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| 2. |
- Aartsen, M. G., et al.
(författare)
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Development of an analysis to probe the neutrino mass ordering with atmospheric neutrinos using three years of IceCube DeepCore data IceCube Collaboration
- 2020
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Ingår i: European Physical Journal C. - : SPRINGER. - 1434-6044 .- 1434-6052. ; 80:1
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Tidskriftsartikel (refereegranskat)abstract
- The Neutrino Mass Ordering (NMO) remains one of the outstanding questions in the field of neutrino physics. One strategy to measure the NMO is to observe matter effects in the oscillation pattern of atmospheric neutrinos above similar to 1GeV, as proposed for several next-generation neutrino experiments. Moreover, the existing IceCube DeepCore detector can already explore this type of measurement. We present the development and application of two independent analyses to search for the signature of the NMO with three years of DeepCore data. These analyses include a full treatment of systematic uncertainties and a statistically-rigorous method to determine the significance for the NMO from a fit to the data. Both analyses show that the dataset is fully compatible with both mass orderings. For the more sensitive analysis, we observe a preference for normal ordering with a p-value of pIO=15.3% and CLs=53.3% for the inverted ordering hypothesis, while the experimental results from both analyses are consistent within their uncertainties. Since the result is independent of the value of delta CP and obtained from energies E nu greater than or similar to 5GeV, it is complementary to recent results from long-baseline experiments. These analyses set the groundwork for the future of this measurement with more capable detectors, such as the IceCube Upgrade and the proposed PINGU detector.
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| 3. |
- Aartsen, M. G., et al.
(författare)
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Neutrinos below 100 TeV from the southern sky employing refined veto techniques to IceCube data
- 2020
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Ingår i: Astroparticle physics. - : ELSEVIER. - 0927-6505 .- 1873-2852. ; 116
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Tidskriftsartikel (refereegranskat)abstract
- Many Galactic sources of gamma rays, such as supernova remnants, are expected to produce neutrinos with a typical energy cutoff well below 100 TeV. For the IceCube Neutrino Observatory located at the South Pole, the southern sky, containing the inner part of the Galactic plane and the Galactic Center, is a particularly challenging region at these energies, because of the large background of atmospheric muons. In this paper, we present recent advancements in data selection strategies for track-like muon neutrino events with energies below 100 TeV from the southern sky. The strategies utilize the outer detector regions as veto and features of the signal pattern to reduce the background of atmospheric muons to a level which, for the first time, allows IceCube searching for point-like sources of neutrinos in the southern sky at energies between 100 GeV and several TeV in the muon neutrino charged current channel. No significant clustering of neutrinos above background expectation was observed in four years of data recorded with the completed IceCube detector. Upper limits on the neutrino flux for a number of spectral hypotheses are reported for a list of astrophysical objects in the southern hemisphere.
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| 6. |
- Stahl, K., et al.
(författare)
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Search for proton emission of the isomeric 10+ state in 54Ni
- 2020
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Ingår i: European Physical Journal A. - : Springer Science and Business Media LLC. - 1434-6001 .- 1434-601X. ; 56:1
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Tidskriftsartikel (refereegranskat)abstract
- Several experiments were conducted at the 10 MV Van-de-Graaff tandem accelerator at the Institute of Nuclear Physics, Cologne, to detect proton emission from the isomeric 6457-keV 10+ state in 54Ni. Excitation functions for two fusion–evaporation reactions were measured to maximise the population of the rare two-neutron evaporation channel from a 56Ni compound nucleus. The search for delayed proton emission was based on the 28Si(28Si,2n)54Ni reaction at a beam energy of 70 MeV. For this reaction, a cross-section limit for the population of the 10+ state in 54Ni and its proton-decay branch was determined to be σ< 22 nb.
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| 7. |
- Brodin, O, et al.
