| 1. |
- Olalde, I., et al.
(författare)
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The Beaker phenomenon and the genomic transformation of northwest Europe
- 2018
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 555:7695, s. 190-196
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Tidskriftsartikel (refereegranskat)abstract
- From around 2750 to 2500 bc, Bell Beaker pottery became widespread across western and central Europe, before it disappeared between 2200 and 1800 bc. The forces that propelled its expansion are a matter of long-standing debate, and there is support for both cultural diffusion and migration having a role in this process. Here we present genome-wide data from 400 Neolithic, Copper Age and Bronze Age Europeans, including 226 individuals associated with Beaker-complex artefacts. We detected limited genetic affinity between Beaker-complex-associated individuals from Iberia and central Europe, and thus exclude migration as an important mechanism of spread between these two regions. However, migration had a key role in the further dissemination of the Beaker complex. We document this phenomenon most clearly in Britain, where the spread of the Beaker complex introduced high levels of steppe-related ancestry and was associated with the replacement of approximately 90% of Britain's gene pool within a few hundred years, continuing the east-to-west expansion that had brought steppe-related ancestry into central and northern Europe over the previous centuries.
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| 2. |
- 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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| 3. |
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| 4. |
- Schulz, S., et al.
(författare)
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Classical and cubic Rashba effect in the presence of in-plane 4f magnetism at the iridium silicide surface of the antiferromagnet GdIr2Si2
- 2021
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Ingår i: Physical Review B. - 2469-9950. ; 103:3
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Tidskriftsartikel (refereegranskat)abstract
- We present a combined experimental and theoretical study of the two-dimensional electron states at the iridium-silicide surface of the antiferromagnet GdIr2Si2 above and below the Néel temperature. Using angle-resolved photoemission spectroscopy (ARPES) we find a significant spin-orbit splitting of the surface states in the paramagnetic phase. By means of ab initio density-functional-theory (DFT) calculations we establish that the surface electron states that reside in the projected band gap around the M¯ point exhibit very different spin structures which are governed by the conventional and the cubic Rashba effect. The latter is reflected in a triple spin winding, i.e., the surface electron spin reveals three complete rotations upon moving once around the constant energy contours. Below the Néel temperature, our ARPES measurements show an intricate photoemission intensity picture characteristic of a complex magnetic domain structure. The orientation of the domains, however, can be clarified from a comparative analysis of the ARPES data and their DFT modeling. To characterize a single magnetic domain picture, we resort to the calculations and scrutinize the interplay of the Rashba spin-orbit coupling field with the in-plane exchange field, provided by the ferromagnetically ordered 4f moments of the near-surface Gd layer.
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| 5. |
- Patterson, Nick, et al.
(författare)
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Large-scale migration into Britain during the Middle to Late Bronze Age
- 2022
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Ingår i: Nature. - : Nature Publishing Group. - 0028-0836 .- 1476-4687. ; , s. 588-594
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Tidskriftsartikel (refereegranskat)abstract
- Present-day people from England and Wales harbour more ancestry derived from Early European Farmers (EEF) than people of the Early Bronze Age1. To understand this, we generated genome-wide data from 793 individuals, increasing data from the Middle to Late Bronze and Iron Age in Britain by 12-fold, and Western and Central Europe by 3.5-fold. Between 1000 and 875 BC, EEF ancestry increased in southern Britain (England and Wales) but not northern Britain (Scotland) due to incorporation of migrants who arrived at this time and over previous centuries, and who were genetically most similar to ancient individuals from France. These migrants contributed about half the ancestry of Iron Age people of England and Wales, thereby creating a plausible vector for the spread of early Celtic languages into Britain. These patterns are part of a broader trend of EEF ancestry becoming more similar across central and western Europe in the Middle to Late Bronze Age, coincident with archaeological evidence of intensified cultural exchange2-6. There was comparatively less gene flow from continental Europe during the Iron Age, and Britain's independent genetic trajectory is also reflected in the rise of the allele conferring lactase persistence to ~50% by this time compared to ~7% in central Europe where it rose rapidly in frequency only a millennium later. This suggests that dairy products were used in qualitatively different ways in Britain and in central Europe over this period.
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| 6. |
- Alonso-Sáez, Laura, et al.
