Publikationer från Uppsala Universitet
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On the band gap variation in CH3NH3Pb(I1−xBrx)3
No full textThe electronic structure and the band gap behavior of CH3NH3Pb(I1−xBrx)3 for x = 0.25, 0.33, 0.50, 0.67, 0.75, 1.00 were studied using the full-relativistic density-functional-theory calculations. A combination of the parameter-free Armiento–Kümmel generalized gradient approximation exchange functional with the nonseparable gradient approximation Minnesota correlation functional was employed. The calculated band gap sizes for the CH3NH3Pb(I1−xBrx)3 series were found to be similar to the experimentally measured values. While the change of the optimized lattice parameter with an increasing Br content can be described by a linear fit, the calculated band gap variation exhibits rather a quadratic-like behavior over the x region of the cubic crystal structure. While the experimental reports are divided on whether the bowing parameter value is being very small or significant, our calculated results support the latter case
Autoantibodies as prognostic markers in rheumatoid arthritis
No full textBackground and purpose Rheumatoid arthritis (RA) is a chronic inflammatory disorder characterized by progressively destructive polyarthritis. Key autoimmune features include the presence of autoantibodies. The purpose of this review is to discuss the diagnostic and prognostic properties of rheumatoid factor (RF) and anti-citrullinated protein/peptide antibodies (ACPA), based on current use in Sweden. Furthermore, we discuss their relation to disease outcomes and their importance for management of patients with RA. Principal findings Based on current cut-offs, ACPA has a higher specificity for RA than RF, and testing for ACPA alone is recommended when investigating patients with clinically suspect RA. The diagnostic utility of RF may improve with adjusted reference range/upper limit of normal. RF and ACPA both predict rapid radiographic progression, severe extra-articular manifestations and mortality, whereas other outcomes, such as osteoporosis, pain and disability are not as clearly related to seropositivity. RF/ACPA positive patients respond better to some targeted therapies, in particular rituximab, compared to seronegative RA patients. Recent studies indicate that treatment of ACPA-positive arthralgia with abatacept may delay and perhaps sometimes even prevent development of arthritis. Available evidence does not support an added value of repeated RF or ACPA testing. Conclusions Testing for ACPA in patients with arthralgia or suspected early RA, and for ACPA and RF at RA diagnosis, provides useful diagnostic and prognostic information, which has implications for follow-up and treatment. Repeated testing for ACPA and RF is not recommended. Potential future developments include treatment of ACPA-positive individuals for prevention of arthritis
A main sequence CH-star in the globular cluster M55 (NGC 6809)
No full textSpectra have been obtained with the multi-fibre instrument 2dF on the Anglo-Australian Telescope of 89 candidate main sequence stars in the globular cluster M55 (NGC 6809). Radial velocities and Gaia proper motions confirm 72 candidates as cluster members. Among these stars one stands out as having a substantially stronger G-band (CH) than the rest of the member sample. The star is a dwarf carbon star that most likely acquired the high carbon abundance ([C/Fe] ≈ 1.2 ± 0.2) via mass transfer from a ∼1−3 M⊙ binary companion (now a white dwarf) during its AGB phase of evolution. Interestingly, M55 also contains a CH-star that lies on the cluster red giant branch – the low central concentration/low density of this cluster presumably allows the survival of binaries that would otherwise be disrupted in denser systems. The existence of carbon stars in six other globular clusters is consistent with this hypothesis, while the origin of the carbon-enhanced star in M15 (NGC 7078) is attributed to a merger process similar to that proposed for the origin of the carbon-rich R stars
Off-shell color-kinematics duality from codifferentials
No full textWe examine the color-kinematics duality within the BV formalism, highlighting its emergence as a feature of specific gauge-fixed actions. Our goal is to establish a general framework for studying the duality while investigating straightforward examples of off-shell color-kinematics duality. In this context, we revisit Chern-Simons theory as well as introduce new examples, including BF theory and 2D Yang-Mills theory, which are shown to exhibit the duality off-shell. We emphasize that the geometric structures responsible for flat-space color-kinematics duality appear for general curved spaces as well
Analytical and Numerical approximations of Calabi Yau Metrics
No full textThe problem of finding analytical expression for Ricci-flat metrics on Calabi-Yau manifolds lies atthe interface between mathematics and theoretical physics with deep implications for string theory and phenomenology. Recently, this interface has gained a third boundary in machine learning (ML) with methods that approximate the true metric using ML tools such as neural networks. In this thesis, we explore the state-of-the-art machine learning solutions applied to the Fermat quintic. Additionally, we employ modified versions that leverage the manifold’s high degree of symmetry to obtain highly accurate approximations of the Kähler potential corresponding to the Ricci-flat metric. Analytical expressions are then matched to these approximations of the true Kähler potential using symbolic regression, by utilizing the SR library PySR which evolves expression trees representing analytical expressions using genetic algorithms to maximize the fit to some training data. Additionally, when analyzing the numerical approximations they are found to have more symmetries than the underlying geometry which are used to simplify the input space to the symbolic regressor. The analytical expressions obtained, although not the exact Calabi-Yau Kähler potential, achieve better scores than the Fubini-Study metric, with standard loss measures gaining two orders of magnitude compared to those for the latter
ADHD and Identity Formation : Adolescents' Experiences From the Healthcare System and Peer Relationships