(författare)
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Selenoprotein P as Biomarker of Selenium Status in Clinical Trials with Therapeutic Dosages of Selenite
- 2020
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Ingår i: Nutrients. - : MDPI AG. - 2072-6643. ; 12:4
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Tidskriftsartikel (refereegranskat)abstract
- Selenoprotein P (SELENOP) is an established biomarker of selenium (Se) status. Serum SELENOP becomes saturated with increasing Se intake, reaching maximal concentrations of 5–7 mg SELENOP/L at intakes of ca. 100–150 µg Se/d. A biomarker for higher Se intake is missing. We hypothesized that SELENOP may also reflect Se status in clinical applications of therapeutic dosages of selenite. To this end, blood samples from two supplementation studies employing intravenous application of selenite at dosages >1 mg/d were analyzed. Total Se was quantified by spectroscopy, and SELENOP by a validated ELISA. The high dosage selenite infusions increased SELENOP in parallel to elevated Se concentrations relatively fast to final values partly exceeding 10 mg SELENOP/L. Age or sex were not related to the SELENOP increase. Western blot analyses of SELENOP verified the results obtained by ELISA, and indicated an unchanged pattern of immunoreactive protein isoforms. We conclude that the saturation of SELENOP concentrations observed in prior studies with moderate Se dosages (<400 µg/d) may reflect an intermediate plateau of expression, rather than an absolute upper limit. Circulating SELENOP seems to be a suitable biomarker for therapeutic applications of selenite exceeding the recommended upper intake levels. Whether SELENOP is also capable of reflecting other supplemental selenocompounds in high dosage therapeutic applications remains to be investigated.
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| 8. |
- Heuer, V. B., et al.
(författare)
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Temperature limits to deep subseafloor life in the Nankai Trough subduction zone
- 2020
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 370:6521, s. 1230-1234
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Tidskriftsartikel (refereegranskat)abstract
- Microorganisms in marine subsurface sediments substantially contribute to global biomass. Sediments warmer than 40 degrees C account for roughly half the marine sediment volume, but the processes mediated by microbial populations in these hard-to-access environments are poorly understood. We investigated microbial life in up to 1.2-kilometer-deep and up to 120 degrees C hot sediments in the Nankai Trough subduction zone. Above 45 degrees C, concentrations of vegetative cells drop two orders of magnitude and endospores become more than 6000 times more abundant than vegetative cells. Methane is biologically produced and oxidized until sediments reach 80 degrees to 85 degrees C. In 100 degrees to 120 degrees C sediments, isotopic evidence and increased cell concentrations demonstrate the activity of acetate-degrading hyperthermophiles. Above 45 degrees C, populated zones alternate with zones up to 192 meters thick where microbes were undetectable.
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| 9. |
- Sæþórsdóttir, Anna Dóra, et al.
(författare)
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From boiling to frozen? The rise and fall of international tourism to iceland in the era of overtourism
- 2020
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Ingår i: Environments - MDPI. - : MDPI AG. - 2076-3298. ; 7:8, s. 1-19
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Tidskriftsartikel (refereegranskat)abstract
- Overtourism has emerged as a common concept to describe the perceived negative impacts that large numbers of tourists can have on destinations. Iceland is one of the destinations which has been most associated with the concept of overtourism. Tourism in Iceland grew rapidly from 2010 to 2019, much higher than in most other countries, with Iceland reaching a ranking as high as thirteenth on a list of countries with the highest ratio of tourists per inhabitant. The increase in visitors to the country has had various impacts on Iceland’s economy, society and environment. This paper provides an overview of the different ways in which overtourism has revealed itself at a national level in Iceland. The implications of supposed overtourism are shown to be complex, with management responses limited by their relative focus.
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| 10. |
- Sæthórsdóttir, Anna Dóra, et al.
(författare)
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Overtourism in Iceland : Fantasy or reality?
- 2020
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Ingår i: Sustainability (Switzerland). - 2071-1050. ; 12:18
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Tidskriftsartikel (refereegranskat)abstract
- Iceland has been one of the main destinations that have been incorporated into the discourse of overtourism. However, Iceland is different to many other supposed overtourism destinations in that its tourism is based on natural areas. Nevertheless, destination discourses can play an important part in influencing tourist decision-making and government and industry policy making. A media analysis was conducted of 507 online media articles on overtourism in Iceland that were published in 2018, with the main themes being identified via content analysis. The results indicated that the media discourse represented only a partial picture of overtourism and the crowding phenomenon in Iceland, with mechanisms to respond to crowding, the satisfaction level of tourists with their Icelandic nature experience, and local people's support for tourism being underreported. Some of the findings reflect that of other media analyses. However, there are considerable discontinuities between media representations and discourses of overtourism in Iceland, which highlight the importance of national-or destination-level media analysis. The media analysis illustrates the need for a better understanding of different destination discourses and their influence.
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