(författare)
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Role for urea in nitrification by polar marine Archaea
- 2012
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 109:44, s. 17989-17994
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Tidskriftsartikel (refereegranskat)abstract
- Despite the high abundance of Archaea in the global ocean, their metabolism and biogeochemical roles remain largely unresolved. We investigated the population dynamics and metabolic activity of Thaumarchaeota in polar environments, where these microorganisms are particularly abundant and exhibit seasonal growth. Thaumarchaeota were more abundant in deep Arctic and Antarctic waters and grew throughout the winter at surface and deeper Arctic halocline waters. However, in situ single-cell activity measurements revealed a low activity of this group in the uptake of both leucine and bicarbonate (<5% Thaumarchaeota cells active), which is inconsistent with known heterotrophic and autotrophic thaumarchaeal lifestyles. These results suggested the existence of alternative sources of carbon and energy. Our analysis of an environmental metagenome from the Arctic winter revealed that Thaumarchaeota had pathways for ammonia oxidation and, unexpectedly, an abundance of genes involved in urea transport and degradation. Quantitative PCR analysis confirmed that most polar Thaumarchaeota had the potential to oxidize ammonia, and a large fraction of them had urease genes, enabling the use of urea to fuel nitrification. Thaumarchaeota from Arctic deep waters had a higher abundance of urease genes than those near the surface suggesting genetic differences between closely related archaeal populations. In situ measurements of urea uptake and concentration in Arctic waters showed that small-sized prokaryotes incorporated the carbon from urea, and the availability of urea was often higher than that of ammonium. Therefore, the degradation of urea may be a relevant pathway for Thaumarchaeota and other microorganisms exposed to the low-energy conditions of dark polar waters.
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| 9. |
- Lui, A. T. Y., et al.
(författare)
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Cluster observation of plasma flow reversal in the magnetotail during a substorm
- 2006
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Ingår i: Annales Geophysicae. - 0992-7689 .- 1432-0576. ; 24:7, s. 2005-2013
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Tidskriftsartikel (refereegranskat)abstract
- We investigate in detail a reversal of plasma flow from tailward to earthward detected by Cluster at the downstream distance of similar to 19 RE in the midnight sector of the magnetotail on 22 August 2001. This flow reversal was accompanied by a sign reversal of the B-z component and occurred during the late substorm expansion phase as revealed by simultaneous global view of auroral activity from IMAGE. We examine the associated Hall current system signature, current density, electric field, Lorentz force, and current dissipation/dynamo term, the last two parameters being new features that have not been studied previously for plasma flow reversals. It is found that (1) there was no clear quadrupole Hall current system signature organized by the flow reversal time, (2) the x-component of the Lorentz force did not change sign while the other two did, (3) the timing sequence of flow reversal from the Cluster configuration did not match tailward motion of a single plasma flow source, (4) the electric field was occasionally dawnward, producing a dynamo effect, and (5) the electric field was occasionally larger at the high-latitude plasma sheet than near the neutral sheet. These observations are consistent with the current disruption model for substorms in which these disturbances are due to shifting dominance of multiple current disruption sites and turbulence at the observing location.
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| 10. |
- Mende, Max, et al.
(författare)
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Strong Rashba Effect and Different f−d Hybridization Phenomena at the Surface of the Heavy-Fermion Superconductor CeIrIn 5
- 2022
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Ingår i: Advanced Electronic Materials. - : Wiley. - 2199-160X .- 2199-160X. ; 8:3
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Tidskriftsartikel (refereegranskat)abstract
- New temperature scales and remarkable differences from bulk properties have increasingly placed the surfaces of strongly correlated f materials into the focus of research activities. Applying first-principles calculations and angle-resolved photoelectron spectroscopy measurements, a strong Rashba effect and spin-split surface states at the CeIn surface of the heavy-fermion superconductor CeIrIn5 are revealed. The unveiled 4f-derived electron landscape is remarkably distinct for surface and bulk Ce implying the existence of novel temperature scales near the surface region in this material. These results show that ab initio calculations can reliably predict the unusual electronic and spin structure of surfaces of strongly correlated 4f systems where Rashba spin-orbit-coupling phenomena emerge. It is suggested that the structural blocks of such materials can be combined with magnetically active layers for engineering of novel nanostructural objects with appropriate substrates where the diversity of f-driven properties can be applied for the development of novel functionalities.
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| 11. |
- Nishimura, Y., et al.
(författare)
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Identifying the Driver of Pulsating Aurora
- 2010
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 330:6000, s. 81-84
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Tidskriftsartikel (refereegranskat)abstract
- Pulsating aurora, a spectacular emission that appears as blinking of the upper atmosphere in the polar regions, is known to be excited by modulated, downward-streaming electrons. Despite its distinctive feature, identifying the driver of the electron precipitation has been a long-standing problem. Using coordinated satellite and ground-based all-sky imager observations from the THEMIS mission, we provide direct evidence that a naturally occurring electromagnetic wave, lower-band chorus, can drive pulsating aurora. Because the waves at a given equatorial location in space correlate with a single pulsating auroral patch in the upper atmosphere, our findings can also be used to constrain magnetic field models with much higher accuracy than has previously been possible.
