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- Ryde, Felix, et al.
(författare)
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IDENTIFICATION AND PROPERTIES OF THE PHOTOSPHERIC EMISSION IN GRB090902B
- 2010
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Ingår i: The Astrophysical Journal Letters. - 2041-8205 .- 2041-8213. ; 709:2, s. l172-L177
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Tidskriftsartikel (refereegranskat)abstract
- The Fermi Gamma-ray Space Telescope observed the bright and long GRB090902B, lying at a redshift of z = 1.822. Together the Large Area Telescope (LAT) and the Gamma-ray Burst Monitor (GBM) cover the spectral range from 8 keV to >300 GeV. Here we show that the prompt burst spectrum is consistent with emission from the jet photosphere combined with nonthermal emission described by a single power law with photon index -1.9. The photosphere gives rise to a strong quasi-blackbody spectrum which is somewhat broader than a single Planck function and has a characteristic temperature of similar to 290 keV. We model the photospheric emission with a multicolor blackbody, and its shape indicates that the photospheric radius increases at higher latitudes. We derive the averaged photospheric radius R-ph = (1.1 +/- 0.3) x 10(12) Y-1/4 cm and the bulk Lorentz factor of the flow, which is found to vary by a factor of 2 and has a maximal value of Gamma = 750 Y-1/4. Here, Y is the ratio between the total fireball energy and the energy emitted in the gamma rays. We find that during the first quarter of the prompt phase the photospheric emission dominates, which explains the delayed onset of the observed flux in the LAT compared to the GBM. We interpret the broadband emission as synchrotron emission at R similar to 4 x 10(15) cm. Our analysis emphasizes the importance of having high temporal resolution when performing spectral analysis on gamma-ray bursts, since there is strong spectral evolution.
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| 2. |
- Axelsson, Magnus, et al.
(författare)
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GRB110721A : AN EXTREME PEAK ENERGY AND SIGNATURES OF THE PHOTOSPHERE
- 2012
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Ingår i: Astrophysical Journal Letters. - 2041-8205. ; 757:2
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Tidskriftsartikel (refereegranskat)abstract
- GRB110721A was observed by the Fermi Gamma-ray Space Telescope using its two instruments, the Large Area Telescope (LAT) and the Gamma-ray Burst Monitor (GBM). The burst consisted of one major emission episode which lasted for similar to 24.5 s (in the GBM) and had a peak flux of (5.7 +/- 0.2) x 10(-5) erg s(-1) cm(-2). The time-resolved emission spectrum is best modeled with a combination of a Band function and a blackbody spectrum. The peak energy of the Band component was initially 15 +/- 2 MeV, which is the highest value ever detected in a GRB. This measurement was made possible by combining GBM/BGO data with LAT Low Energy events to achieve continuous 10-100 MeV coverage. The peak energy later decreased as a power law in time with an index of -1.89 +/- 0.10. The temperature of the blackbody component also decreased, starting from similar to 80 keV, and the decay showed a significant break after similar to 2 s. The spectrum provides strong constraints on the standard synchrotron model, indicating that alternative mechanisms may give rise to the emission at these energies.
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| 6. |
- Edfors, R., et al.
(författare)
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Use of proteomics to identify biomarkers associated with chronic kidney disease and long-term outcomes in patients with myocardial infarction
- 2020
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Ingår i: Journal of Internal Medicine. - : Wiley. - 0954-6820 .- 1365-2796. ; 288:5, s. 581-592
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Tidskriftsartikel (refereegranskat)abstract
- Background Patients with chronic kidney disease (CKD) have poor outcomes following myocardial infarction (MI). We performed an untargeted examination of 175 biomarkers to identify those with the strongest association with CKD and to examine the association of those biomarkers with long-term outcomes. Methods A total of 175 different biomarkers from MI patients enrolled in the Swedish Web-System for Enhancement and Development of Evidence-Based Care in Heart Disease Evaluated According to Recommended Therapies (SWEDEHEART) registry were analysed either by a multiple reaction monitoring mass spectrometry assay or by a multiplex assay (proximity extension assay). Random forests statistical models were used to assess the predictor importance of biomarkers, CKD and outcomes. Results A total of 1098 MI patients with a median estimated glomerular filtration rate of 85 mL min(-1)/1.73 m(2)were followed for a median of 3.2 years. The random forests analyses, without and with adjustment for differences in demography, comorbidities and severity of disease, identified six biomarkers (adrenomedullin, TNF receptor-1, adipocyte fatty acid-binding protein-4, TNF-related apoptosis-inducing ligand receptor 2, growth differentiation factor-15 and TNF receptor-2) to be strongly associated with CKD. All six biomarkers were also amongst the 15 strongest predictors for death, and four of them were amongst the strongest predictors of subsequent MI and heart failure hospitalization. Conclusion In patients with MI, a proteomic approach could identify six biomarkers that best predicted CKD. These biomarkers were also amongst the most important predictors of long-term outcomes. Thus, these biomarkers indicate underlying mechanisms that may contribute to the poor prognosis seen in patients with MI and CKD.
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| 8. |
- Ekman, Inger, 1952, et al.
(författare)
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Health-related quality of life and sense of coherence among elderly patients with severe chronic heart failure in comparison with healthy controls
- 2002
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Ingår i: Heart & Lung. - 0147-9563. ; 31:2, s. 94-101
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To describe health-related quality of life (QoL) and sense of coherence (SOC) in a group of elderly people with moderate to severe chronic heart failure and to make comparisons with a healthy sex- and age-matched control group. METHODS: Patients (n = 94), with a mean age of 81 years, hospitalized for chronic heart failure with New York Heart Association functional classification III to IV were age- and sex-matched to a healthy control group. The instruments used were the 36-Item Short Form Health Survey (SF-36) and SOC. RESULTS: The patients had lower levels of health-related QoL scores (SF-36) but high and similar scores of SOC compared with the controls. There were, however, significant positive correlations between the SOC scores and the emotional dimensions in the SF-36 instrument. CONCLUSION: The findings from this study indicate that old age and severe chronic heart failure were associated with limited functional abilities and impaired health-related QoL but also with internal resources such as SOC.
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| 10. |
- Ekman, Inger, 1952, et al.
(författare)
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The meaning of hospital care as narrated by elderly patients with chronic heart failure
- 1999
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Ingår i: Heart & Lung. - 0147-9563. ; 28:3, s. 203-9
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Tidskriftsartikel (refereegranskat)abstract
- Chronic heart failure is the most common reason for hospitalization among the elderly in western societies. To elucidate the meaning of the experience of care received in the hospital, as narrated by 12 elderly patients with severe chronic heart failure, interviews were analyzed by an approach inspired by Ricoeur's phenomenologic hermeneutics. The analysis revealed that the study respondents experienced the care as "unpredictable." This essential theme captured the divergent descriptions of 2 subthemes: care was either "confident but incomprehensible" or "nonconfident and incomprehensible." When the patients sought care, it was as though they were launching themselves into the unknown because they knew that many experiences would be unpredictable. Despite experiences of indifferent and unpredictable care, the narratives revealed a need to rely on the caregivers' expertise.
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