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| 2. |
- Glasbey, JC, et al.
(författare)
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- 2021
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swepub:Mat__t
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| 3. |
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| 4. |
- Bravo, L, et al.
(författare)
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- 2021
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swepub:Mat__t
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| 5. |
- Tabiri, S, et al.
(författare)
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- 2021
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swepub:Mat__t
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| 9. |
- Abdollahi, S., et al.
(författare)
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Fermi Large Area Telescope Fourth Source Catalog
- 2020
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Ingår i: Astrophysical Journal Supplement Series. - : American Astronomical Society. - 0067-0049 .- 1538-4365. ; 247:1
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Tidskriftsartikel (refereegranskat)abstract
- We present the fourth Fermi Large Area Telescope catalog (4FGL) of gamma-ray sources. Based on the first eight years of science data from the Fermi Gamma-ray Space Telescope mission in the energy range from 50 MeV to 1 TeV, it is the deepest yet in this energy range. Relative to the 3FGL catalog, the 4FGL catalog has twice as much exposure as well as a number of analysis improvements, including an updated model for the Galactic diffuse gamma-ray emission, and two sets of light curves (one-year and two-month intervals). The 4FGL catalog includes 5064 sources above 4 sigma significance, for which we provide localization and spectral properties. Seventy-five sources are modeled explicitly as spatially extended, and overall, 358 sources are considered as identified based on angular extent, periodicity, or correlated variability observed at other wavelengths. For 1336 sources, we have not found plausible counterparts at other wavelengths. More than 3130 of the identified or associated sources are active galaxies of the blazar class, and 239 are pulsars.
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| 10. |
- Abdollahi, S., et al.
(författare)
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Incremental Fermi Large Area Telescope Fourth Source Catalog
- 2022
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Ingår i: Astrophysical Journal Supplement Series. - : American Astronomical Society. - 0067-0049 .- 1538-4365. ; 260:2
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Tidskriftsartikel (refereegranskat)abstract
- We present an incremental version (4FGL-DR3, for Data Release 3) of the fourth Fermi Large Area Telescope (LAT) catalog of γ-ray sources. Based on the first 12 years of science data in the energy range from 50 MeV to 1 TeV, it contains 6658 sources. The analysis improves on that used for the 4FGL catalog over eight years of data: more sources are fit with curved spectra, we introduce a more robust spectral parameterization for pulsars, and we extend the spectral points to 1 TeV. The spectral parameters, spectral energy distributions, and associations are updated for all sources. Light curves are rebuilt for all sources with 1 yr intervals (not 2 month intervals). Among the 5064 original 4FGL sources, 16 were deleted, 112 are formally below the detection threshold over 12 yr (but are kept in the list), while 74 are newly associated, 10 have an improved association, and seven associations were withdrawn. Pulsars are split explicitly between young and millisecond pulsars. Pulsars and binaries newly detected in LAT sources, as well as more than 100 newly classified blazars, are reported. We add three extended sources and 1607 new point sources, mostly just above the detection threshold, among which eight are considered identified, and 699 have a plausible counterpart at other wavelengths. We discuss the degree-scale residuals to the global sky model and clusters of soft unassociated point sources close to the Galactic plane, which are possibly related to limitations of the interstellar emission model and missing extended sources.
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| 11. |
- Abdalla, H., et al.
(författare)
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LMC N132D : A mature supernova remnant with a power-law gamma-ray spectrum extending beyond 8 TeV
- 2021
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 655
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Tidskriftsartikel (refereegranskat)abstract
- Context. Supernova remnants (SNRs) are commonly thought to be the dominant sources of Galactic cosmic rays up to the knee of the cosmic-ray spectrum at a few PeV. Imaging Atmospheric Cherenkov Telescopes have revealed young SNRs as very-high-energy (VHE, >100 GeV) gamma-ray sources, but for only a few SNRs the hadronic cosmic-ray origin of their gamma-ray emission is indisputably established. In all these cases, the gamma-ray spectra exhibit a spectral cutoff at energies much below 100 TeV and thus do not reach the PeVatron regime. Aims. The aim of this work was to achieve a firm detection for the oxygen-rich SNR LMC N132D in the VHE gamma-ray domain with an extended set of data, and to clarify the spectral characteristics and the localization of the gamma-ray emission from this exceptionally powerful gamma-ray-emitting SNR. Methods. We analyzed 252 h of High Energy Stereoscopic System (H.E.S.S.) observations towards SNR N132D that were accumulated between December 2004 and March 2016 during a deep survey of the Large Magellanic Cloud, adding 104 h of observations to the previously published data set to ensure a > 5 sigma detection. To broaden the gamma-ray spectral coverage required for modeling the spectral energy distribution, an analysis of Fermi-LAT Pass 8 data was also included. Results. We unambiguously detect N132D at VHE with a significance of 5.7 sigma. We report the results of a detailed analysis of its spectrum and localization based on the extended H.E.S.S. data set. The joint analysis of the extended H.E.S.S and Fermi-LAT data results in a spectral energy distribution in the energy range from 1.7 GeV to 14.8 TeV, which suggests a high luminosity of N132D at GeV and TeV energies. We set a lower limit on a gamma-ray cutoff energy of 8 TeV with a confidence level of 95%. The new gamma-ray spectrum as well as multiwavelength observations of N132D when compared to physical models suggests a hadronic origin of the VHE gamma-ray emission. Conclusions. SNR N132D is a VHE gamma-ray source that shows a spectrum extending to the VHE domain without a spectral cutoff at a few TeV, unlike the younger oxygen-rich SNR Cassiopeia A. The gamma-ray emission is best explained by a dominant hadronic component formed by diffusive shock acceleration. The gamma-ray properties of N132D may be affected by an interaction with a nearby molecular cloud that partially lies inside the 95% confidence region of the source position.
