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- Rachmeler, L. A., et al.
(författare)
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Quiet Sun Center to Limb Variation of the Linear Polarization Observed by CLASP2 Across the Mg ıı h and k Lines
- 2022
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 936:1
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Tidskriftsartikel (refereegranskat)abstract
- The CLASP2 (Chromospheric LAyer Spectro-Polarimeter 2) sounding rocket mission was launched on 2019 April 11. CLASP2 measured the four Stokes parameters of the Mg ıı h and k spectral region around 2800 Å along a 200'' slit at three locations on the solar disk, achieving the first spatially and spectrally resolved observations of the solar polarization in this near-ultraviolet region. The focus of the work presented here is the center-to-limb variation of the linear polarization across these resonance lines, which is produced by the scattering of anisotropic radiation in the solar atmosphere. The linear polarization signals of the Mg ıı h and k lines are sensitive to the magnetic field from the low to the upper chromosphere through the Hanle and magneto-optical effects. We compare the observations to theoretical predictions from radiative transfer calculations in unmagnetized semiempirical models, arguing that magnetic fields and horizontal inhomogeneities are needed to explain the observed polarization signals and spatial variations. This comparison is an important step in both validating and refining our understanding of the physical origin of these polarization signatures, and also in paving the way toward future space telescopes for probing the magnetic fields of the solar upper atmosphere via ultraviolet spectropolarimetry.
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- Vilaplana-Perez, A., et al.
(författare)
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Association of social anxiety disorder with objective indicators of educational attainment : A nation-wide register-based sibling control study
- 2019
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Ingår i: European Neuropsychopharmacology. - : Elsevier. - 0924-977X .- 1873-7862. ; 29:Suppl. 6, s. S150-S151
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Background: Social Anxiety Disorder (SAD) is a relatively frequent psychiatric disorder, with a lifetime prevalence of about 4% [1], which usually starts in adolescence [2]. As in the case of other mental disorders, [3] SAD has also been linked to academic impairment and school drop-out [4,5], but this previous research has a number of methodological limitations, mainly the use of modest sample sizes, retrospective designs, self-reported measures, and focusing in a single educational level.Aim: We aim to investigate the association between SAD and educational outcomes at all levels using objectively collected measures, controlling for a number of covariates and unmeasured factors shared between siblings.Method: Using the Swedish nationwide registers, we designed this population-based birth cohort study, which included 2,244,191 individuals born in Sweden between 1973 and 1997, who were followed up from 1991 until 2013. A total of 15,765 individuals had a record of SAD in the Swedish National Patient Register, according to the International Classification of Diseases, 10th edition. Logistic regression models tested the association between SAD and the prospectively-collected and objectively measured educational outcomes. These educational milestones included: the year grades in the final year of compulsory school, the eligibility to access upper secondary school after compulsory education (for both, vocational and academical programs), finishing upper secondary school, starting university, finishing a university degree, and completing post-graduate education. In order to reduce the impact of possible confounders, we took into account a number of covariates such as age, sex, maternal and paternal age at birth and year of birth. The impact of common psychiatric comorbidities of SAD was also taken into account. In order to control for unmeasured shared familial factors, we performed a sibling comparison analysis. We identified 786,766 families with 2 or more siblings, and identified 11,950 families with full siblings discordant for SAD.Results: Compared to the unexposed individuals, individuals with SAD were less likely to pass all subjects in the last year of compulsory school (adjusted odds ratios [aOR] ranging from 0.19 to 0.44). They were also less likely to access a vocational program or an academic program in upper secondary education (aOR=0.31 [95% CI, 0.30–0.33] and aOR=0.52 [95% CI, 0.51–0.55], respectively). SAD cases also had 81% lower odds of finishing upper secondary education (aOR=0.19 [95% CI, 0.19–0.20]), 53% lower odds of starting a university degree (aOR=0.47 [95% CI, 0.45–0.49]), 65% lower odds of finishing a university degree (aOR=0.35 [95% CI, 0.33–0.37]), and 42% lower odds of finishing postgraduate education (aOR=0.58 [95% CI, 0.43-0.80]). Results were attenuated but remained significant in fully adjusted sibling comparison models. When comorbidities were taken into account, results were maintained.Conclusion: SAD has an adverse impact on educational attainment throughout the life-span, even after controlling for confounders and factors shared between siblings.
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- Ran, Liang, et al.
