| 1. |
- Aad, G, et al.
(författare)
-
- 2015
-
swepub:Mat__t
|
|
| 2. |
-
Modulated High-Energy Gamma-Ray Emission from the Microquasar Cygnus X-3
- 2009
-
Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 326:5959, s. 1512-
-
Tidskriftsartikel (refereegranskat)abstract
- Microquasars are accreting black holes or neutron stars in binary systems with associated relativistic jets. Despite their frequent outburst activity, they have never been unambiguously detected emitting high-energy gamma rays. The Fermi Large Area Telescope (LAT) has detected a variable high-energy source coinciding with the position of the x-ray binary and microquasar Cygnus X-3. Its identification with Cygnus X-3 is secured by the detection of its orbital period in gamma rays, as well as the correlation of the LAT flux with radio emission from the relativistic jets of Cygnus X-3. The gamma-ray emission probably originates from within the binary system, opening new areas in which to study the formation of relativistic jets.
|
|
| 3. |
- Kim, Jae-Young, et al.
(författare)
-
Event Horizon Telescope imaging of the archetypal blazar 3C 279 at an extreme 20 microarcsecond resolution
- 2020
-
Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 640
-
Tidskriftsartikel (refereegranskat)abstract
- 3C 279 is an archetypal blazar with a prominent radio jet that show broadband flux density variability across the entire electromagnetic spectrum. We use an ultra-high angular resolution technique - global Very Long Baseline Interferometry (VLBI) at 1.3mm (230 GHz) - to resolve the innermost jet of 3C 279 in order to study its fine-scale morphology close to the jet base where highly variable-ray emission is thought to originate, according to various models. The source was observed during four days in April 2017 with the Event Horizon Telescope at 230 GHz, including the phased Atacama Large Millimeter/submillimeter Array, at an angular resolution of ∼20 μas (at a redshift of z = 0:536 this corresponds to ∼0:13 pc ∼ 1700 Schwarzschild radii with a black hole mass MBH = 8 × 108 M⊙). Imaging and model-fitting techniques were applied to the data to parameterize the fine-scale source structure and its variation.We find a multicomponent inner jet morphology with the northernmost component elongated perpendicular to the direction of the jet, as imaged at longer wavelengths. The elongated nuclear structure is consistent on all four observing days and across diffierent imaging methods and model-fitting techniques, and therefore appears robust. Owing to its compactness and brightness, we associate the northern nuclear structure as the VLBI "core". This morphology can be interpreted as either a broad resolved jet base or a spatially bent jet.We also find significant day-to-day variations in the closure phases, which appear most pronounced on the triangles with the longest baselines. Our analysis shows that this variation is related to a systematic change of the source structure. Two inner jet components move non-radially at apparent speeds of ∼15 c and ∼20 c (∼1:3 and ∼1:7 μas day-1, respectively), which more strongly supports the scenario of traveling shocks or instabilities in a bent, possibly rotating jet. The observed apparent speeds are also coincident with the 3C 279 large-scale jet kinematics observed at longer (cm) wavelengths, suggesting no significant jet acceleration between the 1.3mm core and the outer jet. The intrinsic brightness temperature of the jet components are ≤1010 K, a magnitude or more lower than typical values seen at ≥7mm wavelengths. The low brightness temperature and morphological complexity suggest that the core region of 3C 279 becomes optically thin at short (mm) wavelengths.
|
|
| 4. |
|
|
| 5. |
- Allentoft, Morten E., et al.
(författare)
-
Population genomics of post-glacial western Eurasia
- 2024
-
Ingår i: Nature. - 0028-0836 .- 1476-4687. ; 625:7994, s. 301-311
-
Tidskriftsartikel (refereegranskat)abstract
- Western Eurasia witnessed several large-scale human migrations during the Holocene1–5. Here, to investigate the cross-continental effects of these migrations, we shotgun-sequenced 317 genomes—mainly from the Mesolithic and Neolithic periods—from across northern and western Eurasia. These were imputed alongside published data to obtain diploid genotypes from more than 1,600 ancient humans. Our analyses revealed a ‘great divide’ genomic boundary extending from the Black Sea to the Baltic. Mesolithic hunter-gatherers were highly genetically differentiated east and west of this zone, and the effect of the neolithization was equally disparate. Large-scale ancestry shifts occurred in the west as farming was introduced, including near-total replacement of hunter-gatherers in many areas, whereas no substantial ancestry shifts happened east of the zone during the same period. Similarly, relatedness decreased in the west from the Neolithic transition onwards, whereas, east of the Urals, relatedness remained high until around 4,000 bp, consistent with the persistence of localized groups of hunter-gatherers. The boundary dissolved when Yamnaya-related ancestry spread across western Eurasia around 5,000 bp, resulting in a second major turnover that reached most parts of Europe within a 1,000-year span. The genetic origin and fate of the Yamnaya have remained elusive, but we show that hunter-gatherers from the Middle Don region contributed ancestry to them. Yamnaya groups later admixed with individuals associated with the Globular Amphora culture before expanding into Europe. Similar turnovers occurred in western Siberia, where we report new genomic data from a ‘Neolithic steppe’ cline spanning the Siberian forest steppe to Lake Baikal. These prehistoric migrations had profound and lasting effects on the genetic diversity of Eurasian populations.
