| 1. |
- Raiteri, C. M., et al.
(författare)
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WEBT and XMM-Newton observations of 3C 454.3 during the post-outburst phase - Detection of the little and big blue bumps
- 2007
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 473:3, s. 819-827
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Tidskriftsartikel (refereegranskat)abstract
- Context. The quasar-type blazar 3C 454.3 was observed to undergo an unprecedented optical outburst in spring 2005, affecting the source brightness from the near-IR to the X-ray frequencies. This was first followed by a millimetric and then by a radio outburst, which peaked in February 2006. Aims. In this paper we report on follow-up observations to study the multiwavelength emission in the post-outburst phase. Methods. Radio, near-infrared, and optical monitoring was performed by the Whole Earth Blazar Telescope (WEBT) collaboration in the 2006-2007 observing season. XMM-Newton observations on July 2-3 and December 18-19, 2006 added information on the X-ray and UV states of the source. Results. The source was in a faint state. The radio flux at the higher frequencies showed a fast decreasing trend, which represents the tail of the big radio outburst. It was followed by a quiescent state, common at all radio frequencies. In contrast, moderate activity characterized the near-IR and optical light curves, with a progressive increase of the variability amplitude with increasing wavelength. We ascribe this redder-when-brighter behaviour to the presence of a ""little blue bump"" due to line emission from the broad line region, which is clearly visible in the source spectral energy distribution (SED) during faint states. Moreover, the data from the XMM- Newton Optical Monitor reveal a rise of the SED in the ultraviolet, suggesting the existence of a "" big blue bump"" due to thermal emission from the accretion disc. The X-ray spectra are well fitted with a power- law model with photoelectric absorption, possibly larger than the Galactic one. However, the comparison with previous X-ray observations would imply that the amount of absorbing matter is variable. Alternatively, the intrinsic X-ray spectrum presents a curvature, which may depend on the X-ray brightness. In this case, two scenarios are possible. i) There is no extra absorption, and the X-ray spectrum hardens at low energies, the hardening being more evident in bright states; ii) there is a constant amount of extra absorption, likely in the quasar environment, and the X-ray spectrum softens at low energies, at least in faint X-ray states. This softening might be the result of a flux contribution by the high-frequency tail of the big blue bump.
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| 2. |
- Shin, J. H., et al.
(författare)
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IA-2 autoantibodies in incident type I diabetes patients are associated with a polyadenylation signal polymorphism in GIMAP5
- 2007
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Ingår i: Genes Immun. - : Springer Science and Business Media LLC. - 1466-4879 .- 1476-5470. ; 8:6, s. 503-12
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Tidskriftsartikel (refereegranskat)abstract
- In a large case-control study of Swedish incident type I diabetes patients and controls, 0-34 years of age, we tested the hypothesis that the GIMAP5 gene, a key genetic factor for lymphopenia in spontaneous BioBreeding rat diabetes, is associated with type I diabetes; with islet autoantibodies in incident type I diabetes patients or with age at clinical onset in incident type I diabetes patients. Initial scans of allelic association were followed by more detailed logistic regression modeling that adjusted for known type I diabetes risk factors and potential confounding variables. The single nucleotide polymorphism (SNP) rs6598, located in a polyadenylation signal of GIMAP5, was associated with the presence of significant levels of IA-2 autoantibodies in the type I diabetes patients. Patients with the minor allele A of rs6598 had an increased prevalence of IA-2 autoantibody levels compared to patients without the minor allele (OR=2.2; Bonferroni-corrected P=0.003), after adjusting for age at clinical onset (P=8.0 x 10(-13)) and the numbers of HLA-DQ A1*0501-B1*0201 haplotypes (P=2.4 x 10(-5)) and DQ A1*0301-B1*0302 haplotypes (P=0.002). GIMAP5 polymorphism was not associated with type I diabetes or with GAD65 or insulin autoantibodies, ICA, or age at clinical onset in patients. These data suggest that the GIMAP5 gene is associated with islet autoimmunity in type I diabetes and add to recent findings implicating the same SNP in another autoimmune disease.
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| 3. |
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| 4. |
- Sako, Masao, et al.