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| 12. |
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| 13. |
- Angelopoulos, V., et al.
(författare)
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First Results from the THEMIS Mission
- 2008
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Ingår i: Space Science Reviews. - : Springer Science and Business Media LLC. - 0038-6308 .- 1572-9672. ; 141:1-4, s. 453-476
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Forskningsöversikt (refereegranskat)abstract
- THEMIS was launched on February 17, 2007 to determine the trigger and large-scale evolution of substorms. During the first seven months of the mission the five satellites coasted near their injection orbit to avoid differential precession in anticipation of orbit placement, which started in September 2007 and led to a commencement of the baseline mission in December 2007. During the coast phase the probes were put into a string-of-pearls configuration at 100 s of km to 2 R-E along-track separations, which provided a unique view of the magnetosphere and enabled an unprecedented dataset in anticipation of the first tail season. In this paper we describe the first THEMIS substorm observations, captured during instrument commissioning on March 23, 2007. THEMIS measured the rapid expansion of the plasma sheet at a speed that is commensurate with the simultaneous expansion of the auroras on the ground. These are the first unequivocal observations of the rapid westward expansion process in space and on the ground. Aided by the remote sensing technique at energetic particle boundaries and combined with ancillary measurements and MHD simulations, they allow determination and mapping of space currents. These measurements show the power of the THEMIS instrumentation in the tail and the radiation belts. We also present THEMIS Flux Transfer Events (FTE) observations at the magnetopause, which demonstrate the importance of multi-point observations there and the quality of the THEMIS instrumentation in that region of space.
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| 14. |
- Arab, Khelifa, et al.
(författare)
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Long Noncoding RNA TARID Directs Demethylation and Activation of the Tumor Suppressor TCF21 via GADD45A
- 2014
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Ingår i: Molecular Cell. - : Elsevier BV. - 1097-2765 .- 1097-4164. ; 55:4, s. 604-614
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Tidskriftsartikel (refereegranskat)abstract
- DNA methylation is a dynamic and reversible process that governs gene expression during development and disease. Several examples of active DNA demethylation have been documented, involving genome-wide and gene-specific DNA demethylation. How demethylating enzymes are targeted to specific genomic loci remains largely unknown. We show that an antisense lncRNA, termed TARID (for TCF21 antisense RNA inducing demethylation), activates TCF21 expression by inducing promoter demethylation. TARID interacts with both the TCF21 promoter and GADD45A (growth arrest and DNA-damage-inducible, alpha), a regulator of DNA demethylation. GADD45A in turn recruits thymine-DNA glycosylase for base excision repair-mediated demethylation involving oxidation of 5-methylcytosine to 5-hydroxymethylcytosine in the TCF21 promoter by ten-eleven translocation methylcytosine dioxygenase proteins. The results reveal a function of lncRNAs, serving as a genomic address label for GADD45A-mediated demethylation of specific target genes.
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| 18. |
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| 19. |
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| 20. |
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| 21. |
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| 22. |
- Mende, Max, et al.
(författare)
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Strong Rashba Effect and Different f−d Hybridization Phenomena at the Surface of the Heavy-Fermion Superconductor CeIrIn5
- 2022
-
Ingår i: Advanced Electronic Materials. - : Wiley. - 2199-160X. ; 8:3
-
Tidskriftsartikel (refereegranskat)abstract
- New temperature scales and remarkable differences from bulk properties have increasingly placed the surfaces of strongly correlated f materials into the focus of research activities. Applying first-principles calculations and angle-resolved photoelectron spectroscopy measurements, a strong Rashba effect and spin-split surface states at the CeIn surface of the heavy-fermion superconductor CeIrIn5 are revealed. The unveiled 4f-derived electron landscape is remarkably distinct for surface and bulk Ce implying the existence of novel temperature scales near the surface region in this material. These results show that ab initio calculations can reliably predict the unusual electronic and spin structure of surfaces of strongly correlated 4f systems where Rashba spin-orbit-coupling phenomena emerge. It is suggested that the structural blocks of such materials can be combined with magnetically active layers for engineering of novel nanostructural objects with appropriate substrates where the diversity of f-driven properties can be applied for the development of novel functionalities.
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| 23. |
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| 24. |
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| 25. |
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| 26. |
- Nishimura, Y., et al.