(författare)
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Genome Erosion in a Nitrogen-Fixing Vertically Transmitted Endosymbiotic Multicellular Cyanobacterium
- 2010
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 5:7
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Tidskriftsartikel (refereegranskat)abstract
- Background: An ancient cyanobacterial incorporation into a eukaryotic organism led to the evolution of plastids (chloroplasts) and subsequently to the origin of the plant kingdom. The underlying mechanism and the identities of the partners in this monophyletic event remain elusive.Methodology/Principal Findings: To shed light on this evolutionary process, we sequenced the genome of a cyanobacterium residing extracellularly in an endosymbiosis with a plant, the water-fern Azolla filiculoides Lam. This symbiosis was selected as it has characters which make it unique among extant cyanobacterial plant symbioses: the cyanobacterium lacks autonomous growth and is vertically transmitted between plant generations. Our results reveal features of evolutionary significance. The genome is in an eroding state, evidenced by a large proportion of pseudogenes (31.2%) and a high frequency of transposable elements (,600) scattered throughout the genome. Pseudogenization is found in genes such as the replication initiator dnaA and DNA repair genes, considered essential to free-living cyanobacteria. For some functional categories of genes pseudogenes are more prevalent than functional genes. Loss of function is apparent even within the ‘core’ gene categories of bacteria, such as genes involved in glycolysis and nutrient uptake. In contrast, serving as a critical source of nitrogen for the host, genes related to metabolic processes such as cell differentiation and nitrogen-fixation are well preserved.Conclusions/Significance: This is the first finding of genome degradation in a plant symbiont and phenotypically complex cyanobacterium and one of only a few extracellular endosymbionts described showing signs of reductive genome evolution. Our findings suggest an ongoing selective streamlining of this cyanobacterial genome which has resulted in an organism devoted to nitrogen fixation and devoid of autonomous growth. The cyanobacterial symbiont of Azolla can thus be considered at the initial phase of a transition from free-living organism to a nitrogen-fixing plant entity, a transition process which may mimic what drove the evolution of chloroplasts from a cyanobacterial ancestor.
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- Vigil-Stenman, Theoden, et al.
(författare)
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Local hopping mobile DNA implicated in pseudogene formation and reductive evolution in an obligate cyanobacteria-plant symbiosis
- 2015
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Ingår i: BMC Genomics. - : Springer Science and Business Media LLC. - 1471-2164. ; 16
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Tidskriftsartikel (refereegranskat)abstract
- Background: Insertion sequences (ISs) are approximately 1 kbp long jumping genes found in prokaryotes. ISs encode the protein Transposase, which facilitates the excision and reinsertion of ISs in genomes, making these sequences a type of class I (cut-and-paste) Mobile Genetic Elements. ISs are proposed to be involved in the reductive evolution of symbiotic prokaryotes. Our previous sequencing of the genome of the cyanobacterium 'Nostoc azollae' 0708, living in a tight perpetual symbiotic association with a plant (the water fern Azolla), revealed the presence of an eroding genome, with a high number of insertion sequences (ISs) together with an unprecedented large proportion of pseudogenes. To investigate the role of ISs in the reductive evolution of 'Nostoc azollae' 0708, and potentially in the formation of pseudogenes, a bioinformatic investigation of the IS identities and positions in 47 cyanobacterial genomes was conducted. To widen the scope, the IS contents were analysed qualitatively and quantitatively in 20 other genomes representing both free-living and symbiotic bacteria. Results: Insertion Sequences were not randomly distributed in the bacterial genomes and were found to transpose short distances from their original location (local hopping) and pseudogenes were enriched in the vicinity of IS elements. In general, symbiotic organisms showed higher densities of IS elements and pseudogenes than non-symbiotic bacteria. A total of 1108 distinct repeated sequences over 500 bp were identified in the 67 genomes investigated. In the genome of 'Nostoc azollae' 0708, IS elements were apparent at 970 locations (14.3%), with 428 being full-length. Morphologically complex cyanobacteria with large genomes showed higher frequencies of IS elements, irrespective of life style. Conclusions: The apparent co-location of IS elements and pseudogenes found in prokaryotic genomes implies earlier IS transpositions into genes. As transpositions tend to be local rather than genome wide this likely explains the proximity between IS elements and pseudogenes. These findings suggest that ISs facilitate the reductive evolution in for instance in the symbiotic cyanobacterium 'Nostoc azollae' 0708 and in other obligate prokaryotic symbionts.
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| 15. |
- Bhalla, Aditya, et al.