|
|
| 6. |
- Bolton, Ruth N., et al.
(författare)
-
Customer experience challenges : bringing together digital, physical and social realms
- 2018
-
Ingår i: Journal of Service Management. - : Emerald Group Publishing Limited. - 1757-5818 .- 1757-5826. ; 29:5, s. 776-808
-
Tidskriftsartikel (refereegranskat)abstract
- Purpose The purpose of this paper is to explore innovations in customer experience at the intersection of the digital, physical and social realms. It explicitly considers experiences involving new technology-enabled services, such as digital twins and automated social presence (i.e. virtual assistants and service robots). Design/methodology/approach Future customer experiences are conceptualized within a three-dimensional space - low to high digital density, low to high physical complexity and low to high social presence - yielding eight octants. Findings The conceptual framework identifies eight dualities, or specific challenges connected with integrating digital, physical and social realms that challenge organizations to create superior customer experiences in both business-to-business and business-to-consumer markets. The eight dualities are opposing strategic options that organizations must reconcile when co-creating customer experiences under different conditions. Research limitations/implications A review of theory demonstrates that little research has been conducted at the intersection of the digital, physical and social realms. Most studies focus on one realm, with occasional reference to another. This paper suggests an agenda for future research and gives examples of fruitful ways to study connections among the three realms rather than in a single realm. Practical implications This paper provides guidance for managers in designing and managing customer experiences that the authors believe will need to be addressed by the year 2050. Social implications This paper discusses important societal issues, such as individual and societal needs for privacy, security and transparency. It sets out potential avenues for service innovation in these areas. Originality/value The conceptual framework integrates knowledge about customer experiences in digital, physical and social realms in a new way, with insights for future service research, managers and public policy makers.
|
|
| 7. |
- Bolton, Ruth N., et al.
(författare)
-
Small details that make big differences : A radical approach to consumption experience as a firm's differentiating strategy
- 2014
-
Ingår i: Journal of Service Management. - 1757-5818 .- 1757-5826. ; 25:2, s. 253-274
-
Tidskriftsartikel (refereegranskat)abstract
- Purpose - Service organizations and marketers have focussed too much of their energy on their core service's performance and too little emphasis on designing a customer journey that enhances the entire customer experience. There is nothing wrong with firms seeking continuous improvement in service quality and customer satisfaction. These efforts are needed for firms to be competitive in the marketplace. The problem occurs when performance levels and service offerings become too similar within an industry, so that price is the only competitive weapon that remains. The purpose of this paper is to argue that in order to break this deadlock, companies need to focus on the small details that make big differences to customers. Design/methodology/approach - The paper builds on interviews with executives in successful service organizations. It provides an analysis of differentiation strategies in diverse service organizations across consumption contexts, nations and cultures around the world. Findings - The paper develops three research propositions and argues for radical approaches to help service organizations truly understand customers and provide service experiences that engage and delight them. The paper argues that the new challenge for marketing is to help companies find and implement these small details to make a large impact on the overall customer experience. Originality/value - In order to truly understand the customer experience, the paper need a holistic view of all interactions customers have with a company. The paper need to understand the customer-firm interactions at all touch points, that is, during search, purchase, consumption and post-consumption. Customer experience involves the customers' cognitive, affective, emotional, social and sensory responses to the firm. The originality of this research lies in the focus on the small details that make a difference to customers during the service process rather than in the final outcome of the service performance.
|
|
| 8. |
- Irving-Pease, Evan K., et al.