(författare)
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Estimation of magnetic field mapping accuracy using the pulsating aurora-chorus connection
- 2011
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Ingår i: Geophysical Research Letters. - 0094-8276 .- 1944-8007. ; 38, s. L14110-
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Tidskriftsartikel (refereegranskat)abstract
- Although magnetic field models are widely used in magnetosphere-ionosphere coupling studies to perform field-line mapping, their accuracy has been difficult to estimate experimentally. Taking advantage of the high correlation between lower-band chorus and pulsating aurora, we located the THEMIS spacecraft footprint within similar to km accuracy and calculated the differences from mappings given in widely-used Tsyganenko models. Using 13 conjunctions of the THEMIS spacecraft and ground-based imagers, we found that the Tsyganenko model footprints were located within 1 degrees-2 degrees magnetic latitude and 0.1-0.2 h magnetic local time of our derived footprint. The deviation between the footprints has a consistent dependence on geomagnetic activity. Our results showed that the real magnetic field tends to be less stretched than that in the Tsyganenko models during quiet times and comparable to or more stretched during disturbed times. This approach can be used to advance modeling of field lines that connect to the near-Earth plasma sheet.
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| 27. |
- Nishimura, Y., et al.
(författare)
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Multievent study of the correlation between pulsating aurora and whistler mode chorus emissions
- 2011
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Ingår i: Journal of Geophysical Research. - 0148-0227 .- 2156-2202. ; 116, s. A11221-
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Tidskriftsartikel (refereegranskat)abstract
- A multievent study was performed using conjugate measurements of the Time History of Events and Macroscale Interactions during Substorms (THEMIS) spacecraft and an all-sky imager during periods of intense lower-band chorus waves. The thirteen identified cases support our previous finding, based on two events, that the intensity modulation of lower-band chorus near the magnetic equator is highly correlated with quasiperiodic pulsating auroral emissions near the spacecraft's magnetic footprint, indicating that lower-band chorus is the driver of the pulsating aurora. Furthermore, we identified a fortuitous measurement made simultaneously by two THEMIS spacecraft with small spatial separation. The two spacecraft were found to be located in a single pulsating chorus patch and the spacecraft footprints were in the same pulsating auroral patch when intense chorus bursts were measured simultaneously, whereas only one of the spacecraft's footprints was in a patch when the other spacecraft did not detect intense chorus. On the basis of this event, we can estimate the pulsating chorus patch size by mapping the pulsating auroral patches from the ionosphere toward the magnetic equator, giving a roughly circular region of similar to 5000 km diameter for corresponding azimuthally elongated patches with similar to 100 km size in the ionosphere. Using a ray-tracing-based calculation of the divergence of chorus raypaths from a point source, together with the corresponding resonant energies, we found that the chorus patch size is most probably not a result of ray divergence but a property of the wave excitation region.
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| 28. |
- Pavlova, A., et al.
(författare)
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Impact of polymorphisms of the major histocompatibility complex class II, interleukin-10, tumor necrosis factor-alpha and cytotoxic T-lymphocyte antigen-4 genes on inhibitor development in severe hemophilia A
- 2009
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Ingår i: Journal of Thrombosis and Haemostasis. - : Elsevier BV. - 1538-7933 .- 1538-7836. ; 7:12, s. 2006-2015
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Tidskriftsartikel (refereegranskat)abstract
- Background: Approximately 25% of severe hemophilia A (HA) patients develop antibodies to factor VIII protein. Patients: In the present case-controlled cohort study, 260 severely affected, mutation-type-matched HA patients were studied for association of human leukocyte antigen (HLA) class II molecules and polymorphisms in the genes encoding interleukin-10 (IL-10), tumor necrosis factor-alpha (TNF-alpha) and cytotoxic T-lymphocyte antigen-4 (CTLA-4) and development of inhibitors. Results: Our results demonstrate a higher frequency of DRB1*15 and DQB1*0602 alleles as well as of the haplotype DRB1*15/DQB1*0602 in inhibitor patients [odds ratio (OR) 1.9; P < 0.05]. In TNF-alpha, the A allele of the -308G > A polymorphism was found with higher frequency in the inhibitor cohort (0.22 vs. 0.13, OR 1.80). This finding was more pronounced for the homozygous A/A genotype (OR 4.7). For IL-10, the -1082G allele was observed more frequently in patients with inhibitors (0.55 vs. 0.43; P = 0.008). The functional cytokine phenotype was determined for the first time, on the basis of the genetic background, and this showed that 12% of patients with inhibitors were high-TNF-alpha/high-IL-10 producers, as compared with 3% of non-inhibitor patients (OR 4.4). A trend for a lower frequency of the A allele of the CT60 polymorphism in CTLA-4 was found in inhibitor patients (0.42 vs. 0.50). Conclusions: In conclusion, the reported data clearly highlighted the participation of HLA molecules in inhibitor formation in a large cohort of patients. The higher frequencies of the -308G > A polymorphism in TNF-alpha and -1082A > G in IL-10 in inhibitor patients confirmed the earlier published data. The CT60 single-nucleotide polymorphism in CTLA-4 is of apparently less importance.
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