(författare)
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The Data Release of the Sloan Digital Sky Survey-II Supernova Survey
- 2018
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Ingår i: Publications of the Astronomical Society of the Pacific. - : IOP Publishing. - 0004-6280 .- 1538-3873. ; 130:988
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Tidskriftsartikel (refereegranskat)abstract
- This paper describes the data release of the Sloan Digital Sky Survey-II (SDSS-II) Supernova Survey conducted between 2005 and 2007. Light curves, spectra, classifications, and ancillary data are presented for 10,258 variable and transient sources discovered through repeat ugriz imaging of SDSS Stripe 82, a 300 deg(2) area along the celestial equator. This data release is comprised of all transient sources brighter than r similar or equal to 22.5 mag with no history of variability prior to 2004. Dedicated spectroscopic observations were performed on a subset of 889 transients, as well as spectra for thousands of transient host galaxies using the SDSS-III BOSS spectrographs. Photometric classifications are provided for the candidates with good multi-color light curves that were not observed spectroscopically, using host galaxy redshift information when available. From these observations, 4607 transients are either spectroscopically confirmed, or likely to be, supernovae, making this the largest sample of supernova candidates ever compiled. We present a new method for SN host-galaxy identification and derive host-galaxy properties including stellar masses, star formation rates, and the average stellar population ages from our SDSS multi-band photometry. We derive SALT2 distance moduli for a total of 1364 SN. Ia with spectroscopic redshifts as well as photometric redshifts for a further 624 purely photometric SN. Ia candidates. Using the spectroscopically confirmed subset of the three-year SDSS-II SN. Ia sample and assuming a flat.CDM cosmology, we determine Omega(M) = 0.315 +/- 0.093 (statistical error only) and detect a non-zero cosmological constant at 5.7 sigma.
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| 5. |
- Sedimbi, S. K., et al.
(författare)
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SUMO4 M55V polymorphism affects susceptibility to type I diabetes in HLA DR3- and DR4-positive Swedish patients
- 2007
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Ingår i: Genes Immun. - : Springer Science and Business Media LLC. - 1466-4879 .- 1476-5470. ; 8:6, s. 518-21
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Tidskriftsartikel (refereegranskat)abstract
- SUMO4 M55V, located in IDDM5, has been a focus for debate because of its association to type I diabetes (TIDM) in Asians but not in Caucasians. The current study aims to test the significance of M55V association to TIDM in a large cohort of Swedish Caucasians, and to test whether M55V is associated in those carrying human leukocyte antigen (HLA) class II molecules. A total of 673 TIDM patients and 535 age- and sex-matched healthy controls were included in the study. PCR-RFLP was performed to identify the genotype and allele variations. Our data suggest that SUMO4 M55V is not associated with susceptibility to TIDM by itself. When we stratified our patients and controls based on heterozygosity for HLA-DR3/DR4 and SUMO4 genotypes, we found that presence of SUMO4 GG increased further the relative risk conferred by HLA-DR3/DR4 to TIDM, whereas SUMO4 AA decreased the risk. From the current study, we conclude that SUMO4 M55V is associated with TIDM in association with high-risk HLA-DR3 and DR4, but not by itself.
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| 6. |
- Sun, Chengjun, et al.
(författare)
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CRYAB-650 C>G (rs2234702) affects susceptibility to type 1 diabetes and IAA-positivity in Swedish population
- 2012
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Ingår i: Human Immunology. - : Elsevier. - 0198-8859 .- 1879-1166. ; 73:7, s. 759-766
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Single nucleotide polymorphisms (SNPs) in the promoter region of CRYAB gene have been associated with in multiple sclerosis. CRYAB gene, which encodes alpha B-crystallin (a member of small heat shock protein), was reported as a potential autoimmune target. In this study we investigated whether SNPs in the promoter region of CRYAB gene were also important in the etiology of Type 1 diabetes (T1D).METHODS: Genotyping of SNPs in the promoter region of CRYAB gene was performed in a Swedish cohort containing 444 T1D patients and 350 healthy controls. Three SNPs were included in this study: CRYAB-652 A>G (rs762550), -650 C>G (rs2234702) and -249 C > G (rs14133). Two SNPs (CRYAB-652 and -650) were not included in previous genome wide association studies.RESULTS: CRYAB-650 (rs2234702)*C allele was significantly more frequent in patients than in controls (OR = 1.48, Pc = 0.03). CRYAB-650*C allele was associated with IAA positivity (OR = 8.17, Pc < 0.0001) and IA-2A positivity (OR = 2.14, Pc = 0.005) in T1D patients. This association with IAA was amplified by high-risk HLA carrier state (OR = 10.6, P < 0.0001). No association was found between CRYAB-650 and other autoantibody positivity (GADA and ICA). CRYAB haplotypes were also associated with IAA and IA-2A positivity (highest OR = 2.07 and 2.11, respectively), these associations remain in high HLA-risk T1D patients.CONCLUSIONS: CRYAB-650 was associated with T1D in the Swedish cohort we studied. CRYAB-650*C allele might confers susceptibility to the development of T1D. CRYAB-650 was also associated with the development of IAA-positivity in T1D patients, especially in those carrying T1D high-risk HLA haplotypes.