No full textObjective: ADHD is often a lifelong condition, and has grown increasingly prevalent over the past few decades. Adolescence is a period characterized by the quest to develop a coherent identity, yet relatively little research has examined the relationship between ADHD diagnosis and identity. The purpose of this study was to explore the importance of experiences of the healthcare system and of peer relationships in the identity formation of adolescents with ADHD. Method: This was investigated through semi-structured interviews with 10 adolescents (n = 8 females and 2 males) aged 15 to 18 years. An inductive thematic analysis was conducted within a narrative framework. Results: The results revealed seven main themes indicating that ADHD played a central role in the adolescents' self-narratives: (1) limited effect of Child and Adolescent Psychiatry (CAP) contact on identity formation, (2) the ADHD concept as meaning-making, (3) heterogeneity of the role of medication on identity formation, (4) negotiation of identity in relation to others, (5) varying degrees of acceptance in different relationships, (6) perceiving oneself as a troublemaker, and (7) relationship difficulties. Conclusions: Overall, the diagnosis constituted an important narrative and symptoms of ADHD rather than the label of ADHD tended to be stigmatizing. Furthermore, medication affected identity, and some felt pressured to medicate to adhere to social norms. A common pattern was that adolescents set aside their individual identity in favor of their relational identity
Prevalence of microspirometry-detected chronic obstructive pulmonary disease in two European cohorts of patients hospitalised for acute myocardial infarction : a cross-sectional study
No full textObjectives: To establish the prevalence of clinically significant chronic obstructive pulmonary disease (COPD) and relevant characteristics in individuals with a significant smoking history who are hospitalised for acute myocardial infarction (MI). Design: Cross-sectional study. Setting: Hospital inpatients at 8 European centres (7 in Sweden, 1 in the UK). Participants: 518 men or women (302 in Sweden, 216 in the UK) hospitalised for acute MI, aged 40 years or older, with a smoking history of at least 10 pack-years. Primary and secondary outcome measures: The primary outcome was prevalence of detected significant COPD (Global Initiative for Chronic Obstructive: Lung Disease stages 2-4), defined as a ratio of forced expiratory volume in 1 and 6 s (FEV1/FEV6) <0.7 and FEV1 <80% of the predicted value, measured using microspirometry. Secondary outcome measures were prior diagnosis of COPD, prescription of inhaled corticosteroids (ICS), symptom burden (COPD Assessment Test (CAT)) and blood eosinophil count. Results: The prevalence of significant COPD was 91/518 (18% (95% CI 14 to 21)) with no difference between the countries. Of those with detected significant COPD, 69 (76%) had no previous COPD diagnosis. A CAT score >10 was found in 65%, and a blood eosinophil count of >= 100/mm(3) and >= 300/mm(3) was found in 76% and 20%, respectively. Inhaled corticosteroids were used by 15% of the patients. Conclusions: In a cohort of patients hospitalised for acute MI in Sweden and the UK, one in five patients with a history of smoking was found to have significant COPD based on microspirometry. Symptom burden was high and treatment rates with ICS low. Among those diagnosed with COPD, three out of four had not been previously diagnosed with COPD
Significant Associations Between Blood Cell Counts and Plasma Cytokines, Chemokines, and Growth Factors
No full textThe cytokine network plays a crucial role in regulating immune responses and facilitating intercellular communication. Cytokines are essential in numerous physiological and pathological processes. This study aimed to investigate associations between blood cell counts and a broad range of cytokines, chemokines, and growth factors. We included one hundred and sixty-five essentially healthy individuals in this study, which was approved by the Swedish Ethical Review Authority (Dnr 2015/378) and registered in EudraCT (2014-004235-39). Blood samples were collected for blood cell counts and analysis of cytokines, chemokines, and growth factors using the Proseek Multiplex Inflammation kit, Olink Bioscience, Uppsala, Sweden. Correlations between the different markers were calculated using Spearman rank correlations, adjusted for multiplicity and for multiple testing, with a significance threshold of p < 0.05. There were significant associations between platelet count and 23 cytokines, between white blood cell count and 8 cytokines, and between erythrocyte volume fractions and 19 cytokines. IL-6 had a central role within the cytokine network associated with platelets and was also associated with white blood cells and neutrophil cells. These findings emphasize the integrated nature of immune and hematological responses, where blood cell parameters are associated with systemic cytokine activity. The observed intercytokine associations, including cross-family interactions, may help to highlight regulatory pathways, providing potential targets for biomarker development and therapeutic intervention in immune-mediated conditions
Development cooperation and the stratification of lesbian, gay, bi- and transsexual activism : international donors, elite activists and community members during Uganda Pride 2022
No full textUganda’s infamous state-sanctioned homo-hostility has resulted in intense international attention, development cooperation and Western funding to local lesbian, gay, bi- and transsexual (LGBT+) organisations. However, Western funders and allies in this context are becoming increasingly questioned. Researchers have highlighted the complexities, opportunities and constraints of an increasingly transnational LGBT+ movement, but how is this manifested on the ground in the Global South? Through an inductive and ethnographically inspired study, we set out to explore the Ugandan LGBT+ community and its intra-community relationships and relations with Western funders and allies in the unique setting of Uganda Pride 2022, to which we had rare first-hand access. The results reveal that security concerns, both from outside and within the community, shaped Uganda Pride 2022. The most salient finding is that competition for international funding distorts activists’ relations, as it stratifies the LGBT+ community based on who has access to Western donors and international funders
Measurement of the Born cross section for +− →ℎ at center-of-mass energies between 4.1 and 4.6 GeV
No full textWe measure the Born cross section for the reaction +−→ℎ from √ =4.129 to 4.600 GeV using datasets collected by the BESIII detector running at the BEPCII collider. A resonant structure in the cross-section line shape near 4.200 GeV is observed with a statistical significance of 7. The parameters of this resonance are measured to be =4188.8±4.7±8.0 MeV/2 and Γ=49±16±19 MeV, where the first uncertainties are statistical and the second systematic.For complete list of authors see http://dx.doi.org/10.1103/PhysRevD.111.L011101</p