(författare)
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Engineered Lignin in Poplar Biomass Facilitates Cu-Catalyzed Alkaline-Oxidative
- 2018
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Ingår i: ACS Sustainable Chemistry and Engineering. - : American Chemical Society (ACS). - 2168-0485. ; 6:3, s. 2932-2941
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Tidskriftsartikel (refereegranskat)abstract
- Both untransformed poplar and genetically modified “zip-lignin” poplar, in which additional ester bonds were introduced into the lignin backbone, were subjected to mild alkaline and copper-catalyzed alkaline hydrogen peroxide (Cu-AHP) pretreatment. Our hypothesis was that the lignin in zip-lignin poplar would be removed more easily than lignin in untransformed poplar during this alkaline pretreatment, resulting in higher sugar yields following enzymatic hydrolysis. We observed improved glucose and xylose hydrolysis yields for zip-lignin poplar compared to untransformed poplar following both alkaline-only pretreatment (56% glucose yield for untransformed poplar compared to 67% for zip-lignin poplar) and Cu-AHP pretreatment (77% glucose yield for untransformed poplar compared to 85% for zip-lignin poplar). Compositional analysis, glycome profiling, and microscopy all supported the notion that the ester linkages increase delignification and improve sugar yields. Essentially no differences were noted in the molecular weight distributions of solubilized lignins between the zip-lignin poplar and the control line. Significantly, when zip-lignin poplar was utilized as the feedstock, hydrogen peroxide, catalyst, and enzyme loadings could all be substantially reduced while maintaining high sugar yields.
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| 20. |
- Enander, J., et al.
(författare)
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Prevalence and heritability of body dysmorphic symptoms in adolescents and young adults: a population-based nationwide twin study
- 2018
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Ingår i: Psychological Medicine. - : Cambridge University Press (CUP). - 0033-2917 .- 1469-8978. ; 48:16, s. 2740-2747
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Tidskriftsartikel (refereegranskat)abstract
- Background. Body dysmorphic disorder (BDD) usually begins during adolescence but little is known about the prevalence, etiology, and patterns of comorbidity in this age group. We investigated the prevalence of BDD symptoms in adolescents and young adults. We also report on the relative importance of genetic and environmental influences on BDD symptoms, and the risk for co-existing psychopathology. Methods. Prevalence of BDD symptoms was determined by a validated cut-off on the Dysmorphic Concerns Questionnaire (DCQ) in three population-based twin cohorts at ages 15 (n = 6968), 18 (n = 3738), and 20-28 (n = 4671). Heritability analysis was performed using univariate model-fitting for the DCQ. The risk for co-existing psychopathology was expressed as odds ratios (OR). Results. The prevalence of clinically significant BDD symptoms was estimated to be between 1 and 2% in the different cohorts, with a significantly higher prevalence in females (1.3-3.3%) than in males (0.2-0.6%). The heritability of body dysmorphic concerns was estimated to be 49% (95% CI 38-54%) at age 15, 39% (95% CI 30-46) at age 18, and 37% (95% CI 29-42) at ages 20-28, with the remaining variance being due to non-shared environment. ORs for co-existing neuropsychiatric and alcohol-related problems ranged from 2.3 to 13.2. Conclusions. Clinically significant BDD symptoms are relatively common in adolescence and young adulthood, particularly in females. The low occurrence of BDD symptoms in adolescent boys may indicate sex differences in age of onset and/or etiological mechanisms. BDD symptoms are moderately heritable in young people and associated with an increased risk for co-existing neuropsychiatric and alcohol-related problems.
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| 22. |
- Ishikawa, Ryohko, et al.
(författare)
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Mapping solar magnetic fields from the photosphere to the base of the corona
- 2021
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Ingår i: Science Advances. - : American Association for the Advancement of Science (AAAS). - 2375-2548. ; 7:8
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Tidskriftsartikel (refereegranskat)abstract
- Routine ultraviolet imaging of the Sun’s upper atmosphere shows the spectacular manifestation of solar activity; yet, we remain blind to its main driver, the magnetic field. Here, we report unprecedented spectropolarimetric observations of an active region plage and its surrounding enhanced network, showing circular polarization in ultraviolet (Mg ii h & k and Mn i) and visible (Fe i) lines. We infer the longitudinal magnetic field from the photosphere to the very upper chromosphere. At the top of the plage chromosphere, the field strengths reach more than 300 G, strongly correlated with the Mg ii k line core intensity and the electron pressure. This unique mapping shows how the magnetic field couples the different atmospheric layers and reveals the magnetic origin of the heating in the plage chromosphere.