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| 7. |
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| 8. |
- Östman, Jan, et al.
(författare)
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Ketoacidosis in young adults is not related to the islet antibodies at the diagnosis of Type 1 diabetes mellitus - A nationwide study
- 2000
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Ingår i: Diabetic Medicine. - : Wiley. - 0742-3071 .- 1464-5491. ; 17, s. 269-
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Tidskriftsartikel (refereegranskat)abstract
- Aims: To test the hypothesis that there is lower prevalence of islet antibodies in subjects with newly diagnosed Type 1 diabetes mellitus in young adulthood than in children is associated with less severe diabetes at time of diagnosis. Methods: This investigation was based on a nationwide study (Diabetes Incidence Study in Sweden) of 15-34-year-old newly diagnosed diabetic subjects. During 1992-1993, all diabetic subjects (excluding secondary and gestational diabetes) were reported on standardized forms, with information about clinical characteristics at diagnosis. The study examined islet cell antibodies (ICA) by indirect immunofluorescence, and autoantibodies to glutamic acid decarboxylase (GADA), tyrosine phosphatase- like antigen (IA-2A) and insulin (IAA) as well as C-peptide by radioimmunoassay. Results: Blood samples were available from 78 patients with diabetic ketoacidosis (DKA) and 517 non-acidotic patients. The prevalence of ICA (63% vs. 57%), GADA (63% vs. 66%), IA-2A (35% vs. 44%) and IAA (20% vs. 15%) were very similar in patients with or without DKA. The median levels of the four autoantibodies did not differ between the two groups. High blood glucose (P < 0.001) and low C-peptide levels (P < 0.001) were the only parameters found to be related to DKA. Conclusions: The similarities in findings of newly diagnosed diabetic patients with or without DKA regarding ICA, GADA, IA-2A and IAA suggest that there is no relationship between the expression of antigenicity and the severity of β-cell dysfunction. The lower prevalence of the four autoantibodies in 15-34-year-old diabetic subjects compared with previous findings in children is not explained by misclassification of diabetes type.
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| 9. |
- Amanullah, Rahman, et al.
(författare)
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Spectra and Hubble Space Telescope Light Curves of Six Type Ia Supernovae at 0.511 < z < 1.12 and the Union2 Compilation
- 2010
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Ingår i: Astrophysical Journal. - 0004-637X .- 1538-4357. ; 716, s. 712-738
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Tidskriftsartikel (refereegranskat)abstract
- We report on work to increase the number of well-measured Type Ia supernovae (SNe Ia) at high redshifts. Light curves, including high signal-to-noise Hubble Space Telescope data, and spectra of six SNe Ia that were discovered during 2001, are presented. Additionally, for the two SNe with z > 1, we present ground-based J-band photometry from Gemini and the Very Large Telescope. These are among the most distant SNe Ia for which ground-based near-IR observations have been obtained. We add these six SNe Ia together with other data sets that have recently become available in the literature to the Union compilation. We have made a number of refinements to the Union analysis chain, the most important ones being the refitting of all light curves with the SALT2 fitter and an improved handling of systematic errors. We call this new compilation, consisting of 557 SNe, the Union2 compilation. The flat concordance ΛCDM model remains an excellent fit to the Union2 data with the best-fit constant equation-of-state parameter w = -0.997+0.050 -0.054(stat)+0.077 -0.082(stat + sys together) for a flat universe, or w = -1.038+0.056 -0.059(stat)+0.093 -0.097(stat + sys together) with curvature. We also present improved constraints on w(z). While no significant change in w with redshift is detected, there is still considerable room for evolution in w. The strength of the constraints depends strongly on redshift. In particular, at z >~ 1, the existence and nature of dark energy are only weakly constrained by the data. Based in part on observations made with the NASA/ESA Hubble Space Telescope, obtained from the data archive at the Space Telescope Science Institute (STScI). STScI is operated by the Association of Universities for Research in Astronomy (AURA), Inc. under the NASA contract NAS 5-26555. The observations are associated with programs HST-GO-08585 and HST-GO-09075. Based, in part, on observations obtained at the ESO La Silla Paranal Observatory (ESO programs 67.A-0361 and 169.A-0382). Based, in part, on observations obtained at the Cerro-Tololo Inter-American Observatory (CTIO), National Optical Astronomy Observatory (NOAO). Based on observations obtained at the Canada-France-Hawaii Telescope (CFHT). Based, in part, on observations obtained at the Gemini Observatory (Gemini programs GN-2001A-SV-19 and GN-2002A-Q-31). Based, in part on observations obtained at the Subaru Telescope. Based, in part, on data that were obtained at the W. M. Keck Observatory.
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