher temperatures (>100K), an enhanced photoluminescence intensity is instead observed due to increased capture, localization, and recombination rate of the carriers in the quantum dots.
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