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| 26. |
- Song, Donguk, et al.
(författare)
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Polarization Accuracy Verification of the Chromospheric LAyer SpectroPolarimeter
- 2022
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Ingår i: Solar Physics. - : Springer Science and Business Media LLC. - 0038-0938 .- 1573-093X. ; 297:10
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Tidskriftsartikel (refereegranskat)abstract
- We have developed an advanced UV spectropolarimeter called Chromospheric LAyer SpectroPolarimeter (CLASP2), aimed at achieving very high accuracy measurements (<0.1% at 3σ) of the linear (Q/I and U/I) and circular (V/I) polarizations of the Mg II h and k lines (280 nm). CLASP2 was launched on board a NASA sounding rocket on April 11, 2019. It successfully detected the full Stokes vector in an active-region plage and in the quiet Sun near the limb across the Mg II h and k lines for the first time. To verify the polarization characteristics of CLASP2, the response matrix is estimated by combining the results obtained from the preflight calibration on the ground, with the results of the inflight calibration acquired at the solar-disk center. We find that the response matrix of CLASP2 in the Mg II h and k lines is notably close to an ideal response matrix, i.e., the scale factor and the crosstalk terms are close to 1 and 0, respectively. Moreover, the uncertainty of each Stokes parameter estimated by the repeatability of the measurements is verified to be within the required tolerance. Based on our investigation, we conclude that CLASP2 achieves 0.1% polarization accuracy at a 3σ3σ level.
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| 27. |
- Vilaplana-Pérez, Alba, et al.
(författare)
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Assessment of Posttraumatic Stress Disorder and Educational Achievement in Sweden.
- 2020
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Ingår i: JAMA Network Open. - : American Medical Association. - 2574-3805. ; 3:12
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Tidskriftsartikel (refereegranskat)abstract
- Importance: Posttraumatic stress disorder (PTSD) has been associated with impaired educational performance. Previous studies on the disorder could not control for important measured and unmeasured confounders.Objective: To prospectively investigate the association between PTSD and objective indicators of educational attainment across the life span, controlling for familial factors shared by full siblings, psychiatric comorbidity, and general cognitive ability.Design, Setting, and Participants: This population-based cohort study included 2 244 193 individuals born in Sweden between January 1, 1973, and December 31, 1997, who were followed-up until December 31, 2013. Clusters of full siblings were used to account for familial factors. Data analyses were conducted between December 2018 and May 2020.Exposure: International Classification of Diseases, Ninth Revision and International Statistical Classification of Diseases and Related Health Problems, Tenth Revision diagnoses of PTSD in the Swedish National Patient Register.Main Outcomes and Measures: Eligibility to access upper secondary education after finishing compulsory education, finishing upper secondary education, starting a university degree, and finishing a university degree.Results: Of the final cohort of 2 244 193 individuals (1 151 414 [51.3%] men) included in the analysis, 1 425 326 were assessed for finishing compulsory education (919 with PTSD), 2 001 944 for finishing upper secondary education (2013 with PTSD), and 1 796 407 and 1 356 741 for starting and finishing a university degree (2243 and 2254 with PTSD, respectively). Posttraumatic stress disorder was associated with lower odds of achieving each of the educational milestones during the study period, including 82% lower odds of finishing compulsory education (adjusted odds ratio [aOR], 0.18; 95% CI, 0.15-0.20), 87% lower odds of finishing upper secondary education (aOR, 0.13; 95% CI, 0.12-0.14), 68% lower odds of starting a university degree (aOR, 0.32; 95% CI, 0.28-0.35), and 73% lower odds of finishing a university degree (aOR, 0.27; 95% CI, 0.23-0.31). Estimates in the sibling comparison were attenuated (aOR range, 0.22-0.53) but remained statistically significant. Overall, excluding psychiatric comorbidities and adjusting for the successful completion of the previous milestone and general cognitive ability did not statistically significantly alter the magnitude of the associations.Conclusions and Relevance: Posttraumatic stress disorder was associated with educational impairment across the life span, and the associations were not entirely explained by shared familial factors, psychiatric comorbidity, or general cognitive ability. This finding highlights the importance of implementing early trauma-informed interventions in schools and universities to minimize the long-term socioeconomic consequences of academic failure in individuals with PTSD.
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