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| 15. |
- Berghammer, Malin, et al.
(författare)
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The impact of anxiety in relation to COVID-19 on the life-situation of young people in Sweden
- 2021
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Ingår i: Quality of Life Research. - : SPRINGER. - 0962-9343 .- 1573-2649. ; 30:SUPPL 1, s. S4-S4
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Aims: In general, COVID-19 symptoms are milder in children than inadults, but the experience of the pandemic could increase anxiety andsignificantly affect the life situation of children and adolescents. Itcould also lead to a long-term negative effect on their health. To studyhow the corona pandemic affected the life situation of children andadolescents in Sweden. Methods: A self-reported online survey wasperformed July–November 2020. Cross-sectional data were collectedusing non-probability and convenience sampling methods. The sample consisted of children 6–14 years and their guardians, and adolescents 15–19 years. The questionnaire covered items regarding the life situation including demographics, school situation, social isolation, and an open-ended question to provide a subjective expression of the living situation. A standardized measurement of anxiety was collected using the Children’s Anxiety Questionnaire (CAQ) (scores range 4–12) and the Numeric Rating Scale (NRS)(scores range 0–10). Data were analyzed by descriptive statistics andwith qualitative manifest content analysis. Results: In total, 1487 participants, 768 children with guardians and 719 adolescents participated. Most of the participants, 754 children (97.2%) and 634 adolescents (89.2%) attended school where a mixture of physical attendance and distance learning was reported by 79 children (10.2%)and 261 adolescents (36.7%). Two children (0.3%) and 298 adolescents (41.9%) reported only having distance learning. A larger proportion of children (n = 339, 43.9%) and adolescents (n = 420,59.2%) reported abstaining from leisure activities, while a minority ofchildren (n = 103, 13%) and adolescent (n = 135, 19%) reportedexperiencing a feeling of ‘social isolation’. These experiences ofchanges in daily routine were prominent in the qualitative result. Social restrictions and loss of contact with older relatives led to fear and anxiety. However, for young children, their lives continued torevolve around the everyday things in life rather than the coronapandemic, for the adolescents; however, their life situation was negatively affected by isolation from peer groups and the loss ofschool routine. Conclusion: The experiences by children due toCOVID-19 in Sweden highlight the importance that children continue living their lives as unchanged as possible and that particularly adolescents need receiving greater support with the maintenance of an educational routine.
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| 16. |
- Korell, D., et al.
(författare)
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Student-led replication studies in comparative politics: new findings by fresh eyes?
- 2023
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Ingår i: Zeitschrift Fur Vergleichende Politikwissenschaft. - 1865-2646. ; 17:3, s. 261-273
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Tidskriftsartikel (refereegranskat)abstract
- This research note presents two replication studies that were conducted during a research-oriented course at Heidelberg University in summer 2022. The first study, initially conducted by Korell, replicates the findings from Albert's original contribution on rebel governance. Albert conducted an explorative study in analyzing the associations between rebel governance and rebel military capacity. Our replication study indicates support for Albert's argument of the relevance of disaggregating rebel governance, while we also show that the original findings are mainly driven by Albert's explorative model specifications. The second study, initially conducted by Reinecke, tests the robustness of Levin et al.'s study on the democratic peacekeeping hypothesis and expands upon the original study by directly testing the "selectorate-theoretic causal mechanism" for the democratic peacekeeping hypothesis. Overall, the replication studies presented in this research note provide interesting findings regarding empirical conflict studies and contribute to ongoing efforts to promote replication initiatives in the education of future political scientists.
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| 17. |
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| 18. |
- Rydstrom, Lise-Lott, et al.
(författare)
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How children in Sweden accessed and perceived information during the first phase of the Covid-19 pandemic
- 2022
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Ingår i: Scandinavian Journal of Public Health. - : SAGE Publications. - 1403-4948 .- 1651-1905. ; 50:1, s. 144-151
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Tidskriftsartikel (refereegranskat)abstract
- Aim: To describe how children in Sweden accessed and perceived information about SARS-CoV2 and Covid-19 during the first phase of the outbreak. Methods: This study is a substudy of an international cross-sectional online mixed methods survey examining elements of children's health literacy in relation to Covid-19. The survey included multiple-choice questions, open-ended questions and drawings and collected information from 50 Swedish children (7-12 years). Data were analysed concurrently on a descriptive level using statistics and content analysis. Quantitative and qualitative data, including the drawings, were considered equally important and resulted in six categories, illuminating how children accessed and perceived information about the pandemic. Results: The survey showed that children accessed information mainly from school but also from TV. They preferred information from reliable sources. Children reported the information they accessed as easy to understand and it prompted them to ask new questions. They reported they knew a lot about the pandemic, for example, the potential danger to themselves and others and how to act to protect themselves and others. They perceived the pandemic as an intrusion on their lives. Conclusions: This study indicates that Swedish children between 7 and 12 years old were well informed about SARS-CoV2 and Covid-19 during the first phase of the pandemic. School was shown to be an important source of information. The children could explain how to act to protect themselves and others from becoming infected by the virus.
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