(författare)
-
The selection landscape and genetic legacy of ancient Eurasians
- 2024
-
Ingår i: Nature. - 0028-0836 .- 1476-4687. ; 625, s. 312-320
-
Tidskriftsartikel (refereegranskat)abstract
- The Holocene (beginning around 12,000 years ago) encompassed some of the most significant changes in human evolution, with far-reaching consequences for the dietary, physical and mental health of present-day populations. Using a dataset of more than 1,600 imputed ancient genomes 1, we modelled the selection landscape during the transition from hunting and gathering, to farming and pastoralism across West Eurasia. We identify key selection signals related to metabolism, including that selection at the FADS cluster began earlier than previously reported and that selection near the LCT locus predates the emergence of the lactase persistence allele by thousands of years. We also find strong selection in the HLA region, possibly due to increased exposure to pathogens during the Bronze Age. Using ancient individuals to infer local ancestry tracts in over 400,000 samples from the UK Biobank, we identify widespread differences in the distribution of Mesolithic, Neolithic and Bronze Age ancestries across Eurasia. By calculating ancestry-specific polygenic risk scores, we show that height differences between Northern and Southern Europe are associated with differential Steppe ancestry, rather than selection, and that risk alleles for mood-related phenotypes are enriched for Neolithic farmer ancestry, whereas risk alleles for diabetes and Alzheimer’s disease are enriched for Western hunter-gatherer ancestry. Our results indicate that ancient selection and migration were large contributors to the distribution of phenotypic diversity in present-day Europeans.
|
|
| 9. |
|
|
| 10. |
- Seersholm, Frederik Valeur, et al.
(författare)
-
Repeated plague infections across six generations of Neolithic Farmers
- 2024
-
Ingår i: Nature. - 0028-0836 .- 1476-4687.
-
Tidskriftsartikel (refereegranskat)abstract
- In the period between 5,300 and 4,900 calibratedyears before present (cal. bp), populations across large parts of Europe underwent a period of demographic decline1,2. However, the cause of this so-called Neolithic decline is still debated. Some argue for an agricultural crisis resulting in the decline3, others for the spread of an early form of plague4. Here we use population-scale ancient genomics to infer ancestry, social structure and pathogen infection in 108 Scandinavian Neolithic individuals from eight megalithic graves and a stone cist. We find that the Neolithic plague was widespread, detected in at least 17% of the sampled population and across large geographical distances. We demonstrate that the disease spread within the Neolithic community in three distinct infection events within a period of around 120 years. Variant graph-based pan-genomics shows that the Neolithic plague genomes retained ancestral genomic variation present in Yersinia pseudotuberculosis, including virulence factors associated with disease outcomes. In addition, we reconstruct four multigeneration pedigrees, the largest of which consists of 38 individuals spanning six generations, showing a patrilineal social organization. Lastly, we document direct genomic evidence for Neolithic female exogamy in a woman buried in a different megalithic tomb than her brothers. Taken together, our findings provide a detailed reconstruction of plague spread within a large patrilineal kinship group and identify multiple plague infections in a population dated to the beginning of the Neolithic decline.
|
|
| 11. |
- Sikora, M., et al.
(författare)
-
The population history of northeastern Siberia since the Pleistocene
- 2019
-
Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 570:7760
-
Tidskriftsartikel (refereegranskat)abstract
- Northeastern Siberia has been inhabited by humans for more than 40,000 years but its deep population history remains poorly understood. Here we investigate the late Pleistocene population history of northeastern Siberia through analyses of 34 newly recovered ancient genomes that date to between 31,000 and 600 years ago. We document complex population dynamics during this period, including at least three major migration events: an initial peopling by a previously unknown Palaeolithic population of 'Ancient North Siberians' who are distantly related to early West Eurasian hunter-gatherers; the arrival of East Asian-related peoples, which gave rise to 'Ancient Palaeo-Siberians' who are closely related to contemporary communities from far-northeastern Siberia (such as the Koryaks), as well as Native Americans; and a Holocene migration of other East Asian-related peoples, who we name 'Neo-Siberians', and from whom many contemporary Siberians are descended. Each of these population expansions largely replaced the earlier inhabitants, and ultimately generated the mosaic genetic make-up of contemporary peoples who inhabit a vast area across northern Eurasia and the Americas.
|
|
| 12. |
|
|
| 13. |
- van der Meer, PF, et al.
(författare)
-
Aggregates in platelet concentrates
- 2015
-
Ingår i: Vox sanguinis. - : Wiley. - 1423-0410 .- 0042-9007. ; 108:1, s. 96-125
-
Tidskriftsartikel (refereegranskat)
|
|
